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Sample records for machined aluminum surface

  1. Cleaning of aluminum after machining with coolants

    International Nuclear Information System (INIS)

    Roop, B.

    1992-01-01

    An x-ray photoemission spectroscopic study was undertaken to compare the cleaning of the Advanced Photon Source (APS) aluminum extrusion storage ring vacuum chambers after machining with and without water soluble coolants. While there was significant contamination left by the coolants, the cleaning process was capable of removing the residue. The variation of the surface and near surface composition of samples machined either dry or with coolants was negligible after cleaning. The use of such coolants in the machining process is therefore recommended

  2. Evaluation of Fatigue Behavior and Surface Characteristics of Aluminum Alloy 2024 T6 After Electric Discharge Machining

    Science.gov (United States)

    Mehmood, Shahid; Shah, Masood; Pasha, Riffat Asim; Sultan, Amir

    2017-10-01

    The effect of electric discharge machining (EDM) on surface quality and consequently on the fatigue performance of Al 2024 T6 is investigated. Five levels of discharge current are analyzed, while all other electrical and nonelectrical parameters are kept constant. At each discharge current level, dog-bone specimens are machined by generating a peripheral notch at the center. The fatigue tests are performed on four-point rotating bending machine at room temperature. For comparison purposes, fatigue tests are also performed on the conventionally machined specimens. Linearized SN curves for 95% failure probability and with four different confidence levels (75, 90, 95 and 99%) are plotted for each discharge current level as well as for conventionally machined specimens. These plots show that the electric discharge machined (EDMed) specimens give inferior fatigue behavior as compared to conventionally machined specimen. Moreover, discharge current inversely affects the fatigue life, and this influence is highly pronounced at lower stresses. The EDMed surfaces are characterized by surface properties that could be responsible for change in fatigue life such as surface morphology, surface roughness, white layer thickness, microhardness and residual stresses. It is found that all these surface properties are affected by changing discharge current level. However, change in fatigue life by discharge current could not be associated independently to any single surface property.

  3. Improvement of MRR and surface roughness during electrical discharge machining (EDM) using aluminum oxide powder mixed dielectric fluid

    Science.gov (United States)

    Khan, A. A.; Mohiuddin, A. K. M.; Latif, M. A. A.

    2018-01-01

    This paper discusses the effect of aluminium oxide (Al203) addition to dielectric fluid during electrical discharge machining (EDM). Aluminium oxide was added to the dielectric used in the EDM process to improve its performance when machining the stainless steel AISI 304, while copper was used as the electrode. Effect of the concentration of Al203 (0.3 mg/L) in dielectric fluid was compared with EDM without any addition of Al203. Surface quality of stainless steel and the material removal rate were investigated. Design of the experiment (DOE) was used for the experimental plan. Statistical analysis was done using ANOVA and then appropriate model was designated. The experimental results show that with dispersing of aluminium oxide in dielectric fluid surface roughness was improved while the material removal rate (MRR) was increased to some extent. These indicate the improvement of EDM performance using aluminium oxide in dielectric fluid. It was also found that with increase in pulse on time both MRR and surface roughness increase sharply.

  4. FSW of Aluminum Tailor Welded Blanks across Machine Platforms

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Upadhyay, Piyush; Carlson, Blair; Szymanski, Robert; Luzanski, Tom; Marshall, Dustin

    2015-02-16

    Development and characterization of friction stir welded aluminum tailor welded blanks was successfully carried out on three separate machine platforms. Each was a commercially available, gantry style, multi-axis machine designed specifically for friction stir welding. Weld parameters were developed to support high volume production of dissimilar thickness aluminum tailor welded blanks at speeds of 3 m/min and greater. Parameters originally developed on an ultra-high stiffness servo driven machine where first transferred to a high stiffness servo-hydraulic friction stir welding machine, and subsequently transferred to a purpose built machine designed to accommodate thin sheet aluminum welding. The inherent beam stiffness, bearing compliance, and control system for each machine were distinctly unique, which posed specific challenges in transferring welding parameters across machine platforms. This work documents the challenges imposed by successfully transferring weld parameters from machine to machine, produced from different manufacturers and with unique control systems and interfaces.

  5. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

    Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to anodized surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In

  6. Intelligent Machine Parts with Surface Embedded Sensors

    OpenAIRE

    Østbø, Niels Peter

    2009-01-01

    A surface embedded temperature sensor has successfully been fabricated on a customized industrial bolt. The aluminum substrate of the bolt was electrically isolated by plasma electrolytic oxidation followed by the fabrication of a type T thermocouple and finally covered by a wear resistant DLC coating. This bolt is part of our work to develop smart machine parts that are capable of reporting their current physical status under real working conditions enabling both new tools for condition base...

  7. Machining of Complex Sculptured Surfaces

    CERN Document Server

    2012-01-01

    The machining of complex sculptured surfaces is a global technological topic in modern manufacturing with relevance in both industrialized and emerging in countries particularly within the moulds and dies sector whose applications include highly technological industries such as the automotive and aircraft industry. Machining of Complex Sculptured Surfaces considers new approaches to the manufacture of moulds and dies within these industries. The traditional technology employed in the manufacture of moulds and dies combined conventional milling and electro-discharge machining (EDM) but this has been replaced with  high-speed milling (HSM) which has been applied in roughing, semi-finishing and finishing of moulds and dies with great success. Machining of Complex Sculptured Surfaces provides recent information on machining of complex sculptured surfaces including modern CAM systems and process planning for three and five axis machining as well as explanations of the advantages of HSM over traditional methods ra...

  8. Masking of aluminum surface against anodizing

    Science.gov (United States)

    Crawford, G. B.; Thompson, R. E.

    1969-01-01

    Masking material and a thickening agent preserve limited unanodized areas when aluminum surfaces are anodized with chromic acid. For protection of large areas it combines well with a certain self-adhesive plastic tape.

  9. Evaluation of the Technical-Economic Potential of Particle- Reinforced Aluminum Matrix Composites and Electrochemical Machining

    International Nuclear Information System (INIS)

    Schubert, A; Hackert-Oschätzchen, M; Lehnert, N; Götze, U; Herold, F; Schmidt, A; Meichsner, G

    2016-01-01

    Compared to conventional cutting, the processing of materials by electrochemical machining offers some technical advantages like high surface quality, no thermal or mechanical impact on the work piece and preservation of the microstructure of the work piece material. From the economic point of view, the possibility of process parallelization and the absence of any process-related tool wear are mentionable advantages of electrochemical machining. In this study, based on experimental results, it will be evaluated to what extent the electrochemical machining is technically and economically suitable for the finish-machining of particle- reinforced aluminum matrix composites (AMCs). Initial studies showed that electrochemical machining - in contrast to other machining processes - has the potential to fulfil demanding requirements regarding precision and surface quality of products or components especially when applied to AMCs. In addition, the investigations show that processing of AMCs by electrochemical machining requires less energy than the electrochemical machining of stainless steel. Therefore, an evaluation of electrochemically machined AMCs - compared to stainless steel - from a technical and an economic perspective will be presented in this paper. The results show the potential of electro-chemically machined AMCs and contribute to the enhancement of instruments for technical-economic evaluations as well as a comprehensive innovation control. (paper)

  10. Process capability improvement through DMAIC for aluminum alloy wheel machining

    Science.gov (United States)

    Sharma, G. V. S. S.; Rao, P. Srinivasa; Babu, B. Surendra

    2017-07-01

    This paper first enlists the generic problems of alloy wheel machining and subsequently details on the process improvement of the identified critical-to-quality machining characteristic of A356 aluminum alloy wheel machining process. The causal factors are traced using the Ishikawa diagram and prioritization of corrective actions is done through process failure modes and effects analysis. Process monitoring charts are employed for improving the process capability index of the process, at the industrial benchmark of four sigma level, which is equal to the value of 1.33. The procedure adopted for improving the process capability levels is the define-measure-analyze-improve-control (DMAIC) approach. By following the DMAIC approach, the C p, C pk and C pm showed signs of improvement from an initial value of 0.66, -0.24 and 0.27, to a final value of 4.19, 3.24 and 1.41, respectively.

  11. Optimizing friction stir weld parameters of aluminum and copper using conventional milling machine

    Science.gov (United States)

    Manisegaran, Lohappriya V.; Ahmad, Nurainaa Ayuni; Nazri, Nurnadhirah; Noor, Amirul Syafiq Mohd; Ramachandran, Vignesh; Ismail, Muhammad Tarmizizulfika; Ahmad, Ku Zarina Ku; Daruis, Dian Darina Indah

    2018-05-01

    The joining of two of any particular materials through friction stir welding (FSW) are done by a rotating tool and the work piece material that generates heat which causes the region near the FSW tool to soften. This in return will mechanically intermix the work pieces. The first objective of this study is to join aluminum plates and copper plates by means of friction stir welding process using self-fabricated tools and conventional milling machine. This study also aims to investigate the optimum process parameters to produce the optimum mechanical properties of the welding joints for Aluminum plates and Copper plates. A suitable tool bit and a fixture is to be fabricated for the welding process. A conventional milling machine will be used to weld the aluminum and copper. The most important parameters to enable the process are speed and pressure of the tool (or tool design and alignment of the tool onto the work piece). The study showed that the best surface finish was produced from speed of 1150 rpm and tool bit tilted to 3°. For a 200mm × 100mm Aluminum 6061 with plate thickness of 2 mm at a speed of 1 mm/s, the time taken to complete the welding is only 200 seconds or equivalent to 3 minutes and 20 seconds. The Copper plates was successfully welded using FSW with tool rotation speed of 500 rpm, 700 rpm, 900 rpm, 1150 rpm and 1440 rpm and with welding traverse rate of 30 mm/min, 60 mm/min and 90 mm/min. As the conclusion, FSW using milling machine can be done on both Aluminum and Copper plates, however the weld parameters are different for the two types of plates.

  12. Investigation of aluminum surface cleaning using cavitating fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Ralys, Aurimas; Striška, Vytautas; Mokšin, Vadim [Vilnius Gediminas Technical University, Faculty of Mechanics, Department of Machine Engineering, J. Basanavičiaus str.28, 03224, Vilnius (Lithuania)

    2013-12-16

    This paper investigates efficiency of specially designed atomizer used to spray water and cavitate microbubbles in water flow. Surface cleaning system was used to clean machined (grinded) aluminum surface from abrasive particles. It is established that cleaning efficiency depends on diameter of the diffuser, water pressure and distance between nozzle and metal surface. It is obtained that the best cleaning efficiency (100%) is achieved at pressure 36 bar, when diameter of diffuser is 0.4 mm and distance between nozzle and surface is 1 mm. It is also established that satisfactory cleaning efficiency (80%) is achieved not only when atomizer is placed closer to metal surface, but also at larger (120 mm) distances.

  13. EXPERIMENTAL EVALUATION OF WEDM MACHINED SURFACE WAVINESS

    Directory of Open Access Journals (Sweden)

    Katerina Mouralova

    2016-10-01

    Full Text Available Wire Electrical Discharge Machining (WEDM an unconventional machining technology which has become indispensable in many industries. The typical morphology of a surface machined using the electrical discharge technology is characterized with a large number of craters caused by electro-spark discharges produced during the machining process. The study deals with an evaluation of the machine parameter setting on the profile parameters of surface waviness on samples made of two metal materials Al 99.5 and Ti-6Al-4V. Attention was also paid to an evaluation of the surface morphology using 3D colour filtered and non-filtered images.

  14. Properties of Free-Machining Aluminum Alloys at Elevated Temperatures

    Science.gov (United States)

    Faltus, Jiří; Karlík, Miroslav; Haušild, Petr

    In areas close to the cutting tool the workpieces being dry machined could be heated up to 350°C and they may be impact loaded. Therefore it is of interest to study mechanical properties of corresponding materials at elevated temperatures. Free-machining alloys of Al-Cu and Al-Mg-Si systems containing Pb, Bi and Sn additions (AA2011, AA2111B, AA6262, and AA6023) were subjected to Charpy U notch impact test at the temperatures ranging from 20 to 350°C. The tested alloys show a sharp drop in notch impact strength KU at different temperatures. This drop of KU is caused by liquid metal embrittlement due to the melting of low-melting point dispersed phases which is documented by differential scanning calorimetry. Fracture surfaces of the specimens were observed using a scanning electron microscope. At room temperature, the fractures of all studied alloys exhibited similar ductile dimple fracture micromorphology, at elevated temperatures, numerous secondary intergranular cracks were observed.

  15. Nanoengineered Superhydrophobic Surfaces of Aluminum with Extremely Low Bacterial Adhesivity

    NARCIS (Netherlands)

    Hizal, Ferdi; Rungraeng, Natthakan; Lee, Junghoon; Jun, Soojin; Busscher, Henk J.; van der Mei, Henny C.; Choi, Chang-Hwan

    2017-01-01

    Bacterial adhesion and biofilm formation on surfaces are troublesome in many industrial processes. Here, nanoporous and nanopillared aluminum surfaces were engineered by anodizing and postetching processes and made hydrophilic (using the inherent oxide layer) or hydrophobic (applying a Teflon

  16. A liquid aluminum corrosion resistance surface on steel substrate

    International Nuclear Information System (INIS)

    Wang Deqing; Shi Ziyuan; Zou Longjiang

    2003-01-01

    The process of hot dipping pure aluminum on a steel substrate followed by oxidation was studied to form a surface layer of aluminum oxide resistant to the corrosion of aluminum melt. The thickness of the pure aluminum layer on the steel substrate is reduced with the increase in temperature and time in initial aluminizing, and the thickness of the aluminum layer does not increase with time at given temperature when identical temperature and complete wetting occur between liquid aluminum and the substrate surface. The thickness of the Fe-Al intermetallic layer on the steel base is increased with increasing bath temperature and time. Based on the experimental data and the mathematics model developed by the study, a maximum exists in the thickness of the Fe-Al intermetallic at certain dipping temperature. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis reveals that the top portion of the steel substrate is composed of a thin layer of α-Al 2 O 3 , followed by a thinner layer of FeAl 3 , and then a much thicker one of Fe 2 Al 5 on the steel base side. In addition, there is a carbon enrichment zone in diffusion front. The aluminum oxide surface formed on the steel substrate is in perfect condition after corrosion test in liquid aluminum at 750 deg. C for 240 h, showing extremely good resistance to aluminum melt corrosion

  17. Research of plating aluminum and aluminum foil on internal surface of carbon fiber composite material centrifuge rotor drum

    International Nuclear Information System (INIS)

    Lu Xiuqi; Dong Jinping; Dai Xingjian

    2014-01-01

    In order to improve the corrosion resistance, thermal conductivity and sealability of the internal surface of carbon fiber/epoxy composite material centrifuge rotor drum, magnetron sputtering aluminum and pasting an aluminum foil on the inner wall of the drum are adopted to realize the aim. By means of XRD, SEM/EDS and OM, the surface topography of aluminum coated (thickness of 5 μm and 12 μm) and aluminum foil (12 μm) are observed and analyzed; the cohesion of between aluminum coated (or aluminum foil) and substrate material (CFRP) is measured by scratching experiment, direct drawing experiment, and shear test. Besides, the ultra-high-speed rotation experiment of CFRP ring is carried out to analyze stress and strain of coated aluminum (or aluminum foil) which is adhered on the ring. The results showed aluminum foil pasted on inner surface do better performance than magnetron sputtering aluminum on CFRP centrifuge rotor drum. (authors)

  18. Photoelectron studies of machined brass surfaces

    Science.gov (United States)

    Potts, A. W.; Merrison, J. P.; Tournas, A. D.; Yacoot, A.

    UV photoelectron spectroscopy has been used to determine the surface composition of machined brass. The results show a considerable change between the photoelectron surface composition and the bulk composition of the same sample determined by energy-dispersive X-ray fluorescence. On the surface the lead composition is increased by ˜900 G. This is consistent with the important part that lead is believed to play in improving the machinability of this alloy.

  19. Automatic inspection of surface defects in die castings after machining

    Directory of Open Access Journals (Sweden)

    S. J. Świłło

    2011-07-01

    Full Text Available A new camera based machine vision system for the automatic inspection of surface defects in aluminum die casting was developed by the authors. The problem of surface defects in aluminum die casting is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. The casting surfaces are the most highly loaded regions of materials and components. Mechanical and thermal loads as well as corrosion or irradiation attacks are directed primarily at the surface of the castings. Depending on part design and processing techniques, castings may develop surface discontinuities such as cracks or tears, inclusions due to chemical reactions or foreign material in the molten metal, and pores that greatly influence the material ability to withstand these loads. Surface defects may act as a stress concentrator initiating a fracture point. If a pressure is applied in this area, the casting can fracture. The human visual system is well adapted to perform in areas of variety and change; the visual inspection processes, on the other hand, require observing the same type of image repeatedly to detect anomalies. Slow, expensive, erratic inspection usually is the result. Computer based visual inspection provides a viable alternative to human inspectors. Developed by authors machine vision system uses an image processing algorithm based on modified Laplacian of Gaussian edge detection method to detect defects with different sizes and shapes. The defect inspection algorithm consists of three parameters. One is a parameter of defects sensitivity, the second parameter is a threshold level and the third parameter is to identify the detected defects size and shape. The machine vision system has been successfully tested for the different types of defects on the surface of castings.

  20. Optimizing cutting conditions on sustainable machining of aluminum alloy to minimize power consumption

    Science.gov (United States)

    Nur, Rusdi; Suyuti, Muhammad Arsyad; Susanto, Tri Agus

    2017-06-01

    Aluminum is widely utilized in the industrial sector. There are several advantages of aluminum, i.e. good flexibility and formability, high corrosion resistance and electrical conductivity, and high heat. Despite of these characteristics, however, pure aluminum is rarely used because of its lacks of strength. Thus, most of the aluminum used in the industrial sectors was in the form of alloy form. Sustainable machining can be considered to link with the transformation of input materials and energy/power demand into finished goods. Machining processes are responsible for environmental effects accepting to their power consumption. The cutting conditions have been optimized to minimize the cutting power, which is the power consumed for cutting. This paper presents an experimental study of sustainable machining of Al-11%Si base alloy that was operated without any cooling system to assess the capacity in reducing power consumption. The cutting force was measured and the cutting power was calculated. Both of cutting force and cutting power were analyzed and modeled by using the central composite design (CCD). The result of this study indicated that the cutting speed has an effect on machining performance and that optimum cutting conditions have to be determined, while sustainable machining can be followed in terms of minimizing power consumption and cutting force. The model developed from this study can be used for evaluation process and optimization to determine optimal cutting conditions for the performance of the whole process.

  1. Chemical milling solution produces smooth surface finish on aluminum

    Science.gov (United States)

    Lorenzen, H. C.

    1966-01-01

    Elementary sulfur mixed into a solution of caustic soda and salts produces an etchant which will chemically mill end-grain surfaces on aluminum plate. This composition results in the least amount of thickness variation and pitting.

  2. The effect of surface modification on initial ice formation on aluminum surfaces

    DEFF Research Database (Denmark)

    Rahimi, Maral; Afshari, Alireza; Fojan, Peter

    2015-01-01

    material of heat exchanger fins is aluminum, this paper focuses on the effect of aluminum wettability on the initial stages of ice formation. The ice growth was studied on bare as well as hydrophilically and hydrophobically modified surfaces of aluminum (8011A) sheets, commonly used in heat exchangers...

  3. First-principles surface interaction studies of aluminum-copper and aluminum-copper-magnesium secondary phases in aluminum alloys

    Science.gov (United States)

    da Silva, Thiago H.; Nelson, Eric B.; Williamson, Izaak; Efaw, Corey M.; Sapper, Erik; Hurley, Michael F.; Li, Lan

    2018-05-01

    First-principles density functional theory-based calculations were performed to study θ-phase Al2Cu, S-phase Al2CuMg surface stability, as well as their interactions with water molecules and chloride (Cl-) ions. These secondary phases are commonly found in aluminum-based alloys and are initiation points for localized corrosion. Density functional theory (DFT)-based simulations provide insight into the origins of localized (pitting) corrosion processes of aluminum-based alloys. For both phases studied, Cl- ions cause atomic distortions on the surface layers. The nature of the distortions could be a factor to weaken the interlayer bonds in the Al2Cu and Al2CuMg secondary phases, facilitating the corrosion process. Electronic structure calculations revealed not only electron charge transfer from Cl- ions to alloy surface but also electron sharing, suggesting ionic and covalent bonding features, respectively. The S-phase Al2CuMg structure has a more active surface than the θ-phase Al2Cu. We also found a higher tendency of formation of new species, such as Al3+, Al(OH)2+, HCl, AlCl2+, Al(OH)Cl+, and Cl2 on the S-phase Al2CuMg surface. Surface chemical reactions and resultant species present contribute to establishment of local surface chemistry that influences the corrosion behavior of aluminum alloys.

  4. The improvement of surface roughness for OAP aluminum mirrors: from terahertz to ultraviolet

    Science.gov (United States)

    Peng, Jilong; Yu, Qian; Shao, Yajun; Wang, Dong; Yi, Zhong; Wang, Shanshan

    2018-01-01

    Aluminum reflector, especially OAP (Off-Axis Parabolic) reflector, has been widely used in terahertz and infrared systems for its low cost, lightweight, good machinability, small size, simple structure, and having the same thermal expansion and contraction with the system structure which makes it have a wide temperature adaptability. Thorlabs, Daheng and other large optical components companies even have Aluminum OAP sold on shelf. Most of the precision Aluminum OAP is fabricated by SPDT (single point diamond turing). Affected by intermittent shock, the roughness of aluminum OAP mirrors through conventional single-point diamond lathes is around 7 nm which limits the scope of application for aluminum mirrors, like in the high power density terahertz/infrared systems and visible/UV optical systems. In this paper, a continuous process frock is proposed, which effectively reduces the influence of turning impact on the mirror roughness. Using this process, an off-axis parabolic aluminum reflector with an effective diameter of 50 mm, off-axis angle of 90 degree is fabricated, and the performances are validated. Measurement by VEECO NT1100 optical profiler with 20× objects, the surface roughness achieves 2.3 nm, and the surface figure error is within λ/7 RMS (λ= 632.8 nm) tested by FISB Aμ Phase laser interferometer with the help of a standard flat mirror. All these technical specifications are close to the traditional glass-based reflectors, and make it possible for using Aluminum reflectors in the higher LIDT (laser induced damage threshold) systems and even for the micro sensor of ionospheric for vacuum ultraviolet micro nano satellites.

  5. Investigation of machining damage and tool wear resulting from drilling powder metal aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fell, H.A. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

    1997-05-01

    This report documents the cutting of aluminum powder metallurgy (PM) parts for the North Carolina Manufacturing Extension Partnership. The parts, an aluminum powder metal formulation, were supplied by Sinter Metals Inc., of Conover, North Carolina. The intended use of the alloy is for automotive components. Machining tests were conducted at Y-12 in the machine shop of the Skills Demonstration Center in Building 9737. Testing was done on June 2 and June 3, 1997. The powder metal alloy tested is very abrasive and tends to wear craters and produce erosion effects on the chip washed face of the drills used. It also resulted in huge amounts of flank wear and degraded performance on the part of most drills. Anti-wear coatings on drills seemed to have an effect. Drills with the coating showed less wear for the same amount of cutting. The usefulness of coolants and lubricants in reducing tool wear and chipping/breakout was not investigated.

  6. Optical scattering from rough-rolled aluminum surfaces.

    Science.gov (United States)

    Rönnelid, M; Adsten, M; Lindström, T; Nostell, P; Wäckelgård, E

    2001-05-01

    Bidirectional, angular resolved scatterometry was used to evaluate the feasibility of using rolled aluminum as reflectors in solar thermal collectors and solar cells. Two types of rolled aluminum with different surface roughnesses were investigated. The results show that the smoother of the two samples [rms height, (0.20 ? 0.02) mum] can be used as a nonimaging, concentrating reflector with moderate reflection losses compared with those of optically smooth aluminum reflectors. The sample with the rougher surface [rms height, (0.6 ? 0.1) mum] is not suitable as a concentrating element but can be used as planar reflectors. The orientation of the rolling grooves is then of importance for minimizing reflection losses in the system.

  7. Disordering and Melting of Aluminum Surfaces

    DEFF Research Database (Denmark)

    Stoltze, Per; Nørskov, Jens Kehlet; Landman, U.

    1988-01-01

    We report on a molecular-dynamics simulation of an Al(110) surface using the effective-medium theory to describe the interatomic interactions. The surface region is found to start melting ≅200 K below the bulk melting temperature with a gradual increase in the thickness of the disordered layer as...

  8. A post-processing study on aluminum surface by fiber laser: Removing face milling patterns

    Science.gov (United States)

    Kayahan, Ersin

    2018-05-01

    The face milling process of the metal surface is a well-known machining process of using rotary cutters to remove material from a workpiece. Flat metal surfaces can be produced by a face milling process. However, in practice, visible, traced marks following the motion of points on the cutter's face are usually apparent. In this study, it was shown that milled patterns can be removed by means of 20 W fiber laser on the aluminum surface (AA7075). Experimental results also showed that roughened and hydrophobic surface can be produced with optimized laser parameters. It is a new approach to remove the patterns from the metal surface and can be explained through roughening by re-melting instead of ablation. The new method is a strong candidate to replace sandblasting the metal surface. It is also cheap and environmentally friendly.

  9. Phase Transitions in Aluminum Under Shockless Compression at the Z Machine

    Science.gov (United States)

    Davis, Jean-Paul; Brown, Justin; Shulenburger, Luke; Knudson, Marcus

    2017-06-01

    Aluminum 6061 alloy has been used extensively as an electrode material in shockless ramp-wave experiments at the Z Machine. Previous theoretical work suggests that the principal quasi-isentrope in aluminum should pass through two phase transitions at multi-megabar pressures, first from the ambient fcc phase to hcp at around 200 GPa, then to bcc at around 320 GPa. Previous static measurements in a diamond-anvil cell have detected the hcp phase above 200 GPa along the room-temperature isentherm. Recent laser-based dynamic compression experiments have observed both the hcp and bcc phases using X-ray diffraction. Here we present high-accuracy velocity waveform data taken on pure and alloy aluminum materials at the Z Machine under shockless compression with 200-ns rise-time to 400 GPa using copper electrodes and lithium-fluoride windows. These are compared to recent EOS tables developed at Los Alamos National Laboratory, to our own results from diffusion quantum Monte-Carlo calculations, and to multi-phase EOS models with phase-transition kinetics. We find clear evidence of a fast transition around 200 GPa as expected, and a possible suggestion of a slower transition at higher pressure. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE AC04-94AL85000.

  10. Analysis of surface contaminants on beryllium and aluminum windows

    International Nuclear Information System (INIS)

    Gmur, N.F.

    1987-06-01

    An effort has been made to document the types of contamination which form on beryllium window surfaces due to interaction with a synchrotron radiation beam. Beryllium windows contaminated in a variety of ways (exposure to water and air) exhibited surface powders, gels, crystals and liquid droplets. These contaminants were analyzed by electron diffraction, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy and wet chemical methods. Materials found on window surfaces include beryllium oxide, amorphous carbon, cuprous oxide, metallic copper and nitric acid. Aluminum window surface contaminants were also examined

  11. Analysis of the Chip Geometry in Dry Machining of Aeronautical Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Francisco Javier Trujillo Vilches

    2017-01-01

    Full Text Available Aluminum alloys are widely used in the manufacturing of structural parts for aircraft, frequently in combination with other materials such as CFRP (Carbon Fiber Reinforced Polymer, to form FML (Fiber Metal Laminates structures (CFRP/Al. The dry machining of these structures presents several problems, some of which are related to chip evacuation, either when machining aluminum alloys as an isotropic material, or during hybridization with composites. In this work, a study of the way in which cutting parameters influence the chip morphology in the dry machining of UNS A97075-T6 (Al-Zn and UNS A92024-T3 (Al-Cu alloys, is performed. Thus, different geometric parameters of the chip morphology have been obtained, and their evolution with feed has been analysed. Finally, the different relationships which occur between these geometric parameters and feed, have been obtained. These relationships allow a prediction of the evolution of some of the geometric parameters of the chip, as a function of feed.

  12. Effect of Equal Channel Angular Pressing on the Surface Roughness of Solid State Recycled Aluminum Alloy 6061 Chips

    Directory of Open Access Journals (Sweden)

    Adel Taha Abbas

    2017-01-01

    Full Text Available Solid state recycling through hot extrusion is a promising technique to recycle machining chips without remelting. Furthermore, equal channel angular pressing (ECAP technique coupled with the extruded recycled billet is introduced to enhance the mechanical properties of recycled samples. In this paper, the surface roughness of solid state recycled aluminum alloy 6061 turning chips was investigated. Aluminum chips were cold compacted and hot extruded under an extrusion ratio (ER of 5.2 at an extrusion temperature (ET of 425°C. In order to improve the properties of the extruded samples, they were subjected to ECAP up to three passes at room temperature using an ECAP die with a channel die angle (Φ of 90°. Surface roughness (Ra and Rz of the processed recycled billets machined by turning was investigated. Box-Behnken experimental design was used to investigate the effect of three machining parameters (cutting speed, feed rate, and depth of cut on the surface roughness of the machined specimens for four materials conditions, namely, extruded billet and postextrusion ECAP processed billets to one, two, and three passes. Quadratic models were developed to relate the machining parameters to surface roughness, and a multiobjective optimization scheme was conducted to maximize material removal rate while maintaining the roughness below a preset practical value.

  13. Advances on aluminum first-surface solar reflectors

    Science.gov (United States)

    Almanza, Rafael; Chen, Jiefeng; Mazari, Marcos

    1992-11-01

    Aluminum first surface mirrors have some advantages over second surface mirrors as has been discussed. At this stage of development some advantages are obtained: the first advantage was using two electron guns, one for aluminum evaporation permitting us to eliminate or to minimize the pinholes and the other to allow the evaporation of SiO without any mirror contamination as it was before due to the air when the chamber was opened to introduce the SiO, despite having only one e-gun in the laboratory. The second advantage was a better adherence between the aluminum film and the Si2O3, this last substance obtained with an oxidation of SiO with some oxygen inside the evaporation chamber (10-4 Torr). This improvement was due to the use of two e-guns that permit us not to open the chamber. These mirrors are actually under test in the environmental chamber for accelerated weather evaluations. One important aspect is the cleaning of the glass substrate. The chromic mixture cleaning is one of the most effective.

  14. Laser Surface Alloying of Aluminum for Improving Acid Corrosion Resistance

    Science.gov (United States)

    Jiru, Woldetinsay Gutu; Sankar, Mamilla Ravi; Dixit, Uday Shanker

    2018-04-01

    In the present study, laser surface alloying of aluminum with magnesium, manganese, titanium and zinc, respectively, was carried out to improve acid corrosion resistance. Laser surface alloying was conducted using 1600 and 1800 W power source using CO2 laser. Acid corrosion resistance was tested by dipping the samples in a solution of 2.5% H2SO4 for 200 h. The weight loss due to acid corrosion was reduced by 55% for AlTi, 41% for AlMg alloy, 36% for AlZn and 22% for AlMn alloy. Laser surface alloyed samples offered greater corrosion resistance than the aluminum substrate. It was observed that localized pitting corrosion was the major factor to damage the surface when exposed for a long time. The hardness after laser surface alloying was increased by a factor of 8.7, 3.4, 2.7 and 2 by alloying with Mn, Mg, Ti and Zn, respectively. After corrosion test, hardness was reduced by 51% for AlTi sample, 40% for AlMg sample, 41.4% for AlMn sample and 33% for AlZn sample.

  15. Water and oil wettability of anodized 6016 aluminum alloy surface

    Science.gov (United States)

    Rodrigues, S. P.; Alves, C. F. Almeida; Cavaleiro, A.; Carvalho, S.

    2017-11-01

    This paper reports on the control of wettability behaviour of a 6000 series aluminum (Al) alloy surface (Al6016-T4), which is widely used in the automotive and aerospace industries. In order to induce the surface micro-nanostructuring of the surface, a combination of prior mechanical polishing steps followed by anodization process with different conditions was used. The surface polishing with sandpaper grit size 1000 promoted aligned grooves on the surface leading to static water contact angle (WCA) of 91° and oil (α-bromonaphthalene) contact angle (OCA) of 32°, indicating a slightly hydrophobic and oleophilic character. H2SO4 and H3PO4 acid electrolytes were used to grow aluminum oxide layers (Al2O3) by anodization, working at 15 V/18° C and 100 V/0 °C, respectively, in one or two-steps configuration. Overall, the anodization results showed that the structured Al surfaces were hydrophilic and oleophilic-like with both WCA and OCA below 90°. The one-step configuration led to a dimple-shaped Al alloy surface with small diameter of around 31 nm, in case of H2SO4, and with larger diameters of around 223 nm in case of H3PO4. The larger dimples achieved with H3PO4 electrolyte allowed to reach a slight hydrophobic surface. The thicker porous Al oxide layers, produced by anodization in two-step configuration, revealed that the liquids can penetrate easily inside the non-ordered porous structures and, thus, the surface wettability tended to superhydrophilic and superoleophilic character (CA OCA. This inversion in favour of the hydrophilic-oleophobic surface behaviour is of great interest either for lubrication of mechanical components or in water-oil separation process.

  16. A new, bright and hard aluminum surface produced by anodization

    Science.gov (United States)

    Hou, Fengyan; Hu, Bo; Tay, See Leng; Wang, Yuxin; Xiong, Chao; Gao, Wei

    2017-07-01

    Anodized aluminum (Al) and Al alloys have a wide range of applications. However, certain anodized finishings have relatively low hardness, dull appearance and/or poor corrosion resistance, which limited their applications. In this research, Al was first electropolished in a phosphoric acid-based solution, then anodized in a sulfuric acid-based solution under controlled processing parameters. The anodized specimen was then sealed by two-step sealing method. A systematic study including microstructure, surface morphology, hardness and corrosion resistance of these anodized films has been conducted. Results show that the hardness of this new anodized film was increased by a factor of 10 compared with the pure Al metal. Salt spray corrosion testing also demonstrated the greatly improved corrosion resistance. Unlike the traditional hard anodized Al which presents a dull-colored surface, this newly developed anodized Al alloy possesses a very bright and shiny surface with good hardness and corrosion resistance.

  17. Machinability of zinc-aluminum alloy5; zamzk5; alloy produced by powder metallurgy

    International Nuclear Information System (INIS)

    Adnan, I.O.; Momani, M.A.A.

    2007-01-01

    Powder metallurgy process (P/M) is repeatedly reported as a near-net or net-shape manufacturing process with the ability of producing parts of complicated or intricate shapes with high required dimensional accuracy and high surface quality. However, some finishing and machining operations are sometimes necessary and must be done to meet dimensional tolerances or accommodate design features that can be achieved during compaction such as transverse holes, undercuts and threads. Therefore, it is necessary to study the machinability of P/M products. ZAMAK5 alloy is widely used in engineering applications in the automobile industry, particularly in the manufacturing of bushes and recently self -lubricated bearings which are manufactured by the P/M process. Therefore it is anticipated that studying the machinability of this alloy as produced by the powder metallurgy process is worthwhile investigating. In this paper, the machinability of ZAMAK5, alloy produced by powder metallurgy, under different cutting conditions of speed, depth of cut and feed rate is carried out. Surface roughness was used as a criterion for assessing machinability at the different conditions. It was found that specimens compacted at 475 MPa and having 1% addition of zinc stearates as a binder and lubricant gave better surface quality than those produced at 550 MPa compacting pressure,whereas at 1.5% addition of zinc stearates produced worse surface quality (i.e. Higher surface roughness than in case of 475 MPa compacting pressure). On the whole, the results of the experimental work revealed that the surface roughness at the different cutting conditions remained within the accepted level in industry, less than 2 microns. (author)

  18. X-ray evaluation of residual stress distributions within surface machined layer generated by surface machining and sequential welding

    International Nuclear Information System (INIS)

    Taniguchi, Yuu; Okano, Shigetaka; Mochizuki, Masahito

    2017-01-01

    The excessive tensile residual stress generated by welding after surface machining may be an important factor to cause stress corrosion cracking (SCC) in nuclear power plants. Therefore we need to understand and control the residual stress distribution appropriately. In this study, residual stress distributions within surface machined layer generated by surface machining and sequential welding were evaluated by X-ray diffraction method. Depth directional distributions were also investigated by electrolytic polishing. In addition, to consider the effect of work hardened layer on the residual stress distributions, we also measured full width at half maximum (FWHM) obtained from X-ray diffraction. Testing material was a low-carbon austenitic stainless steel type SUS316L. Test specimens were prepared by surface machining with different cutting conditions. Then, bead-on-plate welding under the same welding condition was carried out on the test specimens with different surface machined layer. As a result, the tensile residual stress generated by surface machining increased with increasing cutting speed and showed nearly uniform distributions on the surface. Furthermore, the tensile residual stress drastically decreased with increasing measurement depth within surface machined layer. Then, the residual stress approached 0 MPa after the compressive value showed. FWHM also decreased drastically with increasing measurement depth and almost constant value from a certain depth, which was almost equal regardless of the machining condition, within surface machined layer in all specimens. After welding, the transverse distribution of the longitudinal residual stress varied in the area apart from the weld center according to machining conditions and had a maximum value in heat affected zone. The magnitude of the maximum residual stress was almost equal regardless of the machining condition and decreased with increasing measurement depth within surface machined layer. Finally, the

  19. Improved Interfacial Bonding in Magnesium/Aluminum Overcasting Systems by Aluminum Surface Treatments

    Science.gov (United States)

    Zhang, Hui; Chen, Yiqing; Luo, Alan A.

    2014-12-01

    "Overcasting" technique is used to produce bimetallic magnesium/aluminum (Mg/Al) structures where lightweight Mg can be cast onto solid Al substrates. An inherent difficulty in creating strong Mg/Al interfacial bonding is the natural oxide film on the solid Al surfaces, which reduces the wettability between molten Mg and Al substrates during the casting process. In the paper, an "electropolishing + anodizing" surface treatment has been developed to disrupt the oxide film on a dilute Al-0.08 wt pct Ga alloy, improving the metallurgical bonding between molten Mg and Al substrates in the bimetallic experiments carried out in a high-vacuum test apparatus. The test results provided valuable information of the interfacial phenomena of the Mg/Al bimetallic samples. The results show significantly improved metallurgical bonding in the bimetallic samples with "electropolishing + anodizing" surface treatment and Ga alloying. It is recommended to adjust the pre-heating temperature and time of the Al substrates and the Mg melt temperature to control the interfacial reactions for optimum interfacial properties in the actual overcasting processes.

  20. Surface mining machines problems of maintenance and modernization

    CERN Document Server

    Rusiński, Eugeniusz; Moczko, Przemysław; Pietrusiak, Damian

    2017-01-01

    This unique volume imparts practical information on the operation, maintenance, and modernization of heavy performance machines such as lignite mine machines, bucket wheel excavators, and spreaders. Problems of large scale machines (mega machines) are highly specific and not well recognized in the common mechanical engineering environment. Prof. Rusiński and his co-authors identify solutions that increase the durability of these machines as well as discuss methods of failure analysis and technical condition assessment procedures. "Surface Mining Machines: Problems in Maintenance and Modernization" stands as a much-needed guidebook for engineers facing the particular challenges of heavy performance machines and offers a distinct and interesting demonstration of scale-up issues for researchers and scientists from across the fields of machine design and mechanical engineering.

  1. Effect of the Machined Surfaces of AISI 4337 Steel to Cutting Conditions on Dry Machining Lathe

    Science.gov (United States)

    Rahim, Robbi; Napid, Suhardi; Hasibuan, Abdurrozzaq; Rahmah Sibuea, Siti; Yusmartato, Y.

    2018-04-01

    The objective of the research is to obtain a cutting condition which has a good chance of realizing dry machining concept on AISI 4337 steel material by studying surface roughness, microstructure and hardness of machining surface. The data generated from the experiment were then processed and analyzed using the standard Taguchi method L9 (34) orthogonal array. Testing of dry and wet machining used surface test and micro hardness test for each of 27 test specimens. The machining results of the experiments showed that average surface roughness (Raavg) was obtained at optimum cutting conditions when VB 0.1 μm, 0.3 μm and 0.6 μm respectively 1.467 μm, 2.133 μm and 2,800 μm fo r dry machining while which was carried out by wet machining the results obtained were 1,833 μm, 2,667 μm and 3,000 μm. It can be concluded that dry machining provides better surface quality of machinery results than wet machining. Therefore, dry machining is a good choice that may be realized in the manufacturing and automotive industries.

  2. Empirical model for estimating the surface roughness of machined ...

    African Journals Online (AJOL)

    Empirical model for estimating the surface roughness of machined ... as well as surface finish is one of the most critical quality measure in mechanical products. ... various cutting speed have been developed using regression analysis software.

  3. Learning surface molecular structures via machine vision

    Science.gov (United States)

    Ziatdinov, Maxim; Maksov, Artem; Kalinin, Sergei V.

    2017-08-01

    Recent advances in high resolution scanning transmission electron and scanning probe microscopies have allowed researchers to perform measurements of materials structural parameters and functional properties in real space with a picometre precision. In many technologically relevant atomic and/or molecular systems, however, the information of interest is distributed spatially in a non-uniform manner and may have a complex multi-dimensional nature. One of the critical issues, therefore, lies in being able to accurately identify (`read out') all the individual building blocks in different atomic/molecular architectures, as well as more complex patterns that these blocks may form, on a scale of hundreds and thousands of individual atomic/molecular units. Here we employ machine vision to read and recognize complex molecular assemblies on surfaces. Specifically, we combine Markov random field model and convolutional neural networks to classify structural and rotational states of all individual building blocks in molecular assembly on the metallic surface visualized in high-resolution scanning tunneling microscopy measurements. We show how the obtained full decoding of the system allows us to directly construct a pair density function—a centerpiece in analysis of disorder-property relationship paradigm—as well as to analyze spatial correlations between multiple order parameters at the nanoscale, and elucidate reaction pathway involving molecular conformation changes. The method represents a significant shift in our way of analyzing atomic and/or molecular resolved microscopic images and can be applied to variety of other microscopic measurements of structural, electronic, and magnetic orders in different condensed matter systems.

  4. Mechanical properties and microstructures of 1100 aluminum subjected to dry machining

    International Nuclear Information System (INIS)

    Ni, H.; Elmadagli, M.; Alpas, A.T.

    2004-01-01

    Commercial purity 1100 aluminum samples with an initial grain size of 4.6 μm were subjected to dry orthogonal cutting, i.e., without using cutting fluid. The strain distributions in the deformed material ahead of the cutting tool tip were estimated using a metallographic method based on the observation of shear angles. Local flow stress values were estimated using microhardness measurements. Deformation structures developed in the material ahead of the tool tip were investigated at four different locations using transmission electron microscopy (TEM). The microstructure in the primary deformation zone (PDZ) was characterized by elongated subgrains, extending in the direction of the strain gradient. The average thickness of the subgrains was 380 nm and their width was 730 nm. The hardness of the PDZ was 80 kg/mm 2 , which represented an increase of 80% from the initial hardness. The strains in the machined chips (MC) reached a high value of 2.3. The corresponding microstructure consisted of a mixture of elongated subgrains with dimensions similar to those observed in the PDZ, and recrystallized equiaxed grains with diameters ranging between 25 and 75 nm. This was accompanied with an 8% decrease in the hardness of the MC compared to that of the PDZ. Grain growth occurred in the secondary deformation zone (SDZ) resulting in large equiaxed grains of 1.2 μm in diameter. The use of cooling fluid during machining restricted grain growth in the SDZ by limiting the grain size to 360 nm

  5. A simple surface treatment and characterization of AA 6061 aluminum alloy surface for adhesive bonding applications

    International Nuclear Information System (INIS)

    Saleema, N.; Sarkar, D.K.; Paynter, R.W.; Gallant, D.; Eskandarian, M.

    2012-01-01

    Highlights: ► A very simple surface treatment method to achieve excellent and durable aluminum adhesive bonding. ► Our method involves simple immersion of aluminum in very dilute NaOH solution at room temperature with no involvement of strong acids or multiple procedures. ► Surface analysis via various surface characterization techniques showed morphological and chemical modifications favorable for obtaining highly durable bond strengths on the treated surface. ► Safe, economical, reproducible and simple method, easily applicable in industries. - Abstract: Structural adhesive bonding of aluminum is widely used in aircraft and automotive industries. It has been widely noted that surface preparation of aluminum surfaces prior to adhesive bonding plays a significant role in improving the strength of the adhesive bond. Surface cleanliness, surface roughness, surface wettability and surface chemistry are controlled primarily by proper surface treatment methods. In this study, we have employed a very simple technique influencing all these criteria by simply immersing aluminum substrates in a very dilute solution of sodium hydroxide (NaOH) and we have studied the effect of varying the treatment period on the adhesive bonding characteristics. A bi-component epoxy adhesive was used to join the treated surfaces and the bond strengths were evaluated via single lap shear (SLS) tests in pristine as well as degraded conditions. Surface morphology, chemistry, crystalline nature and wettability of the NaOH treated surfaces were characterized using various surface analytical tools such as scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), optical profilometry, infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and contact angle goniometry. Excellent adhesion characteristics with complete cohesive failure of the adhesive were encountered on the NaOH treated surfaces that are comparable to the benchmark

  6. Environmental performance assessment of a company of aluminum surface treatment

    Directory of Open Access Journals (Sweden)

    Susan Catieri Ramalho

    2013-08-01

    Full Text Available The purpose of this article was to evaluate the environmental performance of a medium-sized company that provides services for surface treatment of aluminum. The treatment is known as anodizing. The research method was qualitative numerical modeling. The environmental performance of the company was organized into five constructs: atmosphere, wastewater, energy and natural resources, solid waste, and legislation and management. Nineteen indicators were chosen to explain the five constructs. Ten employees of the company prioritized the constructs and evaluated the situation of the indicators by means of a scale of assessment. By means of a mathematical model, the general performance of the environmental operation was calculated at 74.5% of the maximum possible. The indicators that most contributed to the performance not to reach 100% were consumption of electricity and water consumption. The construct of worse performance was natural and energy resources. These are the priorities for future environmental improvement actions that the company may promote.

  7. Vibratory Machining Effect on the Properties of the Aaluminum Alloys Surface

    Directory of Open Access Journals (Sweden)

    Bańkowski D.

    2017-12-01

    Full Text Available The article presents an example of finishing treatment for aluminum alloys with the use of vibration machining, with loose abrasive media in a closed tumbler. For the analysis of selected properties of the surface layer prepared flat samples of aluminum alloy PA6/2017 in the state after recrystallization. The samples in the first stage were subjected to a treatment of deburring using ceramic media. In a second step polishing process performed with a strengthening metal media. In addition, for comparative purposes was considered. only the case of metal polishing. The prepared samples were subjected to hardness tests and a tangential tensile test. As a result of finishing with vibratory machining, it was possible to remove burrs, flash, rounding sharp edges, smoothing and lightening the surface of objects made. The basic parameters of the surface geometry were obtained using the Talysurf CCI Lite - Taylor Hobson optical profiler. As a result of the tests it can be stated that the greatest reduction of surface roughness and mass loss occurs in the first minutes of the process. Mechanical tests have shown that the most advantageous high values of tensile strength and hardness are obtained with two-stage vibration treatment, - combination of deburring and polishing. Moreover the use of metal media resulted in the strengthening of the surface by pressure deburring with metal media.

  8. Mirror-finished superhydrophobic aluminum surfaces modified by anodic alumina nanofibers and self-assembled monolayers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2018-05-01

    We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

  9. Engineered Surface Properties of Porous Tungsten from Cryogenic Machining

    Science.gov (United States)

    Schoop, Julius Malte

    Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is investigated as a substitutionary process for the current plastic infiltration process. Along with significant reductions in cycle time and resource use, surface quality of cryogenically machined un-infiltrated (as-sintered) porous tungsten has been shown to significantly outperform dry machining. The present study is focused on examining the relationship between machining parameters and cooling condition on the as-machined surface integrity of porous tungsten. The effects of cryogenic pre-cooling, rake angle, cutting speed, depth of cut and feed are all taken into consideration with respect to machining-induced surface morphology. Cermet and Polycrystalline diamond (PCD) cutting tools are used to develop high performance cryogenic machining of porous tungsten. Dry and pre-heated machining were investigated as a means to allow for ductile mode machining, yet severe tool-wear and undesirable smearing limited the feasibility of these approaches. By using modified PCD cutting tools, high speed machining of porous tungsten at cutting speeds up to 400 m/min is achieved for the first time. Beyond a critical speed, brittle fracture and built-up edge are eliminated as the result of a brittle to ductile transition. A model of critical chip thickness ( hc ) effects based on cutting

  10. Technology of magnetic abrasive finishing in machining of difficult-to-machine alloy complex surface

    Directory of Open Access Journals (Sweden)

    Fujian MA

    2016-10-01

    Full Text Available The technology of magnetic abrasive finishing is one of the important finishing technologies. Combining with low-frequency vibration and ultrasonic vibration, it can attain higher precision, quality and efficiency. The characteristics and the related current research of magnetic abrasive finishing, vibration assisted magnetic abrasive finishing and ultrasonic assisted magnetic abrasive finishing are introduced. According to the characteristics of the difficult-to-machine alloy's complex surface, the important problems for further study are presented to realize the finishing of complex surface with the technology of magnetic abrasive finishing, such as increasing the machining efficiency by enhancing the magnetic flux density of machining gap and compounding of magnetic energy and others, establishing of the control function during machining and the process planning method for magnetic abrasive finishing of complex surface under the space geometry restraint of complex surface on magnetic pole, etc.

  11. EDM machinability of SiCw/Al composites

    Science.gov (United States)

    Ramulu, M.; Taya, M.

    1989-01-01

    Machinability of high temperature composites was investigated. Target materials, 15 and 25 vol pct SiC whisker-2124 aluminum composites, were machined by electrodischarge sinker machining and diamond saw. The machined surfaces of these metal matrix composites were examined by SEM and profilometry to determine the surface finish. Microhardness measurements were also performed on the as-machined composites.

  12. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  13. Phosphonate self-assembled monolayers on aluminum surfaces

    International Nuclear Information System (INIS)

    Hoque, E.; DeRose, J.A.; Hoffmann, P.; Mathieu, H.J.; Bhushan, B.; Cichomski, M.

    2006-01-01

    Substrates of aluminum (Al) deposited by physical vapor deposition onto Si substrates and then chemically reacted with perfluorodecylphosphonic acid (PFDP/Al/Si), decylphosphonic acid (DP/Al/Si), and octadecylphosphonic acid (ODP/Al/Si) were studied by x-ray photoelectron spectroscopy (XPS), contact angle measurements, atomic force microscopy (AFM), and friction force microscopy, a derivative of AFM, to characterize their surface chemical composition, roughness, and micro-/nanotribological properties. XPS analysis confirmed the presence of perfluorinated and nonperfluorinated alkylphosphonate molecules on the PFDP/Al/Si, DP/Al/Si, and ODP/Al/Si. The sessile drop static contact angle of pure water on PFDP/Al/Si was typically more than 130 deg. and on DP/Al/Si and ODP/Al/Si typically more than 125 deg. indicating that all phosphonic acid reacted Al/Si samples were very hydrophobic. The surface roughness for PFDP/Al/Si, DP/Al/Si, ODP/Al/Si, and bare Al/Si was approximately 35 nm as determined by AFM. The surface energy for PFDP/Al/Si was determined to be approximately 11 mN/m by the Zisman plot method compared to 21 and 20 mN/m for DP/Al/Si and ODP/Al/Si, respectively. Tribology involves the measure of lateral forces due to friction and adhesion between two surfaces. Friction, adhesion, and wear play important roles in the performance of micro-/nanoelectromechanical systems. PFDP/Al/Si gave the lowest adhesion and coefficient of friction values while bare Al/Si gave the highest. The adhesion and coefficient of friction values for DP/Al/Si and ODP/Al/Si were comparable

  14. 40 CFR 63.5743 - What standards must I meet for aluminum recreational boat surface coating operations?

    Science.gov (United States)

    2010-07-01

    ... recreational boat surface coating operations? 63.5743 Section 63.5743 Protection of Environment ENVIRONMENTAL... Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5743 What standards must I meet for aluminum recreational boat surface coating operations? (a) For aluminum wipedown solvent...

  15. Generation of gear tooth surfaces by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.

    1994-01-01

    This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

  16. Superhydrophilicity of a nanofiber-covered aluminum surface fabricated via pyrophosphoric acid anodizing

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2016-12-01

    A superhydrophilic aluminum surface covered by numerous alumina nanofibers was fabricated via pyrophosphoric acid anodizing. High-density anodic alumina nanofibers grow on the bottom of a honeycomb oxide via anodizing in concentrated pyrophosphoric acid. The water contact angle on the nanofiber-covered aluminum surface decreased with time after a 4 μL droplet was placed on the surface, and a superhydrophilic behavior with a contact angle measuring 2.2° was observed within 2 s; this contact angle is considerably lower than those observed for electropolished and porous alumina-covered aluminum surfaces. There was no dependence of the superhydrophilicity on the density of alumina nanofibers fabricated via different constant voltage anodizing conditions. The superhydrophilic property of the surface covered by anodic alumina nanofibers was maintained during an exposure test for 359 h. The quick-drying and snow-sliding behaviors of the superhydrophilic aluminum covered with anodic alumina nanofibers were demonstrated.

  17. The Impact Of Surface Shape Of Chip-Breaker On Machined Surface

    Science.gov (United States)

    Šajgalík, Michal; Czán, Andrej; Martinček, Juraj; Varga, Daniel; Hemžský, Pavel; Pitela, David

    2015-12-01

    Machined surface is one of the most used indicators of workpiece quality. But machined surface is influenced by several factors such as cutting parameters, cutting material, shape of cutting tool or cutting insert, micro-structure of machined material and other known as technological parameters. By improving of these parameters, we can improve machined surface. In the machining, there is important to identify the characteristics of main product of these processes - workpiece, but also the byproduct - the chip. Size and shape of chip has impact on lifetime of cutting tools and its inappropriate form can influence the machine functionality and lifetime, too. This article deals with elimination of long chip created when machining of shaft in automotive industry and with impact of shape of chip-breaker on shape of chip in various cutting conditions based on production requirements.

  18. Nano-TiO{sub 2} coatings on aluminum surfaces by aerosol flame synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Liberini, Mariacira; De Falco, Gianluigi; Scherillo, Fabio; Astarita, Antonello [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy); Commodo, Mario; Minutolo, Patrizia [Istituto di Ricerche sulla Combustione, CNR, Napoli 80125 (Italy); D' Anna, Andrea, E-mail: anddanna@unina.it [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy); Squillace, Antonino [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli Federico II, Napoli 80125 (Italy)

    2016-06-30

    Aluminum alloys are widely used in the aeronautic industry for their high mechanical properties; however, because they are very sensitive to corrosion, surface treatments are often required. TiO{sub 2} has excellent resistance to oxidation and it is often used to improve the corrosion resistance of aluminum surfaces. Several coating procedures have been proposed over the years, which are in some cases expensive in terms of production time and amount of deposited material. Moreover, they can damage aluminum alloys if thermal treatments are required. In this paper, a one-step method for the coating of aluminum surfaces with titania nanoparticles is presented. Narrowly sized, TiO{sub 2} nanoparticles are synthesized by flame aerosol and directly deposited by thermophoresis onto cold plates of aluminum AA2024. Submicron coatings of different thicknesses are obtained from two flame synthesis conditions by varying the total deposition time. A fuel-lean synthesis condition was used to produce 3.5 nm pure anatase nanoparticles, while a mixture of rutile and anatase nanoparticles having 22 nm diameter — rutile being the predominant phase —, was synthesized in a fuel-rich condition. Scanning electron microscopy is used to characterize morphology of titania films, while coating thickness is measured by confocal microscopy measurements. Electrochemical impedance spectroscopy is used to evaluate corrosion resistance of coated aluminum substrates. Results show an improvement of the electrochemical behavior of titania coated surfaces as compared to pristine aluminum surfaces. The best results are obtained by covering the substrates with 3.5 nm anatase-phase nanoparticles and with lower deposition times, that assure a uniform surface coating. - Highlights: • Nanosized TiO{sub 2} particles produced by aerosol flame synthesis • Coatings of aluminum substrates with TiO{sub 2} nanoparticles by thermophoretic deposition in flames • Thickness measurement by confocal microscopy

  19. Nano-TiO_2 coatings on aluminum surfaces by aerosol flame synthesis

    International Nuclear Information System (INIS)

    Liberini, Mariacira; De Falco, Gianluigi; Scherillo, Fabio; Astarita, Antonello; Commodo, Mario; Minutolo, Patrizia; D'Anna, Andrea; Squillace, Antonino

    2016-01-01

    Aluminum alloys are widely used in the aeronautic industry for their high mechanical properties; however, because they are very sensitive to corrosion, surface treatments are often required. TiO_2 has excellent resistance to oxidation and it is often used to improve the corrosion resistance of aluminum surfaces. Several coating procedures have been proposed over the years, which are in some cases expensive in terms of production time and amount of deposited material. Moreover, they can damage aluminum alloys if thermal treatments are required. In this paper, a one-step method for the coating of aluminum surfaces with titania nanoparticles is presented. Narrowly sized, TiO_2 nanoparticles are synthesized by flame aerosol and directly deposited by thermophoresis onto cold plates of aluminum AA2024. Submicron coatings of different thicknesses are obtained from two flame synthesis conditions by varying the total deposition time. A fuel-lean synthesis condition was used to produce 3.5 nm pure anatase nanoparticles, while a mixture of rutile and anatase nanoparticles having 22 nm diameter — rutile being the predominant phase —, was synthesized in a fuel-rich condition. Scanning electron microscopy is used to characterize morphology of titania films, while coating thickness is measured by confocal microscopy measurements. Electrochemical impedance spectroscopy is used to evaluate corrosion resistance of coated aluminum substrates. Results show an improvement of the electrochemical behavior of titania coated surfaces as compared to pristine aluminum surfaces. The best results are obtained by covering the substrates with 3.5 nm anatase-phase nanoparticles and with lower deposition times, that assure a uniform surface coating. - Highlights: • Nanosized TiO_2 particles produced by aerosol flame synthesis • Coatings of aluminum substrates with TiO_2 nanoparticles by thermophoretic deposition in flames • Thickness measurement by confocal microscopy • Improvement of

  20. Degradation of Perfluorinated Ether Lubricants on Pure Aluminum Surfaces: Semiempirical Quantum Chemical Modeling

    Science.gov (United States)

    Slaby, Scott M.; Ewing, David W.; Zehe, Michael J.

    1997-01-01

    The AM1 semiempirical quantum chemical method was used to model the interaction of perfluoroethers with aluminum surfaces. Perfluorodimethoxymethane and perfluorodimethyl ether were studied interacting with aluminum surfaces, which were modeled by a five-atom cluster and a nine-atom cluster. Interactions were studied for edge (high index) sites and top (low index) sites of the clusters. Both dissociative binding and nondissociative binding were found, with dissociative binding being stronger. The two different ethers bound and dissociated on the clusters in different ways: perfluorodimethoxymethane through its oxygen atoms, but perfluorodimethyl ether through its fluorine atoms. The acetal linkage of perfluorodimeth-oxymethane was the key structural feature of this molecule in its binding and dissociation on the aluminum surface models. The high-index sites of the clusters caused the dissociation of both ethers. These results are consistent with the experimental observation that perfluorinated ethers decompose in contact with sputtered aluminum surfaces.

  1. Environmentally Benign Sol-Gel Surface Treatment for Aluminum Bonding Applications

    National Research Council Canada - National Science Library

    Osborne, Joseph

    1996-01-01

    A surface treatment process for aluminum using sol-gel chemistry has been developed that produces strong adhesive bonds without the rinse water requirements of traditional anodizing or etching processes...

