WorldWideScience

Sample records for aluminum alloyed contacts

  1. Corrosion protection of aluminum alloys in contact with other metals

    Science.gov (United States)

    Kuster, C. A.

    1969-01-01

    Study establishes the quality of chemical and galvanized protection afforded by anodized and aldozided coatings applied to test panels of various aluminum alloys. The test panels, placed in firm contact with panels of titanium alloys, were subjected to salt spray tests and visually examined for corrosion effect.

  2. Aluminum alloy

    Science.gov (United States)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  3. 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.

  4. Numerical Modeling of Frictional Stress in the Contact Zone of Direct Extrusion of Aluminum Alloys under Starved Lubrication

    Science.gov (United States)

    Tomar, P.; Pandey, R. K.; Nath, Y.

    2013-11-01

    The objective of this article is to investigate numerically frictional stress in the contact zone at the die/billet interface in the direct extrusion of aluminum alloys considering starved lubricated conditions. In the modeling, both the inlet and work zones have been investigated by coupled solution of the governing equations. The influences of the billet material's strain hardening and its heating due to the plastic deformation are accounted for in the numerical computation. The frictional shear stress at the die/billet interface is computed using three different lubricating oils. Numerical results have been presented herein for the various operating parameters viz. starvation factor ( ψ = 0.2-0.6), lubricants' viscosities ( η 0 = 0.05 Pa s-0.2 Pa s), semi die angle ( β = 10°-20°), and material parameter ( G = 0.56-2.25). It has been observed that the frictional stress increases with an increase in the severity of the lubricant's starvation for the given values of semi-die angle, extrusion speed, and material parameter.

  5. Aluminum break-point contacts

    NARCIS (Netherlands)

    Heinemann, Martina; Groot, R.A. de

    1997-01-01

    Ab initio molecular dynamics is used to study the contribution of a single Al atom to an aluminum breakpoint contact during the final stages of breaking and the initial stages of the formation of such a contact. A hysteresis effect is found in excellent agreement with experiment and the form of the

  6. Modeling dissolution in aluminum alloys

    Science.gov (United States)

    Durbin, Tracie Lee

    2005-07-01

    Aluminum and its alloys are used in many aspects of modern life, from soda cans and household foil to the automobiles and aircraft in which we travel. Aluminum alloy systems are characterized by good workability that enables these alloys to be economically rolled, extruded, or forged into useful shapes. Mechanical properties such as strength are altered significantly with cold working, annealing, precipitation-hardening, and/or heat-treatments. Heat-treatable aluminum alloys contain one or more soluble constituents such as copper, lithium, magnesium, silicon and zinc that individually, or with other elements, can form phases that strengthen the alloy. Microstructure development is highly dependent on all of the processing steps the alloy experiences. Ultimately, the macroscopic properties of the alloy depend strongly on the microstructure. Therefore, a quantitative understanding of the microstructural changes that occur during thermal and mechanical processing is fundamental to predicting alloy properties. In particular, the microstructure becomes more homogeneous and secondary phases are dissolved during thermal treatments. Robust physical models for the kinetics of particle dissolution are necessary to predict the most efficient thermal treatment. A general dissolution model for multi-component alloys has been developed using the front-tracking method to study the dissolution of precipitates in an aluminum alloy matrix. This technique is applicable to any alloy system, provided thermodynamic and diffusion data are available. Treatment of the precipitate interface is explored using two techniques: the immersed-boundary method and a new technique, termed here the "sharp-interface" method. The sharp-interface technique is based on a variation of the ghost fluid method and eliminates the need for corrective source terms in the characteristic equations. In addition, the sharp-interface method is shown to predict the dissolution behavior of precipitates in aluminum

  7. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk

    2008-08-01

    Full Text Available The cast machine parts are widely used in many branches of industry. A very important issue is gaining the appropriate knowledge relating to the application of castings in places of explosion risks including but not limited to mining, chemical industry and rescue works. A possibility of explosion risks occurrence following the impact sparkling of the cast metal parts is still not solved problem in scientific research. In relation to this issue, in this article, the results of the study are presented, and relating to the tendency to impact sparkling of the aluminium alloys used in machine building. On the grounds of the results obtained, it was demonstrated that the registered impact sparkles bunches of feathers from the analyzed alloys: AlSi7Mg, (AK7; AlSi9Mg, (AK9; AlSi6Cu4, (AK64 and AlSi11, (AK11 show significant differences between each other. The quantitative analysis of the temperature distribution and nuclei surface area performed on the example of the alloy AK9 (subjected to defined period of corrosion allows for the statement that they are dangerous in conditions of explosion risk. Following this fact, designers and users of machine parts made from these materials should not use them in conditions where the explosive mixtures occur.

  8. Kinetics of aluminum lithium alloys

    Science.gov (United States)

    Pletcher, Ben A.

    2009-12-01

    Aluminum lithium alloys are increasingly used in aerospace for their high strength-to-weight ratio. Additions of lithium, up to 4.2 wt% decrease the alloy density while increasing the modulus and yield strength. The metastable, second phase Al3Li or delta' is intriguing, as it remains spherical and coherent with the matrix phase, alpha, well into the overaged condition. Small interfacial strain energy allows these precipitates to remain spherical for volume fractions (VV ) of delta' less than 0.3, making this alloy system ideal for investigation of late-stage coarsening phenomena. Experimental characterization of three binary Al-Li alloys are presented as a critical test of diffusion screening theory and multi-particle diffusion simulations. Quantitative transmission electron microscopy is used to image the precipitates directly using the centered dark-field technique. Images are analyzed autonomously within a novel Matlab function that determines the center and size of each precipitate. Particle size distribution, particle growth kinetics, and maximum particle size are used to track the precipitate growth and correlate with the predictions of screening theory and multi-particle diffusion simulations. This project is the first extensive study of Al-Li alloys, in over 25 years, applying modern transmission electron microscopy and image analysis techniques. Previous studies sampled but a single alloy composition, and measured far fewer precipitates. This study investigates 3 alloys with volume fractions of the delta precipitates, VV =0.1-0.27, aged at 225C for 1 to 10 days. More than 1000 precipitates were sampled per aging time, creating more statistically significant data. Experimental results are used to test the predictions based on diffusion screening theory and multi-particle aging simulations. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  9. Optical Transmittance of Anodically Oxidized Aluminum Alloy

    Science.gov (United States)

    Saito, Mitsunori; Shiga, Yasunori; Miyagi, Mitsunobu; Wada, Kenji; Ono, Sachiko

    1995-06-01

    Optical transmittance and anisotropy of anodic oxide films that were made from pure aluminum and an aluminum alloy (A5052) were studied. The alloy oxide film exhibits an enhanced polarization function, particularly when anodization is carried out at a large current density. It was revealed by chemical analysis that the alloy oxide film contains a larger amount of unoxidized aluminum than the pure-aluminum oxide film. The polarization function can be elucidated by considering unoxidized aluminum particles that are arranged in the columnar structure of the alumina film. Electron microscope observation showed that many holes exist in the alloy oxide film, around which columnar cells are arranged irregularly. Such holes and irregular cell arrangement cause the increase in the amount of unoxidized aluminum, and consequently induces scattering loss.

  10. Low-aluminum content iron-aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J. [and others

    1995-06-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10 and iron = 83.71. The ignots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot-worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  11. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  12. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  13. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  14. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  15. NASA-427: A New Aluminum Alloy

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

  16. Subsurface Aluminum Nitride Formation in Iron-Aluminum Alloys

    Science.gov (United States)

    Bott, June H.

    Transformation-induced plasticity (TRIP) steels containing higher amounts of aluminum than conventional steels are ideal for structural automotive parts due to their mechanical properties. However, the aluminum tends to react with any processing environment at high temperatures and therefore presents significant challenges during manufacturing. One such challenge occurs during secondary cooling, reheating, and hot-rolling and is caused by a reaction with nitrogen-rich atmospheres wherein subsurface aluminum nitride forms in addition to internal and external oxides. The nitrides are detrimental to mechanical properties and cause surface cracks. It is important to understand how these nitrides and oxides form and their consequences for the quality of steel products. This study looks at model iron-aluminum (up to 8 wt.% aluminum) alloys and uses confocal laser scanning microscopy, x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectrometry, and transmission electron microscopy to study the effect of various conditions on the growth and development of these precipitates in a subsurface oxygen-depleted region. By using model alloys and controlling the experimental atmosphere, this study is able to understand some of the more fundamental materials science behind aluminum nitride formation in aluminum-rich iron alloys and the relationship between internal nitride and oxide precipitation and external oxide scale morphology and composition. The iron-aluminum alloys were heated in N2 atmospheres containing oxygen impurities. It was found that nitrides formed when bulk aluminum content was below 8 wt.% when oxygen was sufficiently depleted due to the internal oxidation. In the samples containing 1 wt.% aluminum, the depth of the internal oxide and nitride zones were in agreement with a diffusion-based model. Increasing aluminum content to 3 and 5 wt% had the effects of modifying the surface-oxide scale composition and increasing its continuity

  17. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T(e and N(e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T(e and N(e for the aluminum in aluminum alloys using an optical fiber probe.

  18. Composite purification technology and mechanism of recycled aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    房文斌; 耿耀宏; 安阁英; 叶荣茂

    2002-01-01

    Iron-rich inclusions in aluminum alloys can be effectively removed by composite purification of sedimentation and filtration technology.The results show that the purposed method has no negative effects on aluminum alloys and obviously improve their mechanical properties.

  19. Casting Characteristics of Aluminum Die Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  20. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

    The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

  1. Multilayer Clad Plate of Stainless Steel/Aluminum/Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    YUAN Jiawei; PANG Yuhua; LI Ting

    2011-01-01

    The 3, 5, 20 layer clad plate from austenitic stainless steel, pure aluminum and aluminum alloy sheets were fabricated in different ways. The stretch and interface properties were measured. The result shows that 20 layer clad plate is better than the others. Well-bonded clad plate was successfully obtained in the following procedure: Basic clad sheet from 18 layer A11060/A13003sheets was firstly obtained with an initial rolling reduction of 44% at 450 ℃, followed by annealing at 300 ℃, and then with reduction of 50% at 550 ℃ from STS304 on each side. The best 20 layer clad plate was of 129 MPa bonding strength and 225 MPa stretch strength.

  2. Aluminum alloy nanosecond vs femtosecond laser marking

    Indian Academy of Sciences (India)

    S Rusu; A Buzaianu; D G Galusca; L Ionel; D Ursescu

    2013-11-01

    Based on the lack of consistent literature publications that analyse the effects of laser marking for traceability on various materials, the present paper proposes a study of the influence of such radiation processing on an aluminum alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser marking has been carried out, besides the standard commercial nanosecond engraving. All the marks have been analysed using profilometry, overhead and cross-section SEM microscopy, respectively and EDAX measurements.

  3. Fabrication of superhydrophobic nanostructured surface on aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, R.; Farzaneh, M. [Universite du Quebec a Chicoutimi, Chicoutimi, QC (Canada)

    2011-01-15

    A superhydrophobic surface was prepared by consecutive immersion in boiling water and sputtering of polytetrafluoroethylene (PTFE or Teflon registered) on the surface of an aluminum alloy substrate. Immersion in boiling water was used to create a micro-nanostructure on the alloy substrate. Then, the rough surface was coated with RF-sputtered Teflon film. The immersion time in boiling water plays an important role in surface morphology and water repellency of the deposited Teflon coating. Scanning electron microscopy images showed a ''flower-like'' structure in first few minutes of immersion. And as the immersion time lengthened, a ''cornflake'' structure appeared. FTIR analyses of Teflon-like coating deposited on water treated aluminum alloy surfaces showed fluorinated groups, which effectively reduce surface energy. The Teflon-like coating deposited on a rough surface achieved with five-minute immersion in boiling water provided a high static contact angle ({proportional_to}164 ) and low contact angle hysteresis ({proportional_to}4 ). (orig.)

  4. The Technological Improvements of Aluminum Alloy Coloring by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    LI Nai-jun

    2004-01-01

    The technological process of coloring golden-tawny on aluminum alloy by electrolysis was improved in this paper. The optimum composition of electrolyte was found, the conditions of deposition and anodic oxidation by electrolysis were studied. The oxidative membrane on aluminum alloy was satisfying, the colored aluminum alloy by electrolysis is uniformity,bright and beautiful, and the coloring by electrolysis is convenient and no pollution.

  5. China’s Aluminum Alloy Cable Market has Taken Shape

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>Aluminum alloy cable is a mature product and technology that has been used for nearly fifty years in the U.S.Through six years’promotion,it has been widely recognized and accepted in the China market since 2013,which laid the foundation for the development of the aluminum alloy cable market.Aluminum alloy cable is widely applied in the fields of civil construction and industrial and mining enterprises,especially in real estate,steel and metallurgy.

  6. Research progress of aluminum alloy automotive sheet and application technology

    Institute of Scientific and Technical Information of China (English)

    Ma Mingtu; You Jianghai; Lu Hongzhou; Wang Zhiwen

    2012-01-01

    Pretrcatment technology is deeply discussed to explain its importance in guaranteeing properties and form- ability of aluminum alloy automotive sheet. Some typical applications of aluminum alloy automotive sheet to automotive industry are listed. Based on the author's knowledge and recognition and research progress presently, the important re- search contents about aluminum alloy automotive sheet are emphasized. Reducing cost and price of sheet and going deeply into application research are the main work for expending the application of aluminum alloy automotive sheet in the automobile.

  7. Technique of Aluminum Alloy Composite by Inversion Casting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of the temperature of liquid aluminum alloy, the dipping time in liquid alloy and the thickness of base strips on the solidified layer was studied during the process of producing aluminum alloy composite strips used in automobile radiator with inversion casting. It is concluded that there is welding as well as diffusion of alloying elements between the base strip and the coating. Experiments proved that the interface has a good bonding.

  8. Microstructures and properties of aluminum die casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    M. M. Makhlouf; D. Apelian; L. Wang

    1998-10-01

    This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

  9. Modeling of Alternative Compositions of Recycled Wrought Aluminum Alloys

    Science.gov (United States)

    Kevorkijan, Varužan

    2013-08-01

    Nowadays, a significant part of postconsumed wrought aluminum scrap is still used for the production of comparatively cheaper cast alloys, in that way losing an important part of the potential added value. The share of postconsumed scrap in wrought aluminum alloys could be increased either by sorting to fractions with the required chemical composition and/or by broadening the standard compositional tolerance limits of alloying elements. The first solution requires hand or automatic sorting of postconsumed scrap as alloys or groups of alloys to the degree of separation sufficient to enable the blending of standard compositions of wrought alloys; the second solution is much more radical, predicting changes in the existing standards for wrought aluminum alloys toward nonstandard alloys but yet having properties acceptable for customers. In this case, the degree of separation of incoming postconsumed scrap required is much less demanding. The model presented in this work enables the design of optimal (standard and nonstandard recycling-friendly) compositions and properties of wrought aluminum alloys with significantly increased amounts of postconsumed scrap. The following two routes were modeled in detail: (I) the blending of standard and nonstandard compositions of wrought aluminum alloys starting from postconsumed aluminum scrap sorted to various degrees simulated by the model and (II) changing the initial standard composition of wrought aluminum alloys to nonstandard "recycling-friendly" ones, with broader concentration tolerance limits of alloying elements and without influencing the selected alloy properties, specified in advance. The applied algorithms were found to be very useful in the industrial design of both procedures: (I) the computation of the required chemical composition of the scrap streams obtained by sorting (or, in other words, the postconsumed scrap sorting level), necessary for achieving the standard wrought alloy composition and (II) the

  10. Research on Protection Against Contact Corrosion of 7050 Aluminum Alloy in Marine Atmosphere%7050铝合金在海洋大气中的接触腐蚀防护研究

    Institute of Scientific and Technical Information of China (English)

    王晴晴; 上官晓峰

    2013-01-01

    Outdoor atmospheric exposure tests of 7050 aluminum alloy were carried out in Hainan for 1 year. Unilateral tolerance factor method, probability and statistics T test, morphology observing, EDX,etc. were used to investigate the corrosion features and protective measures of 7050 aluminum alloy with different surface condition and different connective condition. The results show that the main corrosion of anodized 7050 aluminum alloy is the pitting initiation, especially concentrating in the joint between the 7050 aluminum alloy and TCI8 titanium alloy. From T test results, marine atmospheric corrosion plays an obvious role on fatigue life of 7050 aluminum alloy, whether samples painted and jointed or not. To some extent,painting and connection with glue can decrease the influence of atmospheric corrosion and galvanic corrosion on 7050 aluminum alloy.%通过在海南开展的7050铝合金为期1年的户外大气暴露试验,并利用单侧容限因数法、概率统计T检验、形貌观察和EDX等手段研究了不同表面状态、连接状态的7050铝合金在海洋大气环境中的腐蚀特征和防护措施.研究表明:表面阳极化处理的7050铝合金的腐蚀是以点蚀萌生为主,特别是在与TC18钛合金连接处腐蚀比较集中;从T检验的结果得知,无论7050铝合金涂漆与否、装配与否,海洋大气腐蚀对疲劳寿命都有显著影响;涂漆和胶结装配可在一定程度上降低大气腐蚀和电偶腐蚀对7050铝合金的影响.

  11. Precipitate-Accommodated Plasma Nitriding for Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Patama Visittipitukul; Tatsuhiko Aizawa; Hideyuki Kuwahara

    2004-01-01

    Reliable surface treatment has been explored to improve the strength and wear resistance of aluminum alloy parts in automotives. Long duration time as well as long pre-sputtering time are required for plasma nitriding of aluminum or its alloys only with the thickness of a few micrometers. New plasma inner nitriding is proposed to realize the fast-rate nitriding of aluminum alloys. Al-6Cu alloy is employed as a targeting material in order to demonstrate the effectiveness of this plasma nitriding. Mechanism of fast-rate nitriding process is discussed with consideration of the role of Al2Cu precipitates.

  12. The Elastic Constants for Wrought Aluminum Alloys

    Science.gov (United States)

    Templin, R L; Hartmann, E C

    1945-01-01

    There are several constants which have been devised as numerical representations of the behavior of metals under the action of loadings which stress the metal within the range of elastic action. Some of these constants, such as Young's modulus of elasticity in tension and compression, shearing modulus of elasticity, and Poisson's ratio, are regularly used in engineering calculations. Precise tests and experience indicate that these elastic constants are practically unaffected by many of the factors which influence the other mechanical properties of materials and that a few careful determinations under properly controlled conditions are more useful and reliable than many determinations made under less favorable conditions. It is the purpose of this paper to outline the methods employed by the Aluminum Research Laboratories for the determination of some of these elastic constants, to list the values that have been determined for some of the wrought aluminum alloys, and to indicate the variations in the values that may be expected for some of the commercial products of these alloys.

  13. Fabrication of super-hydrophobic surfaces on aluminum alloy substrates by RF-sputtered polytetrafluoroethylene coatings

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2014-03-01

    Full Text Available In this work, we present a method of fabricating super-hydrophobic surface on aluminum alloy substrate. The etching of aluminum surfaces has been performed using Beck's dislocation etchant for different time to create micrometer-sized irregular steps. An optimised etching time of 50 s is found to be essential before polytetrafluoroethylene (PTFE coating, to obtain a highest water contact angle of 165±2° with a lowest contact angle hysteresis as low as 5±2°. The presence of patterned microstructure as revealed by scanning electron microscopy (SEM together with the low surface energy ultrathin RF-sputtered PTFE films renders the aluminum alloy surfaces highly super-hydrophobic.

  14. Gas-tungsten arc welding of aluminum alloys

    Science.gov (United States)

    Frye, Lowell D.

    1984-01-01

    A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  15. INSULATING CERAMIC INSERTS FOR CASTING PRODUCTS FROM ALUMINUM ALLOYS

    OpenAIRE

    2015-01-01

    The paper analyses production of reusable ceramic insulating inserts applied in permanent mold casting of aluminum alloys. It presents results of manufacturing of ceramic products from synthesized materials based on wollastonite, secondary grog, aluminum slag, etc. The paper demonstrates prospects of their applying.

  16. INSULATING CERAMIC INSERTS FOR CASTING PRODUCTS FROM ALUMINUM ALLOYS

    Directory of Open Access Journals (Sweden)

    A. T. Volochko

    2015-01-01

    Full Text Available The paper analyses production of reusable ceramic insulating inserts applied in permanent mold casting of aluminum alloys. It presents results of manufacturing of ceramic products from synthesized materials based on wollastonite, secondary grog, aluminum slag, etc. The paper demonstrates prospects of their applying.

  17. Wear resistance analysis of the aluminum 7075 alloy and the nanostructured aluminum 7075 - silver nanoparticles composites

    Directory of Open Access Journals (Sweden)

    Estrada-Ruiz R.H.

    2016-01-01

    Full Text Available Nanostructured composites of the aluminum 7075 alloy and carbon-coated silver nanoparticles were synthetized by the mechanical milling technique using a high-energy mill SPEX 8000M; the powders generated were compacted, sintered and hot-extruded to produce 1 cm-diameter bars. The composites were then subjected to a wear test using a pin-on-disc device to validate the hypothesis that second phase-ductile nanometric particles homogenously distributed throughout the metalmatrix improve the wear resistance of the material. It was found that silver nanoparticles prevent the wear of the material by acting as an obstacle to dislocations movement during the plastic deformation of the contact surface, as well as a solid lubricant when these are separated from the metal-matrix.

  18. Selection of crucible oxides in molten titanium and titanium aluminum alloys by thermo-chemistry calculations

    Directory of Open Access Journals (Sweden)

    Kostov A.

    2005-01-01

    Full Text Available Titanium and its alloys interstitially dissolve a large amount of impurities such as oxygen and nitrogen, which degrade the mechanical and physical properties of alloys. On the other hand crucible oxides based on CaO, ZrO2 Y2O3, etc., and their spinels (combination of two or more oxides can be used for melting titanium and its alloys. However, the thermodynamic behavior of calcium, zirconium, yttrium on the one side, and oxygen on the other side, in molten Ti and Ti-Al alloys have not been made clear and because of that, it is very interesting for research. Owing of literature data, as well as these crucibles are cheaper than standard crucibles for melting titanium and titanium alloys, in this paper will be presented the results of selection of thermo-chemistry analysis with the aim to determine the crucible oxide stability in contact with molten titanium and titanium-aluminum alloys.

  19. High Speed Twin Roll Casting of Aluminum Alloy Strips

    Institute of Scientific and Technical Information of China (English)

    Toshio; Haga

    2002-01-01

    The twin roll caster for aluminum alloys has many a dv antages. For example, rapid solidification, low equipment cost, and low running cost, etc. However, the twin roll caster has some disadvantages. They are slow c asting speed and limitation of alloys. In the conventional twin roll caster, the casting speed is slower than 10 m/min. Aluminum alloys, which freezing range is wide, can not be cast. In the present study, break through of these problems wa s tried, and a new type twin roll caster was devised...

  20. Microstructure Development and Characteristics of Semisolid Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Merton Flemings; srinath Viswanathan

    2001-05-15

    A drop forge viscometer was employed to investigate the flow behavior under very rapid compression rates of A357, A356 diluted with pure aluminum and Al-4.5%Cu alloys. The A357 alloys were of commercial origin (MHD and SIMA) and the rheocast, modified A356 and Al-4.5Cu alloys were produced by a process developed at the solidification laboratory of MIT.

  1. Particulate and gaseous emissions when welding aluminum alloys.

    Science.gov (United States)

    Cole, Homer; Epstein, Seymour; Peace, Jon

    2007-09-01

    Fabrication and repair of aluminum components and structures commonly involves the use of electric arc welding. The interaction of the arc and the metal being welded generates ultraviolet radiation, metallic oxides, fumes, and gases. Aluminum is seldom used as the pure metal but is often alloyed with other metals to improve strength and other physical properties. Therefore, the exact composition of any emissions will depend on the welding process and the particular aluminum alloy being welded. To quantify such emissions, The Aluminum Association sponsored several studies to characterize arc welding emissions by the gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) processes for various combinations of base and filler alloys. In all cases, the tests were conducted under conditions that could be found in a production weld shop without forced ventilation. The concentrations of each analyte that a welder could be exposed to were greatly affected by the welding process, the composition of the base and filler alloys, the position of the welder, and the welding helmet. The results obtained can be used by employers to identify and control potential hazards associated with the welding of aluminum alloys and can provide the basis for hazard communication to employees involved in the welding of these alloys.

  2. Preparation of cast aluminum alloy-mica particle composites

    Science.gov (United States)

    Deonath, MR.; Bhat, R. T.; Rohatgi, P. K.

    1980-01-01

    A method for making aluminum-mica particle composites is presented in which mica particles are stirred in molten aluminum alloys followed by casting in permanent molds. Magnesium is added either as an alloying element or in the form of pieces to the surface of the alloy melts to disperse up to 3 wt% mica powders in the melts and to obtain high recoveries of mica in the castings. The mechanical properties of the aluminum alloy-mica composite decrease with increasing mica content; however, even at 2.2% it has a tensile strength of 14.22 kg/sq mm with 1.1% elongation, a compression strength of 42.61 kg/sq mm, and an impact strength of 0.30 kgm/sq cm. Cryogenic and self-lubricating bearing are mentioned applications.

  3. CORROSION RESISTANCE OF ALUMINUM CANS IN CONTACT WITH BEER

    Directory of Open Access Journals (Sweden)

    Luiza Esteves

    2015-07-01

    Full Text Available Aluminum cans with an organic coating are used in Brazil as packaging for carbonated beverages (soft drinks, beer, which act as electrolyte solutions. These electrolytes, in contact with the inner metal can, initiate a corrosion process of aluminum. The presence of metallic ions can change the flavor of the beverage, compromising the product quality. This work aims to evaluate the corrosion resistance of aluminum in beer environment using the technique of Electrochemical Impedance Spectroscopy (EIS. The Scanning Electron Microscopy (SEM and the Energy Dispersive Spectroscopy (EDS were used to evaluate the metal surface. Two batches with different coating thickness were analyzed for the same date of manufacture. The electrolyte resistance and the aluminum charge transfer resistance in beer varied depending on the batch analyzed.

  4. Chemical Degradation of the Cathodic Electrical Contact Between Carbon and Cast Iron in Aluminum Production Cells

    Science.gov (United States)

    Brassard, Martin; Désilets, Martin; Soucy, Gervais; Bilodeau, Jean-François; Forté, Martin

    2017-02-01

    The cathodic carbon to cast iron electrical contact degradation is one of the factors to consider in the cathode voltage drop (CVD) increase over the lifetime of aluminum production cells. Lab-scale experiments were carried out to study the cast iron to carbon interface chemical degradation and the impact of important cell parameters like temperature and bath chemistry. Laboratory degradation results were compared with industrial samples. A thermoelectric Ansys numerical model was then used to predict the effect of cast iron surface degradation over CVD. Results show that the aluminum formation on the cast iron surface and its subsequent diffusion creates an immiscible mixture of Fe-Al metal alloy and electrolytic bath. Disparities were also observed between industrial samples taken from two different technologies, suggesting that the degradation can be slowed down. Thermoelectric calculations finally revealed that the impact of the contact resistance augmentation is by far greater than the cast iron degradation.

  5. Synthesis of aluminum-based scandium-yttrium master alloys

    Science.gov (United States)

    Bazhin, V. Yu.; Kosov, Ya. I.; Lobacheva, O. L.; Dzhevaga, N. V.

    2015-07-01

    The preparation technology for an Al-2% Sc-0.5% Y master alloy using aluminum-manganese alloys has been developed and tested. The microstructure of the prepared master alloy is studied and the compositions of intermetallics is determined. The efficient technological parameters of the synthesis are determined. It is shown that varying the compositions of starting reagents and alloying additions and optimizing the process conditions (temperature, mixing, etc.) allow us to forecast the manufacturing and operating characteristics of aluminum-based master alloys. Joint additions of scandium and yttrium oxides to a charge favor a substantial decrease in the grain size of the formed intermetallics; this effect appears to the utmost in the case of microallying with yttrium up to 0.5 wt %.

  6. China’s Aluminum Alloy Die Castings Industry has Promising Prospects

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>Engine aluminum alloy engine block die casting experienced rapid development in recent years. Domestic enterprises introduced large die casting machine automatic production lines, and developed large aluminum alloy die cast-

  7. Aluminum for bonding Si-Ge alloys to graphite

    Science.gov (United States)

    Eggemann, Robert V.

    1976-01-13

    Improved thermoelectric device and process, comprising the high-temperature, vacuum bonding of a graphite contact and silicon-germanium thermoelectric element by the use of a low void, aluminum, metallurgical shim with low electrical resistance sandwiched therebetween.

  8. 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

  9. Experimental study on activating welding for aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Huang Yong; Fan Ding

    2005-01-01

    TIG welding and EB welding for aluminum alloy 3003 were carried out to study the effects of activating flux on weld penetration of activating welding for aluminum alloys. SiO2 was used as the activating flux. It is found that, SiO2 can increase the weld penetration and decrease the weld width of FBTIG when the flux gap is small. For A-TIG welding and EB welding with focused mode, the weld penetrations and the weld widths increase simultaneously. SiO2 has little effect on the weld penetration and weld width of EB welding with defocused mode. It is believed that, change of surface tension temperature gradient is not the main mechanism of SiO2 improving weld penetration of activating welding for aluminum alloys.

  10. Microstructural evolution of aluminum alloy 3003 during annealing

    Institute of Scientific and Technical Information of China (English)

    WU Wen-xiang; ZHANG Xin-ming; SUN De-qin; HU Guo-qiang; LIU Guo-jin

    2006-01-01

    The microstructural evolution of cold-rolled aluminum alloy 3003 during annealing was investigated by means of micro-hardness measurement, electrical resistivity measurement, optical microscopy and transmission electron microscopy. The interaction of recrystallization and precipitation of aluminum alloy 3003 was also discussed. The results show that the recrystallized grain size of cold-rolled aluminum alloy 3003 is strongly affected by precipitation during annealing. When precipitation occurs prior to recrystallization at low temperature(300 ℃), the grain structure becomes coarse, and the precipitation process is affected by the presence of lattice defects, i.e. high cold reduction results in a large number of precipitates. When annealing at 500 ℃, however, for the recrystallization is prior to precipitation, the precipitation is independent of cold deformation reduction and a fine, equiaxed grain structure is obtained.

  11. Comments on process of duplex coatings on aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

    2004-01-01

    Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

  12. Corrosion of an aluminum alloy chilled in flowing seawater and the effect of cathodic prevention

    OpenAIRE

    Yabuki, Akihiro; Yasunaga, David T.; Shibutani, Toshihiro; Shinkai, Koichi

    2007-01-01

    A new type of jet-in-slit testing apparatus for a specimen, chilled with a peltier element, was developed to investigate corrosion on the heat transfer surface of an aluminum alloy heat exchanger, in contact with a liquefaction gas at cryogenic temperature and in flowing seawater. The specimen can be chilled, even under flowing conditions, using this apparatus. Corrosion tests and polarization measurements of a specimen chilled by a peltier element were carried out in flowing seawater at vari...

  13. Measurements of interfacial thermal contact conductance between pressed alloys at low temperatures

    Science.gov (United States)

    Zheng, Jiang; Li, Yanzhong; Chen, Pengwei; Yin, Geyuan; Luo, Huaihua

    2016-12-01

    Interfacial thermal contact conductance is the primary factor limiting the heat transfer in many cryogenic engineering applications. This paper presents an experimental apparatus to measure interfacial thermal contact conductance between pressed alloys in a vacuum environment at low temperatures. The measurements of thermal contact conductance between pressed alloys are conducted by using the developed apparatus. The results show that the contact conductance increases with the decrease of surface roughness, the increase of interface temperature and contact pressure. The temperature dependence of thermal conductivity and mechanical properties is analyzed to explain the results. Thermal contact conductance of a pair of stainless steel specimens is obtained in the interface temperature range of 135-245 K and in the contact pressure range of 1-9 MPa. The results are regressed as a power function of temperature and load. Thermal conductance is also obtained between aluminums as well as between stainless steel and aluminum. The load exponents of the regressed relations for different contacts are compared. Existing theoretical models (the Cooper-Mikic-Yovanovich plastic model, the Mikic elastic model and the improved Kimura model) are reviewed and compared with the experimental results. The Cooper-Mikic-Yovanovich model predictions are found to be in good agreement with experimental results, especially with measurements between aluminums.

  14. Improved thermal treatment of aluminum alloy 7075

    Science.gov (United States)

    Cocks, F. H.

    1968-01-01

    Newly developed tempering treatment considerably increases the corrosion resistance of 7075-T6 alloy and concomitantly preserves its yield strength. The results of tests on samples of the alloy subjected to the above treatments show that when the overaging period is 12 hours /at 325 degrees F/, the alloy exhibits a yield strength of 73,000 psi.

  15. Forming analysis and application for aluminum-alloy material

    Institute of Scientific and Technical Information of China (English)

    Wei Yuansheng

    2012-01-01

    The increase in car ownership brought about by energy shortages, and environmental crises became more acute. The most effective way to achieve energy saving and emission reduction of car is to improve engine efficiency. In addition to that, lightweight body is the key. Aluminum, magnesium alloy as significant materials of lightweight, and the application amount in the car body is a significant upward trend. However, there is high cost of material, with im- mature applied technology and a series of bottleneck problems. All of them affect general application of lightweight mate- rials. This paper focuses on forming process issues for aluminum, magnesium alloy and the solutions to achieve.

  16. Thermodynamics of Titanium-Aluminum-Oxygen Alloys Studied

    Science.gov (United States)

    Copland, Evan H.; Jacobson, Nathan S.

    2001-01-01

    Titanium-aluminum alloys are promising intermediate-temperature alloys for possible compressor applications in gas-turbine engines. These materials are based on the a2-Ti3Al + g-TiAl phases. The major issue with these materials is high oxygen solubility in a2-Ti3Al, and oxidation of unsaturated alloys generally leads to mixed non-protective TiO2+Al2O3 scales. From phase diagram studies, oxygen saturated a2-Ti3Al(O) is in equilibrium with Al2O3; however, oxygen dissolution has a detrimental effect on mechanical properties and cannot be accepted. To better understand the effect of oxygen dissolution, we examined the thermodynamics of titanium-aluminum-oxygen alloys.

  17. 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.

  18. The Examination of the Aluminum Alloy 7017 as a Replacement for the Aluminum Alloy 7039 in Lightweight Armor Systems

    Science.gov (United States)

    2016-07-01

    any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters...ELEMENT NUMBER 6. AUTHOR(S) Tyrone L Jones and Brian E Placzankis 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING...ABSTRACT The aluminum alloy (AA) 7039 has been recognized as a serviceable armor plate alloy for years. However, the inherent stress corrosion

  19. Titanium-zirconium-phosphonate hybrid film on 6061 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Shuanghong WANG; Lei WANG; Changsheng LIU

    2011-01-01

    Three titanium-zirconium-phosphonate hybrid films were formed on AA6061 aluminum alloy by immersing in fluorotitanic acid and fluorozirconic acid based solution containing different phosphonic acids for protective coatings of aluminium alloy. The corrosion resistance of three hybrid films as the substitute for chromate film were evaluated and compared. The neutral salt spray test was explored,the immersion test was conducted and electrochemical test was also executed. The hybrid films exhibited well-pleasing corrosion resistance and adhesion to epoxy resin paints. It was found out that the hybrid films could efficiently be a substitute for chromate based primer over aluminium alloy.

  20. Oxidation resistant, thoria-dispersed nickel-chromium-aluminum alloy

    Science.gov (United States)

    Baranow, S.; Klingler, L. J.

    1973-01-01

    Modified thoria-dispersed nickel-chromium alloy has been developed that exhibits greatly improved resistance to high-temperature oxidation. Additions of aluminum have been made to change nature of protective oxide scale entirely and to essentially inhibit oxidation at temperatures up to 1260 C.