  2. Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2007-06-01

    Full Text Available Polypyrrole (PPy films were galvanostatically deposited on 99.9 wt. (% aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments.

  3. Optimization of Coolant Technique Conditions for Machining A319 Aluminium Alloy Using Response Surface Method (RSM)

    Science.gov (United States)

    Zainal Ariffin, S.; Razlan, A.; Ali, M. Mohd; Efendee, A. M.; Rahman, M. M.

    2018-03-01

    Background/Objectives: The paper discusses about the optimum cutting parameters with coolant techniques condition (1.0 mm nozzle orifice, wet and dry) to optimize surface roughness, temperature and tool wear in the machining process based on the selected setting parameters. The selected cutting parameters for this study were the cutting speed, feed rate, depth of cut and coolant techniques condition. Methods/Statistical Analysis Experiments were conducted and investigated based on Design of Experiment (DOE) with Response Surface Method. The research of the aggressive machining process on aluminum alloy (A319) for automotive applications is an effort to understand the machining concept, which widely used in a variety of manufacturing industries especially in the automotive industry. Findings: The results show that the dominant failure mode is the surface roughness, temperature and tool wear when using 1.0 mm nozzle orifice, increases during machining and also can be alternative minimize built up edge of the A319. The exploration for surface roughness, productivity and the optimization of cutting speed in the technical and commercial aspects of the manufacturing processes of A319 are discussed in automotive components industries for further work Applications/Improvements: The research result also beneficial in minimizing the costs incurred and improving productivity of manufacturing firms. According to the mathematical model and equations, generated by CCD based RSM, experiments were performed and cutting coolant condition technique using size nozzle can reduces tool wear, surface roughness and temperature was obtained. Results have been analyzed and optimization has been carried out for selecting cutting parameters, shows that the effectiveness and efficiency of the system can be identified and helps to solve potential problems.

  4. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.F. [Xi' an High-technology Institute, Xi' an 710025 (China)], E-mail: xiaofang_liu@263.net; Wu, Q.Y.; Wang, H.G. [Xi' an High-technology Institute, Xi' an 710025 (China)

    2008-06-15

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion.

  5. Effect of surface modifications and environment on the interfacial adhesion of polymer/aluminum alloy

    International Nuclear Information System (INIS)

    Liu, X.F.; Wu, Q.Y.; Wang, H.G.

    2008-01-01

    This work investigates the influence of surface modifications and environmental conditions on the interfacial adhesion of epoxy resin films on a 6016 aluminum alloy, as measured by peeling experiments. The alloy surfaces were pretreated with an etching solution, and then modified, respectively, with aminopropyl silane solution, aminopropyl phosphonate solution, and hexamethyldisiloxane plasma. The modified surfaces were examined by scanning electron microscopy and their roughness was quantified by a fractal index. The peeling experiments show that the interfacial adhesion of epoxy on the aluminum alloy mainly results from the chemical and mechanical characteristics of the material surface. Environmental factors such as humidity can also weaken interfacial adhesion

  6. Investigation on Surface Roughness of Inconel 718 in Photochemical Machining

    Directory of Open Access Journals (Sweden)

    Nitin D. Misal

    2017-01-01

    Full Text Available The present work is focused on estimating the optimal machining parameters required for photochemical machining (PCM of an Inconel 718 and effects of these parameters on surface topology. An experimental analysis was carried out to identify optimal values of parameters using ferric chloride (FeCl3 as an etchant. The parameters considered in this analysis are concentration of etchant, etching time, and etchant temperature. The experimental analysis shows that etching performance as well as surface topology improved by appropriate selection of etching process parameters. Temperature of the etchant found to be dominant parameter in the PCM of Inconel 718 for surface roughness. At optimal etching conditions, surface roughness was found to be 0.201 μm.

  7. Manufacturing tungsten monocrystal tubes by electro-spark machining and study of machined surface structure

    International Nuclear Information System (INIS)

    Abdukarimov, Eh.T.; Ismailov, L.R.; Krakhmalev, V.A.; Fershtat, L.N.

    1981-01-01

    A technique to manufacture tubes from tungsten monocrystals with low consumption of electrodes has been developed. Regimes of obtaining deep and through holes of different diameters with the productivity of 1 mm/min and with the minimum deviation from cylindrical shape are worked out using a specially designed electric pulse installation. X-ray and metallographical analyses have shown that as a result of electrospark machining a cold hardened layer is formed up to hundreds micrometers thick, pierced by the network of microcracks. Simultaneous use of electrospark and electrochemical machining permitted to manufacture tubes from tungsten monocrystals with non-distorted monocrystal surface and without a network of microcracks

  8. Molecular dynamic simulations of the high-speed copper nanoparticles collision with the aluminum surface

    Science.gov (United States)

    Pogorelko, V. V.; Mayer, A. E.

    2016-11-01

    With the use of the molecular dynamic simulations, we investigated the effect of the high-speed (500 m/s, 1000 m/s) copper nanoparticle impact on the mechanical properties of an aluminum surface. Dislocation analysis shows that a large number of dislocations are formed in the impact area; the total length of dislocations is determined not only by the speed and size of the incoming copper nanoparticle (kinetic energy of the nanoparticle), but by a temperature of the system as well. The dislocations occupy the whole area of the aluminum single crystal at high kinetic energy of the nanoparticle. With the decrease of the nanoparticle kinetic energy, the dislocation structures are formed in the near-surface layer; formation of the dislocation loops takes place. Temperature rise of the system (aluminum substrate + nanoparticle) reduces the total dislocation length in the single crystal of aluminum; there is deeper penetration of the copper atoms in the aluminum at high temperatures. Average energy of the nanoparticles and room temperature of the system are optimal for production of high-quality layers of copper on the aluminum surface.

  9. Surface Inspection Machine Infrared (SIMIR). Final CRADA report

    Energy Technology Data Exchange (ETDEWEB)

    Powell, G.L. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Neu, J.T.; Beecroft, M. [Surface Optics Corp., San Diego, CA (United States)

    1997-02-28

    This Cooperative Research and Development Agreement was a one year effort to make the surface inspection machine based on diffuse reflectance infrared spectroscopy (Surface Inspection Machine-Infrared, SIMIR), being developed by Surface Optics Corporation, perform to its highest potential as a practical, portable surface inspection machine. The design function of the SIMIR is to inspect metal surfaces for cleanliness (stains). The system is also capable of evaluating graphite-resin systems for cure and heat damage, and for measuring the effects of moisture exposure on lithium hydride, corrosion on uranium metal, and the constituents of and contamination on wood, paper, and fabrics. Over the period of the CRADA, extensive experience with the use of the SIMIR for surface cleanliness measurements have been achieved through collaborations with NASA and the Army. The SIMIR was made available to the AMTEX CRADA for Finish on Yarn where it made a very significant contribution. The SIMIR was the foundation of a Forest Products CRADA that was developed over the time interval of this CRADA. Surface Optics Corporation and the SIMIR have been introduced to the chemical spectroscopy on-line analysis market and have made staffing additions and arrangements for international marketing of the SIMIR as an on-line surface inspection device. LMES has been introduced to a wide range of aerospace applications, the research and fabrication skills of Surface Optics Corporation, has gained extensive experience in the areas of surface cleanliness from collaborations with NASA and the Army, and an extensive introduction to the textile and forest products industries. The SIMIR, marketed as the SOC-400, has filled an important new technology need in the DOE-DP Enhanced Surveillance Program with instruments delivered to or on order by LMES, LANL, LLNL, and Pantex, where extensive collaborations are underway to implement and improve this technology.

  10. Surface Inspection Machine Infrared (SIMIR). Final CRADA report

    International Nuclear Information System (INIS)

    Powell, G.L.; Neu, J.T.; Beecroft, M.

    1997-01-01

    This Cooperative Research and Development Agreement was a one year effort to make the surface inspection machine based on diffuse reflectance infrared spectroscopy (Surface Inspection Machine-Infrared, SIMIR), being developed by Surface Optics Corporation, perform to its highest potential as a practical, portable surface inspection machine. The design function of the SIMIR is to inspect metal surfaces for cleanliness (stains). The system is also capable of evaluating graphite-resin systems for cure and heat damage, and for measuring the effects of moisture exposure on lithium hydride, corrosion on uranium metal, and the constituents of and contamination on wood, paper, and fabrics. Over the period of the CRADA, extensive experience with the use of the SIMIR for surface cleanliness measurements have been achieved through collaborations with NASA and the Army. The SIMIR was made available to the AMTEX CRADA for Finish on Yarn where it made a very significant contribution. The SIMIR was the foundation of a Forest Products CRADA that was developed over the time interval of this CRADA. Surface Optics Corporation and the SIMIR have been introduced to the chemical spectroscopy on-line analysis market and have made staffing additions and arrangements for international marketing of the SIMIR as an on-line surface inspection device. LMES has been introduced to a wide range of aerospace applications, the research and fabrication skills of Surface Optics Corporation, has gained extensive experience in the areas of surface cleanliness from collaborations with NASA and the Army, and an extensive introduction to the textile and forest products industries. The SIMIR, marketed as the SOC-400, has filled an important new technology need in the DOE-DP Enhanced Surveillance Program with instruments delivered to or on order by LMES, LANL, LLNL, and Pantex, where extensive collaborations are underway to implement and improve this technology

  11. An Axial Sliding Test for machine elements surfaces

    DEFF Research Database (Denmark)

    Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

    2012-01-01

    are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

  12. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Science.gov (United States)

    Liu, Wenyong; Luo, Yuting; Sun, Linyu; Wu, Ruomei; Jiang, Haiyun; Liu, Yuejun

    2013-01-01

    We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low surface free energy, the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  13. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wenyong, E-mail: lwy@iccas.ac.cn [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Luo Yuting; Sun Linyu [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Wu Ruomei, E-mail: cailiaodian2004@126.com [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Jiang Haiyun [College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China); Liu Yuejun [Key Laboratory of Advanced Materials and Technology for Packaging, Hunan University of Technology, Zhuzhou 412007 (China); College of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007 (China)

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: Black-Right-Pointing-Pointer Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. Black-Right-Pointing-Pointer Superhydrophobic surfaces with a high water contact angle of 162 Degree-Sign and a low rolling angle of 2 Degree-Sign were obtained. Black-Right-Pointing-Pointer The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162 Degree-Sign and the sliding angle of 2 Degree-Sign was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed

  14. Fabrication of the superhydrophobic surface on aluminum alloy by anodizing and polymeric coating

    International Nuclear Information System (INIS)

    Liu Wenyong; Luo Yuting; Sun Linyu; Wu Ruomei; Jiang Haiyun; Liu Yuejun

    2013-01-01

    Graphical abstract: The hydrophobic surface on aluminum alloy fabricated by anodizing and polymeric coating. Highlights: ► Anodizing and polymeric coating were used to prepare a superhydrophobic surface on aluminum alloy. ► Superhydrophobic surfaces with a high water contact angle of 162° and a low rolling angle of 2° were obtained. ► The method is facile, and the materials are inexpensive, and is expected to be used widely. - Abstract: We reported the preparation of the superhydrophobic surface on aluminum alloy via anodizing and polymeric coating. Both the different anodizing processes and different polymeric coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. The results showed that a good superhydrophobic surface was facilely fabricated by polypropylene (PP) coating after anodizing. The optimum conditions for anodizing were determined by orthogonal experiments. When the concentration of oxalic acid was 10 g/L, the concentration of NaCl was 1.25 g/L, anodization time was 40 min, and anodization current was 0.4 A, the best superhydrophobic surface on aluminum alloy with the contact angle (CA) of 162° and the sliding angle of 2° was obtained. On the other hand, the different polymeric coatings, such as polystyrene (PS), polypropylene (PP) and polypropylene grafting maleic anhydride (PP-g-MAH) were used to coat the aluminum alloy surface after anodizing. The results showed that the superhydrophobicity was most excellent by coating PP, while the duration of the hydrophobic surface was poor. By modifying the surface with the silane coupling agent before PP coating, the duration of the superhydrophobic surface was improved. The morphologies of the superhydrophobic surface were further confirmed by optical microscope (OM) and scanning electron microscope (SEM). Combined with the material of PP with the low

  15. Effect of Aluminum Coating on the Surface Properties of Ti-(~49 at. pct) Ni Alloy

    Science.gov (United States)

    Sinha, Arijit; Khan, Gobinda Gopal; Mondal, Bholanath; Majumdar, Jyotsna Dutta; Chattopadhyay, Partha Protim

    2015-08-01

    Stable porous layer of mixed Al2O3 and TiO2 has been formed on the Ti-(~49 at. pct) Ni alloy surface with an aim to suppress leaching of Ni from the alloy surface in contact with bio-fluid and to enhance the process of osseointegration. Aluminum coating on the Ni-Ti alloy surface prior to the anodization treatment has resulted in enhancement of depth and uniformity of pores. Thermal oxidation of the anodized aluminum-coated Ni-Ti samples has exhibited the formation of Al2O3 and TiO2 phases with dense porous structure. The nanoindentation and nanoscratch measurements have indicated a remarkable improvement in the hardness, wear resistance, and adhesiveness of the porous aluminum-coated Ni-Ti sample after thermal oxidation.

  16. Surface Coating of Plastic Parts for Business Machines (Industrial Surface Coating): New Source Performance Standards (NSPS)

    Science.gov (United States)

    Learn more about the new source performance standards (NSPS) for surface coating of plastic parts for business machines by reading the rule summary and history and finding the code of federal regulations as well as related rules.

  17. On machine surface to the unit event causing residual stress

    International Nuclear Information System (INIS)

    Arunachalama, R.M.; Mannanb, M.A.; Spowageca, A.

    2005-01-01

    Integrity and reduce overall costs. Within the framework of surface integrity investigations, special emphasis is given to the measurement of residual stresses because they contribute directly to premature failure of components. Since the highest residual stresses are to be found in surface layers, these deserve special attention when dealing with dynamically, heavily loaded machine parts such as gas turbine components used in aero engines. Of the many techniques available for the measurement of residual stresses, the most highly developed and widely used non-destructive method is based on X-ray diffraction (XRD). However, it is not possible to use this technique for inspection of all the components, since it is time consuming, complicated as well as expensive. In this paper, a method is being proposed that augments the XRD method but at the same time capable of inspecting all the components. A non-destructive, visual inspection technique has been developed that can correlate the characteristic features on the surface to the unit event causing the residual stress and the type of residual stress generated on the machined surface. Pictures of the machined surfaces have been taken using a digital video microscope at a magnification of 500 and the surface feature correlated to the unit event causing the residual stress. Sharp and well defined long grooves indicate that the plastic deformation is dominated by a mechanical unit event while appearance of streaks and small areas of smeared material indicate that the plastic deformation is dominated by a thermal unit event. These trends have been confirmed by measuring the residual stresses using XRD. The proposed technique is an attempt at establishing a simple methodology that would be useful to industries manufacturing aerospace and other components that require good surface integrity. (Author)

  18. Ester oxidation on an aluminum surface using chemiluminescence

    Science.gov (United States)

    Jones, William R., Jr.; Meador, Michael A.; Morales, Wilfredo

    1986-01-01

    The oxidation characteristics of a pure ester (trimethyolpropane triheptanoate) were studied by using a chemiluminescence technique. Tests were run in a thin film microoxidation apparatus with an aluminum alloy catalyst. Conditions included a pure oxygen atmosphere and a temperature range of 176 to 206 C. Results indicated that oxidation of the ester (containing .001 M diphenylanthracene as an intensifier) was accompanied by emission of light. The maximum intensity of light emission was a function of the amount of ester, the concentration of intensifier, and the test temperature. The induction period, or the time to reach one-half of maximum intensity was inversely proportional to test temperature. Decreases in light emission at the later stages of a test were caused by depletion of the intensifier.

  19. Influence of surface treatment on the biocompatibility of aluminum substrates promising for medical application

    Energy Technology Data Exchange (ETDEWEB)

    Kiradzhiyska, D. D., E-mail: denica.kiradjiiska@gmail.com; Mantcheva, R. D., E-mail: r-manch@abv.bg [Medical University - Plovdiv, Faculty of Pharmacy, Department of Chemical Science15A Vassil Aprilov blvd., 4002 Plovdiv (Bulgaria); Feodorova, Y. N.; Draganov, M. M. [Medical University - Plovdiv, Medical Faculty, Department of Medical Biology, 15A Vassil Aprilov blvd., 4002 Plovdiv (Bulgaria); Girginov, Ch. A. [University of Chemical Technology and Metallurgy -Sofia, Department of Chemical Science, Subdepartment of Physical Chemistry, 8 Kliment Ohridski Blvd. 1756 Sofia (Bulgaria); Viraneva, A. P.; Yovcheva, T. A. [University of Plovdiv “Paisiy Hilendarski”, Faculty of Physics, Department of Experimental Physic, 24 Tsar Assen str., 4000 Plovdiv (Bulgaria)

    2016-03-25

    Materials for medical implants should have suitable mechanical properties, excellent biocompatibility and high corrosion resistance. They should not stimulate allergic and immunologic reactions and should not cause cancer. The use of aluminum as a construction material in implantology is continuously expanding. There are various methods for surface treatment to improve its biocompatibility. In this study aluminum samples anodized in 15% H{sub 2} SO{sub 4} or treated with positive or negative corona discharge were investigated. PDL-cell line of immortalized cells, precursors of periodontal ligament and RAW 264.7 cell line from mouse macrophages are used for the bioassays. The results show that 10 and 20 μm thick oxide film provides better development of the PLD cells, compared to untreated aluminum. Metal surfaces with 10 μm thick oxide film show the best properties in terms of cells vitality, proliferation and growth. Polymer treated but uncharged samples show good results.

  20. Ab-initio study of surface segregation in aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yifa, E-mail: yfqin10s@imr.ac.cn; Wang, Shaoqing

    2017-03-31

    Highlights: • A thorough study of surface segregation energies of 41 elements in Al is performed. • Segregation energies vary periodically with the atomic numbers of impurities. • 41 elements are classified into 3 groups according to the signs of segregation energies. • The results are validated by the surface/total concentration ratio in Al alloys. - Abstract: We have calculated surface segregation energies of 41 impurities by means of density functional theory calculations. An interesting periodical variation tendency was found for surface segregation energies derived. For the majority of main group elements, segregation energies are negative which means solute elements enrichment at Al surface is energetically more favorable than uniformly dissolution. Half of transition elements possess positive segregation energies and the energies are sensitive to surface crystallographic orientations. A strong correlation is found between the segregation energies at the Al surface and the surface energ of solute elements.

  1. Analysis of anti-condensation mechanism on superhydrophobic anodic aluminum oxide surface

    International Nuclear Information System (INIS)

    Wu, Yanpeng; Zhang, Chaoying

    2013-01-01

    Wetting theory about superhydrophobic surfaces reveals that hydrophobicity of surfaces has great relationship with surface roughness and surface free energy. Adopt electrochemical plus fluorine silane modified method to prepare superhydrophobic surface on anodic aluminum oxide surface, which not only enhances surface roughness, but also reduces surface free energy, even the static contact angle can reach 159.2° and anti-condensation is authenticated. Based on the experimental findings, analyze the reason of anti-condensation on superhydrophobic surfaces: one is that the density of droplets formed on superhydrophobic surfaces is low and the number of droplets is little; the other is bigger static contact angle and smaller rolling angle on superhydrophobic surfaces make droplets easy to detach on smaller tilt angle. This research can solve some condensation problems of equipment using in HVAC systems, such as heat exchangers in air conditioning system, cold radiation boards, air supply outlets, and so on. Highlights: • Prepare superhydrophobic surface on anodic aluminum oxide surface. • Analyze the reason of anti-condensation on superhydrophobic surfaces. • The density of droplets formed on superhydrophobic surfaces is low. • Droplets on superhydrophobic surfaces are easy to detach. • This research can solve some problems of equipment using in HVAC systems

  2. Method For Creating Corrosion Resistant Surface On An Aluminum Copper Alloy

    Science.gov (United States)

    Mansfeld, Florian B.; Wang, You; Lin, Simon H.

    1997-06-03

    A method for treating the surface of aluminum alloys hang a relatively high copper content is provided which includes the steps of removing substantially all of the copper from the surface, contacting the surface with a first solution containing cerium, electrically charging the surface while contacting the surface in an aqueous molybdate solution, and contacting the surface with a second solution containing cerium. The copper is substantially removed from the surface in the first step either by (i) contacting the surface with an acidic chromate solution or by (ii) contacting the surface with an acidic nitrate solution while subjecting the surface to an electric potential. The corrosion-resistant surface resulting from the invention is excellent, consistent and uniform throughout the surface. Surfaces treated by the invention may often be certified for use in salt-water services.

  3. 40 CFR 63.5755 - How do I demonstrate compliance with the aluminum recreational boat surface coating spray gun...

    Science.gov (United States)

    2010-07-01

    ... the aluminum recreational boat surface coating spray gun cleaning work practice standards? 63.5755... surface coating spray gun cleaning work practice standards? You must demonstrate compliance with the aluminum coating spray gun cleaning work practice standards by meeting the requirements of paragraph (a) or...

  4. Phosphate adsorption on aluminum-impregnated mesoporous silicates : surface structure and behavior of adsorbents

    Science.gov (United States)

    Eun Woo Shin; James S. Han; Min Jang; Soo-Hong Min; Jae Kwang Park; Roger M. Rowell

    2004-01-01

    Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface...

  5. Recent progress in the development and understanding of silicon surface passivation by aluminum oxide for photovoltaics

    NARCIS (Netherlands)

    Dingemans, G.; Kessels, W.M.M.

    2010-01-01

    In the recent years, considerable progress has been made in the understanding of the unique silicon surface passivation properties of aluminum oxide (Al2O3) films including its underlying mechanisms. Containing a high fixed negative charge density located close to the Si interface, Al2O3 provides a

  6. The effect of different aluminum alloy surface compositions on barrier anodic film formation

    International Nuclear Information System (INIS)

    Panitz, J.K.G.; Sharp, D.J.

    1984-01-01

    The authors have grown barrier anodic coatings on samples of aluminum alloy with different elemental surface compositions. In one series of experiments, they characterized the surface composition present on 6061 aluminum alloy samples after different chemical treatments including a detergent-water and methyl-ethyl ketone solvent clean, a 50% nitric acid-water etch, and a concentrated nitric acid-ammonium bifluoride etch. They anodized samples which were prepared similarly to those analyzed to evaluate the practical effects of the three different surface compositions. The anodization voltage rise time to 950V at constant current was used as a figure of merit. The solvent cleaned and the 50% nitric acid etched samples required, respectively, 113% and 41% more time to reach 950V than the concentrated nitric acidammonium bifloride etched samples. In a second series of experiments, they alternately anodized groups of either 6061 or 1100 (commercially pure) aluminum alloy, observed rise times to 950V, and measured chloride ion concentrations in the electrolyte. Longer rise times and higher chloride ion concentrations were observed for the 1100 samples. It was observed that the chloride ion concentration fell from initially high levels when 6061 samples were anodized. The results of both series of experiments augment the results of other investigators, who report that the surface species initially present on aluminum have a significant effect on anodic film formation

  7. Nicotine-magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Rades, Thomas; Puttipipatkhachorn, Satit

    2013-01-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle...

  8. Effect of electrical discharge machining on surface characteristics and machining damage of AISI D2 tool steel

    International Nuclear Information System (INIS)

    Guu, Y.H.; Hocheng, H.; Chou, C.Y.; Deng, C.S.

    2003-01-01

    In this work the electrical discharge machining (EDM) of AISI D2 tool steel was investigated. The surface characteristics and machining damage caused by EDM were studied in terms of machining parameters. Based on the experimental data, an empirical model of the tool steel was also proposed. A new damage variable was used to study the EDM damage. The workpiece surface and re-solidified layers were examined by a scanning electron microscopy. Surface roughness was determined with a surface profilometer. The residual stress acting on the EDM specimen was measured by the X-ray diffraction technique. Experimental results indicate that the thickness of the recast layer, and surface roughness are proportional to the power input. The EDM process introduces tensile residual stress on the machined surface. The EDM damage leads to strength degradation

  9. Robust biomimetic-structural superhydrophobic surface on aluminum alloy.

    Science.gov (United States)

    Li, Lingjie; Huang, Tao; Lei, Jinglei; He, Jianxin; Qu, Linfeng; Huang, Peiling; Zhou, Wei; Li, Nianbing; Pan, Fusheng

    2015-01-28

    The following facile approach has been developed to prepare a biomimetic-structural superhydrophobic surface with high stabilities and strong resistances on 2024 Al alloy that are robust to harsh environments. First, a simple hydrothermal treatment in a La(NO3)3 aqueous solution was used to fabricate ginkgo-leaf like nanostructures, resulting in a superhydrophilic surface on 2024 Al. Then a low-surface-energy compound, dodecafluoroheptyl-propyl-trimethoxylsilane (Actyflon-G502), was used to modify the superhydrophilic 2024 Al, changing the surface character from superhydrophilicity to superhydrophobicity. The water contact angle (WCA) of such a superhydrophobic surface reaches up to 160°, demonstrating excellent superhydrophobicity. Moreover, the as-prepared superhydrophobic surface shows high stabilities in air-storage, chemical and thermal environments, and has strong resistances to UV irradiation, corrosion, and abrasion. The WCAs of such a surface almost remain unchanged (160°) after storage in air for 80 days, exposure in 250 °C atmosphere for 24 h, and being exposed under UV irradiation for 24 h, are more than 144° whether in acidic or alkali medium, and are more than 150° after 48 h corrosion and after abrasion under 0.98 kPa for 1000 mm length. The remarkable durability of the as-prepared superhydrophobic surface can be attributed to its stable structure and composition, which are due to the existence of lanthanum (hydr)oxides in surface layer. The robustness of the as-prepared superhydrophobic surface to harsh environments will open their much wider applications. The fabricating approach for such robust superhydrophobic surface can be easily extended to other metals and alloys.

  10. The Influence of Surface Anisotropy Crystalline Structure on Wetting of Sapphire by Molten Aluminum

    Science.gov (United States)

    Aguilar-Santillan, Joaquin

    2013-05-01

    The wetting of sapphire by molten aluminum was investigated by the sessile drop technique from 1073 K to 1473 K (800 °C to 1200 °C) at PO2 <10-15 Pa under Ar atmosphere. This study focuses on sapphire crystalline structure and its principle to the interface. The planes " a" and " b" are oxygen terminated structures and wet more by Al, whereas the " c" plane is an aluminum terminated structure. A wetting transition at 1273 K (1000 °C) was obtained and a solid surface tension proves the capillarity trends of the couple.

  11. Scanning probe studies of water nucleation on aluminum oxide and gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Missert, N. [Sandia National Laboratories, Albuquerque, NM 87185-1415 (United States)], E-mail: namisse@sandia.gov; Copeland, R.G. [Sandia National Laboratories, Albuquerque, NM 87185-1415 (United States)

    2008-01-30

    The nucleation of nanoscale water at surfaces in humid environments is sensitive to several factors, including the details of the surface morphology, ability of the surface to hydrate and the presence of contaminants. Tapping mode atomic force microscopy was used to investigate the nucleation process as a function of relative humidity (RH) on passive aluminum and gold thin films. Films exposed to the ambient environment prior to RH exposure showed discrete structures with lateral sizes ranging from 10 to 100 nm only at RH > 70%. These structures formed preferentially at grain boundaries, triple points and regions with significant topography such as protruding grains. The morphology of the passive aluminum surface is permanently altered at the sites where discrete structures were observed; nodules with heights ranging from 0.5 to 2 nm persist even after reducing the RH to <2%. The gold surface does not show such a permanent change in morphology after reducing the RH. Passive aluminum films exposed to high RH immediately after growth (e.g. no ambient exposure) do not show discrete structures even at the highest RH exposures of 90%, suggesting a hydrophilic surface and the importance of surface hydrocarbon contaminants in affecting the distribution of the water layer.

  12. Scanning probe studies of water nucleation on aluminum oxide and gold surfaces

    International Nuclear Information System (INIS)

    Missert, N.; Copeland, R.G.

    2008-01-01

    The nucleation of nanoscale water at surfaces in humid environments is sensitive to several factors, including the details of the surface morphology, ability of the surface to hydrate and the presence of contaminants. Tapping mode atomic force microscopy was used to investigate the nucleation process as a function of relative humidity (RH) on passive aluminum and gold thin films. Films exposed to the ambient environment prior to RH exposure showed discrete structures with lateral sizes ranging from 10 to 100 nm only at RH > 70%. These structures formed preferentially at grain boundaries, triple points and regions with significant topography such as protruding grains. The morphology of the passive aluminum surface is permanently altered at the sites where discrete structures were observed; nodules with heights ranging from 0.5 to 2 nm persist even after reducing the RH to <2%. The gold surface does not show such a permanent change in morphology after reducing the RH. Passive aluminum films exposed to high RH immediately after growth (e.g. no ambient exposure) do not show discrete structures even at the highest RH exposures of 90%, suggesting a hydrophilic surface and the importance of surface hydrocarbon contaminants in affecting the distribution of the water layer

  13. Multitechnique characterization of CPTi surfaces after electro discharge machining (EDM).

    Science.gov (United States)

    Zinelis, Spiros; Al Jabbari, Youssef S; Thomas, Andrew; Silikas, Nick; Eliades, George

    2014-01-01

    The aim of this study was to comparatively assess the surface roughness parameters, the hardness, and the elemental and molecular alterations induced on CPTi surfaces after conventional finishing and finishing with electro discharge machining (EDM). A completed cast model of an arch that received four implants was used for the preparation of two grade II CPTi castings. One framework was conventionally finished (CF), whereas the other was subjected to EDM finishing. The surface morphology was imaged employing SEM. 3D surface parameters (S a, S q, S z, S ds, S dr, and S ci) were calculated by optical profilometry. The elemental composition of the treated surfaces was determined by energy dispersive X-ray analysis, whereas the elemental and chemical states of the outmost layer were investigated by X-ray photoelectron spectrometry. Surface hardness was also tested with a Knoop indenter. The results of surface roughness parameters, elemental analysis, and hardness were compared using unpaired t test (a = 0.05). The EDM group demonstrated a rougher surface, with a significant uptake of C and Cu. The CF surface mainly consisted of TiO2. On EDM surface though, Ti was probed in different chemicals states (TiO2, Ti2O3, TiC and metallic Ti) and Cu was traced as Cu2O and CuO. Hardness after EDM was almost ten times higher than CF. EDM significantly affected surface roughness, chemical state, and hardness properties of grade II CPTi castings in comparison with CF. The morphological and elemental alterations of EDM-treated CPTi surfaces may strongly contribute to the reduced corrosion resistance documented for this procedure. The degradation of electrochemical properties may have further biological implications through ionic release in the oral environment.

  14. Boric Acid as an Accelerator of Cerium Surface Treatment on Aluminum

    Directory of Open Access Journals (Sweden)

    K. Cruz-Hernández

    2014-01-01

    Full Text Available Aluminum pieces are often used in various industrial processes like automotive and aerospace manufacturing, as well as in ornamental applications, so it is necessary to develop processes to protect these materials, processes that can be industrialized to protect the aluminum as well or better than chromate treatments. The purpose of this research is to evaluate boric acid as an accelerator by optimizing its concentration in cerium conversion coatings (CeCC with 10-minute immersion time with a concentration of 0.1 g L−1 over aluminum to protect it. The evaluation will be carried out by measuring anticorrosion properties with electrochemical techniques (polarization resistance, Rp, polarization curves, PC, and electrochemical impedance spectroscopy, EIS in NaCl 3.5% wt. aqueous solution and surface characterization with scanning electron microscopy (SEM.

  15. First principle study of structural, electronic and fermi surface properties of aluminum praseodymium

    Science.gov (United States)

    Shugani, Mani; Aynyas, Mahendra; Sanyal, S. P.

    2018-05-01

    We present a structural, Electronic and Fermi surface properties of Aluminum Praseodymium (AlPr) using First-principles density functional calculation by using full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA). The ground state properties along with electronic and Fermi surface properties are studied. It is found that AlPr is metallic and the bonding between Al and Pr is covalent.

  16. A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

    OpenAIRE

    Chen, Po Chun; Hsieh, Sheng Jen; Chen, Chien Chon; Zou, Jun

    2013-01-01

    We proposed fabricating an aluminum microneedle array with a nanochannel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The microneedle array provides a three-dimensional (3D) structure that possesses several hundred times more surface area than a traditional nanochannel template. Therefore, the microneedle array can potentially be used in many technology applications. This 3D microneedle array device can not only be used for painless inj...

  17. Fabrication of Superhydrophobic Metallic Surface by Wire Electrical Discharge Machining for Seamless Roll-to-Roll Printing

    Directory of Open Access Journals (Sweden)

    Jin-Young So

    2018-04-01

    Full Text Available This paper presents a proposal of a direct one-step method to fabricate a multi-scale superhydrophobic metallic seamless roll mold. The mold was fabricated using the wire electrical discharge machining (WEDM technique for a roll-to-roll imprinting application to produce a large superhydrophobic surface. Taking advantage of the exfoliating characteristic of the metallic surface, nano-sized surface roughness was spontaneously formed while manufacturing the micro-sized structure: that is, a dual-scale hierarchical structure was easily produced in a simple one-step fabrication with a large area on the aluminum metal surface. This hierarchical structure showed superhydrophobicity without chemical coating. A roll-type seamless mold for the roll-to-roll process was fabricated through engraving the patterns on the cylindrical substrate, thereby enabling to make a continuous film with superhydrophobicity.

  18. Effects of Hypervelocity Impacts on Silicone Elastomer Seals and Mating Aluminum Surfaces

    Science.gov (United States)

    deGroh, Henry C., III; Steinetz, Bruce M.

    2009-01-01

    While in space silicone based elastomer seals planned for use on NASA's Crew Exploration Vehicle (CEV) are exposed to threats from micrometeoroids and orbital debris (MMOD). An understanding of these threats is required to assess risks to the crew, the CEV orbiter, and missions. An Earth based campaign of hypervelocity impacts on small scale seal rings has been done to help estimate MMOD threats to the primary docking seal being developed for the Low Impact Docking System (LIDS). LIDS is being developed to enable the CEV to dock to the ISS (International Space Station) or to Altair (NASA's next lunar lander). The silicone seal on LIDS seals against aluminum alloy flanges on ISS or Altair. Since the integrity of a seal depends on both sealing surfaces, aluminum targets were also impacted. The variables considered in this study included projectile mass, density, speed, incidence angle, seal materials, and target surface treatments and coatings. Most of the impacts used a velocity near 8 km/s and spherical aluminum projectiles (density = 2.7 g/cubic cm), however, a few tests were done near 5.6 km/s. Tests were also performed using projectile densities of 7.7, 2.79, 2.5 or 1.14 g/cubic cm. Projectile incidence angles examined included 0 deg, 45 deg, and 60 deg from normal to the plane of the target. Elastomer compounds impacted include Parker's S0383-70 and Esterline's ELA-SA-401 in the as received condition, or after an atomic oxygen treatment. Bare, anodized and nickel coated aluminum targets were tested simulating the candidate mating seal surface materials. After impact, seals and aluminum plates were leak tested: damaged seals were tested against an undamaged aluminum plate; and undamaged seals were placed at various locations over craters in aluminum plates. It has been shown that silicone elastomer seals can withstand an impressive level of damage before leaking beyond allowable limits. In general on the tests performed to date, the diameter of the crater in

  19. Materials study for reacting plasma machine

    International Nuclear Information System (INIS)

    Kamada, Kohji; Hamada, Yasuji

    1982-01-01

    A new reacting plasma machine is designed, and will be constructed at the Institute of Plasma Physics, Nagoya University. It is important to avoid the activation of the materials for the machine, accordingly, aluminum alloy has been considered as the material since the induced activity of aluminum due to 14 MeV neutrons is small. The vacuum chamber of the new machine consists of four modules, and the remote control of each module is considered. However, the cost of the remote control of modules is expensive. To minimize the dependence on the remote control, the use of aluminum alloy is considered as the first step. The low electrical resistivity, over-ageing, weak mechanical strength and eddy current characteristics of aluminum alloy must be improved. The physical and electrical properties of various aluminum alloys have been investigated. Permeability of hydrogen through aluminum, the recycling characteristics and surface coating materials have been also studied. (Kato, T.)

  20. Surface Quality Improvement of AA6060 Aluminum Extruded Components through Liquid Nitrogen Mold Cooling

    Directory of Open Access Journals (Sweden)

    Andrea Francesco Ciuffini

    2018-06-01

    Full Text Available 6xxx aluminum alloys are suitable for the realization of both structural applications and architectural decorative elements, thanks to the combination of high corrosion resistance and good surface finish. In areas where the aesthetic aspects are fundamental, further improvements in surface quality are significant. The cooling of the extrusion mold via internal liquid nitrogen fluxes is emerging as an important innovation in aluminum extrusion. Nowadays, this innovation is providing a large-scale solution to obtain high quality surface finishes in extruded aluminum semi-finished products. These results are also coupled to a significant increase in productivity. The aim of the work is to compare the surface quality of both cooled liquid nitrogen molds and classically extruded products. In this work, adhesion phenomena, occurring during the extrusion between the mold and the flowing material, have been detected as the main causes of the presence of surface defects. The analysis also highlighted a strong increase in the surface quality whenever the extrusion mold was cooled with liquid nitrogen fluxes. This improvement has further been confirmed by an analysis performed on the finished products, after painting and chromium plating. This work on the AA6060 alloy has moreover proceeded to roughness measurements and metallographic analyses, to investigate the eventual occurrence of other possible benefits stemming from this new extrusion mold cooling technology.

  1. Hierarchically ordered self-lubricating superhydrophobic anodized aluminum surfaces with enhanced corrosion resistance.

    Science.gov (United States)

    Vengatesh, Panneerselvam; Kulandainathan, Manickam Anbu

    2015-01-28

    Herein, we report a facile method for the fabrication of self-lubricating superhydrophobic hierarchical anodic aluminum oxide (AAO) surfaces with improved corrosion protection, which is greatly anticipated to have a high impact in catalysis, aerospace, and the shipping industries. This method involves chemical grafting of as-formed AAO using low surface free energy molecules like long chain saturated fatty acids, perfluorinated fatty acid (perfluorooctadecanoic acid, PFODA), and perfluorosulfonicacid-polytetrafluoroethylene copolymer. The pre and post treatment processes in the anodization of aluminum (Al) play a vital role in the grafting of fatty acids. Wettability and surface free energy were analyzed using a contact angle meter and achieved 161.5° for PFODA grafted anodized aluminum (PFODA-Al). This study was also aimed at evaluating the surface for corrosion resistance by Tafel polarization and self-lubricating properties by tribological studies using a pin-on-disc tribometer. The collective results showed that chemically grafted AAO nanostructures exhibit high corrosion resistance toward seawater and low frictional coefficient due to low surface energy and self-lubricating property of fatty acids covalently linked to anodized Al surfaces.

  2. Micro-mechanisms of Surface Defects Induced on Aluminum Alloys during Plastic Deformation at Elevated Temperatures

    Science.gov (United States)

    Gali, Olufisayo A.

    Near-surface deformed layers developed on aluminum alloys significantly influence the corrosion and tribological behavior as well as reduce the surface quality of the rolled aluminum. The evolution of the near-surface microstructures induced on magnesium containing aluminum alloys during thermomechanical processing has been investigated with the aim generating an understanding of the influence of individual forming parameters on its evolution and examine the microstructure of the roll coating induced on the mating steel roll through material transfer during rolling. The micro-mechanisms related to the various features of near-surface microstructure developed during tribological conditions of the simulated hot rolling process were identified. Thermomechanical processing experiments were performed with the aid of hot rolling (operating temperature: 550 to 460 °C, 4, 10 and 20 rolling pass schedules) and hot forming (operating temperature: 350 to 545 °C, strain rate: 4 x 10-2 s-1) tribo-simulators. The surface, near-surface features and material transfer induced during the elevated temperature plastic deformation were examined and characterized employing optical interferometry, SEM/EDS, FIB and TEM. Near-surface features characterized on the rolled aluminum alloys included; cracks, fractured intermetallic particles, aluminum nano-particles, oxide decorated grain boundaries, rolled-in oxides, shingles and blisters. These features were related to various individual rolling parameters which included, the work roll roughness, which induced the formation of shingles, rolling marks and were responsible for the redistribution of surface oxide and the enhancements of the depth of the near-surface damage. The enhanced stresses and strains experienced during rolling were related to the formation and propagation of cracks, the nanocrystalline structure of the near-surface layers and aluminum nano-particles. The mechanism of the evolution of the near-surface microstructure were

  3. Surface analysis of anodized aluminum clamps from NASA-LDEF satellite

    Science.gov (United States)

    Grammer, H. L.; Wightman, J. P.; Young, Philip R.

    1992-01-01

    Surface analysis results of selected anodized aluminum clamps containing black (Z306) and white (A276) paints which received nearly six years of Low Earth Orbit (LEO) exposure on the Long Duration Exposure Facility are reported. Surface analytical techniques, including x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy/energy dispersive analysis by x-ray (SEM/EDAX), showed significant differences in the surface composition of these materials depending upon the position on the LDEF. Differences in the surface composition are attributed to varying amounts of atomic oxygen and vacuum ultraviolet radiation (VUV). Silicon containing compounds were the primary contaminant detected on the materials.

  4. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  5. Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes.

    Science.gov (United States)

    Xiong, Guang; Elam, Jeffrey W; Feng, Hao; Han, Catherine Y; Wang, Hsien-Hau; Iton, Lennox E; Curtiss, Larry A; Pellin, Michael J; Kung, Mayfair; Kung, Harold; Stair, Peter C

    2005-07-28

    Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.

  6. Surface and subsurface cracks characteristics of single crystal SiC wafer in surface machining

    Energy Technology Data Exchange (ETDEWEB)

    Qiusheng, Y., E-mail: qsyan@gdut.edu.cn; Senkai, C., E-mail: senkite@sina.com; Jisheng, P., E-mail: panjisheng@gdut.edu.cn [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou, 510006 (China)

    2015-03-30

    Different machining processes were used in the single crystal SiC wafer machining. SEM was used to observe the surface morphology and a cross-sectional cleavages microscopy method was used for subsurface cracks detection. Surface and subsurface cracks characteristics of single crystal SiC wafer in abrasive machining were analysed. The results show that the surface and subsurface cracks system of single crystal SiC wafer in abrasive machining including radial crack, lateral crack and the median crack. In lapping process, material removal is dominated by brittle removal. Lots of chipping pits were found on the lapping surface. With the particle size becomes smaller, the surface roughness and subsurface crack depth decreases. When the particle size was changed to 1.5µm, the surface roughness Ra was reduced to 24.0nm and the maximum subsurface crack was 1.2µm. The efficiency of grinding is higher than lapping. Plastic removal can be achieved by changing the process parameters. Material removal was mostly in brittle fracture when grinding with 325# diamond wheel. Plow scratches and chipping pits were found on the ground surface. The surface roughness Ra was 17.7nm and maximum subsurface crack depth was 5.8 µm. When grinding with 8000# diamond wheel, the material removal was in plastic flow. Plastic scratches were found on the surface. A smooth surface of roughness Ra 2.5nm without any subsurface cracks was obtained. Atomic scale removal was possible in cluster magnetorheological finishing with diamond abrasive size of 0.5 µm. A super smooth surface eventually obtained with a roughness of Ra 0.4nm without any subsurface crack.

  7. Discrete microfluidics based on aluminum nitride surface acoustic wave devices

    OpenAIRE

    Zhou, J.; Pang, H.F.; Garcia-Gancedo, L.; Iborra, E.; Clement, M.; De Miguel-Ramos, M.; Jin, H.; Luo, J.K.; Smith, S.; Dong, S.R.; Wang, D.M.; Fu, Y.Q.

    2015-01-01

    To date, most surface acoustic wave (SAW) devices have been made from bulk piezoelectric materials, such as quartz, lithium niobate or lithium tantalite. These bulk materials are brittle, less easily integrated with electronics for control and signal processing, and difficult to realize multiple wave modes or apply complex electrode designs. Using thin film SAWs makes it convenient to integrate microelectronics and multiple sensing or microfluidics techniques into a lab-on-a-chip with low cos...

  8. Some corrosion effects of the aluminum tank surface of Dalat research reactor

    International Nuclear Information System (INIS)

    Nguyen Mong Sinh

    1995-01-01

    The Dalat Nuclear Research Reactor was reconstructed from the TRIGA-MARK-II reactor installed in 1963 with a nominal power of 250 kW. Reconstruction and upgrading of this reactor to nominal power of 500 kW had been completed in the end of 1983. The reactor was commissioned in the beginning of March 1984. The aluminum reactor tank and some components of the former reactor are more than 30 year old. The good quality of reactor water minimized the total corrosion rate of reactor material surface. But some local corrosion had been found out at the tank bottom especially in water stagnant areas. The corrosion processes could be due to the electrochemical reactions associated with different metals and alloys in the reactor water and keeping in touch with the surface of aluminum reactor tank. (orig.)

  9. The Evaluation of Surface Integrity During Machining of Inconel 718 with Various Laser Assistance Strategies

    Directory of Open Access Journals (Sweden)

    Wojciechowski Szymon

    2017-01-01

    Full Text Available The paper is focused on the evaluation of surface integrity formed during turning of Inconel 718 with the application of various laser assistance strategies. The primary objective of the work was to determine the relations between the applied machining strategy and the obtained surface integrity, in order to select the effective cutting conditions allowing the obtainment of high surface quality. The carried out experiment included the machining of Inconel 718 in the conventional turning conditions, as well as during the continuous laser assisted machining and sequential laser assistance. The surface integrity was evaluated by the measurements of machined surface topographies, microstructures and the microhardness. Results revealed that surface integrity of Inconel 718 is strongly affected by the selected machining strategy. The significant improvement of the surface roughness formed during machining of Inconel 718, can be reached by the application of simultaneous laser heating and cutting (LAM.

  10. Biomimetic superhydrophobic surface of high adhesion fabricated with micronano binary structure on aluminum alloy.

    Science.gov (United States)

    Liu, Yan; Liu, Jindan; Li, Shuyi; Liu, Jiaan; Han, Zhiwu; Ren, Luquan

    2013-09-25

    Triggered by the microstructure characteristics of the surfaces of typical plant leaves such as the petals of red roses, a biomimetic superhydrophobic surface with high adhesion is successfully fabricated on aluminum alloy. The essential procedure is that samples were processed by a laser, then immersed and etched in nitric acid and copper nitrate, and finally modified by DTS (CH3(CH2)11Si(OCH3)3). The obtained surfaces exhibit a binary structure consisting of microscale crater-like pits and nanoscale reticula. The superhydrophobicity can be simultaneously affected by the micronano binary structure and chemical composition of the surface. The contact angle of the superhydrophobic surface reaches up to 158.8 ± 2°. Especially, the surface with micronano binary structure is revealed to be an excellent adhesive property with petal-effect. Moreover, the superhydrophobic surfaces show excellent stability in aqueous solution with a large pH range and after being exposed long-term in air. In this way, the multifunctional biomimetic structural surface of the aluminum alloy is fabricated. Furthermore, the preparation technology in this article provides a new route for other metal materials.

  11. Controllable superhydrophobic aluminum surfaces with tunable adhesion fabricated by femtosecond laser

    Science.gov (United States)

    Song, Yuxin; Wang, Cong; Dong, Xinran; Yin, Kai; Zhang, Fan; Xie, Zheng; Chu, Dongkai; Duan, Ji'an

    2018-06-01

    In this study, a facile and detailed strategy to fabricate superhydrophobic aluminum surfaces with controllable adhesion by femtosecond laser ablation is presented. The influences of key femtosecond laser processing parameters including the scanning speed, laser power and interval on the wetting properties of the laser-ablated surfaces are investigated. It is demonstrated that the adhesion between water and superhydrophobic surface can be effectively tuned from extremely low adhesion to high adhesion by adjusting laser processing parameters. At the same time, the mechanism is discussed for the changes of the wetting behaviors of the laser-ablated surfaces. These superhydrophobic surfaces with tunable adhesion have many potential applications, such as self-cleaning surface, oil-water separation, anti-icing surface and liquid transportation.

  12. The influence of surface topography on the forming friction of automotive aluminum sheet

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Pamela Ann [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1998-05-01

    Interest in utilizing aluminum alloys in automobiles has increased in recent years as a result of the desire to lower automobile weight and, consequently, increase fuel economy. While aluminum alloy use in cast parts has increased, outer body panel applications are still being investigated. The industry is interested in improving the formability of these sheet alloys by a combination of alloy design and processing. A different avenue of improving the formability of these alloys may be through patterning of the sheet surface. Surface patterns hold the lubricant during the forming process, with a resulting decrease in the sheet-die surface contact. While it has been speculated that an optimum surface pattern would consist of discrete cavities, detailed investigation into the reduction of forming friction by utilizing discrete patterns is lacking. A series of discrete patterns were investigated to determine the dependence of the forming friction of automotive aluminum alloys on pattern lubricant carrying capacity and on material strength. Automotive aluminum alloys used in outer body panel applications were rolled on experimental rolls that had been prepared with a variety of discrete patterns. All patterns for each alloy were characterized before and after testing both optically and, to determine pattern lubricant capacity, using three dimensional laser profilometry. A draw bead simulation (DBS) friction tester was designed and fabricated to determine the forming friction of the patterned sheets. Tensile testing and frictionless DBS testing were performed to ascertain the material properties of each sheet. The most striking result of this work was the inversely linear dependence of forming friction on the lubricant carrying capacity of the discrete patterns.

  13. Surface conductivity of the single crystal aluminum oxide in vacuum and caesium vapors

    International Nuclear Information System (INIS)

    Vasilchenko, A.V.; Izhvanov, O.L.

    1996-01-01

    Results of measurements of surface conductivity of single-crystal aluminum oxide samples in vacuum and cesium vapors at T=620 endash 830 K and P Cs =0.13 endash 2 Pa are shown in the paper. Analysis of caesium vapor influence is carried out and ultimate characteristics of samples conductivity under operation conditions in thermionic nuclear power system (NPP) TFE are estimated. copyright 1996 American Institute of Physics

  14. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu Tao, E-mail: liutao@shmtu.edu.c [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China); Dong Lihua; Liu Tong; Yin Yansheng [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China)

    2010-07-15

    Electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy were carried out to determine the effect of super-hydrophobic surfaces on the marine bacterium Vibrio natriegens (V. natriegens) adhesion. Four different samples were prepared in order to investigate the anti-biocorrosion mechanism of super-hydrophobic surfaces. Potentiodynamic polarization suggested that the V. natriegens attached on the surface mainly enhanced the reaction kinetics of the anodic reaction and accelerated the dissolution of aluminum. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that neither anodization nor chemical modification could decrease the bacterial adhesion and corrosion rate individually. V. natriegens showed only weak attachment to the super-hydrophobic surface, and the biocorrosion mechanism was closely associated with surface energy and surface topography.

  15. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces

    International Nuclear Information System (INIS)

    Liu Tao; Dong Lihua; Liu Tong; Yin Yansheng

    2010-01-01

    Electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy were carried out to determine the effect of super-hydrophobic surfaces on the marine bacterium Vibrio natriegens (V. natriegens) adhesion. Four different samples were prepared in order to investigate the anti-biocorrosion mechanism of super-hydrophobic surfaces. Potentiodynamic polarization suggested that the V. natriegens attached on the surface mainly enhanced the reaction kinetics of the anodic reaction and accelerated the dissolution of aluminum. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that neither anodization nor chemical modification could decrease the bacterial adhesion and corrosion rate individually. V. natriegens showed only weak attachment to the super-hydrophobic surface, and the biocorrosion mechanism was closely associated with surface energy and surface topography.

  16. Effect of operational conditions of electroerosion machining on the surface microgeometry parameters of steels and alloys

    International Nuclear Information System (INIS)

    Foteev, N.K.

    1976-01-01

    Studies the influence of pulse duration and a series of operating conditions of a ShGI-40-440 spark-machining generator on changes in the basic surface microgeometry characteristics of components of stainless steel 1Kh18N10T, steel St 45 and hard alloy T14K8. The microgeometry characteristics of spark-machined surfaces differ significantly from the corresponding characteristics of surfaces machined by cutting and vibro-rolling

  17. Aluminum surface corrosion and the mechanism of inhibitors using pH and metal ion selective imaging fiber bundles.

    Science.gov (United States)

    Szunerits, Sabine; Walt, David R

    2002-02-15

    The localized corrosion behavior of a galvanic aluminum copper couple was investigated by in situ fluorescence imaging with a fiber-optic imaging sensor. Three different, but complementary methods were used for visualizing remote corrosion sites, mapping the topography of the metal surface, and measuring local chemical concentrations of H+, OH-, and Al3+. The first method is based on a pH-sensitive imaging fiber, where the fluorescent dye SNAFL was covalently attached to the fiber's distal end. Fluorescence images were acquired as a function of time at different areas of the galvanic couple. In a second method, the fluorescent dye morin was immobilized on the fiber-optic imaging sensor, which allowed the in situ localization of corrosion processes on pure aluminum to be visualized over time by monitoring the release of Al3+. The development of fluorescence on the aluminum surface defined the areas associated with the anodic dissolution of aluminum. We also investigated the inhibition of corrosion of pure aluminum by CeCl3 and 8-hydroxyquinoline. The decrease in current, the decrease in the number of active sites on the aluminum surface, and the faster surface passivation are all consistent indications that cerium chloride and 8-hydroxyquinoline inhibit corrosion effectively. From the number and extent of corrosion sites and the release of aluminum ions monitored with the fiber, it was shown that 8-hydroxyquinoline is a more effective inhibitor than cerium chloride.

  18. Solid surface vs. liquid surface: nanoarchitectonics, molecular machines, and DNA origami.

    Science.gov (United States)

    Ariga, Katsuhiko; Mori, Taizo; Nakanishi, Waka; Hill, Jonathan P

    2017-09-13

    The investigation of molecules and materials at interfaces is critical for the accumulation of new scientific insights and technological advances in the chemical and physical sciences. Immobilization on solid surfaces permits the investigation of different properties of functional molecules or materials with high sensitivity and high spatial resolution. Liquid surfaces also present important media for physicochemical innovation and insight based on their great flexibility and dynamicity, rapid diffusion of molecular components for mixing and rearrangements, as well as drastic spatial variation in the prevailing dielectric environment. Therefore, a comparative discussion of the relative merits of the properties of materials when positioned at solid or liquid surfaces would be informative regarding present-to-future developments of surface-based technologies. In this perspective article, recent research examples of nanoarchitectonics, molecular machines, DNA nanotechnology, and DNA origami are compared with respect to the type of surface used, i.e. solid surfaces vs. liquid surfaces, for future perspectives of interfacial physics and chemistry.

  19. Compressive strength, plastic flow properties, and surface frictional effects of 1100, 3003 and 6061 aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pinkerton, Gary Wayne [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1993-01-01

    The purpose of this study is to find aluminum alloys that are effective for use as wire vacuum seals in the 800MeV particle accelerator located at the Louis Anderson Meson Physics Facility (LAMPF) in Los Alamos, NM. Three alloys, Al 1100, Al 3003, and Al 6061, are investigated under uniaxial compression to determine stresses for a given height reduction from 0 to 70 percent, and to find plastic flow and surface interaction effects. Right-circular cylindrical specimens are compressed on-end (cylindrically) and radially (for modeling as compressed wire). Aluminum 1100 and 3003 alloys are compared for length to diameter ratios of 1 and 2 for both compression types, and are then compared to results of radial compression of annealed small diameter Al 1100 wire currently used at LAMPE. The specimens are also compressed between three different platen surfaces, polished steel, etched steel, and aluminum 6061-T6, to determine effects of friction. The Al 3003 alloy exhibits 20 to 25% lower stresses at all height reductions than Al 1100 for both cylindrical and radial compression.

  20. Compressive strength, plastic flow properties, and surface frictional effects of 1100, 3003 and 6061 aluminum alloys

    International Nuclear Information System (INIS)

    Pinkerton, G.W.

    1993-01-01

    The purpose of this study is to find aluminum alloys that are effective for use as wire vacuum seals in the 800MeV particle accelerator located at the Louis Anderson Meson Physics Facility (LAMPF) in Los Alamos, NM. Three alloys, Al 1100, Al 3003, and Al 6061, are investigated under uniaxial compression to determine stresses for a given height reduction from 0 to 70 percent, and to find plastic flow and surface interaction effects. Right-circular cylindrical specimens are compressed on-end (cylindrically) and radially (for modeling as compressed wire). Aluminum 1100 and 3003 alloys are compared for length to diameter ratios of 1 and 2 for both compression types, and are then compared to results of radial compression of annealed small diameter Al 1100 wire currently used at LAMPE. The specimens are also compressed between three different platen surfaces, polished steel, etched steel, and aluminum 6061-T6, to determine effects of friction. The Al 3003 alloy exhibits 20 to 25% lower stresses at all height reductions than Al 1100 for both cylindrical and radial compression

  1. High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

    Science.gov (United States)

    Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

    2016-12-01

    We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2-22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the system about 700-900 K are optimal parameters for production of high-quality layers of copper on the aluminum surface. These conditions provide both a good adhesion and a less degree of the plastic deformation. At the same time, higher impact velocities can be used for combined treatment consisting of both the plastic deformation and the coating.

  2. Deformation characteristics of the near-surface layers of zirconia ceramics implanted with aluminum ions

    Science.gov (United States)

    Ghyngazov, S. A.; Vasiliev, I. P.; Frangulyan, T. S.; Chernyavski, A. V.

    2015-10-01

    The effect of ion treatment on the phase composition and mechanical properties of the near-surface layers of zirconium ceramic composition 97 ZrO2-3Y2O3 (mol%) was studied. Irradiation of the samples was carried out by accelerated ions of aluminum with using vacuum-arc source Mevva 5-Ru. Ion beam had the following parameters: the energy of the accelerated ions E = 78 keV, the pulse current density Ji = 4mA / cm2, current pulse duration equal τ = 250 mcs, pulse repetition frequency f = 5 Hz. Exposure doses (fluence) were 1016 и 1017 ion/cm2. The depth distribution implanted ions was studied by SIMS method. It is shown that the maximum projected range of the implanted ions is equal to 250 nm. Near-surface layers were investigated by X-ray diffraction (XRD) at fixed glancing incidence angle. It is shown that implantation of aluminum ions into the ceramics does not lead to a change in the phase composition of the near-surface layer. The influence of implanted ions on mechanical properties of ceramic near-surface layers was studied by the method of dynamic nanoindentation using small loads on the indenter P=300 mN. It is shown that in ion- implanted ceramic layer the processes of material recovery in the deformed region in the unloading mode proceeds with higher efficiency as compared with the initial material state. The deformation characteristics of samples before and after ion treatment have been determined from interpretation of the resulting P-h curves within the loading and unloading sections by the technique proposed by Oliver and Pharr. It was found that implantation of aluminum ions in the near-surface layer of zirconia ceramics increases nanohardness and reduces the Young's modulus.