  1. Materials Design for Joinable, High Performance Aluminum Alloys

    Science.gov (United States)

    Glamm, Ryan James

    An aluminum alloy compatible with friction stir welding is designed for automotive and aerospace structural applications. Current weldable automotive aluminum alloys do not possess the necessary strength to meet safety standards and therefore are not able to replace steel in the automotive body. Significant weight savings could be achieved if steel components are replaced with aluminum. Current aerospace alloys are not weldable, requiring machining of large pieces that are then riveted together. If an aerospace alloy could be friction stir welded, smaller pieces could be welded, reducing material waste. Using a systems approach for materials design, property goals are set from performance objectives. From previous research and computational predictions, a structure is designed for a prototype alloy containing dynamic precipitates to readily dissolve and re-precipitate and high stability precipitates to resist dissolution and coarsening in the weld region. It is found that a Ag modified Al-3.9Mg-0.04Cu (at. %) alloy enhanced the rate and magnitude of hardening during ageing, both beneficial effects for dynamic precipitation. In the same alloy, ageing at 350°C results in hardening from Al 3(Sc,Zr) precipitates. Efforts to effectively precipitate both populations simultaneously are unsuccessful. The Al3(Sc,Zr) precipitation hardened prototype is friction stir processed and no weak zones are found in the weld hardness profile. An aerospace alloy design is proposed, utilizing the dual precipitate structure shown in the prototype. The automotive alloy is designed using a basic strength model with parameters determined from the initial prototype alloy analysis. After ageing to different conditions, the alloy is put through a simulated heat affected zone thermal cycle with a computer controlled induction heater. The aged samples lose hardness from the weld cycle but recover hardness from a post weld heat treatment. Atom probe tomography and transmission electron

  2. Creep Aging Behavior Characterization of 2219 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Lingfeng Liu

    2016-06-01

    Full Text Available In order to characterize the creep behaviors of 2219 aluminum alloy at different temperatures and stress levels, a RWS-50 Electronic Creep Testing Machine (Zhuhai SUST Electrical Equipment Company, Zhuhai, China was used for creep experiment at temperatures of 353~458 k and experimental stresses of 130~170 MPa. It was discovered that this alloy displayed classical creep curve characteristics in its creep behaviors within the experimental parameters, and its creep value increased with temperature and stress. Based on the creep equation of hyperbolic sine function, regression analysis was conducted of experimental data to calculate stress exponent, creep activation energy, and other related variables, and a 2219 aluminum alloy creep constitutive equation was established. Results of further analysis of the creep mechanism of the alloy at different temperatures indicated that the creep mechanism of 2219 aluminum alloy differed at different temperatures; and creek characteristics were presented in three stages at different temperatures, i.e., the grain boundary sliding creep mechanism at a low temperature stage (T < 373 K, the dislocation glide creep mechanism at a medium temperature stage (373 K ≤ T < 418 K, and the dislocation climb creep mechanism at a high temperature stage (T ≥ 418 K. By comparative analysis of the fitting results and experiment data, they were found to be in agreement with the experimental data, revealing that the established creep constitutive equation is suitable for different temperatures and stresses.

  3. Development Program for Natural Aging Aluminum Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Geoffrey K. Sigworth

    2004-05-14

    A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

  4. Cleavage crystallography of liquid metal embrittled aluminum alloys

    Science.gov (United States)

    Reynolds, A. P.; Stoner, G. E.

    1991-01-01

    The crystallography of liquid metal-induced transgranular cleavage in six aluminum alloys having a variety of microstructures has been determined via Laue X-ray back reflection. The cleavage crystallography was independent of alloy microstructure, and the cleavage plane was 100-plane oriented in all cases. It was further determined that the cleavage crystallography was not influenced by alloy texture. Examination of the fracture surface indicated that there was not a unique direction of crack propagation. In addition, the existence of 100-plane cleavage on alloy 2024 fracture surfaces was inferred by comparison of secondary cleavage crack intersection geometry on the 2024 surfaces with the geometry of secondary cleavage crack intersections on the test alloys.

  5. Optimum parameters for wetting and pressureless infiltration of silicon carbide preforms by aluminum alloys

    Science.gov (United States)

    Pech-Canul, Martin Ignacio

    The effect of processing parameters on the wetting of SiC by molten aluminum and the pressureless infiltration of SiCp preforms by aluminum alloys has been investigated. The effect of magnesium and silicon additions to aluminum, free silicon on the SiC substrate, nitrogen gas in the atmosphere, and process temperature on the wetting characteristics of SiC by aluminum alloys was investigated using the sessile drop technique. The contribution of each of these parameters and their interactions to the contact angle, surface tension, and driving force for wetting were determined via an L8 Taguchi experiment and analysis of variance (ANOVA). In addition, an optimized process for enhanced wetting is suggested and validated. The process parameters under which optimum wetting of SiC by Al was obtained were used to infiltrate SiCp preforms with Al without the use of pressure. The effect of SiC particle size, infiltration time, preform height, vol. % SiC in the preform, and Si coating on the SiC particles on the pressureless infiltration of SiCp compacts with aluminum was investigated and quantified via a Taguchi experiment and ANOVA. The contribution of each of these parameters and their interactions to the density, modulus of elasticity, and modulus of rupture of the composites were determined. Processing conditions for obtaining optimum density, modulus of rupture and modulus of elasticity were projected. The projected modulus of elasticity obtainable under optimum processing conditions was validated experimentally. A mechanism is proposed to explain the beneficial role that the interaction of nitrogen with magnesium plays in enhancing wetting. The role of silicon in wetting and pressureless infiltration of SiCp preforms by aluminum alloys is explained.

  6. Deformation and Damage of Two Aluminum Alloys from Ballistic Impact

    Science.gov (United States)

    Anderson, Charles E., Jr.; Dannemann, Kathryn A.

    2002-07-01

    A series of impact experiments were conducted on 4.76-mm-thick aluminum plates to investigate the deformation and damage behavior of two aluminum alloys, 6061-T6 and 7075-T6. The Sierra 165 lead-filled bullet was used to load the plates. Impact velocities were varied from approximately 260 m/s to 370 m/s. The flow stress for 7075-T6 aluminum is approximately twice that for 6061-T6 aluminum; however, the ballistic limit velocities differ by only 10%. The 7075-T6 aluminum plates exhibit less deformation than the 6061-T6 plates at the same impact velocity, but at some critical velocity, a through-thickness crack appears in the 7075-T6 plate, ultimately leading to plate perforation. In contrast, the 6061-T6 plates continue to deform and fail by ductile tearing. These differences in damage/failure result in the two alloys having much closer ballistic limit velocities than expected based on differences in strength.

  7. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  8. Aluminum-lithium alloy development for thixoforming

    Energy Technology Data Exchange (ETDEWEB)

    Sauermann, R.; Friedrich, B. [IME Process Metallurgy and Metal Recycling, RWTH Aachen Univ. (Germany); Puettgen, W.; Bleck, W. [IEHK Inst. for Ferrous Metallurgy, RWTH Aachen Univ. (Germany); Balitchev, E.; Hallstedt, B.; Schneider, J.M. [MCh Materials Chemistry, RWTH Aachen Univ. (Germany); Bramann, H.; Buehrig-Polaczek, A. [GI Foundry Inst., RWTH Aachen Univ. (Germany); Uggowitzer, P.J. [ETH Zuerich, Metal Physics and Technology (Germany)

    2004-12-01

    This paper presents a scientific contribution to the development of lightweight/high-performance Al-Li alloys suitable for semi-solid processing. Thermodynamic calculations identified the most promising compositions with focus on the solidus-liquidus interval, fraction of solid-versus-temperature and phase reactions. The synthesis of Al-Li precursor billets was performed by overpressure induction melting in controlled atmosphere. DTA and microstructure investigations on Al-Li specimens were carried out as well as thixocasting trials of demonstrator components. New rheocasting of Al-Li alloys was investigated to identify the potential of this alternative precursor material route. It is shown that specifically developed Al-Li alloys offer great potential for semi-solid manufacturing. (orig.)

  9. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    Science.gov (United States)

    Ray, R.

    1984-01-01

    Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

  10. Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis.

    Science.gov (United States)

    Hozumi, Atsushi; McCarthy, Thomas J

    2010-02-16

    Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis for probe liquids were prepared by chemical vapor deposition (CVD) of bis((tridecafluoro-1,1,2,2,-tetrahydrooctyl)-dimethylsiloxy)methylsilane (CF(3)(CF(2))(5)CH(2)CH(2)Si(CH(3))(2)O)(2)SiCH(3)H, (R(F)Si(Me)(2)O)(2)SiMeH). Oxidized aluminum surfaces were prepared by photooxidation/cleaning of sputter-coated aluminum on silicon wafers (Si/Al(Al(2)(O(3)))) using oxygen plasma. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that this facile CVD method produces a monolayer with a thickness of 1.1 nm on the Si/Al(Al(2)(O(3))) surface without a discernible change in surface morphology. After monolayer deposition, the hydrophilic Si/Al(Al(2)(O(3))) surface became both hydrophobic and oleophobic and exhibited essentially no contact angle hysteresis for water and n-hexadecane (advancing/receding contact angles (theta(A)/theta(R)) = 110 degrees/109 degrees and 52 degrees/50 degrees, respectively). Droplets move very easily on this surface and roll off of slightly tilted surfaces, independently of the contact angle (which is a practical definition of ultralyophobic). A conventional fluoroalkylsilane monolayer was also prepared from 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CF(3)(CF(2))(7)CH(2)CH(2)Si(OCH(3))(3), R(F)Si(OMe)(3)) for comparison. The theta(A)/theta(R) values for water and n-hexadecane are 121 degrees/106 degrees and 76 degrees/71 degrees, respectively. The larger hysteresis values indicate the "pinning" of probe liquids, even though advancing contact angles are larger than those of the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers. The (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers have excellent hydrolytic stability in water. We propose that the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers are flexible and liquidlike and that drops in contact with these surfaces experience very low energy barriers between metastable states, leading to the

  11. Overheating temperature of 7B04 high strength aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    GAO Feng-hua; LI Nian-kui; TIAN Ni; SUN Qiang; LIU Xian-dong; ZHAO Gang

    2008-01-01

    The microstructure and overheating characteristics of the direct chill semicontinuous casting ingot of 7B04 high strength aluminum alloy, and those after industrial homogenization treatment and multi-stage homogenization treatments, were studied by differential scanning calorimetry(DSC), optical microscopy(OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy(SEM-EDX). The results show that the microstructure of direct chill semicontinuous casting ingot of the 7B04 alloy contains a large number of constituents in the form of dendritic networks that consist of nonequilibrium eutectic and Fe-containing phases. The nonequilibrium eutectic contains Al, Zn, Mg and Cu, and the Fe-containing phases include two kinds of phases, one containing Al, Fe, Mn and Cu, and the other having Al, Fe, Mn, Cr, Si and Cu. The melting point of the nonequilibrium eutectic is 478 ℃ for the casting ingot of the 7B04 alloy which is usually considered as its overheating temperature. During industrial homogenization treatment processing at 470 ℃, the nonequilibrium eutectic dissolves into the matrix of this alloy partly, and the remainder transforms into Al2CuMg phase that cannot be dissolved into the matrix at that temperature completely. The melting point of the Al2CuMg phase which can dissolve into the matrix completely by slow heating is about 490 ℃. The overheating temperature of this high strength aluminum alloy can rise to 500-520 ℃. By means of special multi-stage homogenization, the temperature of the homogenization treatment of the ingot of the 7B04 high strength aluminum alloy can reach 500 ℃ without overheating.

  12. Investigation of the Precipitation Behavior in Aluminum Based Alloys

    KAUST Repository

    Khushaim, Muna S.

    2015-11-30

    The transportation industries are constantly striving to achieve minimum weight to cut fuel consumption and improve overall performance. Different innovative design strategies have been placed and directed toward weight saving combined with good mechanical behavior. Among different materials, aluminum-based alloys play a key role in modern engineering and are widely used in construction components because of their light weight and superior mechanical properties. Introduction of different nano-structure features can improve the service and the physical properties of such alloys. For intelligent microstructure design in the complex Al-based alloy, it is important to gain a deep physical understanding of the correlation between the microstructure and macroscopic properties, and thus atom probe tomography with its exceptional capabilities of spatially resolution and quantitative chemical analyses is presented as a sophisticated analytical tool to elucidate the underlying process of precipitation phenomena in aluminum alloys. A complete study examining the influence of common industrial heat treatment on the precipitation kinetics and phase transformations of complex aluminum alloy is performed. The qualitative evaluation results of the precipitation kinetics and phase transformation as functions of the heat treatment conditions are translated to engineer a complex aluminum alloy. The study demonstrates the ability to construct a robust microstructure with an excellent hardness behavior by applying a low-energy-consumption, cost-effective method. The proposed strategy to engineer complex aluminum alloys is based on both mechanical strategy and intelligent microstructural design. An intelligent microstructural design requires an investigation of the different strengthen phases, such as T1 (Al2CuLi), θ′(Al2Cu), β′(Al3Zr) and δ′(Al3Li). Therefore, the early stage of phase decomposition is examined in different binary Al-Li and Al-Cu alloys together with different

  13. Friction and wear of titanium alloys and copper alloys sliding against titanium 6-percent-aluminum - 4-percent-vanadium alloy in air at 430 C

    Science.gov (United States)

    Wisander, D. W.

    1976-01-01

    Experiments were conducted to determine the friction and wear characteristics of aluminum bronzes and copper-tin, titanium-tin, and copper-silver alloys sliding against a titanium-6% aluminum-4% vanadium alloy (Ti-6Al-4V). Hemispherically tipped riders of aluminum bronze and the titanium and copper alloys were run against Ti-6Al-4V disks in air at 430 C. The sliding velocity was 13 cm/sec, and the load was 250 g. Results revealed that high tin content titanium and copper alloys underwent significantly less wear and galling than commonly used aluminum bronzes. Also friction force was less erratic than with the aluminum bronzes.

  14. Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Patricija Kavaliauskaitė

    2016-04-01

    Full Text Available The article examines plasma sprayed 95Ni-5Al coatings on alu-minum-magnesium (Mg ≈ 2,6‒3,6 % alloy substrate. Alumi-num-magnesium samples prior spraying were prepared with mechanical treatment (blasting with Al2O3. 95Ni-5Al coatings on aluminum-magnesium alloys were sprayed with different parameters of process and coating‘s thickness, porosity, micro-hardness and microstructure were evaluated. Also numerical simulations in electric and magnetic phenomena of plasma spray-ing were carried out.

  15. A Positron Annihilation Study of Corrosion of Aluminum and Aluminum Alloy by NaOH

    Science.gov (United States)

    Wu, Y. C.; Zhai, T.; Coleman, P. G.

    2012-08-01

    Corrosion of fully-annealed pure aluminum and a continuous-cast AA2037 aluminum alloy (solutionized and water quenched) in a 1M NaOH solution for various periods of time were analyzed with positron beam-based Doppler broadening spectroscopy. By varying the energy of the incident positron beam, corrosion-induced defects at different depths from the surface were detected. It was found that the Doppler-broadened annihilation line-width parameter was significantly increased near the surface of pure aluminum after corrosion, probably due to the interaction between positrons and nanometer-sized voids formed near the aluminum surface during corrosion. Examination by atomic force microscopy indicated that many pits were formed on the aluminum surface after corrosion. In contrast, a significant decrease in the line-width parameter was observed in AA2037 alloy after corrosion and interpreted as being caused by copper enrichment at the metal-oxide interface during corrosion; such enrichment at large cavity sites was confirmed by energy dispersion spectrometry.

  16. Residual stress profiling of an aluminum alloy by laser ultrasonics

    Institute of Scientific and Technical Information of China (English)

    PAN Yondong; QIAN Menglu; XU Weijiang; M. OURAK

    2004-01-01

    A residual-stress profile along the thickness of an aluminum alloy sheet is determined by laser-ultrasonic technique. Surface acoustic waves are generated by a Nd:YAG pulse laser and detected by a Heterodyne interferometer on a lateral free surface of the sheet. The distribution of residual stress is determined by measuring the relative variation of the wavevelocities at different location of the sample along its thickness. This technique is validated by three different residual stress profiles obtained experimentally.

  17. Die Casting Mold Design for Aluminum Alloy Shell of Instrument

    Directory of Open Access Journals (Sweden)

    Li Yuanyuan

    2015-01-01

    Full Text Available This paper is about die casting mold design for aluminum alloy shell of instrument. Three-dimensional model of the casting and mold are designed by using Pro/Engineer and AutoCad which can analyze forming quality. Digital design and theoretical calculation can greatly shorten product development cycle and mold design cycle, improve the accuracy of product design and mold design, and reduce the cost of mold design.

  18. High speed twin roll caste for aluminum alloy thin strip

    Directory of Open Access Journals (Sweden)

    T. Haga

    2007-09-01

    Full Text Available Purpose: In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated.Design/methodology/approach: The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a bending test.Findings: A vertical type twin roll caster for strip casting of aluminum alloys was devised. The strip, which was thinner than 3 mm, could be cast at speeds higher than 60 m/min. Features of the twin roll casters are as below. Copper rolls were used and lubricant was not used in order to increase the casting speed. A casting nozzle was used to set the solidification length precisely. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Separating force was very small in order to prevent sticking of the strip to the roll. Low superheat casting was carried out in order to improve microstructure of the strip. In the present study, effectiveness of a high-speed and high-cooling rate twin roll caster of the present study for recycling aluminum alloy was investigated. Fe was added as impurity to 6063 and A356. The roll caster of the present study was useful to decrease the influence of impurity of Fe.Research limitations/implications: A high-speed twin roll caster of vertical type was designed and assembled to cast aluminum alloy thin strip.Originality/value: The results demonstrate that the high-speed twin roll caster can improve the deterioration by impurities.

  19. Microstructure characteristics and mechanical properties of rheocasting 7075 aluminum alloy

    OpenAIRE

    Yang Bin; Mao Weimin; Song Xiaojun

    2013-01-01

    The microstructure characteristics and mechanical properties of 7075 aluminum alloy produced by a new rheoforming technique, under as-cast and optimized heat treatment conditions, were investigated. The present rheoforming combined the innovatively developed rheocasting process, named as ICSPC (inverted cone-shaped pouring channel) process, and the existing HPDC (high pressure die casting) process. The experimental results show that the ICSPC can be used to prepare high quality semi-solid slu...

  20. Retrogression and reaging of 7075 T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fleck, P.; Calleros, D.; Madsen, M.; Trinh, T.; Hoang, D.; Foyos, J.; Es-Said, O.S. [Loyola Univ., Los Angeles, CA (United States). NSF Res. Experience for Undergraduates Program; Lee, E.W.

    2000-07-01

    The objective of this study was to investigate the feasibility of performing retrogression and reaging (RRA) heat treatments on 7075-T6 aluminum alloy in muffle furnaces instead of salt and oil baths. The retrogression temperatures were 180 C, 200 C, 220 C and 240 C and retrogression times were 5, 10, 15 and 25 minutes. Reaging was performed at 120 C for 24, 36 and 48 hours. Tensile testing, hardness and electrical resistivity measurements were determined. (orig.)

  1. Residual stress in quenched 7075 aluminum alloy thick plates

    Institute of Scientific and Technical Information of China (English)

    林高用; 张辉; 朱伟; 彭大暑; 梁轩; 周鸿章

    2003-01-01

    The influence of quenching water temperature, pre-stretching amount and aging temperature and times on residual stress in 7075 aluminum thick plate was studied by the measurement of residual stress using drilling hole method. The results indicate that residual stress decreases by 30% with increasing quenching water temperature from 40 ℃ to 80 ℃, 20% with increasing aging temperature from 100 ℃ to 180 ℃,and 20% with increasing aging times from 5 h to 25 h. Also, residual stress decreases to zero with increasing pre-stretching amount to approximately 2%. Hence, residual stress in 7075 aluminum thick plate is reduced by the control of quenching water temperature at 80 ℃ and with pre-stretching amount of about 2%. An optimal aging temperature and time should be systemically investigated to obtain combination of high mechanical performances and lower residual stress for manufacturing of 7075 aluminum alloy thick plates.

  2. Corrosion of Aluminum Alloys by IRFNA

    Science.gov (United States)

    1990-02-24

    and electropolishing and anodising, have been studied. aNeither had a significant long term effect on the corrosion rate of 2014 alumninium alloy in... steel spatula. (iv) The cell was assembled and raw eghed, the charge of galled Acid being determined by difference. Two additional bottom-working...The anodiuing solution was 1swt% sulphuric acid And the conditions were 25oC, 1 Mwm, 12V. The anodic oxide film waS scaled in delonised water (30

  3. Butt-welding Residual Stress of Heat Treatable Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    C.M. Cheng

    2007-01-01

    This study, taking three types of aluminum alloys 2024-T351, 6061-T6 and 7075-T6 as experimental materials, conducted single V-groove GTAW (gas tungsten arc welding) butt-welding to analyze and compare the magnitude and differences of residual stress in the three aluminum alloys at different single V-groove angles and in restrained or unrestrained conditions. The results show that the larger the grooving angle of butt joint, the higher the residual tensile stress. Too small grooving angle will lead to dramatic differences due to the amount of welding bead filler metal and pre-set joint geometry. Therefore, only an appropriate grooving angle can reduce residual stress. While welding, weldment in restrained condition will lead to a larger residual stress. Also, a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at equilibrium temperature. The higher the yield strength at equilibrium temperature, the higher the material residual stress. Because of its larger thermal conductivity, aluminum alloy test specimens have small temperature differential. Therefore, the residual tensile stress of all materials is lower than their yield strength.

  4. Solidification crack susceptibility of aluminum alloy weld metals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The susceptibilities of the three aluminum alloys to solidification crack were studied with trans-varestraint tests and tensile tests at elevated temperature. Their metallurgical characteristics, morphologies of the fractured surface and dynamic cracking behaviors at elevated temperature were analyzed with a series of micro-analysis methods. The results show that dynamic cracking models can be classified into three types. The first model has the healing effect which is called type A. The second is the one with deformation and breaking down of metal bridge, called type B. The last one is with the separation of liquid film along grain boundary, called type C.Moreover, the strain rate has different effects on crack susceptibility of aluminum alloys with different cracking models. ZL101 and 5083 alloys belong to type A and type C cracking model respectively, in which strain rate has greater effect on eutectic healing and plastic deformation of metal bridge. 6082 alloy is type B cracking model in which the strain rate has little effect on the deformation ability of the liquid film.

  5. Russian aluminum-lithium alloys for advanced reusable spacecraft

    Science.gov (United States)

    Charette, Ray O.; Leonard, Bruce G.; Bozich, William F.; Deamer, David A.

    1998-01-01

    Cryotanks that are cost-affordable, robust, fuel-compatible, and lighter weight than current aluminum design are needed to support next-generation launch system performance and operability goals. The Boeing (McDonnell Douglas Aerospace-MDA) and NASA's Delta Clipper-Experimental Program (DC-XA) flight demonstrator test bed vehicle provided the opportunity for technology transfer of Russia's extensive experience base with weight-efficient, highly weldable aluminum-lithium (Al-Li) alloys for cryogenic tank usage. As part of NASA's overall reusable launch vehicle (RLV) program to help provide technology and operations data for use in advanced RLVs, MDA contracted with the Russian Academy of Sciences (RAS/IMASH) for design, test, and delivery of 1460 Al-Li alloy liquid oxygen (LO2) cryotanks: one for development, one for ground tests, and one for DC-XA flight tests. This paper describes the development of Al-Li 1460 alloy for reusable LO2 tanks, including alloy composition tailoring, mechanical properties database, forming, welding, chemical milling, dissimilar metal joining, corrosion protection, completed tanks proof, and qualification testing. Mechanical properties of the parent and welded materials exceeded expectations, particularly the fracture toughness, which promise excellent reuse potential. The LO2 cryotank was successfully demonstrated in DC-XA flight tests.

  6. FORMABILITY OF THIN SHEETS FROM ALUMINUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Emil Spišák

    2016-12-01

    Full Text Available In this contribution there have been evaluated properties of four types of sheets made from aluminium alloys. In the case of each of the examined sheets there has been checked its shearing ability via the influence of punch-die clearance change on the quality of blanking edge. Quality of blanking edge is characterized by a ratio of plastic zone height to the total thickness of the sheared material. Formability during the drawing process was measured with earring test. Results are presented by the earring coefficient (unequal height of the cups.

  7. Diffusion bonding of Al7075 alloy to titanium aluminum vanadate alloy

    Science.gov (United States)

    Alhazaa, Abdulaziz Nasser

    The aluminum alloy (Al7075) and titanium alloy (Ti-6Al-4V) are used in a variety of applications in the aerospace industry. However, the high cost of Ti-6Al-4V alloy has been a major factor which has limited its use and therefore, the ability to join Al7075 alloy to Ti-6Al-4V alloy can provide a product that is less costly, but retains the high strength and light weight properties necessary for the transport industry. However, the large difference in the physical properties between these two alloys prevents the use of conventional joining techniques such as fusion welding to join these dissimilar alloys. Therefore, the diffusion bonding technique was used to join Al7075 alloy to Ti-6Al-4V alloy with the objective of minimizing microstructural changes of the two alloys during the bonding process. In this thesis, solid state and liquid phase bonding processes were undertaken. Solid state bonding was employed without interlayers and was successful at 510°C and 7 MPa. The bond interface showed an absence of the oxides due to the dissolution of oxygen into the titanium solution. Bonds made using copper interlayers at a temperature sufficient enough to form eutectic liquid formation between copper and aluminum were produced. The intermetallics theta(Al2Cu), S(Al2CuMg) and T(Al2Mg3Zn3) were identified at the aluminum interface while Cu3Ti2 intermetallic was identified at the titanium interface. Bonds made using tin based alloys interlayers and copper coatings were successful and gave the highest shear strength. The eutectic formation on the Al7075 alloy was responsible for joint formation at the aluminum interface while the formation of Sn3Ti5 intermetallic was responsible for the joint formation at titanium interface. The corrosion rate of the bonds decreased with increasing bonding time for joints made using the tin based interlayer in 3% NaCl solution. However, the presence of copper within the joint increased the corrosion rate of the bonds and this was attributed to

  8. Mechanical properties of hot rolled 2519 aluminum alloy plate

    Institute of Scientific and Technical Information of China (English)

    彭大暑; 陈险峰; 林启权; 张辉

    2003-01-01

    The effects of differences of temper on mechanical properties of T6, T7 and T8 plates of aluminum alloy 2519 were studied. The stress corrosion cracking(SCC) sensitivity was evaluated with parameters such as Kσ and Kδ.Tensile tests were divided into two groups: one was performed on tensile specimens without pre-corrosion, the other was performed on tensile specimens which were pre-corroded in 3.5%NaCl+1%H2O2 solution at 25 ℃.The results show that SCC resistance of alloy 2519 ranks in the order of T8>T7>T6 and the mechanical properties rank in the order of T6>T8>T7. SEM fractographs of the failed specimen show that the SCC sensitivity can be determined by the distribution of the second phase particles and size and the shape of grains in the alloy.

  9. Radiation Damages in Aluminum Alloy SAV-1 under Neutron Irradiation

    Science.gov (United States)

    Salikhbaev, Umar; Akhmedzhanov, Farkhad; Alikulov, Sherali; Baytelesov, Sapar; Boltabaev, Azizbek

    2016-05-01

    The aim of this work was to study the effect of neutron irradiation on the kinetics of radiation damages in the SAV-1 alloy, which belongs to the group of aluminum alloys of the ternary system Al-Mg-Si. For fast-neutron irradiation by different doses up to fluence 1019 cm-2 the SAV-1 samples were placed in one of the vertical channels of the research WWR type reactor (Tashkent). The temperature dependence of the electrical resistance of the alloy samples was investigated in the range 290 - 490 K by the four-compensation method with an error about 0.1%. The experimental results were shown that at all the temperatures the dependence of the SAV-1 alloy resistivity on neutron fluence was nonlinear. With increasing neutron fluence the deviation from linearity and the growth rate of resistivity with temperature becomes more appreciable. The observed dependences are explained by means of martensitic transformations and the radiation damages in the studied alloy under neutron irradiation. The mechanisms of radiation modification of the SAV-1 alloy structure are discussed.

  10. From 2007 to 2010,China Will Manufacture More Than 10,000 Aluminum Alloy Railcars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>The clear advantage of the aluminum alloy rail- cars is the weight reduction.The deadweight of the aluminum alloy railcars usually does not exceed 8.5t each.The 52 motor train units used in the sixth nationwide railway speedup are all made of aluminum alloys except for the train units used in the line between Guangzhou and Shenzhen.It is estimated that in 2010,there are more than 10,000 railcars made of aluminum alloys,which will consume about 105kt alumi- num.

  11. The recycling of standard quality wrought aluminum alloys from low-grade contaminated scrap

    Science.gov (United States)

    Kevorkjjan, Varužan

    2010-08-01

    In recent decades an increasingly large fraction of the world’s wrought aluminum alloys supply has come from the aluminum scrap recovered from industrial waste and discarded post-consumer items. However, replacing even a minor part of primary aluminum in wrought alloys with recycled counterpart originated from lower grades of scrap (typically scrap contaminated with various non-metallic impurities) without influencing the quality of the allay is very demanding from a metallurgical point of view. This article discusses the two approaches for achieving the requested chemical composition of wrought alloys made from recycled aluminum: (i) before melting, by combining the appropriate qualities and quantities of scrap, primary aluminum, and the alloying elements and (ii) during melting, by diluting impurity content with primary aluminum to the needed level and adding, at the same time, the necessary amount of alloying elements for achieving their standard concentration in diluted melts.

  12. Crack Repair in Aerospace Aluminum Alloy Panels by Cold Spray

    Science.gov (United States)

    Cavaliere, P.; Silvello, A.

    2017-02-01

    The cold-spray process has recently been recognized as a very useful tool for repairing metallic sheets, achieving desired adhesion strengths when employing optimal combinations of material process parameters. We present herein the possibility of repairing cracks in aluminum sheets by cold spray. A 2099 aluminum alloy panel with a surface 30° V notch was repaired by cold spraying of 2198 and 7075 aluminum alloy powders. The crack behavior of V-notched sheets subjected to bending loading was studied by finite-element modeling (FEM) and mechanical experiments. The simulations and mechanical results showed good agreement, revealing a remarkable K factor reduction, and a consequent reduction in crack nucleation and growth velocity. The results enable prediction of the failure initiation locus in the case of repaired panels subjected to bending loading and deformation. The stress concentration was quantified to show how the residual stress field and failure are affected by the mechanical properties of the sprayed materials and by the geometrical and mechanical properties of the interface. It was demonstrated that the crack resistance increases more than sevenfold in the case of repair using AA2198 and that cold-spray repair can contribute to increased global fatigue life of cracked structures.

  13. The Effect of Impurities on the Processing of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zi-Kui Liu; Shengjun Zhang; Qingyou Han; Vinod Sikka

    2007-04-23

    For this Aluminum Industry of the Future (IOF) project, the effect of impurities on the processing of aluminum alloys was systematically investigated. The work was carried out as a collaborative effort between the Pennsylvania State University and Oak Ridge National Laboratory. Industrial support was provided by ALCOA and ThermoCalc, Inc. The achievements described below were made. A method that combines first-principles calculation and calculation of phase diagrams (CALPHAD) was used to develop the multicomponent database Al-Ca-K-Li-Mg-Na. This method was extensively used in this project for the development of a thermodynamic database. The first-principles approach provided some thermodynamic property data that are not available in the open literature. These calculated results were used in the thermodynamic modeling as experimental data. Some of the thermodynamic property data are difficult, if not impossible, to measure. The method developed and used in this project allows the estimation of these data for thermodynamic database development. The multicomponent database Al-Ca-K-Li-Mg-Na was developed. Elements such as Ca, Li, Na, and K are impurities that strongly affect the formability and corrosion behavior of aluminum alloys. However, these impurity elements are not included in the commercial aluminum alloy database. The process of thermodynamic modeling began from Al-Na, Ca-Li, Li-Na, K-Na, and Li-K sub-binary systems. Then ternary and higher systems were extrapolated because of the lack of experimental information. Databases for five binary alloy systems and two ternary systems were developed. Along with other existing binary and ternary databases, the full database of the multicomponent Al-Ca-K-Li-Mg-Na system was completed in this project. The methodology in integrating with commercial or other aluminum alloy databases can be developed. The mechanism of sodium-induced high-temperature embrittlement (HTE) of Al-Mg is now understood. Using the thermodynamic

  14. The Effect of Impurities on the Processing of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zi-Kui Liu; Shengjun Zhang; Qingyou Han; Vinod Sikka

    2007-04-23

    For this Aluminum Industry of the Future (IOF) project, the effect of impurities on the processing of aluminum alloys was systematically investigated. The work was carried out as a collaborative effort between the Pennsylvania State University and Oak Ridge National Laboratory. Industrial support was provided by ALCOA and ThermoCalc, Inc. The achievements described below were made. A method that combines first-principles calculation and calculation of phase diagrams (CALPHAD) was used to develop the multicomponent database Al-Ca-K-Li-Mg-Na. This method was extensively used in this project for the development of a thermodynamic database. The first-principles approach provided some thermodynamic property data that are not available in the open literature. These calculated results were used in the thermodynamic modeling as experimental data. Some of the thermodynamic property data are difficult, if not impossible, to measure. The method developed and used in this project allows the estimation of these data for thermodynamic database development. The multicomponent database Al-Ca-K-Li-Mg-Na was developed. Elements such as Ca, Li, Na, and K are impurities that strongly affect the formability and corrosion behavior of aluminum alloys. However, these impurity elements are not included in the commercial aluminum alloy database. The process of thermodynamic modeling began from Al-Na, Ca-Li, Li-Na, K-Na, and Li-K sub-binary systems. Then ternary and higher systems were extrapolated because of the lack of experimental information. Databases for five binary alloy systems and two ternary systems were developed. Along with other existing binary and ternary databases, the full database of the multicomponent Al-Ca-K-Li-Mg-Na system was completed in this project. The methodology in integrating with commercial or other aluminum alloy databases can be developed. The mechanism of sodium-induced high-temperature embrittlement (HTE) of Al-Mg is now understood. Using the thermodynamic

  15. Textures, microstructures, anisotropy and formability of aluminum-manganese-magnesium and aluminum-magnesium alloys

    Science.gov (United States)

    Liu, Jiantao

    In this dissertation work, the microstructure and texture evolution of continuous cast (CC) and direct chill (DC) cast Al-Mn-Mg (AA 3105 and AA 3015) and Al-Mg (AA 5052) alloys during cold rolling and annealing are systematically investigated. Macrotexture analyses were based on three-dimensional orientation distribution functions (ODFs) calculated from incomplete pole figures from X-ray diffraction by using arbitrarily defined cell (ADC) and series expansion methods. A new technique, electron backscatter diffraction (EBSD), was adopted for microtexture and mesotexture investigation. The anisotropy and formability of Al-Mn-Mg and Al-Mg alloys are correlated to the texture results. For aluminum alloys studied in this work, a stronger Cube orientation is observed in DC hot band than in CC hot band after complete recrystallization. alpha and beta fibers become well developed beyond 50% cold rolling in both CC and DC aluminum alloys. The highest intensity along the beta fiber (skeleton line) is located between the Copper and the S orientations in both materials after high cold rolling reductions. In both CC and DC aluminum alloys, a cell structure develops with the indication of increasing CSL Sigma1 boundaries during the early stages of cold rolling. There is no evidence of the development of twin boundaries (Sigma3, Sigma9, Sigma27a & 27b) in either CC or DC aluminum alloys when the cold rolling reductions are less than 40%. The R and Cube textures are dominant recrystallization texture components in CC and DC AA 5052 alloys. The volume fraction of the Cube component is increased by increasing cold rolling reduction and annealing temperature but not by increasing annealing time while the volume fraction of the R component is only increased by increasing cold rolling reduction. Stronger Cube and R orientations are found at the surface layer than at half-thickness layer of cold rolled hot bands after annealing. The Cube and P textures are dominant recrystallization

  16. Structure and Hardness of 01570 Aluminum Alloy Friction Stir Welds Processed Under Different Conditions

    Science.gov (United States)

    Il'yasov, R. R.; Avtokratova, E. V.; Markushev, M. V.; Predko, P. Yu.; Konkevich, V. Yu.

    2015-10-01

    Structure and hardness of the 01570 aluminum alloy joints processed by friction stir welding at various speeds are investigated. It is shown that increasing the traverse tool speed lowers the probability of macrodefect formation in the nugget zone; however, this can lead to anomalous grain growth in the zone of contact with the tool shoulder. Typical "onion-like" structure of the weld consisting of rings that differ by optical contrast is formed for all examined welding regimes. It is demonstrated that this contrast is caused by the difference in the grain sizes in the rings rather than by their chemical or phase composition. Mechanisms of transformation of the alloy structure during friction stir welding are discussed.