  3. Surface quality analysis of die steels in powder-mixed electrical discharge machining using titan powder in fine machining

    Directory of Open Access Journals (Sweden)

    Banh Tien Long

    2016-06-01

    Full Text Available Improving the quality of surface molds after electrical discharge machining is still being considered by many researchers. Powder-mixed dielectric in electrical discharge machining showed that it is one of the processing methods with high efficiency. This article reports on the results of surface quality of mold steels after powder-mixed electrical discharge machining using titanium powder in fine machining. The process parameters such as electrode material, workpiece material, electrode polarity, pulse on-time, pulse off-time, current, and titanium powder concentration were considered in the research. These materials are most commonly used with die-sinking electrical discharge machining in the manufacture of molds and has been selected as the subject of research: workpiece materials were SKD61, SKT4, and SKD11 mold steels, and electrode materials were copper and graphite. Taguchi’s method is used to design experiments. The influence of the parameters on surface roughness was evaluated through the average value and ratio (S/N. Results showed that the parameters such as electrical current, electrode material, pulse on-time, electrode polarity, and interaction between the electrode materials with concentration powder mostly influence surface roughness and surface roughness at optimal parameters SRopt = 1.73 ± 0.39 µm. Analysis of the surface layer after powder-mixed electrical discharge machining using titanium powder in optimal conditions has shown that the white layer with more uniform thickness and increased hardness (≈861.0 HV, and amount and size of microscopic cracks, is reduced. This significantly leads to the increase in the quality of the surface layer.

  4. CORROSION AND SURFACE PROTECTION IN MACHINE MATERIALS FRICTION HAVE DIFFERENT SURFACE PAIRS EXPERIMENTAL INVESTIGATION OF FACTORS

    Directory of Open Access Journals (Sweden)

    Senai YALCINKAYA

    2017-05-01

    Full Text Available Friction force, normal force, linear change. The normal force varies with the loads on the friction object. In order to determine the friction force and the friction coefficient, the friction object and the friction speed are used. The experimental work was carried out in three stages. In the first stage, the effect of normal force on the friction force was studied. In the second step, the friction force of the friction surface area is influenced. The effect of the change of the shear rate in step 3 on the friction force was investigated. At the last stage, the experimental study of the effect of the material selection on the friction force was made and it was seen that the aluminum / brass surface pair had the smallest friction coefficient as a result of the opening. The greatest coefficient of friction is found in the pair of glass / felt objects.

  5. Retardation of surface corrosion of biodegradable magnesium-based materials by aluminum ion implantation

    Science.gov (United States)

    Wu, Guosong; Xu, Ruizhen; Feng, Kai; Wu, Shuilin; Wu, Zhengwei; Sun, Guangyong; Zheng, Gang; Li, Guangyao; Chu, Paul K.

    2012-07-01

    Aluminum ion implantation is employed to modify pure Mg as well as AZ31 and AZ91 magnesium alloys and their surface degradation behavior in simulated body fluids is studied. Polarization tests performed in conjunction with scanning electron microscopy (SEM) reveal that the surface corrosion resistance after Al ion implantation is improved appreciably. This enhancement can be attributed to the formation of a gradient surface structure with a gradual transition from an Al-rich oxide layer to Al-rich metal layer. Compared to the high Al-content magnesium alloy (AZ91), a larger reduction in the degradation rate is achieved from pure magnesium and AZ31. Our results reveal that the surface corrosion resistance of Mg alloys with no or low Al content can be improved by Al ion implantation.

  6. Retardation of surface corrosion of biodegradable magnesium-based materials by aluminum ion implantation

    International Nuclear Information System (INIS)

    Wu Guosong; Xu Ruizhen; Feng Kai; Wu Shuilin; Wu Zhengwei; Sun Guangyong; Zheng Gang; Li Guangyao; Chu, Paul K.

    2012-01-01

    Aluminum ion implantation is employed to modify pure Mg as well as AZ31 and AZ91 magnesium alloys and their surface degradation behavior in simulated body fluids is studied. Polarization tests performed in conjunction with scanning electron microscopy (SEM) reveal that the surface corrosion resistance after Al ion implantation is improved appreciably. This enhancement can be attributed to the formation of a gradient surface structure with a gradual transition from an Al-rich oxide layer to Al-rich metal layer. Compared to the high Al-content magnesium alloy (AZ91), a larger reduction in the degradation rate is achieved from pure magnesium and AZ31. Our results reveal that the surface corrosion resistance of Mg alloys with no or low Al content can be improved by Al ion implantation.

  7. Reduction of surface erosion caused by helium blistering in sintered beryllium and sintered aluminum powder

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminsky, M.

    1976-01-01

    Studies have been conducted to find materials with microstructures which minimize the formation of blisters. A promising class of materials appears to be sintered metal powder with small average grain sizes and low atomic number Z. Studies of the surface erosion of sintered aluminum powder (SAP 895) and of aluminum held at 400 0 C due to blistering by 100 keV helium ions have been conducted and the results are compared to those obtained earlier for room temperature irradiation. A significant reduction of the erosion rate in SAP 895 in comparison to annealed aluminum and SAP 930 is observed. In addition results on the blistering of sintered beryllium powder (type I) irradiated at room temperature and 600 0 C by 100 keV helium ions are given. These results will be compared with those reported recently for vacuum cast beryllium foil and a foil of sintered beryllium powder (type II) which was fabricated differently, than type I. For room temperature irradiation only a few blisters could be observed in sintered beryllium powder type I and type II and they are smaller in size and in number than in vacuum cast beryllium. For irradiation at 600 0 C large scale exfoliation of blisters was observed for vacuum cast beryllium but much less exfoliation was seen for sintered beryllium powder, type I, and type II. The results show a reduction in erosion rate cast beryllium, for both room temperature and 600 0 C

  8. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kanjanakawinkul, Watchara [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Rades, Thomas [School of Pharmacy, University of Otago, Dunedin 9054 (New Zealand); Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark); Puttipipatkhachorn, Satit [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand); Pongjanyakul, Thaned, E-mail: thaned@kku.ac.th [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2013-04-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties.

  9. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    International Nuclear Information System (INIS)

    Kanjanakawinkul, Watchara; Rades, Thomas; Puttipipatkhachorn, Satit; Pongjanyakul, Thaned

    2013-01-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties

  10. Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M Mohan; Gorin, Alexander [School of Engineering and Science, Curtin University of Technology, Sarawak (Malaysia); Abou-El-Hossein, K A, E-mail: mohan.m@curtin.edu.my [Mechanical and Aeronautical Department, Nelson Mandela Metropolitan University, Port Elegebeth, 6031 (South Africa)

    2011-02-15

    Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

  11. Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

    International Nuclear Information System (INIS)

    Reddy, M Mohan; Gorin, Alexander; Abou-El-Hossein, K A

    2011-01-01

    Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

  12. Fabrication of the micro/nano-structure superhydrophobic surface on aluminum alloy by sulfuric acid anodizing and polypropylene coating.

    Science.gov (United States)

    Wu, Ruomei; Liang, Shuquan; Liu, Jun; Pan, Anqiang; Yu, Y; Tang, Yan

    2013-03-01

    The preparation of the superhydrophobic surface on aluminum alloy by anodizing and polypropylene (PP) coating was reported. Both the different anodizing process and different PP coatings of aluminum alloy were investigated. The effects of different anodizing conditions, such as electrolyte concentration, anodization time and current on the superhydrophobic surface were discussed. By PP coating after anodizing, a good superhydrophobic surface was facilely fabricated. The optimum conditions for anodizing were determined by orthogonal experiments. After the aluminium-alloy was grinded with 600# sandpaper, pretreated by 73 g/L hydrochloric acid solution at 1 min, when the concentration of sulfuric acid was 180 g/L, the concentration of oxalic acid was 5 g/L, the concentration of potassium dichromate was 10 g/L, the concentration of chloride sodium was 50 g/L and 63 g/L of glycerol, anodization time was 20 min, and anodization current was 1.2 A/dm2, anodization temperature was 30-35 degrees C, the best micro-nanostructure aluminum alloy films was obtained. On the other hand, the PP with different concentrations was used to the PP with different concentrations was used to coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was achieved by coating PP, and the duration of the superhydrophobic surface was improved by modifying the coat the aluminum alloy surface after anodizing. The results showed that the best superhydrophobicity was surface with high concentration PP. The morphologies of micro/nano-structure superhydrophobic surface were further confirmed by scanning electron microscope (SEM). The material of PP with the low surface free energy combined with the micro/nano-structures of the surface resulted in the superhydrophobicity of the aluminum alloy surface.

  13. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    Science.gov (United States)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-06-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  14. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    Science.gov (United States)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-04-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  15. Effect of machining parameters on surface finish of Inconel 718 in end milling

    Directory of Open Access Journals (Sweden)

    Sarkar Bapi

    2017-01-01

    Full Text Available Surface finish is an important criteria in machining process and selection of proper machining parameters is important to obtain good surface finish. In the present work effects of the machining parameters in end milling of Inconel 718 were investigated. Central composite design was used to design the total number of experiments. A Mathematical model for surface roughness has been developed using response surface methodology. In this study, the influence of cutting parameters such as cutting speed, feed rate and depth of cut on surface roughness was analyzed. The study includes individual effect of cutting parameters on surface roughness as well as their interaction. The analysis of variance (ANOVA was employed to find the validity of the developed model. The results show that depth of cut mostly affected the surface roughness. It is also observed that surface roughness values are comparable in both dry and wet machining conditions.

  16. Slippery liquid-infused porous surfaces fabricated on aluminum as a barrier to corrosion induced by sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Wang, Peng; Lu, Zhou; Zhang, Dun

    2015-01-01

    Highlights: • Slippery liquid-infused porous surfaces (SLIPS) were fabricated over aluminum. • SLIPS depress the adherence of sulfate reducing bacteria in static seawater. • SLIPS inhibit the microbiological corrosion of aluminum in static seawater. • The possible microbiological corrosion protection mechanism of SLIPS is proposed. - Abstract: Microbiological corrosion induced by sulfate reducing bacteria (SRB) is one of the main threatens to the safety of marine structure. To reduce microbiological corrosion, slippery liquid infused porous surfaces (SLIPS) were designed and fabricated on aluminum substrate by constructing rough aluminum oxide layer, followed by fluorination of the rough layer and infiltration with lubricant. The as-fabricated SLIPS were characterized with wettability measurement, SEM and XPS. Their resistances to microbiological corrosion induced by SRB were evaluated with fluorescence microscopy and electrochemical measurement. It was demonstrated that they present high resistance to bacteria adherence and the resultant microbiological corrosion in static seawater

  17. Aluminum surface modification by a non-mass-analyzed nitrogen ion beam

    Science.gov (United States)

    Ohira, Shigeo; Iwaki, Masaya

    Non-mass-analyzed nitrogen ion implantation into polycrystal and single crystal aluminum sheets has been carried out at an accelerating voltage of 90 kV and a dose of 1 × 10 18 N ions/cm 2 using a Zymet implanter model Z-100. The pressure during implantation rose to 10 -3 Pa due to the influence of N gas feeding into the ion source. The characteristics of the surface layers were investigated by means of Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron diffraction (TED), and microscopy (TEM). The AES depth profiling shows a rectangular-like distribution of N atoms and little migration of O atoms near the surface. The high dose N-implantation forms c-axis oriented aluminum nitride (AIN) crystallines, and especially irradiation of Al single crystals with N ions leads to the formation of a hcp AlN single crystal. It is concluded that the high dose N-implantation in Al can result in the formation of AlN at room temperature without any thermal annealing. Furthermore, non-mass-analyzed N-implantation at a pressure of 10 -3 Pa of the nitrogen atmosphere causes the formation of pure AlN single crystals in the Al surface layer and consequently it can be practically used for AlN production.

  18. Effects on Machining on Surface Residual Stress of SA 508 and Austenitic Stainless Steel

    International Nuclear Information System (INIS)

    Lee, Kyoung Soo; Lee, Seong Ho; Park, Chi Yong; Yang, Jun Seok; Lee, Jeong Geun; Park, Jai Hak

    2011-01-01

    Primary water stress corrosion cracking has occurred in dissimilar weld areas in nuclear power plants. Residual stress is a driving force in the crack. Residual stress may be generated by weld or surface machining. Residual stress due to surface machining depends on the machining method, e.g., milling, grinding, or EDM. The stress is usually distributed on or near the surface of the material. We present the measured residual stress for machining on SA 508 and austenitic stainless steels such as TP304 and F316. The residual stress can be tensile or compressive depending on the machining method. The depth and the magnitude of the residual stress depend on the material and the machining method

  19. The Role of Friction Stir Processing (FSP Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Felipe García-Vázquez

    Full Text Available Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP, has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM, scanning electron microscopy (SEM and atomic force microscopy (AFM were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

  20. Preparation of Trivalent Chromium and Rare Earth Composite Conversion Coating on Aluminum Alloy Surface

    Science.gov (United States)

    Huang, Jianzhen

    2018-01-01

    In this paper, the surface conversion film on 6063 aluminum alloy was prepared by chemical plating process with chromium sulfate, lanthanum sulfate and sodium phosphate as film forming agent. The corrosion resistance and surface morphology of the conversion film were analyzed by pitting corrosion test of copper sulfate and SEM. The results show that when Cr2(SO4)3 is 10 g/L, La2(SO4)3 is 2 g/L, Na3PO4 is 8 g/L, pH value is 3, temperature is 40 °C, reaction time is 10 min, the corrosion resistance of the surface conversion film is the best. The conversion coating is light green, composed of Cr, La, P, Al, O and other elements.

  1. A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

    Directory of Open Access Journals (Sweden)

    Po Chun Chen

    2013-01-01

    Full Text Available We proposed fabricating an aluminum microneedle array with a nanochannel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The microneedle array provides a three-dimensional (3D structure that possesses several hundred times more surface area than a traditional nanochannel template. Therefore, the microneedle array can potentially be used in many technology applications. This 3D microneedle array device can not only be used for painless injection or extraction, but also for storage, highly sensitive detection, drug delivery, and microelectrodes. From the calculation we made, the microneedle array not only increases surface area, but also enlarges the capacity of the device. Therefore, the microneedle array can further be used on many detecting, storing, or drug delivering applications.

  2. A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

    International Nuclear Information System (INIS)

    Chen, P.Ch.; Zou, J.; Hsieh, Sh.J.; Chen, Ch.Ch.

    2013-01-01

    We proposed fabricating an aluminum micro needle array with a nano channel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The micro needle array provides a three-dimensional (3D) structure that possesses several hundred times more surface area than a traditional nano channel template. Therefore, the micro needle array can potentially be used in many technology applications. This 3D micro needle array device can not only be used for painless injection or extraction, but also for storage, highly sensitive detection, drug delivery, and microelectrodes. From the calculation we made, the micro needle array not only increases surface area, but also enlarges the capacity of the device. Therefore, the micro needle array can further be used on many detecting, storing, or drug delivering applications.

  3. Application for vibration monitoring of aspheric surface machining based on wireless sensor networks

    Science.gov (United States)

    Han, Chun Guang; Guo, Yin Biao; Jiang, Chen

    2010-05-01

    Any kinds of tiny vibration of machine tool parts will have a great influence on surface quality of the workpiece at ultra-precise machining process of aspheric surface. At present the major way for decreasing influence of vibration is machining compensation technology. Therefore it is important for machining compensation control to acquire and transmit these vibration signals effectively. This paper presents a vibration monitoring system of aspheric surface machining machine tool based on wireless sensor networks (WSN). Some key issues of wireless sensor networks for vibration monitoring system of aspheric surface machining are discussed. The reliability of data transmission, network communication protocol and synchronization mechanism of wireless sensor networks are studied for the vibration monitoring system. The proposed system achieves multi-sensors vibration monitoring involving the grinding wheel, the workpiece and the workbench spindle. The wireless transmission of vibration signals is achieved by the combination with vibration sensor nodes and wireless network. In this paper, these vibration sensor nodes are developed. An experimental platform is structured which employs wireless sensor networks to the vibration monitoring system in order to test acquisition and wireless transmission of vibration signal. The test results show that the proposed system can achieve vibration data transmission effectively and reliability and meet the monitoring requirements of aspheric surface machining machine tool.

  4. Image potential resonances of the aluminum (100) surface; Bildpotentialresonanzen der Aluminium-(100)-Oberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Matthias

    2011-07-08

    Image-potential resonances on the (100) surface of pure Aluminum are investigated experimentally and theoretically. The experiments are conducted both energy- and time-resolved using the method of two-photon photoemission spectroscopy. The main attention of the theoretical examination and extensive numerical calculations is devoted to the interaction between surface and bulk states. Image-potential resonances on Al(100) are a system in which a complete series of discrete Rydberg states strongly couples to a continuum of states. As a simple metal it also provides a good opportunity to test theoretical models of the structure of the potential at metal surfaces. This work represents the first high-resolution investigation of image-potential resonances with such strong resonance character. For the first time, it is demonstrated experimentally that isolated image-potential resonances exist on an Aluminum surface. On the (100) surface of Aluminum the second through fifth image-potential resonance are resolved and both, their energies and lifetimes are measured. The binding energies of the image-potential resonances form a Rydberg series of states {epsilon}{sub n}=-(0,85 eV)/((n+a){sup 2}). Within the accuracy of the measurement it is not necessary to introduce a quantum defect a (a=0.022{+-}0.035). Using angle-resolved two-photon photoemission spectroscopy the effective mass of electrons in the second image-potential resonance is measured to 1.01{+-}0.11 electron masses. The lifetimes of the resonances increase as {tau}{sub n} = (1.0{+-}0.2)fs.n{sup 3} starting from n=2. Calculations using the density matrix formalism show that the experimentally observed lifetimes can be explained well by electrons decaying into the bulk. The effect of resonance trapping leads to extended lifetimes in the process. Contrary to common theoretical models of image-potential states at metal surfaces the first image-potential resonance cannot be observed in two-photon photoemission on Al(100

  5. Effect of machining parameters on surface integrity of silicon carbide ceramic using end electric discharge milling and mechanical grinding hybrid machining

    International Nuclear Information System (INIS)

    Ji, Renjie; Liu, Yonghong; Zhang, Yanzhen; Cai, Baoping; Li, Xiaopeng; Zheng, Chao

    2013-01-01

    A novel hybrid process that integrates end electric discharge (ED) milling and mechanical grinding is proposed. The process is able to effectively machine a large surface area on SiC ceramic with good surface quality and fine working environmental practice. The polarity, pulse on-time, and peak current are varied to explore their effects on the surface integrity, such as surface morphology, surface roughness, micro-cracks, and composition on the machined surface. The results show that positive tool polarity, short pulse on-time, and low peak current cause a fine surface finish. During the hybrid machining of SiC ceramic, the material is mainly removed by end ED milling at rough machining mode, whereas it is mainly removed by mechanical grinding at finish machining mode. Moreover, the material from the tool can transfer to the workpiece, and a combination reaction takes place during machining.

  6. Thermal effects in equilibrium surface segregation in a copper/10-atomic-percent-aluminum alloy using Auger electron spectroscopy

    Science.gov (United States)

    Ferrante, J.

    1972-01-01

    Equilibrium surface segregation of aluminum in a copper-10-atomic-percent-aluminum single crystal alloy oriented in the /111/ direction was demonstrated by using Auger electron spectroscopy. This crystal was in the solid solution range of composition. Equilibrium surface segregation was verified by observing that the aluminum surface concentration varied reversibly with temperature in the range 550 to 850 K. These results were curve fitted to an expression for equilibrium grain boundary segregation and gave a retrieval energy of 5780 J/mole (1380 cal/mole) and a maximum frozen-in surface coverage three times the bulk layer concentration. Analyses concerning the relative merits of sputtering calibration and the effects of evaporation are also included.

  7. AFM surface imaging of AISI D2 tool steel machined by the EDM process

    International Nuclear Information System (INIS)

    Guu, Y.H.

    2005-01-01

    The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM

  8. AFM surface imaging of AISI D2 tool steel machined by the EDM process

    Science.gov (United States)

    Guu, Y. H.

    2005-04-01

    The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM.

  9. FDTD analysis of Aluminum/a-Si:H surface plasmon waveguides

    Science.gov (United States)

    Lourenço, Paulo; Fantoni, Alessandro; Fernandes, Miguel; Vygranenko, Yuri; Vieira, Manuela

    2018-02-01

    The large majority of surface plasmon resonance based devices use noble metals, namely gold or silver, in their manufacturing process. These metals present low resistivity, which leads to low optical losses in the visible and near infrared spectrum ranges. Gold shows high environmental stability, which is essential for long-term operation, and silver's lower stability can be overcome through the deposition of an alumina layer, for instance. However, their high cost is a limiting factor if the intended target is large scale manufacturing. In this work, it is considered a cost-effective approach through the selection of aluminum as the plasmonic material and hydrogenated amorphous silicon instead of its crystalline counterpart. This surface plasmon resonance device relies on Fano resonance to improve its response to refractive index deviations of the surrounding environment. Fano resonance is highly sensitive to slight changes of the medium, hence the reason we incorporated this interference phenomenon in the proposed device. We report the results obtained when conducting Finite-Difference Time Domain algorithm based simulations on this metal-dielectric-metal structure when the active metal is aluminum, gold and silver. Then, we evaluate their sensitivity, detection accuracy and resolution, and the obtained results for our proposed device show good linearity and similar parameter performance as the ones obtained when using gold or silver as plasmonic materials.

  10. New roots to formation of nanostructures on glass surface through anodic oxidation of sputtered aluminum

    Directory of Open Access Journals (Sweden)

    Satoru Inoue, Song-Zhu Chu, Kenji Wada, Di Li and Hajime Haneda

    2003-01-01

    Full Text Available New processes for the preparation of nanostructure on glass surfaces have been developed through anodic oxidation of sputtered aluminum. Aluminum thin film sputtered on a tin doped indium oxide (ITO thin film on a glass surface was converted into alumina by anodic oxidation. The anodic alumina gave nanometer size pore array standing vertically on the glass surface. Kinds of acids used in the anodic oxidation changed the pore size drastically. The employment of phosphoric acid solution gave several tens nanometer size pores. Oxalic acid cases produced a few tens nanometer size pores and sulfuric acid solution provided a few nanometer size pores. The number of pores in a unit area could be changed with varying the applied voltage in the anodization and the pore sizes could be increased by phosphoric acid etching. The specimen consisting of a glass substrate with the alumina nanostructures on the surface could transmit UV and visible light. An etched specimen was dipped in a TiO2 sol solution, resulting in the impregnation of TiO2 sol into the pores of alumina layer. The TiO2 sol was heated at ~400 °C for 2 h, converting into anatase phase TiO2. The specimens possessing TiO2 film on the pore wall were transparent to the light in UV–Visible region. The electro deposition technique was applied to the introduction of Ni metal into pores, giving Ni nanorod array on the glass surface. The removal of the barrier layer alumina at the bottom of the pores was necessary to attain smooth electro deposition of Ni. The photo catalytic function of the specimens possessing TiO2 nanotube array was investigated in the decomposition of acetaldehyde gas under the irradiation of UV light, showing that the rate of the decomposition was quite large.

  11. Towards efficient 5-axis flank CNC machining of free-form surfaces via fitting envelopes of surfaces of revolution

    OpenAIRE

    Bo P.; Bartoň M.; Plakhotnik D.; Pottmann H.

    2016-01-01

    We introduce a new method that approximates free-form surfaces by envelopes of one-parameter motions of surfaces of revolution. In the context of 5-axis computer numerically controlled (CNC) machining, we propose a flank machining methodology which is a preferable scallop-free scenario when the milling tool and the machined free-form surface meet tangentially along a smooth curve. We seek both an optimal shape of the milling tool as well as its optimal path in 3D space and propose an optimiza...

  12. High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Pogorelko, Victor V., E-mail: vik_ko83@mail.ru [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation); Mayer, Alexander E., E-mail: mayer@csu.ru [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation); Krasnikov, Vasiliy S., E-mail: vas.krasnikov@gmail.com [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation)

    2016-12-30

    Highlights: • High-speed nanoparticle impact induces shock waves and intensive plastic deformation. • Lattice orientation strongly influences on the deformation degree. • Plastic deformation goes through nucleation, growth and separation of semi-loops. • Medium impact energy and elevated temperature are optimal for high-quality coating. • High impact velocity and room temperature lead to plastic deformation and coating. - Abstract: We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2–22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the

  13. High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

    International Nuclear Information System (INIS)

    Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

    2016-01-01

    Highlights: • High-speed nanoparticle impact induces shock waves and intensive plastic deformation. • Lattice orientation strongly influences on the deformation degree. • Plastic deformation goes through nucleation, growth and separation of semi-loops. • Medium impact energy and elevated temperature are optimal for high-quality coating. • High impact velocity and room temperature lead to plastic deformation and coating. - Abstract: We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2–22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the

  14. Cladding the inside surface of a 3 1/4 in. ID Zircaloy-2 pressure tube with 1S aluminum

    International Nuclear Information System (INIS)

    Watson, R.D.

    1966-09-01

    A hot-press sizing technique has been developed for cladding the inside surface of Zircaloy-2 pressure tubes with 1S aluminum. The process is performed in air with the Zircaloy-2 and aluminum at a temperature of approximately 950 o F. A controlled atmosphere is not required, either during preheating or while the cladding is being applied. Tubes 30 inches long and 3 1/4 inches ID have been coated with 1S aluminum in thicknesses ranging from 0.005 inches to more than 0.02 inches; tubes longer than 30 inches have not been attempted. The lining of aluminum is firmly attached to the Zircaloy-2 at all points in the tube but the bond strength varies considerably - from. 6500 to 28000 lbf/in 2 . This work is the subject of Canadian Patent Application No. 955,358 filed March 21, 1966. (author)

  15. New Method to Characterize Degradation of First Surface Aluminum Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, F.; Heller, P.; Meyen, S.; Pitz-Paal, R.; Kennedy, C.; Fernandez-Garcia, A.; Schmucker, M.

    2010-10-01

    This paper reports the development of a new optical instrument capable of characterizing the aging process of enhanced first surface aluminum reflectors for concentrating solar power (CSP) application. Samples were exposed outdoors at different sites and in accelerated exposure tests. All samples exposed outdoors showed localized corrosion spots. Degradation originated from points of damage in the protective coating, but propagated underneath the protective coating. The degraded samples were analyzed with a microscope and with a newly designed space-resolved specular reflectometer (SR)2 that is capable of optically detecting and characterizing the corrosion spots. The device measures the specular reflectance at three acceptance angles and the wavelengths with spatial resolution using a digital camera's CMOS sensor. It can be used to measure the corrosion growth rate during outdoor and accelerated exposure tests. These results will allow a correlation between the degraded mirror surface and its specular reflectance.

  16. Sparking-out optimization while surface grinding aluminum alloy 1933T2 parts using fuzzy logic

    Science.gov (United States)

    Soler, Ya I.; Salov, V. M.; Kien Nguyen, Chi

    2018-03-01

    The article presents the results of a search for optimal sparing-out strokes when surface grinding aluminum parts by high-porous wheels Norton of black silicon carbide 37C80K12VP using fuzzy logic. The topography of grinded surface is evaluated according to the following parameters: roughness – Ra, Rmax, Sm; indicators of flatness deviation – EFEmax, EFEa, EFEq; microhardness HV, each of these parameters is represented by two measures of position and dispersion. The simulation results of fuzzy logic in the Matlab medium establish that during the grinding of alloy 1933T2, the best integral performance evaluation of sparking-out was given to two double-strokes (d=0.827) and the worst – to three ones (d=0.405).

  17. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Jalili, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of)

    2015-02-15

    Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

  18. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    International Nuclear Information System (INIS)

    Jalili, M.; Rostami, M.; Ramezanzadeh, B.

    2015-01-01

    Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties

  19. Machining of bone: Analysis of cutting force and surface roughness by turning process.

    Science.gov (United States)

    Noordin, M Y; Jiawkok, N; Ndaruhadi, P Y M W; Kurniawan, D

    2015-11-01

    There are millions of orthopedic surgeries and dental implantation procedures performed every year globally. Most of them involve machining of bones and cartilage. However, theoretical and analytical study on bone machining is lagging behind its practice and implementation. This study views bone machining as a machining process with bovine bone as the workpiece material. Turning process which makes the basis of the actually used drilling process was experimented. The focus is on evaluating the effects of three machining parameters, that is, cutting speed, feed, and depth of cut, to machining responses, that is, cutting forces and surface roughness resulted by the turning process. Response surface methodology was used to quantify the relation between the machining parameters and the machining responses. The turning process was done at various cutting speeds (29-156 m/min), depths of cut (0.03 -0.37 mm), and feeds (0.023-0.11 mm/rev). Empirical models of the resulted cutting force and surface roughness as the functions of cutting speed, depth of cut, and feed were developed. Observation using the developed empirical models found that within the range of machining parameters evaluated, the most influential machining parameter to the cutting force is depth of cut, followed by feed and cutting speed. The lowest cutting force was obtained at the lowest cutting speed, lowest depth of cut, and highest feed setting. For surface roughness, feed is the most significant machining condition, followed by cutting speed, and with depth of cut showed no effect. The finest surface finish was obtained at the lowest cutting speed and feed setting. © IMechE 2015.

  20. Multi-Parameter Analysis of Surface Finish in Electro-Discharge Machining of Tool Steels

    Directory of Open Access Journals (Sweden)

    Cornelia Victoria Anghel

    2006-10-01

    Full Text Available The paper presents a multi- parameter analysis of surface finish imparted to tool-steel plates by electro-discharge machining (EDM is presented. The interrelationship between surface texture parameters and process parameters is emphasized. An increased number of parameters is studied including amplitude, spacing, hybrid and fractal parameters,, as well. The correlation of these parameters with the machining conditions is investigated. Observed characteristics become more pronounced, when intensifying machining conditions. Close correlation exists between certain surface finish parameters and EDM input variables and single and multiple statistical regression models are developed.

  1. Aluminum metal surface cleaning and activation by atmospheric-pressure remote plasma

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, J., E-mail: jmespadero@uco.es; Bravo, J.A.; Calzada, M.D.

    2017-06-15

    Highlights: • Atmospheric-pressure postdischarges have been applied on aluminium surfaces. • The outer hydrocarbon layer is reduced by the action of the postdischarge. • The treatment promotes the appearance of hydrophilic OH radicals in the surface. • Effectivity for distances up to 5 cm allows for treating irregular surfaces. • Ageing in air due to the disappearance of OH radicals has been reported. - Abstract: The use of the remote plasma (postdischarge) of argon and argon-nitrogen microwave plasmas for cleaning and activating the surface of metallic commercial aluminum samples has been studied. The influence of the nitrogen content and the distance between the treated samples and the end of the discharge on the hydrophilicity and the surface energy has been analyzed by means of the sessile drop technique and the Owens-Wendt method. A significant increase in the hydrophilicity has been noted in the treated samples, together with an increase in the surface energy from values around 37 mJ/m{sup 2} to 77 mJ/m{sup 2}. Such increase weakly depends on the nitrogen content of the discharge, and the effectivity of the treatment extends to distances up to 5 cm from the end of the discharge, much longer than those reported in other plasma-based treatments. The analysis of the treated samples using X-ray photoelectron spectroscopy reveals that such increase in the surface energy takes place due to a reduction of the carbon content and an increase in the amount of OH radicals in the surface. These radicals tend to disappear within 24–48 h after the treatment when the samples are stored in contact with ambient air, resulting in the ageing of the treated surface and a partial retrieval of the hydrophobicity of the surface.

  2. Growth and Breakdown of Surface Films and Localized Corrosion of Aluminum in Concentrated Chloride Media

    National Research Council Canada - National Science Library

    Lee, Jiajing

    1994-01-01

    ...) and mechanical stress for aluminum and titanium alloys in aggressive corrosion environments. This report presents results of some very preliminary experiments on aluminum alloys and titanium during anodic dissolution in chloride media...

  3. Optimization of Surface Finish in Turning Operation by Considering the Machine Tool Vibration using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Muhammad Munawar

    2012-01-01

    Full Text Available Optimization of surface roughness has been one of the primary objectives in most of the machining operations. Poor control on the desired surface roughness generates non conforming parts and results into increase in cost and loss of productivity due to rework or scrap. Surface roughness value is a result of several process variables among which machine tool condition is one of the significant variables. In this study, experimentation was carried out to investigate the effect of machine tool condition on surface roughness. Variable used to represent machine tool\\'s condition was vibration amplitude. Input parameters used, besides vibration amplitude, were feed rate and insert nose radius. Cutting speed and depth of cut were kept constant. Based on Taguchi orthogonal array, a series of experimentation was designed and performed on AISI 1040 carbon steel bar at default and induced machine tool\\'s vibration amplitudes. ANOVA (Analysis of Variance, revealed that vibration amplitude and feed rate had moderate effect on the surface roughness and insert nose radius had the highest significant effect on the surface roughness. It was also found that a machine tool with low vibration amplitude produced better surface roughness. Insert with larger nose radius produced better surface roughness at low feed rate.

  4. Standard Methods of Analysis of Sulfochromate Etch Solution Used in Surface Preparation of Aluminum

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2012-01-01

    1.1 These methods offer a means for controlling the effectiveness of the etchant which is normally used for preparing the surface of aluminum alloys for subsequent adhesive bonding. As the etchant reacts with the aluminum, hexavalent chromium is converted to trivalent chromium; a measure of the two and the difference can be used to determine the amount of dichromate used. 1.2 The sulfochromate solution can be replenished by restoring the sodium dichromate and the sulfuric acid to the original formulation levels. The lower limit of usefulness will vary depending upon solution storage, adhesives used, critical nature of bond capability, variety of metals processed, etc. and should be determined. Replenishment will be limited to the number of times the chemical ingredients can be restored and maintained to the required levels and should be determined by the user. Sludge collecting in the bottom of a tank should be minimized by periodic removal of sludge. For some applications, the hexavalent chromium should not ...

  5. Measurement of the surface charge accumulation using anodic aluminum oxide(AAO) structure in an inductively coupled plasma

    Science.gov (United States)

    Park, Ji-Hwan; Oh, Seung-Ju; Lee, Hyo-Chang; Kim, Yu-Sin; Kim, Young-Cheol; Kim, June Young; Ha, Chang-Seoung; Kwon, Soon-Ho; Lee, Jung-Joong; Chung, Chin-Wook

    2014-10-01

    As the critical dimension of the nano-device shrinks, an undesired etch profile occurs during plasma etch process. One of the reasons is the local electric field due to the surface charge accumulation. To demonstrate the surface charge accumulation, an anodic aluminum oxide (AAO) membrane which has high aspect ratio is used. The potential difference between top electrode and bottom electrode in an anodic aluminum oxide contact structure is measured during inductively coupled plasma exposure. The voltage difference is changed with external discharge conditions, such as gas pressure, input power, and gas species and the result is analyzed with the measured plasma parameters.

  6. Optimal condition for fabricating superhydrophobic Aluminum surfaces with controlled anodizing processes

    Science.gov (United States)

    Saffari, Hamid; Sohrabi, Beheshteh; Noori, Mohammad Reza; Bahrami, Hamid Reza Talesh

    2018-03-01

    A single step anodizing process is used to produce micro-nano structures on Aluminum (1050) substrates with sulfuric acid as electrolyte. Therefore, surface energy of the anodized layer is reduced using stearic acid modification. Undoubtedly, effects of different parameters including anodizing time, electrical current, and type and concentration of electrolyte on the final contact angle are systemically studied and optimized. Results show that anodizing current of 0.41 A, electrolyte (sulfuric acid) concentration of 15 wt.% and anodizing time of 90 min are optimal conditions which give contact angle as high as 159.2° and sliding angle lower than 5°. Moreover, the study reveals that adding oxalic acid to the sulfuric acid cannot enhance superhydrophobicity of the samples. Also, scanning electron microscopy images of samples show that irregular (bird's nest) structures present on the surface instead of high-ordered honeycomb structures expecting from normal anodizing process. Additionally, X-ray diffraction analysis of the samples shows that only amorphous structures present on the surface. The Brunauer-Emmett-Teller (BET) specific surface area of the anodized layer is 2.55 m2 g-1 in optimal condition. Ultimately, the surface keeps its hydrophobicity in air and deionized water (DIW) after one week and 12 weeks, respectively.

  7. Chip formation and surface integrity in high-speed machining of hardened steel

    Science.gov (United States)

    Kishawy, Hossam Eldeen A.

    Increasing demands for high production rates as well as cost reduction have emphasized the potential for the industrial application of hard turning technology during the past few years. Machining instead of grinding hardened steel components reduces the machining sequence, the machining time, and the specific cutting energy. Hard turning Is characterized by the generation of high temperatures, the formation of saw toothed chips, and the high ratio of thrust to tangential cutting force components. Although a large volume of literature exists on hard turning, the change in machined surface physical properties represents a major challenge. Thus, a better understanding of the cutting mechanism in hard turning is still required. In particular, the chip formation process and the surface integrity of the machined surface are important issues which require further research. In this thesis, a mechanistic model for saw toothed chip formation is presented. This model is based on the concept of crack initiation on the free surface of the workpiece. The model presented explains the mechanism of chip formation. In addition, experimental investigation is conducted in order to study the chip morphology. The effect of process parameters, including edge preparation and tool wear on the chip morphology, is studied using Scanning Electron Microscopy (SEM). The dynamics of chip formation are also investigated. The surface integrity of the machined parts is also investigated. This investigation focusses on residual stresses as well as surface and sub-surface deformation. A three dimensional thermo-elasto-plastic finite element model is developed to predict the machining residual stresses. The effect of flank wear is introduced during the analysis. Although residual stresses have complicated origins and are introduced by many factors, in this model only the thermal and mechanical factors are considered. The finite element analysis demonstrates the significant effect of the heat generated

  8. Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

    International Nuclear Information System (INIS)

    Zou Yang; Cai Jie; Wan Ming-Zhen; Lv Peng; Guan Qing-Feng

    2011-01-01

    The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1–1 μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials. (condensed matter: structure, mechanical and thermal properties)

  9. An easy and environmentally-friendly approach to superamphiphobicity of aluminum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Deng, R. [School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China); Hu, Y.M., E-mail: yongmaohu@163.com [College of Engineering, Dali University, Dali 671003 (China); Wang, L.; Li, Zh.H.; Shen, T. [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Zhu, Y., E-mail: zhuyan@kmust.edu.cn [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Xiang, J.Zh., E-mail: jzhxiang@ynu.edu.cn [School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China)

    2017-04-30

    Highlights: • Superamphiphobic Al surfaces were achieved via an approach of chemical etching and low surface energy material modification. • The process of chemical etching and hot water bathing were optimized to obtain desirable hierarchical micro/nanoscale structures. • The surface morphology, chemistry and wetting properties of the as-prepared aluminum surfaces were characterized and discussed. • The mechanical robustness and chemical stability of the as-prepared superamphiphobic Al surfaces were tested and evaluated. - Abstract: Superamphiphobic Al surfaces were achieved via an easy and environmentally-friendly approach. Aqueous mixed solution of 0.7 M CuSO{sub 4} and 1 M NaCl was used to etch polished Al surfaces to fabricate a rough morphology distributed with microscale step-like pits. The uniformly distributed nanoscale petals covered on the microscale pits were obtained by subsequent 96 °C hot deionized water bathing for 13 min. Thus, the hierarchical micro/nanometer scale roughness was formed which provided the structural basic of superamphiphobic Al surfaces. By 1H, 1H, 2H, 2H-Perfluorodecyl-triethoxysilane (PFDTS) derivatization, desirable superamphiphobic Al surfaces were achieved with the highest static contact angles of 162° for water, 156° for peanut oil, respectively. Meanwhile, the sliding angles were lower than 10° for both water and peanut oil droplets. The as-prepared Al surfaces were investigated by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and optical contact angle measurements. The FE-SEM images of as-prepared Al surfaces showed a hierarchical micro/nanometer scale morphology. XPS analyses demonstrated the PFDTS derivitization on Al surfaces. The superamphiphobic Al surfaces presented good mechanical durability and chemical stability which have a wide range of applications in fields such as self-cleaning, anti-icing, anti

  10. An easy and environmentally-friendly approach to superamphiphobicity of aluminum surfaces

    International Nuclear Information System (INIS)

    Deng, R.; Hu, Y.M.; Wang, L.; Li, Zh.H.; Shen, T.; Zhu, Y.; Xiang, J.Zh.

    2017-01-01

    Highlights: • Superamphiphobic Al surfaces were achieved via an approach of chemical etching and low surface energy material modification. • The process of chemical etching and hot water bathing were optimized to obtain desirable hierarchical micro/nanoscale structures. • The surface morphology, chemistry and wetting properties of the as-prepared aluminum surfaces were characterized and discussed. • The mechanical robustness and chemical stability of the as-prepared superamphiphobic Al surfaces were tested and evaluated. - Abstract: Superamphiphobic Al surfaces were achieved via an easy and environmentally-friendly approach. Aqueous mixed solution of 0.7 M CuSO 4 and 1 M NaCl was used to etch polished Al surfaces to fabricate a rough morphology distributed with microscale step-like pits. The uniformly distributed nanoscale petals covered on the microscale pits were obtained by subsequent 96 °C hot deionized water bathing for 13 min. Thus, the hierarchical micro/nanometer scale roughness was formed which provided the structural basic of superamphiphobic Al surfaces. By 1H, 1H, 2H, 2H-Perfluorodecyl-triethoxysilane (PFDTS) derivatization, desirable superamphiphobic Al surfaces were achieved with the highest static contact angles of 162° for water, 156° for peanut oil, respectively. Meanwhile, the sliding angles were lower than 10° for both water and peanut oil droplets. The as-prepared Al surfaces were investigated by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and optical contact angle measurements. The FE-SEM images of as-prepared Al surfaces showed a hierarchical micro/nanometer scale morphology. XPS analyses demonstrated the PFDTS derivitization on Al surfaces. The superamphiphobic Al surfaces presented good mechanical durability and chemical stability which have a wide range of applications in fields such as self-cleaning, anti-icing, anti-corrosion, oil

  11. Detecting Milling Deformation in 7075 Aluminum Alloy Aeronautical Monolithic Components Using the Quasi-Symmetric Machining Method

    Directory of Open Access Journals (Sweden)

    Qiong Wu

    2016-04-01

    Full Text Available The deformation of aeronautical monolithic components due to CNC machining is a bottle-neck issue in the aviation industry. The residual stress releases and redistributes in the process of material removal, and the distortion of the monolithic component is generated. The traditional one-side machining method will produce oversize deformation. Based on the three-stage CNC machining method, the quasi-symmetric machining method is developed in this study to reduce deformation by symmetry material removal using the M-symmetry distribution law of residual stress. The mechanism of milling deformation due to residual stress is investigated. A deformation experiment was conducted using traditional one-side machining method and quasi-symmetric machining method to compare with finite element method (FEM. The deformation parameters are validated by comparative results. Most of the errors are within 10%. The reason for these errors is determined to improve the reliability of the method. Moreover, the maximum deformation value of using quasi-symmetric machining method is within 20% of that of using the traditional one-side machining method. This result shows the quasi-symmetric machining method is effective in reducing deformation caused by residual stress. Thus, this research introduces an effective method for reducing the deformation of monolithic thin-walled components in the CNC milling process.

  12. Pullulan as a potent green inhibitor for corrosion mitigation of aluminum composite: Electrochemical and surface studies.

    Science.gov (United States)

    B P, Charitha; Rao, Padmalatha

    2018-06-01

    This work emphasizes the corrosion inhibition ability of pullulan, an environmentally benign fungal polysaccharide on acid corrosion of 6061Aluminum-15% (v) SiC (P) composite material (Al-CM). The electrochemical measurements such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) studies were carried out for the corrosion inhibition studies. Conditions were optimized to obtain maximum inhibition efficiency, by performing the experiment at varying concentrations of inhibitor, in the temperature range of 308K- 323K. Surface morphology studies were done to reaffirm the adsorption of inhibitor on the surface of composite material. Pullulan acted as mixed type of inhibitor with a maximum efficiency of 89% at 303K for the addition of 1.0 gL -1 of inhibitor. Evaluation of kinetic and thermodynamic parameters revealed that inhibitor underwent physical adsorption onto the surface of Al-CM and obeyed Freundlich adsorption isotherm. The surface characterization like SEM-EDX, AFM confirmed the adsorption of pullulan molecule. Pullulan can be considered as effective, eco friendly green inhibitor for the corrosion control of Al-CM. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Defect detection and classification of machined surfaces under multiple illuminant directions

    Science.gov (United States)

    Liao, Yi; Weng, Xin; Swonger, C. W.; Ni, Jun

    2010-08-01

    Continuous improvement of product quality is crucial to the successful and competitive automotive manufacturing industry in the 21st century. The presence of surface porosity located on flat machined surfaces such as cylinder heads/blocks and transmission cases may allow leaks of coolant, oil, or combustion gas between critical mating surfaces, thus causing damage to the engine or transmission. Therefore 100% inline inspection plays an important role for improving product quality. Although the techniques of image processing and machine vision have been applied to machined surface inspection and well improved in the past 20 years, in today's automotive industry, surface porosity inspection is still done by skilled humans, which is costly, tedious, time consuming and not capable of reliably detecting small defects. In our study, an automated defect detection and classification system for flat machined surfaces has been designed and constructed. In this paper, the importance of the illuminant direction in a machine vision system was first emphasized and then the surface defect inspection system under multiple directional illuminations was designed and constructed. After that, image processing algorithms were developed to realize 5 types of 2D or 3D surface defects (pore, 2D blemish, residue dirt, scratch, and gouge) detection and classification. The steps of image processing include: (1) image acquisition and contrast enhancement (2) defect segmentation and feature extraction (3) defect classification. An artificial machined surface and an actual automotive part: cylinder head surface were tested and, as a result, microscopic surface defects can be accurately detected and assigned to a surface defect class. The cycle time of this system can be sufficiently fast that implementation of 100% inline inspection is feasible. The field of view of this system is 150mm×225mm and the surfaces larger than the field of view can be stitched together in software.

  14. Influence of edge radius of sintered-carbide tip on roughness of machined surface

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2013-01-01

    Full Text Available Increasing of cutting speed and thus increasing labour productivity is observed as a current trend in engineering production. This effort results to development of new cutting materials which are more capable to resist increased requirements on machined surface as well as operating life of the instrument. Nowadays, the most widely used materials used for cutting instruments are sintered carbides which are alloyed by other metals. The goal of this paper is to analyse change in quality of machined surface depending on the change of cutting conditions. For cutting operation, there were used a milling cutter high-speed steel 90 (HSS and removable sintered-carbide tips with different radius. Steel 12 050 hardened for 17 HRC was used as a machined material. Firstly, hardness of machined as well as machining materials was analysed. Further, metallographic analysis and measurement of microhardness of the individual structure phases was processed. Cutting conditions of both instruments were selected depending on the machined material. Surface roughness indicates the quality of machined surface.

  15. 40 CFR 63.5752 - How do I calculate the organic HAP content of aluminum recreational boat surface coatings?

    Science.gov (United States)

    2010-07-01

    ... Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5752 How do I calculate... fraction of organic HAP in coating i, kilograms of organic HAP per kilogram of coating. p = number of..., activator, or additive k, kilograms per liter. Wk= mass fraction of organic HAP in thinner, activator, or...

  16. Experimental/Computational Approach to Accommodation Coefficients and its Application to Noble Gases on Aluminum Surface (Preprint)

    Science.gov (United States)

    2009-02-03

    computational approach to accommodation coefficients and its application to noble gases on aluminum surface Nathaniel Selden Uruversity of Southern Cahfornia, Los ...8217 ,. 0.’ a~ .......,..,P. • " ,,-0, "p"’U".. ,Po"D.’ 0.’P.... uro . P." FIG. 5: Experimental and computed radiometri~ force for argon (left), xenon

  17. Aluminum agglomeration involving the second mergence of agglomerates on the solid propellants burning surface: Experiments and modeling

    Science.gov (United States)

    Ao, Wen; Liu, Xin; Rezaiguia, Hichem; Liu, Huan; Wang, Zhixin; Liu, Peijin

    2017-07-01

    The agglomeration of aluminum particles usually occurs on the burning surface of aluminized composite propellants. It leads to low propellant combustion efficiency and high two-phase flow losses. To reach a thorough understanding of aluminum agglomeration behaviors, agglomeration processes, and particles size distribution of Al/AP/RDX/GAP propellants were studied by using a cinephotomicrography experimental technique, under 5 MPa. Accumulation, aggregation, and agglomeration phenomena of aluminum particles have been inspected, as well as the flame asymmetry of burning agglomerates. Results reveals that the dependency of the mean and the maximum agglomeration diameter to the burning rate and the virgin aluminum size have the same trend. A second-time mergence of multiple agglomerates on the burning surface is unveiled. Two typical modes of second mergence are concluded, based upon vertical and level movement of agglomerates, respectively. The latter mode is found to be dominant and sometimes a combination of the two modes may occur. A new model of aluminum agglomeration on the burning surface of composite propellants is derived to predict the particulates size distribution with a low computational amount. The basic idea is inspired from the well-known pocket models. The pocket size of the region formed by adjacent AP particles is obtained through scanning electron microscopy of the propellant cross-section coupled to an image processing method. The second mergence mechanism, as well as the effect of the burning rate on the agglomeration processes, are included in the present model. The mergence of two agglomerates is prescribed to occur only if their separation distance is less than a critical value. The agglomerates size distribution resulting from this original model match reasonably with the experimental data. Moreover, the present model gives superior results for mean agglomeration diameter compared to common empirical and pocket models. The average prediction

  18. Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

    Science.gov (United States)

    Chen, Jianbo

    This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell

  19. ANN Surface Roughness Optimization of AZ61 Magnesium Alloy Finish Turning: Minimum Machining Times at Prime Machining Costs

    Directory of Open Access Journals (Sweden)

    Adel Taha Abbas

    2018-05-01

    Full Text Available Magnesium alloys are widely used in aerospace vehicles and modern cars, due to their rapid machinability at high cutting speeds. A novel Edgeworth–Pareto optimization of an artificial neural network (ANN is presented in this paper for surface roughness (Ra prediction of one component in computer numerical control (CNC turning over minimal machining time (Tm and at prime machining costs (C. An ANN is built in the Matlab programming environment, based on a 4-12-3 multi-layer perceptron (MLP, to predict Ra, Tm, and C, in relation to cutting speed, vc, depth of cut, ap, and feed per revolution, fr. For the first time, a profile of an AZ61 alloy workpiece after finish turning is constructed using an ANN for the range of experimental values vc, ap, and fr. The global minimum length of a three-dimensional estimation vector was defined with the following coordinates: Ra = 0.087 μm, Tm = 0.358 min/cm3, C = $8.2973. Likewise, the corresponding finish-turning parameters were also estimated: cutting speed vc = 250 m/min, cutting depth ap = 1.0 mm, and feed per revolution fr = 0.08 mm/rev. The ANN model achieved a reliable prediction accuracy of ±1.35% for surface roughness.

  20. ANN Surface Roughness Optimization of AZ61 Magnesium Alloy Finish Turning: Minimum Machining Times at Prime Machining Costs.

    Science.gov (United States)

    Abbas, Adel Taha; Pimenov, Danil Yurievich; Erdakov, Ivan Nikolaevich; Taha, Mohamed Adel; Soliman, Mahmoud Sayed; El Rayes, Magdy Mostafa

    2018-05-16

    Magnesium alloys are widely used in aerospace vehicles and modern cars, due to their rapid machinability at high cutting speeds. A novel Edgeworth⁻Pareto optimization of an artificial neural network (ANN) is presented in this paper for surface roughness ( Ra ) prediction of one component in computer numerical control (CNC) turning over minimal machining time ( T m ) and at prime machining costs ( C ). An ANN is built in the Matlab programming environment, based on a 4-12-3 multi-layer perceptron (MLP), to predict Ra , T m , and C , in relation to cutting speed, v c , depth of cut, a p , and feed per revolution, f r . For the first time, a profile of an AZ61 alloy workpiece after finish turning is constructed using an ANN for the range of experimental values v c , a p , and f r . The global minimum length of a three-dimensional estimation vector was defined with the following coordinates: Ra = 0.087 μm, T m = 0.358 min/cm³, C = $8.2973. Likewise, the corresponding finish-turning parameters were also estimated: cutting speed v c = 250 m/min, cutting depth a p = 1.0 mm, and feed per revolution f r = 0.08 mm/rev. The ANN model achieved a reliable prediction accuracy of ±1.35% for surface roughness.

  1. Influence of Wire Electrical Discharge Machining (WEDM) process parameters on surface roughness

    Science.gov (United States)

    Yeakub Ali, Mohammad; Banu, Asfana; Abu Bakar, Mazilah

    2018-01-01

    In obtaining the best quality of engineering components, the quality of machined parts surface plays an important role. It improves the fatigue strength, wear resistance, and corrosion of workpiece. This paper investigates the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness of stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The parameters selected are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical model was developed for the estimation of surface roughness. The analysis revealed that off time has a major influence on surface roughness. The optimum machining parameters for minimum surface roughness were found to be at a 10 V open voltage, 2.84 μs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

  2. Effect of different machining processes on the tool surface integrity and fatigue life

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chuan Liang [College of Mechanical and Electrical Engineering, Nanchang University, Nanchang (China); Zhang, Xianglin [School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan (China)

    2016-08-15

    Ultra-precision grinding, wire-cut electro discharge machining and lapping are often used to machine the tools in fine blanking industry. And the surface integrity from these machining processes causes great concerns in the research field. To study the effect of processing surface integrity on the fine blanking tool life, the surface integrity of different tool materials under different processing conditions and its influence on fatigue life were thoroughly analyzed in the present study. The result shows that the surface integrity of different materials was quite different on the same processing condition. For the same tool material, the surface integrity on varying processing conditions was quite different too and deeply influenced the fatigue life.

  3. Precise on-machine extraction of the surface normal vector using an eddy current sensor array

    International Nuclear Information System (INIS)

    Wang, Yongqing; Lian, Meng; Liu, Haibo; Ying, Yangwei; Sheng, Xianjun

    2016-01-01

    To satisfy the requirements of on-machine measurement of the surface normal during complex surface manufacturing, a highly robust normal vector extraction method using an Eddy current (EC) displacement sensor array is developed, the output of which is almost unaffected by surface brightness, machining coolant and environmental noise. A precise normal vector extraction model based on a triangular-distributed EC sensor array is first established. Calibration of the effects of object surface inclination and coupling interference on measurement results, and the relative position of EC sensors, is involved. A novel apparatus employing three EC sensors and a force transducer was designed, which can be easily integrated into the computer numerical control (CNC) machine tool spindle and/or robot terminal execution. Finally, to test the validity and practicability of the proposed method, typical experiments were conducted with specified testing pieces using the developed approach and system, such as an inclined plane and cylindrical and spherical surfaces. (paper)

  4. Precise on-machine extraction of the surface normal vector using an eddy current sensor array

    Science.gov (United States)

    Wang, Yongqing; Lian, Meng; Liu, Haibo; Ying, Yangwei; Sheng, Xianjun

    2016-11-01

    To satisfy the requirements of on-machine measurement of the surface normal during complex surface manufacturing, a highly robust normal vector extraction method using an Eddy current (EC) displacement sensor array is developed, the output of which is almost unaffected by surface brightness, machining coolant and environmental noise. A precise normal vector extraction model based on a triangular-distributed EC sensor array is first established. Calibration of the effects of object surface inclination and coupling interference on measurement results, and the relative position of EC sensors, is involved. A novel apparatus employing three EC sensors and a force transducer was designed, which can be easily integrated into the computer numerical control (CNC) machine tool spindle and/or robot terminal execution. Finally, to test the validity and practicability of the proposed method, typical experiments were conducted with specified testing pieces using the developed approach and system, such as an inclined plane and cylindrical and spherical surfaces.

  5. Dry Machining Aeronautical Aluminum Alloy AA2024-T351: Analysis of Cutting Forces, Chip Segmentation and Built-Up Edge Formation

    Directory of Open Access Journals (Sweden)

    Badis Haddag

    2016-08-01

    Full Text Available In this paper, machining aeronautical aluminum alloy AA2024-T351 in dry conditions was investigated. Cutting forces, chip segmentation, and built-up edge formation were analyzed. Machining tests revealed that the chip formation process depends on cutting conditions and tool geometry. So continuous and segmented chips are generated. Under some cutting conditions, built-up edge formation occurs. A predictive machining theory, based on a finite elements method (FEM, was applied to reproduce and explain these phenomena. Thermomechanical behaviors of the work material and the tool-work material interface were considered. Results of the proposed modelling were compared to experimental data for a wide range of cutting speed. It was shown that the feed force is well reproduced by the ALE-FE (arbitrary lagrangian-eulerian finite element formulation and highly underestimated by the lagrangian finite element (LAG-FE one. While, the periodic localized shear band, leading to a chip segmentation, is well reproduced with the Lagrangian FE formulation. It was found that the chip segmentation can be correlated to the cutting force evolution using the defined chip segmentation intensity parameter. For the built-up edge (BUE phenomenon, it was shown that it depends on the contact/friction at the tool-chip interface, and this is possible to simulate by making the friction coefficient time-dependent.

  6. Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Fang Liang

    2014-08-01

    Full Text Available Nature shows many examples of surfaces with extraordinary wettability, which can often be associated with particular air-trapping surface patterns. Here, robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE. The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters, both of which make it a strong candidate for industrial applications.

  7. Robust non-wetting PTFE surfaces by femtosecond laser machining.

    Science.gov (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie

    2014-08-08

    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  8. Fabrication and icing property of superhydrophilic and superhydrophobic aluminum surfaces derived from anodizing aluminum foil in a sodium chloride aqueous solution

    Science.gov (United States)

    Song, Meirong; Liu, Yuru; Cui, Shumin; Liu, Long; Yang, Min

    2013-10-01

    An aluminum foil with a rough surface was first prepared by anodic treatment in a neutral aqueous solution with the help of pitting corrosion of chlorides. First, the hydrophobic Al surface (contact angle around 79°) became superhydrophilic (contact angle smaller than 5°) after the anodizing process. Secondly, the superhydrophilic Al surface became superhydrophobic (contact angle larger than 150°) after being modified by oleic acid. Finally, the icing property of superhydrophilic, untreated, and superhydrophobic Al foils were investigated in a refrigerated cabinet at -12 °C. The mean total times to freeze a water droplet (6 μL) on the three foils were 17 s, 158 s and 1604 s, respectively. Thus, the superhydrophilic surface accelerates the icing process, while the superhydrophobic surface delays the process. The main reason for this transition might mainly result from the difference of the contact area of the water droplet with Al substrate: the increase in contact area with Al substrate will accelerate the heat conduct process, as well as the icing process; the decrease in contact area with Al substrate will delay the heat conduct process, as well as the icing process. Compared to the untreated Al foil, the contact area of the water droplet with the Al substrate was higher on superhydrophilic surface and smaller on the superhydrophobic surface, which led to the difference of the heat transfer time as well as the icing time.