  17. Electrodeposition of aluminum and aluminum-magnesium alloys at room temperature

    Institute of Scientific and Technical Information of China (English)

    阚洪敏; 祝跚珊; 张宁; 王晓阳

    2015-01-01

    Electrodeposition of aluminum from benzene-tetrahydrofuran−AlCl3−LiAlH4 was studied at room temperature. Galvanostatic electrolysis was used to investigate the effect of various parameters on deposit morphology and crystal size, including current density, temperature, molar ratio of benzene/tetrahydrofuran and stirring speed. The deposit microstructure was adjusted by changing the parameters, and the optimum operating conditions were determined. Dense, bright and adherent aluminum coatings were obtained over a wide range of current densities (10−25 mA/cm2), molar ratio of benzene and tetrahydrofuran (4:1 to 7:8) and stirring speeds (200−500 r/min). Smaller grain sizes and well-adhered deposits were obtained at lower temperatures. Aluminum-magnesium alloys could potentially be used as hydrogen storage materials. A novel method for Al−Mg deposition was proposed by using pure Mg anodes in the organic solvents system benzene-tetrahydrofuran−AlCl3−LiAlH4. XRD shows that the aluminum−magnesium alloys are mainly Al3Mg2 and Al12Mg17.

  18. Nickel-coated Steel Stud to Aluminum Alloy Joints Made by High Frequency Induction Brazing

    Institute of Scientific and Technical Information of China (English)

    GE Jiaqi; WANG Kehong; ZHANG Deku; WANG Jian

    2015-01-01

    Nickel-coated 45 steel studs and 6061 aluminum alloy with 4047 Al alloy foil asfi ller metal were joined by using high frequency induction brazing. The microstructure of Fe/Al brazed joint was studied by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). Results showed that 45 steel stud and 6061 aluminum alloy could be successfully joined by high frequency induction brazing with proper processing parameters. The bonding strength of the joint was of the order of 88 MPa. Ni coating on steel stud successfully avoided the generation of Fe-Al intermetallic compound which is brittle by blocking the contact between Al and Fe. Intermetallic compounds, i e,Al3Ni2, Al1.1Ni0.9 and Al0.3Fe3Si0.7 presented in Al side, FeNi and Fe-Al-Ni ternary eutectic structure were formed in Fe side. The micro-hardness in intermetallic compound layer was 313 HV. The joint was brittle fractured in the intermetallic compounds layer of Al side, where plenty of Al3Ni2 intermetallic compounds were distributed continuously.

  19. Sensors Array Technique for Monitoring Aluminum Alloy Spot Welding

    Institute of Scientific and Technical Information of China (English)

    王蕤; 罗震; 单平; 步贤政; 袁书现; 敖三三

    2010-01-01

    In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with ...

  20. Effects of Machining on the Microstructure of Aluminum Alloy 7075

    Science.gov (United States)

    Tabei, A.; Liang, S. Y.; Garmestani, H.

    Experimental investigations show that depending on the parameters, aggressive machining of aluminum alloy 7075 can trigger several microstructural phenomena including recrystallization, grain growth and crystallographic texture modifications below the machined surface. Increasing the depth of cut will lead to a significant recrystallization and consequently grain refinement. On the other hand, increasing the feed rate will result into development of a unique crystallographic texture. The mechanical and thermal loads imposed to the material experiences by machining leads to such microstructural phenomena. Finite element analysis is used to determine these loads.

  1. Parameter prediction in laser bending of aluminum alloy sheet

    Institute of Scientific and Technical Information of China (English)

    Xuyue WANG; Weixing XU; Hua CHEN; Jinsong WANG

    2008-01-01

    Based on the basic platform of BP neural net-works, a BP network model is established to predict the bending angle in the laser bending process of an aluminum alloy sheet (1-2 mm in thickness) and to optimize laser bending parameters for bending control. The sample experimental data is used to train the BP network. The nonlinear regularities of sample data are fitted through the trained BP network; the predicted results include laser bending angles and parameters. Experimental results indi-cate that the prediction allowance is controlled less than 5%-8% and can provide a theoretical and experimental basis for industry purpose.

  2. Solar selective black nickel-cobalt coatings on aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shashikala, A.R.; Sharma, A.K.; Bhandari, D.R. [Thermal System Group, ISRO Satellite Centre, Bangalore 560 017 (India)

    2007-04-16

    Solar selective black nickel-cobalt plating on pre cleaned aluminum alloy substrates with nickel undercoat were investigated. Process optimization was carried out by the hull cell experiments investigating the influence of operating variables on the optical selectivity of the coating. The coatings were characterized with scanning electron microscope, X-ray diffraction, energy dispersive X-ray spectroscopic and polarization studies. Evaluation of the coatings was carried out by adhesion, measurement of coating thickness and optical properties, humidity, thermal cycling, thermo-vacuum performance and thermal stability tests. (author)

  3. Corrosion damage evolution and residual strength of corroded aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Youhong Zhang; Guozhi Lv; Hui Wang; Bomei Si; Yueliang Cheng

    2008-01-01

    The LY12CZ aluminum alloy specimens were eurroded under the conditions of different test temperatures and exposure durations. After corrosion exposure, fatigue tests were performed. Scanning electron microscopy and optical microscope analyses on corrosion damage were carried out. The definition of surface corrosion damage ratio was provided to describe the extent of surface corrosion damage. On the basis of the measured data sets of the corrosion damage ratio, the probabilistic model of corrosion damage evolution was built. The corrosion damage decreased the fatigue life by a factor of about 1.25 to 2.38 and the prediction method of residual strength of the corroded structure was presented.

  4. Recrystallization model for hot-rolling of 5182 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A recrystallization model for hot-rolling of 5182 aluminum alloy was presented by means of the fractional softening during double interval deformation. It is found that the recrystallization rate depends on strain rate more sensitively than deformation temperature, and the time for full recrystallization is very short as strain rate is greater than 1 s-1. Using the recrystallization—time—temperature curves, the desirable hot rolled microstructure can be obtained by controlling the rolling speed, temperature and cooling rate before cooling during the last pass in reversing mill.

  5. Characterization of Nanocrystalline Aluminum Alloy 5083 Powders Produced by Cryogenic Attrition

    Science.gov (United States)

    2014-11-01

    Characterization of Nanocrystalline Aluminum Alloy 5083 Powders Produced by Cryogenic Attrition by Tiffany Ngo ARL-TN-0643...November 2014 Characterization of Nanocrystalline Aluminum Alloy 5083 Powders Produced by Cryogenic Attrition Tiffany Ngo Weapons and... Materials Research Directorate, ARL Approved for public release; distribution is unlimited

  6. A Rare Earth High-iron Aluminum Alloy Cable Company to Settle in Chongqing

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On September 14,the reporter learnt from the Seminar on Application of New Rare Earth High-iron Aluminum Alloy Cable Technologies for Energy Conservation and Environmental Protection held by Chongqing Electric Industry Association that a rare earth high-iron aluminum alloy cable company with

  7. Corrosive wear behavior of 2014 and 6061 aluminum alloy composites

    Energy Technology Data Exchange (ETDEWEB)

    Varma, S.K.; Andrews, S.; Vasquez, G. [Univ. of Texas, El Paso, TX (United States). Dept. of Metallurgical and Materials Engineering

    1999-02-01

    Alloys of 2014 and 6061 aluminum reinforced with 0.1 volume fraction of alumina particles (VFAP) were subjected to impact scratching during a corrosive wear process. The transient currents generated due to the impact were measured in the two composites as well as in their respective monoliths. The effect of solutionizing time on the transient currents was correlated to the near surface microstructures, scratch morphology, concentration of quenched-in vacancies, and changes in grain sizes. It was observed that the transient current values increase with an increase in solutionizing time, indicating that the corrosive wear behavior is not strongly affected by the grain boundaries. However, a combination of pitting and the galvanic corrosion may account for the typical corrosive wear behavior exhibited by the alloys and the composites of this study.

  8. Rheo-diecasting Process for Semi-solid Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel one-step semisolid processing technique, the rheo-diecasting (RDC) process, was developed, which adapts in situ creation of semisolid metal slurry with fine and spherical solid particles followed by direct shaping of the slurry into a near-net shape component using the existing cold chamber diecasting process. The RDC process was applied to process A356 and A380 aluminum alloys. The resulting microstructures and mechanical properties of RDC products under as-cast and various heat treatment conditions were analyzed. The experimental results show that the RDC samples have an extremely low porosity, a fine and uniform microstructure throughout entire casting, and consequently much improved strength and ductility in the as-cast condition. The strength of RDC A356 alloy can be substantially improved under T5 and T6 heat treatments without loss of ductility.

  9. Damage percolation during stretch flange forming of aluminum alloy sheet

    Science.gov (United States)

    Chen, Zengtao; Worswick, Michael J.; Keith Pilkey, A.; Lloyd, David J.

    2005-12-01

    A multi-scale finite element (FE)-damage percolation model was employed to simulate stretch flange forming of aluminum alloys AA5182 and AA5754. Material softening and strain gradients were captured using a Gurson-based FE model. FE results were then fed into the so-called damage percolation code, from which the damage development was modelled within measured microstructures. The formability of the stretch flange samples was predicted based upon the onset of catastrophic failure triggered by profuse void coalescence within the measured second-phase particle field. Damage development is quantified in terms of crack and void areal fractions, and compared to metallographic results obtained from interrupted stretch flange specimens. Parametric study is conducted on the effect of void nucleation strain in the prediction of formability of stretch flanges to "calibrate" proper nucleation strains for both alloys.

  10. Material and information flows pertaining to aluminum alloy pipe distribution

    Directory of Open Access Journals (Sweden)

    D. Simić

    2013-10-01

    Full Text Available This paper discusses the distribution flow of aluminum (Al alloy pipes, starting with the completion of the manufacturing process and final inspection. The proposed solution considers the use of bar-coded caps produced from recycled polymer materials that are placed on the ends of the tubes in order to achieve protection against potential changes in material properties and preserve the product quality. For the preparation of capped tube bundles for shipment from the manufacturer output storage to the customer input warehouse, a technical solution that enables correct and efficient Al alloy pipe handling is proposed, in terms of safety, security, reliability, financial feasibility and ecological viability, with optimal utilization of transport and storage.

  11. Use of Permanent Magnets in Electromagnetic Facilities for the Treatment of Aluminum Alloys

    Science.gov (United States)

    Beinerts, Toms; Bojarevičs, Andris; Bucenieks, Imants; Gelfgat, Yuri; Kaldre, Imants

    2016-06-01

    The possibility of applying the electromagnetic induction pump with permanent magnets for the transportation and stirring of aluminum melts in metallurgical furnaces is investigated. The electromagnetic and hydraulic characteristics of the pump have been investigated theoretically and experimentally with regard to its position in the furnace. The results of the experiments performed with a model in a eutectic InGaSn melt are in good agreement with the calculation data. Extrapolation of the experimental results on the physical characteristics of aluminum melts allows recommending such pumps for contactless control of motion and heat/mass transfer in aluminum melts in different technological processes. A high temperature and the aggressive properties of aluminum alloys make it complicated to use different mechanical devices to solve technological problems, such as liquid metal transportation, dosing, stirring, etc. In this case, any device units or elements moving in or contacting with the melt suffer from corrosion polluting the melt. Therefore, of more importance and topicality are contactless electromagnetic methods for processing of molten metals.

  12. Air cushion furnace technology for heat treatment of high quality aluminum alloy auto body sheet

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Zhaodong; Ma Mingtu; Wang Guodong; Fu Tianliang; Li Jiadong; Liang Xiong

    2014-01-01

    The process characteristics of heat treatment of aluminum alloy auto body sheet and the working prin-ciple of air cushion furnace were introduced. The process position and irreplaceable role of air cushion furnace in the aluminum alloy auto body sheet production was pointed out after the difficulty and key points in the whole production process of auto body sheet were studied. Then the development process of air cushion furnace line of aluminum alloy sheet was reviewed,summarized and divided to two stages. Based on the research of air cushion furnace,the key technology of it was analyzed,then the key points on process,equipment and control models of air cushion furnace for aluminum alloy auto body sheet in future were put forward. With the rapid de-velopment of automotive industry,there will be certainly a new upsurge of research and application of air cush-ion furnace for heat treatment of aluminum alloy auto body sheet.

  13. Stress Relaxation Behavior and Springback Equation of 7050 Aluminum Alloys During Age-forming Process

    Directory of Open Access Journals (Sweden)

    REN Wei-wei

    2016-09-01

    Full Text Available The stress relaxation behavior and springback equation of 7050 aluminum alloys during the age-forming process were studied through self-designed uniaxial tension device. The results show that in traditional aging temperature, the stress relaxation curve of 7050 aluminum alloys exhibits a classical logarithmic decrement curve. The stress relaxation process can be divided into three stages, which are the initial stress decayed fast stage, the subsequent stress slowly decayed stage and the stress constantly maintained stage, respectively. Stress relaxation limit of 7050 aluminum alloys decreases with increasing aging temperature. The threshold stress presents during the stress relaxation process due to the interaction between precipitation behavior and dislocation creep of 7050 aluminum alloys. The stress relaxation equation of 7050 aluminum alloys is obtained through resolving the feature and Taylor equation of relaxation process, and using the stress relaxation equation can precisely predict the springback of workpiece after age-forming.

  14. A perspective of microplasma oxidation (MPO) and vapor deposition coatings in surface engineering of aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    AWAD Samir Hamid; QIAN Han-cheng

    2004-01-01

    Over the past years, great achievements have been made in the development of coating technologies for surface improvement of aluminum alloys. Despite these achievements, the role in the market strongly depends on the ability of surface coating technology under technical and economic considerations to meet the increased demands for heavy tribological applications of aluminum alloys. Microplasma oxidation (MPO) technology has recently been studied as a novel and effective means to provide thick and hard ceramic coating with improved properties such as excellent load-bearing and wear resistance properties on aluminum alloys. The present work covers the evaluation of the performances of current single and duplex coatings combining MPO, physical vapor deposition (PVD), and plasma assisted chemical vapor deposition (PACVD) coatings on aluminum alloys. It suggests that the MPO coating is a promising candidate for design engineers to apply aluminum alloys to heavy load-bearing applications. The prospective future for the research on MPO coatings is introduced as well.

  15. Single-aging characteristics of 7055 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; YIN Zhi-min; SHEN Kai; LI Jie; HUANG ji-wu

    2007-01-01

    The microstructures and properties of 7055 aluminum alloy were studied at different single-aging for up to 48 h using hardness test, tensile test, electrical conductivity measurement, XRD and TEM microstructure analysis. The results show that at the early stage of aging, the hardness and strength of the alloy increase rapidly, the peak hardness and strength are approached after 120 ℃ aging for 4 h, then maintained at a high level for a long time. The suitable single-aging treatment of 7055 alloy is 480 ℃, 1 h solution treatment and water quenching, then aging at 120 ℃ for 24 h. Under those condition, the tensile strength, yield strength, elongation and electrical conductivity of the studied alloy are 513 MPa, 462 MPa, 9.5% and 29%(IACS), respectively. During aging, the solid solution decomposes and precipitation occurs. At the early aging stage of 120 ℃, GP zones form and then grow up gradually with increasing ageing time. η' phase forms after ageing for 4 h and η phase starts to occur after 24 h aging.

  16. Helical Feed Milling with MQL for Boring of Aluminum Alloy

    Science.gov (United States)

    Sasahara, Hiroyuki; Kawasaki, Makoto; Tsutsumi, Masaomi

    MQL is applied to the helical feed milling hole-making process of aluminum alloy. It is difficult to drill on aluminum alloy without cutting fluid because the adhesion to the tool leads to a chip jam, the tool breakage or low accuracy. By employing the helical feed milling, cutting temperature will decrease, each chip length will become short and a chip jam in a hole will be avoided, because the intermittent cutting is realized. As a result of employing the helical feed milling with MQL, it was shown that the shape error is decreased, a burr formation is decreased, machining temperature becomes low and the cutting force becomes small comparing with drilling process. Shape error by helical feed milling with MQL is comparable with that with flood coolant. In this case, small mist particle counts under 5μm, which affects working environment, are almost constant if the spindle speed varies. Scattered mist particle counts are less when MQL is employed over 20000 min-1 spindle speed comparing with the flood coolant.

  17. Laser shocking of 2024 and 7075 aluminum alloys

    Science.gov (United States)

    Clauer, A. H.; Fairand, B. P.; Slater, J. E.

    1977-01-01

    The effect of laser generated stress waves on the microstructure, hardness, strength and stress corrosion resistance of 2024 and 7075 aluminum alloys was investigated. Pulsed CO2 and neodymium-glass lasers were used to determine the effect of wavelength and pulse duration on pressure generation and material property changes. No changes in material properties were observed with CO2 laser. The strength and hardness of 2024-T351 and the strength of 7075-T73 aluminum alloys were substantially improved by the stress wave environments generated with the neodymium-glass laser. The mechanical properties of 2024-T851 and 7075-T651 were unchanged by the laser treatment. The correlation of the laser shock data with published results of flyer plate experiments demonstrated that a threshold pressure needed to be exceeded before strengthening and hardening could occur. Peak pressures generated by the pulsed laser source were less than 7.0 GPa which was below the threshold pressure required to change the mechanical properties of 2024-T851 and 7075-T651. Corrosion studies indicated that laser shocking increased the resistance to local attack in 2024-T351 and 7075-T651.

  18. Fatigue crack growth in an aluminum alloy-fractographic study

    Science.gov (United States)

    Salam, I.; Muhammad, W.; Ejaz, N.

    2016-08-01

    A two-fold approach was adopted to understand the fatigue crack growth process in an Aluminum alloy; fatigue crack growth test of samples and analysis of fractured surfaces. Fatigue crack growth tests were conducted on middle tension M(T) samples prepared from an Aluminum alloy cylinder. The tests were conducted under constant amplitude loading at R ratio 0.1. The stress applied was from 20,30 and 40 per cent of the yield stress of the material. The fatigue crack growth data was recorded. After fatigue testing, the samples were subjected to detailed scanning electron microscopic (SEM) analysis. The resulting fracture surfaces were subjected to qualitative and quantitative fractographic examinations. Quantitative fracture analysis included an estimation of crack growth rate (CGR) in different regions. The effect of the microstructural features on fatigue crack growth was examined. It was observed that in stage II (crack growth region), the failure mode changes from intergranular to transgranular as the stress level increases. In the region of intergranular failure the localized brittle failure was observed and fatigue striations are difficult to reveal. However, in the region of transgranular failure the crack path is independent of the microstructural features. In this region, localized ductile failure mode was observed and well defined fatigue striations were present in the wake of fatigue crack. The effect of interaction of growing fatigue crack with microstructural features was not substantial. The final fracture (stage III) was ductile in all the cases.

  19. Flexural-torsional buckling behavior of aluminum alloy beams

    Institute of Scientific and Technical Information of China (English)

    Xiaonong GUO; Zhe XIONG; Zuyan SHEN

    2015-01-01

    This paper presents an investigation on the flexural-torsional buckling behavior of aluminum alloy beams (AAB). First, based on the tests of 14 aluminum alloy beams under concentrated loads, the failure pattern, load- deformation curves, bearing capacity and flexural-torsional buckling factor are studied. It is found that all the beam specimens collapsed in the flexuml-torsional buckling with excessive deformation pattern. Moreover, the span, loading location and slenderness ratio influence the flexural-torsional buckling capacity of beams significantly. Secondly, besides the experiments, a finite element method (FEM) analysis on the flexural-torsional buckling behavior of AAB is also conducted. The main parameters in the FEM analysis are initial imperfection, material property, cross-section and loading scheme. According to the analytical results, it is indicated that the FEM is reasonable to capture mechanical behavior of AAB. Finally, on the basis of the experimental and analytical results, theoretical formulae to estimate the flexural- torsional buckling capacity of AAB are proposed, which could improve the application of present codes for AAB.

  20. Defect analysis of complex-shape aluminum alloy forging

    Institute of Scientific and Technical Information of China (English)

    SHAN De-bin; ZHANG Yan-qiu; WANG Yong; XU Fu-chang; XU Wen-chen; L(U) Yan

    2006-01-01

    The isothermal precision forging was applied for the purpose of forming aluminum alloy with complex shape. The complexity of forging is easy to lead to the occurrence of the defects, such as underfilling, folding, metal flow lines disturbance and fibre breaking. The reasons for the defects were analyzed on the basis of experiments and finite element method(FEM). The results show that the size of flash gutter bridge, the lubricating condition and the deformation process are the main factors influencing the filling qualities of complex-shape aluminum alloy forging. The folding defect is mainly caused by different velocities of filling cavities, fast flow of much metal in one direction and confluence of two or multi metal strands. Improper metal distribution in different regions can cause the flow lines disturbance and fast metal flow in one direction is also a cause of the flow lines disturbance According to the reasons, some measures were taken to improve the quality of the forged parts. These studies can contribute to offering some experiences in making process project and optimizing the process parameters for forging complex-shape aviation products.

  1. Conversion Coatings for Aluminum Alloys by Chemical Vapor Deposition Mechanisms

    Science.gov (United States)

    Reye, John T.; McFadden, Lisa S.; Gatica, Jorge E.; Morales, Wilfredo

    2004-01-01

    With the rise of environmental awareness and the renewed importance of environmentally friendly processes, the United States Environmental Protection Agency has targeted surface pre-treatment processes based on chromates. Indeed, this process has been subject to regulations under the Clean Water Act as well as other environmental initiatives, and there is today a marked movement to phase the process out in the near future. Therefore, there is a clear need for new advances in coating technology that could provide practical options for replacing present industrial practices. Depending on the final application, such coatings might be required to be resistant to corrosion, act as chemically resistant coatings, or both. This research examined a chemical vapor deposition (CVD) mechanism to deposit uniform conversion coatings onto aluminum alloy substrates. Robust protocols based on solutions of aryl phosphate ester and multi-oxide conversion coating (submicron) films were successfully grown onto the aluminum alloy samples. These films were characterized by X-ray Photoelectron Spectroscopy (XPS). Preliminary results indicate the potential of this technology to replace aqueous-based chromate processes.

  2. Assessment Of Usability Of Molten Salt Mixtures In Metallurgy Of Aluminum Alloys And Recycling Of Composite Materials Based On The Matrix Of Al Alloys

    Directory of Open Access Journals (Sweden)

    Jackowski J.

    2015-09-01

    Full Text Available Effectiveness of the slags used in metallurgy of aluminum alloys and in recycling of composite materials containing these alloys depends on their surface properties at the phase boundaries they are in contact with. An index of surface properties of molten mixtures of slag-forming salts has been formulated. Its calculated values are compared with measured results of surface tension (liquid – atmosphere and interfacial tension (liquid – liquid in the considered systems. It was found that the index can be helpful for purposes of proper choice of the mixtures of slag-forming salts used both in Al alloys metallurgy and in recycling of composite materials based on the matrix of Al alloys.

  3. Fatigue Resistance of Liquid-assisted Self-repairing Aluminum Alloys Reinforced with Shape Memory Alloys

    Science.gov (United States)

    Wright, M. Clara; Manuel, Michele; Wallace, Terryl

    2013-01-01

    A self-repairing aluminum-based composite system has been developed using a liquid-assisted healing theory in conjunction with the shape memory effect of wire reinforcements. The metal-metal composite was thermodynamically designed to have a matrix with a relatively even dispersion of a low-melting eutectic phase, allowing for repair of cracks at a predetermined temperature. Additionally, shape memory alloy (SMA) wire reinforcements were used within the composite to provide crack closure. Investigators focused the research on fatigue cracks propagating through the matrix in order to show a proof-of-concept Shape Memory Alloy Self-Healing (SMASH) technology for aeronautical applications.

  4. Thermal Decoating of Aerospace Aluminum Alloys for Aircraft Recycling

    Science.gov (United States)

    Muñiz Lerma, Jose Alberto; Jung, In-Ho; Brochu, Mathieu

    2016-06-01

    Recycling of aircraft aluminum alloys can be complex due to the presence of their corrosion protection coating that includes inorganic compounds containing Cr(VI). In this study, the characterization and thermal degradation behavior of the coating on aluminum substrates coming from an aircraft destined for recycling are presented. Elements such as Sr, Cr, Si, Ba, Ti, S, C, and O were found in three different layers by EDS elemental mapping corresponding to SrCrO4, Rutile-TiO2, SiO2, and BaSO4 with an overall particle size D 50 = 1.96 µm. The thermal degradation profile analyzed by TGA showed four different stages. The temperature of complete degradation at the fourth stage occurred at 753.15 K (480 °C) at lower heating rates. At higher heating rates and holding an isotherm at the same temperature, the residence time to fully decompose the aircraft coating has been estimated as 4.0 ± 0.2 minutes. The activation energy calculated by the Flynn-Wall-Ozawa and the modified Coats-Redfern methods for multiple fraction of decomposition showed a non-constant behavior indicating the complexity of the reaction. Finally, the concentration of Cr(VI) released to the environment during thermal decoating was obtained by UV-Vis spectroscopy. It was found that 2.6 ± 0.1 µg of Cr(VI)/mm2 of aluminum substrate could be released unless adequate particle controls are used.

  5. Wettability of Molten Aluminum-Silicon Alloys on Graphite and Surface Tension of Those Alloys at 1273 K (1000 °C)

    Science.gov (United States)

    Mao, Weiji; Noji, Takayasu; Teshima, Kenichiro; Shinozaki, Nobuya

    2016-06-01

    The wettability of molten aluminum-silicon alloys with silicon contents of 0, 6, 10, and 20 mass pct on graphite substrates by changing the placing sequence of aluminum and silicon and the surface tension of those alloys were investigated at 1273 K (1000 °C) using the sessile drop method under vacuum. The results showed that the wetting was not affected by changing the placing sequence of the Al-Si alloys on the graphite substrates. The wettability was not improved significantly upon increasing the Si content from 0 to 10 mass pct, whereas a notable decrease of 22 deg in the contact angle was observed when increasing the Si content from 10 to 20 mass pct. This was attributed to the transformation of the interfacial reaction product from Al4C3 into SiC, provided the addition of Si to Al was sufficient. It was verified that the liquid Al can wet the SiC substrate very well in nature, which might explain why the occurrence of SiC would improve the wettability of the Al-20 mass pct Si alloy on the graphite substrate. The results also showed that the surface tension values of the molten Al-Si alloys decreased monotonously with an increase in Si content, being 875, 801, 770, and 744 mN/m for molten Al, Al-6 mass pct Si, Al-10 mass pct Si, and Al-20 mass pct Si alloys, respectively.

  6. Synthesis of metastable aluminum-based intermetallics by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, R.B.; Srinivasan, S.; Desch, P.B.

    1991-01-01

    We have used mechanical alloying (MA) to prepare fine-grained powders of Al 25 at. % X (X = Ti, Zr, Hf) having the metastable cubic L1{sub 2} structure. Hexane (C{sub 6}H{sub 14}) is added to the milling media to avoid the agglomeration of the aluminum powder. Carbon from the decomposition of the hexane incorporates into the powder to form a fine dispersion of carbides. These carbides are beneficial because they limit grain growth during consolidation and add strength to the alloy. We have consolidated the mechanically alloyed powders using conventional hot-pressing and non-conventional dynamic pressing. We used hot pressing to consolidate mechanically alloyed L1{sub 2}-Al{sub 3}Ti powder in the presence of excess of Al. The compact has the DO{sub 22} structure. Its room-temperature compressive strength is 1.2 GPa (exceeding that of cast Al{sub 3}Ti by a factor of 10). At 400{degrees}C, the compressive strength decreases to 1 GPa. The ductility, which is negligible at room temperature, increases to 6% at 400{degrees}C. We used dynamic pressing to consolidate L1{sub 2}-Al{sub 5}CuZr{sub 2} powder. The compact, having the L1{sub 2} structure, has fine grains (44 nm) and a fine dispersion of ZrC precipitates (7 nm). Its hardness is in the range of 1030 kg mm{sup {minus}2}. Current efforts are to investigate ternary alloys based on fine-grained trialuminides which include a ductile second phase. 26 refs., 8 figs.

  7. Friction stir welding characteristics of two aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    刘会杰; 藤井英俊; 前田将克; 野城清

    2003-01-01

    The friction stir welding characteristics of the strain-hardened AA1050-H24 and precipitate-hardened AA2017-T351 aluminum alloys were examined in order to reveal the effects of the alloy properties on the friction stir welding behavior of the base materials. The results show that (1) for AA1050-H24, the weld possesses a smooth surface and clear ripples, there is no elliptical weld nugget in the weld, there is not discernible interface between the stir zone and the thermo-mechanically affected zone(TMAZ), and the internal defect of the weld looks like a long crack and is located in the lower part of the weld; (2) for AA2017-T351, the weld usually possesses a rough surface and visible ripples, the elliptical weld nugget clearly exists in the weld and there is obvious plastic flow and a discernible interface between the nugget and the TMAZ, and the internal defect of the weld is composed of many voids and distributed in the middle part of the weld; (3) the effective ranges of the welding parameters for AA1050-H24 and AA2017-T351 are both narrow, especially for the latter; and (4) the tensile strength efficiencies of the joints for the two typical alloys are similar, i e 79% for AA1050-H24 and 82% for AA2017-T351.

  8. Modeling the Controlled Recrystallization of Particle-Containing Aluminum Alloys

    Science.gov (United States)

    Adam, Khaled; Root, Jameson M.; Long, Zhengdong; Field, David P.

    2016-12-01

    The recrystallized fraction for AA7050 during the solution heat treatment is highly dependent upon the history of deformation during thermomechanical processing. In this work, a state variable model was developed to predict the recrystallization volume fraction as a function of processing parameters. Particle stimulated nucleation (PSN) was observed as a dominant mechanism of recrystallization in AA7050. The mesoscale Monte Carlo Potts model was used to simulate the evolved microstructure during static recrystallization with the given recrystallization fraction determined already by the state variable model for AA7050 alloy. The spatial inhomogeneity of nucleation is obtained from the measurement of the actual second-phase particle distribution in the matrix identified using backscattered electron (BSE) imaging. The state variable model showed good fit with the experimental results, and the simulated microstructures were quantitatively comparable to the experimental results for the PSN recrystallized microstructure of 7050 aluminum alloy. It was also found that the volume fraction of recrystallization did not proceed as dictated by the Avrami equation in this alloy because of the presence of the growth inhibitors.

  9. Modeling the Controlled Recrystallization of Particle-Containing Aluminum Alloys

    Science.gov (United States)

    Adam, Khaled; Root, Jameson M.; Long, Zhengdong; Field, David P.

    2017-01-01

    The recrystallized fraction for AA7050 during the solution heat treatment is highly dependent upon the history of deformation during thermomechanical processing. In this work, a state variable model was developed to predict the recrystallization volume fraction as a function of processing parameters. Particle stimulated nucleation (PSN) was observed as a dominant mechanism of recrystallization in AA7050. The mesoscale Monte Carlo Potts model was used to simulate the evolved microstructure during static recrystallization with the given recrystallization fraction determined already by the state variable model for AA7050 alloy. The spatial inhomogeneity of nucleation is obtained from the measurement of the actual second-phase particle distribution in the matrix identified using backscattered electron (BSE) imaging. The state variable model showed good fit with the experimental results, and the simulated microstructures were quantitatively comparable to the experimental results for the PSN recrystallized microstructure of 7050 aluminum alloy. It was also found that the volume fraction of recrystallization did not proceed as dictated by the Avrami equation in this alloy because of the presence of the growth inhibitors.

  10. High Strength and Wear Resistant Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    In this paper, a new high strength and wear resistant aluminum cast alloy invented by NASA-MSFC for high temperature applications will be presented. Developed to meet U.S. automotive legislation requiring low-exhaust emission, the novel NASA 398 aluminum-silicon alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (500 F-800 F), enabling new pistons to utilize less material, which can lead to reducing part weight and cost as well as improving performance. NASA 398 alloy also offers greater wear resistance, surface hardness, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys for several commercial and automotive applications. The new alloy can be produced economically using permanent steel molds from conventional gravity casting or sand casting. The technology was developed to stimulate the development of commercial aluminum casting products from NASA-developed technology by offering companies the opportunity to license this technology.

  11. Fracture characteristics of structural aerospace alloys containing deep surface flaws. [aluminum-titanium alloys

    Science.gov (United States)

    Masters, J. N.; Bixler, W. D.; Finger, R. W.

    1973-01-01

    Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions.

  12. Micromechanical models of delamination in aluminum-lithium alloys

    Science.gov (United States)

    Messner, Mark Christian

    Aluminum lithium (Al-Li) alloys are lighter, stiffer, and tougher than conventional aerospace aluminum alloys. Replacing conventional aluminums with Al-Li could substantially decrease the weight and cost of aerospace structures. However, Al-Li alloys often fracture intergranularly via a mechanism called delamination cracking. While secondary delamination cracks can improve the effective toughness of a component, no current model accurately predicts the initiation and growth of intergranular cracks. Since simulations cannot incorporate delamination into a structural model, designers cannot quantify the effect of delamination cracking on a particular component. This uncertainty limits the application of Al-Li alloys. Previous experiments identify microstructural features linked to delamination. Fractography of failed surfaces indicates plastic void growth triggers intergranular failure. Furthermore, certain types of soft/stiff grain boundaries tend to localize void growth and nucleate delamination cracks. This dissertation develops a mechanism for the initiation of delamination on the microscale that accounts for these experimental observations. Microscale simulations of grain boundaries near a long primary crack explore the delamination mechanism on the mesoscale. In these simulations, a physically-based crystal plasticity (CP) model represents the constitutive response of individual grains. This CP model incorporates plastic voriticity correction terms into a standard objective stress rate integration, to accurately account for the kinematics of lattice deformation. The CP model implements slip system hardening with a modular approach to facilitate quick testing and calibration of different theories of hardening. The microscale models reveal soft/stiff grain boundaries develop elevated mean stress and plastic strain as a consequence of the mechanics of the interface. These elevated stresses and strain drive plastic void growth. The results indicate plastic void

  13. Properties of welded joints in laser welding of aeronautic aluminum-lithium alloys

    Science.gov (United States)

    Malikov, A. G.; Orishich, A. M.

    2017-01-01

    The work presents the experimental investigation of the laser welding of the aluminum-lithium alloys (system Al-Mg-Li) and aluminum alloy (system Al-Cu-Li) doped with Sc. The influence of the nano-structuring of the surface layer welded joint by the cold plastic deformation method on the strength properties of the welded joint is determined. It is founded that, regarding the deformation degree over the thickness, the varying value of the welded joint strength is different for these aluminum alloys.

  14. Elevated temperature crack growth in advanced powder metallurgy aluminum alloys

    Science.gov (United States)

    Porr, William C., Jr.; Gangloff, Richard P.

    1990-01-01

    Rapidly solidified Al-Fe-V-Si powder metallurgy alloy FVS0812 is among the most promising of the elevated temperature aluminum alloys developed in recent years. The ultra fine grain size and high volume fraction of thermally stable dispersoids enable the alloy to maintain tensile properties at elevated temperatures. In contrast, this alloy displays complex and potentially deleterious damage tolerant and time dependent fracture behavior that varies with temperature. J-Integral fracture mechanics were used to determine fracture toughness (K sub IC) and crack growth resistance (tearing modulus, T) of extruded FVS0812 as a function of temperature. The alloy exhibits high fracture properties at room temperature when tested in the LT orientation, due to extensive delamination of prior ribbon particle boundaries perpendicular to the crack front. Delamination results in a loss of through thickness constraint along the crack front, raising the critical stress intensity necessary for precrack initiation. The fracture toughness and tensile ductility of this alloy decrease with increasing temperature, with minima observed at 200 C. This behavior results from minima in the intrinsic toughness of the material, due to dynamic strain aging, and in the extent of prior particle boundary delaminations. At 200 C FVS0812 fails at K levels that are insufficient to cause through thickness delamination. As temperature increases beyond the minimum, strain aging is reduced and delamination returns. For the TL orientation, K (sub IC) decreased and T increased slightly with increasing temperature from 25 to 316 C. Fracture in the TL orientation is governed by prior particle boundary toughness; increased strain localization at these boundaries may result in lower toughness with increasing temperature. Preliminary results demonstrate a complex effect of loading rate on K (sub IC) and T at 175 C, and indicate that the combined effects of time dependent deformation, environment, and strain aging

  15. Subsequent yield loci of 5754O aluminum alloy sheet

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-bo; WAN Min; WU Xiang-dong; YAN Yu

    2009-01-01

    Complex loading paths were realized with cruciform specimens and biaxial loading testing machine. Experimental method for determining the subsequent yield locus of sheet metal was established. With this method, the subsequent yield loci of 5754O aluminum alloy sheet were obtained under complex loading paths. Theoretical subsequent yield loci based on Yld2000-2d yield criterion and three kinds of hardening modes were calculated and compared with the experimental results. The results show that the theoretical subsequent yield loci based on mixed hardening mode describe the experimental subsequent yield loci well, whereas isotropic hardening mode, which is widely used in sheet metal forming fields, predicts values larger than the experimental results. Kinematic hardening mode predicts values smaller than the experimental results and its errors are the largest.