  9. Plastic strain and grain size effects in the surface roughening of a model aluminum alloy

    Science.gov (United States)

    Moore, Eric Joseph

    To address issues surrounding improved automotive fuel economy, an experiment was designed to study the effect of uniaxial plastic tensile deformation on surface roughness and on slip and grain rotation. Electron backscatter diffraction (EBSD) and scanning laser confocal microscopy (SLCM) were used to track grain size, crystallographic texture, and surface topography as a function of incremental true strain for a coarse-grained binary alloy that is a model for AA5xxx series aluminum alloys. One-millimeter thick sheets were heat treated at 425°C to remove previous rolling texture and to grow grains to sizes in the range ˜10-8000 mum. At five different strain levels, 13 sample regions, containing 43 grains, were identified in both EBSD and SLCM micrographs, and crystallographic texture and surface roughness were measured. After heat treatment, a strong cube texture matrix emerged, with bands of generally non-cube grains embedded parallel to the rolling direction (RD). To characterize roughness, height profiles from SLCM micrographs were extracted and a filtered Fourier transform approach was used to separate the profiles into intergranular (long wavelength) and intragranular (short wavelength) signatures. The commonly-used rms roughness parameter (Rq) characterized intragranular results. Two important parameters assess intergranular results in two grain size regimes: surface tilt angle (Deltatheta) and surface height discontinuity (DeltazH) between neighboring grains at a boundary. In general, the magnitude of Rq and Deltatheta increase monotonically with strain and indicate that intergranular roughness is the major contributor to overall surface roughness for true strains up to epsilon = 0.12. Surface height discontinuity DeltazH is defined due to exceptions in surface tilt angle analyses. The range of observed Deltatheta= 1-10° are consistent with the observed 3-12° rotation of individual grains as measured with EBSD. For some grain boundaries with Deltatheta

  10. Effect of processing parameters of rotary ultrasonic machining on surface integrity of potassium dihydrogen phosphate crystals

    Directory of Open Access Journals (Sweden)

    Jianfu Zhang

    2015-09-01

    Full Text Available Potassium dihydrogen phosphate is an important optical crystal. However, high-precision processing of large potassium dihydrogen phosphate crystal workpieces is difficult. In this article, surface roughness and subsurface damage characteristics of a (001 potassium dihydrogen phosphate crystal surface produced by traditional and rotary ultrasonic machining are studied. The influence of process parameters, including spindle speed, feed speed, type and size of sintered diamond wheel, ultrasonic power, and selection of cutting fluid on potassium dihydrogen phosphate crystal surface integrity, was analyzed. The surface integrity, especially the subsurface damage depth, was affected significantly by the ultrasonic power. Metal-sintered diamond tools with high granularity were most suitable for machining potassium dihydrogen phosphate crystal. Cutting fluid played a key role in potassium dihydrogen phosphate crystal machining. A more precise surface can be obtained in machining with a higher spindle speed, lower feed speed, and using kerosene as cutting fluid. Based on the provided optimized process parameters for machining potassium dihydrogen phosphate crystal, a processed surface quality with Ra value of 33 nm and subsurface damage depth value of 6.38 μm was achieved.

  11. Assessment of surface acidity in mesoporous materials containing aluminum and titanium

    Science.gov (United States)

    Araújo, Rinaldo S.; Maia, Débora A. S.; Azevedo, Diana C. S.; Cavalcante, Célio L., Jr.; Rodríguez-Castellón, E.; Jimenez-Lopez, A.

    2009-04-01

    The surface acidity of mesoporous molecular sieves of aluminum and titanium was evaluated using four different techniques: n-butylamine volumetry, cyclohexylamine thermodesorption, temperature-programmed desorption of ammonia and adsorption of pyridine. The nature, strength and concentration of the acid sites were determined and correlated to the results of a probe reaction of anthracene oxidation to 9,10-anthraquinone (in liquid phase). In general, the surface acidity was highly influenced by the nature, location and coordination of the metal species (Al and Ti) in the mesoporous samples. Moderate to strong Brönsted acid sites were identified for the Al-MCM-41 sample in a large temperature range. For mesoporous materials containing Ti, the acidity was represented by a combination of weak to moderate Brönsted and Lewis acid sites. The Ti-HMS sample exhibits a higher acidity of moderate strength together with a well-balanced concentration of Brönsted and Lewis acid sites, which enhanced both conversion and selectivity in the oxidation reaction of anthracene.

  12. Trim cut machining and surface integrity analysis of Nimonic 80A alloy using wire cut EDM

    Directory of Open Access Journals (Sweden)

    Amitesh Goswami

    2017-02-01

    Full Text Available This present work deals with the features of trim cut wire EDM machining of Nimonic 80A in terms of machining parameters, to predict material removal rate (MRR, surface roughness (Ra, wire wear ratio (WWR and microstructure analysis. Trim cut is performed after rough cut to remove the rough layer deposited after machining due to melting and re-solidification of the eroded metal from workpiece as well as from wire electrode. Taguchi’s design of experiments methodology has been used for planning and designing the experiments. The relative significance of various factors has also been evaluated and analyzed using ANOVA. The results clearly indicate trim cut potential for high surface finish compared to rough cut machining.

  13. Non-Destructive Analysis of Basic Surface Characteristics of Titanium Dental Implants Made by Miniature Machining

    Science.gov (United States)

    Babík, Ondrej; Czán, Andrej; Holubják, Jozef; Kameník, Roman; Pilc, Jozef

    2016-12-01

    One of the most best-known characteristic and important requirement of dental implant is made of biomaterials ability to create correct interaction between implant and human body. The most implemented material in manufacturing of dental implants is titanium of different grades of pureness. Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on the successful osseointegration. Among other characteristics of titanium that predetermine ideal biomaterial, it shows a high mechanical strength making precise machining miniature Increasingly difficult. The article is focused on evaluation of the resulting quality, integrity and characteristics of dental implants surface after machining.

  14. Wire Electrical Discharge Machining of a Hybrid Composite: Evaluation of Kerf Width and Surface Roughness

    Directory of Open Access Journals (Sweden)

    Abdil KUŞ

    2016-06-01

    Full Text Available In this study, the machinability characteristics of Al/B4C-Gr hybrid composite were investigated using wire electrical discharge machining (WEDM. In the experiments, the machining parameters of wire speed, pulse-on time and pulse-off time were varied in order to explaiın their effects on machining performance, including the width of slit (kerf and surface roughness values (Rz and Rt. According to the Taguchi quality design concept, a L18 (21×32 orthogonal array was used to determine the S/N ratio, and analysis of variance (ANOVA and the F-test were used to indicate the significant machining parameters affecting the machining performance. From the ANOVA and F-test results, the significant factors were determined for each of the machining performance criteria of kerf, Rz and Rt. The variations of kerf, Rz and Rt with the machining parameters were statistically modeled via the regression analysis method. The optimum levels of the control factors for kerf, Rz and Rt were specified as A1B1C1, A1B1C2 and A1B1C2, respectively. The correlation coefficients of the predictive equations developed for kerf, Rz and Rt were calculated as 0.98, 0.828 and 0.855, respectively.

  15. Ultra-precision machining induced phase decomposition at surface of Zn-Al based alloy

    International Nuclear Information System (INIS)

    To, S.; Zhu, Y.H.; Lee, W.B.

    2006-01-01

    The microstructural changes and phase transformation of an ultra-precision machined Zn-Al based alloy were examined using X-ray diffraction and back-scattered electron microscopy techniques. Decomposition of the Zn-rich η phase and the related changes in crystal orientation was detected at the surface of the ultra-precision machined alloy specimen. The effects of the machining parameters, such as cutting speed and depth of cut, on the phase decomposition were discussed in comparison with the tensile and rolling induced microstrucutural changes and phase decomposition

  16. Optical micro-metrology of structured surfaces micro-machined by jet-ECM

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Tosello, Guido; Islam, Aminul

    2015-01-01

    A procedure for statistical analysis and uncertainty evaluation is presented with regards to measurements of step height and surface texture. Measurements have been performed with a focus-variation microscope over jet electrochemical micro-machined surfaces. Traceability has been achieved using a...

  17. Study of the Effect of Material Machinability on Quality of Surface Created by Abrasive Water Jet

    Czech Academy of Sciences Publication Activity Database

    Klichová, Dagmar; Klich, Jiří

    2016-01-01

    Roč. 149, č. 149 (2016), s. 177-182 E-ISSN 1877-7058. [International Conference on Manufacturing Engineering and Materials, ICMEM 2016. Nový Smokovec, 06.06.2016-10.06.2016] R&D Projects: GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : machinability * surface roughness * abrasive water jet * study of quality * aluminium alloy * optical profilometer Subject RIV: JQ - Machines ; Tools http://www.sciencedirect.com/science/article/pii/S1877705816311614

  18. Effect of machining parameters on surface textures in EDM of Fe-Mn-Al alloy

    International Nuclear Information System (INIS)

    Guu, Y.H.; Hou, Max Ti-Kuang

    2007-01-01

    In this work, the surface characteristics caused by EDM were analyzed by means of the atomic force microscopy (AFM) technique. An empirical model of Fe-Mn-Al alloy was proposed based on the experimental data. A qualitative energy dispersive spectroscopic analyzer was used to measure the chemical composition of the specimen. Surface hardness was determined with a microhardness tester. Experimental results indicate that the EDM process causes a ridged surface and induces machining damage in the surface layer, and increases the surface roughness. The depth of micro-cracks, micro-voids and machined damage increase with an increase in the amount of pulsed current and pulse-on duration. The effect of the magnitude of the pulse-on duration on the surface texture of the specimen is more significant than the pulsed current. Furthermore, the AFM method reveals the 3D surface textures of the EDM specimen with a nanometer scale

  19. Whole surface image reconstruction for machine vision inspection of fruit

    Science.gov (United States)

    Reese, D. Y.; Lefcourt, A. M.; Kim, M. S.; Lo, Y. M.

    2007-09-01

    Automated imaging systems offer the potential to inspect the quality and safety of fruits and vegetables consumed by the public. Current automated inspection systems allow fruit such as apples to be sorted for quality issues including color and size by looking at a portion of the surface of each fruit. However, to inspect for defects and contamination, the whole surface of each fruit must be imaged. The goal of this project was to develop an effective and economical method for whole surface imaging of apples using mirrors and a single camera. Challenges include mapping the concave stem and calyx regions. To allow the entire surface of an apple to be imaged, apples were suspended or rolled above the mirrors using two parallel music wires. A camera above the apples captured 90 images per sec (640 by 480 pixels). Single or multiple flat or concave mirrors were mounted around the apple in various configurations to maximize surface imaging. Data suggest that the use of two flat mirrors provides inadequate coverage of a fruit but using two parabolic concave mirrors allows the entire surface to be mapped. Parabolic concave mirrors magnify images, which results in greater pixel resolution and reduced distortion. This result suggests that a single camera with two parabolic concave mirrors can be a cost-effective method for whole surface imaging.

  20. Effect of surface machining on corrosion behavior of SA182-304 in simulated

    International Nuclear Information System (INIS)

    Zhang Zhiming; Wang Jianqiu; Han Enhou; Ke Wei

    2015-01-01

    Different machining processes of mechanical parts can cause surface damage layers with different levels. The surface deformed layer can affect the corrosion behavior and service life of these mechanical parts a lot during the following service process. As a result, it is a key issue for the fabrication of the mechanical parts with long life that the selection of proper machining parameters and the removal of surface damage. The purpose of this study is to study the influence of different turning parameters on the corrosion behavior of nuclear grade SA182-304 stainless steel widely used in the advanced pressured water reactors (PWRs). 6 kinds of samples with different surface state are prepared by a lathe with different machining parameters, such as the feed, cutting speed and back engagement of the cutting edge. The high temperature and high pressure immersion test of these samples in the simulated PWR primary watershows that machining processes can affect the microstructure and chemical composition of the formed surface oxide scales a lot. According to the experimental results, the proper machining parameters for the studied SA182-304 are suggested. (authors)

  1. Functional aluminum alloys for ultra high vacuum use

    International Nuclear Information System (INIS)

    Kato, Yutaka; Tsukamoto, Kenji; Isoyama, Eizo

    1985-01-01

    Ultra high vacuum systems made of aluminum alloys are actively developed. The reasons for using aluminum alloys are low residual radioactivity, light weight, good machinability, good thermal conductivity, non-magnetism. The important function required for ultra high vacuum materials is low outgassing rate, but surface gas on ordinary aluminum is much. Then the research on aluminum surface structure with low outgassing rate has been made and the special extrusion method, that is, extrusion method with the conditions of preventing air from entering inside of pipe and of taking in mixture gas of Ar + O 2 , was developed. 6063 alloy obtained by special extrusion method showed low outgassing rate (2 x 10 -13 Torr. 1/s. cm 2 ) by only 150 deg C, 24 h baking. For the future it will be important to develop aluminum alloys with low dynamic outgassing rate as well as low static outgassing rate. (author)

  2. Fibroblast adhesion and activation onto micro-machined titanium surfaces.

    Science.gov (United States)

    Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

    2013-07-01

    Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (fibrotic response. © 2012 John Wiley & Sons A/S.

  3. Empirical model for estimating the surface roughness of machined ...

    African Journals Online (AJOL)

    Michael Horsfall

    one of the most critical quality measure in mechanical products. In the ... Keywords: cutting speed, centre lathe, empirical model, surface roughness, Mean absolute percentage deviation ... The factors considered were work piece properties.

  4. Effect of Fe- and Si-Enriched Secondary Precipitates and Surface Roughness on Pore Formation on Aluminum Plate Surfaces During Anodizing

    Science.gov (United States)

    Zhu, Yuanzhi; Wang, Shizhi; Yang, Qingda; Zhou, Feng

    2014-09-01

    Two twin roll casts (TRCs) and one hot rolled (HR) AA 1235 aluminum alloy plates with different microstructures are prepared. The plates were electrolyzed in a 1.2 wt% HCl solution with a voltage of 21 V and a current of 1.9 mA. The shape, size, and number of pores formed on the surfaces of these plates were analyzed and correlated with the microstructures of the plates. It is found that pores are easier to form on the alloy plates containing subgrains with a lower dislocation density inside the subgrains, rather than along the grain boundaries. Furthermore, Fe- and Si-enriched particles in the AA1235 aluminum alloys lead to the formation of pores on the surface during electrolyzing; the average precipitate sizes of 4, 3.5, and 2 μm in Alloy 1#, Alloy 2# and Alloy 3# result in the average pore sizes of 3.78, 2.76, and 1.9 μm on the surfaces of the three alloys, respectively; The G.P zone in the alloy also facilitates the surface pore formation. High-surface roughness enhances the possibility of entrapping more lubricants into the plate surface, which eventually blocks the formation of the pores on the surface of the aluminum plates in the following electrolyzing process.

  5. The survey of the surface doses of the dental x-ray machines

    International Nuclear Information System (INIS)

    Lee, Jae Seo; Kang, Byung Cheol; Yoon, Suk Ja

    2005-01-01

    The purpose of this study was to investigate variability of doses with same exposure parameters and evaluate radiographic density according to the variability of doses. Twenty-eight MAX-GLS (Shinhung Co, Seoul, Korea), twenty-one D-60-S (DongSeo Med, Seoul, Korea), and eleven REX-601 (Yoshida Dental MFG, Tokyo, Japan) dental x-ray machines were selected for this study. Surface doses were measured under selected combinations of tube voltage, tube current, exposure time, and constant distance 42 cm from the focal spot to the surface of the Multi-O-meter (Unfors Instrument, Billdal, Sweden). Radiographic densities were measured on the films at maximum, minimum and mean surface doses of each brand of x-ray units. With MAX-GLS, the maximum surface doses were thirteen to fourteen times as much as the minimum surfaces doses. With D-60-S, the maximum surface doses were three to eight times as much as the minimum surface doses. With REX-601, the maximum surface doses were six to ten times as much as the minimum surface doses. The differences in radiographic densities among maximum, mean, and minimum doses were significant (p<0.01). The surface exposure doses of each x-ray machine at the same exposure parameters were different within the same manufacturer's machines.

  6. Automatic inspection of textured surfaces by support vector machines

    Science.gov (United States)

    Jahanbin, Sina; Bovik, Alan C.; Pérez, Eduardo; Nair, Dinesh

    2009-08-01

    Automatic inspection of manufactured products with natural looking textures is a challenging task. Products such as tiles, textile, leather, and lumber project image textures that cannot be modeled as periodic or otherwise regular; therefore, a stochastic modeling of local intensity distribution is required. An inspection system to replace human inspectors should be flexible in detecting flaws such as scratches, cracks, and stains occurring in various shapes and sizes that have never been seen before. A computer vision algorithm is proposed in this paper that extracts local statistical features from grey-level texture images decomposed with wavelet frames into subbands of various orientations and scales. The local features extracted are second order statistics derived from grey-level co-occurrence matrices. Subsequently, a support vector machine (SVM) classifier is trained to learn a general description of normal texture from defect-free samples. This algorithm is implemented in LabVIEW and is capable of processing natural texture images in real-time.

  7. Machine learning and pattern recognition from surface molecular architectures.

    Science.gov (United States)

    Maksov, Artem; Ziatdinov, Maxim; Fujii, Shintaro; Sumpter, Bobby; Kalinin, Sergei

    The ability to utilize molecular assemblies as data storage devices requires capability to identify individual molecular states on a scale of thousands of molecules. We present a novel method of applying machine learning techniques for extraction of positional and rotational information from ultra-high vacuum scanning tunneling microscopy (STM) images and apply it to self-assembled monolayer of π-bowl sumanene molecules on gold. From density functional theory (DFT) simulations, we assume existence of distinct polar and multiple azimuthal rotational states. We use DFT-generated templates in conjunction with Markov Chain Monte Carlo (MCMC) sampler and noise modeling to create synthetic images representative of our model. We extract positional information of each molecule and use nearest neighbor criteria to construct a graph input to Markov Random Field (MRF) model to identify polar rotational states. We train a convolutional Neural Network (cNN) on a synthetic dataset and combine it with MRF model to classify molecules based on their azimuthal rotational state. We demonstrate effectiveness of such approach compared to other methods. Finally, we apply our approach to experimental images and achieve complete rotational class information extraction. This research was sponsored by the Division of Materials Sciences and Engineering, Office of Science, Basic Energy Sciences, US DOE.

  8. Metrological Aspects of Surface Topographies Produced by Different Machining Operations Regarding Their Potential Functionality

    Directory of Open Access Journals (Sweden)

    Żak Krzysztof

    2017-06-01

    Full Text Available This paper presents a comprehensive methodology for measuring and characterizing the surface topographies on machined steel parts produced by precision machining operations. The performed case studies concern a wide spectrum of topographic features of surfaces with different geometrical structures but the same values of the arithmetic mean height Sa. The tested machining operations included hard turning operations performed with CBN tools, grinding operations with Al2O3 ceramic and CBN wheels and superfinish using ceramic stones. As a result, several characteristic surface textures with the Sa roughness parameter value of about 0.2 μm were thoroughly characterized and compared regarding their potential functional capabilities. Apart from the standard 2D and 3D roughness parameters, the fractal, motif and frequency parameters were taken in the consideration.

  9. Numerical analysis of special-shaped surface in abrasive flow machining

    Science.gov (United States)

    Li, Junye; Zhou, Zengwei; Wu, Guiling; Lu, Hui; Sun, Zhihuai

    2018-03-01

    Solid-liquid two-phase abrasive flow machining is a method to effectively polish the surface of Special-shaped surface parts. Based on the processing characteristics of the abrasive flow machining. The standard model and the pressure-coupled SIMPLEC algorithm are used. The shear force and velocity of the near-wall surface of the runner of the solid-liquid two-phase abrasive machining with different inlet pressure are analyzed. The numerical simulation results show that the inlet pressure has little effect on the velocity, and the shear force has a linear relationship with the inlet pressure. To obtain a better polishing effect, the outlet pressure can be appropriately increased.

  10. Prediction of residual stress distributions due to surface machining and welding and crack growth simulation under residual stress distribution

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Katsuyama, JInya; Onizawa, Kunio; Hashimoto, Tadafumi; Mikami, Yoshiki; Mochizuki, Masahito

    2011-01-01

    Research highlights: → Residual stress distributions due to welding and machining are evaluated by XRD and FEM. → Residual stress due to machining shows higher tensile stress than welding near the surface. → Crack growth analysis is performed using calculated residual stress. → Crack growth result is affected machining rather than welding. → Machining is an important factor for crack growth. - Abstract: In nuclear power plants, stress corrosion cracking (SCC) has been observed near the weld zone of the core shroud and primary loop recirculation (PLR) pipes made of low-carbon austenitic stainless steel Type 316L. The joining process of pipes usually includes surface machining and welding. Both processes induce residual stresses, and residual stresses are thus important factors in the occurrence and propagation of SCC. In this study, the finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining. The thermoelastic-plastic analysis was performed for the welding simulation, and the thermo-mechanical coupled analysis based on the Johnson-Cook material model was performed for the surface machining simulation. In addition, a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stress distributions that are generated by welding and surface machining. The surface machining analysis showed that tensile residual stress due to surface machining only exists approximately 0.2 mm from the machined surface, and the surface residual stress increases with cutting speed. The crack growth analysis showed that the crack depth is affected by both surface machining and welding, and the crack length is more affected by surface machining than by welding.

  11. 3D topography for environmentally friendly machined surfaces

    International Nuclear Information System (INIS)

    Dudas, I; Varga, G

    2005-01-01

    Nowadays more and more scientific paper deals with drilling. In recent years there have been limited changes to the drill design but considerable improvements have been made in the selection of drill materials, drill coatings, flute design and the cutting fluid guiding methods. All of these improvements have been introduced to improve the surface finish of the drilled hole, reduce the energy during drilling process and to reduce ecological damage to the cutting fluids, which carry away heat and debris from the cutting zone. The paper briefly describes the development of surface characterization to its current 3D capability. It shows how selected parameters can assist with drill process analysis and how this can be supported through the introduction of the planned new ISO International Standard for 3D surface characterization. The paper is supported by a sample-drilling test to demonstrate the power of the proposed analysis

  12. Laser machining micro-structures on diamond surface with a sub-nanosecond pulsed laser

    Science.gov (United States)

    Wu, Mingtao; Guo, Bing; Zhao, Qingliang

    2018-02-01

    Micro-structure surface on diamond material is widely used in a series of industrial and scientific applications, such as micro-electromechanical systems (MEMS), nanoelectromechanical systems (NEMS), microelectronics, textured or micro-structured diamond machining tools. The efficient machining of micro-structure on diamond surface is urgently demanded in engineering. In this paper, laser machining square micro-structure on diamond surface was studied with a sub-nanosecond pulsed laser. The influences of laser machining parameters, including the laser power, scanning speed, defocusing quantity and scanning pitch, were researched in view of the ablation depth, material removal rate and machined surface topography. Both the ablation depth and material removal rate increased with average laser power. A reduction of the growth rate of the two parameters was induced by the absorption of the laser plasma plume at high laser power. The ablation depth non-linearly decreased with the increasing of the scanning speed while the material removal rate showed an opposite tendency. The increasing of the defocusing quantity induced complex variation of the ablation depth and the material removal rate. The maximum ablation depth and material removal rate were achieved at a defocusing position. The ablation depth and material removal rate oppositely varied about the scanning pitch. A high overlap ratio was meaningful for achieving a smooth micro-structure surface topography. Laser machining with a large defocusing quantity, high laser power and small scanning pitch was helpful for acquiring the desired micro-structure which had a large depth and smooth micro-structure surface topography.

  13. Surface Complexation Modeling of Fluoride Adsorption by Soil and the Role of Dissolved Aluminum on Adsorption

    Science.gov (United States)

    Padhi, S.; Tokunaga, T.

    2017-12-01

    Adsorption of fluoride (F) on soil can control the mobility of F and subsequent contamination of groundwater. Hence, accurate evaluation of adsorption equilibrium is a prerequisite for understanding transport and fate of F in the subsurface. While there have been studies for the adsorption behavior of F with respect to single mineral constituents based on surface complexation models (SCM), F adsorption to natural soil in the presence of complexing agents needs much investigation. We evaluated the adsorption processes of F on a natural granitic soil from Tsukuba, Japan, as a function of initial F concentration, ionic strength, and initial pH. A SCM was developed to model F adsorption behavior. Four possible surface complexation reactions were postulated with and without including dissolved aluminum (Al) and Al-F complex sorption. Decrease in F adsorption with the increase in initial pH was observed in between the initial pH range of 4 to 9, and a decrease in the rate of the reduction of adsorbed F with respect to the increase in the initial pH was observed in the initial pH range of 5 to 7. Ionic strength variation in the range of 0 to 100mM had insignificant effect on F removal. Changes in solution pH were observed by comparing the solution before and after F adsorption experiments. At acidic pH, the solution pH increased, whereas at alkaline pH, the solution pH decreased after equilibrium. The SCM including dissolved Al and the adsorption of Al-F complex can simulate the experimental results quite successfully. Also, including dissolved Al and the adsorption of Al-F complex to the model explained the change in solution pH after F adsorption.

  14. An experimental result of surface roughness machining performance in deep hole drilling

    Directory of Open Access Journals (Sweden)

    Mohamad Azizah

    2016-01-01

    Full Text Available This study presents an experimental result of a deep hole drilling process for Steel material at different machining parameters which are feed rate (f, spindle speed (s, the depth of the hole (d and MQL, number of drops (m on surface roughness, Ra. The experiment was designed using two level full factorial design of experiment (DoE with centre points to collect surface roughness, Ra values. The signal to noise (S/N ratio analysis was used to discover the optimum level for each machining parameters in the experiment.

  15. Effect of machining on the deformability of steel in surface-active medium at lower temperatures

    International Nuclear Information System (INIS)

    Gusti, E.Ya.; Babej, Yu.I.

    1977-01-01

    The effect of some machining methods of carbon steel, chromium steel, and chromium nickel steel, and that of low temperatures on the principle characteristics of formability during impact bending in air and a surface-active environment have been studied. The temperature decrease from the ambient to -80 deg is shown to reduce steel formability as evaluated by deflection (f) and to increase the forming force. The variation of these characteristics with lowering temperature, however, is greatly affected by machining process conditions. The FRHT (Friction-Hardening Treatment) on the white layer assures minimum ductility losses, and increases steel strength at low temperatures both in air and in the surface-active environment

  16. Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

    Directory of Open Access Journals (Sweden)

    Todor Ivanov

    2011-02-01

    Full Text Available Within the project Functional Surfaces via Micro- and Nanoscaled Structures?which is part of the Cluster of Excellence 揑ntegrative Production Technology?established and financed by the German Research Foundation (DFG, an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1 μm on near-net-shape-casting parts has been developed. The common way to realize functional microstructures on metallic surfaces is to use laser ablation, electro discharge machining or micro milling. The handicap of these processes is their limited productivity. The approach of this project to raise the efficiency is to use the investment casting process to replicate microstructured surfaces by moulding from a laser-microstructured grand master pattern. The main research objective deals with the investigation of the single process steps of the investment casting process with regard to the moulding accuracy. Actual results concerning making of the wax pattern, suitability of ceramic mould and core materials for casting of an AlSi7Mg0.3 alloy as well as the knock-out behavior of the shells are presented. By using of the example of an intake manifold of a gasoline race car engine, a technical shark skin surface has been realized to reduce the drag of the intake air. The intake manifold consists of an air-restrictor with a defined inner diameter which is microstructured with technical shark skin riblets. For this reason the inner diameter cannot be drilled after casting and demands a very high accuracy of the casting part. A technology for the fabrication and demoulding of accurate microstructured castings are shown. Shrinkage factors of different moulding steps of the macroscopic casting part as well as the microscopic riblet structure have been examined as well.

  17. Comparative Evaluation of Aluminum Sulfate and Ferric Sulfate-Induced Coagulations as Pretreatment of Microfiltration for Treatment of Surface Water

    Directory of Open Access Journals (Sweden)

    Yali Song

    2015-06-01

    Full Text Available Two coagulants, aluminum sulfate and ferric chloride, were tested to reduce natural organic matter (NOM as a pretreatment prior to polyvinylidene fluoride (PVDF microfiltration (MF membranes for potable water treatment. The results showed that the two coagulants exhibited different treatment performance in NOM removal. Molecular weight (MW distributions of NOM in the tested surface raw water were concentrated at 3–5 kDa and approximately 0.2 kDa. Regardless of the coagulant species and dosages, the removal of 0.2 kDa NOM molecules was limited. In contrast, NOM at 3–5 kDa were readily removed with increasing coagulant dosages. In particular, aluminum sulfate favorably removed NOM near 5 kDa, whereas ferric chloride tended to reduce 3 kDa organic substances. Although aluminum sulfate and ferric chloride could improve the flux of the ensuing MF treatment, the optimal coagulant dosages to achieve effective pretreatment were different: 2–30 mg/L for aluminum sulfate and >15 mg/L for ferric chloride. The scanning electron microscope (SEM image of the membrane-filtered coagulated raw water showed that coagulation efficiency dramatically affected membrane flux and that good coagulation properties can reduce membrane fouling.

  18. Processing, structure, property and performance relationships for the thermal spray of the internal surface of aluminum cylinders

    Science.gov (United States)

    Cook, David James

    The increased need for automotive weight reduction has necessitated the use of aluminum for engine blocks. Conventional aluminum alloys cannot survive the constant wear from a piston ring reciprocating on the surface. However, a wear resistant thermal spray coating can be applied on the internal surface of the cylinder bore, which has significant advantages over other available options. Thermal spray is a well-established process for depositing molten, semi-molten, or solid particles onto a substrate to form a protective coating. For this application, the two main challenges were obtaining good wear resistance, and achieving good adhesion. To design a system capable of producing a well-adhered, wear resistant coating for this high volume application it is necessary to identify the overall processing, structure, properties, and performance relationships. The results will demonstrate that very important relationships exist among particle characteristics, substrate conditions, and the properties of the final coating. However, it is the scientific studies to understand some of the process physics in these relationships that allow recognition of the critical processing conditions that need to be controlled to ensure a consistent, reliable thermal spray coating. In this investigation, it will be shown that the critical microstructural aspect of the coating that produced the required tribological properties was the presence of wuestite (FeO). It was found that by using a low carbon steel material with compressed air atomizing gas, it was possible to create an Fe/FeO structure that exhibited excellent tribological properties. This study will also show that traditional thermal spray surface preparation techniques were not ideal for this application, therefore a novel alternative approach was developed. The application of a flux to the aluminum surface prior to thermal spray promotes excellent bond strengths to non-roughened aluminum. Analysis will show that this flux strips

  19. Effect of Ceramic Surface Treatments After Machine Grinding on the Biaxial Flexural Strength of Different CAD/CAM Dental Ceramics.

    Science.gov (United States)

    Bagheri, Hossein; Hooshmand, Tabassom; Aghajani, Farzaneh

    2015-09-01

    This study aimed to evaluate the effect of different ceramic surface treatments after machining grinding on the biaxial flexural strength (BFS) of machinable dental ceramics with different crystalline phases. Disk-shape specimens (10mm in diameter and 1.3mm in thickness) of machinable ceramic cores (two silica-based and one zirconia-based ceramics) were prepared. Each type of the ceramic surfaces was then randomly treated (n=15) with different treatments as follows: 1) machined finish as control, 2) machined finish and sandblasting with alumina, and 3) machined finish and hydrofluoric acid etching for the leucite and lithium disilicate-based ceramics, and for the zirconia; 1) machined finish and post-sintered as control, 2) machined finish, post-sintered, and sandblasting, and 3) machined finish, post-sintered, and Nd;YAG laser irradiation. The BFS were measured in a universal testing machine. Data based were analyzed by ANOVA and Tukey's multiple comparisons post-hoc test (α=0.05). The mean BFS of machined finish only surfaces for leucite ceramic was significantly higher than that of sandblasted (P=0.001) and acid etched surfaces (P=0.005). A significantly lower BFS was found after sandblasting for lithium disilicate compared with that of other groups (Pceramics was affected by the type of ceramic material and surface treatment method. Sandblasting with alumina was detrimental to the strength of only silica-based ceramics. Nd:YAG laser irradiation may lead to substantial strength degradation of zirconia.

  20. High-pressure coolant effect on the surface integrity of machining titanium alloy Ti-6Al-4V: a review

    Science.gov (United States)

    Liu, Wentao; Liu, Zhanqiang

    2018-03-01

    Machinability improvement of titanium alloy Ti-6Al-4V is a challenging work in academic and industrial applications owing to its low thermal conductivity, low elasticity modulus and high chemical affinity at high temperatures. Surface integrity of titanium alloys Ti-6Al-4V is prominent in estimating the quality of machined components. The surface topography (surface defects and surface roughness) and the residual stress induced by machining Ti-6Al-4V occupy pivotal roles for the sustainability of Ti-6Al-4V components. High-pressure coolant (HPC) is a potential choice in meeting the requirements for the manufacture and application of Ti-6Al-4V. This paper reviews the progress towards the improvements of Ti-6Al4V surface integrity under HPC. Various researches of surface integrity characteristics have been reported. In particularly, surface roughness, surface defects, residual stress as well as work hardening are investigated in order to evaluate the machined surface qualities. Several coolant parameters (including coolant type, coolant pressure and the injection position) deserve investigating to provide the guidance for a satisfied machined surface. The review also provides a clear roadmap for applications of HPC in machining Ti-6Al4V. Experimental studies and analysis are reviewed to better understand the surface integrity under HPC machining process. A distinct discussion has been presented regarding the limitations and highlights of the prospective for machining Ti-6Al4V under HPC.

  1. Effect of Built-Up Edge Formation during Stable State of Wear in AISI 304 Stainless Steel on Machining Performance and Surface Integrity of the Machined Part.

    Science.gov (United States)

    Ahmed, Yassmin Seid; Fox-Rabinovich, German; Paiva, Jose Mario; Wagg, Terry; Veldhuis, Stephen Clarence

    2017-10-25

    During machining of stainless steels at low cutting -speeds, workpiece material tends to adhere to the cutting tool at the tool-chip interface, forming built-up edge (BUE). BUE has a great importance in machining processes; it can significantly modify the phenomenon in the cutting zone, directly affecting the workpiece surface integrity, cutting tool forces, and chip formation. The American Iron and Steel Institute (AISI) 304 stainless steel has a high tendency to form an unstable BUE, leading to deterioration of the surface quality. Therefore, it is necessary to understand the nature of the surface integrity induced during machining operations. Although many reports have been published on the effect of tool wear during machining of AISI 304 stainless steel on surface integrity, studies on the influence of the BUE phenomenon in the stable state of wear have not been investigated so far. The main goal of the present work is to investigate the close link between the BUE formation, surface integrity and cutting forces in the stable sate of wear for uncoated cutting tool during the cutting tests of AISI 304 stainless steel. The cutting parameters were chosen to induce BUE formation during machining. X-ray diffraction (XRD) method was used for measuring superficial residual stresses of the machined surface through the stable state of wear in the cutting and feed directions. In addition, surface roughness of the machined surface was investigated using the Alicona microscope and Scanning Electron Microscopy (SEM) was used to reveal the surface distortions created during the cutting process, combined with chip undersurface analyses. The investigated BUE formation during the stable state of wear showed that the BUE can cause a significant improvement in the surface integrity and cutting forces. Moreover, it can be used to compensate for tool wear through changing the tool geometry, leading to the protection of the cutting tool from wear.

  2. Surface integrity and fatigue behaviour of electric discharged machined and milled austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, Mattias, E-mail: mattias.lundberg@liu.se; Saarimäki, Jonas; Moverare, Johan J.; Calmunger, Mattias

    2017-02-15

    Machining of austenitic stainless steels can result in different surface integrities and different machining process parameters will have a great impact on the component fatigue life. Understanding how machining processes affect the cyclic behaviour and microstructure are of outmost importance in order to improve existing and new life estimation models. Milling and electrical discharge machining (EDM) have been used to manufacture rectangular four-point bend fatigue test samples; subjected to high cycle fatigue. Before fatigue testing, surface integrity characterisation of the two surface conditions was conducted using scanning electron microscopy, surface roughness, residual stress profiles, and hardness profiles. Differences in cyclic behaviour were observed between the two surface conditions by the fatigue testing. The milled samples exhibited a fatigue limit. EDM samples did not show the same behaviour due to ratcheting. Recrystallized nano sized grains were identified at the severely plastically deformed surface of the milled samples. Large amounts of bent mechanical twins were observed ~ 5 μm below the surface. Grain shearing and subsequent grain rotation from milling bent the mechanical twins. EDM samples showed much less plastic deformation at the surface. Surface tensile residual stresses of ~ 500 MPa and ~ 200 MPa for the milled and EDM samples respectively were measured. - Highlights: •Milled samples exhibit fatigue behaviour, but not EDM samples. •Four-point bending is not suitable for materials exhibiting pronounced ratcheting. •LAGB density can be used to quantitatively measure plastic deformation. •Grain shearing and rotation result in bent mechanical twins. •Nano sized grains evolve due to the heat of the operation.

  3. Anisotropic wetting characteristics versus roughness on machined surfaces of hydrophilic and hydrophobic materials

    International Nuclear Information System (INIS)

    Liang, Yande; Shu, Liming; Natsu, Wataru; He, Fuben

    2015-01-01

    Graphical abstract: - Highlights: • The aim is to investigate the influence of roughness on anisotropic wetting on machined surfaces. • The relationship between roughness and anisotropic wetting is modeled by thermodynamical analysis. • The effect of roughness on anisotropic wetting on hydrophilic materials is stronger than that on hydrophobic materials. • The energy barrier existing in the direction perpendicular to the lay is one of the main reasons for the anisotropic wetting. • The contact angle in the parallel direction is larger than that in the perpendicular direction. - Abstract: Anisotropic wetting of machined surfaces is widely applied in industries which can be greatly affected by roughness and solid's chemical properties. However, there has not been much work on it. A free-energy thermodynamic model is presented by analyzing geometry morphology of machined surfaces (2-D model surfaces), which demonstrates the influence of roughness on anisotropic wetting. It can be concluded that the energy barrier is one of the main reasons for the anisotropic wetting existing in the direction perpendicular to the lay. In addition, experiments in investigating anisotropic wetting, which was characterized by the static contact angle and droplet's distortion, were performed on machined surfaces with different roughness on hydrophilic and hydrophobic materials. The droplet's anisotropy found on machined surfaces increased with mean slope of roughness profile Kr. It indicates that roughness on anisotropic wetting on hydrophilic materials has a stronger effect than that on hydrophobic materials. Furthermore, the contact angles predicted by the model are basically consistent with the experimentally ones

  4. The Effectiveness of Surface Coatings on Preventing Interfacial Reaction During Ultrasonic Welding of Aluminum to Magnesium

    Science.gov (United States)

    Panteli, Alexandria; Robson, Joseph D.; Chen, Ying-Chun; Prangnell, Philip B.

    2013-12-01

    High power ultrasonic spot welding (USW) is a solid-state joining process that is advantageous for welding difficult dissimilar material couples, like magnesium to aluminum. USW is also a useful technique for testing methods of controlling interfacial reaction in welding as the interface is not greatly displaced by the process. However, the high strain rate deformation in USW has been found to accelerate intermetallic compound (IMC) formation and a thick Al12Mg17 and Al3Mg2 reaction layer forms after relatively short welding times. In this work, we have investigated the potential of two approaches for reducing the IMC reaction rate in dissimilar Al-Mg ultrasonic welds, both involving coatings on the Mg sheet surface to (i) separate the join line from the weld interface, using a 100- μm-thick Al cold spray coating, and (ii) provide a diffusion barrier layer, using a thin manganese physical vapor deposition (PVD) coating. Both methods were found to reduce the level of reaction and increase the failure energy of the welds, but their effectiveness was limited due to issues with coating attachment and survivability during the welding cycle. The effect of the coatings on the joint's interface microstructure, and the fracture behavior have been investigated in detail. Kinetic modeling has been used to show that the benefit of the cold spray coating can be attributed to the reaction rate reverting to that expected under static conditions. This reduces the IMC growth rate by over 50 pct because at the weld line, the high strain rate dynamic deformation in USW normally enhances diffusion through the IMC layer. In comparison, the thin PVD barrier coating was found to rapidly break up early in USW and become dispersed throughout the deformation layer reducing its effectiveness.

  5. Surface topography characterization using an atomic force microscope mounted on a coordinate measuring machine

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Hansen, H.N; Kofod, N

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...

  6. Surface roughness optimization in machining of AZ31 magnesium alloy using ABC algorithm

    Directory of Open Access Journals (Sweden)

    Abhijith

    2018-01-01

    Full Text Available Magnesium alloys serve as excellent substitutes for materials traditionally used for engine block heads in automobiles and gear housings in aircraft industries. AZ31 is a magnesium alloy finds its applications in orthopedic implants and cardiovascular stents. Surface roughness is an important parameter in the present manufacturing sector. In this work optimization techniques namely firefly algorithm (FA, particle swarm optimization (PSO and artificial bee colony algorithm (ABC which are based on swarm intelligence techniques, have been implemented to optimize the machining parameters namely cutting speed, feed rate and depth of cut in order to achieve minimum surface roughness. The parameter Ra has been considered for evaluating the surface roughness. Comparing the performance of ABC algorithm with FA and PSO algorithm, which is a widely used optimization algorithm in machining studies, the results conclude that ABC produces better optimization when compared to FA and PSO for optimizing surface roughness of AZ 31.

  7. Simulation of dynamic processes when machining transition surfaces of stepped shafts

    Science.gov (United States)

    Maksarov, V. V.; Krasnyy, V. A.; Viushin, R. V.

    2018-03-01

    The paper addresses the characteristics of stepped surfaces of parts categorized as "solids of revolution". It is noted that in the conditions of transition modes during the switch to end surface machining, there is cutting with varied load intensity in the section of the cut layer, which leads to change in cutting force, onset of vibrations, an increase in surface layer roughness, a decrease of size precision, and increased wear of a tool's cutting edge. This work proposes a method that consists in developing a CNC program output code that allows one to process complex forms of stepped shafts with only one machine setup. The authors developed and justified a mathematical model of a technological system for mechanical processing with consideration for the resolution of tool movement at the stages of transition processes to assess the dynamical stability of a system in the process of manufacturing stepped surfaces of parts of “solid of revolution” type.

  8. Improvement of mechanical and tribological properties in steel surfaces by using titanium-aluminum/titanium-aluminum nitride multilayered system

    Energy Technology Data Exchange (ETDEWEB)

    Ipaz, L., E-mail: leoipazc@gmail.com [Thin Films Group, Physics departament, Universidad del Valle, Calle 13 100-00, A.A. 25360, Cali (Colombia); Caicedo, J.C. [Thin Films Group, Physics departament, Universidad del Valle, Calle 13 100-00, A.A. 25360, Cali (Colombia); Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Espinoza-Beltran, F.J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Fracc. Real de Juriquilla, C.P. 76230 (Mexico); Zambrano, G. [Thin Films Group, Physics departament, Universidad del Valle, Calle 13 100-00, A.A. 25360, Cali (Colombia)

    2012-02-01

    Improvement of mechanical and tribological properties on AISI D3 steel surfaces coated with [Ti-Al/Ti-Al-N]{sub n} multilayer systems deposited in various bilayer periods ({Lambda}) via magnetron co-sputtering pulsed d.c. method, from a metallic binary target; has been studied in this work exhaustively. The multilayer coatings were characterized in terms of structural, chemical, morphological, mechanical and tribological properties by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy, nanoindentation, pin-on-disc and scratch tests, respectively. The failure mode mechanisms were studied by optical microscopy. Results from X-ray diffraction analysis revealed that the crystal structure of TiAl/TiAlN multilayer coatings has a tetragonal and FCC NaCl-type lattice structures for Ti-Al and Ti-Al-N, respectively, i.e., it was found to be non-isostructural multilayers. An enhancement of both hardness and elastic modulus up to 29 GPa and 260 GPa, respectively, was observed as the bilayer periods ({Lambda}) in the coatings were decreased. The sample with a bilayer period ({Lambda}) of 25 nm and bilayer number n = 100 showed the lowest friction coefficient ({approx}0.28) and the highest critical load (45 N), corresponding to 2.7 and 1.5 times better than those values for the coating deposited with n = 1, respectively. These results indicate an enhancement of mechanical, tribological and adhesion properties, comparing to the [Ti-Al/Ti-Al-N]{sub n} multilayer systems with 1 bilayer at 26%, 63% and 33%, respectively. This enhancement in hardness and toughness for multilayer coatings could be attributed to the different mechanisms for layer formation with nanometric thickness such as the novel Ti-Al/Ti-Al-N effect and the number of interfaces that act as obstacles for the crack deflection and dissipation of crack energy.

  9. Surface effects and impurity production in tokamak machines

    International Nuclear Information System (INIS)

    Staib, P.; Staudenmaier, G.

    1978-01-01

    Plasma-wall interactions are presently investigated in two ways: a) The a priori assumption of a mechanism responsible for impurity release. Relevant experimental data can be used in a model and calculations made in order to understand the observed impurity behaviour in plasma. b) The comprehensive investigation of samples exposed to a plasma. Recent investigations have confirmed the earlier assumption that the interactions occur only in the topmost atomic layers of the wall, and so emphasize the major role of surface physics on this field. These investigations have further shown that besides atomic processes, such a desorption or sputtering, other processes occur, extending on a microscopic rather than an atomic scale. These are for example evaporation, arcing, and mechanical stress. Both aspects are discussed as far as possible in a quantitative way. The contribution of most probable processes is estimated using data available on flux and energy of particles and yields of single processes. The conclusion is reached that no process can be disregarded. Several processes seem to contribute to the impurity release and are different at different phases of the discharge. An interdependence between these processes is likely. (Auth.)

  10. Predicting the surface roughness in the dry machining of duplex stainless steel (DSS

    Directory of Open Access Journals (Sweden)

    G. Krolczyk

    2013-04-01

    Full Text Available This paper examines the influence of cutting parameters, namely cutting speed, feed and depth of cut onto surface roughness after DSS turning process. The study included developing a mathematical model to determine the surface roughness. Verification research has been carried out on CNC lathe; hence the test plan has been adjusted to the possibility of programmable machines controlling GE Fanuc Series 0-T. The comparison of results obtained by given experimental plan was performed in industrial company.

  11. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  12. The effects of hard particles on the surface quality when micro-cutting aluminum 6061 T6

    International Nuclear Information System (INIS)

    Ding, X; Lee, L C; Butler, D L; Cheng, C K

    2009-01-01

    Studies of micro-cutting have so far largely been carried out on single-phase materials. Due to the size effect, the workpiece material microstructure can have a significant influence on the cutting force, chip formation and surface quality. Previous investigations have shown that hard particles in materials such as aluminum alloy can play a significant role in the generation of defects such as cracks and voids on the work surface. This paper will examine the extent of the problem during the micro-cutting of Al6061 T6 and propose how it can be mitigated

  13. Study on effect of tool electrodes on surface finish during electrical discharge machining of Nitinol

    Science.gov (United States)

    Sahu, Anshuman Kumar; Chatterjee, Suman; Nayak, Praveen Kumar; Sankar Mahapatra, Siba

    2018-03-01

    Electrical discharge machining (EDM) is a non-traditional machining process which is widely used in machining of difficult-to-machine materials. EDM process can produce complex and intrinsic shaped component made of difficult-to-machine materials, largely applied in aerospace, biomedical, die and mold making industries. To meet the required applications, the EDMed components need to possess high accuracy and excellent surface finish. In this work, EDM process is performed using Nitinol as work piece material and AlSiMg prepared by selective laser sintering (SLS) as tool electrode along with conventional copper and graphite electrodes. The SLS is a rapid prototyping (RP) method to produce complex metallic parts by additive manufacturing (AM) process. Experiments have been carried out varying different process parameters like open circuit voltage (V), discharge current (Ip), duty cycle (τ), pulse-on-time (Ton) and tool material. The surface roughness parameter like average roughness (Ra), maximum height of the profile (Rt) and average height of the profile (Rz) are measured using surface roughness measuring instrument (Talysurf). To reduce the number of experiments, design of experiment (DOE) approach like Taguchi’s L27 orthogonal array has been chosen. The surface properties of the EDM specimen are optimized by desirability function approach and the best parametric setting is reported for the EDM process. Type of tool happens to be the most significant parameter followed by interaction of tool type and duty cycle, duty cycle, discharge current and voltage. Better surface finish of EDMed specimen can be obtained with low value of voltage (V), discharge current (Ip), duty cycle (τ) and pulse on time (Ton) along with the use of AlSiMg RP electrode.

  14. Optimal Machining Parameters for Achieving the Desired Surface Roughness in Turning of Steel

    Directory of Open Access Journals (Sweden)

    LB Abhang

    2012-06-01

    Full Text Available Due to the widespread use of highly automated machine tools in the metal cutting industry, manufacturing requires highly reliable models and methods for the prediction of output performance in the machining process. The prediction of optimal manufacturing conditions for good surface finish and dimensional accuracy plays a very important role in process planning. In the steel turning process the tool geometry and cutting conditions determine the time and cost of production which ultimately affect the quality of the final product. In the present work, experimental investigations have been conducted to determine the effect of the tool geometry (effective tool nose radius and metal cutting conditions (cutting speed, feed rate and depth of cut on surface finish during the turning of EN-31 steel. First and second order mathematical models are developed in terms of machining parameters by using the response surface methodology on the basis of the experimental results. The surface roughness prediction model has been optimized to obtain the surface roughness values by using LINGO solver programs. LINGO is a mathematical modeling language which is used in linear and nonlinear optimization to formulate large problems concisely, solve them, and analyze the solution in engineering sciences, operation research etc. The LINGO solver program is global optimization software. It gives minimum values of surface roughness and their respective optimal conditions.

  15. Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

    International Nuclear Information System (INIS)

    Kim, Hyungmo; Kim, Joonwon

    2010-01-01

    This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

  16. Surface modification of magnesium aluminum hydroxide nanoparticles with poly(methyl methacrylate) via one-pot in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Guo Xiaojun, E-mail: guoxj6906@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China); Zhao Leihua; Zhang Li; Li Jing [College of Chemistry and Chemical Engineering, Northwest Normal University, 967 Anning East Road, Lanzhou 730070 (China)

    2012-01-15

    Hydrophobic magnesium aluminum hydroxide composite particles (PMMA-MAH) were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of magnesium aluminum hydroxide(MAH) nanoparticles after a novel type of phosphate coupling agent (DN-27) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by DN-27 modification, followed by one-pot in situ polymerization on the particles surface using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and sodium dodecyl sulfate (SDS) as stabilizer to graft PMMA on the surface of DN-27-modified MAH particles. The obtained composite particles were characterized by field-emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD). The results show that the organic macromolecule PMMA could be successfully grafted on the surface of DN-27-modified MAH nanoparticles and the thermal stability of the PMMA-MAH composite particles had been improved. Compared with unmodified blank MAH sample, the product obtained with this method possesses better hydrophobic properties such as a higher water contact angle of 108 Degree-Sign and a well dispersion.

  17. In situ anodization of aluminum surfaces studied by x-ray reflectivity and electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Bertram, F.; Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E.; Zhang, F.; Pan, J.; Carlà, F.; Nilsson, J.-O.

    2014-01-01

    We present results from the anodization of an aluminum single crystal [Al(111)] and an aluminum alloy [Al 6060] studied by in situ x-ray reflectivity, in situ electrochemical impedance spectroscopy and ex situ scanning electron microscopy. For both samples, a linear increase of oxide film thickness with increasing anodization voltage was found. However, the slope is much higher in the single crystal case, and the break-up of the oxide film grown on the alloy occurs at a lower anodization potential than on the single crystal. The reasons for these observations are discussed as are the measured differences observed for x-ray reflectivity and electrochemical impedance spectroscopy.

  18. Electrochemical machining of internal built-up surfaces of large-sized vessels for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ryabchenko, N N; Pulin, V Ya [Vsesoyuznyj Proektno-Tekhnologicheskij Inst. Atomnogo Mashinostroeniya i Kotlostroeniya, Rostov-na-Donu (USSR)

    1977-01-01

    Electrochemical machining (ECM) has been employed for finishing of mechanically processed inner surfaces of large lateral parts of construction bodies with welded 0Kh18N10T steel overlayer. The finishing technology developed reduces the surface roughness from 10 mcm to the standard 2.5 mcm at the efficiency of machining of 2-4 m/sup 2/ per hour.

  19. Influence of cutting data on surface quality when machining 17-4 PH stainless steel

    Science.gov (United States)

    Popovici, T. D.; Dijmărescu, M. R.

    2017-08-01

    The aim of the research presented in this paper is to analyse the cutting data influence upon surface quality for 17-4 PH stainless steel milling machining. The cutting regime parameters considered for the experiments were established using cutting regimes from experimental researches or from industrial conditions as basis, within the recommended ranges. The experimental program structure was determined by taking into account compatibility and orthogonality conditions, minimal use of material and labour. The machined surface roughness was determined by measuring the Ra roughness parameter, followed by surface profile registration in the form of graphics which were saved on a computer with MarSurf PS1Explorer software. Based on Ra roughness parameter, maximum values were extracted from these graphics and the influence charts of the cutting regime parameters upon surface roughness were traced using Microsoft Excel software. After a thorough analysis of the resulting data, relevant conclusions were drawn, presenting the interdependence between the surface roughness of the machined 17-4 PH samples and the cutting data variation.

  20. Automated discovery and construction of surface phase diagrams using machine learning

    International Nuclear Information System (INIS)

    Ulissi, Zachary W.; Singh, Aayush R.; Tsai, Charlie

    2016-01-01

    Surface phase diagrams are necessary for understanding surface chemistry in electrochemical catalysis, where a range of adsorbates and coverages exist at varying applied potentials. These diagrams are typically constructed using intuition, which risks missing complex coverages and configurations at potentials of interest. More accurate cluster expansion methods are often difficult to implement quickly for new surfaces. We adopt a machine learning approach to rectify both issues. Using a Gaussian process regression model, the free energy of all possible adsorbate coverages for surfaces is predicted for a finite number of adsorption sites. Our result demonstrates a rational, simple, and systematic approach for generating accurate free-energy diagrams with reduced computational resources. Finally, the Pourbaix diagram for the IrO_2(110) surface (with nine coverages from fully hydrogenated to fully oxygenated surfaces) is reconstructed using just 20 electronic structure relaxations, compared to approximately 90 using typical search methods. Similar efficiency is demonstrated for the MoS_2 surface.

  1. Feedrate optimization in 5-axis machining based on direct trajectory interpolation on the surface using an open cnc

    OpenAIRE

    Beudaert , Xavier; Lavernhe , Sylvain; Tournier , Christophe

    2014-01-01

    International audience; In the common machining process of free-form surfaces, CAM software generates approximated tool paths because of the input tool path format of the industrial CNC. Then, marks on finished surfaces may appear due to non smooth feedrate planning during interpolation. The Direct Trajectory Interpolation on the Surface (DTIS) method allows managing the tool path geometry and the kinematical parameters to achieve higher productivity and a better surface quality. Machining ex...

  2. Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

    Science.gov (United States)

    Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

    2016-12-01

    Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

  3. Low Temperature Curing of Hydrogen Silsesquioxane Surface Coatings for Corrosion Protection of Aluminum

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Møller, Per

    2016-01-01

    Hydrogen Silsesquioxane (HSQ) has shown to be a promising precursor for corrosion protective glass coatings for metallic substrates due to the excellent barrier properties of the films, especially in the application of protective coatings for aluminum in the automotive industry where high chemica...

  4. Laser surface alloying of aluminum (AA1200) with Ni and SiC Powders

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2010-12-01

    Full Text Available . The dissociated C reacted with Al to form Al4C3. The addition of Ni resulted in the formation of the Al3Ni phase. A hardness increase of approximately four times that of aluminum AA1200 was achieved in the alloyed layer....

  5. Study on the fabrication of back surface reflectors in nano-crystalline silicon thin-film solar cells by using random texturing aluminum anodization

    Science.gov (United States)

    Shin, Kang Sik; Jang, Eunseok; Cho, Jun-Sik; Yoo, Jinsu; Park, Joo Hyung; Byungsung, O.

    2015-09-01

    In recent decades, researchers have improved the efficiency of amorphous silicon solar cells in many ways. One of the easiest and most practical methods to improve solar-cell efficiency is adopting a back surface reflector (BSR) as the bottom layer or as the substrate. The BSR reflects the incident light back to the absorber layer in a solar cell, thus elongating the light path and causing the so-called "light trapping effect". The elongation of the light path in certain wavelength ranges can be enhanced with the proper scale of BSR surface structure or morphology. An aluminum substrate with a surface modified by aluminum anodizing is used to improve the optical properties for applications in amorphous silicon solar cells as a BSR in this research due to the high reflectivity and the low material cost. The solar cells with a BSR were formed and analyzed by using the following procedures: First, the surface of the aluminum substrate was degreased by using acetone, ethanol and distilled water, and it was chemically polished in a dilute alkali solution. After the cleaning process, the aluminum surface's morphology was modified by using a controlled anodization in a dilute acid solution to form oxide on the surface. The oxidized film was etched off by using an alkali solution to leave an aluminum surface with randomly-ordered dimple-patterns of approximately one micrometer in size. The anodizing conditions and the anodized aluminum surfaces after the oxide layer had been removed were systematically investigated according to the applied voltage. Finally, amorphous silicon solar cells were deposited on a modified aluminum plate by using dc magnetron sputtering. The surfaces of the anodized aluminum were observed by using field-emission scanning electron microscopy. The total and the diffuse reflectances of the surface-modified aluminum sheets were measured by using UV spectroscopy. We observed that the diffuse reflectances increased with increasing anodizing voltage. The

  6. Surface structuring of boron doped CVD diamond by micro electrical discharge machining

    Science.gov (United States)

    Schubert, A.; Berger, T.; Martin, A.; Hackert-Oschätzchen, M.; Treffkorn, N.; Kühn, R.

    2018-05-01

    Boron doped diamond materials, which are generated by Chemical Vapor Deposition (CVD), offer a great potential for the application on highly stressed tools, e. g. in cutting or forming processes. As a result of the CVD process rough surfaces arise, which require a finishing treatment in particular for the application in forming tools. Cutting techniques such as milling and grinding are hardly applicable for the finish machining because of the high strength of diamond. Due to its process principle of ablating material by melting and evaporating, Electrical Discharge Machining (EDM) is independent of hardness, brittleness or toughness of the workpiece material. EDM is a suitable technology for machining and structuring CVD diamond, since boron doped CVD diamond is electrically conductive. In this study the ablation characteristics of boron doped CVD diamond by micro electrical discharge machining are investigated. Experiments were carried out to investigate the influence of different process parameters on the machining result. The impact of tool-polarity, voltage and discharge energy on the resulting erosion geometry and the tool wear was analyzed. A variation in path overlapping during the erosion of planar areas leads to different microstructures. The results show that micro EDM is a suitable technology for finishing of boron doped CVD diamond.

  7. Geometry and surface damage in micro electrical discharge machining of micro-holes

    Science.gov (United States)

    Ekmekci, Bülent; Sayar, Atakan; Tecelli Öpöz, Tahsin; Erden, Abdulkadir

    2009-10-01

    Geometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging.

  8. Machine integrated optical measurement of honed surfaces in presence of cooling lubricant

    International Nuclear Information System (INIS)

    Schmitt, R; Koenig, N; Zheng, H

    2011-01-01

    The measurement of honed surfaces is one of the most important tasks in tribology. Although many established techniques exist for texture characterization, such as SEM, tactile stylus or white-light interferometry, none of them is suited for a machine integrated measurement. Harsh conditions such as the presence of cooling lubricant or vibrations prohibit the use of commercial sensors inside a honing machine. Instead, machined engine blocks need time-consuming cleaning and preparation while taken out of the production line for inspection. A full inspection of all produced parts is hardly possible this way. Within this paper, an approach for a machine-integrated measurement is presented, which makes use of optical sensors for texture profiling. The cooling lubricant here serves as immersion medium. The results of test measurements with a chromatic-confocal sensor and a fiber-optical low-coherence interferometer show the potential of both measuring principles for our approach. Cooling lubricant temperature and flow, scanning speed and measurement frequency have been varied in the tests. The sensor with best performance will later be chosen for machine integration.

  9. Geometry and surface damage in micro electrical discharge machining of micro-holes

    International Nuclear Information System (INIS)

    Ekmekci, Bülent; Sayar, Atakan; Öpöz, Tahsin Tecelli; Erden, Abdulkadir

    2009-01-01

    Geometry and subsurface damage of blind micro-holes produced by micro electrical discharge machining (micro-EDM) is investigated experimentally to explore the relational dependence with respect to pulse energy. For this purpose, micro-holes are machined with various pulse energies on plastic mold steel samples using a tungsten carbide tool electrode and a hydrocarbon-based dielectric liquid. Variations in the micro-hole geometry, micro-hole depth and over-cut in micro-hole diameter are measured. Then, unconventional etching agents are applied on the cross sections to examine micro structural alterations within the substrate. It is observed that the heat-damaged segment is composed of three distinctive layers, which have relatively high thicknesses and vary noticeably with respect to the drilling depth. Crack formation is identified on some sections of the micro-holes even by utilizing low pulse energies during machining. It is concluded that the cracking mechanism is different from cracks encountered on the surfaces when machining is performed by using the conventional EDM process. Moreover, an electrically conductive bridge between work material and debris particles is possible at the end tip during machining which leads to electric discharges between the piled segments of debris particles and the tool electrode during discharging

  10. The effect of machining parameters on surface roughness during turning of stainless steel

    International Nuclear Information System (INIS)

    El-Belazi, Khalid M.

    1991-03-01

    Surface roughness is a direct consequence of the cutting tool action, its assessment and control represent an effective way by which the machining process can be studied. The control of surface roughness has become increasingly important during the last thirty years, because the quality of surface is extremely important for machined components that have been designed to stand to static and cyclic loads. This work has two major goals. The first is to develop a new theoretical model based on the assumption that the shape of the cutting tool nose is elliptical to evaluate the surface roughness parameters. The second is to investigate the effect of cutting speed, feed rate, overhang length, tool nose radius (circular sharp), and depth of cut on surface roughness of turned surfaces of austenitic stainless steel grade 12X18H10T. It was found from the theoretical part that the surface roughness values obtained from the elliptical model are much better than those obtained from the other models. It was found from the experimental work that the surface roughness values increase by increasing cutting speed, feed rate, depth of cut, and overhang length, and fluctuates when using cutting tools with various nose radii, during turning of the above mentioned steel by using a brazed carbide cutting tool. (author)

  11. Specific Features of Chip Making and Work-piece Surface Layer Formation in Machining Thermal Coatings

    Directory of Open Access Journals (Sweden)

    V. M. Yaroslavtsev

    2016-01-01

    Full Text Available A wide range of unique engineering structural and performance properties inherent in metallic composites characterizes wear- and erosion-resistant high-temperature coatings made by thermal spraying methods. This allows their use both in manufacturing processes to enhance the wear strength of products, which have to operate under the cyclic loading, high contact pressures, corrosion and high temperatures and in product renewal.Thermal coatings contribute to the qualitative improvement of the technical level of production and product restoration using the ceramic composite materials. However, the possibility to have a significantly increased product performance, reduce their factory labour hours and materials/output ratio in manufacturing and restoration is largely dependent on the degree of the surface layer quality of products at their finishing stage, which is usually provided by different kinds of machining.When machining the plasma-sprayed thermal coatings, a removing process of the cut-off layer material is determined by its distinctive features such as a layered structure, high internal stresses, low ductility material, high tendency to the surface layer strengthening and rehardening, porosity, high abrasive properties, etc. When coatings are machined these coating properties result in specific characteristics of chip formation and conditions for formation of the billet surface layer.The chip formation of plasma-sprayed coatings was studied at micro-velocities using an experimental tool-setting microscope-based setup, created in BMSTU. The setup allowed simultaneous recording both the individual stages (phases of the chip formation process and the operating force factors.It is found that formation of individual chip elements comes with the multiple micro-cracks that cause chipping-off the small particles of material. The emerging main crack in the cut-off layer of material leads to separation of the largest chip element. Then all the stages

  12. Influence of Cooling Lubricants on the Surface Roughness and Energy Efficiency of the Cutting Machine Tools

    Directory of Open Access Journals (Sweden)

    Jersák J.

    2017-08-01

    Full Text Available The Technical University of Liberec and Brandenburg University of Technology Cottbus-Senftenberg investigated the influence of cooling lubricants on the surface roughness and energy efficiency of cutting machine tools. After summarizing the achieved experimental results, the authors conclude that cooling lubricants extensively influence the cutting temperature, cutting forces and energy consumption. Also, it is recognizable that cooling lubricants affect the cutting tools lifetime and the workpiece surface quality as well. Furthermore, costs of these cooling lubricants and the related environmental burden need to be considered. A current trend is to reduce the amount of lubricants that are used, e.g., when the Minimum Quantity Lubrication (MQL technique is applied. The lubricant or process liquid is thereby transported by the compressed air in the form of an aerosol to the contact area between the tool and workpiece. The cutting process was monitored during testing by the three following techniques: lubricant-free cutting, cutting with the use of a lubricant with the MQL technique, and only utilizing finish-turning and finish-face milling. The research allowed the authors to monitor the cutting power and mark the achieved surface quality in relation to the electrical power consumption of the cutting machine. In conclusions, the coherence between energy efficiency of the cutting machine and the workpiece surface quality regarding the used cooling lubricant is described.

  13. Influence of repetitive pulsed laser irradiation on the surface characteristics of an aluminum alloy in the melting regime

    International Nuclear Information System (INIS)

    Choi, Sung Ho; Jhang, Kyung Young

    2015-01-01

    We have investigated the influence of repetitive near-infrared (NIR) pulsed laser shots in the melting regime on the surface characteristics of an aluminum 6061-T6 alloy. Characteristics of interest include surface morphology, surface roughness, and surface hardness in the melted zone as well as the size of the melted zone. For this study, the proper pulse energy for inducing surface melting at one shot is selected using numerical simulations that calculate the variation in temperature at the laser beam spot for various input pulse energies in order to find the proper pulse energy for raising the temperature to the melting point. In this study, 130 mJ was selected as the input energy for a Nd:YAG laser pulse with a duration of 5 ns. The size of the melted zone measured using optical microscopy (OM) increased logarithmically with an increasing shot number. The surface morphology observed by scanning electron microscopy (SEM) clearly showed a re-solidified microstructure evolution after surface melting. The surface roughness and hardness were measured by atomic force microscopy (AFM) and nano-indentation, respectively. The surface roughness showed almost no variation due to the surface texturing after laser shots over 10. The hardness inside the melted zone was lower than that outside the zone because the β'' phase was transformed to a β phase or dissolved into a matrix.

  14. Investigation and Evaluation on Influence of Machining (CNC Conditions on Surface Quality of Paulownia Wood

    Directory of Open Access Journals (Sweden)

    Mohammad Aghajani

    2012-01-01

    Full Text Available The aim of this study was to investigate the effective factors on surface quality of paulownia wood during machining by advanced computer numerical controled (CNC machine. For this aim paulownia logs were provided and were converted to proper sizes (2.5 x 10 x 15 cm and then air dried. The Variable of this study were cutting speed (8.37 and 15.07 m/s, feeding rate (6 and 12 m/min, cutting depth (1and 5 mm, cutting method (down and up-milling and cutting pattern (tangential and radial. Roughness of cut specimens edge were evaluated by profilometer method according to ISO 13565 standard. For evaluation of surface quality, average roughness (Ra, maximum roughness (R max, valley roughness (Rv and peak roughness (Rp were used. Degrees of effectiveness of the parameters were evaluated by fractional factorial design as completely random design at confidence level of 95%. The result showed that cutting speed, cutting method and feed rate are influencive factors on surface quality of machined specimens and their effects were significant. With increasing cutting speed and decreasing feeding rate the roughness decreased and surface quality improved. In up-milling cutting method, degree of roughness was higher and consequently surface quality was inferior. It is to be noted that cutting method in comparison to other factors had the high influence on surface quality. The rest variables did now have independent influence on surface quality at 95% Confidence level. This study for achieving the optimum surface quality recommends that cutting speed of 15.07 m/s, feeding rate of 6 m/min, cutting method of down-milling and cutting depth of 1 mm for tangential cross section.

  15. Hardness and structure changes at surface in electrical discharge machined steel C 3840

    International Nuclear Information System (INIS)

    Karastojkovic, Z.; Janjusevic, Z.

    2003-01-01

    The electrical discharge machining (EDM) of both hard and soft materials became an important technique in industrial applications. This technique has an advantage in producing of structural/tool parts of complex geometry. The EDM is based on electrical phenomena, when the treated surface undergoes to erosion. The first step in EDM, the melting of thin surface layer, frequently is neglected. In this paper the changes of hardness and structure at surface layer, after EDM is applied on steel C 3840, will be discussed. The steel C- 3840 was quenched and tempered to hardness of 63 HRC, at surface, and than machined by electrical discharging. The changed, white, layer is just a product of melting and decarburization processes. The white layer is registered at surface by using a metallographic investigation. Hardness profile is measured from surface to the interior of material. The achievement of local high temperatures during EDM is resulting on melt and erosion of material. Besides of these effects, during EDM were happened some minor but not a neglectible effects, primary on structure changes on treated surface. It would be expected that melting, even an evaporation of melted metal, and further the phase transformation have an important influence on the starting structure. (Original)

  16. Analysis of surface roughening behavior of 6063 aluminum alloy by tensile testing of a trapezoidal uniaxial specimen

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang, Xiaosong, E-mail: hitxswang@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Yuan, Shijian [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

    2016-08-30

    To determine the quantitative relationship between surface roughness and strain, the surface roughening behavior of a 6063 aluminum alloy tube was examined by tensile testing of a trapezoidal uniaxial specimen, that can provide a continuous strain distribution after tensile deformation. The surface roughness was measured using a laser scanning confocal microscope to reflect the degree of roughening. The microstructure and surface morphology were examined using electron back-scattered diffraction and in-situ scanning electron microscopy to determine the grain orientation and surface topography evolution. The surface roughness increased with strain when the strain was less than 0.067 and then decreased slightly, with a maximum surface roughness of 23.73 µm. Inhomogeneous deformation at the grain boundaries and inside the grains was enhanced with increasing strain, resulting in an increase of surface roughness when the strain was below a critical value. As the strain increased, a greater number of slip systems contributed to the further deformation. Thus, the strain became more homogeneous, and accordingly, the surface roughness slightly decreased.

  17. A hybrid Taguchi-artificial neural network approach to predict surface roughness during electric discharge machining of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sanjeev; Batish, Ajay [Thapar University, Patiala (India); Singh, Rupinder [GNDEC, Ludhiana (India); Singh, T. P. [Symbiosis Institute of Technology, Pune (India)

    2014-07-15

    In the present study, electric discharge machining process was used for machining of titanium alloys. Eight process parameters were varied during the process. Experimental results showed that current and pulse-on-time significantly affected the performance characteristics. Artificial neural network coupled with Taguchi approach was applied for optimization and prediction of surface roughness. The experimental results and the predicted results showed good agreement. SEM was used to investigate the surface integrity. Analysis for migration of different chemical elements and formation of compounds on the surface was performed using EDS and XRD pattern. The results showed that high discharge energy caused surface defects such as cracks, craters, thick recast layer, micro pores, pin holes, residual stresses and debris. Also, migration of chemical elements both from electrode and dielectric media were observed during EDS analysis. Presence of carbon was seen on the machined surface. XRD results showed formation of titanium carbide compound which precipitated on the machined surface.

  18. Surface Characteristics of Machined NiTi Shape Memory Alloy: The Effects of Cryogenic Cooling and Preheating Conditions

    Science.gov (United States)

    Kaynak, Y.; Huang, B.; Karaca, H. E.; Jawahir, I. S.

    2017-07-01

    This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish ( A f) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.

  19. Automatic fitting of conical envelopes to free-form surfaces for flank CNC machining

    OpenAIRE

    Bo P.; Bartoň M.; Pottmann H.

    2017-01-01

    We propose a new algorithm to detect patches of free-form surfaces that can be well approximated by envelopes of a rotational cone under a rigid body motion. These conical envelopes are a preferable choice from the manufacturing point of view as they are, by-definition, manufacturable by computer numerically controlled (CNC) machining using the efficient flank (peripheral) method with standard conical tools. Our geometric approach exploits multi-valued vector fields that consist of vectors in...

  20. Novel strategy in increasing stability and corrosion resistance for super-hydrophobic coating on aluminum alloy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yin Bo [Department of Applied Physics, Chongqing University, Chongqing, 400044 (China); Fang Liang, E-mail: fangliangcqu@yahoo.com.cn [Department of Applied Physics, Chongqing University, Chongqing, 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing, 400044 (China); Tang Anqiong; Huang Qiuliu; Hu Jia; Mao Jianhui [Department of Applied Physics, Chongqing University, Chongqing, 400044 (China); Bai, Ge; Bai, Huan [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing, 400044 (China)

    2011-10-15

    A novel super-hydrophobic coating was prepared by chemical modification on the anodized aluminum alloy surface. The surface structure was characterized by water contact angle measurement, scanning electron microscopy (SEM), and the composition was measured by X-ray photoelectron spectroscopy (XPS). The corrosion behavior of the super-hydrophobic coating was evaluated by the polarization curve and the electrochemical impedance spectroscopy (EIS). It was found that the static water contact angle on the surface of super-hydrophobic coating was as high as 167.7 {+-} 1.2 deg., and the sliding angle was 5 deg. The super-hydrophobic coating resulted in excellent corrosion resistance property and the super-hydrophobic coating showed a good stability.

  1. The fabrication of Ag nanoflake arrays via self-assembly on the surface of an anodic aluminum oxide template

    International Nuclear Information System (INIS)

    Li Xueming; Dong Kun; Tang Libin; Wu, Yongjun; Yang Peizhi; Zhang Pengxiang

    2010-01-01

    Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications.

  2. The fabrication of Ag nanoflake arrays via self-assembly on the surface of an anodic aluminum oxide template

    Science.gov (United States)

    Li, Xueming; Dong, Kun; Tang, Libin; Wu, Yongjun; Yang, Peizhi; Zhang, Pengxiang

    2010-02-01

    Vertical-aligned Ag nanoflake arrays are fabricated on the surface of an anodic aluminum oxide (AAO) template under a hydrothermal condition for the first time. The porous surface of AAO templates and the precursor solution may play key roles in the process of fabricating Ag nanoflakes. The rim of pores can provide many active sites for nucleation and growth, and then nanoflake arrays gradually form through self-assembly of Ag on the surface of AAO membranes. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and a growth mechanism of nanoflake is deduced. This work demonstrates that it is possible to make ordered nanoarrays without dissolving templates using the hydrothermal method, and this interesting Ag nanoflake arrays may provide a wider range of nanoscale applications.

  3. An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

    Science.gov (United States)

    Jalili, M.; Rostami, M.; Ramezanzadeh, B.

    2015-02-01

    Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

  4. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    OpenAIRE

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-01-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The de...

  5. Preparation and Surface Analysis of PPY/SDBS Films on Aluminum Substrates

    Directory of Open Access Journals (Sweden)

    Lisete C. Scienza

    2001-09-01

    Full Text Available Polypyrrole films were generated on high purity aluminum substrates under anodic polarization from aqueous electrolytes comprised of pyrrole and sodium dodecylbenzene sulfonate. The methods employed to characterize the polymer films included scanning electron microscopy, Fourier-transform infrared and X-photoelectron spectroscopy and X-ray diffraction. PPY/SDBS films revealed nodular morphology with occasional appearing of "dendrites", high level of protonation, excess of counter-anions ([S]/[N] > [N+]/[N] and high degrees of disorder.

  6. Study of cutting speed on surface roughness and chip formation when machining nickel-based alloy

    International Nuclear Information System (INIS)

    Khidhir, Basim A.; Mohamed, Bashir

    2010-01-01

    Nickel- based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature. The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects of cutting speed on surface roughness have been investigated. This study explores the types of wear caused by the effect of cutting speed on coated and uncoated carbide inserts. In addition, the effect of burr formation is investigated. The chip burr is found to have different shapes at lower speeds. Triangles and squares have been noticed for both coated and uncoated tips as well. The conclusion from this study is that the transition from thick continuous chip to wider discontinuous chip is caused by different types of inserts. The chip burr has a significant effect on tool damage starting in the line of depth-of-cut. For the coated insert tips, the burr disappears when the speed increases to above 150 m/min with the improvement of surface roughness; increasing the speed above the same limit for uncoated insert tips increases the chip burr size. The results of this study showed that the surface finish of nickel-based alloy is highly affected by the insert type with respect to cutting speed changes and its effect on chip burr formation and tool failure

  7. Fabrication of a novel aluminum surface covered by numerous high-aspect-ratio anodic alumina nanofibers

    Science.gov (United States)

    Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2015-11-01

    The formation behavior of anodic alumina nanofibers via anodizing in a concentrated pyrophosphoric acid under various conditions was investigated using electrochemical measurements and SEM/TEM observations. Pyrophosphoric acid anodizing at 293 K resulted in the formation of numerous anodic alumina nanofibers on an aluminum substrate through a thin barrier oxide and honeycomb oxide with narrow walls. However, long-term anodizing led to the chemical dissolution of the alumina nanofibers. The density of the anodic alumina nanofibers decreased as the applied voltage increased in the 10-75 V range. However, active electrochemical dissolution of the aluminum substrate occurred at a higher voltage of 90 V. Low temperature anodizing at 273 K resulted in the formation of long alumina nanofibers measuring several micrometers in length, even though a long processing time was required due to the low current density during the low temperature anodizing. In contrast, high temperature anodizing easily resulted in the formation and chemical dissolution of alumina nanofibers. The structural nanofeatures of the anodic alumina nanofibers were controlled by choosing of the appropriate electrochemical conditions, and numerous high-aspect-ratio alumina nanofibers (>100) can be successfully fabricated. The anodic alumina nanofibers consisted of a pure amorphous aluminum oxide without anions from the employed electrolyte.

  8. Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cudzinovic, M.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    A process for forming highly reflective aluminum back contacts with low contact resistance to silicon solar cells is described. By controlling the process conditions, it is possible to vary the silicon/aluminum interface from a specular to a diffuse reflector while maintaining a high interface reflectance. The specular interface is found to be a uniform silicon/aluminum alloy layer a few angstroms thick that has epitaxially regrown on the silicon. The diffuse interface consists of randomly distributed (111) pyramids produced by crystallographic out-diffusion of the bulk silicon. The light trapping ability of the diffuse contact is found to be close to the theoretical limit. Both types of contacts are found to have specific contact resistivities of 10{sup {minus}5} {Omega}-cm{sup 2}. The process for forming the contacts involves illuminating the devices with tungsten halogen lamps. The process is rapid (under 100 s) and low temperature (peak temperature < 580{degrees}C), making it favorable for commercial solar cell fabrication.

  9. DIAGNOSTICS OF WORKPIECE SURFACE CONDITION BASED ON CUTTING TOOL VIBRATIONS DURING MACHINING

    Directory of Open Access Journals (Sweden)

    Jerzy Józwik

    2015-05-01

    Full Text Available The paper presents functional relationships between surface geometry parameters, feed and vibrations level in the radial direction of the workpiece. Time characteristics of the acceleration of cutting tool vibration registered during C45 steel and stainless steel machining for separate axes (X, Y, Z were presented as a function of feedrate f. During the tests surface geometric accuracy assessment was performed and 3D surface roughness parameters were determined. The Sz parameter was selected for the analysis, which was then collated with RMS vibration acceleration and feedrate f. The Sz parameter indirectly provides information on peak to valley height and is characterised by high generalising potential i.e. it is highly correlated to other surface and volume parameters of surface roughness. Test results presented in this paper may constitute a valuable source of information considering the influence of vibrations on geometric accuracy of elements for engineers designing technological processes.

  10. 2D Analytical Modeling of Magnetic Vector Potential in Surface Mounted and Surface Inset Permanent Magnet Machines

    Directory of Open Access Journals (Sweden)

    A. Jabbari

    2017-12-01

    Full Text Available A 2D analytical method for magnetic vector potential calculation in inner rotor surface mounted and surface inset permanent magnet machines considering slotting effects, magnetization orientation and winding layout has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in quasi- Cartesian coordinate by using sub-domain method and hyperbolic functions. The developed method is applied on the performance computation of two prototypes surface mounted permanent magnet motors and two prototypes surface inset permanent magnet motors. A radial and a parallel magnetization orientation is considered for each type of motor. The results of these models are validated through FEM method.

  11. Secondary electron emission influenced by oxidation on the aluminum surface: the roles of the chemisorbed oxygen and the oxide layer

    Science.gov (United States)

    Li, Jiangtao; Hoekstra, Bart; Wang, Zhen-Bin; Qiu, Jie; Pu, Yi-Kang

    2018-04-01

    A relationship between the apparent secondary electron yield ({γ }{{se}}) and the oxygen coverage/oxide layer thickness on an aluminum cathode is obtained in an experiment under a controlled environment. The apparent secondary electron yield ({γ }{{se}}) is deduced from the breakdown voltage between two parallel plate electrodes in a 360 mTorr argon environment using a simple Townsend breakdown model with the assumption that the variation of the apparent secondary electron yield is dominated by the variation of the argon ion induced processes. The oxygen coverage/oxide layer thickness on the aluminum cathode is measured by a semi in situ x-ray photoemission spectroscopy equipment which is directly attached to the discharge chamber. It is found that three phases exist: (1) in the monomonolayer regime, as the oxygen coverage increases from 0 to 0.3, {γ }{{se}} decreases by nearly 40 % , (2) as the oxygen coverage increases from 0.3 to 1, {γ }{{se}} keeps nearly constant, (3) as the oxide layer thickness increases from about 0.3 nm to about 1.1 nm, {γ }{{se}} increases by 150 % . We propose that, in the submonolayer regime, the chemisorbed oxygen on the aluminum surface causes the decrease of {γ }{{se}} by creating a local potential barrier, which reduces the Auger neutralization rate and the energy gained by the Auger electrons. In the multilayer regime, as the oxide layer grows in thickness, there are three proposed mechanisms which cause the increase of {γ }{{se}}: (1) the work function decreases; (2) resonance neutralization and Auger de-excitation may exist. This is served as another channel for secondary electron production; (3) the kinetic energy of Auger electrons is increased on average, leading to a higher probability for electrons to overcome the surface potential barrier.

  12. X-ray study of surface layers of tungsten monocrystals after electroerosion machining

    International Nuclear Information System (INIS)

    Aleshina, S.A.; Baranov, Yu.V.; Smirnov, I.S.; Marchuk, A.I.

    1981-01-01

    The presence of polycrystal surface layer, approximately 10 μm thick in subjacent layers and the presence of highly developed block structure which is the result of high-temperature effect of electroerosion machining are detected. Angles of disorientation between blocks, which constitute tens of angular minutes, are evaluated using the method of X-ray topography. According to broadening of profile of X-ray diffraction lines analysis of fine crystal structure of the surface layers is conducted. It is shown that the broadening of diffraction lines is mainly connected with the presence of coherent scat-- tering regions

  13. Analysis of Material Removal and Surface Characteristics in Machining Multi Walled Carbon Nanotubes Filled Alumina Composites by WEDM Process

    Directory of Open Access Journals (Sweden)

    Annebushan Singh Meinam

    2017-01-01

    Full Text Available The reinforcement of ceramic materials with electrically conductive particles increases the overall conductivity of the ceramic material. This allows the ceramic material to be more readily machined using wire electrical discharge machining process. The current work is an approach to identify the machinability of multi walled carbon nanotubes filled alumina composites in wire electrical discharge machining process. Alumina samples of 5 vol. % and 10 vol. % multi walled carbon nanotubes are machined and analysed for material removal rate and the surface characteristics. An increase in material removal rate is observed with increase in filler concentrations. At the same time, better surface roughness is observed. The surface characteristics of composite alumina are further compared with Monel 400 alloy. It has been observed that spalling action is the dominating material removal mechanism for alumina composites, while melting and evaporation is for the Monel 400 alloy.

  14. Response Surface Design Model to Predict Surface Roughness when Machining Hastelloy C-2000 using Uncoated Carbide Insert

    International Nuclear Information System (INIS)

    Razak, N H; Rahman, M M; Kadirgama, K

    2012-01-01

    This paper presents to develop of the response surface design model to predict the surface roughness for end-milling operation of Hastelloy C-2000 using uncoated carbide insert. Mathematical model is developed to study the effect of three input cutting parameters includes the feed rate, axial depth of cut and cutting speed. Design of experiments (DOE) was implemented with the aid of the statistical software package. Analysis of variance (ANOVA) has been performed to verify the fit and adequacy of the developed mathematical model. The result shows that the feed rate gave the more effect on the both prediction values of Ra compared to the cutting speed and axial depth of cut. SEM and EDX analyses were performed in different cutting conditions. It can be concluded that the feed rate and cutting force give the higher impact to influence the machining characteristics of surface roughness. Thus, the optimizing the cutting conditions are essential in order to improve the surface roughness in machining of Hastlelloy C-2000.

  15. Experimental Investigation of Surface Layer Properties of High Thermal Conductivity Tool Steel after Electrical Discharge Machining

    Directory of Open Access Journals (Sweden)

    Rafał Świercz

    2017-12-01

    Full Text Available New materials require the use of advanced technology in manufacturing complex shape parts. One of the modern materials widely used in the tool industry for injection molds or hot stamping dies is high conductivity tool steel (HTCS 150. Due to its hardness (55 HRC and thermal conductivity at 66 W/mK, this material is difficult to machine by conventional treatment and is being increasingly manufactured by nonconventional technology such as electrical discharge machining (EDM. In the EDM process, material is removed from the workpiece by a series of electrical discharges that cause changes to the surface layers properties. The final state of the surface layer directly influences the durability of the produced elements. This paper presents the influence of EDM process parameters: discharge current Ic and the pulse time ton on surface layer properties. The experimental investigation was carried out with an experimental methodology design. Surface layers properties including roughness 3D parameters, the thickness of the white layer, heat affected zone, tempered layer and occurring micro cracks were investigated and described. The influence of the response surface methodology (RSM of discharge current Ic and the pulse time ton on the thickness of the white layer and roughness parameters Sa, Sds and Ssc were described and established.

  16. Controlling the Adhesion of Superhydrophobic Surfaces Using Electrolyte Jet Machining Techniques

    Science.gov (United States)

    Yang, Xiaolong; Liu, Xin; Lu, Yao; Zhou, Shining; Gao, Mingqian; Song, Jinlong; Xu, Wenji

    2016-01-01

    Patterns with controllable adhesion on superhydrophobic areas have various biomedical and chemical applications. Electrolyte jet machining technique (EJM), an electrochemical machining method, was firstly exploited in constructing dimples with various profiles on the superhydrophobic Al alloy surface using different processing parameters. Sliding angles of water droplets on those dimples firstly increased and then stabilized at a certain value with the increase of the processing time or the applied voltages of the EJM, indicating that surfaces with different adhesion force could be obtained by regulating the processing parameters. The contact angle hysteresis and the adhesion force that restricts the droplet from sliding off were investigated through experiments. The results show that the adhesion force could be well described using the classical Furmidge equation. On account of this controllable adhesion force, water droplets could either be firmly pinned to the surface, forming various patterns or slide off at designed tilting angles at specified positions on a superhydrophobic surface. Such dimples on superhydrophopbic surfaces can be applied in water harvesting, biochemical analysis and lab-on-chip devices. PMID:27046771

  17. Surface and elemental alterations of dental alloys induced by electro discharge machining (EDM).

    Science.gov (United States)

    Zinelis, Spiros

    2007-05-01

    To evaluate the surface and elemental alterations induced by electro discharge machining (EDM) on the surface of dental cast alloys used for the fabrication of implant retained meso- and super-structures. A completed cast model of an arch that received dental implants was used for the preparation of six wax patterns which were divided into three groups (Au, Co and Ti). The wax patterns of the Au and Co groups were invested with conventional phosphate-bonded silica-based investment material and the Ti group with magnesia-based investment material. The investment rings of the Au and Co groups were cast with an Au-Ag alloy (Stabilor G) and a Co-Cr base alloy (Okta C), respectively, while the investment rings of group Ti were cast with cp Ti (Biotan). One casting of each group was subjected to electro discharge machining (EDM); the other was conventionally ground and polished. The surface morphology and the elemental compositions of conventionally and EDM-finished surfaces were studied by SEM/X-ray EDS analysis. Six spectra were collected from each surface employing the area scan mode and the mean value of each element between conventionally and EDM-finished surfaces was statistically analyzed by t-test (a=0.05). Then the specimens of each group were cut perpendicular to their longitudinal axis and after metallographic grinding and polishing the cross-sections studied under the SEM. The EDM surfaces showed a significant increase in C due to the decomposition of the dielectric fluid during spark erosion. Moreover, a significant Cu uptake was noted on these surfaces from the decomposition of the Cu electrodes used for EDM. Cross-sectional analysis showed that all alloys developed a superficial zone (recast layer) varying from 2 microm for Au-Ag to 10 microm for Co-Cr alloy. The elemental composition of dental alloy surfaces is significantly altered after EDM treatment.

  18. Response surface modelling of tool electrode wear rate and material removal rate in micro electrical discharge machining of Inconel 718

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    conductivity and high strength causing it extremely difficult tomachine. Micro-Electrical Discharge Machining (Micro-EDM) is a non-conventional method that has a potential toovercome these restrictions for machining of Inconel 718. Response Surface Method (RSM) was used for modelling thetool Electrode Wear...

  19. Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment.

    Science.gov (United States)

    Boinovich, Ludmila B; Emelyanenko, Alexandre M; Modestov, Alexander D; Domantovsky, Alexandr G; Emelyanenko, Kirill A

    2015-09-02

    We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

  20. Advances in aluminum anodizing

    Science.gov (United States)

    Dale, K. H.

    1969-01-01

    White anodize is applied to aluminum alloy surfaces by specific surface preparation, anodizing, pigmentation, and sealing techniques. The development techniques resulted in alloys, which are used in space vehicles, with good reflectance values and excellent corrosive resistance.

  1. The machined surface of magnesium AZ31 after rotary turning at air cooling condition

    Science.gov (United States)

    Akhyar, G.; Purnomo, B.; Hamni, A.; Harun, S.; Burhanuddin, Y.

    2018-04-01

    Magnesium is a lightweight metal that is widely used as an alternative to iron and steel. Magnesium has been applied in the automotive industry to reduce the weight of a component, but the machining process has the disadvantage that magnesium is highly flammable because it has a low flash point. High temperature can cause the cutting tool wear and contributes to the quality of the surface roughness. The purpose of this study is to obtain the value of surface roughness and implement methods of rotary cutting tool and air cooling output vortex tube cooler to minimize the surface roughness values. Machining parameters that is turning using rotary cutting tool at speed the workpiece of (Vw) 50, 120, 160 m/min, cutting speed of rotary tool of (Vt) 25, 50, 75 m/min, feed rate of (f) 0.1, 0.15, 0.2 mm/rev, and depth of cut of 0.3 mm. Type of tool used is a carbide tool diameter of 16 mm and air cooling pressure of 6 bar. The results show the average value of the lowest surface roughness on the speed the workpiece of 80 m/min, cutting speed of rotary tool of 50 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm. While the average value of the highest surface roughness on the speed the workpiece of 160 m/min, cutting speed of rotary tool of 50 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm. The influence of machining parameters concluded the higher the speed of the workpiece the surface roughness value higher. Otherwise the higher cutting speed of rotary tool then the lower the surface roughness value. The observation on the surface of the rotary tool, it was found that no uniform tool wear which causes non-uniform surface roughness. The use of rotary cutting tool contributing to lower surface roughness values generated.

  2. Silver nanoparticles deposited on anodic aluminum oxide template using magnetron sputtering for surface-enhanced Raman scattering substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wong-ek, Krongkamol [Nanoscience and Technology Program, Chulalongkorn University, Bangkok 10330 (Thailand); Eiamchai, Pitak; Horprathum, Mati; Patthanasettakul, Viyapol [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Limnonthakul, Puenisara [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Chindaudom, Pongpan [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand); Nuntawong, Noppadon, E-mail: noppadon.nuntawong@nectec.or.t [National Electronics and Computer Technology Center, 112 Thailand Science Park, Phahonyothin Rd., Klong Luang, Pathumthani 12120 (Thailand)

    2010-09-30

    Low-cost and highly sensitive surface-enhanced Raman scattering (SERS) substrates have been fabricated by a simple anodizing process and a magnetron sputtering deposition. The substrates, which consist of silver nanoparticles embedded on anodic aluminum oxide (AAO) templates, are investigated by a scanning electron microscope and a confocal Raman spectroscopy. The SERS activities are demonstrated by Raman scattering from adsorbed solutions of methylene blue and pyridine on the SERS substrate surface. The most optimized SERS substrate contains the silver nanoparticles, with a size distribution of 10-30 nm, deposited on the AAO template. From a calculation, the SERS enhancement factor is as high as 8.5 x 10{sup 7}, which suggests strong potentials for direct applications in the chemical detection and analyses.

  3. Reaction of Tri-methylaluminum on Si (001) Surface for Initial Aluminum Oxide Thin-Film Growth

    International Nuclear Information System (INIS)

    Kim, Dae Hee; Kim, Dae Hyun; Jeong, Yong Chan; Seo, Hwa Il; Kim, Yeong Cheol

    2010-01-01

    We studied the reaction of tri-methylaluminum (TMA) on hydroxyl (OH)-terminated Si (001) surfaces for the initial growth of aluminum oxide thin-films using density functional theory. TMA was adsorbed on the oxygen atom of OH due to the oxygen atom's lone pair electrons. The adsorbed TMA reacted with the hydrogen atom of OH to produce a di-methylaluminum group (DMA) and methane with an energy barrier of 0.50 eV. Low energy barriers in the range of 0 - 0.11 eV were required for DMA migration to the inter-dimer, intra-dimer, and inter-row sites on the surface. A unimethylaluminum group (UMA) was generated at each site with low energy barriers in the range of 0.21 - 0.25 eV. Among the three sites, the inter-dimer site was the most probable for UMA formation

  4. Electrodeposition of polypyrrole films on aluminum surfaces from a p-toluene sulfonic acid medium

    Directory of Open Access Journals (Sweden)

    Andréa Santos Liu

    2009-01-01

    Full Text Available Electrodeposition of polypyrrole films on aluminum from aqueous solutions containing p-toluene sulfonic acid and pyrrole was performed by cyclic voltammetry and galvanostatic technique. The influence of applied current density on the morphology of the films was studied by Scanning Electron Microscopy. The films displayed a cauliflower-like structure consisting of micro-spherical grains. This structure is related to dopand intercalation in the polymeric chain. Films deposited at higher current density were more susceptible to the formation of pores and defects along the polymeric chain than films deposited at lower current density. These pores allow the penetration of aggressive species, thereby favoring the corrosion process.

  5. Inspecting a research reactor's control rod surface for pitting using a machine vision

    International Nuclear Information System (INIS)

    Tokuhiro, Akira T.; Vadakattu, Shreekanth

    2005-01-01

    Inspection for pits on the control rod is performed to study the degradation of the control rod material which helps estimating the service life of the control rod at UMR nuclear reactor (UMRR). This inspection task is visually inspected and recorded subjectively. The conventional visual inspection to identify pits on the control rod surface can be automated using machine vision technique. Since the in-service control rods were not available to capture images and measure number of pits and size of the pits, the applicability of machine vision method was applied on SAE 1018 steel coupons immersed in oxygen saturated de-ionized water at 30deg, 50deg and 70deg. Images were captured after each test cycle at different light intensity to reveal surface topography of the coupon surface and analyzed for number of pits and pit size using EPIX XCAP-Std software. The captured and analyzed images provided quantitative results for the steel coupons and demonstrated that the method can be applied for identifying pits on control rod surface in place of conventional visual inspection. (author)

  6. BONDING ALUMINUM METALS

    Science.gov (United States)

    Noland, R.A.; Walker, D.E.

    1961-06-13

    A process is given for bonding aluminum to aluminum. Silicon powder is applied to at least one of the two surfaces of the two elements to be bonded, the two elements are assembled and rubbed against each other at room temperature whereby any oxide film is ruptured by the silicon crystals in the interface; thereafter heat and pressure are applied whereby an aluminum-silicon alloy is formed, squeezed out from the interface together with any oxide film, and the elements are bonded.

  7. Characterization of surface layers of aluminum alloys for automobile body panels; Jidoshayo aluminium gokin no hyomen kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, K; Takagi, Y [Nippon Steel Corp., Tokyo (Japan)

    1996-03-29

    This paper reports analytical examples, on an oxidized film on the surface of aluminum alloys for automobiles, using the conventional method for a surface analysis or a new method entirely different from it. For example, (1) a new method was proposed which evaluated the thickness of MgO layers on the surface of Al-Mg alloy by means of a colorimeter. In the case where the thickness of the oxidized film was several tens of nanometers or less, the chromatic value of L, b, etc., and the thickness of the films were in one-to-one correspondence to each other; therefore, the MgO film was easily estimated non-destructively by measuring the chromatic values of the surface. (2) An analysis was made on the state of adhesion of the organic matters in the oxidized film on Al-Mg-Si alloy by means of an angle-resolved XPS (X-ray photoelectron spectroscopy) depth analysis. Consequently, it was elucidated that a fatty film adhered with hydrophilic groups faced to the oxidized surface and with hydrophobic groups faced to the outside, and that this adhered fatty acid also formed a metallic soap by a heat treatment, deteriorating the fattiness. Further, the paper also reports on the analysis of crystal structures on the surface layer with the use of GIXD (grazing incidence-angle X-ray diffraction). 22 refs., 15 figs.

  8. Study on the Surface Integrity of a Thin-Walled Aluminum Alloy Structure after a Bilateral Slid Rolling Process

    Directory of Open Access Journals (Sweden)

    Laixiao Lu

    2016-04-01

    Full Text Available For studying the influence of a bilateral slid rolling process (BSRP on the surface integrity of a thin-walled aluminum alloy structure, and revealing the generation mechanism of residual stresses, a self-designed BSRP appliance was used to conduct rolling experiments. With the aid of a surface optical profiler, an X-ray stress analyzer, and a scanning electron microscope (SEM, the differences in surface integrity before and after BSRP were explored. The internal changing mechanism of physical as well as mechanical properties was probed. The results show that surface roughness (Ra is reduced by 23.7%, microhardness is increased by 21.6%, and the depth of the hardening layer is about 100 μm. Serious plastic deformation was observed within the subsurface of the rolled region. The residual stress distributions along the depth of the rolling surface and milling surface were tested respectively. Residual stresses with deep and high amplitudes were generated via the BSRP. Based on the analysis of the microstructure, the generation mechanism of the residual stresses was probed. The residual stress of the rolling area consisted of two sections: microscopic stresses caused by local plastic deformation and macroscopic stresses caused by overall non-uniform deformation.

  9. The Effects of Different Electrode Types for Obtaining Surface Machining Shape on Shape Memory Alloy Using Electrochemical Machining

    Science.gov (United States)

    Choi, S. G.; Kim, S. H.; Choi, W. K.; Moon, G. C.; Lee, E. S.

    2017-06-01

    Shape memory alloy (SMA) is important material used for the medicine and aerospace industry due to its characteristics called the shape memory effect, which involves the recovery of deformed alloy to its original state through the application of temperature or stress. Consumers in modern society demand stability in parts. Electrochemical machining is one of the methods for obtained these stabilities in parts requirements. These parts of shape memory alloy require fine patterns in some applications. In order to machine a fine pattern, the electrochemical machining method is suitable. For precision electrochemical machining using different shape electrodes, the current density should be controlled precisely. And electrode shape is required for precise electrochemical machining. It is possible to obtain precise square holes on the SMA if the insulation layer controlled the unnecessary current between electrode and workpiece. If it is adjusting the unnecessary current to obtain the desired shape, it will be a great contribution to the medical industry and the aerospace industry. It is possible to process a desired shape to the shape memory alloy by micro controlling the unnecessary current. In case of the square electrode without insulation layer, it derives inexact square holes due to the unnecessary current. The results using the insulated electrode in only side show precise square holes. The removal rate improved in case of insulated electrode than others because insulation layer concentrate the applied current to the machining zone.

  10. Employing Ti nano-powder dielectric to enhance surface characteristics in electrical discharge machining of AISI D2 steel

    Energy Technology Data Exchange (ETDEWEB)

    Marashi, Houriyeh, E-mail: houriyeh@marashi.co [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Center of Advanced Manufacturing and Materials Processing (AMMP), 50603 Kuala Lumpur (Malaysia); Sarhan, Ahmed A.D., E-mail: ah_sarhan@yahoo.com [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Center of Advanced Manufacturing and Materials Processing (AMMP), 50603 Kuala Lumpur (Malaysia); Department of Mechanical Engineering, Faculty of Engineering, Assiut University, Assiut 71516 (Egypt); Hamdi, Mohd [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Center of Advanced Manufacturing and Materials Processing (AMMP), 50603 Kuala Lumpur (Malaysia)

    2015-12-01

    Graphical abstract: - Highlights: • We proposed adding Ti nano-powder to dielectric in EDM. • Average and peak-valley surface roughness was improved by 35 and 40%, respectively. • Improvement of up to 69% in material removal rate was obtained. • Enhanced surface morphology and formation of shallower craters were observed. - Abstract: Manufacturing components with superior surface characteristics is challenging when electrical discharge machining (EDM) is employed for mass production. The aim of this research is to enhance the characteristics of AISI D2 steel surface machined with EDM through adding Ti nano-powder to dielectric under various machining parameters, including discharge duration (T{sub on}) and peak current (I). Surface roughness profilometer, FESEM and AFM analysis were utilized to reveal the machined surface characteristics in terms of surface roughness, surface morphology and surface micro-defects. Moreover, EDX analysis was performed in order to evaluate the atomic deposition of Ti nano-powder on the surface. The concentration of Ti nano-powder in dielectric was also examined using ESEM and EDX. According to the results, the addition of Ti nano-powder to dielectric notably enhanced the surface morphology and surface roughness at all machining parameters except T{sub on} = 340 μs. Of these parameters, maximum enhancement was observed at T{sub on} = 210 μs, where the material removal rate and average surface roughness improved by ∼69 and ∼35% for peak current of 6 and 12 A, respectively. Elemental analysis signified negligible Ti deposition on the machined surface while the atomic concentration of Ti was increased around the crack areas.

  11. Analysis of Effects of Cutting Parameters of Wire Electrical Discharge Machining on Material Removal Rate and Surface Integrity

    International Nuclear Information System (INIS)

    Tonday, H. R.; Tigga, A. M.

    2016-01-01

    As wire electrical discharge machining is pioneered as a vigorous, efficient and precise and complex nontraditional machining technique, research is needed in this area for efficient machining. In this paper, the influence of various input factors of wire electrical discharge machining (WEDM) on output variable has been analyzed by using Taguchi technique and analysis of variance. The design of experiments has been done and by applying L8 orthogonal arrays method and experiments have been conducted and collected required data. The objectives of the research are to maximize the material removal rate and to minimize the surface roughness value (Ra). Surface morphology of machined workpiece has been obtained and examined by employing scanning electron microscopy (SEM) technique. (paper)

  12. Analysis of Effects of Cutting Parameters of Wire Electrical Discharge Machining on Material Removal Rate and Surface Integrity

    Science.gov (United States)

    Tonday, H. R.; Tigga, A. M.

    2016-02-01

    As wire electrical discharge machining is pioneered as a vigorous, efficient and precise and complex nontraditional machining technique, research is needed in this area for efficient machining. In this paper, the influence of various input factors of wire electrical discharge machining (WEDM) on output variable has been analyzed by using Taguchi technique and analysis of variance. The design of experiments has been done and by applying L8 orthogonal arrays method and experiments have been conducted and collected required data. The objectives of the research are to maximize the material removal rate and to minimize the surface roughness value (Ra). Surface morphology of machined workpiece has been obtained and examined by employing scanning electron microscopy (SEM) technique.

  13. The influence of cooling techniques on cutting forces and surface roughness during cryogenic machining of titanium alloys

    Directory of Open Access Journals (Sweden)

    Wstawska Iwona

    2016-12-01

    Full Text Available Titanium alloys are one of the materials extensively used in the aerospace industry due to its excellent properties of high specific strength and corrosion resistance. On the other hand, they also present problems wherein titanium alloys are extremely difficult materials to machine. In addition, the cost associated with titanium machining is also high due to lower cutting velocities and shorter tool life. The main objective of this work is a comparison of different cooling techniques during cryogenic machining of titanium alloys. The analysis revealed that applied cooling technique has a significant influence on cutting force and surface roughness (Ra parameter values. Furthermore, in all cases observed a positive influence of cryogenic machining on selected aspects after turning and milling of titanium alloys. This work can be also the starting point to the further research, related to the analysis of cutting forces and surface roughness during cryogenic machining of titanium alloys.

  14. Effect of processing conditions on residual stress distributions by bead-on-plate welding after surface machining

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Mochizuki, Masahito

    2014-01-01

    Residual stress is important factor for stress corrosion cracking (SCC) that has been observed near the welded zone in nuclear power plants. Especially, surface residual stress is significant for SCC initiation. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and residual stress distribution due to surface machining is varied by the subsequent butt welding. In previous paper, authors reported that residual stress distribution generated by bead on plate welding after surface machining has a local maximum residual stress near the weld metal. The local maximum residual stress shows approximately 900 MPa that exceeds the stress threshold for SCC initiation. Therefore, for the safety improvement of nuclear power plants, a study on the local maximum residual stress is important. In this study, the effect of surface machining and welding conditions on residual stress distribution generated by welding after surface machining was investigated. Surface machining using lathe machine and bead on plate welding with tungsten inert gas (TIG) arc under various conditions were conducted for plate specimens made of SUS316L. Then, residual stress distributions were measured by X-ray diffraction method (XRD). As a result, residual stress distributions have the local maximum residual stress near the weld metal in all specimens. The values of the local maximum residual stresses are almost the same. The location of the local maximum residual stress is varied by welding condition. It could be consider that the local maximum residual stress is generated by same generation mechanism as welding residual stress in surface machined layer that has high yield stress. (author)

  15. Effects of Surface Nitrification on Thermal Conductivity of Modified Aluminum Oxide Nanofibers-Reinforced Epoxy Matrix Nanocomposites

    International Nuclear Information System (INIS)

    Kim, Byungjoo; Bae, Kyongmin; An, Kayhyeok; Park, Soojin

    2012-01-01

    Aluminum oxide (Al 2 O 3 ) nanofibers were treated thermally under an ammonia (NH 3 ) gas stream balanced by nitrogen to form a thin aluminum nitride (AlN) layer on the nanofibers, resulting in the enhancement of thermal conductivity of Al 2 O 3 /epoxy nanocomposites. The micro-structural and morphological properties of the NH 3 -assisted thermally-treated Al 2 O 3 nanofibers were characterized by X-ray diffraction (XRD) and atomic force microscopy (AEM), respectively. The surface characteristics and pore structures were observed by X-ray photoelectron spectroscopy (XPS), Zeta-potential and N 2 /77 K isothermal adsorptions. From the results, the formation of AlN on Al 2 O 3 nanofibers was confirmed by XRD and XPS. The thermal conductivity (TC) of the modified Al 2 O 3 nanofibers/epoxy composites increased with increasing treated temperatures. On the other hand, the severely treated Al 2 O 3 /epoxy composites showed a decrease in TC, resulting from a decrease in the probability of heat-transfer networks between the filler and matrix in this system due to the aggregation of nanofiber fillers

  16. Interfacial Interaction in Anodic Aluminum Oxide Templates Modifies Morphology, Surface Area, and Crystallization of Polyamide-6 Nanofibers.

    Science.gov (United States)

    Xue, Junhui; Xu, Yizhuang; Jin, Zhaoxia

    2016-03-08

    Here, we demonstrated that, when the precipitation process of polyamide-6 (PA6) solution happens in cylindrical channels of an anodized aluminum oxide membrane (AAO), interface interactions between a solid surface, solvent, non-solvent, and PA6 will influence the obtained polymer nanostructures, resulting in complex morphologies, increased surface area, and crystallization changes. With the enhancing interaction of PA6 and the AAO surface, the morphology of PA6 nanostructures changes from solid nanofibers, mesoporous, to bamboo-like, while at the same time, metastable γ-phase domains increase in these PA6 nanostructures. Brunauer-Emmett-Teller (BET) surface areas of solid, bamboo-like, and mesoporous PA6 nanofibers rise from 16, 20.9, to 25 m(2)/g. This study shows that interfacial interaction in AAO template fabrication can be used in manipulating the morphology and crystallization of one-dimensional polymer nanostructures. It also provides us a simple and novel method to create porous PA6 nanofibers with a large surface area.

  17. Enhancing structural integrity of adhesive bonds through pulsed laser surface micro-machining

    KAUST Repository

    Diaz, Edwin Hernandez

    2015-06-01

    Enhancing the effective peel resistance of plastically deforming adhesive joints through laser-based surface micro-machining Edwin Hernandez Diaz Inspired by adhesion examples commonly found in nature, we reached out to examine the effect of different kinds of heterogeneous surface properties that may replicate this behavior and the mechanisms at work. In order to do this, we used pulsed laser ablation on copper substrates (CuZn40) aiming to increase adhesion for bonding. A Yb-fiber laser was used for surface preparation of the substrates, which were probed with a Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS). Heterogeneous surface properties were devised through the use of simplified laser micromachined patterns which may induce sequential events of crack arrest propagation, thereby having a leveraging effect on dissipation. The me- chanical performance of copper/epoxy joints with homogeneous and heterogeneous laser micromachined interfaces was then analyzed using the T-peel test. Fractured surfaces were analyzed using SEM to resolve the mechanism of failure and adhesive penetration within induced surface asperities from the treatment. Results confirm positive modifications of the surface morphology and chemistry from laser ablation that enable mechanical interlocking and cohesive failure within the adhesive layer. Remarkable improvements of apparent peel energy, bond toughness, and effective peel force were appreciated with respect to sanded substrates as control samples.

  18. Statistical analysis of surface roughness of machined graphite by means of CNC milling

    Directory of Open Access Journals (Sweden)

    Orquídea Sánchez López

    2016-09-01

    Full Text Available The aim of this research is to analyze the influence of cutting speed, feed rate and cutting depth on the surface finish of grade GSP-70 graphite specimens for use in electrical discharge machining (EDM for material removal by means of Computer Numerical Control (CNC milling with low-speed machining (LSM. A two-level factorial design for each of the three established factors was used for the statistical analysis. The analysis of variance (ANOVA indicates that cutting speed and feed rate are the two most significant factors with regard to the roughness obtained with grade GSP-70 graphite by means of CNC milling. A second order regression analysis was also conducted to estimate the roughness average (Ra in terms of the cutting speed, feed rate and cutting depth. Finally, the comparison between predicted roughness by means of a second order regression model and the roughness obtained by machined specimens considering the combinations of low and high levels of roughness is also presented.

  19. Exploring a potential energy surface by machine learning for characterizing atomic transport

    Science.gov (United States)

    Kanamori, Kenta; Toyoura, Kazuaki; Honda, Junya; Hattori, Kazuki; Seko, Atsuto; Karasuyama, Masayuki; Shitara, Kazuki; Shiga, Motoki; Kuwabara, Akihide; Takeuchi, Ichiro

    2018-03-01

    We propose a machine-learning method for evaluating the potential barrier governing atomic transport based on the preferential selection of dominant points for atomic transport. The proposed method generates numerous random samples of the entire potential energy surface (PES) from a probabilistic Gaussian process model of the PES, which enables defining the likelihood of the dominant points. The robustness and efficiency of the method are demonstrated on a dozen model cases for proton diffusion in oxides, in comparison with a conventional nudge elastic band method.

  20. Diagnostic measurements on the great machines conditions of lignite surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Helebrant, F.; Jurman, J.; Fries, J. [Technical University of Ostrava, Ostrava-Poruba (Czech Republic)

    2005-07-01

    An analysis of the diagnosis of loading and service dependability of a rail-mounted excavator used in surface lignite mining is described. Wheel power vibrations in electric motor bearings and electric motor input bearings to the gearbox were measured in situ, in horizontal, vertical, and axial directions. The data were analyzed using a mathematical relationship. The results are presented in a loading diagram that shows the deterioration and the acceptable lower bound of machine conditions over time. Work is continuing. 5 refs., 1 fig.

  1. MOUNTABILITY PARTS OF MACHINE WITH ROTATING SURFACE, FITTED WITH POSITIVE CLEARANCE

    Directory of Open Access Journals (Sweden)

    Zbigniew BUDNIAK

    2014-06-01

    Full Text Available In this paper demonstrates the conditions of automatic assembly the parts of machines with rotating surfaces, fitted with positive clearance. Determination of the general condition of asseblability allowed for designation of the acceptable relative displacement and torsion axle, combined parts on the mounting position. The designation of depending allowed for assess the technological capacity of the installation equipment. On the basis of this mathematical model was developed a computer program that allows to determine the effect of geometric, strength and dynamic parameters of the assembly process. The examples of results of numerical calculations are shown in the graphs

  2. Atomic force microscopy-based repeated machining theory for nanochannels on silicon oxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.Q., E-mail: wangzhiqian@sia.cn [State Key Laboratory of Robotics, Shenyang Institute of Automation, CAS, Shenyang 110016 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Jiao, N.D. [State Key Laboratory of Robotics, Shenyang Institute of Automation, CAS, Shenyang 110016 (China); Tung, S. [Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Dong, Z.L. [State Key Laboratory of Robotics, Shenyang Institute of Automation, CAS, Shenyang 110016 (China)

    2011-02-01

    The atomic force microscopy (AFM)-based repeated nanomachining of nanochannels on silicon oxide surfaces is investigated both theoretically and experimentally. The relationships of the initial nanochannel depth vs. final nanochannel depth at a normal force are systematically studied. Using the derived theory and simulation results, the final nanochannel depth can be predicted easily. Meanwhile, if a nanochannel with an expected depth needs to be machined, a right normal force can be selected simply and easily in order to decrease the wear of the AFM tip. The theoretical analysis and simulation results can be effectively used for AFM-based fabrication of nanochannels.

  3. A preliminary study of ester oxidation on an aluminum surface using chemiluminescence

    Science.gov (United States)

    Jones, William R., Jr.; Meador, Michael A.; Morales, Wilfredo

    1987-01-01

    The oxidation characteristics of a pure ester (trimethyolpropane triheptanoate) were studied by using a chemiluminescence technique. Tests were run in a thin-film micro-oxidation apparatus with an aluminum alloy catalyst. Conditions included a pure oxygen atmosphere and a temperature range of 176 to 206 C. Results indicated that oxidation of the ester (containing 10 to the minus 3rd power M diphenylanthracene as an intensifier) was accompanied by emission of light. The maximum intensity of light emission (I sub max) was a function of the amount of ester, the concentration of intensifier, and the test temperature. The induction period or the time to reach one-half of maximum intensity (t sub 1/2) was an inverse function of test temperature. Decreases in light emission at the later stages of a test were caused by depletion of the intensifier.

  4. Low-temperature aluminum reduction of graphene oxide, electrical properties, surface wettability, and energy storage applications.

    Science.gov (United States)

    Wan, Dongyun; Yang, Chongyin; Lin, Tianquan; Tang, Yufeng; Zhou, Mi; Zhong, Yajuan; Huang, Fuqiang; Lin, Jianhua

    2012-10-23

    Low-temperature aluminum (Al) reduction is first introduced to reduce graphene oxide (GO) at 100-200 °C in a two-zone furnace. The melted Al metal exhibits an excellent deoxygen ability to produce well-crystallized reduced graphene oxide (RGO) papers with a low O/C ratio of 0.058 (Al-RGO), compared with 0.201 in the thermally reduced one (T-RGO). The Al-RGO papers possess outstanding mechanical flexibility and extremely high electrical conductivities (sheet resistance R(s) ~ 1.75 Ω/sq), compared with 20.12 Ω/sq of T-RGO. More interestingly, very nice hydrophobic nature (90.5°) was observed, significantly superior to the reported chemically or thermally reduced papers. These enhanced properties are attributed to the low oxygen content in the RGO papers. During the aluminum reduction, highly active H atoms from H(2)O reacted with melted Al promise an efficient oxygen removal. This method was also applicable to reduce graphene oxide foams, which were used in the GO/SA (stearic acid) composite as a highly thermally conductive reservoir to hold the phase change material for thermal energy storage. The Al-reduced RGO/SnS(2) composites were further used in an anode material of lithium ion batteries possessing a higher specific capacity. Overall, low-temperature Al reduction is an effective method to prepare highly conductive RGO papers and related composites for flexible energy conversion and storage device applications.

  5. Machinability of Al 6061 Deposited with Cold Spray Additive Manufacturing

    Science.gov (United States)

    Aldwell, Barry; Kelly, Elaine; Wall, Ronan; Amaldi, Andrea; O'Donnell, Garret E.; Lupoi, Rocco

    2017-10-01

    Additive manufacturing techniques such as cold spray are translating from research laboratories into more mainstream high-end production systems. Similar to many additive processes, finishing still depends on removal processes. This research presents the results from investigations into aspects of the machinability of aluminum 6061 tubes manufactured with cold spray. Through the analysis of cutting forces and observations on chip formation and surface morphology, the effect of cutting speed, feed rate, and heat treatment was quantified, for both cold-sprayed and bulk aluminum 6061. High-speed video of chip formation shows changes in chip form for varying material and heat treatment, which is supported by the force data and quantitative imaging of the machined surface. The results shown in this paper demonstrate that parameters involved in cold spray directly impact on machinability and therefore have implications for machining parameters and strategy.

  6. Evaluation of Surface Roughness and Power Consumption in Machining FCD 450 Cast Iron using Coated and Uncoated Irregular Milling Tools

    International Nuclear Information System (INIS)

    Yusoff, Ahmad Razlan; Arsyad, Fitriyanti

    2016-01-01

    In this project, the effects of different cutting parameters on surface roughness and power consumption when machining FCD450 cast iron were studied using coated and uncoated irregular milling tool geometry of variable helix and pitch. Their responses on roughness and power consumption were evaluated based on the spindle speed, feed rate, and depth of cut, machining length and machining time. Results showed that except spindle speed and machining length, other parameters such as feed rate, axial and radial depth of cut and also machining time proportionate with surface roughness. The power consumption proportionately increase for all cutting parameters except feedrate. It is showed that the average decrement 27.92 percent for surface roughness and average decrement 9.32 percent for power consumption by using coated compared to uncoated tool. Optimum cutting parameters for both minimum surface roughness and power consumption can be determined. The coated tools performed better than uncoated milling tools for responses of surface roughness and power consumption to increase machining productivity and profit. (paper)

  7. In situ monitoring of thermal crystallization of ultrathin tris(8-hydroxyquinoline) aluminum films using surface-enhanced Raman scattering.

    Science.gov (United States)

    Muraki, Naoki

    2014-01-01

    Thermal crystallization of 3, 10, and 60 nm-thick tris(8-hydroxyquinoline)aluminum (Alq3) films is studied using surface-enhanced Raman scattering with a constant heating rate. An abrupt higher frequency shift of the quinoline-stretching mode is found to be an indication of a phase transition of Alq3 molecules from amorphous to crystalline. While the 60 nm-thick film shows the same crystallization temperature as a bulk sample, the thinner films were found to have a lower crystallization temperature and slower rate of crystallization. Non-isothermal kinetics analysis is performed to quantify kinetic properties such as the Avrami exponent constants and crystallization rates of ultrathin Alq3 films.