  16. Microstructural stability of ultrafine grained cold sprayed 6061 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rokni, M.R., E-mail: mohammadreza.rokni@mines.sdsmt.edu [Department of Materials and Metallurgical Engineering, Advanced Materials Processing Center, South Dakota School of Mines and Technology (SDSM and T), SD (United States); Widener, C.A. [Department of Materials and Metallurgical Engineering, Advanced Materials Processing Center, South Dakota School of Mines and Technology (SDSM and T), SD (United States); Champagne, V.R. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD (United States)

    2014-01-30

    The microstructural stability of ultrafine grained (UFG) cold spray 6061 aluminum deposits produced by high pressure cold spray were investigated by in situ heating to a fully annealed state via a hot-stage transmission electron microscope (TEM). It was possible to observe the precise locations and temperatures of different microstructural changes, like dislocation movement and other restoration processes. Even after heating up to the annealing temperature for this alloy, the deposited layer in the perpendicular direction was found to preserve the UFG structures, which were the result of different recrystallization mechanisms caused by the high strains present during cold spraying. Extensive solute segregation at the grain boundaries acted as an obstruction for grain boundary migration in this direction, thereby preventing grain growth. However, in the direction parallel to the deposited surface, the UFGs were not resistant to grain coursing like the other direction, since the grain boundaries had much less solute segregation.

  17. Laser vision sensing based on adaptive welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhixiang; SONG Yonglun; ZHANG Jun; ZHANG Wanchun; JIANG Li; XIA Xuxin

    2007-01-01

    A laser vision sensing based on the adaptive tungsten inert gas(TIG)welding system for large-scale aluminum alloy components was established to fit various weld groove conditions.A new type of laser vision sensor was used to precisely measure the weld groove.The joint geometry data,such as the bevel angle,the gap,the area,and the mismatch,etc.,aided in assembling large-scale aerospace components before welding.They were also applied for automatic seam tracking,such as automatic torch transverse alignment and torch height adjustment in welding.An adaptive welding process was realized by automatically adjusting the wire feeding speed and the welding current according to the groove conditions.The process results in a good weld formation and high welding quality,which meet the requirements of related standards.

  18. Mechanisms of pressure filtration of liquid aluminum alloys

    Science.gov (United States)

    Cao, X.

    2006-12-01

    The Prefil Footprinter, a portable pressure filtration instrument, is usually used to detect the quality of liquid aluminum alloys. However, no investigations have ever been done to calculate the cake resistance to date. Based on the identification and classification of flow behavior using the first derivative method for filtrate mass vs filtration time curves, conventional filtration equations are successfully employed to understand the filtration behaviors. From the analyses of the variations of cake resistance with filtration time, the filtration mechanisms are discussed in detail over the different filtration stages. During the steady stage, either incompressible or compressible cake mode is the main mechanism. At the initial and terminal transient stages, however, deep-bed filtration, complete straining, and solidification clogging may appear. Solid inclusions in liquid metal have significant influence on the cake structures and properties. Some important issues related to the heterogeneity of filter media and test methodology are highlighted in this work.

  19. Microstructure characteristics and mechanical properties of rheocasting 7075 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Yang Bin

    2013-09-01

    Full Text Available The microstructure characteristics and mechanical properties of 7075 aluminum alloy produced by a new rheoforming technique, under as-cast and optimized heat treatment conditions, were investigated. The present rheoforming combined the innovatively developed rheocasting process, named as ICSPC (inverted cone-shaped pouring channel process, and the existing HPDC (high pressure die casting process. The experimental results show that the ICSPC can be used to prepare high quality semi-solid slurry for the subsequent die casting. Compared with conventional HPDC process, the ICSPC process can improve the microstructures and mechanical properties of the cast tensile samples. An optimized heat treatment results in significant improvement in ultimate tensile strength. However, the ductility of the samples, both under as-cast and optimized heat treatment conditions, are relatively poor.

  20. Applications of pattern recognition in aluminum alloy texture characterization

    Science.gov (United States)

    Liu, Guizhong; Rehbein, D. K.; Foley, James C.; Thompson, R. B.

    2000-05-01

    This paper presents a methodology to extract texture information in Aluminum alloys using pattern recognition algorithm. The orientation of the samples can be obtained by the orientation Image Microscope (OIM) technique. The ISO DATA pattern recognition algorithm is implemented to classify the OIM data into different clusters. Based on the classification results, the probability density function (pdf) is estimated. Then, the pdf is expanded as a series of Legendre functions with coefficients, i.e., the orientation distribution coefficients (ODC) as texture parameters. Three of these ODC's are of special interests, namely W400, W420, and W440. This paper includes results from ultrasonic NDE and this novel algorithm.—Ames Laboratory is operated for U.S. Department of Energy by Iowa State University under Contract W-7405-ENG-82. This work was supported by the Office of Basic Energy Sciences as a part of the Center of Excellence of the Synthesis and Processing of Advanced Materials.

  1. High cycle fatigue characteristics of 2124-T851 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    LI Xue; YIN Zhimin; NIE Bo; ZHONG Li; PAN Qinglin; JIANG Feng

    2007-01-01

    The fatigue crack growth rate, fracture toughness and fatigue S-N curve of 2124-T851 aluminum alloy at high cycle fatigue condition were measured and fatigue fracture process and fractography were studied using optical microscopy (OM), X-ray diffraction (XRD) technique, trans-mission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that at room tempera-ture and R = 0.1 conditions, the characteristics of fatigue fracture could be observed. Under those conditions, the fatigue strength and the fracture toughness of a 2124-T851 thick plate is 243 MPa and 29.64 MPa·m1/2,respectively.At high cycle fatigue condition, the higher the stress amplitude,the wider the space between fatigue striations, the faster the rate of fatigue crack developing and going into the intermittent fracture area, and the greater the ratio between the intermittent fracture area and the whole fracture area.

  2. Laser Surface Alloying of Copper, Manganese, and Magnesium with Pure Aluminum Substrate

    Science.gov (United States)

    Jiru, Woldetinsay G.; Sankar, M. Ravi; Dixit, Uday S.

    2016-03-01

    Laser surface alloying is one of the recent technologies used in the manufacturing sector for improving the surface properties of the metals. Light weight materials like aluminum alloys, titanium alloys, and magnesium alloys are used in the locomotive, aerospace, and structural applications. In the present work, an experimental study was conducted to improve the surface hardness of commercially pure aluminum plate. CO2 laser is used to melt pre-placed powders of pure copper, manganese, and magnesium. Microstructure of alloyed surface was analyzed using optical microscope. The best surface alloying was obtained at the optimum values of laser parameters, viz., laser power, scan speed, and laser beam diameter. In the alloyed region, microhardness increased from 30 HV0.5 to 430 HV0.5, while it was 60 HV0.5 in the heat-affected region. Tensile tests revealed some reduction in the strength and total elongation due to alloying. On the other hand, corrosion resistance improved.

  3. Interface properties and phase formation between surface coated SKD61 and aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Se-Weon CHOI; Young-Chan KIM; Se-Hun CHANG; Ik-Hyun OH; Joon-Sik PARK; Chang-Seog KANG

    2009-01-01

    The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting process. The surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 ℃ for 10 h and the e-FeSi phase formed. When the coated SKD61 alloy was dipped in the liquid aluminum alloy (ALDC12), the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys, i.e., the intermediate phases (FeSiAl compound) were not produced for the coated SKD61 alloy. The coating layer of e-FeSi served as a diffusion barrier for the formation of FeSiAl compounds.

  4. Effects of zincate treatment on adhesion of electroless Ni-P coating onto various aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Makoto HINO; Koji MURAKAMI; Yutaka MITOOKA; Ken MURAOKA; Teruto KANADANI

    2009-01-01

    The effects of alloying elements on zincate treatment and adhesion of electroless Ni-P coating onto various aluminum alloy substrates were examined. Surface morphology of zinc deposits in the 1st zincate treatment and its adhesion were changed depending on the alloying element. The zinc deposits in the 2nd zincate treatment became thinly uniform, and the adhesion between aluminum alloy substrate and Ni-P coating was improved irrespective of the alloying element. XPS analysis revealed the existence of zinc on the surface of each aluminum alloy substrate after the pickling in 5% nitric acid. This zinc on the surface should be an important factor influencing the morphology of zinc deposit at the 2nd zincate treatment and its adhesion.

  5. Formability analysis of aluminum alloys through deep drawing process

    Science.gov (United States)

    Pranavi, U.; Janaki Ramulu, Perumalla; Chandramouli, Ch; Govardhan, Dasari; Prasad, PVS. Ram

    2016-09-01

    Deep drawing process is a significant metal forming process used in the sheet metal forming operations. From this process complex shapes can be manufactured with fewer defects. Deep drawing process has different effectible process parameters from which an optimum level of parameters should be identified so that an efficient final product with required mechanical properties will be obtained. The present work is to evaluate the formability of Aluminum alloy sheets using deep drawing process. In which effects of punch radius, lubricating conditions, die radius, and blank holding forces on deep drawing process observed for AA 6061 aluminum alloy sheet of 2 mm thickness. The numerical simulations are performed for deep drawing of square cups using three levels of aforesaid parameters like lubricating conditions and blank holding forces and two levels of punch radii and die radii. For numerical simulation a commercial FEM code is used in which Hollomon's power law and Hill's 1948 yield criterions are implemented. The deep drawing setup used in the FEM code is modeled using a CAD tool by considering the modeling requirements from the literature. Two different strain paths (150x150mm and 200x200mm) are simulated. Punch forces, thickness distributions and dome heights are evaluated for all the conditions. In addition failure initiation and propagation is also observed. From the results, by increasing the coefficient of friction and blank holding force, punch force, thickness distribution and dome height variations are observed. The comparison has done and the optimistic parameters were suggested from the results. From this work one can predict the formability for different strain paths without experimentation.

  6. Long-term strategies for increased recycling of automotive aluminum and its alloying elements.

    Science.gov (United States)

    Løvik, Amund N; Modaresi, Roja; Müller, Daniel B

    2014-04-15

    Aluminum recycling currently occurs in a cascading fashion, where some alloys, used in a limited number of applications, absorb most of the end-of-life scrap. An expected increase in scrap supply in coming decades necessitates restructuring of the aluminum cycle to open up new recycling paths for alloys and avoid a potential scrap surplus. This paper explores various interventions in end-of-life management and recycling of automotive aluminum, using a dynamic substance flow analysis model of aluminum and its alloying elements with resolution on component and alloy level (vehicle-component-alloy-element model). It was found that increased component dismantling before vehicle shredding can be an effective, so far underestimated, intervention in the medium term, especially if combined with development of safety-relevant components such as wheels from secondary material. In the long term, automatic alloy sorting technologies are most likely required, but could at the same time reduce the need for magnesium removal in refining. Cooperation between the primary and secondary aluminum industries, the automotive industry, and end-of-life vehicle dismantlers is therefore essential to ensure continued recycling of automotive aluminum and its alloying elements.

  7. Al-Si alloy point contact formation and rear surface passivation for silicon solar cells using double layer porous silicon

    Science.gov (United States)

    Moumni, Besma; Ben Jaballah, Abdelkader; Bessais, Brahim

    2012-10-01

    Lowering the rear surface recombination velocities by a dielectric layer has fascinating advantages compared with the standard fully covered Al back-contact silicon solar cells. In this work the passivation effect by double layer porous silicon (PS) (wide band gap) and the formation of Al-Si alloy in narrow p-type Si point contact areas for rear passivated solar cells are analysed. As revealed by Fourier transform infrared spectroscopy, we found that a thin passivating aluminum oxide (Al2O3) layer is formed. Scanning electron microscopy analysis performed in cross sections shows that with bilayer PS, liquid Al penetrates into the openings, alloying with the Si substrate at depth and decreasing the contact resistivity. At the solar cell level, the reduction in the contact area and resistivity leads to a minimization of the fill factor losses.

  8. Evaluation of Sc-Bearing Aluminum Alloy C557 for Aerospace Applications

    Science.gov (United States)

    Domack, Marcia S.; Dicus, Dennis L.

    2002-01-01

    The performance of the Al-Mg-Sc alloy C557 was evaluated to assess its potential for a broad range of aerospace applications, including airframe and launch vehicle structures. Of specific interest were mechanical properties at anticipated service temperatures and thermal stability of the alloy. Performance was compared with conventional airframe aluminum alloys and with other emerging aluminum alloys developed for specific service environments. Mechanical properties and metallurgical structure were evaluated for commercially rolled sheet in the as-received H116 condition and after thermal exposures at 107 C. Metallurgical analyses were performed to de.ne grain morphology and texture, strengthening precipitates, and to assess the effect of thermal exposure.

  9. In-plane anisotropy of 1545 aluminum alloy sheet

    Institute of Scientific and Technical Information of China (English)

    PENG Yong-yi; YIN Zhi-min; YANG Jin; DU Yu-xuan

    2005-01-01

    The microstructures and the tensile mechanical properties in the rolling plane of 1545 aluminum alloy sheet at different orientations with respect to the rolling direction were studied by means of tensile test,X-ray diffractometer(XRD),optical microscope and transmission electron microscope.The in-plane anisotropy of tensile mechanical properties was calculated and the inverse pole figures of the rolling plane,transversal section and longitudinal section were obtained by Harris method.The results show that the 1545 Al alloy sheet has remarkable in-plane anisotropy of mechanical properties and the main texture component is{110}texture.On the basis of the model that regards the sheet containing only{110}texture as a monocrystal,the relationship of in-plane anisotropy and the anisotropy of crystallography was analyzed.The study shows that it is the combined effects of the anisotropy of crystallography and microstructures that cause the in-plane anisotropy of mechanical properties,but the main cause is the crystallographic texture.

  10. Semi-solid metal processing of aluminum alloy A356 and magnesium alloy AZ91: Comparison based on metallurgical consideration

    Energy Technology Data Exchange (ETDEWEB)

    Kleiner, S.; Beffort, O. [Swiss Federal Laboratories for Materials Testing and Research, EMPA Thun, CH-3602 Thun (Switzerland); Ogris, E.; Uggowitzer, P.J. [Institute of Metallurgy, ETH Swiss Federal Institute of Technology, CH-8092 Zuerich (Switzerland)

    2003-09-01

    Thixocasting or rheocasting of AZ and AM magnesium alloys continues to be a problematic case in semi-solid processing. The comparison with the aluminum thixo alloy A356 shows that the metallurgical and physical properties of the Mg alloy AZ91 are little compatible with this technology: The conclusions from this study are of fundamental importance for future developments in this field of research. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  11. Study on Hot Deformation Behavior of 7085 Aluminum Alloy during Backward Extrusion Process

    Directory of Open Access Journals (Sweden)

    R. B. Mei

    2015-01-01

    Full Text Available Compression test was carried out and the true stress-strain curves were obtained from the hot compression of 7085 alloy. A numerical simulation on the deformation behavior of 7085 aluminum alloy during the backward extrusion was also performed by finite element method. The results show that dynamic recrystallization occurs in the hot compression of 7085 alloy and the peak stress reaches higher values as the strain rate increases and deformation temperature decreases. The backward extrusion processes include contact deformation, initial deformation, and steady deformation. Severe plastic deformation of shear and compression occurs when the metal flowed into the channel between fillet of punch and wall of die so that the grain size can be refined by backward extrusion. The deformation in the region of top of wall is too small to meet the mechanical properties of requirements and the metal usually needs to be trimmed. The experiments with the same parameters as simulation had been carried out and the experimental cup after extrusion has better quality.

  12. Aluminum-Lithium Alloy 2050 for Reduced-Weight, Increased-Stiffness Space Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Touchstone Research Laboratory, along with Alcan Rolled Products ? Ravenswood WV, has identified the Aluminum-Lithium Alloy 2050 as a potentially game-changing...

  13. The mechanism of stress-corrosion cracking in 7075 aluminum alloy

    Science.gov (United States)

    Jacobs, A. J.

    1970-01-01

    Various aspects of stress-corrosion cracking in 7075 aluminum alloy are discussed. A model is proposed in which the continuous anodic path along which the metal is preferentially attacked consists of two phases which alternate as anodes.

  14. WAYS TO IMPROVE SEDIMENTATION STABILITY OF RELEASE COATING FOR DIE CASTING OF ALUMI-NUM ALLOYS

    Directory of Open Access Journals (Sweden)

    A. A. Pivovarchyk

    2015-01-01

    Full Text Available The paper presents the results of a study on the effect of a method for dispersing the size of the component of the dispersed phase separation coatings used in high pressure die casting aluminum alloys.

  15. Computational Modeling aided Near Net Shape Manufacturing for Aluminum Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will focus on developing and validating computational models for near-net shape processing of aluminum alloys. Computational models will be developed...

  16. Simulation of 3D chip shaping of aluminum alloy 7075 in milling processes

    Institute of Scientific and Technical Information of China (English)

    DONG Hui-yue; KE Ying-lin

    2005-01-01

    By adopting an equivalent geometry model of machining process and considering thermo-plastic properties of the work material, a finite element method(FEM) to study oblique milling process of aluminum alloy with a double-edge tool was presented. In the FEM, shear flow stress was determined by material test. Re-meshing technology was used to represent chip separation process. Comparing the predicted cutting forces with the measured forces shows the 3D FEM is reasonable. Using this FEM, chip forming process and temperature distribution were predicted. Chips obtained by the 3D FEM are in spiral shape and are similar to the experimental ones. Distribution and change trend of temperature in the tool and chip indicate that contact length between tool rake face and chip is extending as tool moving forward. These results confirm the capability of FEM simulation in predicting chip flow and selecting optimal tool.

  17. A novel simple approach to preparation of superhydrophobic surfaces of aluminum alloys

    Science.gov (United States)

    Xie, Degang; Li, Wen

    2011-11-01

    A novel two-step methodology is successfully developed to fabricate superhydrophobic surfaces of aluminum alloys. The essential procedure is that samples are first immersed and etched in a boiling aqueous solution of NaOH for 5 min without preprocessing, and then they are modified for 30 min in an ethanol solution of lauric acid, cheaper and more efficient than the fluorinated silane frequently adopted by other researchers. If the concentration of NaOH solution is larger than 5 g/L, the contact angle of the prepared surfaces will be larger than 150° with a negligible hysteresis. Such a fast, low-cost, and reliable method for superhydrophobic surfaces implies significant promising industrial applications.

  18. Superplasticity of the aluminum alloys containing the Al{sub 3}Ni eutectic particles

    Energy Technology Data Exchange (ETDEWEB)

    Portnoy, V.K. [Department of Physical Metallurgy Non-Ferrous Metals, National University of Science and Technology ' ' MISIS' ' , Moscow (Russian Federation); Mikhaylovskaya, A.V.

    2012-09-15

    The structures and parameters of superplasticity of aluminum alloys containing fine and coarse eutectic Al{sub 3}Ni particles were investigated. Traditional hot and cold rolling were used for sheet producing. The research alloys have low- or high - alloying solid solution. Superplasticity characterization of the alloy with high-alloying solid solution is much better beside alloys with low-alloying solid solution. Alloying by zirconium improves superplasticity in some investigated alloys. Some alloys with partially recrystallized structure show d = 500-700% at T = 0.95 Tm with the constant strain rates to the range of (1.10{sup -3}-1.10{sup -2}) s{sup -1}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Fabrication of Aluminum Tubes Filled with Aluminum Alloy Foam by Friction Welding

    Directory of Open Access Journals (Sweden)

    Yoshihiko Hangai

    2015-10-01

    Full Text Available Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting of ADC12 Al-Si-Cu die-cast aluminum alloy foam and a dense A1050 commercially pure Al tube with metal bonding were fabricated by friction welding. First, it was found that the ADC12 precursor was firmly bonded throughout the inner wall of the A1050 tube without a gap between the precursor and the tube by friction welding. No deformation of the tube or foaming of the precursor was observed during the friction welding. Next, it was shown that by heat treatment of an ADC12-precursor-bonded A1050 tube, gases generated by the decomposition of the blowing agent expand the softened ADC12 to produce the ADC12 foam interior of the dense A1050 tube. A holding time during the foaming process of approximately tH = 8.5 min with a holding temperature of 948 K was found to be suitable for obtaining a sound ADC12-foam-filled A1050 tube with sufficient foaming, almost uniform pore structures over the entire specimen, and no deformation or reduction in the thickness of the tube.

  20. Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.

    1995-01-01

    Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

  1. Advanced powder metallurgy aluminum alloys via rapid solidification technology, phase 2

    Science.gov (United States)

    Ray, Ranjan; Jha, Sunil C.

    1987-01-01

    Marko's rapid solidification technology was applied to processing high strength aluminum alloys. Four classes of alloys, namely, Al-Li based (class 1), 2124 type (class 2), high temperature Al-Fe-Mo (class 3), and PM X7091 type (class 4) alloy, were produced as melt-spun ribbons. The ribbons were pulverized, cold compacted, hot-degassed, and consolidated through single or double stage extrusion. The mechanical properties of all four classes of alloys were measured at room and elevated temperatures and their microstructures were investigated optically and through electron microscopy. The microstructure of class 1 Al-Li-Mg alloy was predominantly unrecrystallized due to Zr addition. Yield strengths to the order of 50 Ksi were obtained, but tensile elongation in most cases remained below 2 percent. The class 2 alloys were modified composition of 2124 aluminum alloy, through addition of 0.6 weight percent Zr and 1 weight percent Ni. Nickel addition gave rise to a fine dispersion of intermetallic particles resisting coarsening during elevated temperature exposure. The class 2 alloy showed good combination of tensile strength and ductility and retained high strength after 1000 hour exposure at 177 C. The class 3 Al-Fe-Mo alloy showed high strength and good ductility both at room and high temperatures. The yield and tensile strength of class 4 alloy exceeded those of the commercial 7075 aluminum alloy.

  2. Commercialization of NASA's High Strength Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    In this paper, the commercialization of a new high strength cast aluminum alloy, invented by NASA-Marshall Space Flight Center, for high temperature applications will be presented. Originally developed to meet U.S. automotive legislation requiring low- exhaust emission, the novel NASA aluminum alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (450 F-750 F), which can lead to reducing part weight and cost as well as improving performance for automotive engine applications. It is an ideal low cost material for cast components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. NASA alloy also offers greater wear resistance, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys, and the new alloy can be produced economically from sand, permanent mold and investment casting. Since 2001, this technology was licensed to several companies for automotive and marine internal combustion engines applications.

  3. Numerical simulation of different pulse width of long pulsed laser on aluminum alloy

    Science.gov (United States)

    Li, Mingxin; Jin, Guangyong; Zhang, Wei; Chen, Guibo; Bi, Juan

    2015-03-01

    Established a physical model to simulate the melt ejection induced by long pulsed laser on aluminum alloy and use the finite element method to simulate the whole process. This simulation is based on the interaction between single pulsed laser with different pulse width and different peak energy and aluminum alloy material. By comparing the theoretical simulation data and the actual test data, we discover that: the theoretical simulation curve is well consistent with the actual experimental curve, this two-dimensional model is with high reliability; when the temperature at the center of aluminum alloy surface increases and evaporation happens after the surface temperature at the center of aluminum alloy surface reaches boiling point and later the aluminum alloy material sustains in the status of equilibrium vaporization; the keyhole appears on the surface of the target, an increment of the keyhole, the maximum temperature at the center of aluminum alloy surface gradually moves inwardly. This research may provide the theoretical references to the understanding of the interaction between millisecond pulsed laser and many kinds of materials, as well as be beneficial to the application of the laser materials processing and military field.

  4. Machining studies of die cast aluminum alloy-silicon carbide composites

    Science.gov (United States)

    Sornakumar, Thambu; Kathiresan, Marimuthu

    2010-10-01

    Metal matrix composites (MMCs) with high specific stiffness, high strength, improved wear resistance, and thermal properties are being increasingly used in advanced structural, aerospace, automotive, electronics, and wear applications. Aluminum alloy-silicon carbide composites were developed using a new combination of the vortex method and the pressure die-casting technique in the present work. Machining studies were conducted on the aluminum alloy-silicon carbide (SiC) composite work pieces using high speed steel (HSS) end-mill tools in a milling machine at different speeds and feeds. The quantitative studies on the machined work piece show that the surface finish is better for higher speeds and lower feeds. The surface roughness of the plain aluminum alloy is better than that of the aluminum alloy-silicon carbide composites. The studies on tool wear show that flank wear increases with speed and feed. The end-mill tool wear is higher on machining the aluminum alloy-silicon carbide composites than on machining the plain aluminum alloy.

  5. Temperature rise and wear of sliding contact of alloy steels

    Science.gov (United States)

    Goswami, Arindam Roy; Sardar, Santanu; Karmakar, Santanu Kumar

    2016-07-01

    The tribo-failure of machine elements under relative sliding velocities is greatly affected by frictional heating and resultant contact temperature rise. Nevertheless, the tribo-failure of automotive components is a combined effect of mechanical, thermal and chemical phenomena. Over the decades, there have been developed a number of different mathematical models for predicting surface temperature rise at sliding contact under different geometries of asperity contacts and operating conditions. The experimental investigation is still relevant today to find out the surface temperature rise at sliding contact along with the outcomes of friction and wear under various operating conditions for real time applications. The present work aims at finding average surface temperature rise at different sliding velocities, normal loads with different surface roughness experimentally. It also involves to prepare two different rough surfaces of alloy steels and to study their influences in the process of generating contact temperature rise under a given operating conditions.

  6. A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Liming Liu

    2014-05-01

    Full Text Available Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research.

  7. Measurement and control of ice adhesion to aluminum 6061 alloy

    Science.gov (United States)

    Archer, Paul; Gupta, Vijay

    1998-10-01

    A new experimental strategy for measuring the tensile strength of ice coatings to structural surfaces is presented. In this experiment, a laser-induced compressive stress pulse travels through a 1 mm-thick substrate disc that has a layer of ice grown on its front surface. The compressive stress pulse reflects into a tensile wave from the free surface of the ice and pulls the iceinterface apart, given a sufficient amplitude. The interface strength was calculated by recording the free surface velocity of an Al substrate using a Doppler interferometer and calculating the stress at the interface using a finite-difference elastic wave mechanics simulation with the free surface velocity as an input. The test procedure was used to study ice adhesion on 6061 aluminum alloy sheets. It was found that the adhesion strength of ice to unpolished aluminum substrates was 274 MPa at -10°C. This value decreased with temperature, down to 179 MPa at -40°C. Interestingly, this decrement in the tensile strength could be directly related to the existence of a liquid-like layer that is known to exist on the surface of solid ice till -30°C. The interface strength was also shown to decrease by polishing the Al substrate surface or by adding thin polymer coatings on the unpolished Al substrate. The sensitivity of the technique to such microstructural changes in the interfacial region is indicative of the experiments ability to provide basic adhesion data, which in turn, can be used to solve the deicing problem from a fundamental standpoint. 1998 Elsevier Science Ltd.

  8. Diffusion Bonding and Characterization of a Dispersion Strengthened Aluminum Alloy

    Science.gov (United States)

    Cooke, Kavian Omar

    Aluminum metal matrix composites (Al-MMC's) containing silicon carbide or alumina particle reinforcements are used extensively in automotive and aircraft industries. The addition of a reinforcing phase has led to significant improvements in the mechanical properties of these alloys. However, despite substantial improvements in the properties, the lack of a reliable joining method has restricted their full potential. The differences in physical and metallurgical properties between the ceramic phase and the Al-MMC, prevents the successful application of the fusion welding processes, conventionally used for joining monolithic aluminum alloys. Therefore, alternative techniques that prevent microstructural changes in the base metal need to be developed. In this study, the transient liquid phase diffusion bonding and eutectic bonding of a particle reinforced Al 6061-MMC was investigated to identify a method that could control particle segregation within the joint and increase the final joint strength. The results showed that TLP bonding using Ni-foil was possible at 600°C for 10 minutes using a pressure of 0.01 MPa. However, characterization of the bond interface showed a wide particle segregated zone due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The presence of this particle segregated zone was shown to cause low joint strengths. In order to overcome these problems, TLP bonding was performed using electrodeposited coatings of Ni and Ni-Al 2O3 as a way of controlling the volume of eutectic liquid formed at the joint. Theoretical and experimental work showed that the use of thin coatings was successful in reducing the width of the segregated zone formed at the joint and this had the effect of increasing joint shear strength values. Furthermore, lower bonding temperature could also be used as a method of reducing particle segregation and therefore, a Cu-Sn interlayer was used to form a eutectic bond. The

  9. Selection Of Cutting Inserts For Aluminum Alloys Machining By Using MCDM Method

    Science.gov (United States)

    Madić, Miloš; Radovanović, Miroslav; Petković, Dušan; Nedić, Bogdan

    2015-07-01

    Machining of aluminum and its alloys requires the use of cutting tools with special geometry and material. Since there exists a number of cutting tools for aluminum machining, each with unique characteristics, selection of the most appropriate cutting tool for a given application is very complex task which can be viewed as a multi-criteria decision making (MCDM) problem. This paper is focused on multi-criteria analysis of VCGT cutting inserts for aluminum alloys turning by applying recently developed MCDM method, i.e. weighted aggregated sum product assessment (WASPAS) method. The MCDM model was defined using the available catalogue data from cutting tool manufacturers.

  10. Studies on the effect of vibration on hot cracking and Grain size in AA7075 Aluminum alloy Welding

    OpenAIRE

    2011-01-01

    The aim of this present study is to investigate the vibration effect which is applied during Gas tungsten Arc welding (GTAW) welding in order to improve the quality of high strength Aluminum alloy weldment. An important metallurgical difficulty in arc welding of high strength aluminum alloys is formation of hot cracking. When Aluminum alloy is welded by GTAW process, weld fusion zone shows coarse columnar grains during weld metal solidification. This often leads to poor resistance to hot crac...

  11. Corrosion Behavior of Commercial Aluminum Alloy Processed by Equal Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    Atef Korchef

    2013-01-01

    Full Text Available A commercial aluminum alloy was subjected to severe plastic deformation through equal channel angular pressing (ECAP. The alloy contains a low volume fraction of α-AlFeSi located essentially at the grain boundaries. The corrosion behavior of the ECAP’ed alloy was investigated in NaCl solution using potentiodynamic polarization and immersion tests. The effects of scan rate and NaCl concentration on the alloy susceptibility to corrosion were also studied. The results obtained were compared with those of the nonpressed alloy. ECAP leads to an intensive grain refinement accompanied by an increased dislocation density. All electrochemical tests confirm that corrosion resistance of the alloy remarkably diminished with increasing the ECAP number of passes. This is presumably due to the breakdown of the α-AlFeSi after ECAP leading to higher number of galvanic cells and enhanced dissolution of the aluminum matrix.

  12. Iron-aluminum alloys having high room-temperature and method for making same

    Science.gov (United States)

    Sikka, V.K.; McKamey, C.G.

    1993-08-24

    A wrought and annealed iron-aluminum alloy is described consisting essentially of 8 to 9.5% aluminum, an effective amount of chromium sufficient to promote resistance to aqueous corrosion of the alloy, and an alloying constituent selected from the group of elements consisting of an effective amount of molybdenum sufficient to promote solution hardening of the alloy and resistance of the alloy to pitting when exposed to solutions containing chloride, up to about 0.05% carbon with up to about 0.5% of a carbide former which combines with the carbon to form carbides for controlling grain growth at elevated temperatures, and mixtures thereof, and the balance iron, wherein said alloy has a single disordered [alpha] phase crystal structure, is substantially non-susceptible to hydrogen embrittlement, and has a room-temperature ductility of greater than 20%.

  13. Accelerated corrosion test and corrosion failure distribution model of aircraft structural aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-lin; MU Zhi-tao; JIN Ping

    2006-01-01

    Based on corrosion damage data of 10 years for a type of aircraft aluminum alloy, the statistical analysis was conducted by Gumbel, Normal and two parameters Weibull distribution function. The results show that aluminum alloy structural member has the corrosion history of pitting corrosion-intergranular corrosion-exfoliation corrosion, and the maximum corrosion depth is in conformity to normal distribution. The accelerated corrosion test was carried out with the complied equivalent airport accelerated environment spectrum. The corrosion damage failure modes of aluminum alloy structural member indicate that the period of validity of the former protective coating is about 2.5 to 3 years, and that of the novel protective coating is about 4.0 to 4.5 years. The corrosion kinetics law of aluminum spar flange was established by fitting corrosion damage test data. The law indicates two apparent corrosion stages of high strength aluminum alloy section material: pitting corrosion and intergranular corrosion/exfoliation corrosion.The test results agree with the statistical fit result of corrosion data collected from corrosion member in service. The fractional error is 5.8% at the same calendar year. The accelerated corrosion test validates the corrosion kinetics law of aircraft aluminum alloy in service.

  14. A Numerical Formula for General Prediction of Interface Bonding between Alumina and Aluminum-Containing Alloys

    Directory of Open Access Journals (Sweden)

    Michiko Yoshitake

    2014-01-01

    Full Text Available Interface termination between alumina and aluminum-containing alloys is discussed from a viewpoint of thermodynamics by extending the authors’ previous discussion on the interface termination between alumina and pure metal. A numerical formula to predict interface bonding at alumina-aluminum-containing alloys is proposed. The effectiveness of the formula is examined by extracting information on interface termination from experimental results and first-principle calculations in references. It is revealed that the prediction by the formula agrees quite well with the results reported in the references. According to the formula, a terminating species can be switched from oxygen to aluminum, which had been actually demonstrated experimentally. The formula uses only basic quantities of pure elements and the formation enthalpy of oxides. Therefore it can be applied for most of aluminum-containing alloys in the periodic table and is useful for material screening in developing interfaces with particular functions.

  15. Several braze filler metals for joining an oxide-dispersion-strengthened nickel-chromium-aluminum alloy

    Science.gov (United States)

    Gyorgak, C. A.

    1975-01-01

    An evaluation was made of five braze filler metals for joining an aluminum-containing oxide dispersion-strengthened (ODS) alloy, TD-NiCrAl. All five braze filler metals evaluated are considered suitable for joining TD-NiCrAl in terms of wettability and flow. Also, the braze alloys appear to be tolerant of slight variations in brazing procedures since joints prepared by three sources using three of the braze filler metals exhibited similar brazing characteristics and essentially equivalent 1100 C stress-rupture properties in a brazed butt-joint configuration. Recommendations are provided for brazing the aluminum-containing ODS alloys.

  16. Influence of Post Weld Heat Treatment on Strength of Three Aluminum Alloys Used in Light Poles

    OpenAIRE

    Craig C. Menzemer; Eric Hilty; Shane Morrison; Ray Minor; Tirumalai S. Srivatsan

    2016-01-01

    The conjoint influence of welding and artificial aging on mechanical properties were investigated for extrusions of aluminum alloy 6063, 6061, and 6005A. Uniaxial tensile tests were conducted on the aluminum alloys 6063-T4, 6061-T4, and 6005A-T1 in both the as-received (AR) and as-welded (AW) conditions. Tensile tests were also conducted on the AR and AW alloys, subsequent to artificial aging. The welding process used was gas metal arc (GMAW) with spray transfer using 120–220 A of current at ...

  17. Correlation between shear punch and tensile data for neutron-irradiated aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, M.L.; Edwards, D.J. [Pacific Northwest Laboratory, Richland, WA (United States); Toloczko, M.B. [Univ. of California, Santa Barbara, CA (United States)] [and others

    1995-04-01

    This work was performed to determine whether shear punch and tensile data obtained on neutron irradiated aluminum alloys exhibited the same type of relationship as had been seen in other work and to assess the validity of extrapolating the results to proton-irradiated alloys. This work was also meant to be the first of a series of similar test matrices designed to determine whether the shear punch/tensile relationship varied or was the same for different alloy classes.

  18. Sensors Array Technique for Monitoring Aluminum Alloy Spot Welding

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; LUO Zhen; SHAN Ping; BU Xianzheng; YUAN Shuxian; AO Sansan

    2010-01-01

    In this paper, the sensors array technique is applied to the quality detection of aluminum alloy spot weld-ing. The sensors array has three forms, i.e., linear magnetic sensors array, annular magnetic sensors array and cross magnetic sensors array. An algorithm based on principal component analysis is proposed to extract the signal eigen-values. The three types of magnetic sensors array are used in the experiment of monitoring the signal. After the eigen-values are extracted, they are used to build a relationship with the nugget information. The result shows that when the distance between the core of the array and the pole is 60 mm, the arrays work best. In this case, when the eigenvalues' range of the linear array is 0.006 5-0.015 1, the quality of the spots is eligible. To the annular and cross array, when the ranges are 0.082 9—0.131 6 and 0.085 1—0.098 2 respectively, the nugget quality is eligible.

  19. Friction stir welding of 5052 aluminum alloy plates

    Institute of Scientific and Technical Information of China (English)

    Yong-Jai KWON; Seong-Beom SHIM; Dong-Hwan PARK

    2009-01-01

    Friction stir welding between 5052 aluminum alloy plates with a thickness of 2 mm was performed. The tool for welding was rotated at speeds ranging from 500 to 3 000 r/min under a constant traverse speed of 100 mm/min. The results show that at all tool rotation speeds, defect-free welds are successfully obtained. Especially at 1 000, 2 000 and 3 000 r/min, the welds exhibit very smooth surface morphologies. At 500, 1 000, and 2 000 r/min, onion ring structure is clearly observed in the friction-stir-welded zone (SZ). In addition, the onion ring structure region becomes wider as the tool rotation speed is increased. The gain size in the SZ is smaller than that in the base metal, and is decreased with a decrease of the tool rotation speed. In all tool rotation speeds, the SZ exhibits higher average hardness than the base metal. Especially at 500 r/min, the average hardness of the SZ reaches a level about 33% greater than that of the base metal. At 500, 1 000 and 2 000 r/min, the tensile strength of the friction stir welded (FSWed) plates is similar to that of the base metal (about 204 Mpa). The elongation of the FSWed plates is lower than that of the base metal (about 22%). However, it is noticeable that the maximum elongation of about 21% is obtained at 1 000 r/min.

  20. Tool For Friction Stir Tack Welding of Aluminum Alloys

    Science.gov (United States)

    Bjorkman, Gerald W.; Dingler, Johnny W.; Loftus, Zachary

    2003-01-01

    A small friction-stir-welding tool has been developed for use in tack welding of aluminum-alloy workpieces. It is necessary to tack-weld the workpieces in order to hold them together during friction stir welding because (1) in operation, a full-size friction-stir-welding tool exerts a large force that tends to separate the workpieces and (2) clamping the workpieces is not sufficient to resist this force. It is possible to tack the pieces together by gas tungsten arc welding, but the process can be awkward and time-consuming and can cause sufficient damage to necessitate rework. Friction stir tack welding does not entail these disadvantages. In addition, friction stir tack welding can be accomplished by use of the same automated equipment (except for the welding tool) used in subsequent full friction stir welding. The tool for friction stir tack welding resembles the tool for full friction stir welding, but has a narrower shoulder and a shorter pin. The shorter pin generates a smaller workpiece-separating force so that clamping suffices to keep the workpieces together. This tool produces a continuous or intermittent partial-penetration tack weld. The tack weld is subsequently consumed by action of the larger tool used in full friction stir welding tool.

  1. Ultrasonic measurement of residual stress in shot peened aluminum alloy

    Science.gov (United States)

    Lavrentyev, Anton I.; Veronesi, William A.

    2001-04-01

    Shot peening is a well-known method for extending the fatigue life of metal components by introducing compressive residual stresses near their surfaces. The capability to non-destructively evaluate the near surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper addresses issues encountered in near-surface residual stress measurement by an ultrasonic surface wave method. In this method, a variation of ultrasonic surface wave speed with shot peening intensity is measured. Since the effective wave penetration depth inversely related to the excitation frequency, by making measurements at different frequencies, the method has the potential to provide the stress-depth profile. Experiments were conducted on aluminum specimens (alloy 7075-T7351) peened within the Almen peening intensity from 4A-16A. Several factors were found to contribute to the measured responses: surface roughness, near surface texture change, dislocation density increase and residual stress. In this paper, the contributions of residual stress, dislocation density and surface roughness to the overall effect are separately estimated. It is shown that the experimentally observed velocity change in shot peened samples is dominated by the effect of surface roughness while the role of residual stress is much smaller.

  2. Numerical simulation of high speed incremental forming of aluminum alloy

    Science.gov (United States)

    Giuseppina, Ambrogio; Teresa, Citrea; Luigino, Filice; Francesco, Gagliardi

    2013-12-01

    In this study, an innovative process is analyzed with the aim to satisfy the industrial requirements, such as process flexibility, differentiation and customizing of products, cost reduction, minimization of execution time, sustainable production, etc. The attention is focused on incremental forming process, nowadays used in different fields such as: rapid prototyping, medical sector, architectural industry, aerospace and marine, in the production of molds and dies. Incremental forming consists in deforming only a small region of the workspace through a punch driven by a NC machine. SPIF is the considered variant of the process, in which the punch gives local deformation without dies and molds; consequently, the final product geometry can be changed by the control of an actuator without requiring a set of different tools. The drawback of this process is its slowness. The aim of this study is to assess the IF feasibility at high speeds. An experimental campaign will be performed by a CNC lathe with high speed to test process feasibility and the influence on materials formability mainly on aluminum alloys. The first results show how the material presents the same performance than in conventional speed IF and, in some cases, better material behavior due to the temperature field. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process substantially confirming experimental evidence.

  3. Influence of Shot Peening on Failure of an Aluminum Alloy Exposed to Aggressive Aqueous Environments

    Science.gov (United States)

    Lv, Shengli; Cu, You; Zhang, Wei; Tong, Xiaoyan; Srivatsan, T. S.; Gao, Xiaosheng

    2013-06-01

    Pre-corrosion damage tests were performed on the high strength aluminum alloy (Al-Zn-Mg-Cu) that was subject to shot peening surface treatment. The tests were performed for different time levels and compared one-on-one with the performance and characteristics of the non-shot-peened alloy. The residual stress induced by the shot peening surface treatment for two different intensity levels was measured using the method of incremental drilling of holes. Based on an observation of morphology of corrosion experienced by the aluminum alloy the depth of corrosion was measured using a laser displacement sensor. The surface of the aluminum alloy that was shot peened revealed an overall better resistance to pitting while concurrently revealing evidence of partial degradation. The depth of degradation is related to the residual stress that is induced in the aluminum alloy sample by the shot peening treatment. The key mechanisms that control damage during corrosion of the shot-peened aluminum alloy can be divided into the distinct stages of (a) initial occurrence of uniform corrosion followed by (b) the generation of degradation, and (c) culminating in the initiation of pitting once the depth of degradation reaches a certain level.

  4. Adhesion enhancement of titanium nitride coating on aluminum casting alloy by intrinsic microstructures

    Science.gov (United States)

    Nguyen, Chuong L.; Preston, Andrew; Tran, Anh T. T.; Dickinson, Michelle; Metson, James B.

    2016-07-01

    Aluminum casting alloys have excellent castability, high strength and good corrosion resistance. However, the presence of silicon in these alloys prevents surface finishing with conventional methods such as anodizing. Hard coating with titanium nitride can provide wear and corrosion resistances, as well as the aesthetic finish. A critical factor for a durable hard coating is its bonding with the underlying substrate. In this study, a titanium nitride layer was coated on LM25 casting alloy and a reference high purity aluminum substrate using Ion Assisted Deposition. Characterization of the coating and the critical interface was carried out by a range of complementing techniques, including SIMS, XPS, TEM, SEM/EDS and nano-indentation. It was observed that the coating on the aluminum alloy is stronger compared to that on the pure aluminum counterpart. Silicon particles in the alloy offers the reinforcement though mechanical interlocking at microscopic level, even with nano-scale height difference. This reinforcement overcomes the adverse effect caused by surface segregation of magnesium in aluminum casting alloys.

  5. ANALYSIS OF SURFACE DEFECTS OF ALUMINUM AND ITS ALLOYS WITH A SCANNING KELVIN PROBE

    Directory of Open Access Journals (Sweden)

    A. K. Tyavlovsky

    2017-01-01

    Full Text Available Currently, the use of probe electrometry in non-destructive testing is constrained by the complexity of measurement results interpretation. An output signal of electrometric probe depends on a number of physical and chemical parameters of surface including chemical composition variations, stresses, dislocations, crystallographic orientation of a surface, etc. The study aims to the use of probe electrometry methods for nondestructive testing and analysis of precision metal surfaces’ defects after different treatment or processing.Control of surface defects of aluminum and its alloys was performed with a scanning Kelvin probe technique. The results of scanning were plotted in a form of contact potential difference (CPD distribution map. Additionally, a histogram of CPD values distribution and statistical characteristics including the expectation of CPD mean value and histogram half-width were calculated either for the whole distribution or for each individual mode in a case of multimodal distribution.The spatial CPD distribution of A99 aluminum and AMG-2 alloy surfaces after electrochemical polishing and diamond finishing was studied. An additional study was held for AMG-2 surface after the formation of 30 microns thick specific nanostructured alumina oxide surface layer. Higher quality surfaces have characterized as more homogeneous distribution of the physical properties (at half-width distribution histogram. Surfaces with higher mechanical strength and overall better mechanical properties found to have lower CPD values that correspond to higher electron work function and surface energy. The presence of the second mode in the CPD distribution histogram indicates the significant proportion of defect areas on the sample surface.Analysis of visualized CPD distribution maps using defined criteria allows detecting and characterizing such defects as residual stress areas, areas with reduced microhardness, surface contamination spots, corrosion

  6. 铝及铝合金TIG焊接特性%Character of TIG Welding for Aluminum and Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    殷春喜; 黄军庆; 熊震东; 贾翠催

    2011-01-01

    The characters of TIG welding for aluminum and aluminum alloys were described, it includes the shielding gas and groove of TIG welding and the effect of welding process on the weld shape and welding quality.%概述了铝及铝合金TIG焊接技术特性,包括铝及铝合金TIG焊接保护气体、坡口的选择和焊接工艺对焊缝成形和焊接质量的影响.

  7. Development of Deformation-Semisolid-Casting (D-SSC) Process and Applications to Some Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Recent advances in the semisolid casting technologies are introduced for aluminum alloys. The advantages of the rheocast and thixocast methods to fabricate alloys with refined spheroidized α-Al particles are described.The deformation-semisolid-casting (D-SSC) process developed by the author's group is presented. The D-SSC process is extremely effective to produce microstructures of refined intermetallic compound particles as well as the spheroidized α-Al particles in the Al-Si based alloys containing highly concentrated Fe. In the D-SSC processed Al-Si-Cu alloy high elongation of about 20% was achieved even contained concentrated impurity of Fe. The D-SSC process is also useful to produce wrought aluminum alloys with microstructures of refined α-Al particles.

  8. Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Patricia Gómez

    2016-05-01

    Full Text Available The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe, Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe, Al Si9Cu3(Fe(Zn and Al Si9 has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10−1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe(Zn, with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

  9. A New Creep Constitutive Model for 7075 Aluminum Alloy Under Elevated Temperatures

    Science.gov (United States)

    Lin, Y. C.; Jiang, Yu-Qiang; Zhou, Hua-Min; Liu, Guan

    2014-12-01

    Exposure of aluminum alloy to an elastic loading, during "creep-aging forming" or other manufacturing processes at relatively high temperature, may lead to the lasting creep deformation. The creep behaviors of 7075 aluminum alloy are investigated by uniaxial tensile creep experiments over wide ranges of temperature and external stress. The results show that the creep behaviors of the studied aluminum alloy strongly depend on the creep temperature, external stress, and creep time. With the increase of creep temperature and external stress, the creep strain increases quickly. In order to overcome the shortcomings of the Bailey-Norton law and θ projection method, a new constitutive model is proposed to describe the variations of creep strain with time for the studied aluminum alloy. In the proposed model, the dependences of creep strain on the creep temperature, external stress, and creep time are well taken into account. A good agreement between the predicted and measured creep strains shows that the established creep constitutive model can give an accurate description of the creep behaviors of 7075 aluminum alloy. Meanwhile, the obtained stress exponent indicates that the creep process is controlled by the dislocation glide, which is verified by the microstructural observations.

  10. Thin-walled aluminum alloy tube NC precision bending based on finite element simulation

    Institute of Scientific and Technical Information of China (English)

    GU Rui-jie; YANG He; ZHAN Mei; LI Heng

    2006-01-01

    Elongation and springback are the bottleneck problems of thin-walled aluminum alloy tube NC precision bending. So thin-walled aluminum alloy tube NC precision bending based on finite element simulation is put forward. The finite element model of thin-walled aluminum alloy tube NC bending is established based on the DYNAFORM platform. The process of thin-walled aluminum alloy tube NC precision bending is simulated with the model and the elongation and springback of tube bending can be is put forward and the computing equations of bending angle, bending radius, blanking length and initial bending section based on elongation and springback angle are derived. The bending angle, bending radius, blanking length and initial bending section of tube bending can be gained with these equations based on the elongation and springback angle from the simulation. The study can be used to control the quality of thin-walled aluminum alloy tube NC bending so that precision bending without redundance can be realized.

  11. Study on shear resistance of aluminum alloy I-section members

    Institute of Scientific and Technical Information of China (English)

    Zhen DONG; Qilin ZHANG

    2008-01-01

    The design method for the shear resistance of aluminum alloy I-section members is presented, taking into consideration of the post-buckling strength of webs and the restraint effect of flanges, and the practical design formulas are proposed. The deflection of aluminum alloy I-section members under concentrated load is simulated by using the finite element method, and several design theories are discussed. The relation of shear resistance to the maximum web displacement reflects that the web of aluminum alloy I-section member is under fewer shears buckling force, while the whole member has higher shear resistance. However, the traditional design method is not able to give the real shear resistance of aluminum alloy I-section members. The proposed design formulas for the shear resistance of aluminum alloy I-section members is used to calculate accurately the post-buckling resistance of webs and the shear resistance contribution of flanges. The results are in a great agreement with the test data of Hamoodi M J, Burr C A, Evans H R and the results from Eurocode9 formulas.

  12. Determination of dynamic shear strength of 2024 aluminum alloy under shock compression

    Directory of Open Access Journals (Sweden)

    H. S. Zhang

    2016-04-01

    Full Text Available A series of plate impact shock-reshock and shock-release experiments were conducted by using an one-stage light gas gun to determine the critical shear strength of the 2024 aluminum alloy under shock compression levels ranging from 0.66 to 3.05 GPa in the present study. In the experiments, a dual flyer plate assembly, i.e., the 2024 aluminum alloy flyer backed either by a brass plate or a PMMA plate, was utilized to produce reshock or release wave. The stress profiles of uniaxial plane strain wave propagation in the 2024 aluminum alloy sample under different pre-compressed states were measured by the embedded stress gauges. The stress-strain data at corresponding states were then calculated by a Lagrangian analysis method named as path line method. The critical shear strengths at different stress levels were finally obtained by self-consistent method. The results show that, at the low shock compression level (0.66 to 3.05 GPa, the critical shear strength of the 2024 aluminum alloy cannot be ignored and increases with the increasing longitudinal stress, which may be attributed to rate-dependence and/or pressure dependent yield behavior of the 2024 aluminum alloy.

  13. Material characterization and finite element simulations of aluminum alloy sheets during non-isothermal forming process

    Science.gov (United States)

    Zhang, Nan

    The utilization of more non-ferrous materials is one of the key factors to succeed out of the constantly increasing demand for lightweight vehicles in automotive sector. Aluminum-magnesium alloys have been identified as the most promising substitutions to the conventional steel without significant compromise in structural stiffness and strength. However, the conventional forming methods to deform the aluminum alloy sheets are either costly or insufficient in formability which limit the wide applications of aluminum alloy sheets. A recently proposed non-isothermal hot stamping approach, which is also referred as Hot Blank - Cold Die (HB-CD) stamping, aims at fitting the commercial grade aluminum alloy sheets, such as AA5XXX and AA7XXX, into high-volume and cost-effective production for automotive sector. In essence, HB-CD is a mutation of the conventional hot stamping approach for boron steel (22MnB5) which deforms the hot blank within the cold tool set. By elevating the operation temperature, the formability of aluminum alloy sheets can be significantly improved. Meanwhile, heating the blank only and deforming within the cold tool sets allow to reduce the energy and time consumed. This research work aims at conducting a comprehensive investigation of HB-CD with particular focuses on material characterization, constitutive modeling and coupled thermo-mechanical finite element simulations with validation. The material properties of AA5182-O, a popular commercial grade of aluminum alloy sheet in automotive sector, are obtained through isothermal tensile testing at temperatures from 25° to 300°, covering a quasi-static strain-rate range (0.001--0.1s-1). As the state-of-the-art non-contact strain measurement technique, digital image correlation (DIC) system is utilized to evaluate the stress-strain curves as well as to reveal the details of material deformation with full-field and multi-axis strain measurement. Material anisotropy is characterized by extracting the

  14. Copper, Aluminum and Nickel: A New Monocrystalline Orthodontic Alloy

    Science.gov (United States)

    Wierenga, Mark

    Introduction: This study was designed to evaluate, via tensile and bend testing, the mechanical properties of a newly-developed monocrystalline orthodontic archwire comprised of a blend of copper, aluminum, and nickel (CuAlNi). Methods: The sample was comprised of three shape memory alloys; CuAlNi, copper nickel titanium (CuNiTi), and nickel titanium (NiTi); from various orthodontic manufacturers in both 0.018" round and 0.019" x 0.025" rectangular dimensions. Additional data was gathered for similarly sized stainless steel and beta-titanium archwires as a point of reference for drawing conclusions about the relative properties of the archwires. Measurements of loading and unloading forces were recorded in both tension and deflection testing. Repeated-measure ANOVA (alpha= 0.05) was used to compare loading and unloading forces across wires and one-way ANOVA (alpha= 0.05) was used to compare elastic moduli and hysteresis. To identify significant differences, Tukey post-hoc comparisons were performed. Results: The modulus of elasticity, deflection forces, and hysteresis profiles of CuAlNi were significantly different than the other superelastic wires tested. In all tests, CuAlNi had a statistically significant lower modulus of elasticity compared to the CuNiTi and NiTi wires (P <0.0001). The CuAlNi wire exhibited significantly lower loading and unloading forces than any other wire tested. In round wire tensile tests, loading force at all deflections was significantly lower for CuAlNi than CuNiTi or NiTi (P <0.0001). In tensile testing, the CuAlNi alloy was able to recover from a 7 mm extension (10% elongation) without permanent deformation and with little to no loss in force output. In large-deflection bend tests at 4, 5, and 6 mm deflection, CuAlNi showed the significantly lowest loading forces across the three wire materials (P <0.0001). The NiTi wires showed up to 12 times the amount of energy loss due to hysteresis compared to CuAlNi. CuAlNi showed a hysteresis

  15. Pore structure and mechanical properties of directionally solidified porous aluminum alloys

    Directory of Open Access Journals (Sweden)

    Komissarchuk Olga

    2014-01-01

    Full Text Available Porous aluminum alloys produced by the metal-gas eutectic method or GASAR process need to be performed under a certain pressure of hydrogen, and to carry over melt to a tailor-made apparatus that ensures directional solidification. Hydrogen is driven out of the melt, and then the quasi-cylindrical pores normal to the solidification front are usually formed. In the research, the effects of processing parameters (saturation pressure, solidification pressure, temperature, and holding time on the pore structure and porosity of porous aluminum alloys were analyzed. The mechanical properties of Al-Mg alloys were studied by the compressive tests, and the advantages of the porous structure were indicated. By using the GASAR method, pure aluminum, Al-3wt.%Mg, Al-6wt.%Mg and Al-35wt.%Mg alloys with oriented pores have been successfully produced under processing conditions of varying gas pressure, and the relationship between the final pore structure and the solidification pressure, as well as the influences of Mg quantity on the pore size, porosity and mechanical properties of Al-Mg alloy were investigated. The results show that a higher pressure of solidification tends to yield smaller pores in aluminum and its alloys. In the case of Al-Mg alloys, it was proved that with the increasing of Mg amount, the mechanical properties of the alloys sharply deteriorate. However, since Al-3%Mg and Al-6wt.%Mg alloys are ductile metals, their porous samples have greater compressive strength than that of the dense samples due to the existence of pores. It gives the opportunity to use them in industry at the same conditions as dense alloys with savings in weight and material consumption.

  16. Influence of Mg and Ti on the microstructure and electrochemical performance of aluminum alloy sacrificial anodes

    Institute of Scientific and Technical Information of China (English)

    MA Jingling; WEN Jiuba; LI Xudong; ZHAO Shengli; YAN Yanfu

    2009-01-01

    The experiments focused on the influence of magnesium and titanium as additional alloying elements on the microstructure and electro-chemical behavior of Al-Zn-ln sacrificial anodes. The electrochemical behavior of the aluminum sacrificial anode with 3 wt.% sodium chlo-fide solution was studied by electrochemical impedance spectroscopy (EIS) tests. It was found that a microstructure with few precipitates and refined grains could be achieved by adding 1 wt.% Mg and 0.05 wt.% Ti to the Al-Zn-In alloy, resulting in the improved current capacity and efficiency of the alloy. The equivalent circuit based on the EIS experimental data revealed less corrosion and lower adsorbed corrosion pro-duction on the surface of the aluminum alloy with a combination of 1 wt.% Mg and 0.05 wt.% Ti, which suggested that the corrosion behav-ior seemed to be strongly related to the presence of precipitate particles in the aluminum alloy, and moderate amounts of precipitate particles could be beneficial to the electrochemical performance of the aluminum alloy sacrificial anode.

  17. 用稀土合金对铸造铝合金精炼和变质处理的研究%A New Approach to Refining and Modifying Cast Aluminum Alloys with Rare Earth Alloys

    Institute of Scientific and Technical Information of China (English)

    唐多光; 毛协民

    2000-01-01

    The effects of rare earth (RE) alloys on the refining and modifying of cast aluminum alloys were investigated. Compared to other substances in common use, rare earth alloys maintain the refining and modifying effects of the aluminum alloys for a longer time. RE alloys can also reduce environmental pollution in the melting process. These effects of RE alloys make them become a superior choice for the applications in aluminum foundry.

  18. A Study on Friction Stir Welding of 12mm Thick Aluminum Alloy Plates

    Institute of Scientific and Technical Information of China (English)

    Deepati Anil Kumar; Pankaj Biswas; Sujoy Tikader; M. M. Mahapatra; N. R. Mandal

    2013-01-01

    Most of the investigations regarding friction stir welding (FSW) of aluminum alloy plates have been limited to about 5 to 6 mm thick plates. In prior work conducted the various aspects concerning the process parameters and the FSW tool geometry were studied utilizing friction stir welding of 12 mm thick commercial grade aluminum alloy. Two different simple-to-manufacture tool geometries were used. The effect of varying welding parameters and dwell time of FSW tool on mechanical properties and weld quality was examined. It was observed that in order to achieve a defect free welding on such thick aluminum alloy plates, tool having trapezoidal pin geometry was suitable. Adequate tensile strength and ductility can be achieved utilizing a combination of high tool rotational speed of about 2000 r/min and low speed of welding around 28 mm/min. At very low and high dwell time the ductility of welded joints are reduced significantly.

  19. A new dynamic method for measuring hydrogen partial pressure in molten aluminum alloy

    Directory of Open Access Journals (Sweden)

    Sun Qian

    2011-02-01

    Full Text Available Hydrogen partial pressure is an important parameter to calculate hydrogen concentration levels in molten aluminum alloy. A new dynamic method for measuring hydrogen partial pressure in molten aluminum alloy is studied. Dynamic and rapid measurement is realized through changing the volume of the vacuum chamber and calculating the pressure difference ΔP between the theoretical and measured pressures in the vacuum chamber. Positive ΔP indicates hydrogen transmits from melt to vacuum chamber and negative ΔP means the reverse. When ΔP is equal to zero, hydrogen transmitted from both sides reached a state of dynamical equilibrium and the pressure in the vacuum chamber is equal to the hydrogen partial pressure in the molten aluminum alloy. Compared with other existing measuring methods, the new method can significantly shorten the testing time and reduce measuring cost.

  20. Effect of Multi-repair Welding on Fatigue Performance of Aluminum Alloy Profile Welded Joint

    Science.gov (United States)

    Diao, You-De; Shi, Chun-Yuan; Tian, Hong-Lei

    2016-05-01

    Aluminum alloy profile has been widely used in the manufacture of the rail vehicles. But it's necessary for the repair welding of the welded joints to be conducted because some defects exist in the weld such as porosity, inclusions and incomplete penetrations in the welding processes. In this paper, the influence of the multi-repair welding of 6005A aluminum alloy profile butt welded joints on the fatigue performance are investigated based on the results of fatigue tests. The parameters of curves and the fatigue strength of the welded joints are calculated, and Goodman fatigue limit diagram is also obtained. The results show that fatigue strength of aluminum alloy profile butt welded joints, in condition of 107 cycle life, meet the standard requirement for the as-welded, repair welded state one time or two times respectively.

  1. Welding Distortion Prediction in 5A06 Aluminum Alloy Complex Structure via Inherent Strain Method

    Directory of Open Access Journals (Sweden)

    Zhi Zeng

    2016-09-01

    Full Text Available Finite element (FE simulation with inherent deformation is an ideal and practical computational approach for predicting welding stress and distortion in the production of complex aluminum alloy structures. In this study, based on the thermal elasto-plastic analysis, FE models of multi-pass butt welds and T-type fillet welds were investigated to obtain the inherent strain distribution in a 5A06 aluminum alloy cylindrical structure. The angular distortion of the T-type joint was used to investigate the corresponding inherent strain mechanism. Moreover, a custom-designed experimental system was applied to clarify the magnitude of inherent deformation. With the mechanism investigation of welding-induced buckling by FE analysis using inherent deformation, an application for predicting and mitigating the welding buckling in fabrication of complex aluminum alloy structure was developed.

  2. Numerical and experimental study of phase transformation in resistance spot welding of 6082 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    TANG Xinxin; SHA Ping; LUO Zhen; LUO Baofa

    2009-01-01

    Resistance spot welding(RSW) is an efficient and convenient joining process for aluminum alloy sheet assembly. Because the RSW has the character of energy concentration and quick cooling rate, the microstructure transformation of the base metal can be confined in the least limit. The material properties and the welding parameters have significant effects on thequality of the nugget. To predict the microstructure evolution in the melted zone and the heat-affected zone, an electrical, thermal, metallurgical and mechanical coupled finite element model is described and applied to simulate the welding process of the 6082 aluminum alloy. Experimental tests are also carried out. The comparison between experimental and numerical results shows that the adopted model is effective enough to well interpret and predict some important phenomena in terms of the phase transformation in spot welding of 6082 aluminum alloy.

  3. Preparation of three-dimensional shaped aluminum alloy foam by two-step foaming

    Energy Technology Data Exchange (ETDEWEB)

    Shang, J.T. [Key laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096 (China)], E-mail: Jshang@seu.edu.cn; Xuming, Chu; Deping, He [School of Materials Science and Engineering, Southeast University, Nanjing 210096 (China)

    2008-06-25

    A novel method, named two-step foaming, was investigated to prepare three-dimensional shaped aluminum alloy foam used in car industry, spaceflight, packaging and related areas. Calculations of thermal decomposition kinetics of titanium hydride showed that there is a considerable amount of hydrogen releasing when the titanium hydride is heated at a relatively high temperature after heated at a lower temperature. The hydrogen mass to sustain aluminum alloy foam, having a high porosity, was also estimated by calculations. Calculations indicated that as-received titanium hydride without any pre-treatment can be used as foaming agents in two-step foaming. The processes of two-step foaming, including preparing precursors and baking, were also studied by experiments. Results showed that, low titanium hydride dispersion temperature, long titanium hydride dispersion time and low precursors porosity are beneficial to prepare three-dimensional shaped aluminum alloy foams with uniform pores.

  4. The Cleaning of OAB Universal Covers - An Origin of Smut in Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shen, T

    2002-05-14

    The smut that appeared on the universal covers after the OAB cleaning process consists of sub-micron size aluminum particles originating from the machining of these parts prior to cleaning. The rigorous gross and precision cleanings with Brulin in the OAB cleaning process could not completely wash these fine particles away from the surfaces. However, applying a phosphoric acid etch before the cleaning helped to remove these fine aluminum particles. Experimental results again showed that an acid etching before cleaning is essential in preventing the occurrence of smut in aluminum alloy after gross/precision cleaning. A mechanism, based on the electrostatic {zeta}-potential, is proposed to explain the occurrence of smut that is often encountered during the cleaning of aluminum alloys.

  5. Numerical analysis of thermal effect in aluminum alloy by monopulse laser

    Science.gov (United States)

    Gu, Xiuying; Chen, Guibo; Jin, Guangyong; Zhang, Wei; Li, Mingxin

    2014-12-01

    A spatial axisymmetric finite element model is established to investigate the distribution characteristics of temperature field that monopulse millisecond laser act on aluminum alloy. The thermal process of laser acting on aluminum alloy (melting, gasification and temperature drop) is simulated. Using the specific quivalent heat capacity method to simulate the solid-liquid, liquid-gas phase transition of aluminum alloy, and considering the differences of thermal physical parameters between different states (solid-liquid, liquid-gas) of aluminum alloy in the process of numerical simulation. The distribution of temperature field of aluminum alloy caused by the change of energy density, pulse width and spot radius of monopulse millisecond laser are investigated systematically by using numerical simulation model. The numerical results show that the temperature of target no longer rises after reaching the target gasification. Given the pulse width and spot radius, the temperature of target rise as the energy density increases, the laser intensity distribution is gaussian, so the temperature distribution of the target surface also shows Gaussian. The energy absorption mechanism of aluminum alloy is surface absorption mechanism, the temperature gradient in axial of the target is much lager than the temperature gradient in radial of the target surface, so the temperature rise in axial only exists a thin layer of target surface. Given the energy density and spot radius, as the pulse width increases, the power density of laser decreases, therefore the temperature of target center point decreases as the pulse width increases, and the temperature difference becomes small. As the pulse width decreases, the heat transfer in axial reduce, the deposition of energy enhances on the surface. Given the energy density and pulse width, the distribution of the temperature is enlarged as the spot radius increases, but the distribution of the temperature in axial is independent of the spot

  6. The thickness of native oxides on aluminum alloys and single crystals

    OpenAIRE

    Evertsson, J.; Bertram, F.; Weissenrieder, J.; Goethelid, Mats; Pan, J; Mikkelsen, A.; Nilsson, J.-O.; Lundgren, E.; Zhang, F.; Rullik, L.; Merte, L. R.; Shipilin, Mikhail; Soldemo, M.; S Ahmadi; Vinogradov, N.

    2015-01-01

    We present results from measurements of the native oxide film thickness on four different industrial aluminum alloys and three different aluminum single crystals. The thicknesses were determined using X-ray reflectivity, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In addition, atomic force microscopy was used for micro-structural studies of the oxide surfaces. The reflectivity measurements were performed in ultra-high vacuum, vacuum, ambient, nitrogen and liq...

  7. Investigation of the Microstructure of Joints of Aluminum Alloys Produced by Friction Stir Welding

    Science.gov (United States)

    Kolubaev, E. A.

    2015-02-01

    Special features of the microstructure of joints of aluminum-magnesium and aluminum-copper alloys produced by friction stir welding are analyzed. It is demonstrated that a layered structure with ultradisperse grains is produced by friction stir welding at the center of the weld joint. An analogy is drawn between the microstructures of joints produced by friction stir welding and surface layer produced by sliding friction.

  8. Effect of temperature on corrosion behavior of 3003 aluminum alloy in ethylene glycol-water solution

    Institute of Scientific and Technical Information of China (English)

    Chen Xin; Tian Wenming; Li Songmei; Yu Mei; Liu Jianhua

    2016-01-01

    The effect of temperature on the corrosion behavior of 3003 aluminum alloy in ethylene glycol–water solution was investigated by potentiodynamic polarization and electrochemical impe-dance spectroscopy (EIS) techniques. The surface characterization was observed and determined by scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive spec-trometer (EDS). The results demonstrate that the anodic aluminum dissolution and the cathodic oxygen reduction were accelerated by the increased temperature. However, as temperature was over 60 °C, the solubility and concentration of oxygen decreased, resulting in the inhibition of cathodic reaction. The cathodic reaction rate of 3003 aluminum alloy rose to the maximum at 60 °C. The Warburg impedance in Nyquist diagram diminished and then was replaced by a negative capaci-tance caused by the absorption of intermediate corrosion product on electrode. On the other hand, after potentiodynamic measurements, 3003 aluminum alloy suffered pitting corrosion. The dissolu-tion of aluminum alloy around secondary phase particles expanded both horizontally and vertically. © 2016 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://creativecommons.

  9. Low temperature bonding of LD31 aluminum alloys by electric brush plating Ni and Cu coatings

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhenqing; Wang Chunqing; Du Miao

    2005-01-01

    Soldering of LD31 aluminum alloys using Sn-Pb solder paste after electric brush plating Ni and Cu coatings was nvestigated. The technology of electric brush plating Ni and Cu was studied and plating solution was developed. The microstructure of the coatings, soldered joint and fracture face were analyzed using optic microscopy, SEM and EDX. The shear strength of soldered joint could reach as high as 26. 83 MPa. The results showed that reliable soldered joint could be obtained at 230℃, the adhesion of coatings and LD31 aluminum alloy substrate was high enough to bear the thermal process in the soldering.

  10. Optimization of pulsed TIG welding process parameters on mechanical properties of AA 5456 Aluminum alloy weldments

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A. [Department of Mechanical Engineering, National Institute of Technology, Warangal 506 004 (India)], E-mail: adepu_kumar7@yahoo.co.in; Sundarrajan, S. [Scientist ' G' , Defence Research and Development Laboratory, Hyderabad 500 028 (India)

    2009-04-15

    The present work pertains to the improvement of mechanical properties of AA 5456 Aluminum alloy welds through pulsed tungsten inert gas (TIG) welding process. Taguchi method was employed to optimize the pulsed TIG welding process parameters of AA 5456 Aluminum alloy welds for increasing the mechanical properties. Regression models were developed. Analysis of variance was employed to check the adequacy of the developed models. The effect of planishing on mechanical properties was also studied and observed that there was improvement in mechanical properties. Microstructures of all the welds were studied and correlated with the mechanical properties.

  11. Constitutive description of casting aluminum alloy based on cylindrical void-cell model

    Institute of Scientific and Technical Information of China (English)

    CHEN Bin; PENG Xiang-he; ZENG Xiang-guo; WU Xin-yan; SUN Shi-tao

    2006-01-01

    Casting aluminum alloys are highly heterogeneous materials with different types of voids that affect the mechanical properties of the material. Through the analysis ora cylindrical void-cell model the evolution equation of the voids was obtained. The evolution equation was embedded into a nonclassical elastoplastic constitutive relation, and an elastoplastic constitutive relation involving void evolution was obtained. A corresponding finite element procedure was developed and applied to the analyses of the distributions of the axial stress and porosity of notched cylindrical specimens of casting aluminum alloy A101. The computed results show good agreement with experimental data.

  12. Influence of Density on Compressive Properties and Energy Absorption of Foamed Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    WEI Peng; LIU Lin

    2007-01-01

    The foamed aluminum alloys with different densities were fabricated by melt foaming technique. The compressive properties and energy absorption of the foamed aluminum alloy with different densities were analyzed. The results reveal that the compressive stress-strain curves follow the typical behavior of cellular foams with three deformation stages. Under the same strain, the energy absorption capability decreases with the decrease of density. However, with increasing the strain, the energy absorption efficiency of foamed metal increases initially and then decreases. The lower the density, the longer the plateau region, within the range of high strain, the energy absorption efficiency is always high.

  13. Multi-Response Optimization of Friction-Stir-Welded AA1100 Aluminum Alloy Joints

    Science.gov (United States)

    Rajakumar, S.; Balasubramanian, V.