  8. Thermal-mechanical simulation of high-current pulsed electron beam surface modification process of pure aluminum

    International Nuclear Information System (INIS)

    Zou Jianxin; Qin Ying; Wu Aimin; Hao Shengzhi; Wang Xiaogang; Dong Chuang

    2004-01-01

    A mathematical physics model is established to describe the surface modification process of High Current Pulsed Electron Beams (HCPEB) of pure aluminum alloy. Computer simulation is used to reveal the phenomena of fast heating and cooling, melting, solidification, evaporation, and thermal stress wave associated with the HCPEB bombardment. The calculated melting depth is about 1-10 μm, which is close to the experimental results. The evaporated layer is at nanometer level, which can be omitted in the calculation of temperature field. The thermal stress wave, though as weak as about 0.1 MPa in peak amplitude (proportional to pulsed energy density), has strong impacts on material's structure and properties. (authors)

  9. Electrosynthesis of Polyaniline-TiO2 Nanocomposite Films on Aluminum Alloy 3004 Surface and its Corrosion Protection Performance

    Directory of Open Access Journals (Sweden)

    M. Shabani-Nooshabadi

    2013-03-01

    Full Text Available The direct synthesis of polyaniline-TiO2 nanocomposite coatings on aluminum alloy 3004 (AA3004 surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by FT-IR, SEM-EDX, SEM and AFM. Optical absorption spectroscopy reveals the formation of the emeraldine oxidation state form of polyaniline-TiO2 nanocomposite. The corrosion performances of polyaniline-TiO2 nanocomposite coatings were investigated in 3.5% NaCl solution by Tafel polarization and Electrochemical Impedance Spectroscopy (EIS methods. The corrosion rate of polyaniline-TiO2 nanocomposite coating on AA3004 was found ∼260 times lower than bare AA3004 and corrosion potentials of these coatings have shifted to more positive potentials (105 mV. The results of this study clearly ascertain that the polyaniline-TiO2 nanocomposite coating has outstanding potential to protect the AA3004 against corrosion in a chloride environment.

  10. The Interface Structure of High-Temperature Oxidation-Resistant Aluminum-Based Coatings on Titanium Billet Surface

    Science.gov (United States)

    Xu, Zhefeng; Rong, Ju; Yu, Xiaohua; Kun, Meng; Zhan, Zhaolin; Wang, Xiao; Zhang, Yannan

    2017-10-01

    A new type of high-temperature oxidation-resistant aluminum-based coating, on a titanium billet surface, was fabricated by the cold spray method, at a high temperature of 1050°C, for 8 h, under atmospheric pressure. The microstructure of the exposed surface was analyzed via optical microscopy, the microstructure of the coating and elemental diffusion was analyzed via field emission scanning electron microscopy, and the interfacial phases were identified via x-ray diffraction. The Ti-Al binary phase diagram and Gibbs free energy of the stable phase were calculated by Thermo-calc. The results revealed that good oxidation resistant 50-μm-thick coatings were successfully obtained after 8 h at 1050°C. Two layers were obtained after the coating process: an Al2O3 oxidation layer and a TiAl3 transition layer on the Ti-based substrate. The large and brittle Al2O3 grains on the surface, which can be easily spalled off from the surface after thermal processing, protected the substrate against oxidation during processing. In addition, the thermodynamic calculation results were in good agreement with the experimental data.

  11. EXPERIMENTAL INVESTIGATION OF THE EFFECT OF MACHINIG PARAMETERS OVER CUTTING FORCE AND SURFACE ROUGHNESS IN THE MACHINABILITY OF AA5052 ALLOY

    Directory of Open Access Journals (Sweden)

    Hasan GÖKKAYA

    2006-03-01

    Full Text Available In this study, the effects of different cutting and feed rates over average surface roughness and main cutting force during the machinability of AA5052 aluminum alloy with uncoated cemented carbide insert were evaluated. In the experiments, stable depth of cut (1.5 mm, four different cutting speeds (200, 300, 400, 500 m/min and five different feed rates (0.10, 0.15, 0.20, 0.25, 0.30 mm/rev were used. Based on cutting and feed rates, the lowest main cutting force was obtained as 113 in 500 m/min cutting speed and 0.10 mm/rev feed rate and the highest cutting force was obtained as 332 N in 200 m/min cutting speed and 0.30 mm/rev feed rate. The lowest average surface roughness was obtained as 0.95 µm in 200 m/min cutting speed and 0.10 mm/rev feed rate and the highest average surface roughness was obtained as 6.65 µm in 300 m/min cutting speed and 0.30 mm/rev feed rate.

  12. Deriving global parameter estimates for the Noah land surface model using FLUXNET and machine learning

    Science.gov (United States)

    Chaney, Nathaniel W.; Herman, Jonathan D.; Ek, Michael B.; Wood, Eric F.

    2016-11-01

    With their origins in numerical weather prediction and climate modeling, land surface models aim to accurately partition the surface energy balance. An overlooked challenge in these schemes is the role of model parameter uncertainty, particularly at unmonitored sites. This study provides global parameter estimates for the Noah land surface model using 85 eddy covariance sites in the global FLUXNET network. The at-site parameters are first calibrated using a Latin Hypercube-based ensemble of the most sensitive parameters, determined by the Sobol method, to be the minimum stomatal resistance (rs,min), the Zilitinkevich empirical constant (Czil), and the bare soil evaporation exponent (fxexp). Calibration leads to an increase in the mean Kling-Gupta Efficiency performance metric from 0.54 to 0.71. These calibrated parameter sets are then related to local environmental characteristics using the Extra-Trees machine learning algorithm. The fitted Extra-Trees model is used to map the optimal parameter sets over the globe at a 5 km spatial resolution. The leave-one-out cross validation of the mapped parameters using the Noah land surface model suggests that there is the potential to skillfully relate calibrated model parameter sets to local environmental characteristics. The results demonstrate the potential to use FLUXNET to tune the parameterizations of surface fluxes in land surface models and to provide improved parameter estimates over the globe.

  13. DETERMINATION OF OPTIMAL BALL BURNISHING PARAMETERS FOR SURFACE ROUGHNESS OF ALUMINUM ALLOY

    Directory of Open Access Journals (Sweden)

    D.B. Patel

    2013-06-01

    Full Text Available Burnishing is a cold-working process, which easily produces a smooth and work-hardened surface through the plastic deformation of surface irregularities. In the present work, the influences of the main burnishing parameters (speed, feed, force, number of tool passes, and ball diameter on the surface roughness are studied. It is found that the burnishing forces and the number of tool passes are the parameters that have the greatest effect on the workpiece surface during the burnishing process.

  14. Nanoscale surface potential imaging of the photocatalytic TiO2 films on aluminum

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Dirscherl, Kai; Canulescu, Stela

    2013-01-01

    in the surface potential of TiO2 coatings upon UV-illumination are closely correlated to the band gap and thickness of the coatings. The inhomogeneity surface potential distribution of a 100 nm TiO2 film indicates a heterogeneous coating. Transition to a homogeneous surface potential distribution was observed...

  15. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  16. Fourier decomposition of segmented magnets with radial magnetization in surface-mounted PM machines

    Science.gov (United States)

    Tiang, Tow Leong; Ishak, Dahaman; Lim, Chee Peng

    2017-11-01

    This paper presents a generic field model of radial magnetization (RM) pattern produced by multiple segmented magnets per rotor pole in surface-mounted permanent magnet (PM) machines. The magnetization vectors from either odd- or even-number of magnet blocks per pole are described. Fourier decomposition is first employed to derive the field model, and later integrated with the exact 2D analytical subdomain method to predict the magnetic field distributions and other motor global quantities. For the assessment purpose, a 12-slot/8-pole surface-mounted PM motor with two segmented magnets per pole is investigated by using the proposed field model. The electromagnetic performances of the PM machines are intensively predicted by the proposed magnet field model which include the magnetic field distributions, airgap flux density, phase back-EMF, cogging torque, and output torque during either open-circuit or on-load operating conditions. The analytical results are evaluated and compared with those obtained from both 2D and 3D finite element analyses (FEA) where an excellent agreement has been achieved.

  17. CORROSION AND SURFACE PROTECTION IN MACHINE MATERIALS FRICTION HAVE DIFFERENT SURFACE PAIRS EXPERIMENTAL INVESTIGATION OF FACTORS

    OpenAIRE

    Senai YALCINKAYA

    2017-01-01

    Friction force, normal force, linear change. The normal force varies with the loads on the friction object. In order to determine the friction force and the friction coefficient, the friction object and the friction speed are used. The experimental work was carried out in three stages. In the first stage, the effect of normal force on the friction force was studied. In the second step, the friction force of the friction surface area is influenced. The effect of the change of the s...

  18. Structural changes in surface layer of steel 08Kh18N10T during machining

    International Nuclear Information System (INIS)

    Palenik, J.; Vodarek, V.

    1989-01-01

    The results are reported of a study of the surface layer of steel 08Kh18N10T affected by machining. Structural changes were studied caused by finish turning and by additional roller burnishing. Multiple deformation bands were observed to occur under the given cutting conditions; they mainly consisted of deformation doublets and only in isolated cases of ε-martensite. The presence of α'-martensite was not shown in the specimen surface layer following finish turning. The deformation shear bands in the roller-burnished specimen consisted of both ε-martensite and of deformation doublets. The amount of ε-martensite in the structure was significantly higher than in the specimen worked by turning. Local presence of α'-martensite formations was observed inside the deformation bands. It thus follows that roller burnishing is unsuitable as part of the manufacture of components from steel 08Kh18N10T. (J.B.). 5 figs., 1 tab., 9 refs

  19. A real-time surface inspection system for precision steel balls based on machine vision

    Science.gov (United States)

    Chen, Yi-Ji; Tsai, Jhy-Cherng; Hsu, Ya-Chen

    2016-07-01

    Precision steel balls are one of the most fundament components for motion and power transmission parts and they are widely used in industrial machinery and the automotive industry. As precision balls are crucial for the quality of these products, there is an urgent need to develop a fast and robust system for inspecting defects of precision steel balls. In this paper, a real-time system for inspecting surface defects of precision steel balls is developed based on machine vision. The developed system integrates a dual-lighting system, an unfolding mechanism and inspection algorithms for real-time signal processing and defect detection. The developed system is tested under feeding speeds of 4 pcs s-1 with a detection rate of 99.94% and an error rate of 0.10%. The minimum detectable surface flaw area is 0.01 mm2, which meets the requirement for inspecting ISO grade 100 precision steel balls.

  20. Improving resistance welding of aluminum sheets by addition of metal powder

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al-Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    . The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA....... In such cases the best results are obtained with pure aluminum powder....

  1. Prediction of the wear and evolution of cutting tools in a carbide / titanium-aluminum-vanadium machining tribosystem by volumetric tool wear characterization and modeling

    Science.gov (United States)

    Kuttolamadom, Mathew Abraham

    The objective of this research work is to create a comprehensive microstructural wear mechanism-based predictive model of tool wear in the tungsten carbide / Ti-6Al-4V machining tribosystem, and to develop a new topology characterization method for worn cutting tools in order to validate the model predictions. This is accomplished by blending first principle wear mechanism models using a weighting scheme derived from scanning electron microscopy (SEM) imaging and energy dispersive x-ray spectroscopy (EDS) analysis of tools worn under different operational conditions. In addition, the topology of worn tools is characterized through scanning by white light interferometry (WLI), and then application of an algorithm to stitch and solidify data sets to calculate the volume of the tool worn away. The methodology was to first combine and weight dominant microstructural wear mechanism models, to be able to effectively predict the tool volume worn away. Then, by developing a new metrology method for accurately quantifying the bulk-3D wear, the model-predicted wear was validated against worn tool volumes obtained from corresponding machining experiments. On analyzing worn crater faces using SEM/EDS, adhesion was found dominant at lower surface speeds, while dissolution wear dominated with increasing speeds -- this is in conformance with the lower relative surface speed requirement for micro welds to form and rupture, essentially defining the mechanical load limit of the tool material. It also conforms to the known dominance of high temperature-controlled wear mechanisms with increasing surface speed, which is known to exponentially increase temperatures especially when machining Ti-6Al-4V due to its low thermal conductivity. Thus, straight tungsten carbide wear when machining Ti-6Al-4V is mechanically-driven at low surface speeds and thermally-driven at high surface speeds. Further, at high surface speeds, craters were formed due to carbon diffusing to the tool surface and

  2. Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

    Science.gov (United States)

    Xue, Maoqiang; Ling, Yisheng; Wu, Guisen; Liu, Xin; Ge, Dongtao; Shi, Wei

    2013-01-01

    Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Analysis of surface integrity in machining of AISI 304 stainless steel under various cooling and cutting conditions

    Science.gov (United States)

    Klocke, F.; Döbbeler, B.; Lung, S.; Seelbach, T.; Jawahir, I. S.

    2018-05-01

    Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers from low yield strength that limits its technological applications. In this paper, liquid nitrogen (LN2) as cryogenic coolant, as well as minimum quantity lubrication (MQL), was applied and investigated. As a reference, conventional flood cooling was examined. Besides the cooling conditions, the feed rate was varied in four steps. A large rounded cutting edge radius and finishing cutting parameters were chosen to increase the mechanical load on the machined surface. The surface integrity was evaluated at both, the microstructural and the topographical levels. After turning experiments, a detailed analysis of the microstructure was carried out including the imaging of the surface layer and hardness measurements at varying depths within the machined layer. Along with microstructural investigations, different topological aspects, e.g., the surface roughness, were analyzed. It was shown that the resulting microstructure strongly depends on the cooling condition. This study also shows that it was possible to increase the micro hardness in the top surface layer significantly.

  4. Fabrication of a superhydrophobic surface with fungus-cleaning properties on brazed aluminum for industrial application in heat exchangers

    Science.gov (United States)

    Lee, Jeong-Won; Hwang, Woonbong

    2018-06-01

    Extensive research has been carried out concerning the application of superhydrophobic coating in heat exchangers, but little is known about the application of this technique to brazed aluminum heat exchangers (BAHEs). In this work, we describe a new superhydrophobic coating method, which is suitable for BAHE use on an industrial scale. We first render the BAHE superhydrophobic by fabricating micro/nanostructures using solution dipping followed by fluorination. After the complete removal of the silicon residue, we verify using surface analysis that the BAHE surface is perfectly superhydrophobic. We also studied the fungus-cleaning properties of the superhydrophobic surface by growing fungus for 4 weeks in a moist environment on BAHE fins with and without superhydrophobic coating. We observed that, whereas the fungus grown on the untreated fins is extremely difficult to remove, the fungus on the fins with the superhydrophobic coating can be removed easily with only a modest amount of water. We also found that the coated BAHE fins exhibit excellent resistance to moisture. The superhydrophobic coating method that we propose is therefore expected to have a major impact in the heating, ventilating and air conditioning industry market.

  5. Conformation evolution of oil contaminants onto aluminum oxide surface in aqueous solution: The effect of surface coverage

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wenkun; Liu, Haitao, E-mail: xwk584523412@126.com; Sun, Yazhou; Fu, Hongya; Liang, Yingchun

    2017-01-15

    Highlights: • The dynamic conformational change of oil contaminations, at various surface coverages onto perfect α-Al{sub 2}O{sub 3}(0001) surface in aqueous solution is given. • The effect of surface coverage of oil molecules on the driving forces for the conformational change of oil contaminations is described. • The effect of interfacial water on the conformational change and even detachment of oil contaminations is considered. - Abstract: The microscopic conformational change process of oil contaminants adhered onto perfect α-Al{sub 2}O{sub 3} (0001) surface in aqueous solution was investigated by using all-atom classic molecular dynamics simulations. The change in removal mechanism of oil contaminants induced by surface coverage (surface area per molecule) was emphatically explored. Our simulation results strongly reveal that the increase in oil surface coverage induces an evident difference in microscopic detachment processes of oil contaminants. At a low surface coverage, oil contaminants can be thoroughly detached from solid surface. The whole detachment process could be divided into multi stages, including conformational change of oil contaminants on solid surface, dynamic motion of those in bulk solution and rapid migration of those from bulk solution to air/water interface. With surface coverage increasing, water diffusion becomes the key to induce conformational change and promote the detachment of oil contaminants. When oil surface coverage exceeds a threshold value, oil contaminants also undertake an evident conformational change process exhibiting typical characteristics but an incomplete detachment process occurs. All findings of the present study are helpful for the interpretation of the removal mechanism of oil contaminants on solid surface.

  6. Research on the method of improving the accuracy of CMM (coordinate measuring machine) testing aspheric surface

    Science.gov (United States)

    Cong, Wang; Xu, Lingdi; Li, Ang

    2017-10-01

    Large aspheric surface which have the deviation with spherical surface are being used widely in various of optical systems. Compared with spherical surface, Large aspheric surfaces have lots of advantages, such as improving image quality, correcting aberration, expanding field of view, increasing the effective distance and make the optical system compact, lightweight. Especially, with the rapid development of space optics, space sensor resolution is required higher and viewing angle is requred larger. Aspheric surface will become one of the essential components in the optical system. After finishing Aspheric coarse Grinding surface profile error is about Tens of microns[1].In order to achieve the final requirement of surface accuracy,the aspheric surface must be quickly modified, high precision testing is the basement of rapid convergence of the surface error . There many methods on aspheric surface detection[2], Geometric ray detection, hartmann detection, ronchi text, knifeedge method, direct profile test, interferometry, while all of them have their disadvantage[6]. In recent years the measure of the aspheric surface become one of the import factors which are restricting the aspheric surface processing development. A two meter caliber industrial CMM coordinate measuring machine is avaiable, but it has many drawbacks such as large detection error and low repeatability precision in the measurement of aspheric surface coarse grinding , which seriously affects the convergence efficiency during the aspherical mirror processing. To solve those problems, this paper presents an effective error control, calibration and removal method by calibration mirror position of the real-time monitoring and other effective means of error control, calibration and removal by probe correction and the measurement mode selection method to measure the point distribution program development. This method verified by real engineer examples, this method increases the original industrial

  7. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM

    Directory of Open Access Journals (Sweden)

    Ladeesh V. G.

    2017-01-01

    Full Text Available Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of machining parameters on surface roughness. Voltage, duty factor, frequency and tool feed rate are identified as the significant factors for controlling surface roughness of the channels produced by G-ECDM. A mathematical model was developed for surface roughness by considering the grinding action and thermal effects of electrochemical discharges in material removal. Experiments are conducted to validate the model and the results obtained are in good agreement with that predicted by the model.

  8. Oxidation of hydrogen-passivated silicon surfaces by scanning near-field optical lithography using uncoated and aluminum-coated fiber probes

    DEFF Research Database (Denmark)

    Madsen, Steen; Bozhevolnyi, Sergey I.; Birkelund, Karen

    1997-01-01

    Optically induced oxidation of hydrogen-passivated silicon surfaces using a scanning near-field optical microscope was achieved with both uncoated and aluminum-coated fiber probes. Line scans on amorphous silicon using uncoated fiber probes display a three-peak profile after etching in potassium...... hydroxide. Numerical simulations of the electromagnetic field around the probe-sample interaction region are used to explain the experimental observations. With an aluminum-coated fiber probe, lines of 35 nm in width were transferred into the amorphous silicon layer. (C) 1997 American Institute of Physics....

  9. On the evolution of surface roughness during deformation of polycrystalline aluminum alloys

    NARCIS (Netherlands)

    Vellinga, WP; van Tijum, Redmer; de Hosson, JTM

    Surface roughening of polycrystalline Al-Mg alloys during tensile deformation is investigated using white light confocal microscopy. Materials are tested that differ only in grain size. A height-height correlation technique is used to analyze the data. The surface obeys self-affine scaling on length

  10. Optimization of Surface Roughness and Wall Thickness in Dieless Incremental Forming Of Aluminum Sheet Using Taguchi

    Science.gov (United States)

    Hamedon, Zamzuri; Kuang, Shea Cheng; Jaafar, Hasnulhadi; Azhari, Azmir

    2018-03-01

    Incremental sheet forming is a versatile sheet metal forming process where a sheet metal is formed into its final shape by a series of localized deformation without a specialised die. However, it still has many shortcomings that need to be overcome such as geometric accuracy, surface roughness, formability, forming speed, and so on. This project focus on minimising the surface roughness of aluminium sheet and improving its thickness uniformity in incremental sheet forming via optimisation of wall angle, feed rate, and step size. Besides, the effect of wall angle, feed rate, and step size to the surface roughness and thickness uniformity of aluminium sheet was investigated in this project. From the results, it was observed that surface roughness and thickness uniformity were inversely varied due to the formation of surface waviness. Increase in feed rate and decrease in step size will produce a lower surface roughness, while uniform thickness reduction was obtained by reducing the wall angle and step size. By using Taguchi analysis, the optimum parameters for minimum surface roughness and uniform thickness reduction of aluminium sheet were determined. The finding of this project helps to reduce the time in optimising the surface roughness and thickness uniformity in incremental sheet forming.

  11. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Directory of Open Access Journals (Sweden)

    Thangam Chinnadurai

    2016-12-01

    Full Text Available This study focuses on investigating the effects of process parameters, namely, Peak current (Ip, Pulse on time (Ton, Pulse off time (Toff, Water pressure (Wp, Wire feed rate (Wf, Wire tension (Wt, Servo voltage (Sv and Servo feed setting (Sfs, on the Material Removal Rate (MRR and Surface Roughness (SR for Wire electrical discharge machining (Wire-EDM of nickel using Taguchi method. Response Surface Methodology (RSM is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used.

  12. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    International Nuclear Information System (INIS)

    Chinnadurai, T.; Vendan, S.A.

    2016-01-01

    This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used. (Author)

  13. Prediction of material removal rate and surface roughness for wire electrical discharge machining of nickel using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Chinnadurai, T.; Vendan, S.A.

    2016-07-01

    This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used. (Author)

  14. An easy and environmentally-friendly approach to superamphiphobicity of aluminum surfaces

    Science.gov (United States)

    Deng, R.; Hu, Y. M.; Wang, L.; Li, Zh. H.; Shen, T.; Zhu, Y.; Xiang, J. Zh.

    2017-04-01

    Superamphiphobic Al surfaces were achieved via an easy and environmentally-friendly approach. Aqueous mixed solution of 0.7 M CuSO4 and 1 M NaCl was used to etch polished Al surfaces to fabricate a rough morphology distributed with microscale step-like pits. The uniformly distributed nanoscale petals covered on the microscale pits were obtained by subsequent 96 °C hot deionized water bathing for 13 min. Thus, the hierarchical micro/nanometer scale roughness was formed which provided the structural basic of superamphiphobic Al surfaces. By 1H, 1H, 2H, 2H-Perfluorodecyl-triethoxysilane (PFDTS) derivatization, desirable superamphiphobic Al surfaces were achieved with the highest static contact angles of 162° for water, 156° for peanut oil, respectively. Meanwhile, the sliding angles were lower than 10° for both water and peanut oil droplets. The as-prepared Al surfaces were investigated by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and optical contact angle measurements. The FE-SEM images of as-prepared Al surfaces showed a hierarchical micro/nanometer scale morphology. XPS analyses demonstrated the PFDTS derivitization on Al surfaces. The superamphiphobic Al surfaces presented good mechanical durability and chemical stability which have a wide range of applications in fields such as self-cleaning, anti-icing, anti-corrosion, oil transportation, energy harvesting, microfluidics, and so forth. The approach reported in this paper may easily realize the industrial production of superamphiphobic Al surfaces owing to the advantage of facile, low cost and environmentally-friendly.

  15. Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap

    International Nuclear Information System (INIS)

    Sun, Zhen-Qi; Huang, Ming-Hui; Hu, Guo-Huai

    2012-01-01

    Highlights: ► A new generation aluminum lithium alloy which special made for Chinese commercial plane was investigated. ► Pattern of aluminum lithium alloy and Ti alloy were shown after anodization. ► Crack propagation of samples bonded with different wide Ti straps were studied in this paper. -- Abstract: Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400 mm × 140 mm × 2 mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200 mm × 20 (40) mm × 2 mm was anodized in alkali solution. Patterns of two alloys were studied at original/anodized condition. And then, aluminum alloy and Ti alloy plates were assembled into a sample with FM 94 film adhesive. Fatigue crack behaviors of the sample were investigated under condition of nominal stress σ = 36 MPa and 54 MPa, stress ratio of 0.1. Testing results show that anodization treatment modifies alloys surface topography. Ti alloy bonding to Al–Li alloy plate effectively retards crack growth than that of Al–Li alloy plate. Fatigue life of sample bonded with Ti alloy strap improves about 62.5% than that of non-strap plate.

  16. The Effect Of Two-Stage Age Hardening Treatment Combined With Shot Peening On Stress Distribution In The Surface Layer Of 7075 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Kaczmarek Ł.

    2015-09-01

    Full Text Available The article present the results of the study on the improvement of mechanical properties of the surface layer of 7075 aluminum alloy via two-stage aging combined with shot peening. The experiments proved that thermo-mechanical treatment may significantly improve hardness and stress distribution in the surface layer. Compressive stresses of 226 MPa±5.5 MPa and hardness of 210±2 HV were obtained for selected samples.

  17. Corrosion Protection of Aluminum

    Science.gov (United States)

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  18. Exploring Machine Learning to Correct Satellite-Derived Sea Surface Temperatures

    Directory of Open Access Journals (Sweden)

    Stéphane Saux Picart

    2018-02-01

    Full Text Available Machine learning techniques are attractive tools to establish statistical models with a high degree of non linearity. They require a large amount of data to be trained and are therefore particularly suited to analysing remote sensing data. This work is an attempt at using advanced statistical methods of machine learning to predict the bias between Sea Surface Temperature (SST derived from infrared remote sensing and ground “truth” from drifting buoy measurements. A large dataset of collocation between satellite SST and in situ SST is explored. Four regression models are used: Simple multi-linear regression, Least Square Shrinkage and Selection Operator (LASSO, Generalised Additive Model (GAM and random forest. In the case of geostationary satellites for which a large number of collocations is available, results show that the random forest model is the best model to predict the systematic errors and it is computationally fast, making it a good candidate for operational processing. It is able to explain nearly 31% of the total variance of the bias (in comparison to about 24% for the multi-linear regression model.

  19. Nature and structure of aluminum surface sites grafted on silica from a combination of high-field aluminum-27 solid-state NMR spectroscopy and first-principles calculations

    KAUST Repository

    Kerber, Rachel Nathaniel; Kermagoret, Anthony; Callens, Emmanuel; Florian, Pierre A.; Massiot, Dominique; Lesage, Anne; Copé ret, Christophe; Delbecq, Franç oise; Rozanska, Xavier; Sautet, Philippe

    2012-01-01

    The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted with alkylaluminum compounds, a system typically studied as a model for a supported methylaluminoxane and aluminum cocatalyst. While 27Al solid-state NMR spectroscopy would be a method of choice, it has been difficult to apply this technique because of large quadrupolar broadenings. Here, from a combined use of the highest stable field NMR instruments (17.6, 20.0, and 23.5 T) and ultrafast magic angle spinning (>60 kHz), high-quality spectra were obtained, allowing isotropic chemical shifts, quadrupolar couplings, and asymmetric parameters to be extracted. Combined with first-principles calculations, these NMR signatures were then assigned to actual structures of surface aluminum sites. For silica (here SBA-15) reacted with triethylaluminum, the surface sites are in fact mainly dinuclear Al species, grafted on the silica surface via either two terminal or two bridging siloxy ligands. Tetrahedral sites, resulting from the incorporation of Al inside the silica matrix, are also seen as minor species. No evidence for putative tri-coordinated Al atoms has been found. © 2012 American Chemical Society.

  20. Nature and structure of aluminum surface sites grafted on silica from a combination of high-field aluminum-27 solid-state NMR spectroscopy and first-principles calculations

    KAUST Repository

    Kerber, Rachel Nathaniel

    2012-04-18

    The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted with alkylaluminum compounds, a system typically studied as a model for a supported methylaluminoxane and aluminum cocatalyst. While 27Al solid-state NMR spectroscopy would be a method of choice, it has been difficult to apply this technique because of large quadrupolar broadenings. Here, from a combined use of the highest stable field NMR instruments (17.6, 20.0, and 23.5 T) and ultrafast magic angle spinning (>60 kHz), high-quality spectra were obtained, allowing isotropic chemical shifts, quadrupolar couplings, and asymmetric parameters to be extracted. Combined with first-principles calculations, these NMR signatures were then assigned to actual structures of surface aluminum sites. For silica (here SBA-15) reacted with triethylaluminum, the surface sites are in fact mainly dinuclear Al species, grafted on the silica surface via either two terminal or two bridging siloxy ligands. Tetrahedral sites, resulting from the incorporation of Al inside the silica matrix, are also seen as minor species. No evidence for putative tri-coordinated Al atoms has been found. © 2012 American Chemical Society.

  1. Record high efficiency of screen-printed silicon aluminum back surface field solar cell: 20.29%

    Science.gov (United States)

    Kim, Ki Hyung; Park, Chang Sub; Doo Lee, Jae; Youb Lim, Jong; Yeon, Je Min; Kim, Il Hwan; Lee, Eun Joo; Cho, Young Hyun

    2017-08-01

    We have achieved a record high cell efficiency of 20.29% for an industrial 6-in. p-type monocrystalline silicon solar cell with a full-area aluminum back surface field (Al-BSF) by simply modifying the cell structure and optimizing the process with the existing cell production line. The cell efficiency was independently confirmed by the Solar Energy Research Institute of Singapore (SERIS). To increase the cell efficiency, for example, in four busbars, double printing, a lightly doped emitter with a sheet resistance of 90 to 100 Ω/□, and front surface passivation by using silicon oxynitride (SiON) on top of a silicon nitride (SiN x ) antireflection layer were adopted. To optimize front side processing, PC1D simulation was carried out prior to cell fabrication. The resulting efficiency gain is 0.64% compared with that in the reference cells with three busbars, a single antireflection coating layer, and a low-sheet-resistance emitter.

  2. The effect of laser surface melting on microstructure and corrosion behavior of friction stir welded aluminum alloy 2219

    Science.gov (United States)

    Ma, Shengchong; Zhao, Yong; Zou, Jiasheng; Yan, Keng; Liu, Chuan

    2017-11-01

    This study aimed to explore the electrochemical properties and microstructure of friction stir welds to understand the correlation between their properties and processing. Friction stir welding is a promising solid-state joining process for high-strength aluminum alloys (AA). Although friction stir welding (FSW) eliminates the problems of fusion welding due to the fact that it is performed below Tm, it causes severe plastic deformation in the material. Some AA welded by FSW exhibit relatively poor corrosion resistance. In this research, the corrosion resistance of such welds was enhanced through laser surface melting. A friction stir weld of AA 2219 was laser melted. The melt depth and microstructure were observed using optical and scanning electron microscopy. The melt zone exhibited epitaxially grown columnar grains. The redistribution of elemental composition was analyzed using energy-dispersive spectroscopy. The anticorrosion properties of both laser-melted and original welds were studied in aqueous 3.5% NaCl solution using cyclic potentiodynamic polarization. The results indicated a noticeable increase in the pitting corrosion resistance after the laser treatment on the surface. The repassivation potential was nobler than the corrosion potential after the laser treatment, confirming that the resistance to pitting growth improved.

  3. The microstructure of the surface layer of magnesium laser alloyed with aluminum and silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dziadoń, Andrzej [Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, Al. Tysiąclecia P.P. 7, 25-314 Kielce (Poland); Mola, Renata, E-mail: rmola@tu.kielce.pl [Faculty of Mechatronics and Mechanical Engineering, Kielce University of Technology, Al. Tysiąclecia P.P. 7, 25-314 Kielce (Poland); Błaż, Ludwik [Department of Structure and Mechanics of Solids, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków (Poland)

    2016-08-15

    The surface layer under analysis was formed as a result of diffusion bonding of a thin AlSi20 plate to a magnesium substrate followed by laser melting. Depending on the process parameters, the laser beam melted the AlSi20 plate only or the AlSi20 plate and a layer of the magnesium surface adjacent to it. Two types of microstructure of the remelted layer were thus analyzed. If the melting zone was limited to the AlSi20 plate, the microstructure of the surface layer was typical of a rapidly solidified hypereutectic Al–Si alloy. Since, however, the liquid AlSi20 reacted with the magnesium substrate, the following intermetallic phases formed: Al{sub 3}Mg{sub 2}, Mg{sub 17}Al{sub 12} and Mg{sub 2}Si. The microstructure of the modified surface layer of magnesium was examined using optical, scanning electron and transmission electron microscopy. The analysis of the surface properties of the laser modified magnesium revealed that the thin layer has a microstructure of a rapidly solidified Al–Si alloy offering good protection against corrosion. By contrast, the surface layer containing particles of intermetallic phases was more resistant to abrasion but had lower corrosion resistance than the silumin type layer. - Highlights: •A CO{sub 2} laser was used for surface alloying of Mg with AlSi20. •Before alloying, an AlSi20 plate was diffusion bonded with the Mg substrate. •The process parameters affected the alloyed layer microstructure and properties. •With melting limited to AlSi20, the layer had a structure of rapidly solidified AlSi20. •Mg–Al and Mg–Si phases were present when both the substrate and the plate were melted.

  4. The microstructure of the surface layer of magnesium laser alloyed with aluminum and silicon

    International Nuclear Information System (INIS)

    Dziadoń, Andrzej; Mola, Renata; Błaż, Ludwik

    2016-01-01

    The surface layer under analysis was formed as a result of diffusion bonding of a thin AlSi20 plate to a magnesium substrate followed by laser melting. Depending on the process parameters, the laser beam melted the AlSi20 plate only or the AlSi20 plate and a layer of the magnesium surface adjacent to it. Two types of microstructure of the remelted layer were thus analyzed. If the melting zone was limited to the AlSi20 plate, the microstructure of the surface layer was typical of a rapidly solidified hypereutectic Al–Si alloy. Since, however, the liquid AlSi20 reacted with the magnesium substrate, the following intermetallic phases formed: Al 3 Mg 2 , Mg 17 Al 12 and Mg 2 Si. The microstructure of the modified surface layer of magnesium was examined using optical, scanning electron and transmission electron microscopy. The analysis of the surface properties of the laser modified magnesium revealed that the thin layer has a microstructure of a rapidly solidified Al–Si alloy offering good protection against corrosion. By contrast, the surface layer containing particles of intermetallic phases was more resistant to abrasion but had lower corrosion resistance than the silumin type layer. - Highlights: •A CO 2 laser was used for surface alloying of Mg with AlSi20. •Before alloying, an AlSi20 plate was diffusion bonded with the Mg substrate. •The process parameters affected the alloyed layer microstructure and properties. •With melting limited to AlSi20, the layer had a structure of rapidly solidified AlSi20. •Mg–Al and Mg–Si phases were present when both the substrate and the plate were melted.

  5. Influence of Hydrostatic Pressure on the Corrosion Behavior of Superhydrophobic Surfaces on Bare and Oxidized Aluminum Substrates.

    Science.gov (United States)

    Ou, J F; Fang, X Z; Zhao, W J; Lei, S; Xue, M S; Wang, F J; Li, C Q; Lu, Y L; Li, W

    2018-05-22

    It is generally recognized that superhydrophobic surfaces in water may be used for corrosion resistance due to the entrapped air in the solid/liquid interface and could find potential applications in the protection of ship hull. For a superhydrophobic surface, as its immersion depth into water increases, the resultant hydrostatic pressure is also increased, and the entrapped air can be squeezed out much more easily. It is therefore predicted that high hydrostatic pressure would cause an unexpected decrease in corrosion resistance for the vessels in deep water (e.g., submarines) because of the unstable entrapped air. In this work, in order to clarify the role of hydrostatic pressure in the corrosion behavior of superhydrophobic surfaces, two typical superhydrophobic surfaces (SHSs) were prepared on bare and oxidized aluminum substrates, respectively, and then were immersed into the NaCl aqueous solutions with different depths of ∼0 cm (hydrostatic pressure ∼0 kPa), 10 cm (1 kPa), and 150 cm (15 kPa). It was found out for the SHSs on the oxidized Al, as the hydrostatic pressure increased, the corrosion behavior became severe. However, for the SHSs on the bare Al, their corrosion behavior was complex due to hydrostatic pressure. It was found that the corrosion resistance under 1 kPa was the highest. Further mechanism analysis revealed that this alleviated corrosion behavior under 1 kPa resulted from suppressing the oxygen diffusion through the liquid and reducing the subsequent corrosion rate as compared with 0 kPa, whereas the relatively low hydrostatic pressure (HP) could stabilize the entrapped air and hence enhance the corrosion resistance, compared with 15 kPa. The present study therefore provided a fundamental understanding for the applications of SHSs to prevent the corrosion, especially for various vessels in deep water.

  6. Investigation of surface roughness in micro-electro discharge machining of nonconductive ZrO2 for MEMS application

    International Nuclear Information System (INIS)

    Sabur, A; Moudood, A; Ali, M Y; Maleque, M A

    2013-01-01

    Micro-electro discharge machining technique, a noncontact machining process, is applied for drilling blind hole on nonconductive ZrO 2 ceramic for MEMS application. A conductive layer of adhesive copper is applied on the workpiece surface to initiate the sparks. Kerosene is used as dielectric for creation of continuous conductive pyrolytic carbon layer on the machined surface. Experiments are conducted by varying the voltage (V), capacitance (C) and rotational speed (N). Correlating these variables a mathematical model for surface roughness (SR) is developed using Taguchi method. The results showed that the V and C are the significant parameters of SR in micro-EDM for nonconductive ZrO 2 ceramic. The model also showed that SR increases with the increase of V and C

  7. Weldability, machinability and surfacing of commercial duplex stainless steel AISI2205 for marine applications – A recent review

    Directory of Open Access Journals (Sweden)

    A. Vinoth Jebaraj

    2017-05-01

    Full Text Available In the present review, attempts have been made to analyze the metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing. In the first part, effects of various fusion and solid-state welding processes on joining DSS 2205 with similar and dissimilar metals are addressed. Microstructural changes during the weld cooling cycle such as austenite reformation, partitioning of alloying elements, HAZ transformations, and the intermetallic precipitations are analyzed and compared with the different welding techniques. In the second part, machinability of DSS 2205 is compared with the commercial ASS grades in order to justify the quality of machining. In the third part, the importance of surface quality in a marine exposure is emphasized and the enhancement of surface properties through peening techniques is highlighted. The research gaps and inferences highlighted in this review will be more useful for the fabrications involved in the marine applications.

  8. Weldability, machinability and surfacing of commercial duplex stainless steel AISI2205 for marine applications - A recent review.

    Science.gov (United States)

    Vinoth Jebaraj, A; Ajaykumar, L; Deepak, C R; Aditya, K V V

    2017-05-01

    In the present review, attempts have been made to analyze the metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing. In the first part, effects of various fusion and solid-state welding processes on joining DSS 2205 with similar and dissimilar metals are addressed. Microstructural changes during the weld cooling cycle such as austenite reformation, partitioning of alloying elements, HAZ transformations, and the intermetallic precipitations are analyzed and compared with the different welding techniques. In the second part, machinability of DSS 2205 is compared with the commercial ASS grades in order to justify the quality of machining. In the third part, the importance of surface quality in a marine exposure is emphasized and the enhancement of surface properties through peening techniques is highlighted. The research gaps and inferences highlighted in this review will be more useful for the fabrications involved in the marine applications.

  9. Experimental investigation of surface quality in ultrasonic machining of WC-Co composites through Taguchi method

    Directory of Open Access Journals (Sweden)

    B. S. Pabla

    2016-08-01

    Full Text Available In manufacturing industries, the demand of WC-Co composite is flourishing because of the distinctive characteristics it offers such as: toughness (with hardness, good dimensional stability, higher mechanical strength etc. However, the difficulties in its machining restrict the application and competitiveness of this material. The current article has been targeted at evaluation of the effect of process conditions (varying power rating, cobalt content, tool material, part thickness, tool geometry, and size of abrasive particle on surface roughness in ultrasonic drilling of WC-Co composite. Results showed that abrasive grit size is most influential factor. From the microstructure analysis, the mode of material deformation has been observed and the parameters, i.e. work material properties, grit size, and power rating was revealed as the most crucial for the deformation mode.

  10. Effects of thickness and surface roughness on mechanical properties of aluminum sheets

    International Nuclear Information System (INIS)

    Suh, Chang Hee; Jung, Yun Chul; Kim, Young Suk

    2010-01-01

    The effect of thickness on the mechanical properties of Al 6K21-T4 sheet specimens under uniaxial tension was investigated. In order to reduce the thickness of the specimens without changing the microstructure and grain size, chemical etching was carried out, resulting in Al sheets ranging from 0.40 mm to 1.58 mm in thickness. Additionally, the effect of surface roughness was determined by finite element (FE) calculations performed using FE code MARC 2007. Tensile specimens of varying surface roughness were modeled and simulated. An analysis of the combined effects of the thickness and surface roughness revealed that the yield and tensile strengths decreased when the number of grains over the thickness was decreased. The ductility also decreased when reducing the thickness. An FE simulation showed that both the surface roughness and thickness affected the flow-curve shape. Moreover, the effect of the surface roughness tended to increase when decreasing the sheet thickness of specimens having the same roughness

  11. Study of Internal Channel Surface Roughnesses Manufactured by Selective Laser Melting in Aluminum and Titanium Alloys

    Science.gov (United States)

    Pakkanen, Jukka; Calignano, Flaviana; Trevisan, Francesco; Lorusso, Massimo; Ambrosio, Elisa Paola; Manfredi, Diego; Fino, Paolo

    2016-08-01

    Interest in additive manufacturing (AM) has gained considerable impetus over the past decade. One of the driving factors for AM success is the ability to create unique designs with intrinsic characteristics as, e.g., internal channels used for hydraulic components, cooling channels, and heat exchangers. However, a couple of the main problems in internal channels manufactured by AM technologies are the high surface roughness obtained and the distortion of the channel shape. There is still much to understand in these design aspects. In this study, a cylindrical geometry for internal channels to be built with different angles with respect to the building plane in AlSi10Mg and Ti6Al4V alloys by selective laser melting was considered. The internal surfaces of the channels produced in both materials were analyzed by means of a surface roughness tester and by optical and electron microscopy to evaluate the effects of the material and design choices.

  12. The ALU+ concept: n-type silicon solar cells with surface passivated screen-printed aluminum-alloyed rear emitter

    NARCIS (Netherlands)

    Bock, R.; Schmidt, J.; Mau, S.; Hoex, B.; Kessels, W.M.M.; Brendel, R.

    2009-01-01

    Aluminum-doped p-type (Al-p+) silicon emitters fabricated by means of screen-printing and firing are effectively passivated by plasma-enhanced chemicalvapor deposited (PECVD) amorphous silicon (a-Si) and atomic-layer-deposited (ALD) aluminum oxide (Al2O3) as well as Al2O3/SiNx stacks, where the

  13. Study on Surface Integrity of AISI 1045 Carbon Steel when machined by Carbide Cutting Tool under wet conditions

    Directory of Open Access Journals (Sweden)

    Tamin N. Fauzi

    2017-01-01

    Full Text Available This paper presents the evaluation of surface roughness and roughness profiles when machining carbon steel under wet conditions with low and high cutting speeds. The workpiece materials and cutting tools selected in this research were AISI 1045 carbon steel and canela carbide inserts graded PM25, respectively. The cutting tools undergo machining tests by CNC turning operations and their performances were evaluated by their surface roughness value and observation of the surface roughness profile. The machining tests were held at varied cutting speeds of 35 to 53 m/min, feed rate of 0.15 to 0.50 mm/rev and a constant depth of cut of 1 mm. From the analysis, it was found that surface roughness increased as the feed rate increased. Varian of surface roughness was suspected due to interaction between cutting speeds and feed rates as well as nose radius conditions; whether from tool wear or the formation of a built-up edge. This study helps us understand the effect of cutting speed and feed rate on surface integrity, when machining AISI 1045 carbon steel using carbide cutting tools, under wet cutting conditions.

  14. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores

  15. Control and Prevention of Ice Formation on the Surface of an Aluminum Alloy

    DEFF Research Database (Denmark)

    Rahimi, Maral

    modified with (3-aminopropyl) triethoxy silane (APTES) exhibited longer freezing delays as compared to both more hydrophilic and more hydrophobic substrates. This is attributed to a particular surface chemistry of the APTES modification that prevents ice formation at the interface of the substrate due...

  16. Characterizing water-metal interfaces and machine learning potential energy surfaces

    Science.gov (United States)

    Ryczko, Kevin

    In this thesis, we first discuss the fundamentals of ab initio electronic structure theory and density functional theory (DFT). We also discuss statistics related to computing thermodynamic averages of molecular dynamics (MD). We then use this theory to analyze and compare the structural, dynamical, and electronic properties of liquid water next to prototypical metals including platinum, graphite, and graphene. Our results are built on Born-Oppenheimer molecular dynamics (BOMD) generated using density functional theory (DFT) which explicitly include van der Waals (vdW) interactions within a first principles approach. All calculations reported use large simulation cells, allowing for an accurate treatment of the water-electrode interfaces. We have included vdW interactions through the use of the optB86b-vdW exchange correlation functional. Comparisons with the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional are also shown. We find an initial peak, due to chemisorption, in the density profile of the liquid water-Pt interface not seen in the liquid water-graphite interface, liquid watergraphene interface, nor interfaces studied previously. To further investigate this chemisorption peak, we also report differences in the electronic structure of single water molecules on both Pt and graphite surfaces. We find that a covalent bond forms between the single water molecule and the platinum surface, but not between the single water molecule and the graphite surface. We also discuss the effects that defects and dopants in the graphite and graphene surfaces have on the structure and dynamics of liquid water. Lastly, we introduce artificial neural networks (ANNs), and demonstrate how they can be used to machine learn electronic structure calculations. As a proof of principle, we show the success of an ANN potential energy surfaces for a dimer molecule with a Lennard-Jones potential.

  17. Some regularities of structure and surface layer properties changing of metal materials after electro-erosion machining

    International Nuclear Information System (INIS)

    Khvostyntsev, K.I.; Kuz'mina, T.S.; Kruglov, V.V.; Lukovkin, G.F.

    1982-01-01

    Effect of electoerosion machining on the surface state of pearlitic class steel of the 12KhN4MFA type, bronzes BrAMts 9-2 and BrAZhNMts 9-4-4-1, of the alloy PT-3V has been studied. As a result of electroerosion machining (EEM) a transformed layer, presenting overheated and partially melted metal, the structure and hardness of which depend on chemical composition of the materials treated, their tendency to phase transformatins and saturation with introduction elements, is formed on the surface of metal materials

  18. Some regularities of structure and surface layer properties changing of metal materials after electro-erosion machining

    Energy Technology Data Exchange (ETDEWEB)

    Khvostyntsev, K.I.; Kuz' mina, T.S.; Kruglov, V.V.; Lukovkin, G.F.

    1982-01-01

    Effect of electoerosion machining on the surface state of pearlitic class steel of the 12KhN4MFA type, bronzes BrAMts 9-2 and BrAZhNMts 9-4-4-1, of the alloy PT-3V has been studied. As a result of electroerosion machining (EEM) a transformed layer, presenting overheated and partially melted metal, the structure and hardness of which depend on chemical composition of the materials treated, their tendency to phase transformatins and saturation with introduction elements, is formed on the surface of metal materials.

  19. Aluminum Hydroxide

    Science.gov (United States)

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  20. CONDITIONS FOR STABLE CHIP BREAKING AND PROVISION OF MACHINED SURFACE QUALITY WHILE TURNING WITH ASYMMETRIC TOOL VIBRATIONS

    Directory of Open Access Journals (Sweden)

    V. K. Sheleh

    2015-01-01

    Full Text Available The paper considers a process of turning structural steel with asymmetric tool vibrations directed along feeding. Asymmetric vibrations characterized by asymmetry coefficient of vibration cycle, their frequency and amplitude are additionally transferred to the tool in the turning process with the purpose to crush chips. Conditions of stable chip breaking and obtaining optimum dimensions of chip elements have been determined in the paper. In order to reduce a negative impact of the vibration amplitude on a cutting process and quality of the machined surfaces machining must be carried out with its minimum value. In this case certain ratio of the tool vibration frequency to the work-piece rotation speed has been ensured in the paper. A formula has been obtained for calculation of this ratio with due account of the expected length of chip elements and coefficient of vibration cycle asymmetry.Influence of the asymmetric coefficient of the tool vibration cycle on roughness of the machined surfaces and cutting tool wear has been determined in the paper. According to the results pertaining to machining of work-pieces made of 45 and ШХ15 steel the paper presents mathematical relationships of machined surface roughness with cutting modes and asymmetry coefficient of tool vibration cycle. Tool feeding being one of the cutting modes exerts the most significant impact on the roughness value and increase of the tool feeding entails increase in roughness. Reduction in coefficient of vibration cycle asymmetry contributes to surface roughness reduction. However, the cutting tool wear occurs more intensive. Coefficient of the vibration cycle asymmetry must be increased in order to reduce wear rate. Therefore, the choice of the coefficient of the vibration cycle asymmetry is based on the parameters of surface roughness which must be obtained after machining and intensity of tool wear rate.The paper considers a process of turning structural steel with asymmetric

  1. Direct observation of electrothermal instability structures on intensely Ohmically heated aluminum with current flowing in a surface skin layer

    Science.gov (United States)

    Awe, Thomas

    2017-10-01

    Implosions on the Z Facility assemble high-energy-density plasmas for radiation effects and ICF experiments, but achievable stagnation pressures and temperatures are degraded by the Magneto-Rayleigh-Taylor (MRT) instability. While the beryllium liners (tubes) used in Magnetized Liner Inertial Fusion (MagLIF) experiments are astonishingly smooth (10 to 50 nm RMS roughness), they also contain distributed micron-scale resistive inclusions, and large MRT amplitudes are observed. Early in the implosion, an electrothermal instability (ETI) may provide a perturbation which greatly exceeds the initial surface roughness of the liner. Resistive inhomogeneities drive nonuniform current density and Joule heating, resulting in locally higher temperature, and thus still higher resistivity. Such unstable temperature and pressure growth produce density perturbations which seed MRT. For MagLIF liners, ETI seeding of MRT has been inferred by evaluating late-time MRT, but a direct observation of ETI is not made. ETI is directly observed on the surface of 1.0-mm-diameter solid Al rods pulsed to 1 MA in 100 ns via high resolution gated optical imaging (2 ns temporal and 3 micron spatial resolution). Aluminum 6061 alloy rods, with micron-scale resistive inclusions, consistently first demonstrate overheating from distinct, 10-micron-scale, sub-eV spots, which 5-10 ns later merge into azimuthally stretched elliptical spots and discrete strata (40-100 microns wide by 10 microns tall). Axial plasma filaments form shortly thereafter. Surface plasma can be suppressed for rods coated with dielectric, enabling extended study of the evolution of stratified ETI structures, and experimental inference of ETI growth rates. This fundamentally new and highly 3-dimensional dataset informs ETI physics, including when the ETI seed of MRT may be initiated.

  2. Excellent c-Si surface passivation by thermal atomic layer deposited aluminum oxide after industrial firing activation

    International Nuclear Information System (INIS)

    Liao, B; Stangl, R; Ma, F; Mueller, T; Lin, F; Aberle, A G; Bhatia, C S; Hoex, B

    2013-01-01

    We demonstrate that by using a water (H 2 O)-based thermal atomic layer deposited (ALD) aluminum oxide (Al 2 O 3 ) film, excellent surface passivation can be attained on planar low-resistivity silicon wafers. Effective carrier lifetime values of up to 12 ms and surface recombination velocities as low as 0.33 cm s −1 are achieved on float-zone wafers after a post-deposition thermal activation of the Al 2 O 3 passivation layer. This post-deposition activation is achieved using an industrial high-temperature firing process which is commonly used for contact formation of standard screen-printed silicon solar cells. Neither a low-temperature post-deposition anneal nor a silicon nitride capping layer is required in this case. Deposition temperatures in the 100–400 °C range and peak firing temperatures of about 800 °C (set temperature) are investigated. Photoluminescence imaging shows that the surface passivation is laterally uniform. Corona charging and capacitance–voltage measurements reveal that the negative fixed charge density near the AlO x /c-Si interface increases from 1.4 × 10 12 to 3.3 × 10 12 cm −2 due to firing, while the midgap interface defect density reduces from 3.3 × 10 11 to 0.8 × 10 11 cm −2 eV −1 . This work demonstrates that direct firing activation of thermal ALD Al 2 O 3 is feasible, which could be beneficial for solar cell manufacturing. (paper)

  3. Study of the processes of adsorption of amine-containing surface-active substance on the surface of Aluminum powder

    Directory of Open Access Journals (Sweden)

    Antonina Dyuryagina

    2012-03-01

    Full Text Available Equilibrium characteristics of adsorption on a surface of a pigment depending on concentration factors and temperature of the dispersive environment are defined. Kinetic laws of superficial activity of binary, threefold homogeneous and heterogeneous modeling systems are studied. The estimation of mechanisms of process of adsorption is carried out.

  4. Aluminum nitride coatings using response surface methodology to optimize the thermal dissipated performance of light-emitting diode modules

    Science.gov (United States)

    Jean, Ming-Der; Lei, Peng-Da; Kong, Ling-Hua; Liu, Cheng-Wu

    2018-05-01

    This study optimizes the thermal dissipation ability of aluminum nitride (AlN) ceramics to increase the thermal performance of light-emitting diode (LED) modulus. AlN powders are deposited on heat sink as a heat interface material, using an electrostatic spraying process. The junction temperature of the heat sink is developed by response surface methodology based on Taguchi methods. In addition, the structure and properties of the AlN coating are examined using X-ray photoelectron spectroscopy (XPS). In the XPS analysis, the AlN sub-peaks are observed at 72.79 eV for Al2p and 398.88 eV for N1s, and an N1s sub-peak is assigned to N-O at 398.60eV and Al-N bonding at 395.95eV, which allows good thermal properties. The results have shown that the use of AlN ceramic material on a heat sink can enhance the thermal performance of LED modules. In addition, the percentage error between the predicted and experimental results compared the quadric model with between the linear and he interaction models was found to be within 7.89%, indicating that it was a good predictor. Accordingly, RSM can effectively enhance the thermal performance of an LED, and the beneficial heat dissipation effects for AlN are improved by electrostatic spraying.

  5. Proton surface charge determination in Spodosol horizons with organically bound aluminum

    Science.gov (United States)

    Skyllberg, Ulf; Borggaard, Ole K.

    1998-05-01

    Net proton surface charge densities were determined in O, E, Bh, and Bs horizons of a sandy till, Spodosol from Denmark, by means of acid-base titration combined with ion adsorption in 0.005 M Ca(NO 3) 2 and independent permanent charge determination. The release of organic anions exceeded the adsorption of NO 3-, resulting in a desorption of anions in all horizons. Data were found to obey the law of balance between surface charges and adsorbed ions only when charges pertaining to Al and organic anions released during the titration experiments were accounted for, in addition to charges pertaining the potential determining ions (PDI) H + and OH - and the index ions Ca 2+ and NO 3-. It was furthermore shown that the point of zero net proton charge (PZNPC) in soils highly depends on the concentration of organically bound Al. Approaches previously used in soils, in which adsorbed Al n+ has been ignored (i.e., considered equivalent to nH + as a PDI), resulted in a PZNPC of 4.1 in the Bs horizon. If instead organically bound Al was accounted for as a counter-ion similar to 3/2Ca 2+, a PZNPC of 2.9 was obtained for the same Bs horizon. Based on PZNPC values estimated by the latter approach, combined with a weak-acid analog, it was shown that organic proton surface charges buffered pH with a similar intensity in the O, E, Bh, and Bs horizons of this study. Because the acidity of Al adsorbed to conjugate bases of soil organic acids is substantially weaker than the acidity of the corresponding protonated form of the organic acids, the point of zero net proton charge (PZNPC) will increase if the concentration of organically adsorbed Al increases at the expense of adsorbed H. This means that PZNPC values determined for soils with unknown concentrations of organically adsorbed Al are highly operational and not very meaningful as references.

  6. A surface-analytical examination of stringer particles in aluminum-lithium-copper alloys

    Science.gov (United States)

    Larson, L. A.; Avalos-Borja, M.; Pizzo, P. P.

    1984-01-01

    A surface analytical examination of powder metallurgy processed Al-Li-Cu alloys was conducted. The oxide stringer particles often found in these alloys are characterized. Particle characterization is important to more fully understand their impact on the stress corrosion and fracture properties of the alloy. The techniques used where SIMS (Secondary Ion Mass Spectroscopy) and SAM (Scanning Auger Microscopy). The results indicate that the oxide stringer particles contain both Al and LI with relatively high Li content and the Li compounds may be associated with the stringer particles, thereby locally depleting the adjacent matrix of Li solute.

  7. Machine vision method for online surface inspection of easy open can ends

    Science.gov (United States)

    Mariño, Perfecto; Pastoriza, Vicente; Santamaría, Miguel

    2006-10-01

    Easy open can end manufacturing process in the food canning sector currently makes use of a manual, non-destructive testing procedure to guarantee can end repair coating quality. This surface inspection is based on a visual inspection made by human inspectors. Due to the high production rate (100 to 500 ends per minute) only a small part of each lot is verified (statistical sampling), then an automatic, online, inspection system, based on machine vision, has been developed to improve this quality control. The inspection system uses a fuzzy model to make the acceptance/rejection decision for each can end from the information obtained by the vision sensor. In this work, the inspection method is presented. This surface inspection system checks the total production, classifies the ends in agreement with an expert human inspector, supplies interpretability to the operators in order to find out the failure causes and reduce mean time to repair during failures, and allows to modify the minimum can end repair coating quality.

  8. Advanced Electrochemical Machining (ECM) for tungsten surface micro-structuring in blanket applications

    Energy Technology Data Exchange (ETDEWEB)

    Holstein, Nils, E-mail: nils.holstein@kit.edu [Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Baden-Württemberg (Germany); Krauss, Wolfgang; Konys, Jürgen [Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Baden-Württemberg (Germany); Heuer, Simon; Weber, Thomas [Research Center Jülich, Institute of Energy- and Climate Research – Plasma Physics (IEK-4), D-52425 Jülich (Germany)

    2016-11-01

    Highlights: • Electrochemical Machining is an appropriate tool for tungsten shaping. • Progress in shaping achieved by combination of ECM with advanced micro-lithography. • Application in First Wall for connection of plasma facing material to breeder blanket. • Successful development of adhesion promotors by ECM for plasma spraying interlayers. • Microstructure electrochemical manufacturing of tungsten in sizes of 100 μm achieved. - Abstract: Plasma facing components for fusion applications must have to exhibit long-term stability under extreme physical conditions, and therefore any material imperfections caused by mechanical and/or thermal stresses in the shaping processes cannot be tolerated due to a high risk of possible technical failures under fusion conditions. To avoid such defects, the method of Electrochemical Machining (ECM) enables a complete defect-free processing of removal of tungsten material during the desired shaping, also for high penetration depths. Furthermore, supported by lithographic mask pretreatment, three-dimensional distinct geometric structures can be positive-imaged via the directional galvanic dissolution applying M-ECM process into the tungsten bulk material. New required applications for tungsten components, e.g. as adhesion promotors in W-surfaces to enable sure grip and bonding of thick plasma-spraying layers for blanket components, will define the way of further miniaturization of well-established millimeter dimensioned M-ECM shaping processes to dimensions of 100 μm and furthermore down to 50 μm. Besides current M-ECM limits the article describes inevitable needs of further developments for mask resists, mask materials and the resulting ECM parameters, to reach the needed accuracy in tungsten microstructure. The achieved progress and observed correlations of processing parameters will be manifested by produced demonstrators made by the new “μM”-ECM process.