    2012-06-01

    AA1100 aluminum alloy has gathered wide acceptance in the fabrication of light weight structures. Friction stir welding process (FSW) is an emerging solid state joining process in which the material that is being welded does not melt and recast. The process and tool parameters of FSW play a major role in deciding the joint characteristics. In this research, the relationships between the FSW parameters (rotational speed, welding speed, axial force, shoulder diameter, pin diameter, and tool hardness) and the responses (tensile strength, hardness, and corrosion rate) were established. The optimal welding conditions to maximize the tensile strength and minimize the corrosion rate were identified for AA1100 aluminum alloy and reported here.

  14. Thermal conductivity prediction of closed-cell aluminum alloy considering micropore effect

    Directory of Open Access Journals (Sweden)

    Donghui Zhang

    2015-02-01

    Full Text Available Large quantities of micro-scale pores are observed in the matrix of closed-cell aluminum alloy by scanning electron microscope, which indicates the dual-scale pore characteristics. Corresponding to this kind of special structural morphology, a new kind of dual-scale method is proposed to estimate its effective thermal conductivity. Comparing with the experimental results, the article puts forward the view that the prediction accuracy can be improved by the dual-scale method greatly. Different empirical formulas are also investigated in detail. It provides a new method for thermal properties estimation and makes preparation for more suitable empirical formula for closed-cell aluminum alloy.

  15. Study on quality of resistance spot welded aluminum alloys under various electrode pressures

    Institute of Scientific and Technical Information of China (English)

    San-san AO; Zhen LUO; Xin-xin TANG; Lin-shu ZHOU; Shu-xian YUAN; Rui WANG; Kai-lei SONG; Xing-zheng BU; Xiao-yi LI; Zhi-qing XUE

    2009-01-01

    The electrode force is One of the main parameters in resistance spot welding (RSW). It is very important to guarantee the quality of aluminum alloys and determine whether the electrode pressure is stable or adjustable in the welding process. With the drive set of a servo-motor, we conduct the RSW tests and tensile shear tests on the 5052 aluminum alloy sheets. Results of these tests show that all variable pressure curves are suitable for spot welding, and all have their own rules in affecting the tensile strength of the spot welded joints.

  16. Effect of Electromagnetic Frequency on Microstructures of Continuous Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The relationship between electromagnetic frequency and microstructures of continuous casting aluminum alloyswas studied. 7075 aluminum alloy ingot of 100 mm in diameter was produced by electromagnetic continuouscasting process, the microstructures of as-cast ingot was examined by scanning electron microscopy (SEM) equippedwith energy dispersive spectrometer (EDS). The results showed that electromagnetic frequency greatly influencedsegregation and microstructures of as-cast ingot, and product quality can be guaranteed by the application of aproper frequency. Electromagnetic frequency plays a significant role in solute redistribution; Iow frequency is moreefficient for promoting solution of alloying elements.

  17. ARTIFICIAL NEURAL NETWORK MODEL OF CONSTITUTIVE RELATIONSHIP FOR 2A70 ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    F. Liu; D.B. Shan; Y. Lu; Y.Y. Yang

    2005-01-01

    The hot deformation behavior of 2A70 aluminum alloy was investigated by means of isothermal compression tests performed on a Gleeble-1500 thermal simulator over a wide range of temperatures 360-480℃ with strain rates of 0.01-1s-1 and the largest deformation of 60%, and the true stress of the material was obtained under the above-mentioned conditions. The experimental results shows that 2A70 aluminum alloy is a kind of aluminum alloy with the property of dynamic recovery; its flow stress declines with the increase of temperature, while its flow stress increases with the increase of strain rates. On the basis of experiments, the constitutive relationship of the 2A70 aluminum alloy was constructed using a BP artificial neural network. Comparison of the predicted values with the experimental data shows that the relative error of the trained model is less than ±3% for the sampled data while it is less than ±6% for the nonsampled data. It is evident that the model constructed by BP ANN can accurately predict the flow stress of the 2A70 alloy.

  18. A Parametric Analysis of CO2 Laser Heat Absorption Profile of 5083 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    JOSEPH .I. ACHEBO

    2010-06-01

    Full Text Available Aluminum alloys are amongst the most difficult everyday metals that can be welded using the laser welding process. For this reason, high power density lasers are needed to weld these alloys because they require higher thermal diffusivity to form a key hole than would be needed for other metals such as steel. This means that more heat wouldhave to be applied while welding aluminum alloys than would be needed to weld steel to achieve a satisfactory coupling effect. The heat input generated from laser welding is affected by the absorptivity coefficient, the welding speed and the time spent. Once the optimum heat input is attained, it is expected to create less heat distortion, its energy is more concentrated within the weld area and deep weld penetration is achieved. Determining optimum values of welding parameters would lead to acceptable weld quality. In this study, the heat absorption profile of a CO2 laser welding of 5083 aluminum alloy was investigated using the models proposed by Bramson in 1968 and Okon et al in 2002. The 4mm thick aluminum alloy investigated was as received from the vendors. The calculated laser beam absorptivity coefficient, irradiance and boiling temperature were 0.12, 2.3 x 106 Wcm-2 and 2482oC respectively. These calculated values compared well with reported values in other literature.

  19. Aging Optimization of Aluminum-Lithium Alloy L277 for Application to Cryotank Structures

    Science.gov (United States)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Cho, A.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties and improved damage tolerance. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. A design of experiments aging study was conducted for plate and a limited study on extrusions. To achieve the T8 temper, Alloy L277 is typically aged at 290 F for 40 hours. In the study for plate, a two-step aging treatment was developed through a design of experiments study and the one step aging used as a control. Based on the earlier NASA studies on 2195, the first step aging temperature was varied between 220 F and 260 F. The second step aging temperatures was varied between 290 F and 310 F, which is in the range of the single-step aging temperature. For extrusions, two, single-step, and one two-step aging condition were evaluated. The results of the design of experiments used for the T8 temper as well as a smaller set of experiments for the T6 temper for plate and the results for extrusions will be presented.

  20. To find effects of GMAW parameters on Mechanical Properties of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Chandan Kaushal

    2014-11-01

    Full Text Available The present research aims to investigate the effects of Gas Metal Arc Welding (GMAW on the mechanical properties of different grades of aluminum alloys. GMAW is the most common method of joining aluminum alloys used in various industrial processes. It replaces the Tungsten Inert Gas (TIG method of providing equally high quality of joints with a much higher performance. Aluminum alloys under consideration for this experiment will be from 6XXX series, consisting of Silicon and Magnesium as main alloying elements. Weld joints Will be produced with the help of a Gas Metal Arc Welding (GMAW process. The Hardness, Tensile strength, yield stresses and elongation will be the mechanical properties to be obtained. As aluminum alloys show large micro structural changes after welding it is necessary to know about the effect of welding parameters on the mechanical properties of weldements as too high welding current and too high welding speed will result in high heat input and weakening of weld profile so a balance is need to be struck between welding parameters and mechanical properties. Scattering Electron Microscopy (SEM technique will be used to analyze micro structural changes.

  1. Evaluation of Aluminum Alloy 2050-T84 Microstructure and Mechanical Properties at Ambient and Cryogenic Temperatures

    Science.gov (United States)

    Hafley, Robert A.; Domack, Marcia S.; Hales, Stephen J.; Shenoy, Ravi N.

    2011-01-01

    Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of the incumbent aluminum alloy, 2195, which will enable designs with greater structural efficiency. While ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and fracture tests were conducted on 4 inch thick 2050-T84 plate at ambient temperature and at -320degF. Various metallurgical analyses were also performed in order to provide an understanding of the compositional homogeneity and microstructure of 2050.

  2. Quantitative analysis of impurities in aluminum alloys by laser-induced breakdown spectroscopy without internal calibration

    Institute of Scientific and Technical Information of China (English)

    LI Hong-kun; LIU Ming; CHEN Zhi-jiang; LI Run-hua

    2008-01-01

    To develop a fast and sensitive alloy elemental analysis method, a laser-induced breakdown spectroscopy(LIBS) system was established and used to carry out quantitative analysis of impurities in aluminum alloys in air at atmospheric pressure. A digital storage oscilloscope was used as signal recording instrument, instead of traditional gate integrator or Boxcar averager, to reduce the cost of the whole system. Linear calibration curves in the concentration range of 4×10-5-10-2 are built for Mg, Cr, Mn, Cu and Zn using absolute line intensity without internal calibrations. Limits of detection for these five elements in aluminum alloy are determined to be (2-90)×10-6. It is demonstrated that LIBS can provide quantitative trace elemental analysis in alloys even without internal calibration. This approach is easy to use in metallurgy industries and relative research fields.

  3. Microstructure and properties of 2618-Ti heat resistant aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    王建华; 易丹青; 王斌

    2003-01-01

    The mechanical properties of alloy 2618 with 0.5%(mass fraction) titanium and its microstructures in different states such as as-cast and quenching-aging were investigated. Titanium was added into the alloy with Al-5%Ti master alloy that was extruded severely. Al3Ti particles in the microstructure of cast alloy 2618-Ti are very small because those of master alloy are also small. When titanium is used as an alloying element, it does not affect the morphology of Al9FeNi phase in cast alloy, but decreases the grain size of as-cast alloy remarkably. The grain size of quenching-aging alloy 2618 decreases apparently due to the existence of a great deal of dispersive Al3Ti particles. Adding 0.5%Ti has no effect on the room temperature tensile properties of alloy 2618, but apparently increases the elevated temperature instantaneous tensile properties and that of the alloy which is exposed at 250 ℃ for 100 h.

  4. Hot hardness of nickel-rich nickel-chromium-aluminum alloys

    Science.gov (United States)

    Levine, S. R.

    1976-01-01

    Rockwell A hardness of cast nickel-chromium-aluminum (NiCrAl) alloys was examined from ambient to 1150 K and compared to cast NiAl and IN-100. Alloy constitution was either gamma, gamma prime + gamma or gamma + beta + alpha + gamma prime. Below 1000 K beta containing NiCrAl alloys have hardnesses comparable to IN-100; above 1000 K they soften faster than IN-100. At 1150 K the hardness of beta-containing NiCrAl alloys decreases with increasing beta-content. The beta-containing NiCrAl alloys were harder than beta-NiAl. The ultimate tensile strengths of the NiCrAl alloys were estimated. The effects of NiCrAl coatings on strength and fatigue life of cooled turbine components were deduced.

  5. Preparation of Al-Sr Master Alloy in Aluminum Electrolysis Cell

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Al-Sr master alloy was prepared by using liquid aluminum cathode and a mixture of Na3AlF6- SrCO3 as the basic molten salt electrolyte in a laboratory electrolysis cell.The effects of electrolyte composition,electrolysis temperature,cathodic current density and the electrolytic duration on Sr content of Al-Sr alloy were studied.Through laboratory experiments,the parameters for smooth electrolytic reaction were proposed.

  6. Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting

    OpenAIRE

    Juliana de Paula Martins; André Luis Moreira de Carvalho; Angelo Fernando Padilha

    2012-01-01

    A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC) process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1) to reduce the strip's thickness by 67%, and 2) to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001}

  7. Research on Semisolid Microstructural Evolution of 2024 Aluminum Alloy Prepared by Powder Thixoforming

    OpenAIRE

    Pubo Li; Tijun Chen; Suqing Zhang; Renguo Guan

    2015-01-01

    A novel method, powder thixoforming, for net-shape forming of the particle-reinforced Aluminum matrix composites in semi-solid state has been proposed based on powder metallurgy combining with thixoforming technology. The microstructural evolution and phase transformations have been investigated during partial remelting of the 2024 bulk alloy, prepared by cold pressing of atomized alloy powders to clarify the mechanisms of how the consolidated powders evolve into small and spheroidal primary...

  8. Crack Initiation and Growth Behavior at Corrosion Pit in 7075-T6 High Strength Aluminum Alloy

    Science.gov (United States)

    2013-06-01

    was not used to measure the transition from corrosion pit to long crack [25]. . . . . . . . . . . 22 3.1 Composition of a typical sample of 7075 -T6...lives. 24 III. Methodology 3.1 Material Research was conducted using 7075 -T6 aluminum. This alloy is commonly used in aerospace applications and as a... material properties of this alloy. It is important to note that these properties were also used in all finite element models. Table 3.1: Composition of

  9. Metallic Reinforcement of Direct Squeeze Die Casting Aluminum Alloys for Improved Strength and Fracture Resistance

    Energy Technology Data Exchange (ETDEWEB)

    D. Schwam: J.F. Wallace: Y. Zhu: J.W. Ki

    2004-10-01

    The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were

  10. Evolution of Surface Oxide Film of Typical Aluminum Alloy During Medium-Temperature Brazing Process

    Institute of Scientific and Technical Information of China (English)

    程方杰; 赵海微; 王颖; 肖兵; 姚俊峰

    2014-01-01

    The evolution of the surface oxide film along the depth direction of typical aluminum alloy under medium-temperature brazing was investigated by means of X-ray photoelectron spectroscopy (XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the en-richment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloy-ing elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during medium-temperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.

  11. Aging Optimization of Aluminum-Lithium Alloy C458 for Application to Cryotank Structures

    Science.gov (United States)

    Sova, B. J.; Sankaran, K. K.; Babel, H.; Farahmand, B.; Rioja, R.

    2003-01-01

    Compared with aluminum alloys such as 2219, which is widely used in space vehicle for cryogenic tanks and unpressurized structures, aluminum-lithium alloys possess attractive combinations of lower density and higher modulus along with comparable mechanical properties. These characteristics have resulted in the successful use of the aluminum-lithium alloy 2195 (Al-1.0 Li-4.0 Cu-0.4 Mg-0.4 Ag-0.12 Zr) for the Space Shuttle External Tank, and the consideration of newer U.S. aluminum-lithium alloys such as L277 and C458 for future space vehicles. These newer alloys generally have lithium content less than 2 wt. % and their composition and processing have been carefully tailored to increase the toughness and reduce the mechanical property anisotropy of the earlier generation alloys such 2090 and 8090. Alloy processing, particularly the aging treatment, has a significant influence on the strength-toughness combinations and their dependence on service environments for aluminum-lithium alloys. Work at NASA Marshall Space Flight Center on alloy 2195 has shown that the cryogenic toughness can be improved by employing a two-step aging process. This is accomplished by aging at a lower temperature in the first step to suppress nucleation of the strengthening precipitate at sub-grain boundaries while promoting nucleation in the interior of the grains. Second step aging at the normal aging temperature results in precipitate growth to the optimum size. A design of experiments aging study was conducted for plate. To achieve the T8 temper, Alloy C458 (Al-1.8 Li-2.7 Cu-0.3 Mg- 0.08 Zr-0.3 Mn-0.6 Zn) is typically aged at 300 F for 24 hours. In this study, a two-step aging treatment was developed through a comprehensive 24 full factorial design of experiments study and the typical one-step aging used as a reference. Based on the higher lithium content of C458 compared with 2195, the first step aging temperature was varied between 175 F and 250 F. The second step aging temperatures was

  12. Softening phenomenon during compression test in nanograined aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ko, S.H.; Jang, J.M.; Lee, W. [Korea Inst. of Industrial Technology, ChonAn (Korea)

    2005-07-01

    Al-Mg and Al-Mg-Cu alloys are known well to reveal superplasticity in tension at high temperatures. In this study, deformation behaviors of those alloys nanograined were investigated under compression test at room temperature. During plastic deformation softening phenomena occurred obviously in nanograined Al-1.5wt%Mg and Al-0.7wt%Mg-1.0wt%Cu alloys while slight strain hardening appeared in nanograined pure Al. These results suggest that the softening strongly depends on composition of alloys. The softening takes place over strain rate range from 10{sup -4} up to 10{sup -1}. (orig.)

  13. Precipitation hardening and hydrogen embrittlement of aluminum alloy AA7020

    Indian Academy of Sciences (India)

    Santosh Kumar; T K G Namboodhiri

    2011-04-01

    AA7020 Al–Mg–Zn, a medium strength aluminium alloy, is used in welded structures in military and aerospace applications. As it may be subjected to extremes of environmental exposures, including high pressure liquid hydrogen, it could suffer hydrogen embrittlement. Hydrogen susceptibility of alloy AA7020 was evaluated by slow strain-rate tensile testing, and delayed failure testing of hydrogen-charged specimens of air-cooled, duplexaged, and water-quenched duplex agedmaterials. The resistance to hydrogen embrittlement of the alloy was found to be in the order of air-cooled duplex aged alloy > as-received (T6 condition) > water quenched duplex aged material.

  14. Order/disorder in electrodeposited aluminum-titanium alloys

    Directory of Open Access Journals (Sweden)

    Stafford G.R.

    2003-01-01

    Full Text Available The composition, morphology, and crystallographic microstructure of Al-Ti alloys electrodeposited from two different chloroaluminate molten salt electrolytes were examined. Alloys containing up to 28 % atomic fraction Ti were electrodeposited at 150 °C from 2:1 AlCl3-NaCl with controlled additions of Ti2+. The apparent limit on alloy composition is proposed to be due to a mechanism by which Al3Ti forms through the reductive decomposition of [Ti(AlCl43]-. The composition of Al-Ti alloys electrodeposited from the AlCl3-EtMeImCl melt at 80 °C is limited by the diffusion of Ti2+ to the electrode surface. Alloys containing up to 18.4 % atomic fraction Ti are only obtainable at high Ti2+ concentrations in the melt and low current densities. Alloys electrodeposited from the higher temperature melt have an ordered L12 crystal structure while alloys of similar composition but deposited at lower temperature are disordered fcc. The appearance of antiphase boundaries in the ordered alloys suggests that the deposit may be disordered initially and then orders in the solid state, subsequent to the charge transfer step and adatom incorporation into the lattice. This is very similar to the disorder-trapping observed in rapidly solidified alloys. The measured domain size is consistent with a mechanism of diffusion-controlled doman growth at the examined deposition temperatures and times.

  15. Deposition of aluminum-magnesium alloys from electrolytes containing organo-aluminum complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lehmkuhl, H.; Mehler, K.; Bongard, H.; Tesche, B. [Max-Planck-Inst. fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Reinhold, B. [Audi AG Technische Entwicklung, Ingolstadt (Germany)

    2001-06-01

    Organo-aluminum compounds have been used for many years as electrolytes in the coating industry. In this communication the development of a galvanic process for generating aluminum-magnesium coatings from organometallic electrolyte systems is reported as well as results on physical properties like adhesion, ductility and corrosion resistance. (orig.)

  16. Effects of Aluminum on Hydrogen Solubility and Diffusion in Deformed Fe-Mn Alloys

    Directory of Open Access Journals (Sweden)

    C. Hüter

    2016-01-01

    Full Text Available We discuss hydrogen diffusion and solubility in aluminum alloyed Fe-Mn alloys. The systems of interest are subjected to tetragonal and isotropic deformations. Based on ab initio modelling, we calculate solution energies and then employ Oriani’s theory which reflects the influence of Al alloying via trap site diffusion. This local equilibrium model is complemented by qualitative considerations of Einstein diffusion. Therefore, we apply the climbing image nudged elastic band method to compute the minimum energy paths and energy barriers for hydrogen diffusion. Both for diffusivity and solubility of hydrogen, we find that the influence of the substitutional Al atom has both local chemical and nonlocal volumetric contributions.

  17. Laser Shock Peening of Aluminum Alloy 7050 for Fatigue Life Improvement

    Institute of Scientific and Technical Information of China (English)

    Qian; Ming; Lian; Ying; Zou; Shikun; Gong; Shuili

    2007-01-01

    The effects of laser shock peening (LSP) on improving fatigue life of aluminum alloy 7050 are investigated.Surface hardness is increased corresponding to a high dislocation density induced by LSP.The X-ray diffraction stress measurement shows that LSP results in prominent increase of surface compressive stress,quasi-symmetrically distributed in the laser peened region.The fatigue life of the alloy 7050 in rivet fastener hole structure is notably improved owing to LSP.The sequence of LSP and fastener hole preparation also influence the fatigue cycle life of the alloy.

  18. Microstructure and Strain Fatigue Dislocation Structure of 7075-RRA Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The microstructure and the strain fatigue dislocation substructure of 7075-RRA (Retrogression and Reaging) aluminum alloy have been studied by using transmission electron microscopy. From these, a competitive mechanism of cyclic microscopic softening/hardening is put forward to explain the relation between macroscopic cyclic stability behavior and microscopic substructure.

  19. Environmentally assisted crack growth rates of high-strength aluminum alloys

    Science.gov (United States)

    Connolly, Brain J.; Deffenbaugh, Kristen L.; Moran, Angela L.; Koul, Michelle G.

    2003-01-01

    The scope of this project is to evaluate the environmentally assisted long crack growth behavior of candidate high-strength aluminum alloys/tempers, specifically AA7150-T7751 and AA7040-T7651, for consideration as viable replacements/refurbishment for stress-corrosion cracking in susceptible AA7075-T6 aircraft components found in aging aircraft systems.

  20. Microstructure and mechanical properties of friction stir welded thin sheets of 2024-T4 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    LI Lian; TONG Jian-hua; WAN Fa-rong; LONG Yi

    2006-01-01

    Friction stir welding (FSW) is a new and promising welding processing that can produce low-cost and high-quality joints of aluminum alloys. 1 mm thick sheets of 2024-T4 aluminum alloys which are always used as building and decorating materials were welded by FSW. The microstrueture and mechanical properties of friction stir welded 1 mm thick sheets of 2024-T4 aluminum alloy were studied. It was found that the thinner the 2024 aluminum alloy, the larger the FSW technological parameters field. The grains size of weld nugget zone (WNZ) is approximately 10 times smaller than that of the parent material, but the second phase in the material is not refined apparently in the welding. The FS welded joints have about 40% higher yield strength than the parent material,but the elongation of FS welded joints is under about 50% of the parent material. The electron backscattered diffraction (EBSD)results show that there are much more low angle boundaries (LAB) in WNZ than that in parent material, which indicates that FSW causes a number of sub-grain structures in WNZ, and this is also the reason of the increase of yield strength and Vickers hardness of the welded joint.

  1. Low alloy additions of iron, silicon, and aluminum to uranium: a literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, R.L.

    1980-12-31

    A survey of the literature has been made on the experimental results of small additions of iron, silicon, and aluminum to uranium. Information is also included on the constitution, mechanical properties, heat treatment, and deformation of various binary and ternary alloys. 42 references, 24 figures, 13 tables.

  2. The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

    Science.gov (United States)

    Danford, M. D.

    1994-01-01

    The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

  3. Fatigue Strength Estimation Based on Local Mechanical Properties for Aluminum Alloy FSW Joints

    Directory of Open Access Journals (Sweden)

    Kittima Sillapasa

    2017-02-01

    Full Text Available Overall fatigue strengths and hardness distributions of the aluminum alloy similar and dissimilar friction stir welding (FSW joints were determined. The local fatigue strengths as well as local tensile strengths were also obtained by using small round bar specimens extracted from specific locations, such as the stir zone, heat affected zone, and base metal. It was found from the results that fatigue fracture of the FSW joint plate specimen occurred at the location of the lowest local fatigue strength as well as the lowest hardness, regardless of microstructural evolution. To estimate the fatigue strengths of aluminum alloy FSW joints from the hardness measurements, the relationship between fatigue strength and hardness for aluminum alloys was investigated based on the present experimental results and the available wide range of data from the references. It was found as: σa (R = −1 = 1.68 HV (σa is in MPa and HV has no unit. It was also confirmed that the estimated fatigue strengths were in good agreement with the experimental results for aluminum alloy FSW joints.

  4. Innovation Group Will Invest 20 Billion Yuan to Launch a Hard Aluminum Alloy Project

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>On November 20, the People’s Government of Tongliao City of Inner Mongolia, the People’s Government of Huolinguole City and Shandong-based Innovation Group signed an investment framework agreement on a new-type hard aluminum alloy project. Under the agreement

  5. Influence of Post Weld Heat Treatment on Strength of Three Aluminum Alloys Used in Light Poles

    Directory of Open Access Journals (Sweden)

    Craig C. Menzemer

    2016-03-01

    Full Text Available The conjoint influence of welding and artificial aging on mechanical properties were investigated for extrusions of aluminum alloy 6063, 6061, and 6005A. Uniaxial tensile tests were conducted on the aluminum alloys 6063-T4, 6061-T4, and 6005A-T1 in both the as-received (AR and as-welded (AW conditions. Tensile tests were also conducted on the AR and AW alloys, subsequent to artificial aging. The welding process used was gas metal arc (GMAW with spray transfer using 120–220 A of current at 22 V. The artificial aging used was a precipitation heat treatment for 6 h at 182 °C (360 °F. Tensile tests revealed the welded aluminum alloys to have lower strength, both for yield and ultimate tensile strength, when compared to the as-received un-welded counterpart. The beneficial influence of post weld heat treatment (PWHT on strength and ductility is presented and discussed in terms of current design provisions for welded aluminum light pole structures.

  6. Structure and properties of castable aluminum alloy MVTU-6 after laser treatment

    Science.gov (United States)

    Silaeva, V. I.; Smirnova, N. A.; Solov'eva, T. V.

    2008-01-01

    The effect of laser treatment modes on the structure and properties of high-strength castable aluminum alloy MVTU-6 of the Al-Si-Cu-Cd system developed at the Bauman Moscow State Technical University by a group of researchers headed by I. I. Sidorin is studied.

  7. State of residual stress in laser-deposited ceramic composite coatings on aluminum alloys

    NARCIS (Netherlands)

    Kadolkar, P. B.; Watkins, T. R.; De Hosson, J. Th. M.; Kooi, B. J.; Dahotre, N. B.

    2007-01-01

    The nature and magnitude of the residual stresses within laser-deposited titanium carbide (TiC) coatings on 2024 and 6061 aluminum (Al) alloys were investigated. Macro- and micro-stresses within the coatings were determined using an X-ray diffraction method. Owing to increased debonding between the

  8. XRD and TEM analysis of the microstructure in the brazing joint of 3003 cladding aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Tao Feng; Songnian Lou; Luhai Wu; Yajiang Li

    2005-01-01

    The material used in this experiment was 3003 cladding aluminum alloy, the cladding metal was 4004 aluminum alloy.The aluminum plate was brazed by means of vacuum brazing. The microstructure in the brazing joint was studied by means of X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The test result indicates that the suitable brazing technique parameters are brazing temperature, 628℃; keeping time, 10 min; vacuum degree, 6.5×10-4 Pa. XRD test indicates that there are new intermetallic compounds different from the base metal. TEM analysis indicates that Cu2Mg and Cu3Mn2Mg are formed in the brazing joint. The shape of Cu2Mg is irregular and the shape of Cu3Mn2Mg is circle, and there are tiny particles in it.

  9. Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis

    Directory of Open Access Journals (Sweden)

    H. M. Hajar

    2016-01-01

    Full Text Available The corrosion performance of aluminum alloy 5083 (AA5083 was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance (Rct value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value (Cdl is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix.

  10. Effect of Mold Coating Materials and Thickness on Heat Transfer in Permanent Mold Casting of Aluminum Alloys

    Science.gov (United States)

    Hamasaiid, A.; Dargusch, M. S.; Davidson, C. J.; Tovar, S.; Loulou, T.; Rezaï-Aria, F.; Dour, G.

    2007-06-01

    In permanent mold casting or gravity die casting (GDC) of aluminum alloys, die coating at the casting-mold interface is the most important single factor controlling heat transfer and, hence, it has the greatest influence on the solidification rate and development of microstructure. This investigation studies the influence of coating thickness, coating composition, and alloy composition on the heat transfer at the casting-mold interface. Both graphite and TiO2-based coatings have been investigated. Two aluminum alloys have been investigated: Al-7Si-0.3Mg and Al-9Si-3Cu. Thermal histories throughout the die wall have been recorded by fine type-K thermocouples. From these measurements, die surface temperatures and heat flux density have been evaluated using an inverse method. Casting surface temperature was measured by infrared pyrometry, and the interfacial heat-transfer coefficient (HTC) has been determined using these combined pieces of information. While the alloy is liquid, the coating material has only a weak influence over heat flow and the thermal contact resistance seems to be governed more by coating porosity and thickness. The HTC decreases as the coating thickness increases. However, as solidification takes place and the HTC decreases, the HTC of graphite coating remains higher than that of ceramic coatings of similar thickness. After the formation of an air gap at the interface, the effect of coating material vanishes. The peak values of HTC and the heat flux density are larger for Al-7Si-0.3Mg than for Al-9Si-3Cu. Consequently, the apparent solidification time of Al-9Si-3Cu is larger than that of Al-7Si-0.3Mg and it increases with coating thickness.

  11. Hybrid manufacturing processes for fusion welding and friction stir welding of aerospace grade aluminum alloys

    Science.gov (United States)

    Gegesky, Megan Alexandra

    Friction stir welding and processing can provide for joints in aerospace grade aluminum alloys that have preferable material properties as compared to fusion welding techniques. Aerospace grade aluminum alloys such as AA2024-T3 and AA7075-T6 are considered non-weldable by traditional fusion welding techniques. Improved mechanical properties over previously used techniques are usually preferable for aerospace applications. Therefore, by combining traditional fusion welding and friction stir processing techniques, it could be plausible to create more difficult geometries in manufactured parts instead of using traditional techniques. While this combination of fusion welding and friction stir processing is not a new technology, its introduction to aerospace grade aluminum alloys as well as non-weldable alloys, is new. This is brought about by a lowered required clamping force required by adding a fusion weld before a friction stir processing technique. The changes in properties associated with joining techniques include: microstructural changes, changes in hardness, tensile strength, and corrosion resistance. This thesis illustrates these changes for the non-weldable AA2024-T351 and AA7075-T651 as well as the weldable alloy AA5052-H32. The microhardness, tensile strength and corrosion resistance of the four processing states: base material, fusion welded material, friction stir welded material, and friction stir processed fusion welded material is studied. The plausibility of this hybrid process for the three different materials is characterized, as well as plausible applications for this joining technique.

  12. Corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments

    Science.gov (United States)

    Kusada, Kentaro

    The objective of this study is to evaluate corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments. Al5052-H3 and Al6061-T6 were selected as substrates, and HCLCoat11 and HCLCoat13 developed in the Hawaii Corrosion Laboratory were selected for the siloxane ceramic/polymer coatings. The HCLCoat11 is a quasi-ceramic coating that has little to no hydrocarbons in its structure. The HCLCoat13 is formulated to incorporate more hydrocarbons to improve adhesion to substrate surfaces with less active functionalities. In this study, two major corrosion evaluation methods were used, which were the polarization test and the immersion test. The polarization tests provided theoretical corrosion rates (mg/dm 2/day) of bare, HCLCoat11-coated, and HCLCoat13-coated aluminum alloys in aerated 3.15wt% sodium chloride solution. From these results, the HCLCoat13-coated Al5052-H3 was found to have the lowest corrosion rate which was 0.073mdd. The next lowest corrosion rate was 0.166mdd of the HCLCoat11-coated Al5052-H3. Corrosion initiation was found to occur at preexisting breaches (pores) in the films by optical microscopy and SEM analysis. The HCLCoat11 film had many preexisting breaches of 1-2microm in diameter, while the HCLCoat13 film had much fewer preexisting breaches of less than 1microm in diameter. However, the immersion tests showed that the seawater immersion made HCLCoat13 film break away while the HCLCoat11 film did not apparently degrade, indicating that the HCLCoat11 film is more durable against seawater than the HCLCoat13. Raman spectroscopy revealed that there was some degradation of HCLCoat11 and HCLCoat13. For the HCLCoat11 film, the structure relaxation of Si-O-Si linkages was observed. On the other hand, seawater generated C-H-S bonds in the HCLCoat13 film resulting in the degradation of the film. In addition, it was found that the HCLCoat11 coating had anti-fouling properties due to its high water contact

  13. Finite Element Simulation of Temperature and Strain Distribution during Friction Stir Welding of AA2024 Aluminum Alloy

    Science.gov (United States)

    Jain, Rahul; Pal, Surjya Kanta; Singh, Shiv Brat

    2017-02-01

    Friction Stir Welding (FSW) is a solid state joining process and is handy for welding aluminum alloys. Finite Element Method (FEM) is an important tool to predict state variables of the process but numerical simulation of FSW is highly complex due to non-linear contact interactions between tool and work piece and interdependency of displacement and temperature. In the present work, a three dimensional coupled thermo-mechanical method based on Lagrangian implicit method is proposed to study the thermal history, strain distribution and thermo-mechanical process in butt welding of Aluminum alloy 2024 using DEFORM-3D software. Workpiece is defined as rigid-visco plastic material and sticking condition between tool and work piece is defined. Adaptive re-meshing is used to tackle high mesh distortion. Effect of tool rotational and welding speed on plastic strain is studied and insight is given on asymmetric nature of FSW process. Temperature distribution on the workpiece and tool is predicted and maximum temperature is found in workpiece top surface.

  14. Finite Element Simulation of Temperature and Strain Distribution during Friction Stir Welding of AA2024 Aluminum Alloy

    Science.gov (United States)

    Jain, Rahul; Pal, Surjya Kanta; Singh, Shiv Brat

    2016-06-01

    Friction Stir Welding (FSW) is a solid state joining process and is handy for welding aluminum alloys. Finite Element Method (FEM) is an important tool to predict state variables of the process but numerical simulation of FSW is highly complex due to non-linear contact interactions between tool and work piece and interdependency of displacement and temperature. In the present work, a three dimensional coupled thermo-mechanical method based on Lagrangian implicit method is proposed to study the thermal history, strain distribution and thermo-mechanical process in butt welding of Aluminum alloy 2024 using DEFORM-3D software. Workpiece is defined as rigid-visco plastic material and sticking condition between tool and work piece is defined. Adaptive re-meshing is used to tackle high mesh distortion. Effect of tool rotational and welding speed on plastic strain is studied and insight is given on asymmetric nature of FSW process. Temperature distribution on the workpiece and tool is predicted and maximum temperature is found in workpiece top surface.

  15. A Model for Evaluation of Grain Sizes of Aluminum Alloys with Grain Refinement Additions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the assumption that the nucleation substrates are activated by constitutional undercooling generated by an adjacent grain growth and solute distribution during the initial solidification, a model for calculation of the grain size of aluminum alloys with the grain refinement is developed, where the nucleation is dominated by two parameters, I.e. Growth restriction factor Q and the undercooling parameter P. The growth restriction factor Q is proportional to the initial rate of constitutional undercooling development and can be used directly as a criterion of the grain refinement in the alloys with strong potential nucleation particles. The undercooling parameter P can be regarded as the maximum of constitutional undercooling △TC. For weak potential nucleation particles, the use of RGS would be more accurate. The experimental data of the grain refinement of pure aluminum and AISi7 alloys are coincident predicted results with the model.

  16. Filtration of aluminum alloys and its influence on mechanical properties and shape of eutectical silicium

    Directory of Open Access Journals (Sweden)

    M. Brůna

    2008-07-01

    Full Text Available Filtration during casting of high quality aluminum alloys belongs to main refining methods. Even when there are many years of experiences and experimental works on this subject, there are still some specific anomalies. While using ceramic filtration media during casting of aluminum alloys, almost in all experiments occurred increase of strength limit and atypical increase of extension. This anomaly was not explained with classical metallurgical methods, black-white contrast after surface etching neither with color surface etching. For that reason was used deep etching on REM. By using pressed ceramic filters, by studying morphology eutectical silicon was observed modification morphology of eutectical silicon, this explains increase extension after filtration. Pressed ceramic filters were used on experimental works. Casting was executed on hardenable alloy AlSi10MgMn.

  17. Numerical simulation of deep cryogenic treatment electrode tip temperature for spot welding aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Wu Zhisheng; Hu Minying; Liu Cuirong

    2006-01-01

    Deep cryogenic treatment technology of electrodes is put forward to improve electrode life of resistance spot welding of aluminum alloy LF2. Deep cryogenic treatment makes electrode life for spot welding aluminum alloy improve. The specific resistivity of the deep cryogenic treatment electrodes is tested and experimental results show that specific resistivity is decreased sharply. The temperature field and the influence of deep cryogenic treatment on the electrode tip temperature during spot welding aluminium alloy is studied by numerical simulation method with the software ANSYS. The axisymmetric finite element model of mechanical, thermal and electrical coupled analysis of spot welding process is developed. The numerical simulation results show that the influence of deep cryogenic treatment on electrode tip temperature is very large.

  18. Effect of Electromagnetic Treatment on Fatigue Resistance of 2011 Aluminum Alloy

    Science.gov (United States)

    Mohin, M. A.; Toofany, H.; Babutskyi, A.; Lewis, A.; Xu, Y. G.

    2016-08-01

    Beneficial effects of the electromagnetic treatment on fatigue resistance were reported on several engineering alloys. These could be linked to the dislocation activity and the rearrangement of the crystal structure of the material under the electromagnetic field (EMF), resulting in delayed crack initiation. This paper presents an experimental study on the effect of pulsed electromagnetic treatment on the fatigue resistance of 2011 aluminum alloy. Circular cantilever specimens with loads at their ends were tested on rotating fatigue machine SM1090. Fatigue lives of treated and untreated specimens were analyzed and compared systematically. It has been found that the effect of the pulsed electromagnetic treatment on the fatigue resistance is dependent on the intensity of the pulsed EMF and the number of the treatment applied. Clear beneficial effect of the pulsed electromagnetic treatment on the fatigue resistance of the aluminum alloys has been observed, demonstrating a potential new technique to industries for fatigue life extension.

  19. Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2015-12-31

    The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

  20. The Mechanical Behavior of Friction-Stir Spot Welded Aluminum Alloys

    Science.gov (United States)

    Güler, Hande

    2014-10-01

    Aluminum and alloys are widely used in the automotive industry due to the light weight, good formability, and malleability. Spot welding is the most commonly used joining method of these materials, but the high current requirements and the inconsistent quality of the final welds make this process unsuitable. An alternative welding technique, the friction-stir spot welding process, can also be successfully used in joining of aluminum and alloys. In this study, 1-mm-thick AA5754 Al-alloy plates in the H-111 temper conditions were joined by friction-stir spot welding using two different weld parameters such as tool rotational speed and dwell time. Mechanical properties of the joints were obtained with extensive hardness measurements and tensile shear tests. The effect of these parameters on the failure modes of welded joints was also determined.

  1. Preparation and characterization of electroplated amorphous gold-nickel alloy film for electrical contact applications

    Energy Technology Data Exchange (ETDEWEB)

    Togasaki, Norihiro [Department of Applied Chemistry, Waseda University, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Okinaka, Yutaka [Advanced Research Institute for Science and Engineering, Waseda University, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Homma, Takayuki [Department of Applied Chemistry, Waseda University, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Advanced Research Institute for Science and Engineering, Waseda University, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Osaka, Tetsuya [Department of Applied Chemistry, Waseda University, Okubo, Shinjuku, Tokyo 169-8555, Japan and Advanced Research Institute for Science and Engineering, Waseda University, Okubo, Shinjuku, Tokyo 169-8555 (Japan)]. E-mail: osakatet@waseda.jp

    2005-11-10

    A process for electroplating amorphous gold-nickel alloy with the atomic ratio of unity was developed. The plating bath was prepared by adding potassium cyanoaurate(I) into a known plating bath which produces amorphous nickel-tungsten alloy. At a sufficiently high gold concentration, the alloy deposit did not contain any tungsten. The amorphous nature of the Au-Ni alloy produced in the new bath was confirmed by using TEM and THEED. Hardness, resistivity, and contact resistance of this new alloy were determined, and the results are discussed for applications as an electrical contact material.

  2. Research for the method of image acquisition of the molten pool in the TIG welding of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    王建军; 林涛; 陈善本; 王伟

    2004-01-01

    Obtaining the image of molten pool aluminum alloy's tungsten inert gas(TIG)welding becomes a challenging problem in the welding field. In this paper, a bran-new optical sensor based analyzing the light spectrum was designed, and the clear image of the molten pool during the aluminum alloy's welding using the common industrial CCD camera was obtained. And with the new algorithm provided by myself, the desirable characteristic parameters of the molten pool of aluminum alloy's welding were obtained, and it provides a good base for advanced monitor welding quality.

  3. Properties of splat-quenched 7075 aluminum type alloys

    Science.gov (United States)

    Durand, J. P. H. A.; Pelloux, R. M.; Grant, N. J.

    1976-01-01

    The 7075 alloy belonging to the Al-Zn-Mg-Cu system, prepared by powder metallurgy techniques, was used in a study of alloys prepared from splat-quenched foils consolidated into bar material by hot extrusion. Ni and Fe were included in one alloy specimen, producing a fine dispersion of FeAl3 type particles which added to the strength of the aged alloy but did not coarsen upon heat treatment. Fine oxide films showing up on air-splatted foils induce finely dispersed oxide stringers (if the foils are not hot-worked subsequently) which in turn promote axial cracking (but longitudinal tensile strength is not seriously impaired). Splatting in a protective atmosphere, or thermomechanical processing, is recommended to compensate for this.

  4. Thermal compatibility studies of unirradiated UMo alloys dispersed in aluminum

    Science.gov (United States)

    Lee, Don Bae; Kim, Ki Hwan; Kim, Chang Kyu

    1997-11-01

    The thermal compatibility of centrifugally atomized UMo alloys with aluminium has been studied. The results of the investigations show that the U-2 wt% Mo/aluminum dispersions increase in volume by 26% at 400°C after 2000 h. This large volume change is mainly due to the formation of voids and cracks resulting from nearly complete interdiffusion of UMo and aluminum. No significant dimensional changes occur in the U-10 wt% Mo/aluminum dispersions. Interdiffusion between U-10 wt% Mo and aluminum is found to be minimal. The different diffusion behavior is primarily due to the fact that U-10 wt% Mo particles are much more supersaturated with substitutional molybdenum than U-2 wt% Mo particles. The aluminum diffuses into the U-2 wt% Mo particles relatively rapidly along grain boundary with nearly pure uranium, forming UAl 3 almost fully throughout the 2000 h anneal, whereas the molybdenum supersaturated in the U-10 wt% Mo particles inhibits the diffusion of aluminum atoms. U-10 wt% Mo displays superior thermal compatibility with aluminum compared to U-2 wt% Mo.

  5. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

    Science.gov (United States)

    Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

    2016-11-05

    Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

  6. Study of corrosion protection of the composite fdms on A356 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    SUN Huanhuan; WANG Hui; MENG Fanling

    2011-01-01

    Composite films were fabricated on A356 aluminum alloy by combined anodizing and rare earth deposition.The corrosion protection effect and corrosion behavior of the composite films in 3.5% NaC1 solution were studied by electrochemical impedance spectroscopy (EIS).SEM observation indicated that the rare earth Ce film completely sealed the porous structure of the anodic film,and the composite films composed of anodic film and Ce film were compact and integrated.According to the characteristics of EIS,the EIS plots of the composite films at different immersion times were simulated using the equivalent circuits of Rsol(QceRce)(QaRa),Rsol(QceRce)(QpRp)(QbRb) and Rsol(QpRp)(QbRb) models,respectively.The test results showed that the Ce film at the outer layer of the composite films had good protection effect at the initial stage of the immersion corrosion.It effectively helped the anodie film at the inner layer to prevent chloride irons from penetrating the aluminum alloy matrix.After 18 days,the Ce film lost its anticorrosive property,and the anodic film took the leading role of the corrosion protection.When the corrosion time was up to 42 days,the aluminum matrix was not corroded yet.Thus,the higher protection degree of the composite films for A356 aluminum alloy was attributed to the synergism effects of anodic film and rare earth Ce film.

  7. Effect of wire EDM conditions on generation of residual stresses in machining of aluminum 2014 T6 alloy

    Directory of Open Access Journals (Sweden)

    Pujari Srinivasa Rao

    2016-06-01

    Full Text Available Wire electrical discharge machining (EDM possesses many advantages over the conventional manufacturing process. Hence, this process was used for machining of all conductive materials; especially, nowadays this is the most common process for machining of aerospace aluminum alloys. This process produces complex shapes in aluminum alloys with extremely tight tolerances in a single setup. But, for good surface integrity and longer service life, the residual stresses generated on the components should be as low as possible and it depends on the setting of process parameters and the material to be machined. In wire EDM, much of the work was concentrated on Titanium alloys, Inconel alloys and various types of steels and partly on aluminum alloys. The present investigation was a parametric analysis of wire EDM parameters on residual stresses in the machining of aluminum alloy using Taguchi method. The results obtained had shown a wide range of residual stresses from 8.2 to 405.6 MPa. It also influenced the formation of various intermetallics such as AlCu and AlCu3. Microscopic examination revealed absence of surface cracks on aluminum surface at all the machining conditions. Here, an attempt was made to compare the results of aluminum alloy with the available machined data for other metals.

  8. On Residual Stresses in Resistance Spot-Welded Aluminum Alloy 6061-T6: Experimental and Numerical Analysis

    Science.gov (United States)

    Afshari, D.; Sedighi, M.; Karimi, M. R.; Barsoum, Z.

    2013-12-01

    In this study, an electro-thermal-structural-coupled finite element (FE) model and x-ray diffraction residual stress measurements have been utilized to analyze distribution of residual stresses in an aluminum alloy 6061-T6 resistance spot-welded joint with 2-mm-thickness sheet. Increasing the aluminum sheet thickness to more than 1 mm leads to creating difficulty in spot-welding process and increases the complexity of the FE model. The electrical and thermal contact conductances, as mandatory factors are applied in contact areas of electrode-workpiece and workpiece-workpiece to resolve the complexity of the FE model. The physical and mechanical properties of the material are defined as thermal dependent to improve the accuracy of the model. Furthermore, the electrodes are removed after the holding cycle using the birth-and-death elements method. The results have a good agreement with experimental data obtained from x-ray diffraction residual stress measurements. However, the highest internal tensile residual stress occurs in the center of the nugget zone and decreases toward nugget edge; surface residual stress increases toward the edge of the welding zone and afterward, the area decreases slightly.

  9. Microstructures of erbium modified aluminum-copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berghof-Hasselbaecher, Ellen; Schmidt, Gerald; Galetz, Mathias; Schuetze, Michael [DECHEMA-Forschungsinstitut, Frankfurt am Main (Germany); Masset, Patrick J. [Fraunhofer UMSICHT-ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany); Zhang, Ligang [Technische Univ. Bergakademie Freiberg (Germany). ZIK Virtuhcon; Liu, Libin; Jin, Zhanpeng [Central South Univ., Changsha, Hunan (China)

    2012-07-01

    Alloying with rare earth metals improves to the mechanical properties and corrosion resistance of aluminium base alloys at high temperatures. The rare earth metal erbium may be used for grain refinement. Within a project of computer-aided alloy development based on the CALPHAD (CALculation of PHAse Diagrams) method various alloys were melted on the Al-rich side of the ternary system Al-Cu-Er under argon atmosphere and their microstructures were characterized in the as-cast state or after long-term isothermal annealing (400 C/960 h) by means of different investigation techniques. As a result, the phases fcc (Al), {tau}{sub 1}-Al{sub 8}Cu{sub 4}Er, {theta}-CuAl{sub 2}, {eta}-CuAl, and Al{sub 3}Er were identified, their compositions and fractions were quantified, and their hardnesses were determined. The experimental obtained microstructures agree very well with the calculated solidification behaviors of the cast alloys. The knowledge gained from this work about the phase compositions and microstructures can also be utilized for the fine optimization of the phase diagram. (orig.)

  10. Some organic compounds as inhibitors for the corrosion of aluminum alloy 6063 in deaerated carbonate solution

    Energy Technology Data Exchange (ETDEWEB)

    Bazzi, L.; Hamdani, M. [Lab. de Chimie Physique, Agadir (Morocco); Kertit, S. [Ecole Normale Superieure de Takaddoum, Rabat (Morocco). Lab. de Physico-Chimie des Materiaux

    1995-11-01

    Some organic compounds were tested as corrosion inhibitors for aluminum alloy 6063 (Al 6063, UNS A96063) in a deaerated carbonate solution using the electrochemical polarization method. The compounds studied were thiourea (TOR), diorthoaminodiphenyldisulfane (DOAPD), and benzotriazole (BTA). Results showed DOAPD was the best inhibitor. Its inhibition efficiency reaches a maximum value of 95.8% at 10{sup {minus}2} M. Polarization measurements indicated DOAPD acted as a cathodic and anodic (mixed) inhibitor without changing the mechanism of the water evolution reaction. DOAPD was adsorbed on the aluminum surface according to a Langmuir isotherm model. The other compounds tested had no effect on pitting corrosion of Al 6063.

  11. Novel algorithm for determining optimal blankholder forces in deep drawing of aluminum alloy sheet

    Institute of Scientific and Technical Information of China (English)

    孙成智; 陈关龙; 林忠钦; 赵亦希

    2004-01-01

    Wrinkling and fracture are main defects in sheet metal forming of aluminum alloy sheet, which can be reduced or even eliminated by manipulating a suitable blank-holder forces (BHF). But, it is difficult to attain the optimum BHF during sheet metal forming. A new optimization algorithm integrating the finite element method (FEM)and adaptive response surface method is presented to determinate the optimal BHFs in deep drawing of aluminum rectangular box. To assure convergence, the trust region modes management strategies are used to adjust the move limit of design spaces. Finally, the optimum results of rectangular box deep drawing are given. Verification experiments are performed to verify the optimal result.

  12. Continuous Severe Plastic Deformation Processing of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan Srinivasan (PI); Prabir K. Chaudhury; Balakrishna Cherukuri; Qingyou Han; David Swenson; Percy Gros

    2006-06-30

    by SPD techniques. This combination of properties makes UFG metals produced by SPD very attractive as machining, forging or extrusion stock, both from the point of view of formability as well as energy and cost saving. However, prior to this work there had been no attempt to transfer these potential benefits observed in the laboratory scale to industrial shop floor. The primary reason for this was that the laboratory scale studies had been conducted to develop a scientific understanding of the processes that result in grain refinement during SPD. Samples that had been prepared in the laboratory scale were typically only about 10-mm diameter and 50-mm long (about 0.5-inch diameter and 2-inches long). The thrust of this project was three-fold: (i) to show that the ECAE/P process can be scaled up to produce long samples, i.e., a continuous severe plastic deformation (CSPD) process, (ii) show the process can be scaled up to produce large cross section samples that could be used as forging stock, and (iii) use the large cross-section samples to produce industrial size forgings and demonstrate the potential energy and cost savings that can be realized if SPD processed stock is adopted by the forging industry. Aluminum alloy AA-6061 was chosen to demonstrate the feasibility of the approach used. The CSPD process developed using the principles of chamber-less extrusion and drawing, and was demonstrated using rolling and wire drawing equipment that was available at Oak Ridge National Laboratory. In a parallel effort, ECAE/P dies were developed for producing 100-mm square cross section SPD billets for subsequent forging. This work was carried out at Intercontinental Manufacturing Co. (IMCO), Garland TX. Forging studies conducted with the ECAE/P billets showed that many of the potential benefits of using UFG material can be realized. In particular, the material yield can be increased, and the amount of material that is lost as scrap can be reduced by as much as 50%. Forging

  13. Continuous Severe Plastic Deformation Processing of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan Srinivasan (PI); Prabir K. Chaudhury; Balakrishna Cherukuri; Qingyou Han; David Swenson; Percy Gros

    2006-06-30

    by SPD techniques. This combination of properties makes UFG metals produced by SPD very attractive as machining, forging or extrusion stock, both from the point of view of formability as well as energy and cost saving. However, prior to this work there had been no attempt to transfer these potential benefits observed in the laboratory scale to industrial shop floor. The primary reason for this was that the laboratory scale studies had been conducted to develop a scientific understanding of the processes that result in grain refinement during SPD. Samples that had been prepared in the laboratory scale were typically only about 10-mm diameter and 50-mm long (about 0.5-inch diameter and 2-inches long). The thrust of this project was three-fold: (i) to show that the ECAE/P process can be scaled up to produce long samples, i.e., a continuous severe plastic deformation (CSPD) process, (ii) show the process can be scaled up to produce large cross section samples that could be used as forging stock, and (iii) use the large cross-section samples to produce industrial size forgings and demonstrate the potential energy and cost savings that can be realized if SPD processed stock is adopted by the forging industry. Aluminum alloy AA-6061 was chosen to demonstrate the feasibility of the approach used. The CSPD process developed using the principles of chamber-less extrusion and drawing, and was demonstrated using rolling and wire drawing equipment that was available at Oak Ridge National Laboratory. In a parallel effort, ECAE/P dies were developed for producing 100-mm square cross section SPD billets for subsequent forging. This work was carried out at Intercontinental Manufacturing Co. (IMCO), Garland TX. Forging studies conducted with the ECAE/P billets showed that many of the potential benefits of using UFG material can be realized. In particular, the material yield can be increased, and the amount of material that is lost as scrap can be reduced by as much as 50%. Forging

  14. Interactive effect of cerium and aluminum on the ignition point and the oxidation resistance of magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lin Pengyu [Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun Jilin 130025 (China)], E-mail: linpengyu2000@yahoo.com.cn; Zhou Hong; Li Wei; Li Wenping; Sun Na [Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Nanling Campus of Jilin University, Changchun Jilin 130025 (China); Yang Rong [Public Mathematics Teaching and Research Center, College of Mathematics, Qianwei Campus of Jilin University, Changchun Jilin 130012 (China)

    2008-09-15

    This paper focused on the interactive effect of cerium (Ce) addition and aluminum (Al) content in magnesium alloy on ignition point and oxidation resistance. Ce content played an important role in improving the oxidation resistance of Mg alloy. Ignition point ascended with increasing Ce content. 0.25 wt% Ce content in Mg alloys could greatly improve tightness of the oxide film of Mg alloys. However, when Ce content in the alloy exceeded its solid solubility, ignition point descended. Furthermore, Al content in the alloy also influenced the ignition point. The higher the Al content was, the lower the ignition point.

  15. Corrosion of LY12 aluminum alloy in sodium chloride solution

    Institute of Scientific and Technical Information of China (English)

    程英亮; 张昭; 曹发和; 李劲风; 张鉴清; 王建明; 曹楚南

    2003-01-01

    The corrosion behavior of LY12 alloy in sodium chloride solution and its electrochemical noise were reported. The development of the micro-pits on the alloy surface was monitored by scanning electron microscopy, scanning tunneling microscopy, and electrochemical noise method. All the measurements show that the corrosion of LY12 alloy can be divided into two stages: a very reactive initial stage and a relative constant stable stage. The initial stage is corresponded to the adsorption of Cl ions and its reaction with the oxide film and the dissolution of Mg containing particles. The stable stage is corresponded to the development of the micro-pits by the galvanic attack formed by Al-Fe-Cu-Mn containing particles and the matrix. The initial stage lasts about 2-3 h while the stable stage dominates the whole corrosion process.

  16. Effects of electromagnetic stirring on microstructures of solidified aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    时海芳; 张伟强

    2003-01-01

    Al-20%Cu, Al-33%Cu and Al-7%Si alloys were solidified with electromagnetic stirring(EMS). The fluid flow induced by electromagnetic stirring leads to the increases of the lamellar spacing of Al-CuAl2 and Al-Si eutectics and the secondary dendritic arm spacing. Rod-like eutectic structure plus pro-eutectic α(Al) are observed in Al-Cu eutectic alloy when the agitating voltage is increased over 130 V, and in the hypoeutectic alloys, globular grains of proeutectic α(Al) grains may form when the magnetic field is strong enough. The Si flakes in the Al-Si eutectic are also coarsened by applying forced flow during solidification, which is always related to the depression of their branching in the growth by the forced convection.

  17. Effect of age condition on fatigue properties of 2E12 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Liang; DU Feng-shan; DAI Sheng-long; YANG Shou-jie

    2010-01-01

    The fatigue behaviors of 2E12 aluminum alloy in T3 and T6 conditions at room temperature in air were investigated.The microstructures and fatigue fracture surfaces of the alloy were examined by transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The results show that the alloy exhibits higher fatigue crack propagation(FCP)resistance in T3condition than in T6 condition,the fatigue life is increased by 54% and the fatigue crack growth rate(FCGR)decreases significantly.The fatigue fractures of the alloy in T3 and T6 conditions are transgranular.But in T3 condition,secondary cracks occur and fatigue striations are not clear.In T6 condition,ductile fatigue striations are observed.The effect of aging conditions on fatigue behaviors is explained in terms of the slip planarity of dislocations and the cyclic slip reversibility.

  18. Fundamental Studies on the Aluminum-Lithium-Beryllium Alloy System.

    Science.gov (United States)

    1986-08-01

    Rapidly Solidified Crystalline Alloys ," S.K... Solidified Crystalline Alloys ," S.K. Das, B.H. Kear, and C.M. Adam, eds., pp. 157-183, The ,W Metallurgical Society of AIME, Warrendale, PA, (1986). 2.i...Adda, J. Phys. 29, 345(1968) °t. 8. W.C. Oliver and W.D. Nix, Acta Metall. vol. 30,pp. 1335 to - 1347(1982). 9. C.M. Adam and R.E. Lewis, " Rapidly

  19. Effect of Surface Pretreatment on Adhesive Properties of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Jinsheng ZHANG; Xuhui ZHAO; Yu ZUO; Jinping XIONG; Xiaofeng ZHANG

    2008-01-01

    The lap-shear strength and durability of adhesive bonded AI alloy joints with different pretreatments were studied by the lap-shear test and wedge test. The results indicate that the maximum lap-shear strength and durability of the bonding joints pretreated by different processes are influenced by the grade of abrasive papers and can be obviously improved by phosphoric acid anodizing. Alkali etching can obviously improve the durability of bonding joints although it slightly influences the maximum lap-shear strength. The process which is composed of grit-finishing, acetone degreasing, alkali etching and phosphoric acid anodizing, provides a better adhesive bonding property of AI alloy.

  20. Technical parameters in electromagnetic continuous casting of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    李玉梅; 张兴国; 贾非; 姚山; 金俊泽

    2003-01-01

    The temperature field of aluminum ingot during electromagnetic continuous casting was calculated by the numerical method, and the effects of cooling water strength, position of the cooling water holes and pouring temperature as well as induction heat on casting speed, were studied. The results show that among the technical parameters the distance from the position of the cooling water holes to the bottom of the mold is the most important factor, whose change from 20mm to 15mm and from 15mm to 10mm causes the setting rate increasing respectively by 0.14mm/s and 0.3mm/s.The calculated results also agree with the experiment well. The simulation program can be used to determine technical parameters of electromagnetic casting of aluminum ingot effectively.

  1. Design and Processing of Bimetallic Aluminum Alloys by Sequential Casting Technique

    Science.gov (United States)

    Karun, Akhil S.; Hari, S.; Ebhota, Williams S.; Rajan, T. P. D.; Pillai, U. T. S.; Pai, B. C.

    2017-01-01

    Sequential casting is a facile and fairly new technique to produce functionally graded materials (FGMs) and components by controlled mold filling process. In the present investigation, functionally graded bimetallic aluminum alloys are produced by sequential gravity casting using A390-A319 and A390-A6061 alloy combinations. The control in pouring time between two melts has shown a significant effect on the quality and nature of interface bonding. The microstructure reveals good interface miscibility achieved through diffusion bonding between the alloys. A higher hardness of 160 BHN in the A390 region is obtained in both sequential cast systems, and a minimum value of 105 and 91 BHN is observed in the A319 and A6061 regions, respectively. The tensile and compression strength for A390-A319 are 337 and 490 MPa, whereas for A390-A6061, they are 364 and 401 MPa, respectively, which are significantly higher compared with the standard values of the base alloys, which confirms strong interface bonding. The A390 region shows higher wear resistance compared with other regions of the sequential cast system. The process described in this study is a potential and efficient approach to create good bonding between two different aluminum alloys to develop advanced functional and structural materials.

  2. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    Science.gov (United States)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-07-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  3. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  4. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft

    Science.gov (United States)

    Starke, E. A., Jr. (Editor)

    1995-01-01

    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  5. Characterization and Tribological Properties of Hard Anodized and Micro Arc Oxidized 5754 Quality Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    M. Ovundur

    2015-03-01

    Full Text Available This study was initiated to compare the tribological performances of a 5754 quality aluminum alloy after hard anodic oxidation and micro arc oxidation processes. The structural analyses of the coatings were performed using XRD and SEM techniques. The hardness of the coatings was determined using a Vickers micro-indentation tester. Tribological performances of the hard anodized and micro arc oxidized samples were compared on a reciprocating wear tester under dry sliding conditions. The dry sliding wear tests showed that the wear resistance of the oxide coating generated by micro arc oxidation is remarkably higher than that of the hard anodized alloy.

  6. Fatigue Induced Alteration of the Superficial Strength Properties of 2024 Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    K.-D. Bouzakis; I. Mirisidis; Sp. G. Pantelakis; A.N. Chamos

    2011-01-01

    aluminum alloy 2024 T3 specimens have been subjected to constant amplitude fatigue loading at R=0.1. During fatigue, an appreciable increase of the surface hardness of the material at the meso-scale can be observed and captured by means of nanoindentations. Surface hardness increases with increasing fatigue stress amplitude and advancing number of applied fatigue cycles. Observed increase of specimen surface hardening degree during fatigue causes an evolution of superficial mechanical strength properties of the alloy. Stress-strain curves associated with the evoluting superficial mechanical properties are derived, employing a developed finite element method (FEM)-supported evaluation procedure of nanoindentation experimental results.

  7. Part A - low-aluminum-content iron-aluminum alloys. Part B - commercial-scale melting and processing of FAPY alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Howell, C.R.; Hall, F.; Valykeo, J. [Hoskins Manufacturing Co., Hamburg, MI (United States)

    1996-06-01

    The FAPY is a Fe-16 at. % Al alloy of nominal composition. The aluminum content of the alloy is such that it remains single phase ({alpha}) without the formation of an ordered phase (DO{sub 3}). The alloy has good oxidation resistance at temperatures up to 1000{degrees}C and has shown significantly superior performance as heating elements as compared to the commonly used nickel-based alloy, Nichrome. Although wire for the heating elements has been fabricated from small (15-1b) laboratory heats, for its commercial applications, the wire needs to be producible from large (1200 to 1500-1b) air-melted heats. The purpose of this study was to produce commercial size heats and investigate their mechanical properties and microstructure in the as-cast, hot-worked, and cold-worked conditions. The results of this study are expected to provide: (1) insight into processing steps for large heats into wire under commercial conditions, and (2) the mechanical properties data on commercial size heats in various product forms.

  8. FEM Analysis of Spring-backs in Age Forming of Aluminum Alloy Plates

    Institute of Scientific and Technical Information of China (English)

    Huang Lin; Wan Min; Chi Cailou; Ji Xiusheng

    2007-01-01

    The age forming technology, characterized by huge spring-backs, has been developed to manufacture large integral wing-skin panel parts, which necessitates devising a method of predicting spring-backs. A 7B04-T7451 aluminum alloy creep test in tension is accomplished at 155 ℃, and the creep curves are obtained. The material constants of the mechanism-based creep constitutive equations are determined through experiments. The age forming process and the spring-backs of 7B04 aluminum alloy plates are analyzed using the commercial finite element software ABAQUS. The effects of plate thickness and formingtime on spring-backs are researched. The spring-backs decrease with the increase of plate thickness and forming time. The test results verify the reliability of the finite element method (FEM) analysis.

  9. 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.

  10. Preparation of Scandium-Bearing Master Alloys by Aluminum-Magnesium Thermoreduction

    Institute of Scientific and Technical Information of China (English)

    姜锋; 白兰; 尹志民

    2002-01-01

    The new preparation method of scandium-bearing master alloys, in which scandium oxide was fluorinated by reaction with NH4HF2 and then reduced by aluminum-magnesium in fused salt containing alkali and alkaline fluoride under atmosphere, was studied. The effect of sorts of metallic reductive and technique conditions such as reducing temperature and time on the recovery of Sc was discussed. When the liquid aluminum-magnesium was used as the reductive agent, the all-recovery exceeds 80% and the concentration of Sc in master alloy prepared exceeds 1.9%. The best reducing reaction temperature and time are 1100 K and 40 min respectively. The newly produced Sc from reduction combines with Al to produce the stable compound Al3Sc, so the reduction progress is sustained and the recovery of Sc is increased.

  11. Finite element analysis of free expansion of aluminum alloy tube under magnetic pressure

    Institute of Scientific and Technical Information of China (English)

    YU Hai-ping; LI Chun-feng

    2005-01-01

    A link between the electromagnetic code, ANSYS/Emag and the structural code, Ls-dyna was developed, and the numerical modeling of electromagnetic forming for aluminum alloy tube expansion was performed by means of them (discharge energy 0.75 kJ). A realistic distribution of magnetic pressure was calculated. The calculated values of displacement along the tube axis and versus time are in very good agreement with the measured ones.The maximum strain rate is 1 122 s-1, which is not large enough to change the constitutive equations of aluminum alloy. With the augment of discharge energy (0. 5 - 1.0 kJ), the relative errors of the maximum deformation increase from 2.93% to 11.4%. Therefore, coupled numerical modeling of the electromagnetic field and the structural field should be performed to investigate the electromagnetic forming with larger deformation.

  12. The intermetallic bonding between a ring carrier and aluminum piston alloy

    Energy Technology Data Exchange (ETDEWEB)

    Manasijevie, S.; Dolie, N.; Djurdjevic, M.; Misic, N.; Davitkov, N.

    2015-07-01

    This paper presents the results of investigating the formation of intermetallic bond between a ring carrier and aluminum piston alloy. The ring carrier is made of austenitic cast iron (Ni-Resist) in order to increase the wear resistance of the first ring groove and applied in highly loaded diesel engines. Metallographic examination of the quality of al fin bond was done. A metallographic investigation using an optical microscope in combination with the SEM/EDS analysis of the quality of the intermetallic bonding layer was done. The test results show that can be made successfully as well as the formation of metal connection (alfin bond) between the ring carrier and aluminum piston alloy. (Author)

  13. Evaluation of residual stress relief of aluminum alloy 7050 by using crack compliance method

    Institute of Scientific and Technical Information of China (English)

    王秋成; 柯映林; 邢鸿燕; 翁泽宇; 杨芳儿

    2003-01-01

    High strength aluminum alloys of 7xxx series have unacceptable levels of quenching residual stresses from solution heat treatment. The residual stress not only results in machining distortion and dimensional instability, but also increases the possibility of stress corrosion cracks. Therefore, it is necessary to reduce the residual stress to an acceptable level. The crack compliance method was adopted to study the influences of various stress relief methods on residual stress patterns in 7050 aluminum alloy. The results show that 90% residual stress can be eliminated by the cold stretching(Tx51) method. And a lower level of residual stress can be achieved by the uphill quenching(Tx53) method or the cold compression(Tx52). However, there is a very steep residual stress gradient normal to exterior surfaces.

  14. Numerical simulation on bucking distortion of aluminum alloy thin-plate weldment

    Institute of Scientific and Technical Information of China (English)

    Jun LI; Jian-guo YANG; Ha-Mong LI; De-jun YAN; Hong-yuan FANG

    2009-01-01

    In this paper, the welding residual distortion of aluminum alloy thin plates is predicted using the elasticity-plasticity finite element method (FEM). The factors contributing to the welding buckling distortion of thin plates are studied by investigating the formation and evolution process of welding stresses. Results of experi-ments and numerical simulations show that the buckling appearance of thin-plate aluminum alloy weldments is asymmetrical in the welding length direction, and the maximum longitudinal deflection appears at the position a certain distance from the middle point of the side edge towards the arc-starting end. The angular deformation direction of thin-plate weldments is not fixed, and such case as the angular deformation value of the arc-starting end being higher than that of the arc-blowout end exists.

  15. Electrochemical Impedance Study of Zinc Yellow Polypropylene-Coated Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Zhi-hua Sun

    2010-01-01

    Full Text Available Performance of zinc yellow polypropylene-coated aluminum alloy 7B04 during accelerated degradation test is studied using electrochemical impedance spectroscopy (EIS. It has been found that the zinc yellow polypropylene paint has few flaw and acts as a pure capacitance before accelerated test. After 336-hour exposure to the test, the impedance spectroscopy shows two time constants, and water has reached to the aluminum alloy/paint interface and forms corrosive microcell. For the scratched samples, the reaction of metal corrosion and the hydrolysis of zinc yellow ion can occur simultaneously. The impedance spectroscopy indicates inductance after 1008-hour exposure to the test, but the inductance disappears after 1344-hour exposure and the passivation film has pitting corrosion.

  16. Flow stress equation for multipass hot-rolling of aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of simple axisymmetric compression tests were carried out on the computer servo-controlled Gleeble 1 500 machine when strain rates ranged between 0.05-25 s-1 and deformation temperature 300-500 ℃. The results show that flow stress is related to the Zener-Hollonom parameter Z and strain, as well as the static recrystallization fraction between passes during multipass hot deformation of 5182 aluminum alloy. Hence, a modified exponential flow stress equation was presented by considering the values of lnA and β as functions of strain, and by using the uniform softening method and incorporating the static recrystallization fraction between passes to consider the effects of residual strain during multipass hot-rolling of 5182 aluminum alloy. The validity of the equation was examined by a typical non-isothermal multipass deformation test.

  17. Effect of Intermediate Annealing on Microstructure and Property of 5182 Aluminum Alloy Sheet for Automobile

    Directory of Open Access Journals (Sweden)

    WANG Yu

    2016-09-01

    Full Text Available Effect of intermediate annealing on the microstructure and properties of 5182 aluminum alloy sheet with full annealed state (5182-O was investigated by means of optical microscope, scanning electron microscope and universal testing machine. The results indicate that compared with 5182-O sheet without intermediate annealing, 5182-O sheet with intermediate annealing possesses too fine grain size, intermetallic compounds not broken enough, larger size intermetallic particles, less dispersed phase. Yield strength and ultimate tensile strength, work hardening exponent and normal anisotropy of plastic strain ratio decrease but planner anisotropy of plastic strain ratio increases. The mechanical properties and forming ability of 5182-O aluminum alloy sheet and its microstructure are not improved significantly after intermediate annealing.

  18. Moiré method analysis for tensile strain field of 2024 aluminum alloy welded joint

    Institute of Scientific and Technical Information of China (English)

    徐文立; 魏艳红; 刘雪松; 方洪渊; 赵敏; 田锡唐

    2003-01-01

    Using experimental mechanics method of moiré analysis, strain field distributions of 2024 aluminum alloy welded joints under different conditions were investigated. The results show that moiré stripes of welded joint without trailing peening just before fracture are not only few and scattered but also uneven, and the stress mainly concentrates on the poor position-welded toes during the tensioning process with the relatively poor mechanical properties of welded joints; When the method of welding with trailing peening is adopted, moiré stripes of welded joint just before fracture are relatively thick and even due to the strengthening welded toes during the welding process, and fracture position transfers from the welded toes to weld, at the same time the mechanical properties of welded joints are improved greatly than conventional welding which can show that the technology of trailing peening is effective to strengthen welded joints of aluminum alloy with high strength.

  19. Specific Energy Absorbed Study Of Aluminum (2024-351T Tubes Alloy Under Lateral Crush

    Directory of Open Access Journals (Sweden)

    Ayad Arab Ghaidan

    2013-04-01

    Full Text Available This paper aims to find SEA (Specific Energy Absorber for lateral crushing (statically behavior for Aluminum (2024-T351 alloy with difference lengths (10, 20, and 30 mm. An experimental, finite element simulation, and theoretical models present to find force-deformation curves and then find SEA for difference lengths. Experimental results more agreements with finite elements simulation and theoretical when length of tubes is increase for load deformation curve, because when the length increases the plastic region increase with initial plastic collapse load (Pc. The experimental, ANSYS simulation and theoretical results have plotted and it has seen that the theory also underestimates the ANSYS results because in theoretical model, is customary to assume that the material is perfectly plastic, therefore, the finite element simulation might predict the experimental results better than the theoretical one. The results show that light density Aluminum alloy is suitable for SEA.

  20. Effect of extrusion temperature on the physical properties of high-silicon aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    YANG Fuliang; GAN Weiping; CHEN Zhaoke

    2007-01-01

    Light-weight high-silicon aluminum alloys are used for electronic packaging in the aviation and space- flight industry. Al-30Si and Al-40Si are fabricated with air- atomization and vacuum-canning hot-extrusion process. The density, thermal conductivity, hermeticity and thermal expan- sion coefficients of the material are measured, and the relationship between extrusion temperature and properties is obtained. Experimental results show that the density of high- silicon aluminum alloys prepared with this method is as high as 99.64% of the theory density, and increases with elevating extrusion temperature. At the same time, thermal conductiv- ity varies between 104-140W/(m.K); with the extrusion temperature, thermal expansion coefficient also increases but within 13 × 10-6 (at 100℃) and hermeticity of the material is high to 10-9 order of magnitude.