  9. Advanced Electrochemical Machining (ECM) for tungsten surface micro-structuring in blanket applications

    International Nuclear Information System (INIS)

    Holstein, Nils; Krauss, Wolfgang; Konys, Jürgen; Heuer, Simon; Weber, Thomas

    2016-01-01

    Highlights: • Electrochemical Machining is an appropriate tool for tungsten shaping. • Progress in shaping achieved by combination of ECM with advanced micro-lithography. • Application in First Wall for connection of plasma facing material to breeder blanket. • Successful development of adhesion promotors by ECM for plasma spraying interlayers. • Microstructure electrochemical manufacturing of tungsten in sizes of 100 μm achieved. - Abstract: Plasma facing components for fusion applications must have to exhibit long-term stability under extreme physical conditions, and therefore any material imperfections caused by mechanical and/or thermal stresses in the shaping processes cannot be tolerated due to a high risk of possible technical failures under fusion conditions. To avoid such defects, the method of Electrochemical Machining (ECM) enables a complete defect-free processing of removal of tungsten material during the desired shaping, also for high penetration depths. Furthermore, supported by lithographic mask pretreatment, three-dimensional distinct geometric structures can be positive-imaged via the directional galvanic dissolution applying M-ECM process into the tungsten bulk material. New required applications for tungsten components, e.g. as adhesion promotors in W-surfaces to enable sure grip and bonding of thick plasma-spraying layers for blanket components, will define the way of further miniaturization of well-established millimeter dimensioned M-ECM shaping processes to dimensions of 100 μm and furthermore down to 50 μm. Besides current M-ECM limits the article describes inevitable needs of further developments for mask resists, mask materials and the resulting ECM parameters, to reach the needed accuracy in tungsten microstructure. The achieved progress and observed correlations of processing parameters will be manifested by produced demonstrators made by the new “μM”-ECM process.

  10. Study on Crystallographic Orientation Effect on Surface Generation of Aluminum in Nano-cutting.

    Science.gov (United States)

    Xu, Feifei; Fang, Fengzhou; Zhu, Yuanqing; Zhang, Xiaodong

    2017-12-01

    The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}, {110}, and {111}, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

  11. Surface study of gallium- and aluminum- doped graphenes upon adsorption of cytosine: DFT calculations

    International Nuclear Information System (INIS)

    Shokuhi Rad, Ali; Zareyee, Daryoush; Peyravi, Majid; Jahanshahi, Mohsen

    2016-01-01

    Highlights: • P1 and P4 are the most stable adsorption configurations for cytosine. • NBO analysis show n-type semiconductor property for both Al- and Ga-doped graphenes. • Important changes in the HOMO and LUMO of doped graphene upon adsorption of cytosine. • Increase in the conductivity of system when cytosine is adsorbed on doped graphenes. - Abstract: The adsorption of cytosine molecule on Al- and Ga- doped graphenes is studied using first-principles density functional theory (DFT) calculations. The energetically most stable geometries of cytosine on both Al- and Ga- doped graphenes are determined and the adsorption energies are calculated. The net charge of transfer as well as local charge of doped atoms upon adsorption of cytosine are studied by natural bond orbitals (NBO) analysis. Orbital hybridizing of complexes was searched by frontier molecular orbital theory (FMO), and density of states (DOS). Depending on the side of cytosine, there are four possible sites for its adsorption on doped graphene; denoted as P1, P2, P3, and P4, respectively. The order of binding energy in the case of Al-doped graphene is found as P1 > P4 > P3 > P2. Interestingly, the order in the case of Ga-doped graphene changes to: P4 ∼ P1 > P3 > P2. Both surfaces show superior adsorbent property, resulting chemisorption of cytosine, especially at P1 and P4 position configurations. The NBO charge analysis reveals that the charge transfers from Al- and Ga- doped graphene sheets to cytosine. The electronic properties of both surfaces undertake important changes after cytosine adsorption, which indicates notable change in its electrical conductivity.

  12. Surface study of gallium- and aluminum- doped graphenes upon adsorption of cytosine: DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Shokuhi Rad, Ali, E-mail: a.shokuhi@gmail.com [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Zareyee, Daryoush [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Peyravi, Majid; Jahanshahi, Mohsen [Faculty of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

    2016-12-30

    Highlights: • P1 and P4 are the most stable adsorption configurations for cytosine. • NBO analysis show n-type semiconductor property for both Al- and Ga-doped graphenes. • Important changes in the HOMO and LUMO of doped graphene upon adsorption of cytosine. • Increase in the conductivity of system when cytosine is adsorbed on doped graphenes. - Abstract: The adsorption of cytosine molecule on Al- and Ga- doped graphenes is studied using first-principles density functional theory (DFT) calculations. The energetically most stable geometries of cytosine on both Al- and Ga- doped graphenes are determined and the adsorption energies are calculated. The net charge of transfer as well as local charge of doped atoms upon adsorption of cytosine are studied by natural bond orbitals (NBO) analysis. Orbital hybridizing of complexes was searched by frontier molecular orbital theory (FMO), and density of states (DOS). Depending on the side of cytosine, there are four possible sites for its adsorption on doped graphene; denoted as P1, P2, P3, and P4, respectively. The order of binding energy in the case of Al-doped graphene is found as P1 > P4 > P3 > P2. Interestingly, the order in the case of Ga-doped graphene changes to: P4 ∼ P1 > P3 > P2. Both surfaces show superior adsorbent property, resulting chemisorption of cytosine, especially at P1 and P4 position configurations. The NBO charge analysis reveals that the charge transfers from Al- and Ga- doped graphene sheets to cytosine. The electronic properties of both surfaces undertake important changes after cytosine adsorption, which indicates notable change in its electrical conductivity.

  13. MM99.50 - Surface Topography Characterization Using an Atomic Force Microscope Mounted on a Coordinate Measuring Machine

    DEFF Research Database (Denmark)

    Chiffre, Leonardo De; Hansen, Hans Nørgaard; Kofod, Niels

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...

  14. A new geometrical construction using rounded surfaces proposed for the transverse flux machine for direct drive wind turbine

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Nica, Florin Valentin Traian; Ritchie, Ewen

    2014-01-01

    This paper proposes a new construction for transverse flux machines (TFM) using a rounded surfaces core geometry. The new concept has been developed for TFM with U core geometry. In this case a new analytic design procedure was proposed. The analytic design of the new TFM construction is further ...... proposed concept is more attractive for the direct-drive wind turbine application....

  15. Evaluation on machined surface of hardened stainless steel generated by hard turning using coated carbide tools with wiper geometry

    International Nuclear Information System (INIS)

    Noordin, M.Y.; Kurniawan, D.; Sharif, S.

    2007-01-01

    Hard turning has been explored to be the finish machining operation for parts made of hardened steel. Its feasibility is determined partially by the quality of the resulting machined surface. This study evaluates the surface integrity of martensitic stainless steel (48 HRC) resulting from hard turning using coated carbide tool with wiper geometry at various cutting speed and feed and compares to that obtained using coated carbide tool with conventional geometry. The wiper coated carbide tool is able to produce machined surface which is of finer finish (Ra is finer than 0.4 μm at most cutting parameters) and yet is similarly inducing only minor microstructural alteration compared to its conventional counterpart. From the view of the chip morphology where continuous type of chip is desired rather than sawtooth chip type, the wiper tool generates continuous chip at almost similar range of cutting parameters compared to the case when using conventional tool. Additionally, the use of wiper tool also induces the preferred compressive residual stress at the machined surface. (author)

  16. Surface texturing of Si3N4–SiC ceramic tool components by pulsed laser machining

    CSIR Research Space (South Africa)

    Tshabalala, LC

    2016-03-01

    Full Text Available Traditional abrasive techniques such as grinding and lapping have long been used in the surface conditioning of engineering materials. However, in the processing of hard and brittle materials like silicon nitride (Si(sub3)N(sub4)), machining...

  17. EVALUATION OF MACHINABILITY OF DUCTILE IRONS ALLOYED WITH Ni AND Cu IN TERMS OF CUTTING FORCES AND SURFACE QUALITY

    Directory of Open Access Journals (Sweden)

    Yücel AŞKUN

    2003-02-01

    Full Text Available Due to the enhanced strength, ductility and thoughness of Ductile Iron (DI when compared to the other types cast iron, its machinability is relatively poor. When a steel part is replaced with ductile iron, however, better machinability is considered to be the most important gain. This study presents the results of machining tests of ductile irons alloyed with Ni and Cu at various contents to determine the effect of their microstructure and mechanical properties on cutting forces and surface roughness. Six different specimen groups of ductile iron alloyed with various amounts of nickel and copper were subjected to machining tests and their machinabilities were investigated based on cutting forces and surface roughness criteria. The results were evaluated according to microstructure and mechanical properties of specimens determined before. In terms of both criterion, the best result obtained was specimen added 0.7 % Ni and 0.7 % Cu. When the specimens were evaluated according to their mechanical properties, the specimens alloyed 1 % Ni and 0.65 % Cu seemed promising.

  18. Analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy - 276

    International Nuclear Information System (INIS)

    Khidhir, Basim A; Mohamed, Bashir

    2011-01-01

    Machining parameters has an important factor on tool wear and surface finish, for that the manufacturers need to obtain optimal operating parameters with a minimum set of experiments as well as minimizing the simulations in order to reduce machining set up costs. The cutting speed is one of the most important cutting parameter to evaluate, it clearly most influences on one hand, tool life, tool stability, and cutting process quality, and on the other hand controls production flow. Due to more demanding manufacturing systems, the requirements for reliable technological information have increased. For a reliable analysis in cutting, the cutting zone (tip insert-workpiece-chip system) as the mechanics of cutting in this area are very complicated, the chip is formed in the shear plane (entrance the shear zone) and is shape in the sliding plane. The temperature contributed in the primary shear, chamfer and sticking, sliding zones are expressed as a function of unknown shear angle on the rake face and temperature modified flow stress in each zone. The experiments were carried out on a CNC lathe and surface finish and tool tip wear are measured in process. Machining experiments are conducted. Reasonable agreement is observed under turning with high depth of cut. Results of this research help to guide the design of new cutting tool materials and the studies on evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy - 276 machining.

  19. The microstructure of aluminum A5083 butt joint by friction stir welding

    International Nuclear Information System (INIS)

    Jasri, M. A. H. M.; Afendi, M.; Ismail, A.; Ishak, M.

    2015-01-01

    This study presents the microstructure of the aluminum A5083 butt joint surface after it has been joined by friction stir welding (FSW) process. The FSW process is a unique welding method because it will not change the chemical properties of the welded metals. In this study, MILKO 37 milling machine was modified to run FSW process on 4 mm plate of aluminum A5083 butt joint. For the experiment, variables of travel speed and tool rotational speed based on capability of machine were used to run FSW process. The concentrated heat from the tool to the aluminum plate changes the plate form from solid to plastic state. Two aluminum plates is merged to become one plate during plastic state and return to solid when concentrated heat is gradually further away. After that, the surface and cross section of the welded aluminum were investigated with a microscope by 400 x multiplication zoom. The welding defect in the FSW aluminum was identified. Then, the result was compared to the American Welding Society (AWS) FSW standard to decide whether the plate can be accepted or rejected

  20. The microstructure of aluminum A5083 butt joint by friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Jasri, M. A. H. M.; Afendi, M. [School of Mechatronic Engineering, Universiti Malaysia Perlis, Pauh, 02600, Arau, Perlis (Malaysia); Ismail, A. [UniKL MIMET, JalanPantaiRemis, 32200, Lumut, Perak (Malaysia); Ishak, M. [Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 02600, Pekan, Pahang (Malaysia)

    2015-05-15

    This study presents the microstructure of the aluminum A5083 butt joint surface after it has been joined by friction stir welding (FSW) process. The FSW process is a unique welding method because it will not change the chemical properties of the welded metals. In this study, MILKO 37 milling machine was modified to run FSW process on 4 mm plate of aluminum A5083 butt joint. For the experiment, variables of travel speed and tool rotational speed based on capability of machine were used to run FSW process. The concentrated heat from the tool to the aluminum plate changes the plate form from solid to plastic state. Two aluminum plates is merged to become one plate during plastic state and return to solid when concentrated heat is gradually further away. After that, the surface and cross section of the welded aluminum were investigated with a microscope by 400 x multiplication zoom. The welding defect in the FSW aluminum was identified. Then, the result was compared to the American Welding Society (AWS) FSW standard to decide whether the plate can be accepted or rejected.

  1. Local charge exchange of He{sup +} ions at Aluminum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, P., E-mail: pierfrancesco.riccardi@fis.unical.it [Dipartimento di Fisica, Università della Calabria and INFN – Gruppo collegato di Cosenza, Via P. Bucci cubo 33C, Arcavacata di Rende, Cosenza (Italy); Sindona, A. [Dipartimento di Fisica, Università della Calabria and INFN – Gruppo collegato di Cosenza, Via P. Bucci cubo 33C, Arcavacata di Rende, Cosenza (Italy); Dukes, C.A. [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering University of Virginia, Charlottesville, VA 22904 (United States)

    2017-04-04

    We report on experiments designed to observe the correlation between the autoionization of doubly excited helium atoms and the Auger decay of 2p vacancies in Al. The autoionizing states are formed when incident He{sup +*} and He{sup ++} are neutralized by resonant electron capture at the surface. 2p excitation in Al occurs in dielectronic charge transfer during the close encounter of an excited helium ion and an Al atom. These results clarify the mechanism for Al-2p excitation in the case of singly charged ground state He{sup +}(1s) ion impact, where the dielectronic transition occurs after promotion of the 1s electron of incoming ions. - Highlights: • We observe the correlation between autoionization of doubly excited helium atoms and the Auger decay of 2p vacancies in Al. • 2p excitation in Al occurs in dielectronic charge transfer during the close encounter of an excited helium ion and an Al atom. • These results clarify the mechanism for Al-2p excitation in the case of singly charged ground state He{sup +}(1s) ion impact.

  2. Studies of the mechanisms involved in the laser surface hardening process of aluminum base alloys

    International Nuclear Information System (INIS)

    Silva, Luciana Ventavele da

    2011-01-01

    The Al-Si alloys are widely used in industry to replace the steel and gray cast iron in high-tech sectors. The commercial importance of these alloys is mainly due to its low weight, excellent wear (abrasion) and corrosion resistance, high resistance at elevated temperatures, low coefficient of thermal expansion and lesser fuel consumption that provide considerable reduction of emission of pollutants. In this work, Al-Si alloy used in the automotive industry to manufacture pistons of internal combustion engines, was undergone to surface treatments using LASER remelting (Nd:YAG, λ = 1.06 μm, pulsed mode). The LASER enables various energy concentrations with accurate transfer to the material without physical contact. The intense energy transfer causes the occurrence of structural changes in the superficial layer of the material. Experiments with single pulses and trails were conducted under various conditions of LASER processing in order to analyze microstructural changes resulting from treatments and their effects on the hardness. For the characterization of hardened layer was utilized the following techniques: optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray mapping, Vickers microhardness and maximum roughness tests. The high cooling rate caused a change in the alloy structure due to the refinement of the primary eutectic silicon particles, resulting in increase of the mechanical properties (hardness) of the Al-Si alloy. (author)

  3. Surface modification of an aluminum alloy by electron beam introducing TiCN nanoparticles

    Science.gov (United States)

    Kolev, M.; Dimitrova, R.; Parshorov, St.; Valkov, St.; Lazarova, R.; Petrov, P.

    2018-03-01

    TiCN nanopowder deposited in an appropriate way on the surface of an AlSi12Cu2NiMg substrate was incorporated in the matrix using an electron beam technology. The samples were studied by means of light microscopy, SEM, and EDX; their microhardness was also determined. The formation was found of a uniform and dense coating with a thickness of 7 – 10 μgm with a good adherence to the substrate. A modified zone appeared under the coating with a thickness of 100 – 150 μgm containing dendrites of an α-solid solution and a fine eutectic between them, as well as primary silicon crystals. The microhardness of this modified zone was up to 2.4 times higher than that of the matrix. The results of SEM and EDX studies revealed unambiguously the presence of titanium in the coating and in the zones below it. Obviously, the electron beam treatment resulted in the TiCN nanoparticles penetrating into the coating and the substrate immediately below the coating.

  4. Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment

    Directory of Open Access Journals (Sweden)

    D. Tahir

    2014-08-01

    Full Text Available The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF by using QUEELS-ε(k-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.

  5. A Review of Additive Mixed-Electric Discharge Machining: Current Status and Future Perspectives for Surface Modification of Biomedical Implants

    Directory of Open Access Journals (Sweden)

    Abdul’Azeez Abdu Aliyu

    2017-01-01

    Full Text Available Surface treatment remained a key solution to numerous problems of synthetic hard tissues. The basic methods of implant surface modification include various physical and chemical deposition techniques. However, most of these techniques have several drawbacks such as excessive cost and surface cracks and require very high sintering temperature. Additive mixed-electric discharge machining (AM-EDM is an emerging technology which simultaneously acts as a machining and surface modification technique. Aside from the mere molds, dies, and tool fabrication, AM-EDM is materializing to finishing of automobiles and aerospace, nuclear, and biomedical components, through the concept of material migrations. The mechanism of material transfer by AM-EDM resembles electrophoretic deposition, whereby the additives in the AM-EDM dielectric fluids are melted and migrate to the machined surface, forming a mirror-like finishing characterized by extremely hard, nanostructured, and nanoporous layers. These layers promote the bone in-growth and strengthen the cell adhesion. Implant shaping and surface treatment through AM-EDM are becoming a key research focus in recent years. This paper reports and summarizes the current advancement of AM-EDM as a potential tool for orthopedic and dental implant fabrication. Towards the end of this paper, the current challenges and future research trends are highlighted.

  6. Effects of cutting parameters and machining environments on surface roughness in hard turning using design of experiment

    Science.gov (United States)

    Mia, Mozammel; Bashir, Mahmood Al; Dhar, Nikhil Ranjan

    2016-07-01

    Hard turning is gradually replacing the time consuming conventional turning process, which is typically followed by grinding, by producing surface quality compatible to grinding. The hard turned surface roughness depends on the cutting parameters, machining environments and tool insert configurations. In this article the variation of the surface roughness of the produced surfaces with the changes in tool insert configuration, use of coolant and different cutting parameters (cutting speed, feed rate) has been investigated. This investigation was performed in machining AISI 1060 steel, hardened to 56 HRC by heat treatment, using coated carbide inserts under two different machining environments. The depth of cut, fluid pressure and material hardness were kept constant. The Design of Experiment (DOE) was performed to determine the number and combination sets of different cutting parameters. A full factorial analysis has been performed to examine the effect of main factors as well as interaction effect of factors on surface roughness. A statistical analysis of variance (ANOVA) was employed to determine the combined effect of cutting parameters, environment and tool configuration. The result of this analysis reveals that environment has the most significant impact on surface roughness followed by feed rate and tool configuration respectively.

  7. Modeling of the integrity of machining surfaces: application to the case of 15-5 PH stainless steel finish turning

    International Nuclear Information System (INIS)

    Mondelin, A.

    2012-01-01

    During machining, extreme conditions of pressure, temperature and strain appear in the cutting zone. In this thermo-mechanical context, the link between the cutting conditions (cutting speed, lubrication, feed rate, wear, tool coating...) and the machining surface integrity represents a major scientific target. This PhD study is a part of a global project called MIFSU (Modeling of the Integrity and Fatigue resistance of Machining Surfaces) and it focuses on the finish turning of the 15-5PH (a martensitic stainless steel used for parts of helicopter rotor). Firstly, material behavior has been studied in order to provide data for machining simulations. Stress-free dilatometry tests were conducted to obtain the austenitization kinetics of 15-5PH steel for high heating rates (up to 11,000 degrees C/s). Then, parameters of Leblond metallurgical model have been calibrated. In addition, dynamic compression tests (de/dt ranging from 0.01 to 80/s and e ≥ 1) have been performed to calibrate a strain-rate dependent elasto-plasticity model (for high strains). These tests also helped to highlight the dynamic recrystallization phenomena and their influence on the flow stress of the material. Thus, recrystallization model has also been implemented.In parallel, a numerical model for the prediction of machined surface integrity has been constructed. This model is based on a methodology called 'hybrid' (developed during the PhD thesis of Frederic Valiorgue for the AISI 304L steel). The method consists in replacing tool and chip modeling by equivalent loadings (obtained experimentally). A calibration step of these loadings has been carried out using orthogonal cutting and friction tests (with sensitivity studies of machining forces, friction and heat partition coefficients to cutting parameters variations).Finally, numerical simulations predictions of microstructural changes (austenitization and dynamic recrystallization) and residual stresses have been successfully compared with

  8. Comparative study for different statistical models to optimize cutting parameters of CNC end milling machines

    International Nuclear Information System (INIS)

    El-Berry, A.; El-Berry, A.; Al-Bossly, A.

    2010-01-01

    In machining operation, the quality of surface finish is an important requirement for many work pieces. Thus, that is very important to optimize cutting parameters for controlling the required manufacturing quality. Surface roughness parameter (Ra) in mechanical parts depends on turning parameters during the turning process. In the development of predictive models, cutting parameters of feed, cutting speed, depth of cut, are considered as model variables. For this purpose, this study focuses on comparing various machining experiments which using CNC vertical machining center, work pieces was aluminum 6061. Multiple regression models are used to predict the surface roughness at different experiments.

  9. Determination of High-Frequency d- and q-axis Inductances for Surface-Mounted Permanent-Magnet Synchronous Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Vetuschi, M.; Rasmussen, Peter Omand

    2010-01-01

    This paper presents a reliable method for the experimental determination of high-frequency d- and q -axis inductances for surface-mounted permanent-magnet synchronous machines (SMPMSMs). Knowledge of the high-frequency d- and q-axis inductances plays an important role in the efficient design...... of sensorless controllers using high-frequency signal injection techniques. The proposed method employs a static locked-rotor test using an ac +dc power supply. By injecting a high-frequency rotating voltage vector into the machine, the d- and q-axis inductances may simultaneously be determined with no need...

  10. Exact analytical modeling of magnetic vector potential in surface inset permanent magnet DC machines considering magnet segmentation

    Science.gov (United States)

    Jabbari, Ali

    2018-01-01

    Surface inset permanent magnet DC machine can be used as an alternative in automation systems due to their high efficiency and robustness. Magnet segmentation is a common technique in order to mitigate pulsating torque components in permanent magnet machines. An accurate computation of air-gap magnetic field distribution is necessary in order to calculate machine performance. An exact analytical method for magnetic vector potential calculation in surface inset permanent magnet machines considering magnet segmentation has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in polar coordinate by using sub-domain method. One of the main contributions of the paper is to derive an expression for the magnetic vector potential in the segmented PM region by using hyperbolic functions. The developed method is applied on the performance computation of two prototype surface inset magnet segmented motors with open circuit and on load conditions. The results of these models are validated through FEM method.

  11. Potential of cancer screening with serum surface-enhanced Raman spectroscopy and a support vector machine

    International Nuclear Information System (INIS)

    Li, S X; Zhang, Y J; Zeng, Q Y; Li, L F; Guo, Z Y; Liu, Z M; Xiong, H L; Liu, S H

    2014-01-01

    Cancer is the most common disease to threaten human health. The ability to screen individuals with malignant tumours with only a blood sample would be greatly advantageous to early diagnosis and intervention. This study explores the possibility of discriminating between cancer patients and normal subjects with serum surface-enhanced Raman spectroscopy (SERS) and a support vector machine (SVM) through a peripheral blood sample. A total of 130 blood samples were obtained from patients with liver cancer, colonic cancer, esophageal cancer, nasopharyngeal cancer, gastric cancer, as well as 113 blood samples from normal volunteers. Several diagnostic models were built with the serum SERS spectra using SVM and principal component analysis (PCA) techniques. The results show that a diagnostic accuracy of 85.5% is acquired with a PCA algorithm, while a diagnostic accuracy of 95.8% is obtained using radial basis function (RBF), PCA–SVM methods. The results prove that a RBF kernel PCA–SVM technique is superior to PCA and conventional SVM (C-SVM) algorithms in classification serum SERS spectra. The study demonstrates that serum SERS, in combination with SVM techniques, has great potential for screening cancerous patients with any solid malignant tumour through a peripheral blood sample. (letters)

  12. Effect of He+ fluence on surface morphology and ion-irradiation induced defect evolution in 7075 aluminum alloys

    Science.gov (United States)

    Ni, Kai; Ma, Qian; Wan, Hao; Yang, Bin; Ge, Junjie; Zhang, Lingyu; Si, Naichao

    2018-02-01

    The evolution of microstructure for 7075 aluminum alloys with 50 Kev helium ions irradiation were studied by using optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM). The fluences of 1 × 1015, 1 × 1016 and 1 × 1017 ions cm-2 were selected, and irradiation experiments were conducted at room temperatures. The transmission process of He+ ions was simulated by using SRIM software, including distribution of ion ranges, energy losses and atomic displacements. Experimental results show that irradiated pits and micro-cracks were observed on irradiation sample surface, and the size of constituent particles (not including Mg2Si) decreased with the increasing dose. The x-ray diffraction results of the pair of peaks is better resolved in irradiated samples might indicate that the stressed structure consequence due to crystal defects (vacancies and interstitials) after He+ implantation. TEM observation indicated that the density of MgZn2 phase was significantly reduced after helium ion irradiation which is harmful to strength. Besides, the development of compressive stress produced a large amount of dislocation defects in the 1015 ions cm-2 sample. Moreover, higher fluence irradiation produced more dislocations in sample. At fluence of 1016 ions cm-2, dislocation wall formed by dislocation slip and aggregation in the interior of grains, leading to the refinement of these grains. As fluence increased to 1017 ions cm-2, dislocation loops were observed in pinned dislocation. Moreover, dislocation as effective defect sink, irradiation-induced vacancy defects aggregated to these sinks, and resulted in the formation of helium bubbles in dislocation.

  13. Influence of Chatter of VMC Arising During End Milling Operation and Cutting Conditions on Quality of Machined Surface

    Directory of Open Access Journals (Sweden)

    A.K.M.N. Amin, M.A. Rizal, and M. Razman

    2012-08-01

    Full Text Available Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC, which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.

  14. Terahertz acoustic phonon detection from a compact surface layer of spherical nanoparticles powder mixture of aluminum, alumina and multi-walled carbon nanotube

    Science.gov (United States)

    Abouelsayed, A.; Ebrahim, M. R.; El hotaby, W.; Hassan, S. A.; Al-Ashkar, Emad

    2017-10-01

    We present terahertz spectroscopy study on spherical nanoparticles powder mixture of aluminum, alumina, and MWCNTs induced by surface mechanical attrition treatment (SMAT) of aluminum substrates. Surface alloying of AL, Al2O3 0.95% and MWCNTs 0.05% powder mixture was produced during SMAT process, where a compact surface layer of about 200 μm due to ball bombardment was produced from the mixture. Al2O3 alumina powder played a significant role in MWCNTs distribution on surface, those were held in deformation surface cites of micro-cavities due to SMAT process of Al. The benefits are the effects on resulted optical properties of the surface studied at the terahertz frequency range due to electrical isolation confinement effects and electronic resonance disturbances exerted on Al electronic resonance at the same range of frequencies. THz acoustic phonon around 0.53-0.6 THz (17-20 cm-1) were observed at ambient conditions for the spherical nanoparticles powder mixture of Al, Al2O3 and MWCNTs. These results suggested that the presence of Al2O3 and MWCNTs during SMAT process leads to the optically detection of such acoustic phonon in the THz frequency range.

  15. Cooling rate and microstructure of surface layers of 5KhNM steel, machined by electroerosion method

    International Nuclear Information System (INIS)

    Foteev, N.K.; Ploshkin, V.V.; Lyakishev, V.A.; Shirokov, S.V.

    1982-01-01

    The cooling rate and microstructure of surface layers of steel 5KhNM machined by electroerosion method have been studied. It is shown that the difference in heating rate of the surface layers with electric discharge over the 5KhNM steel samples depth results in the intensive size reduction of the microstructure. In the surface layer alongside with martensite residual austenite is present, the lattice period of which increases with the increase of pulse duration, carbide phase of complex composition appears, and concentrational heterogeneity in alloying elements (except carbon) is absent

  16. Cooling rate and microstructure of surface layers of 5KhNM steel, machined by electroerosion method

    Energy Technology Data Exchange (ETDEWEB)

    Foteev, N.K.; Ploshkin, V.V.; Lyakishev, V.A.; Shirokov, S.V.

    1982-01-01

    The cooling rate and microstructure of surface layers of steel 5KhNM machined by electroerosion method have been studied. It is shown that the difference in heating rate of the surface layers with electric discharge over the 5KhNM steel samples depth results in the intensive size reduction of the microstructure. In the surface layer alongside with martensite residual austenite is present, the lattice period of which increases with the increase of pulse duration, carbide phase of complex composition appears, and concentrational heterogeneity in alloying elements (except carbon) is absent.

  17. Influence of abrasive machining on Fe3AI intermetal surface texture

    OpenAIRE

    A. Patejuk; M. Poniatowska

    2008-01-01

    Thc paper prcscnts the results of analyzing thc surfacc tcxtilrc of sarnplcs obtaincd in thc proccss or casting with thc usc of thc Fc7AIintcrmctollic phasc altcr sclccrcd abrasivc machining opt ions havc bccn applicd - milling. wct polishing, l'hc annIysis of ihc surracctcxturc aftcr machining was carricd out by examining such pararnctcrs as: Rn. Rz. RSm. and thc profitc fi~nction- thc lnatcrial ratio curvcand thc nmpli!udc dcnsity cunc.

  18. Surface treatment by electric discharge machining of Ti–6Al–4V alloy for potential application in orthopaedics

    Czech Academy of Sciences Publication Activity Database

    Harcuba, P.; Bačáková, Lucie; Stráský, J.; Bačáková, Markéta; Novotná, Katarína; Janeček, M.

    2012-01-01

    Roč. 7, MAR (2012), s. 96-105 ISSN 1751-6161. [Symposium on Biological Materials Science /7./. San Diego, 27.02.2011-03.03.2011] R&D Projects: GA TA ČR(CZ) TA01011141 Institutional research plan: CEZ:AV0Z50110509 Keywords : electric discharge machining * surface roughness * mechanical properties Subject RIV: FI - Traumatology, Orthopedics Impact factor: 2.368, year: 2012

  19. Proton and aluminum binding properties of organic acids in surface waters of the northeastern U.S.

    Science.gov (United States)

    Fakhraei, Habibollah; Driscoll, Charles T

    2015-03-03

    A variety of mathematical estimators have been used to quantify the degree of protonation of naturally occurring organic acids. These estimators range from monoprotic, diprotic, and triprotic analog models to the discrete and continuous (Gaussian) distributions of a single proton binding-dissociation. Natural water samples from two long-term monitoring programs in the northeastern U.S. were used to quantify proton- and aluminum-binding properties of naturally occurring organic matter. Water chemistry observations were clustered into 0.05 pH intervals (over 3.75-7.35 pH range) and fit to a triprotic analog model. The model optimization indicates that about 5% of dissolved organic carbon participates in ion binding, and organic acids are composed of both strong and weak acids (i.e., pKa1 = 2.54, pKa2 = 6.19, and pKa3 = 7.52 for Adirondack samples). Binding between organic acids and aluminum can substantially influence the acid behavior of dissolved organic matter and the availability of the toxic form of aluminum (i.e., inorganic monomeric aluminum).

  20. Mesoporous aluminum phosphite

    International Nuclear Information System (INIS)

    El Haskouri, Jamal; Perez-Cabero, Monica; Guillem, Carmen; Latorre, Julio; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro

    2009-01-01

    High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S + I - surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N 2 adsorption-desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed. - Abstract: TEM image of the mesoporous aluminum phosphite showing the hexagonal disordered pore array that is generated by using surfactant micelles as template. Also a scheme emphasizing the presence of an alumina-rich core and an ALPO-like pore surface is presented.

  1. 40 CFR 63.5753 - How do I calculate the combined organic HAP content of aluminum wipedown solvents and aluminum...

    Science.gov (United States)

    2010-07-01

    ... HAP content of aluminum wipedown solvents and aluminum recreational boat surface coatings? 63.5753... Standards for Hazardous Air Pollutants for Boat Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5753 How do I calculate the combined organic HAP content of aluminum...

  2. Abbreviated machining schedule for fabricating beryllium parts free of surface damage

    International Nuclear Information System (INIS)

    Beitscher, S.; Capes, J.F.; Leslie, W.W.; Luckow, J.R.; Riegel, R.L.

    1979-01-01

    This study was performed to develop a more economical method of machining damage-free beryllium components at Rocky Flats. The present method involves a 9-pass schedule of lathe turning followed by a chemical etch. Prototype beryllium hemispherical shell parts and cylindrical tensile specimens machined to simulate the parts were utilized in this study. The main investigative methods used to evaluate the amount of machining damage were metallography and tensile tests. It was found that damage-free parts could be produced by carefully controlled machining if the number of machining passes was reduced to 4 or even 3, if followed by the standard etching treatment. These findings were made on Select S-65 grade beryllium, and probably apply to other common grades of powder source beryllium but not necessarily to ingot-source beryllium. It is recommended that the 4-pass schedule becomes the standard method to produce damage-free beryllium derived from powder. Significant savings in time, labor, and equipment can be realized by this change in method without decreasing the quality of the product

  3. Weld Repair of Thin Aluminum Sheet

    Science.gov (United States)

    Beuyukian, C. S.; Mitchell, M. J.

    1986-01-01

    Weld repairing of thin aluminum sheets now possible, using niobium shield and copper heat sinks. Refractory niobium shield protects aluminum adjacent to hole, while copper heat sinks help conduct heat away from repair site. Technique limits tungsten/inert-gas (TIG) welding bombardment zone to melt area, leaving surrounding areas around weld unaffected. Used successfully to repair aluminum cold plates on Space Shuttle, Commercial applications, especially in sealing fractures, dents, and holes in thin aluminum face sheets or clad brazing sheet in cold plates, heat exchangers, coolers, and Solar panels. While particularly suited to thin aluminum sheet, this process also used in thicker aluminum material to prevent surface damage near weld area.

  4. Gas evolution behavior of aluminum in mortar

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs.

  5. Gas evolution behavior of aluminum in mortar

    International Nuclear Information System (INIS)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs

  6. Kinetics of Accumulation of Damage in Surface Layers of Lithium-Containing Aluminum Alloys in Fatigue Tests with Rigid Loading Cycle and Corrosive Effect of Environment

    Science.gov (United States)

    Morozova, L. V.; Zhegina, I. P.; Grigorenko, V. B.; Fomina, M. A.

    2017-07-01

    High-resolution methods of metal physics research including electron, laser and optical microscopy are used to study the kinetics of the accumulation of slip lines and bands and the corrosion damage in the plastic zone of specimens of aluminum-lithium alloys 1441 and B-1469 in rigid-cycle fatigue tests under the joint action of applied stresses and corrosive environment. The strain parameters (the density of slip bands, the sizes of plastic zones near fracture, the surface roughness in singled-out zones) and the damage parameters (the sizes of pits and the pitting area) are evaluated.

  7. Influence of surface position along the working range of conoscopic holography sensors on dimensional verification of AISI 316 wire EDM machined surfaces.

    Science.gov (United States)

    Fernández, Pedro; Blanco, David; Rico, Carlos; Valiño, Gonzalo; Mateos, Sabino

    2014-03-06

    Conoscopic holography (CH) is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F) and power (P) until the quality indicators Signal-to-Noise Ratio (SNR) and signal envelope (Total) meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR). Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP) on a CMM.

  8. Influence of Surface Position along the Working Range of Conoscopic Holography Sensors on Dimensional Verification of AISI 316 Wire EDM Machined Surfaces

    Directory of Open Access Journals (Sweden)

    Pedro Fernández

    2014-03-01

    Full Text Available Conoscopic holography (CH is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F and power (P until the quality indicators Signal-to-Noise Ratio (SNR and signal envelope (Total meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR. Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP on a CMM.

  9. The effect of TWD estimation error on the geometry of machined surfaces in micro-EDM milling

    DEFF Research Database (Denmark)

    Puthumana, Govindan; Bissacco, Giuliano; Hansen, Hans Nørgaard

    In micro EDM (electrical discharge machining) milling, tool electrode wear must be effectively compensated in order to achieve high accuracy of machined features [1]. Tool wear compensation in micro-EDM milling can be based on off-line techniques with limited accuracy such as estimation...... and statistical characterization of the discharge population [3]. The TWD based approach permits the direct control of the position of the tool electrode front surface. However, TWD estimation errors will generate a self-amplifying error on the tool electrode axial depth during micro-EDM milling. Therefore....... The error propagation effect is demonstrated through a software simulation tool developed by the authors for determination of the correct TWD for subsequent use in compensation of electrode wear in EDM milling. The implemented model uses an initial arbitrary estimation of TWD and a single experiment...

  10. Learning Activity Packets for Grinding Machines. Unit II--Surface Grinding.

    Science.gov (United States)

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the second unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  11. Application of surface activation of machine elements in a cyclotron aiming at tribological diagnostics

    International Nuclear Information System (INIS)

    Kosinova, M.

    1989-01-01

    The results of estimation of wear of machine elements using their activation with charged particles accelerated in the cyclotron are presented. The results of bench tests are given. It is shown that wear of sleeves, hominged with plateau formation, is twice less than that of sleeves hominged in a standard way. 7 refs.; 3 figs

  12. A Study of Resin as Master Jewellery Material, Surface Quality and Machining Time Improvement by Implementing Appropriate Cutting Strategy

    Directory of Open Access Journals (Sweden)

    Puspaputra Paryana

    2017-01-01

    Full Text Available This paper deals with a research about art and jewellery product machining that focused in the selection of appropriate material for jewellery master which is machined by CNC. CNC is used for better surface finish for no undercut design and more complex ornament. The need of production speed requires minimum process without reducing the quality of detail ornament significantly. Problems occur when high surface quality is required. In that condition high speed spindle is used with low feeding speed, as a result is high temperature in cutter-material area will melt the resin and build the build-up edge (BUE. Due to the existence of BUE, the cutting tool will no longer cut the resin, as a result the resin will then melt due to friction and the melt resin will then stuck on the relief and surface finish become worst and rework should be done. When required surface is achieved problem also occur in next going process, that is silicon mould making. Due to galvanization process for silicon at about 170°C, resin material may be broken or cracked. Research is then conducted to select appropriate resin type suitable for all production steps.

  13. A new optimization tool path planning for 3-axis end milling of free-form surfaces based on efficient machining intervals

    Science.gov (United States)

    Vu, Duy-Duc; Monies, Frédéric; Rubio, Walter

    2018-05-01

    A large number of studies, based on 3-axis end milling of free-form surfaces, seek to optimize tool path planning. Approaches try to optimize the machining time by reducing the total tool path length while respecting the criterion of the maximum scallop height. Theoretically, the tool path trajectories that remove the most material follow the directions in which the machined width is the largest. The free-form surface is often considered as a single machining area. Therefore, the optimization on the entire surface is limited. Indeed, it is difficult to define tool trajectories with optimal feed directions which generate largest machined widths. Another limiting point of previous approaches for effectively reduce machining time is the inadequate choice of the tool. Researchers use generally a spherical tool on the entire surface. However, the gains proposed by these different methods developed with these tools lead to relatively small time savings. Therefore, this study proposes a new method, using toroidal milling tools, for generating toolpaths in different regions on the machining surface. The surface is divided into several regions based on machining intervals. These intervals ensure that the effective radius of the tool, at each cutter-contact points on the surface, is always greater than the radius of the tool in an optimized feed direction. A parallel plane strategy is then used on the sub-surfaces with an optimal specific feed direction for each sub-surface. This method allows one to mill the entire surface with efficiency greater than with the use of a spherical tool. The proposed method is calculated and modeled using Maple software to find optimal regions and feed directions in each region. This new method is tested on a free-form surface. A comparison is made with a spherical cutter to show the significant gains obtained with a toroidal milling cutter. Comparisons with CAM software and experimental validations are also done. The results show the

  14. INFLUENCE OF MICRO-SEGREGATION IN PB-S-ALLOYED FREE MACHINING STEELS ON THE SURFACE QUALITY OF THE ROLLED WIRE-ROD

    OpenAIRE

    Leuschke, U.; Rajesh Puvvada, N.; Puvvada, Rajesh

    2008-01-01

    Free machining steel billets were manufactured at the continuous casting machine. The manufactured billets did not exhibit any kind of surface defects but surface cracks and slivers appeared when the billets were rolled into wires and rods at the wire-rod mill. The defects on rolled wire-rod have been detected by a hot eddy current system. Further investigations in these defects with the help of microprobe analysis system and scanning electron microscope equipped with image analysis system re...

  15. Synthesis of Silicalite Membrane with an Aluminum-Containing Surface for Controlled Modification of Zeolitic Pore Entries for Enhanced Gas Separation

    Directory of Open Access Journals (Sweden)

    Shaowei Yang

    2018-02-01

    Full Text Available The separation of small molecule gases by membrane technologies can help performance enhancement and process intensification for emerging advanced fossil energy systems with CO2 capture capacity. This paper reports the demonstration of controlled modification of zeolitic channel size for the MFI-type zeolite membranes to enhance the separation of small molecule gases such as O2 and N2. Pure-silica MFI-type zeolite membranes were synthesized on porous α-alumina disc substrates with and without an aluminum-containing thin skin on the outer surface of zeolite membrane. The membranes were subsequently modified by on-stream catalytic cracking deposition (CCD of molecular silica to reduce the effective openings of the zeolitic channels. Such a pore modification caused the transition of gas permeation from the N2-selective gaseous diffusion mechanism in the pristine membrane to the O2-selective activated diffusion mechanism in the modified membrane. The experimental results indicated that the pore modification could be effectively limited within the aluminum-containing surface of the MFI zeolite membrane to minimize the mass transport resistance for O2 permeation while maintaining its selectivity. The implications of pore modification on the size-exclusion-enabled gas selectivity were discussed based on the kinetic molecular theory. In light of the theoretical analysis, experimental investigation was performed to further enhance the membrane separation selectivity by chemical liquid deposition of silica into the undesirable intercrystalline spaces.

  16. Growth of porous anodized alumina on the sputtered aluminum films with 2D-3D morphology for high specific surface area

    Science.gov (United States)

    Liao, M. W.; Chung, C. K.

    2014-08-01

    The porous anodic aluminum oxide (AAO) with high-aspect-ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional (1D) nanostructures. The high specific surface area of AAO can also be applied to the super capacitor and the supporting substrate for catalysis. The rough surface could be helpful to enhance specific surface area but it generally results in electrical field concentration even to ruin AAO. In this article, the aluminum (Al) films with the varied 2D-3D morphology on Si substrates were prepared using magnetron sputtering at a power of 50 W-185 W for 1 h at a working pressure of 2.5 × 10-1 Pa. Then, AAO was fabricated from the different Al films by means of one-step hybrid pulse anodizing (HPA) between the positive 40 V and the negative -2 V (1 s:1 s) for 3 min in 0.3 M oxalic acid at a room temperature. The microstructure and morphology of Al films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscope, respectively. Some hillocks formed at the high target power could be attributed to the grain texture growth in the normal orientation of Al(1 1 1). The 3D porous AAO structure which is different from the conventional 2D planar one has been successfully demonstrated using HPA on the film with greatly rough hillock-surface formed at the highest power of 185 W. It offers a potential application of the new 3D AAO to high specific surface area devices.

  17. Growth of porous anodized alumina on the sputtered aluminum films with 2D–3D morphology for high specific surface area

    Energy Technology Data Exchange (ETDEWEB)

    Liao, M.W.; Chung, C.K., E-mail: ckchung@mail.ncku.edu.tw

    2014-08-01

    The porous anodic aluminum oxide (AAO) with high-aspect-ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional (1D) nanostructures. The high specific surface area of AAO can also be applied to the super capacitor and the supporting substrate for catalysis. The rough surface could be helpful to enhance specific surface area but it generally results in electrical field concentration even to ruin AAO. In this article, the aluminum (Al) films with the varied 2D–3D morphology on Si substrates were prepared using magnetron sputtering at a power of 50 W–185 W for 1 h at a working pressure of 2.5 × 10⁻¹ Pa. Then, AAO was fabricated from the different Al films by means of one-step hybrid pulse anodizing (HPA) between the positive 40 V and the negative -2 V (1 s:1 s) for 3 min in 0.3 M oxalic acid at a room temperature. The microstructure and morphology of Al films were characterized by X-ray diffraction, scanning electron microscope and atomic force microscope, respectively. Some hillocks formed at the high target power could be attributed to the grain texture growth in the normal orientation of Al(1 1 1). The 3D porous AAO structure which is different from the conventional 2D planar one has been successfully demonstrated using HPA on the film with greatly rough hillock-surface formed at the highest power of 185 W. It offers a potential application of the new 3D AAO to high specific surface area devices.

  18. Estimation of Surface Soil Moisture in Irrigated Lands by Assimilation of Landsat Vegetation Indices, Surface Energy Balance Products, and Relevance Vector Machines

    Directory of Open Access Journals (Sweden)

    Alfonso F. Torres-Rua

    2016-04-01

    Full Text Available Spatial surface soil moisture can be an important indicator of crop conditions on farmland, but its continuous estimation remains challenging due to coarse spatial and temporal resolution of existing remotely-sensed products. Furthermore, while preceding research on soil moisture using remote sensing (surface energy balance, weather parameters, and vegetation indices has demonstrated a relationship between these factors and soil moisture, practical continuous spatial quantification of the latter is still unavailable for use in water and agricultural management. In this study, a methodology is presented to estimate volumetric surface soil moisture by statistical selection from potential predictors that include vegetation indices and energy balance products derived from satellite (Landsat imagery and weather data as identified in scientific literature. This methodology employs a statistical learning machine called a Relevance Vector Machine (RVM to identify and relate the potential predictors to soil moisture by means of stratified cross-validation and forward variable selection. Surface soil moisture measurements from irrigated agricultural fields in Central Utah in the 2012 irrigation season were used, along with weather data, Landsat vegetation indices, and energy balance products. The methodology, data collection, processing, and estimation accuracy are presented and discussed.

  19. Machining the Integral Impeller and Blisk of Aero-Engines: A Review of Surface Finishing and Strengthening Technologies

    Science.gov (United States)

    Fu, Youzhi; Gao, Hang; Wang, Xuanping; Guo, Dongming

    2017-05-01

    The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has significant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and integrated finishing and strengthening technologies and discusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.

  20. Online Surface Defect Identification of Cold Rolled Strips Based on Local Binary Pattern and Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2018-03-01

    Full Text Available In the production of cold-rolled strip, the strip surface may suffer from various defects which need to be detected and identified using an online inspection system. The system is equipped with high-speed and high-resolution cameras to acquire images from the moving strip surface. Features are then extracted from the images and are used as inputs of a pre-trained classifier to identify the type of defect. New types of defect often appear in production. At this point the pre-trained classifier needs to be quickly retrained and deployed in seconds to meet the requirement of the online identification of all defects in the environment of a continuous production line. Therefore, the method for extracting the image features and the training for the classification model should be automated and fast enough, normally within seconds. This paper presents our findings in investigating the computational and classification performance of various feature extraction methods and classification models for the strip surface defect identification. The methods include Scale Invariant Feature Transform (SIFT, Speeded Up Robust Features (SURF and Local Binary Patterns (LBP. The classifiers we have assessed include Back Propagation (BP neural network, Support Vector Machine (SVM and Extreme Learning Machine (ELM. By comparing various combinations of different feature extraction and classification methods, our experiments show that the hybrid method of LBP for feature extraction and ELM for defect classification results in less training and identification time with higher classification accuracy, which satisfied online real-time identification.

  1. On-machine measurement of the grinding wheels' 3D surface topography using a laser displacement sensor

    Science.gov (United States)

    Pan, Yongcheng; Zhao, Qingliang; Guo, Bing

    2014-08-01

    A method of non-contact, on-machine measurement of three dimensional surface topography of grinding wheels' whole surface was developed in this paper, focusing on an electroplated coarse-grained diamond grinding wheel. The measuring system consists of a Keyence laser displacement sensor, a Keyence controller and a NI PCI-6132 data acquisition card. A resolution of 0.1μm in vertical direction and 8μm in horizontal direction could be achieved. After processing the data by LabVIEW and MATLAB, the 3D topography of the grinding wheel's whole surface could be reconstructed. When comparing the reconstructed 3D topography of the grinding wheel's marked area to its real topography captured by a high-depth-field optical digital microscope (HDF-ODM) and scanning electron microscope (SEM), they were very similar to each other, proving that this method is accurate and effective. By a subsequent data processing, the topography of every grain could be extracted and then the active grain number, the active grain volume and the active grain's bearing ration could be calculated. These three parameters could serve as the criterion to evaluate the grinding performance of coarse-grained diamond grinding wheels. Then the performance of the grinding wheel could be evaluated on-machine accurately and quantitatively.

  2. Optimization of GMAW process of AA 6063-T5 aluminum alloy butt joints based on the response surface methodology and on the bead geometry

    International Nuclear Information System (INIS)

    Miguel, V.; Martinez-Conesa, E. J.; Segura, F.; Manjabacas, M. C.; Abellan, E.

    2012-01-01

    The geometry of the weld beads is characterized by the overhead, the width and the penetration. These values are indices of the behavior of the welded joint and therefore, they can be considered as factors that control the process. This work is performed to optimize the GMAW process of the aluminum alloy AA 6063-T5 by means of the response surface methodology (RSM). The variables herein considered are the arc voltage, the welding speed, the wire feed speed and the separation between surfaces in butt joints. The response functions that are herein studied are the overhead, the width, the penetration and the angle of the bead. The obtained results by RSM show high grade of agreement with the experimental values. The procedure is experimentally validated by welding for the theoretically obtained optimized technological conditions and a wide agreement between theoretical and experimental values is found. (Author) 16 refs.

  3. Helium trapping in aluminum and sintered aluminum powders

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminsky, M.; Rossing, T.

    1975-01-01

    The surface erosion of annealed aluminum and of sintered aluminum powder (SAP) due to blistering from implantation of 100-keV 4 He + ions at room temperature has been investigated. A substantial reduction in the blistering erosion rate in SAP was observed from that in pure annealed aluminum. In order to determine whether the observed reduction in blistering is due to enhanced helium trapping or due to helium released, the implanted helium profiles in annealed aluminum and in SAP have been studied by Rutherford backscattering. The results show that more helium is trapped in SAP than in aluminum for identical irradiation conditions. The observed reduction in erosion from helium blistering in SAP is more likely due to the dispersion of trapped helium at the large Al-Al 2 O 3 interfaces and at the large grain boundaries in SAP than to helium release

  4. Surface mechanical property and residual stress of peened nickel-aluminum bronze determined by in-situ X-ray diffraction

    Science.gov (United States)

    Wang, Chengxi; Jiang, Chuanhai; Zhao, Yuantao; Chen, Ming; Ji, Vincent

    2017-10-01

    As one of the most important surface strengthening method, shot peening is widely used to improve the fatigue and stress corrosion crack resistance of components by introducing the refined microstructure and compressive residual stress in the surface layer. However, the mechanical properties of this thin layer are different from the base metal and are difficult to be characterized by conventional techniques. In this work, a micro uniaxial tensile tester equipped with in-situ X-ray stress analyzer was employed to make it achievable on a nickel-aluminum bronze with shot peening treatment. According to the equivalent stress-strain relationship based on Von Mises stress criterion, the Young's modulus and yield strength of the peened layer were calculated. The results showed that the Young's modulus was the same as the bulk material, and the yield strength corresponding to the permanent plastic strain of 0.2% was increased by 21% after SP. But the fractographic analysis showed that the fracture feature of the surface layer was likely to transform from the dimple to the cleavage, indicating the improved strength might be attained at the expense of ductility. The monotonic and cyclic loading were also performed via the same combined set-up. In addition, the specific relaxation behavior of compressive residual stress was quantified by linear logarithm relationship between residual stress and cycle numbers. It was found that the compressive residual stress mainly relaxed in the first few cycles, and then reached steady state with further cycles. The relaxation rate and the stable value were chiefly depended on the stress amplitude and number of cycles. The retained residual stress kept in compressive under all given applied stress levels, suggesting that the shot peening could introduce a more stable surface layer of compressive residual stress other than the elevated strength of nickel-aluminum bronze alloy.

  5. Evolution of the thickness of the aluminum oxide film due to the pH of the cooling water and surface temperature of the fuel elements clad of a nuclear reactor

    International Nuclear Information System (INIS)

    Babiche, Ivan

    2013-01-01

    This paper describes the mechanism of growth of a film of aluminum oxide on an alloy of the same material, which serves as a protective surface being the constituent material of the RP-10 nuclear reactor fuel elements clads. The most influential parameters on the growth of this film are: the pH of the cooling water and the clad surface temperature of the fuel element. For this study, a mathematical model relating the evolution of the aluminum oxide layer thickness over the time, according to the same oxide film using a power law is used. It is concluded that the time of irradiation, the heat flux at the surface of the aluminum material, the speed of the coolant, the thermal conductivity of the oxide, the initial thickness of the oxide layer and the solubility of the protective oxide are parameters affecting in the rate and film formation. (author).

  6. Uniform superhydrophobic surfaces using micro/nano complex structures formed spontaneously by a simple and cost-effective nonlithographic process based on anodic aluminum oxide technology

    International Nuclear Information System (INIS)

    Kim, Dae-Ho; Cho, Chae-Ryong; Kim, Jong-Man; Kim, Yongsung; Kim, Byung Min; Ko, Jong Soo

    2011-01-01

    This paper presents a uniform micro/nano double-roughened superhydrophobic surface with a high static contact angle (CA) and low contact angle hysteresis (CAH). The proposed micro/nano complex structured surfaces were self-fabricated simply and efficiently using a very simple and low-cost nonlithographic sequential process, which consists of aluminum (Al) sputtering, anodization of the Al layer and pore widening, without specific equipment and additional subsequent processes. The wetting properties of the fabricated surfaces were characterized by measuring the static CAs and the CAHs after plasma polymerized fluorocarbon coating with a low surface energy. The measured static CA and CAH were 154 ± 2.3° and 5.7 ± 0.8°, respectively, showing that the fabricated double-roughened surfaces exhibit superhydrophobic behaviors clearly. In addition, the proposed double-scaled surfaces at a wafer-level exhibited uniform superhydrophobic behaviors across the wafer with an apparent CA and CAH of 153.9 ± 0.8° and 4.9 ± 1.3°, respectively.

  7. Evaluation of Surface Roughness by Image Processing of a Shot-Peened, TIG-Welded Aluminum 6061-T6 Alloy: An Experimental Case Study

    Directory of Open Access Journals (Sweden)

    Anas M. Atieh

    2018-05-01

    Full Text Available Visual inspection through image processing of welding and shot-peened surfaces is necessary to overcome equipment limitations, avoid measurement errors, and accelerate processing to gain certain surface properties such as surface roughness. Therefore, it is important to design an algorithm to quantify surface properties, which enables us to overcome the aforementioned limitations. In this study, a proposed systematic algorithm is utilized to generate and compare the surface roughness of Tungsten Inert Gas (TIG welded aluminum 6061-T6 alloy treated by two levels of shot-peening, high-intensity and low-intensity. This project is industrial in nature, and the proposed solution was originally requested by local industry to overcome equipment capabilities and limitations. In particular, surface roughness measurements are usually only possible on flat surfaces but not on other areas treated by shot-peening after welding, as in the heat-affected zone and weld beads. Therefore, those critical areas are outside of the measurement limitations. Using the proposed technique, the surface roughness measurements were possible to obtain for weld beads, high-intensity and low-intensity shot-peened surfaces. In addition, a 3D surface topography was generated and dimple size distributions were calculated for the three tested scenarios: control sample (TIG-welded only, high-intensity shot-peened, and low-intensity shot-peened TIG-welded Al6065-T6 samples. Finally, cross-sectional hardness profiles were measured for the three scenarios; in all scenarios, lower hardness measurements were obtained compared to the base metal alloy in the heat-affected zone and in the weld beads even after shot-peening treatments.

  8. 3–10 keV Xe+ ion beam machining of ultra low thermal expansion glasses for EUVL projection optics: Evaluation of surface roughness

    International Nuclear Information System (INIS)

    Morikawa, K.; Kamijo, K.; Morijiri, K.; Pahlovy, S.A.; Aikawa, N.; Miyamoto, I.

    2012-01-01

    In order to obtain surface figure error of 0.15 nm rms and surface roughness (R rms ) of 0.12 nm rms for aspherical substrates in EUVL tools, ion beam figuring may be adopted to final surface figure error correction of aspherical substrates. During figure error correction, machined surface of the substrate becomes rougher than the pre-finished one. Therefore, we investigated the machined depth and ion energy dependences of R rms (measured by an AFM) of substrates machined by 3–10 keV Xe + ion beam, and compared them with the results obtained for Ar + ion beam. Result shows that the R rms s of CLEARCERAM®-Z, Zerodur® and ULE® substrates machined to the depth of 50 nm by 3–10 keV Xe + ion beam at the normal ion incidence angle become approximately 0.25, 0.28 and 0.15 nm rms, respectively. Those values are larger than the pre-finished substrates (0.07–0.09 nm rms), but smaller than that (0.60 nm rms for CLEARCERAM®-Z, 0.61 nm rms for Zerodur® and 0.18 nm rms for ULE®) of the substrates machined by Ar + ion beam. Moreover, the R rms s merely increase with increasing ion energy. The R rms s of the ULE® substrate machined by 3–10 keV Xe + ion beam rapidly increase with increasing machined depth, then saturate at machined depth of 10–50 nm. The saturated values of the R rms s are 0.12 and 0.15 nm rms for 3 and 10 keV Xe + ion beam respectively. We suggest that the 3 keV Xe + ion beam machining can be applicable for final shape correction of ULE® substrates for EUVL projection optics in association with considering further ultra smoothing process such as Si deposition or low energy ion beam smoothing.

  9. Detection of surface cracking in steel pipes based on vibration data using a multi-class support vector machine classifier

    Science.gov (United States)

    Mustapha, S.; Braytee, A.; Ye, L.

    2017-04-01

    In this study, we focused at the development and verification of a robust framework for surface crack detection in steel pipes using measured vibration responses; with the presence of multiple progressive damage occurring in different locations within the structure. Feature selection, dimensionality reduction, and multi-class support vector machine were established for this purpose. Nine damage cases, at different locations, orientations and length, were introduced into the pipe structure. The pipe was impacted 300 times using an impact hammer, after each damage case, the vibration data were collected using 3 PZT wafers which were installed on the outer surface of the pipe. At first, damage sensitive features were extracted using the frequency response function approach followed by recursive feature elimination for dimensionality reduction. Then, a multi-class support vector machine learning algorithm was employed to train the data and generate a statistical model. Once the model is established, decision values and distances from the hyper-plane were generated for the new collected data using the trained model. This process was repeated on the data collected from each sensor. Overall, using a single sensor for training and testing led to a very high accuracy reaching 98% in the assessment of the 9 damage cases used in this study.

  10. Experimental and Numerical Study of the Influence of Substrate Surface Preparation on Adhesion Mechanisms of Aluminum Cold Spray Coatings on 300M Steel Substrates

    Science.gov (United States)

    Nastic, A.; Vijay, M.; Tieu, A.; Rahmati, S.; Jodoin, B.

    2017-10-01

    The effect of substrate surface topography on the creation of metallurgical bonds and mechanical anchoring points has been studied for the cold spray deposition of pure aluminum on 300M steel substrate material. The coatings adhesion strength showed a significant decrease from 31.0 ± 5.7 MPa on polished substrates to 6.9 ± 2.0 MPa for substrates with roughness of 2.2 ± 0.5 μm. Strengths in the vicinity of 45 MPa were reached for coatings deposited onto forced pulsed waterjet treated surfaces with roughnesses larger than 33.8 μm. Finite element analysis has confirmed the sole presence of mechanical anchoring in coating adhesion strength for all surface treatment except polished surfaces. Grit embedment has been shown to be non-detrimental to coating adhesion for the current deposited material combination. The particle deformation process during impacts has been studied through finite element analysis using the Preston-Tonks-Wallace (PTW) constitutive model. The obtained equivalent plastic strain (PEEQ), temperature, contact pressure and velocity vector were correlated to the particle ability to form metallurgical bonds. Favorable conditions for metallurgical bonding were found to be highest for particles deposited on polished substrates, as confirmed by fracture surface analysis.

  11. Study of surface integrity AISI 4140 as result of hard, dry and high speed machining using CBN

    Science.gov (United States)

    Ginting, B.; Sembiring, R. W.; Manurung, N.

    2017-09-01

    The concept of hard, dry and high speed machining can be combined, to produce high productivity, with lower production costs in manufacturing industry. Hard lathe process can be a solution to reduce production time. In lathe hard alloy steels reported problems relating to the integrity of such surface roughness, residual stress, the white layer and the surface integrity. AISI 4140 material is used for high reliable hydraulic system components. This material includes in cold work tool steel. Consideration election is because this material is able to be hardened up to 55 HRC. In this research, the experimental design using CCD model fit with three factors, each factor is composed of two levels, and six central point, experiments were conducted with 1 replications. The experimental design research using CCD model fit.

  12. Predictive Models for Different Roughness Parameters During Machining Process of Peek Composites Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Mata-Cabrera Francisco

    2013-10-01

    Full Text Available Polyetheretherketone (PEEK composite belongs to a group of high performance thermoplastic polymers and is widely used in structural components. To improve the mechanical and tribological properties, short fibers are added as reinforcement to the material. Due to its functional properties and potential applications, it’s impor- tant to investigate the machinability of non-reinforced PEEK (PEEK, PEEK rein- forced with 30% of carbon fibers (PEEK CF30, and reinforced PEEK with 30% glass fibers (PEEK GF30 to determine the optimal conditions for the manufacture of the parts. The present study establishes the relationship between the cutting con- ditions (cutting speed and feed rate and the roughness (Ra , Rt , Rq , Rp , by develop- ing second order mathematical models. The experiments were planned as per full factorial design of experiments and an analysis of variance has been performed to check the adequacy of the models. These state the adequacy of the derived models to obtain predictions for roughness parameters within ranges of parameters that have been investigated during the experiments. The experimental results show that the most influence of the cutting parameters is the feed rate, furthermore, proved that glass fiber reinforcements produce a worse machinability.

  13. Minimization of energy and surface roughness of the products machined by milling

    Science.gov (United States)

    Belloufi, A.; Abdelkrim, M.; Bouakba, M.; Rezgui, I.

    2017-08-01

    Metal cutting represents a large portion in the manufacturing industries, which makes this process the largest consumer of energy. Energy consumption is an indirect source of carbon footprint, we know that CO2 emissions come from the production of energy. Therefore high energy consumption requires a large production, which leads to high cost and a large amount of CO2 emissions. At this day, a lot of researches done on the Metal cutting, but the environmental problems of the processes are rarely discussed. The right selection of cutting parameters is an effective method to reduce energy consumption because of the direct relationship between energy consumption and cutting parameters in machining processes. Therefore, one of the objectives of this research is to propose an optimization strategy suitable for machining processes (milling) to achieve the optimum cutting conditions based on the criterion of the energy consumed during the milling. In this paper the problem of energy consumed in milling is solved by an optimization method chosen. The optimization is done according to the different requirements in the process of roughing and finishing under various technological constraints.

  14. X-ray spectrum microanalysis of copper and stainless steel surface layer after electroerosion machining

    International Nuclear Information System (INIS)

    Abdukarimov, Eh.T.; Saidinov, S.Ya.

    1989-01-01

    The results of experimental investigations of the surface layer of copper and steel 12Kh18N10T after electroerrosion treatment by a rotating tungsten electrode in natural and distilled water are presented. It is established that the quantity of electrode material transferred to the surface of the steel treated grows with the spark discharge energy increase. Tungsten concentration in the surface layer reaches 5-10% with the average depth of penetration 40-50 μm

  15. Effect of oxide film formation on the fatigue behavior of aluminum alloy

    International Nuclear Information System (INIS)

    Kim, Jong Cheon; Cheong, Seong Kyun

    2012-01-01

    In this study, the effects of surface oxide film formation on the fatigue behavior of 7075-T6 aluminum alloy were analyzed in terms of the corrosion time of the alloy. The aluminum material used is known to have high corrosion resistance due to the passivation phenomenon that prevents corrosion. Aluminum alloys have been widely used in various industrial applications such as aircraft component manufacturing because of their lighter weight and higher strength than other materials. Therefore, studies on the fatigue behavior of materials and passivation properties that prevent corrosion are required. The fatigue behavior in terms of the corrosion time was analyzed by using a four pointing bending machine, and the surface corrosion level of the aluminum material in terms of the corrosion time was estimated by measuring the surface were studied by scanning electron microscopy (SEM). The results indicated that corrosion actively progressed for four weeks during the initial corrosion phase, the fatigue life significantly decreased, and the surface roughness increased. However, after four weeks, the corrosion reaction tended to slow down due to the passivation phenomenon of the material. Therefore, on the basis of SEM analysis results, it was concluded that the growth of the surface oxide film was reduced after four weeks and then the oxide film on the material surface served as a protection layer and prevented further corrosion

  16. Machining with abrasives

    CERN Document Server

    Jackson, Mark J

    2011-01-01

    Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.

  17. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source.

    Science.gov (United States)

    Venkatesan, K

    2017-07-01

    Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60-150 m/min, feed rates of 0.05-0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  18. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source

    Directory of Open Access Journals (Sweden)

    K. Venkatesan

    2017-07-01

    Full Text Available Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60–150 m/min, feed rates of 0.05–0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  19. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  20. Dewetting of polymer thin films on modified curved surfaces: preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates.

    Science.gov (United States)

    Liu, Chih-Ting; Tsai, Chia-Chan; Chu, Chien-Wei; Chi, Mu-Huan; Chung, Pei-Yun; Chen, Jiun-Tai

    2018-04-18

    We study the dewetting behaviors of poly(methyl methacrylate) (PMMA) thin films coated in the cylindrical nanopores of anodic aluminum oxide (AAO) templates by thermal annealing. Self-assembled monolayers (SAMs) of n-octadecyltrichlorosilane (ODTS) are introduced to modify the pore surfaces of the AAO templates to induce the dewetting process. By using scanning electron microscopy (SEM), the dewetting-induced morphology transformation from the PMMA thin films to PMMA nanoparticles with asymmetric shapes can be observed. The sizes of the PMMA nanoparticles can be controlled by the original PMMA solution concentrations. The dewetting phenomena on the modified nanopores are explained by taking into account the excess intermolecular interaction free energy (ΔG). This work opens a new possibility for creating polymer nanoparticles with asymmetric shapes in confined geometries.

  1. Wear-triggered self-healing behavior on the surface of nanocrystalline nickel aluminum bronze/Ti3SiC2 composites

    Science.gov (United States)

    Zhai, Wenzheng; Lu, Wenlong; Zhang, Po; Wang, Jian; Liu, Xiaojun; Zhou, Liping

    2018-04-01

    Self-healing can protect materials from diverse damages, but is intrinsically difficult in metals. This paper demonstrates a potential method through a simultaneous decomposition and oxidation of Ti3SiC2 to achieve healing of stress cracking on the surface of nickel aluminum bronze (NAB)/Ti3SiC2 nanocrystalline composites during fretting wear. At the finest nanocrystalline materials, a crack recovery would be attained at 76.5%. The repetitive fretting wear leads to a modest amount of 'flowability' of Ti3SiC2 toward the crack, facilitating crack recovery. Along with the wear-triggered self-healing, the NAB/Ti3SiC2 shows an improved tribological performance with the stable decreased friction torque due to the formation of lubrication TiO2 oxide.

  2. Study of the effect of PH, surface finish and thermal treatment on the corrosion of AlFeNi aluminum alloy

    International Nuclear Information System (INIS)

    Nabhan, Diana

    2013-01-01

    The Jules Horowitz Reactor (JHR) is a research reactor under construction at the CEA Cadarache research center, France. It is scheduled to start operating by 2020. The fuel elements of this reactor core consist of eight concentric rows of cylindrical plates, each row being composed of three thin aluminum coated plates. Cooling water circulates between these plates through very thin gaps smaller than 2 mm. The aluminum alloy used to coat the fuel plates is an alloy called AlFeNi, which contains 1% wt. Fe, 1% wt. Ni and 1% wt. Mg. In the reactor environment, this alloy may undergo corrosion. The oxide layer formed on the AlFeNi alloy is composed of two different types of oxides: an inner oxide layer formed by a diffusion mechanism and an outer oxide layer formed by re-precipitation. As a consequence, formation of an oxide scale on the aluminum coating could reduce the gap between the cladding plates, thus allowing less water to circulate. This could in turn lead to local heating of the fuel cladding. In addition, the metal consumption and the softening of the metal at high temperatures can lead to a decrease of the mechanical strength of the cladding. In order to qualify the fuel elements of the JHR, several specimens of AlFeNi, representative of the future cladding, were corroded at 250 .deg. C for different durations (9 to 34 days) in distilled water of different pH: 4.9; 5.2 and 5.6. These pH values have been chosen to simulate the ones currently predicted for the JHR. The effect of surface finish (polished and not polished) and thermal treatment (annealed and not annealed) on the oxide growth rate was also investigated. For long tests over 30 days, the pH 5,6 appears to be more favorable than the pH 5,2 and 4,9 to limit the oxide thickness, but this pH effect is reduced on unpolished samples. In one hand, the effect of surface finish on the corrosion behavior as measured by optical microscopy appears to be strong. On the other hand, the effect of thermal

  3. Study of the effect of PH, surface finish and thermal treatment on the corrosion of AlFeNi aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nabhan, Diana [Comissariat a l' Energie Atomique, Paris (France)

    2013-07-01

    The Jules Horowitz Reactor (JHR) is a research reactor under construction at the CEA Cadarache research center, France. It is scheduled to start operating by 2020. The fuel elements of this reactor core consist of eight concentric rows of cylindrical plates, each row being composed of three thin aluminum coated plates. Cooling water circulates between these plates through very thin gaps smaller than 2 mm. The aluminum alloy used to coat the fuel plates is an alloy called AlFeNi, which contains 1% wt. Fe, 1% wt. Ni and 1% wt. Mg. In the reactor environment, this alloy may undergo corrosion. The oxide layer formed on the AlFeNi alloy is composed of two different types of oxides: an inner oxide layer formed by a diffusion mechanism and an outer oxide layer formed by re-precipitation. As a consequence, formation of an oxide scale on the aluminum coating could reduce the gap between the cladding plates, thus allowing less water to circulate. This could in turn lead to local heating of the fuel cladding. In addition, the metal consumption and the softening of the metal at high temperatures can lead to a decrease of the mechanical strength of the cladding. In order to qualify the fuel elements of the JHR, several specimens of AlFeNi, representative of the future cladding, were corroded at 250 .deg. C for different durations (9 to 34 days) in distilled water of different pH: 4.9; 5.2 and 5.6. These pH values have been chosen to simulate the ones currently predicted for the JHR. The effect of surface finish (polished and not polished) and thermal treatment (annealed and not annealed) on the oxide growth rate was also investigated. For long tests over 30 days, the pH 5,6 appears to be more favorable than the pH 5,2 and 4,9 to limit the oxide thickness, but this pH effect is reduced on unpolished samples. In one hand, the effect of surface finish on the corrosion behavior as measured by optical microscopy appears to be strong. On the other hand, the effect of thermal

  4. Control of deviations and prediction of surface roughness from micro machining of THz waveguides using acoustic emission signals

    Science.gov (United States)

    Griffin, James M.; Diaz, Fernanda; Geerling, Edgar; Clasing, Matias; Ponce, Vicente; Taylor, Chris; Turner, Sam; Michael, Ernest A.; Patricio Mena, F.; Bronfman, Leonardo

    2017-02-01

    By using acoustic emission (AE) it is possible to control deviations and surface quality during micro milling operations. The method of micro milling is used to manufacture a submillimetre waveguide where micro machining is employed to achieve the required superior finish and geometrical tolerances. Submillimetre waveguide technology is used in deep space signal retrieval where highest detection efficiencies are needed and therefore every possible signal loss in the receiver has to be avoided and stringent tolerances achieved. With a sub-standard surface finish the signals travelling along the waveguides dissipate away faster than with perfect surfaces where the residual roughness becomes comparable with the electromagnetic skin depth. Therefore, the higher the radio frequency the more critical this becomes. The method of time-frequency analysis (STFT) is used to transfer raw AE into more meaningful salient signal features (SF). This information was then correlated against the measured geometrical deviations and, the onset of catastrophic tool wear. Such deviations can be offset from different AE signals (different deviations from subsequent tests) and feedback for a final spring cut ensuring the geometrical accuracies are met. Geometrical differences can impact on the required transfer of AE signals (change in cut off frequencies and diminished SNR at the interface) and therefore errors have to be minimised to within 1 μm. Rules based on both Classification and Regression Trees (CART) and Neural Networks (NN) were used to implement a simulation displaying how such a control regime could be used as a real time controller, be it corrective measures (via spring cuts) over several initial machining passes or, with a micron cut introducing a level plain measure for allowing setup corrective measures (similar to a spirit level).

  5. Surface electromyography based muscle fatigue detection using high-resolution time-frequency methods and machine learning algorithms.

    Science.gov (United States)

    Karthick, P A; Ghosh, Diptasree Maitra; Ramakrishnan, S

    2018-02-01

    Surface electromyography (sEMG) based muscle fatigue research is widely preferred in sports science and occupational/rehabilitation studies due to its noninvasiveness. However, these signals are complex, multicomponent and highly nonstationary with large inter-subject variations, particularly during dynamic contractions. Hence, time-frequency based machine learning methodologies can improve the design of automated system for these signals. In this work, the analysis based on high-resolution time-frequency methods, namely, Stockwell transform (S-transform), B-distribution (BD) and extended modified B-distribution (EMBD) are proposed to differentiate the dynamic muscle nonfatigue and fatigue conditions. The nonfatigue and fatigue segments of sEMG signals recorded from the biceps brachii of 52 healthy volunteers are preprocessed and subjected to S-transform, BD and EMBD. Twelve features are extracted from each method and prominent features are selected using genetic algorithm (GA) and binary particle swarm optimization (BPSO). Five machine learning algorithms, namely, naïve Bayes, support vector machine (SVM) of polynomial and radial basis kernel, random forest and rotation forests are used for the classification. The results show that all the proposed time-frequency distributions (TFDs) are able to show the nonstationary variations of sEMG signals. Most of the features exhibit statistically significant difference in the muscle fatigue and nonfatigue conditions. The maximum number of features (66%) is reduced by GA and BPSO for EMBD and BD-TFD respectively. The combination of EMBD- polynomial kernel based SVM is found to be most accurate (91% accuracy) in classifying the conditions with the features selected using GA. The proposed methods are found to be capable of handling the nonstationary and multicomponent variations of sEMG signals recorded in dynamic fatiguing contractions. Particularly, the combination of EMBD- polynomial kernel based SVM could be used to

  6. Using machine learning and surface reconstruction to accurately differentiate different trajectories of mood and energy dysregulation in youth.

    Science.gov (United States)

    Versace, Amelia; Sharma, Vinod; Bertocci, Michele A; Bebko, Genna; Iyengar, Satish; Dwojak, Amanda; Bonar, Lisa; Perlman, Susan B; Schirda, Claudiu; Travis, Michael; Gill, Mary Kay; Diwadkar, Vaibhav A; Sunshine, Jeffrey L; Holland, Scott K; Kowatch, Robert A; Birmaher, Boris; Axelson, David; Frazier, Thomas W; Arnold, L Eugene; Fristad, Mary A; Youngstrom, Eric A; Horwitz, Sarah M; Findling, Robert L; Phillips, Mary L

    2017-01-01

    Difficulty regulating positive mood and energy is a feature that cuts across different pediatric psychiatric disorders. Yet, little is known regarding the neural mechanisms underlying different developmental trajectories of positive mood and energy regulation in youth. Recent studies indicate that machine learning techniques can help elucidate the role of neuroimaging measures in classifying individual subjects by specific symptom trajectory. Cortical thickness measures were extracted in sixty-eight anatomical regions covering the entire brain in 115 participants from the Longitudinal Assessment of Manic Symptoms (LAMS) study and 31 healthy comparison youth (12.5 y/o;-Male/Female = 15/16;-IQ = 104;-Right/Left handedness = 24/5). Using a combination of trajectories analyses, surface reconstruction, and machine learning techniques, the present study aims to identify the extent to which measures of cortical thickness can accurately distinguish youth with higher (n = 18) from those with lower (n = 34) trajectories of manic-like behaviors in a large sample of LAMS youth (n = 115; 13.6 y/o; M/F = 68/47, IQ = 100.1, R/L = 108/7). Machine learning analyses revealed that widespread cortical thickening in portions of the left dorsolateral prefrontal cortex, right inferior and middle temporal gyrus, bilateral precuneus, and bilateral paracentral gyri and cortical thinning in portions of the right dorsolateral prefrontal cortex, left ventrolateral prefrontal cortex, and right parahippocampal gyrus accurately differentiate (Area Under Curve = 0.89;p = 0.03) youth with different (higher vs lower) trajectories of positive mood and energy dysregulation over a period up to 5years, as measured by the Parent General Behavior Inventory-10 Item Mania Scale. Our findings suggest that specific patterns of cortical thickness may reflect transdiagnostic neural mechanisms associated with different temporal trajectories of positive mood and energy dysregulation in youth. This approach has

  7. Structure-based sampling and self-correcting machine learning for accurate calculations of potential energy surfaces and vibrational levels

    Science.gov (United States)

    Dral, Pavlo O.; Owens, Alec; Yurchenko, Sergei N.; Thiel, Walter

    2017-06-01

    We present an efficient approach for generating highly accurate molecular potential energy surfaces (PESs) using self-correcting, kernel ridge regression (KRR) based machine learning (ML). We introduce structure-based sampling to automatically assign nuclear configurations from a pre-defined grid to the training and prediction sets, respectively. Accurate high-level ab initio energies are required only for the points in the training set, while the energies for the remaining points are provided by the ML model with negligible computational cost. The proposed sampling procedure is shown to be superior to random sampling and also eliminates the need for training several ML models. Self-correcting machine learning has been implemented such that each additional layer corrects errors from the previous layer. The performance of our approach is demonstrated in a case study on a published high-level ab initio PES of methyl chloride with 44 819 points. The ML model is trained on sets of different sizes and then used to predict the energies for tens of thousands of nuclear configurations within seconds. The resulting datasets are utilized in variational calculations of the vibrational energy levels of CH3Cl. By using both structure-based sampling and self-correction, the size of the training set can be kept small (e.g., 10% of the points) without any significant loss of accuracy. In ab initio rovibrational spectroscopy, it is thus possible to reduce the number of computationally costly electronic structure calculations through structure-based sampling and self-correcting KRR-based machine learning by up to 90%.

  8. Using machine learning and surface reconstruction to accurately differentiate different trajectories of mood and energy dysregulation in youth.

    Directory of Open Access Journals (Sweden)

    Amelia Versace

    Full Text Available Difficulty regulating positive mood and energy is a feature that cuts across different pediatric psychiatric disorders. Yet, little is known regarding the neural mechanisms underlying different developmental trajectories of positive mood and energy regulation in youth. Recent studies indicate that machine learning techniques can help elucidate the role of neuroimaging measures in classifying individual subjects by specific symptom trajectory. Cortical thickness measures were extracted in sixty-eight anatomical regions covering the entire brain in 115 participants from the Longitudinal Assessment of Manic Symptoms (LAMS study and 31 healthy comparison youth (12.5 y/o;-Male/Female = 15/16;-IQ = 104;-Right/Left handedness = 24/5. Using a combination of trajectories analyses, surface reconstruction, and machine learning techniques, the present study aims to identify the extent to which measures of cortical thickness can accurately distinguish youth with higher (n = 18 from those with lower (n = 34 trajectories of manic-like behaviors in a large sample of LAMS youth (n = 115; 13.6 y/o; M/F = 68/47, IQ = 100.1, R/L = 108/7. Machine learning analyses revealed that widespread cortical thickening in portions of the left dorsolateral prefrontal cortex, right inferior and middle temporal gyrus, bilateral precuneus, and bilateral paracentral gyri and cortical thinning in portions of the right dorsolateral prefrontal cortex, left ventrolateral prefrontal cortex, and right parahippocampal gyrus accurately differentiate (Area Under Curve = 0.89;p = 0.03 youth with different (higher vs lower trajectories of positive mood and energy dysregulation over a period up to 5years, as measured by the Parent General Behavior Inventory-10 Item Mania Scale. Our findings suggest that specific patterns of cortical thickness may reflect transdiagnostic neural mechanisms associated with different temporal trajectories of positive mood and energy dysregulation in youth. This

  9. Using of the surface activation method for enhancement of machine realibility

    International Nuclear Information System (INIS)

    Postnikov, V.I.; Garbar, I.N.

    1979-01-01

    A surface activation method is described for controlling the wear of units and details, allowing one to measure the wear at continuous operation of the mechanism by any program. The main advantages of the surface activation method for the wear tests are shown. By means of that method it was possible to develop a simultaneous controlling conjugate detail wear, and a method of different-activity brands, as well as the method for repeated activation of details. Development of theory for the engineering and technology of engine wear control by the surface activation method allowed one to improve the efficiency and reduce the time of research in the field of friction and wear

  10. Phase transformations during machining and properties of surface layers in zirconium dioxide ceramics

    International Nuclear Information System (INIS)

    Grigor'ev, O.N.; Krivoshej, G.S.; Stel'mashenko, N.A.; Trefilov, V.I.; Shevchenko, A.V.

    1991-01-01

    The methods of X-ray allow studying phase composition and inner stresses in the surface layers of partially stabilized zirconium dioxide after mashining. It is shown that under conditions of abrasive treatment transitions from tetragonal into rhomboedric and monoclinic phases initiate. As a result of phase transitions fields of compressible stresses achieving 900 MPa under grinding with ACM abrasive are created on the surface. An essential increase of hardness due to growth of the brittle fauilure resistance and deformation hardening is revealed

  11. Advanced measurement and analysis of surface textures produced by micro-machining processes

    International Nuclear Information System (INIS)

    Bordatchev, Evgueni V; Hafiz, Abdullah M K

    2014-01-01

    Surface texture of a part or a product has significant effects on its functionality, physical-mechanical properties and visual appearance. In particular for miniature products, the implication of surface quality becomes critical owing to the presence of geometrical features with micro/nano-scale dimensions. Qualitative and quantitative assessments of surface texture are carried out predominantly by profile parameters, which are often insufficient to address the contribution of constituent spatial components with varied amplitudes and wavelengths. In this context, this article presents a novel approach for advanced measurement and analysis of profile average roughness (R a ) and its spatial distribution at different wavelength intervals. The applicability of the proposed approach was verified for three different surface topographies prepared by grinding, laser micro-polishing and micro-milling processes. From the measurement and analysis results, R a (λ) spatial distribution was found to be an effective measure of revealing the contributions of various spatial components within specific wavelength intervals towards formation of the entire surface profile. In addition, the approach was extended to the measurement and analysis of areal average roughness S a (λ) spatial distribution within different wavelength intervals. Besides, the proposed method was demonstrated to be a useful technique in developing a functional correlation between a manufacturing process and its corresponding surface profile. (paper)

  12. Accuracy Enhancement with Processing Error Prediction and Compensation of a CNC Flame Cutting Machine Used in Spatial Surface Operating Conditions

    Directory of Open Access Journals (Sweden)

    Shenghai Hu

    2017-04-01

    Full Text Available This study deals with the precision performance of the CNC flame-cutting machine used in spatial surface operating conditions and presents an accuracy enhancement method based on processing error modeling prediction and real-time compensation. Machining coordinate systems and transformation matrix models were established for the CNC flame processing system considering both geometric errors and thermal deformation effects. Meanwhile, prediction and compensation models were constructed related to the actual cutting situation. Focusing on the thermal deformation elements, finite element analysis was used to measure the testing data of thermal errors, the grey system theory was applied to optimize the key thermal points, and related thermal dynamics models were carried out to achieve high-precision prediction values. Comparison experiments between the proposed method and the teaching method were conducted on the processing system after performing calibration. The results showed that the proposed method is valid and the cutting quality could be improved by more than 30% relative to the teaching method. Furthermore, the proposed method can be used under any working condition by making a few adjustments to the prediction and compensation models.

  13. Effect of pyrolysis atmospheres on the morphology of polymer-derived silicon oxynitrocarbide ceramic films coated aluminum nitride surface and the thermal conductivity of silicone rubber composites

    Science.gov (United States)

    Chiu, Hsien T.; Sukachonmakul, Tanapon; Wang, Chen H.; Wattanakul, Karnthidaporn; Kuo, Ming T.; Wang, Yu H.

    2014-02-01

    Amorphous silicon oxycarbide (SiOC) and silicon oxynitrocarbide (SiONC) ceramic films coated aluminum nitride (AlN) were prepared by using preceramic-polysilazane (PSZ) with dip-coating method, followed by pyrolysis at 700 °C in different (air, Ar, N2 and NH3) atmospheres to converted PSZ into SiOCair and SiONC(Ar,N2andNH3) ceramic. The existence of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface was characterized by FTIR, XRD and XPS. The interfacial adhesion between silicone rubber and AlN was significantly improved after the introduction of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. It can be observed from AFM that the pyrolysis of PSZ at different atmosphere strongly affected to films morphology on AlN surface as SiOCair and SiONCNH3 ceramic films were more flat and smooth than SiONCN2 and SiONCAr ceramic films. Besides, the enhancement of the thermal conductivity of silicone rubber composites was found to be related to the decrease in the surface roughness of SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. This present work provided an alternative surface modification of thermally conductive fillers to improve the thermal conductivity of silicon rubber composites by coating with amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films.

  14. In situ transmission electron microscopy observation of pulverization of aluminum nanowires and evolution of the thin surface Al2O3 layers during lithiation-delithiation cycles.

    Science.gov (United States)

    Liu, Yang; Hudak, Nicholas S; Huber, Dale L; Limmer, Steven J; Sullivan, John P; Huang, Jian Yu

    2011-10-12

    Lithiation-delithiation cycles of individual aluminum nanowires (NWs) with naturally oxidized Al(2)O(3) surface layers (thickness 4-5 nm) were conducted in situ in a transmission electron microscope. Surprisingly, the lithiation was always initiated from the surface Al(2)O(3) layer, forming a stable Li-Al-O glass tube with a thickness of about 6-10 nm wrapping around the NW core. After lithiation of the surface Al(2)O(3) layer, lithiation of the inner Al core took place, which converted the single crystal Al to a polycrystalline LiAl alloy, with a volume expansion of about 100%. The Li-Al-O glass tube survived the 100% volume expansion, by enlarging through elastic and plastic deformation, acting as a solid electrolyte with exceptional mechanical robustness and ion conduction. Voids were formed in the Al NWs during the initial delithiation step and grew continuously with each subsequent delithiation, leading to pulverization of the Al NWs to isolated nanoparticles confined inside the Li-Al-O tube. There was a corresponding loss of capacity with each delithiation step when arrays of NWs were galvonostatically cycled. The results provide important insight into the degradation mechanism of lithium-alloy electrodes and into recent reports about the performance improvement of lithium ion batteries by atomic layer deposition of Al(2)O(3) onto the active materials or electrodes.

  15. Hydroxy-Al and cell-surface negativity are responsible for the enhanced sensitivity of Rhodotorula taiwanensis to aluminum by increased medium pH.

    Science.gov (United States)

    Zhao, Xue Qiang; Bao, Xue Min; Wang, Chao; Xiao, Zuo Yi; Hu, Zhen Min; Zheng, Chun Li; Shen, Ren Fang

    2017-10-01

    Aluminum (Al) is ubiquitous and toxic to microbes. High Al 3+ concentration and low pH are two key factors responsible for Al toxicity, but our present results contradict this idea. Here, an Al-tolerant yeast strain Rhodotorula taiwanensis RS1 was incubated in glucose media containing Al with a continuous pH gradient from pH 3.1-4.2. The cells became more sensitive to Al and accumulated more Al when pH increased. Calculations using an electrostatic model Speciation Gouy Chapman Stern indicated that, the increased Al sensitivity of cells was associated with AlOH 2+ and Al(OH) 2 + rather than Al 3+ . The alcian blue (a positively charged dye) adsorption and zeta potential determination of cell surface indicated that, higher pH than 3.1 increased the negative charge and Al adsorption at the cell surface. Taken together, the enhanced sensitivity of R. taiwanensis RS1 to Al from pH 3.1-4.2 was associated with increased hydroxy-Al and cell-surface negativity.

  16. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  17. Investigation of material removal rate and surface roughness during wire electrical discharge machining (WEDM of Inconel 625 super alloy by cryogenic treated tool electrode

    Directory of Open Access Journals (Sweden)

    Ashish Goyal

    2017-10-01

    Full Text Available The present investigation focuses the effect of process parameters on material removal rate (MRR and surface roughness (Ra in wire electric discharge machining of Inconel 625. Machining was done by using a normal zinc coated wire and cryogenic treated zinc coated wire. The experiments were performed by considering different process parameters viz. tool electrode, current intensity, pulse on time, pulse off time, wire feed and wire tension. The thickness of work material and dia. of wire are kept constant. Taguchi L18 (21 * 35 orthogonal array of experimental design is used to perform the experiments. Analysis of variance (ANOVA is employed to optimize the material removal rate and surface roughness. Based on analysis it is found that pulse on time, tool electrode and current intensity are the significant parameters that affect the material removal rate and surface roughness. The scanning electron microscopy (SEM are used to identify the microstructure of the machined work piece.

  18. Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

    International Nuclear Information System (INIS)

    Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

    2015-01-01

    In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

  19. A Torque Error Compensation Algorithm for Surface Mounted Permanent Magnet Synchronous Machines with Respect to Magnet Temperature Variations

    Directory of Open Access Journals (Sweden)

    Chang-Seok Park

    2017-09-01

    Full Text Available This paper presents a torque error compensation algorithm for a surface mounted permanent magnet synchronous machine (SPMSM through real time permanent magnet (PM flux linkage estimation at various temperature conditions from medium to rated speed. As known, the PM flux linkage in SPMSMs varies with the thermal conditions. Since a maximum torque per ampere look up table, a control method used for copper loss minimization, is developed based on estimated PM flux linkage, variation of PM flux linkage results in undesired torque development of SPMSM drives. In this paper, PM flux linkage is estimated through a stator flux linkage observer and the torque error is compensated in real time using the estimated PM flux linkage. In this paper, the proposed torque error compensation algorithm is verified in simulation and experiment.

  20. Configuration design and accuracy analysis of a novel magneto rheological finishing machine tool for concave surfaces with small radius of curvature

    International Nuclear Information System (INIS)

    Liu, Henan; Chen, Mingjun; Yu, Bo; Zhen, Fang

    2016-01-01

    Magnetorheological finishing (MRF) is a computer-controlled deterministic polishing technique that is widely used in the production of high-quality optics. In order to overcome the defects of existing MRF processes that are unable to achieve concave surfaces with small radius of curvature, a configuration method of a novel structured MRF machine tool using small ball-end permanent-magnet polishing head is proposed in this paper. The preliminary design focuses on the structural configuration of the machine, which includes the machine body, motion units and accessory equipment, and so on. Structural deformation and fabrication accuracy of the machine are analyzed theoretically, in which the reasonable structure sizes, manufacturing errors and assembly errors of main structural components are given for configuration optimization. Based on the theoretical analysis, a four-axes linkage MRF machine tool is developed. Preliminary experiments of spot polishing are carried out and the results indicate that the proposed MRF process can achieve stable polishing area which meets requirement of deterministic polishing. A typical small-bore complex component is polished on the developed device and fine surface quality is obtained with sphericity of the finished spherical surfaces 1.3 μm and surface roughness Ra less than 0.018 μm.

  1. Investigation of Energy Absorption in Aluminum Foam Sandwich Panels By Drop Hammer Test: Experimental Results

    Directory of Open Access Journals (Sweden)

    Mohammad Nouri Damghani

    2016-05-01

    Full Text Available The sandwich panel structures with aluminum foam core and metal surfaces have light weight with high performance in dispersing energy. This has led to their widespread use in the absorption of energy. The cell structure of foam core is subjected to plastic deformation in the constant tension level that absorbs a lot of kinetic energy before destruction of the structure. In this research, by making samples of aluminum foam core sandwich panels with aluminum surfaces, experimental tests of low velocity impact by a drop machine are performed for different velocities and weights of projectile on samples of sandwich panels with aluminum foam core with relative density of 18%, 23%, and 27%. The output of device is acceleration‐time diagram which is shown by an accelerometer located on the projectile. From the experimental tests, the effect of weight, velocity and energy of the projectile and density of the foam on the global deformation, and energy decrease rate of projectile have been studied. The results of the experimental testes show that by increasing the density of aluminum foam, the overall impression is reduced and the slop of energy loss of projectile increases. Also by increasing the velocity of the projectile, the energy loss increases.

  2. 40 CFR 63.5749 - How do I calculate the organic HAP content of aluminum wipedown solvents?

    Science.gov (United States)

    2010-07-01

    ... Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5749 How do I calculate... fraction of organic HAP in aluminum wipedown solvent j. m = number of different aluminum surface coatings...

  3. Multiple-Objective Particle Swarm Optimization for Multi-Head Beam-Type Surface Mounting Machines

    NARCIS (Netherlands)

    Torabi, S.A.; Hamedi, M.; Ashayeri, J.

    2010-01-01

    The growing demand for electronic devices has made the manufacturing of printed circuit boards (PCBs) a promising industry over the last decades. As the demand for printed circuit boards increases, the industry becomes more dependent on highly automated assembly processes using Surface Mounting

  4. Enhancing structural integrity of adhesive bonds through pulsed laser surface micro-machining

    KAUST Repository

    Diaz, Edwin Hernandez

    2015-01-01

    of different kinds of heterogeneous surface properties that may replicate this behavior and the mechanisms at work. In order to do this, we used pulsed laser ablation on copper substrates (CuZn40) aiming to increase adhesion for bonding. A Yb-fiber laser

  5. Downscaling of Aircraft, Landsat, and MODIS-bases Land Surface Temperature Images with Support Vector Machines

    Science.gov (United States)

    High spatial resolution Land Surface Temperature (LST) images are required to estimate evapotranspiration (ET) at a field scale for irrigation scheduling purposes. Satellite sensors such as Landsat 5 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) can offer images at s...

  6. Surface topography of machined fibre reinforced plastics obtained by stylus instruments and optical profilometers

    DEFF Research Database (Denmark)

    Eriksen, Else; Hansen, Hans Nørgaard

    1998-01-01

    In the manufacturing industry it is important to be able to specify and control the surface quality of the components produced. This is often done with stylus profilometers, by which standardized roughness parameters are found. In recent years instruments based on laser autofocusing have been int...

  7. Application of response surface methodology for optimization of azocarmine B removal by heterogeneous photo-Fenton process using hydroxy-iron–aluminum pillared bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tianyuan, E-mail: xutianyuan1988@126.com; Liu, Yun, E-mail: liuyunscut@163.com; Ge, Fei, E-mail: gefei@xtu.edu.cn; Liu, Lin, E-mail: liulin861@163.com; Ouyang, Yuting, E-mail: oyt0225@126.com

    2013-09-01

    Hydroxy-iron–aluminum pillared bentonite (H-Fe–Al-B) was synthesized with ion exchange method, and its catalyst characteristics were analyzed by using X-ray diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The photo-Fenton catalytic activity of H-Fe–Al-B was tested under different reaction condition using azocarmine B (ACB) as model pollutant under ultraviolet light (UV) irradiation. The effects of three operating variables, initial dye concentration, initial pH value and H{sub 2}O{sub 2} concentration on the decolorization efficiency of ACB were optimized by response surface methodology (RSM) based on Box–Behnken design. The results showed that hydroxy aluminum iron ions intercalated into the interlayer spaces of bentonite successfully and H-Fe–Al-B had high photocatalytic activity. Analysis of variance (ANOVA) indicated that the proposed quadratic model could be used to navigate the design space. The proposed model was approximately in accordance with the experimental case with correlation coefficients R{sup 2}, R{sub adj}{sup 2} and R{sub pred}{sup 2} correlation coefficients of 0.9996, 0.9991 and 0.9934, respectively. The optimum conditions for ACB decolorization were dye concentration of 143.7 mg/L, pH of 4.2 and H{sub 2}O{sub 2} concentration of 17.7 mM, respectively. The predicted decolorization rate under the optimum conditions determined by the proposed model was 99.6%. Confirmatory tests were carried out under the optimum conditions and the decolorization rate of 99.5% was observed, which closely agreed with the predicted value.

  8. Pre-treatments applied to oxidized aluminum surfaces to modify the interfacial bonding with bis-1,2-(triethoxysilyl)ethane (BTSE)

    Energy Technology Data Exchange (ETDEWEB)

    Teo, M. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Kim, J. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Wong, P.C. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Wong, K.C. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Mitchell, K.A.R. [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada)]. E-mail: karm@chem.ubc.ca

    2005-12-15

    A remote microwave-generated H{sub 2} plasma and heating to 250 deg. C were separately used to modify high-purity oxidized aluminum surfaces and to assess whether these treatments can help enhance adhesion with bis-1,2-(triethoxysilyl)ethane (BTSE) coatings. Different initial oxide surfaces were considered, corresponding to the native oxide and to surfaces formed by the Forest Products Laboratory (FPL) treatment applied for either 15 or 60 min. BTSE is applied from solution at pH 4, and competing processes of etching, protonation (to form OH groups) and coupling (to form Al-O-Si interfacial bonds) occur at the solid-liquid interface. Scanning electron microscopy (SEM) was used to determine how the topographies of the modified Al surfaces changed with the different pre-treatments and with exposure to a buffer solution of pH 4. Secondary-ion mass spectrometry (SIMS) was used to determine the direct amount of Al-O-Si interfacial bonds by measuring the ratio of peak intensities 71-70 amu, while X-ray photoelectron spectroscopy (XPS) was used to determine the overall strength of the silane coating adhesion by measuring the Si 2p signals before and after application of an ultrasonic rinse to the coated sample. Measured Al 2p and O 1s spectra helped assess how the different pre-treatments modified the various Al oxidized surfaces prior to BTSE coating. Pre-treated samples that showed increased Al-O-Si bonding after BTSE coating corresponded to surfaces, which did not show evidence of significant etching after exposure to a pH 4 environment. This suggests that such surfaces are more receptive to the coupling reaction during exposure to the BTSE coating solution. These surfaces include all H{sub 2} plasma-treated samples, the heated native oxide and the sample that only received the 15 min FPL treatment. In contrast, other surfaces that show evidence of etching in pH 4 environments are samples that received lower amounts of Al-O-Si interfacial bonding. Overall, heating

  9. Computational Sensing of Staphylococcus aureus on Contact Lenses Using 3D Imaging of Curved Surfaces and Machine Learning.

    Science.gov (United States)

    Veli, Muhammed; Ozcan, Aydogan

    2018-03-27

    We present a cost-effective and portable platform based on contact lenses for noninvasively detecting Staphylococcus aureus, which is part of the human ocular microbiome and resides on the cornea and conjunctiva. Using S. aureus-specific antibodies and a surface chemistry protocol that is compatible with human tears, contact lenses are designed to specifically capture S. aureus. After the bacteria capture on the lens and right before its imaging, the captured bacteria are tagged with surface-functionalized polystyrene microparticles. These microbeads provide sufficient signal-to-noise ratio for the quantification of the captured bacteria on the contact lens, without any fluorescent labels, by 3D imaging of the curved surface of each lens using only one hologram taken with a lens-free on-chip microscope. After the 3D surface of the contact lens is computationally reconstructed using rotational field transformations and holographic digital focusing, a machine learning algorithm is employed to automatically count the number of beads on the lens surface, revealing the count of the captured bacteria. To demonstrate its proof-of-concept, we created a field-portable and cost-effective holographic microscope, which weighs 77 g, controlled by a laptop. Using daily contact lenses that are spiked with bacteria, we demonstrated that this computational sensing platform provides a detection limit of ∼16 bacteria/μL. This contact-lens-based wearable sensor can be broadly applicable to detect various bacteria, viruses, and analytes in tears using a cost-effective and portable computational imager that might be used even at home by consumers.

  10. A surface embossing technique to create micro-grooves on an aluminum fin stock for drainage enhancement

    International Nuclear Information System (INIS)

    Liu Liping; Jacobi, Anthony M; Chvedov, Dmitri

    2009-01-01

    Recent advances using a surface embossing technique allow us to inexpensively impart micro-scale surface features on heat exchanger construction material, which we exploit to reduce condensate retention. The retention of condensate is important to the performance of heat exchangers in a broad range of air-cooling and dehumidification applications. We report a study of wetting behavior and drainage performance on a series of embossed surfaces with different micro-groove dimensions. Static contact angles, critical sliding angles, droplet aspect ratios, etc, are reported with detailed surface topographical information. Our results show that unless the spacing between grooves is very large (>100 µm), the parallel-grooved surface feature normally increases the apparent contact angle of a droplet on the surface. The micro-groove structure causes anisotropic wetting behavior of the droplets, and apparent contact angles measured by viewing along with the micro-grooves (θ p erpendicular) were found to be larger than those measured from the other direction (θ || ) (by viewing perpendicular to the grooves). A consistent reduction of a critical sliding angle was observed on surfaces after embossing (the micro-grooves are aligned to be parallel with gravity). This may be due to contact line discontinuities and contact-line pinning induced by a groove structure of the surface. Water droplets exhibit an elongated shape along the micro-grooves, which is in contrast to the nearly circular base contour observed on an isotropic surface. Smaller groove spacing, larger depth and steeper sidewalls are observed to be favorable for drainage enhancement and recommended as design guidelines in the future

  11. Laser-induced damage of fused silica at 355 and 1065 nm initiated at aluminum contamination particles on the surface

    International Nuclear Information System (INIS)

    Genin, F.Y.; Michlitsch, K.; Furr, J.; Kozlowski, M.R.; Krulevitch, P.

    1997-01-01

    1-μm thick circular dots, 10-250 μm dia, were deposited onto 1.14 cm thick fused silica windows by sputtering Al through a mask. Al shavings were also deposited on the windows to investigate effects of particle-substrate adhesion. The silica windows were then illuminated repetitively using a 3-ns, 355 nm and an 8.6-ns, 1064 nm laser. The tests were conducted at near normal incidence with particles on input and output surfaces of the windows. During the first shot, a plasma ignited at the metal particle and damage initiated on the fused silica surface. The morphology of the damage at the metal dots were reproducible but different for input and output surface contamination. For input surface contamination, minor damage occurred where the particle was located; such damage ceased to grow with the removal of contaminant material. More serious damage (pits and cracks) was initiated on the output surface (especially at 355 nm) and grew to catastrophic proportions after few shots. Output surface contaminants were usually ejected on the initial shot, leaving a wave pattern on the surface. No further damage occurred with subsequent shots unless a shot (usually the first shot) cracked the surface; such behavior was mostly observed at 355 nm and occasionally for large shavings at 1064 nm. The size of the damaged area scaled with the size of the particle (except when catastrophic damage occurred). Onset of catastrophic damage on output surface occurred only when particles exceeded a critical size. Damage behavior of the sputtered dots was found to be qualitatively similar to that of the shavings. The artificial contamination technique accelerated the study by allowing better control of the test conditions

  12. Artificial Intelligence Monitoring of Hardening Methods and Cutting Conditions and Their Effects on Surface Roughness, Performance, and Finish Turning Costs of Solid-State Recycled Aluminum Alloy 6061 Сhips

    Directory of Open Access Journals (Sweden)

    Adel Taha Abbas

    2018-05-01

    Full Text Available Aluminum Alloy 6061 components are frequently manufactured for various industries—aeronautics, yachting, and optical instruments—due to their excellent physical and mechanical properties, including corrosion resistance. There is little research on the mechanical tooling of AA6061 and none on its structure and properties and their effects on surface roughness after finish turning. The objective of this comprehensive study is, therefore, to ascertain the effects of both the modern method of hardening AA6061 shafts and the finish turning conditions on surface roughness, Ra, and the minimum machining time for unit-volume removal, Tm, while also establishing the cost price of processing one part, C. The hardening methods improved both the physical and the mechanical material properties processed with 2, 4, and 6 passes of equal channel angular pressing (ECAP at room temperature, using an ECAP-matrix with a channel angle of 90°. The reference workpiece sample was a hot extruded chip under an extrusion ratio (ER of 5.2 at an extrusion temperature of 500 °С (ET = 500 °C. The following results were obtained: grain size in ECAP-6 decreased from 15.9 to 2.46 μm, increasing both microhardness from 41 Vickers hardness value (HV to 110 HV and ultimate tensile strength from 132.4 to 403 MPa. The largest decrease in surface roughness, Ra—70%, was obtained turning a workpiece treated with ECAP-6. The multicriteria optimization was computed in a multilayer perceptron-based artificial neural network that yielded the following optimum values: the minimal length of the three-dimensional estimates vector with the coordinates Ra = 0.800 μm, Tm = 0.341 min/cm3, and С = 6.955 $ corresponded to the optimal finish turning conditions: cutting speed vc = 200 m/min, depth of cut ap = 0.2 mm, and feed per revolution fr = 0.103 mm/rev (ET-500 extrusion without hardening.

  13. Design and calibration of a scanning tunneling microscope for large machined surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, D.A.; Russell, P.E.; Dow, T.A.

    1988-12-01

    During the last year the large sample STM has been designed, built and used for the observation of several different samples. Calibration of the scanner for prope dimensional interpretation of surface features has been a chief concern, as well as corrections for non-linear effects such as hysteresis during scans. Several procedures used in calibration and correction of piezoelectric scanners used in the laboratorys STMs are described.

  14. Optical probe for porosity defect detection on inner diameter surfaces of machined bores

    Science.gov (United States)

    Kulkarni, Ojas P.; Islam, Mohammed N.; Terry, Fred L.

    2010-12-01

    We demonstrate an optical probe for detection of porosity inside spool bores of a transmission valve body with diameters down to 5 mm. The probe consists of a graded-index relay rod that focuses a laser beam spot onto the inner surface of the bore. Detectors, placed in the specular and grazing directions with respect to the incident beam, measure the change in scattered intensity when a surface defect is encountered. Based on the scattering signatures in the two directions, the system can also validate the depth of the defect and distinguish porosity from bump-type defects coming out of the metal surface. The system can detect porosity down to a 50-μm lateral dimension and ~40 μm in depth with >3-dB contrast over the background intensity fluctuations. Porosity detection systems currently use manual inspection techniques on the plant floor, and the demonstrated probe provides a noncontact technique that can help automotive manufacturers meet high-quality standards during production.

  15. Infrared radiation properties of anodized aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kohara, S. [Science Univ. of Tokyo, Noda, Chiba (Japan). Dept. of Materials Science and Technology; Niimi, Y. [Science Univ. of Tokyo, Noda, Chiba (Japan). Dept. of Materials Science and Technology

    1996-12-31

    The infrared radiation heating is an efficient and energy saving heating method. Ceramics have been used as an infrared radiant material, because the emissivity of metals is lower than that of ceramics. However, anodized aluminum could be used as the infrared radiant material since an aluminum oxide film is formed on the surface. In the present study, the infrared radiation properties of anodized aluminum have been investigated by determining the spectral emissivity curve. The spectral emissivity curve of anodized aluminum changed with the anodizing time. The spectral emissivity curve shifted to the higher level after anodizing for 10 min, but little changed afterwards. The infrared radiant material with high level spectral emissivity curve can be achieved by making an oxide film thicker than about 15 {mu}m on the surface of aluminum. Thus, anodized aluminum is applicable for the infrared radiation heating. (orig.)

  16. A parametric study of surface roughness and bonding mechanisms of aluminum alloys with epoxies: a molecular dynamics simulation

    Science.gov (United States)

    Timilsina, Rajendra; Termaath, Stephanie

    The marine environment is highly aggressive towards most materials. However, aluminium-magnesium alloys (Al-Mg, specifically, 5xxx series) have exceptionally long service life in such aggressive marine environments. For instance, an Al-Mg alloy, AA5083, is extensively used in naval structures because of its good mechanical strength, formability, seawater corrosion resistance and weldability. However, bonding mechanisms of these alloys with epoxies in a rough surface environment are not fully understood yet. It requires a rigorous investigation at molecular or atomic levels. We performed a molecular dynamics simulation to study an adherend surface preparation and surface bonding mechanisms of Al-Mg alloy (AA5083) with different epoxies by developing several computer models. Various distributions of surface roughness are introduced in the models and performed molecular dynamics simulations. Formation of a beta phase (Al3Mg2) , microstructures, bonding energies at the interface, bonding strengths and durability are investigated. Office of Naval Research.

  17. The desorption of Phosphorous (32 P) fixed on iron and aluminum oxy-hydroxide surfaces by the soil microbial biomass

    International Nuclear Information System (INIS)

    Araujo, Lilian Maria Cesar de.

    1995-02-01

    This work determines whether the soil microbial biomass, with an ample supply of available C, can utilize P adsorber in the surfaces of oxy-hydroxides of Fe or Al of soil-P deficient soils. To simulate the surfaces of the natural Fe and Al compounds, synthetic oxy-hydroxides of Fe and Al, impregnated in strips of filter paper, and containing P tagged with 32 P, were used. (author). 60 refs., 7 figs., 7 tabs

  18. Experimental investigation of time and repeated cycles in nucleate pool boiling of alumina/water nanofluid on polished and machined surfaces

    Science.gov (United States)

    Rajabzadeh Dareh, F.; Haghshenasfard, M.; Nasr Esfahany, M.; Salimi Jazi, H.

    2018-06-01

    Pool boiling heat transfer of pure water and nanofluids on a copper block has been studied experimentally. Nanofluids with various concentrations of 0.0025, 0.005 and 0.01 vol.% are employed and two simple surfaces (polished and machined copper surface) are used as the heating surfaces. The results indicated that the critical heat flux (CHF) in boiling of fluids on the polished surface is 7% higher than CHF on the machined surface. In the case of machined surface, the heat transfer coefficient (HTC) of 0.01 vol.% nanofluid is about 37% higher than HTC of base fluid, while in the polished surface the average HTC of 0.01% nanofluid is about 19% lower than HTC of the pure water. The results also showed that the boiling time and boiling cycles on the polished surface changes the heat transfer performance. By increasing the boiling time from 5 to 10 min, the roughness enhances about 150%, but by increasing the boiling time to 15 min, the roughness enhancement is only 8%.

  19. Generation of helical gears with new surfaces topology by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.; Hsiao, C. L.; Handschuh, Robert F.

    1993-01-01

    Analysis of helical involute gears by tooth contact analysis shows that such gears are very sensitive to angular misalignment that leads to edge contact and the potential for high vibration. A new topology of tooth surfaces of helical gears that enables a favorable bearing contact and a reduced level of vibration is described. Methods for grinding of the helical gears with the new topology are proposed. A TCA (tooth contact analysis) program for simulation of meshing and contact of helical gears with the new topology has been developed. Numerical examples that illustrate the proposed ideas are discussed.

  20. A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

    Directory of Open Access Journals (Sweden)

    Mitul Kumar Mishra

    2013-01-01

    Full Text Available Background and Objectives: Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation. Subjects and Methods: A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage. Results: Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change. Interpretation and Conclusion: In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface

  1. The Invention Convention: Mind Meets Simple Machines.

    Science.gov (United States)

    Hadi-Tabassum, Samina

    1997-01-01

    Describes an Earth Day celebration where students had to design an invention made of simple machines that could crush an empty aluminum can through 10 rapid mechanical movements using materials foraged from the students' homes. (JRH)

  2. Chemical surface modification of glass beads for the treatment of paper machine process waters

    International Nuclear Information System (INIS)

    Jradi, Khalil; Daneault, Claude; Chabot, Bruno

    2011-01-01

    Adsorption of detrimental contaminants on a solid sorbent is proposed to remove these contaminants from process waters to increase water recycling and reduce effluent loads in the papermaking industry. A self-assembly process of attaching (covalent grafting) cationic aminosilane molecules to glass beads was investigated. The existence and the hydrolytic stability of self-assembled monolayers and multilayers were confirmed by X-Ray Photoelectron Spectroscopy and contact angle measurements. Effects of reaction time and curing on aminosilane layer structures are also discussed. The curing step after silanization seems to be crucial in the hydrophobization of the quaternary ammonium silane coated onto glass beads, and curing could affect the final chemical structure of the ammonium groups of grafted organosilane. Results indicated that modified glass beads have a strong hydrophobicity, which is attributed to the hydrophobic property of the longest carbon chain grafted onto the glass surface. Adsorption of a model contaminant (stearic acid) onto chemically modified glass beads was determined using colloidal titration. Hydrophobic interactions could be the main driving force involved between the long carbon chains of stearic acid and the carbon chains of the aminosilane layers on glass bead surfaces. Finally, self-assembly processes applied onto glass beads may have two promising applications for papermaking and self-cleaning systems.

  3. The effect of surface corrosion damage on the fatigue life of 6061-T6 aluminum alloy extrusions

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Matthew; Eason, Paul D.; Özdeş, Hüseyin; Tiryakioğlu, Murat, E-mail: m.tiryakioglu@unf.edu

    2017-04-06

    An investigation was performed where 6061-T6 extrusions were exposed to a 3.5% NaCl solution at pH 2 for 2 days and 24 days to create distinct surface flaws. The effect of these flaws on the rotating beam fatigue life was then investigated and analyzed by using Wöhler curves, Weibull statistics and scanning electron microscopy (SEM). It was determined that corrosion damage reduced the fatigue life significantly and specimens corroded for both 2-days and 24-days exhibited similar fatigue lives. Statistical analyses showed that fatigue life of all three datasets followed the 3-parameter Weibull distribution and the difference between the fatigue lives of two corroded datasets was statistically insignificant. Analysis of fracture surfaces showed that sizes of pits that led to fatigue crack initiation were very different in the two corroded datasets. Implications of the similarity in fatigue lives despite disparity in surface condition are discussed in detail in the paper.

  4. Effects of electrical discharge surface modification of superalloy Haynes 230 with aluminum and molybdenum on oxidation behavior

    International Nuclear Information System (INIS)

    Bai, C.-Y.

    2007-01-01

    The effects of the electrical discharge alloying (EDA) process on improving the high temperature oxidation resistance of the Ni-based superalloy Haynes 230 have been investigated. The 85 at.% Al and 15 at.% Mo composite electrode provided the surface alloying materials. An Al-rich layer is produced on the surface of the EDA specimen alloyed with positive electrode polarity, whereas, many discontinuous piled layers are attached to the surface of the EDA superalloy when negative electrode polarity is selected. The oxidation resistance of the specimen alloyed with positive electrode polarity is better than that of the unalloyed superalloy, and the effective temperature of oxidation resistance of the alloyed layer can be achieved to 1100 o C. Conversely, the oxidation resistance of the other EDA specimen alloyed with negative electrode polarity is even worse than that of the unalloyed superalloy

  5. To address surface reaction network complexity using scaling relations machine learning and DFT calculations

    International Nuclear Information System (INIS)

    Ulissi, Zachary W.; Medford, Andrew J.; Bligaard, Thomas; Nørskov, Jens K.

    2017-01-01

    Surface reaction networks involving hydrocarbons exhibit enormous complexity with thousands of species and reactions for all but the very simplest of chemistries. We present a framework for optimization under uncertainty for heterogeneous catalysis reaction networks using surrogate models that are trained on the fly. The surrogate model is constructed by teaching a Gaussian process adsorption energies based on group additivity fingerprints, combined with transition-state scaling relations and a simple classifier for determining the rate-limiting step. The surrogate model is iteratively used to predict the most important reaction step to be calculated explicitly with computationally demanding electronic structure theory. Applying these methods to the reaction of syngas on rhodium(111), we identify the most likely reaction mechanism. Lastly, propagating uncertainty throughout this process yields the likelihood that the final mechanism is complete given measurements on only a subset of the entire network and uncertainty in the underlying density functional theory calculations.

  6. Study of Surface Roughness and Cutting force in machining for 6068 Aluminium alloy

    Science.gov (United States)

    Purushothaman, D.; Kaushik Yanamundra, Krishna; Krishnan, Gokul; Perisamy, C.

    2018-04-01

    Metal matrix composites, in particular, Aluminium Hybrid Composites are gaining increasing attention for applications in air and land because of their superior strength to weight ratio, density and high temperature resistance. Aluminium alloys are being used for a wide range of applications in Aerospace and Automobile industries, to name a few. The Aluminium Alloy 6068 has been used as the specimen. It is mainly composed of Aluminium (93.22 - 97.6 %), Magnesium (0.60 - 1.2 %), Silicon (0.60 - 1.4 %) and Bismuth (0.60 - 1.1 %). Aluminium 6068 is widely used for manufacturing aircraft structures, fuselages and wings. It is also extensively used in fabricating automobile parts such as wheel spacers. In this study, tests for the measurement of surface roughness and cutting force has been carried out on the specimen, the results evaluated and conclusions are drawn. Also the simulation of the same is carried out in a commercial FE software – ABAQUS.

  7. Detection of small surface defects using DCT based enhancement approach in machine vision systems

    Science.gov (United States)

    He, Fuqiang; Wang, Wen; Chen, Zichen

    2005-12-01

    Utilizing DCT based enhancement approach, an improved small defect detection algorithm for real-time leather surface inspection was developed. A two-stage decomposition procedure was proposed to extract an odd-odd frequency matrix after a digital image has been transformed to DCT domain. Then, the reverse cumulative sum algorithm was proposed to detect the transition points of the gentle curves plotted from the odd-odd frequency matrix. The best radius of the cutting sector was computed in terms of the transition points and the high-pass filtering operation was implemented. The filtered image was then inversed and transformed back to the spatial domain. Finally, the restored image was segmented by an entropy method and some defect features are calculated. Experimental results show the proposed small defect detection method can reach the small defect detection rate by 94%.

  8. A comparison RSM and ANN surface roughness models in thin-wall machining of Ti6Al4V using vegetable oils under MQL-condition

    Science.gov (United States)

    Mohruni, Amrifan Saladin; Yanis, Muhammad; Sharif, Safian; Yani, Irsyadi; Yuliwati, Erna; Ismail, Ahmad Fauzi; Shayfull, Zamree

    2017-09-01

    Thin-wall components as usually applied in the structural parts of aeronautical industry require significant challenges in machining. Unacceptable surface roughness can occur during machining of thin-wall. Titanium product such Ti6Al4V is mostly applied to get the appropriate surface texture in thin wall designed requirements. In this study, the comparison of the accuracy between Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) in the prediction of surface roughness was conducted. Furthermore, the machining tests were carried out under Minimum Quantity Lubrication (MQL) using AlCrN-coated carbide tools. The use of Coconut oil as cutting fluids was also chosen in order to evaluate its performance when involved in end milling. This selection of cutting fluids is based on the better performance of oxidative stability than that of other vegetable based cutting fluids. The cutting speed, feed rate, radial and axial depth of cut were used as independent variables, while surface roughness is evaluated as the dependent variable or output. The results showed that the feed rate is the most significant factors in increasing the surface roughness value followed by the radial depth of cut and lastly the axial depth of cut. In contrary, the surface becomes smoother with increasing the cutting speed. From a comparison of both methods, the ANN model delivered a better accuracy than the RSM model.

  9. Scientific Background for Processing of Aluminum Waste

    Science.gov (United States)

    Kononchuk, Olga; Alekseev, Alexey; Zubkova, Olga; Udovitsky, Vladimir

    2017-11-01

    Changing the source of raw materials for producing aluminum and the emergence of a huge number of secondary alumina waste (foundry slag, sludge, spent catalysts, mineral parts of coal and others that are formed in various industrial enterprises) require the creation of scientific and theoretical foundations for their processing. In this paper, the aluminum alloys (GOST 4784-97) are used as an alu