  1. The Effect of Creep Aging on the Fatigue Fracture Behavior of 2524 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Wenke Li

    2016-09-01

    Full Text Available Normal temperature tensile and fatigue tests were adopted to test the mechanical performance and fatigue life of 2524 aluminum alloy under the three states of T3, artificial aging, and creep aging, and scanning electron microscope and transmission electron microscope were also used to observe the fatigue fracture morphology and aging precipitation features of the alloy under the above three states. Results showed that the alloy treated by creep aging can obtain higher fatigue life, but that treated by artificial aging is lower than T3; T3 alloy is mainly dominated by GPB region. Meanwhile, the crystal boundary displays continuously distributed fine precipitated phases; after artificial aging and creep aging treatment, a large amount of needle-shaped S′ phases precipitate inside the alloy, while there are wide precipitated phases at the crystal boundary. Wide precipitation free zones appear at the crystal boundary of artificial-aging samples, but precipitation free zones at the alloy crystal boundary of creep aging become narrower and even disappear. It can be seen that creep aging can change the precipitation features of the alloy and improve its fatigue life.

  2. Effect of Fe on Microstructure and Properties of 8xxx Aluminum Conductor Alloys

    Science.gov (United States)

    Pan, Lei; Liu, Kun; Breton, Francis; -Grant Chen, X.

    2016-12-01

    The effect of Fe contents (0.3-0.7 wt.%) on the microstructure, electrical conductivity, mechanical and creep properties of 8xxx aluminum conductor alloys was investigated. Results revealed that the as-cast microstructure of 8xxx alloys was consisted of equiaxed α-Al grains and secondary Fe-rich intermetallics distributed in the interdendritic region. The extruded microstructure showed partially recrystallized structure for 0.3% Fe alloy but only dynamically recovered structures for 0.5 and 0.7% Fe alloys. With increasing Fe contents, the ultimate tensile strength and yield strength were remarkably improved, while the electrical conductivity was slightly decreased. Moreover, the creep resistance was greatly improved, which is attributed to the larger volume fraction of fine intermetallic particles and smaller subgrain size in the higher Fe-containing alloys. The creep threshold stress was found to increase from 24.6 to 33.9 MPa with increasing Fe contents from 0.3 to 0.7%, respectively. The true stress exponent values were close to 3 for all three experimental alloys, indicating that the creep mechanism of 8xxx alloys was controlled by dislocation glide.

  3. The intermetallic bonding between a ring carrier and aluminum piston alloy

    OpenAIRE

    Manasijevic, Srećko; Dolić, Natalija; Djurdjevic, Mile; Mišić, Nataša; Davitkov, Novica

    2015-01-01

    This paper presents the results of investigating the formation of intermetallic bond between a ring carrier and aluminum piston alloy. The ring carrier is made of austenitic cast iron (Ni-Resist) in order to increase the wear resistance of the first ring groove and applied in highly loaded diesel engines. Metallographic examination of the quality of alfin bond was done. A metallographic investigation using an optical microscope in combination with the SEM/EDS analysis of the quality of the in...

  4. Residual stress analysis of 7075 aluminum alloy after vacuum electron beam welding

    Institute of Scientific and Technical Information of China (English)

    Chen Furong; Xie Ruijun; Guo Guifang

    2007-01-01

    The residual stresses distribution of 7075 aluminum alloy in vacuum electron beam welding joint was numerically simulated using nonlinear finite element method. The result shows that the longitudinal residual stress is tension stress along weld center and the stress peak value appears in the middle of the welded seam; the transversal residual stress is compression stress; the residual stress in thickness direction is very small.

  5. The Hot Deformation Activation Energy of 7050 Aluminum Alloy under Three Different Deformation Modes

    OpenAIRE

    Deli Sang; Ruidong Fu; Yijun Li

    2016-01-01

    In this study, the hot deformation activation energy values of 7050-T7451 aluminum alloy, calculated with two different methods under three deformation modes, were compared. The results showed that the hot deformation activation energy values obtained with the classical constitutive equation are nearly equivalent under the hot tensile, compression, and shear-compression deformation modes. Average values exhibited an obvious increase when calculated with the modified constitutive equation beca...

  6. The plastic compressibility of 7075-T651 aluminum-alloy plate

    Science.gov (United States)

    Freed, A. D.; Sandor, B. I.

    1986-01-01

    The change in volume, and therefore the change in mass density, of an aluminum alloy was measured in uniaxial tension using clip-on extensometers. The experimental data do not agree with the assumption of plastic incompressibility found in the classical theories of plasticity. In fact, the elastic and plastic volume changes are of the same order of magnitude. Plastic anisotropy is thought to be the prime cause of this plastic compressibility.

  7. Effect of Chromate and Chromate-Free Organic Coatings on Corrosion Fatigue of an Aluminum Alloy

    Science.gov (United States)

    2012-02-20

    fatigue life [18]. In order to understand the mechanism of corrosion and corrosion fatigue of aluminum copper alloys, the morphological ...Microscopic features of fracture morphology were analyzed with scanning electron microscopy. In order to study the inhibition of these pigments...Conservation: Environmental Test Box Studies, European Cultural Heritage Newsletter on Research N2 (1988) 13–21. 63. G.O. Ilevbare, J.R. Scully, J

  8. Time-dependent corrosion fatique crack propagation in 7000 series aluminum alloys. M.S. Thesis

    Science.gov (United States)

    Mason, Mark E.

    1995-01-01

    The goal of this research is to characterize environmentally assisted subcritical crack growth for the susceptible short-longitudinal orientation of aluminum alloy 7075-T651, immersed in acidified and inhibited NaCl solution. This work is necessary in order to provide a basis for incorporating environmental effects into fatigue crack propagation life prediction codes such as NASA-FLAGRO (NASGRO). This effort concentrates on determining relevant inputs to a superposition model in order to more accurately model environmental fatigue crack propagation.

  9. Crack Initiation and Growth Behavior at Corrosion Pit in 2024-T3 Aluminum Alloy

    Science.gov (United States)

    2014-09-01

    aluminum alloy is used. It is a commonly used aircraft structure material . Tables 3.1 and 3.2 show the chemical composition and the material ...different materials and different stress ratios. Additionally, when we compare the results of the experiments done by Hunt [14] on 7075 -T6 with the...In Partial Fulfillment of the Requirements for the Degree of Master of Science in Materials Science

  10. Self-Reacting Friction Stir Welding for Aluminum Alloy Circumferential Weld Applications

    Science.gov (United States)

    Bjorkman, Gerry; Cantrell, Mark; Carter, Robert

    2003-01-01

    Friction stir welding is an innovative weld process that continues to grow in use, in the commercial, defense, and space sectors. It produces high quality and high strength welds in aluminum alloys. The process consists of a rotating weld pin tool that plasticizes material through friction. The plasticized material is welded by applying a high weld forge force through the weld pin tool against the material during pin tool rotation. The high weld forge force is reacted against an anvil and a stout tool structure. A variation of friction stir welding currently being evaluated is self-reacting friction stir welding. Self-reacting friction stir welding incorporates two opposing shoulders on the crown and root sides of the weld joint. In self-reacting friction stir welding, the weld forge force is reacted against the crown shoulder portion of the weld pin tool by the root shoulder. This eliminates the need for a stout tooling structure to react the high weld forge force required in the typical friction stir weld process. Therefore, the self-reacting feature reduces tooling requirements and, therefore, process implementation costs. This makes the process attractive for aluminum alloy circumferential weld applications. To evaluate the application of self-reacting friction stir welding for aluminum alloy circumferential welding, a feasibility study was performed. The study consisted of performing a fourteen-foot diameter aluminum alloy circumferential demonstration weld using typical fusion weld tooling. To accomplish the demonstration weld, weld and tack weld development were performed and fourteen-foot diameter rings were fabricated. Weld development consisted of weld pin tool selection and the generation of a process map and envelope. Tack weld development evaluated gas tungsten arc welding and friction stir welding for tack welding rings together for circumferential welding. As a result of the study, a successful circumferential demonstration weld was produced leading

  11. Constitutive Description of 7075 Aluminum Alloy During Hot Deformation by Apparent and Physically-Based Approaches

    Science.gov (United States)

    Mirzadeh, Hamed

    2015-03-01

    Hot flow stress of 7075 aluminum alloy during compressive hot deformation was correlated to the Zener-Hollomon parameter through constitutive analyses based on the apparent approach and the proposed physically-based approach which accounts for the dependence of the Young's modulus and the self-diffusion coefficient of aluminum on temperature. It was shown that the latter approach not only results in a more reliable constitutive equation, but also significantly simplifies the constitutive analysis, which in turn makes it possible to conduct comparative hot working studies. It was also demonstrated that the theoretical exponent of 5 and the lattice self-diffusion activation energy of aluminum (142 kJ/mol) can be set in the hyperbolic sine law to describe the peak flow stresses and the resulting constitutive equation was found to be consistent with that resulted from the proposed physically-based approach.

  12. MODELING AND EXPERIMENTAL RESEARCH OF FOUR-STRAND LOW-FREQUENCY ELECTROMAGNETIC CASTING ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    J.C. Li; B.F. Wang; J.Z. Cui

    2007-01-01

    With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density in the aluminum melt and magnetic field interaction of four coils applied with same currents were investigated. Calculating results showed that magnetic flux density in the aluminum melt was greatly improved and the magnetic field interaction among different coils was decreased when external part of mould is made of soft magnetic material. Based on the finding, a four-strand low-frequency electromagnetic casting 6063 aluminum alloy experiment was carried out in the laboratory. The experiment showed that the surface of the billet was smooth and had no exudations and cold shuts, the as-cast microstructures were fine, uniform, equiaxed, net-globular or globular under low-frequency electromagnetic field. The microstructure becomes finer with increased current value.

  13. Fatigue Crack Initiation and Propagation of Aluminum Alloy Bearings

    Institute of Scientific and Technical Information of China (English)

    CHENG Xian-Hua; MA Yan-Yan

    2004-01-01

    Observation of fatigue crack initiation and propagation during fatigue test in ALSn20Cu bearing has been presented. Journal center orbit, oil film pressure and stress distribution in alloy layer have been calculated and are taken as the basis for theoretically simulating the bearing fatigue process. It is found that the calculated results are in good accordance with the experimental results, which provides a feasible way for investigation of fatigue crack propagation process in the bearing.

  14. METAL-CERAMIC INTERFACES IN LASER COATED ALUMINUM-ALLOYS

    NARCIS (Netherlands)

    ZHOU, XB; DEHOSSON, JTM

    1994-01-01

    A novel process was developed to firmly coat an aluminium alloy, Al6061, with alpha-Al2O3 by means of laser processing. In this approach a mixture of SiO2 and Al powder was used to inject in the laser melted surface of aluminium. A reaction product alpha-Al2O3 layer of a thickness of 100 mum was cre

  15. Coating of 6028 Aluminum Alloy Using Aluminum Piston Alloy and Al-Si Alloy-Based Nanocomposites Produced by the Addition of Al-Ti5-B1 to the Matrix Melt

    Science.gov (United States)

    El-Labban, Hashem F.; Abdelaziz, M.; Mahmoud, Essam R. I.

    2014-10-01

    The Al-12 pctSi alloy and aluminum-based composites reinforced with TiB2 and Al3Ti intermetallics exhibit good wear resistance, strength-to-weight ratio, and strength-to-cost ratio when compared to equivalent other commercial Al alloys, which make them good candidates as coating materials. In this study, structural AA 6028 alloy is used as the base material. Four different coating materials were used. The first one is Al-Si alloy that has Si content near eutectic composition. The second, third, and fourth ones are Al-6 pctSi-based reinforced with TiB2 and Al3Ti nano-particles produced by addition of Al-Ti5-B1 master alloy with different weight percentages (1, 2, and 3 pct). The coating treatment was carried out with the aid of GTAW process. The microstructures of the base and coated materials were investigated using optical microscope and scanning electron microscope equipped with EDX analyzer. Microhardness of the base material and the coated layer were evaluated using a microhardness tester. GTAW process results in almost sound coated layer on 6028 aluminum alloy with the used four coating materials. The coating materials of Al-12 pct Si alloy resulted in very fine dendritic Al-Si eutectic structure. The interface between the coated layer and the base metal was very clean. The coated layer was almost free from porosities or other defects. The coating materials of Al-6 pct Si-based mixed with Al-Ti5-B1 master alloy with different percentages (1, 2, and 3 pct), results in coated layer consisted of matrix of fine dendrite eutectic morphology structure inside α-Al grains. Many fine in situ TiAl3 and TiB2 intermetallics were precipitated almost at the grain boundary of α-Al grains. The amounts of these precipitates are increased by increasing the addition of Al-Ti5-B1 master alloy. The surface hardness of the 6028 aluminum alloy base metal was improved with the entire four used surface coating materials. The improvement reached to about 85 pct by the first type of

  16. Cast aluminum alloys containing dispersions of zircon particles

    Science.gov (United States)

    Banerji, A.; Surappa, M. K.; Rohatgi, P. K.

    1983-06-01

    A process for preparing Al-alloy castings containing dispersions of zircon particles is described. Composites were prepared by stirring zircon particles (40 to 200 µm size) in commercially pure Al (99.5 pct)* and Al-11.8 pct Si melts and subsequently casting these melts in permanent molds. It was found to be necessary to alloy the above two melts with 3 pct Mg to disperse substantial amounts of zircon particles (25 to 30 pct). Further, it was possible to disperse up to 60 wt pct zircon by adding up to 5 pct Mg; however, the melts containing above 30 wt pct zircon showed insufficient fluidity for gravity diecasting and had to be pressure diecast. Microstructural studies of cast composites indicated the presence of a reaction zone at the periphery of zircon particles, and electron probe microanalysis showed concentrations of Mg and Si at the particle-matrix interface. Hardness, abrasive wear resistance, elastic modulus, 0.2 pct proof stress, and tensile strength of cast Al-3 pct Mg alloy were found to improve with the dispersions of zircon particles. Scanning electron micrographs of abraded and fractured surfaces did not show any evidence of particle pull-outs or voids at the particle matrix interface, indicating strong continuous bonding.

  17. Electrodeposition of Ni-Cr alloy on aluminum substrate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Ni-Cr alloys with mass fraction of 1.4%-23.9 %Cr, 76.1%-98.6 % Ni, and hardness of 70.5-80.5HR were electrodeposited on aluminium substrate from the trivalent chromium sulphate-chloride solution using citric acid as complexing agent. The aluminium was pretreated by means of degreasing and eroding, polishing and twice chemicai immersion of zinc. The effects of electrodeposition parameters such as current density, temperature, pH value and bath concentration on the composition and hardness of deposits were investigated. The results show that the Cr content increases with the increase of current density and the decrease of temperature, and that it increases with the increase of pH value to a maximum and then decreases. The increase of Cr content leads to the increase of hardness of the Ni-Cr layers. The deposits with high Cr content are of good corrosion resistance. Good adherence of Ni-Cr deposits to aluminium substrate is obtained. The Ni-Cr alloys are the Ni-Cr solid solution with fcc crystalline structure. The Ni-Cr alloy deposits are fine, bright and smooth and compact.

  18. Influence of wire EDM parameters on the damping behaviour of A356.2 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Dora Siva, E-mail: dorasivaprasad@gmail.com [Dept of Mechanical Engineering, GITAM University, Visakhapatnam, 530045 (India); Shoba, Chintada [Dept of Industrial Engineering, GITAM University, Visakhapatnam, 530045 (India); Varma, Kalidindi Rahul [Dept of Mechanical Engineering, RAGHU College of Engineering, Visakhapatnam (India); Khurshid, Abdul [M.Tech (CAD/CAM), Dept of Mechanical Engineering, GITAM University, Visakhapatnam, 530045 (India)

    2015-10-15

    The effect of different Wire electrical discharge machining (WEDM) process parameters on the damping behavior of A356.2 aluminum alloy is investigated. In the present investigation pulse on time (T{sub ON}), pulse off time (T{sub OFF}) and peak current (IP) which are considered to be the most significant process parameters from the previous studies are varied using one factor at a time approach, to study the effect on damping behavior of A356.2 aluminum alloy. Damping experiments are performed on a dynamic mechanical analyzer (DMA 8000) at constant strain under dual cantilever mode over a frequency range of 1–100 Hz at room temperature. The scanning electron microscope was used for characterization of the wire EDMed samples. Experimental results reveal that the damping behavior greatly depends on the wire EDM process parameters. The related mechanisms are presented. - Highlights: • Damping capacity increase with the increase in frequency. • Increasing pulse on time increases the damping capacity of aluminum alloy. • The damping capacity was found to decrease with the increase in pulse off time. • No significant change in damping capacity was noticed with varied peak current. • The formation of white layer plays an important role in the damping behavior.

  19. Energy absorption of aluminum alloy thin-walled tubes under axial impact

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hongtu; Wang, Jian [Ludong University, Yantai (China); Shen, Guozhe; Hu, Ping [Dalian University of Technology, Dalian (China)

    2016-07-15

    Aluminum alloys are important technological materials for achieving the lightweight design of automotive structures. Many works have reported on the deformation and energy absorption of thin-walled tubes. Multicorner tubes with extra concave corners in the cross section were presented in this study to improve the energy absorption efficiency of aluminum alloy thin-walled tubes. The axial crushing of square and multicorner thin-walled tubes was simulated with the same cross-sectional perimeter. The method of folding element was applied to predict the crushing behavior of the thin-walled tubes under axial impact. The corners on the cross section were discussed to determine their effect on the energy absorption performance of thin-walled tubes. Results showed that the increasing performance of energy absorption of aluminum alloy thin-walled tubes was caused by the increasing number of corners on the cross section of multicorner tubes. Both the number and size of corners had an important effect on the crushing force efficiency of multicorner tubes. The maximum crushing force efficiency of multicorner tubes was 11.6% higher than that of square tubes with the same material consumption of thin-walled tubes. The multicorner tubes with 12 corners showed better energy absorption performance than the tubes with more than 12 corners; this high number of corners could lead to the small size of corners or unstable deformations. The high energy absorption performance of multicorner tubes prefers increasing the corner number and corner size of adjacent sides at the same time.

  20. Stress-strain curves for different loading paths and yield loci of aluminum alloy sheets

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-dong; WAN Min; HAN Fei; WANG Hai-bo

    2006-01-01

    To carry out biaxial tensile test in sheet metal, the biaxial tensile testing system was established. True stress-true strain curves of three kinds of aluminum alloy sheets for loading ratios of 4:1, 4:2, 4:3, 4:4, 3:4, 2:4 and 1:4 were obtained by conducting biaxial tensile test in the established testing systems. It shows that the loading path has a significant influence on the stress-strain curves and as the loading ratio increases from 4:1 to 4:4, the stress-strain curve becomes higher and n-value becomes larger.Experimental yield points for three aluminum alloy sheets from 0.2% to 2% plastic strain were determined based on the equivalent plastic work. And the geometry of the experimental yield loci were compared with the yield loci calculated from several existing yield criteria. The analytical result shows that the Barlat89 and Hosford yield criterion describe the general trends of the experimental yield loci of aluminum alloy sheets well, whereas the Mises yield criterion overestimates the yield stress in all the contours.

  1. Study on phosphating treatment of aluminum alloy: role of yttrium oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shenglin

    2009-01-01

    Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3(yttrium oxide), were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3(PO4)2-4H2O (hopeite) and AIPO4(aluminum phosphate). Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by po-larization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.

  2. Relationship between boundary misorientation angle and true strain during high temperature deformation of 7050 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    HU Hui-e; YANG Li; ZHEN Liang; SHAO Wen-zhu; ZHANG Bao-you

    2008-01-01

    Tensile tests of solid solution treated 7050 aluminum alloy were conducted to different strain degrees (0.1, 0.4, 0.6 and failure) at 460 ℃ with the strain rate of 1.0×10-4-1.0×10-1s-1. The boundary misorientation angle evolution during hot deformation of the 7050 aluminum alloy was studied by EBSD technique and the fracture surfaces were observed using SEM. A linear relationship between the increase in the average boundary misorientation angle and the true strain at different strain rates is assumed when aluminum alloy is deformed at 460 ℃. The increasing rate of average boundary misorientation angle is 15.1-, 15.7- and -0.75- corresponding to the strain rate of 1.0×10-4, 1.0×10-2 and 0.1 s-1, respectively. The main softening mechanism is continuous dynamic recrystallization when the strain rates are 1.0×10-4 and 1.0×10-2 s-1, and it is dynamic recovery when strain rate is 0.1 s-1.

  3. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Michael D. Blanton

    2012-09-01

    Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

  4. Residual Strength of Stiffened LY12CZ Aluminum Alloy Panels with Widespread Fatigue Damage

    Institute of Scientific and Technical Information of China (English)

    Li Zhong; Ge Sen; Lu Guozhi; Chen Li; Ding Huiliang

    2008-01-01

    Experimental and analytical investigations on the residual strength of the stiffened LY12CZ aluminum alloy panels with widespread fatigue damage (WFD) are conducted. Nine stiffened LY12CZ aluminum alloy panels with three different types of damage are tested for residual strength. Each specimen is pre-cracked at rivet holes by saw cuts and subjected to a monotonically increasing tensile load until failure is occurred and the failure load is recorded. The stress intensity factors at the tips of the lead crack and the adjacent WFD cracks of the stiffened aluminum alloy panels are calculated by compounding approach and finite element method (FEM) respectively. The residual strength of the stiffened panels with WFD is evaluated by the engineering method with plastic zone linkup criterion and the FEM with apparent fracture toughness criterion respectively. The predicted residual strength agrees well with the experiment results. It indicates that in engineering practice these methods can be used for residual strength evaluation with the acceptable accuracy. It can be seen from this research that WFD can significantly reduce the residual strength and the critical crack length of the stiffened panels with WFD. The effect of WFD crack length on residual strength is also studied.

  5. Study of the Tensile Damage of High-Strength Aluminum Alloy by Acoustic Emission

    Directory of Open Access Journals (Sweden)

    Chang Sun

    2015-11-01

    Full Text Available The key material of high-speed train gearbox shells is high-strength aluminum alloy. Material damage is inevitable in the process of servicing. It is of great importance to study material damage for in-service gearboxes of high-speed train. Structural health monitoring methods have been widely used to study material damage in recent years. This study focuses on the application of an acoustic emission (AE method to quantify tensile damage evolution of high-strength aluminum alloy. First, a characteristic parameter was developed to connect AE signals with tensile damage. Second, a tensile damage quantification model was presented based on the relationship between AE counts and tensile behavior to study elastic deformation of tensile damage. Then tensile tests with AE monitoring were employed to collect AE signals and tensile damage data of nine samples. The experimental data were used to quantify tensile damage of high-strength aluminum alloy A356 to demonstrate the effectiveness of the proposed method.

  6. Characteristics of laser beam welds of age-hardenable 6061-T6 aluminum alloy

    Science.gov (United States)

    Hirose, Akio; Kobayashi, Kojiro F.

    2003-03-01

    Laser beam welding is attractive for joining age-hardenable aluminum alloys, because its low over-all heat input results in a narrow weld heat affected zone (HAZ), where softening caused by dissolution of age precipitates occurs. In the present work, 1mm-thick 6061-T6 aluminum alloy plates were welded using a 2.5 kW CO2 laser and it was experimentally proved that the width of the softened region in the laser beam weld was less than 1/7 that of a TIG weld. Moreover the hardness in the softened region of the laser beam weld was found to be almost fully recovered to the base metal hardness by applying a post-weld aging treatment at 443 K for 28.8 ks without solution annealing unlike the TIG weld. These results characterize the advantage of laser beam welding in joining of the age-hardenable aluminum alloy as compared with the conventional arc welding. The hardness distributions in the HAZ were theoretically evaluated based on kinetic equations describing the dissolution of hardening β' (Mg2Si) precipitates and the precipitation of non-hardening β' (Mg2Si) precipitates during the weld thermal cycles to quantitatively prove above mentioned advantageous characteristics of laser beam welding.

  7. Characterization of Molybdate Conversion Coatings for Aluminum Alloys by Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Calle, Luz Marina

    2000-01-01

    Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion inhibiting properties of newly developed proprietary molybdate conversion coatings on aluminum alloy 2024-T3 under immersion in aerated 5% (w/w) NaCl. Corrosion potential and EIS measurements were gathered for six formulations of the coating at several immersion times for two weeks. Nyquist as well as Bode plots of the data were obtained. The conversion-coated alloy panels showed an increase in the corrosion potential during the first 24 hours of immersion that later subsided and approached a steady value. Corrosion potential measurements indicated that formulations A, D, and F exhibit a protective effect on aluminum 2024-T3. The EIS spectra of the conversion-coated alloy were characterized by an impedance that is higher than the impedance of the bare alloy at all the immersion times. The low frequency impedance, Z(sub lf) (determined from the value at 0.05 Hz) for the conversion-coated alloy was higher at all the immersion times than that of the bare panel. This indicates improvement of corrosion resistance with addition of the molybdate conversion coating. Scanning electron microscopy (SEM) revealed the presence of cracks in the coating and the presence of cubic crystals believed to be calcium carbonate. Energy dispersive spectroscopy (EDS) of the test panels revealed the presence of high levels of aluminum, oxygen, and calcium but did not detect the presence of molybdenum on the test panels. X-ray photoelectron spectroscopy (XPS) indicated the presence of less than 0.01 atomic percent molybdenum on the surface of the coating.

  8. Production of Magnesium and Aluminum-Magnesium Alloys from Recycled Secondary Aluminum Scrap Melts

    Science.gov (United States)

    Gesing, Adam J.; Das, Subodh K.; Loutfy, Raouf O.

    2016-02-01

    An experimental proof of concept was demonstrated for a patent-pending and trademark-pending RE12™ process for extracting a desired amount of Mg from recycled scrap secondary Al melts. Mg was extracted by electrorefining, producing a Mg product suitable as a Mg alloying hardener additive to primary-grade Al alloys. This efficient electrorefining process operates at high current efficiency, high Mg recovery and low energy consumption. The Mg electrorefining product can meet all the impurity specifications with subsequent melt treatment for removing alkali contaminants. All technical results obtained in the RE12™ project indicate that the electrorefining process for extraction of Mg from Al melt is technically feasible. A techno-economic analysis indicates high potential profitability for applications in Al foundry alloys as well as beverage—can and automotive—sheet alloys. The combination of technical feasibility and potential market profitability completes a successful proof of concept. This economical, environmentally-friendly and chlorine-free RE12™ process could be disruptive and transformational for the Mg production industry by enabling the recycling of 30,000 tonnes of primary-quality Mg annually.

  9. Effect of bariun on the refinement of primary aluminum and eutectics in a hypoeutectic Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    LI Wei; FAN Hongyuan; ZHANG Xianju; SHEN Baoluo

    2003-01-01

    The effect of barium on the refinement of primary aluminum and on the modification of eutectics in a hypoeutectic aluminm-silicon alloy was investigated. The results indicate that barium not only modifies the eutectic silicon but also refines the primary aluminum and there is a relationship between the retained barium and the second spacing of primary aluminum. Experiments of barium-treated commercial Al-Si hypoeutectic alloy show that barium is a better modifier than sodium when there is a longer holding time.

  10. Research progress on microstructure evolution of semi-solid aluminum alloys in ultrasonic field and their rheocasting

    Directory of Open Access Journals (Sweden)

    Wu Shusen

    2014-07-01

    Full Text Available The effects of ultrasonic vibration (UV treatment on microstructure of semi-solid aluminum alloys and the application of UV in rheocasting process are reviewed. Good semi-solid slurry can be produced by high-intensity UV process for aluminum alloys. The microstructures of Al-Si, Al-Mg and Al-Cu alloys produced by rheocasting assisted with UV are compact and with fine grains. The mechanical properties of the UV treated alloys are increased by about 20%-30%. Grain refinement of the alloys is generally considered because of cavitation and acoustic streaming caused by UV. Apart from these mechanisms, a hypothesis of the fuse of dendrite root caused by capillary infiltration in the ultrasonic field, as well as a mechanism of crystallites falling off from the mould-wall and crystal multiplication by mechanical vibration effect in indirect ultrasonic vibration are proposed to explain the microstructure evolution of the alloys.

  11. Nanomechanical properties of friction stir welded AA6082-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Koumoulos, E.P. [National Technical University of Athens, Department of Chemical Engineering 9 Heroon, Polytechneiou st., Zografos, Athens, GR-157 80 (Greece); Charitidis, C.A., E-mail: charitidis@chemeng.ntua.gr [National Technical University of Athens, Department of Chemical Engineering 9 Heroon, Polytechneiou st., Zografos, Athens, GR-157 80 (Greece); Daniolos, N.M.; Pantelis, D.I. [National Technical University of Athens, Department of Naval Architecture and Marine Engineering 9 Heroon, Polytechneiou st., Zografos, Athens, GR-157 80 (Greece)

    2011-11-25

    Lightweight alloys are of major concern, due to their functionality and applications in transport and industry applications. Friction stir welding (FSW) is a solid-state welding process for joining aluminum and other metallic alloys and has been employed in aerospace, rail, automotive and marine industries. Compared to the conventional welding techniques, FSW produces joints which do not exhibit defects caused by melting. The objective of the present study is to investigate the surface hardness (H) and elastic modulus (E) in friction stir welded aluminum alloy AA6082-T6. The findings of the present study reveal that the welding process softens the material, since the weld nugget is the region where the most deformations are recorded (dynamic recrystallization, production of an extremely fine, equiaxial structure), confirmed by optical microscopy and reduced nanomechanical properties in the welding zone. A yield-type pop-in occurs upon low loading and represents the start of phase transformation, which is monitored through a gradual slope change of the load-displacement curve. Significant pile-up is recorded during nanoindentation of the alloy through SPM imaging.

  12. Effect of porosity on the tensile properties of low ductility aluminum alloys

    Directory of Open Access Journals (Sweden)

    Gustavo Waldemar Mugica

    2004-06-01

    Full Text Available The literature contains reports of several studies correlating the porosity and mechanical properties of aluminum alloys. Most of these studies determine this correlation based on the parameter of global volumetric porosity. These reports, however, fail to separate the effects of microstructural features and porosity on alloys, though recognizing the influence of the latter on their mechanical properties. Thus, when the decrease in tensile strength due to the porosity effect is taken into account, the findings are highly contradictory. An analysis was made of the correlation between mechanical properties and global volumetric porosity and volumetric porosity in the fracture, as well as of the beta-Al5FeSi phase present in 380 aluminum alloy. Our findings indicate that mechanical properties in tension relating to global volumetric porosity lead to overestimations of the porosity effect in detriment to the mechanical properties. Moreover, the proposed models that take into account the effects of particles, both Si and beta-Al5FeSi, are unapplicable to low ductility alloys.

  13. The Effects of Retrogression and Reaging on Aluminum Alloy 2195

    Science.gov (United States)

    Ward, N.; Tran, A.; Abad, A.; Lee, E. W.; Hahn, M.; Fordan, E.; Es-Said, O.

    2011-08-01

    A retrogression and reaging (RRA) treatment was performed on 2195 Al-Li Alloy. The exposure times were from 5 to 60 min, and the temperatures were from 200 to 250 °C. Samples that were exposed to a salt spray test had overall similar mechanical properties as compared to those that were not exposed. The percent elongation, however, was significantly deteriorated due to the salt spray exposure. The mechanical properties of the 2195 samples were compared to those of 2099 samples exposed to similar treatments in an earlier study.

  14. Effects of process parameters on numerical control bending process for large diameter thin-walled aluminum alloy tubes

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; YANG He; ZHAN Mei; XU Xu-dong; LI Guang-jun

    2009-01-01

    Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.

  15. Composition and hardness of mullite coatings formed with direct current power supply on LY12 aluminum alloy surface

    Institute of Scientific and Technical Information of China (English)

    XIN Shi-gang; JIANG Zhao-hua; LI Yan-ping; ZHANG Ji-lin

    2005-01-01

    The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated. Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-plasma oxidation (MPO) technique. In this work, the composition, microstructure and elemental distribution of ceramic coatings formed by MPO on LY 12 aluminum alloy and its hardness are investigated using XRD, EPMA and microhardness instruments. The results show that the ceramic coatings consist of mullite, γ -Al2 O3 and a lot of amorphous matter. The content of silicon in the coatings increases from interface to the coatings, however, the content of aluminum decreases along this direction. The maximum hardness of ceramic coatings is up to 9. 2 GPa.

  16. Microarc Oxidation of the High-Silicon Aluminum AK12D Alloy

    Directory of Open Access Journals (Sweden)

    S. K. Kiseleva

    2015-01-01

    Full Text Available The aim of work is to study how the high-silicon aluminum AK12D alloy microstructure and MAO-process modes influence on characteristics (microhardness, porosity and thickness of the oxide layer of formed surface layer.Experimental methods of study:1 MAO processing of AK12D alloy disc-shaped samples. MAO modes features are concentration of electrolyte components – soluble water glass Na2SiO3 and potassium hydroxide (KOH. The content of two components both the soluble water glass and the potassium hydroxide was changed at once, with their concentration ratio remaining constant;2 metallographic analysis of AK12D alloy structure using an optical microscope «Olympus GX51»;3 image analysis of the system "alloy AK12D - MAO - layer" using a scanning electron microscope «JEOL JSM 6490LV»;4 hardness evaluation of the MAO-layers using a micro-hardness tester «Struers Duramin».The porosity, microhardness and thickness of MAO-layer formed on samples with different initial structures are analyzed in detail. Attention is paid to the influence of MAO process modes on the quality layer.It has been proved that the MAO processing allows reaching quality coverage with high microhardness values of 1200-1300HV and thickness up to 114 μm on high-silicon aluminum alloy. It has been found that the initial microstructure of alloy greatly affects the thickness of the MAO - layer. The paper explains the observed effect using the physical principles of MAO process and the nature of silicon particles distribution in the billet volume.It has been shown that increasing concentration of sodium silicate and potassium hydroxide in the electrolyte results in thicker coating and high microhardness.It has been revealed that high microhardness is observed in the thicker MAO-layers.Conclusions:1 The microstructure of aluminum AK12D alloy and concentration of electrolyte components - liquid glass Na2SiO3 and potassium hydroxide affect the quality of coating resulted from MAO

  17. Effect of Post-Weld Heat Treatment on the Mechanical Properties of Friction Stir Welds of Dissimilar Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    P. Murali Krishna

    2011-07-01

    Full Text Available This paper focuses on the effect of post weld heat treatment (PWHT on microstructure and mechanical properties of dissimilar friction stir welding (FSW of AA2024-T6 to AA6351-T6. FSW is getting widened to be used to join the aluminum alloys. PWHT of AA2024 and AA6351 aluminum alloys are not reported so far even though these alloys are widely used in aerospace and automobile industries. A post weld solution treatment and subsequent ageing resulted in improvement in mechanical properties (hardness and tensile strength.

  18. Mold Materials For Permanent Molding of Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    John F Wallace; David Schwam; Wen Hong dxs11@po.cwru.edu

    2001-09-14

    A test that involves immersion of the potential mod materials for permanent molds has been developed that provides a thermal cycle that is similar to the experienced during casting of aluminum in permanent molds. This test has been employed to determine the relative thermal fatigue resistance of several different types of mold materials. Four commercial mold coatings have been evaluated for their insulating ability, wear resistance and roughness. The results indicate that composition and structure of the mold materials have considerable effect on their thermal fatigue cracking behavior. Irons with a gray iron structure are the most prone to thermal fatigue cracking followed by compacted graphite irons with the least thermal fatigue cracking of the cast irons experienced by ductile iron. The composition of these various irons affects their behavior.

  19. Improvement on the Corrosion Resistance of AZ91D Magnesium Alloy by Aluminum Diffusion Coating

    Institute of Scientific and Technical Information of China (English)

    Hongwei HUO; Ying LI; Fuhui WANG

    2007-01-01

    By combination of magnetron sputtering deposition and vacuum annealing, an aluminum diffusion coating was prepared on the substrate of AZ91D alloy to improve its corrosion resistance. The microstructure and composition of the diffusion coating was investigated by scanning electron microscopy and X-ray diffraction. The diffusion coating was mainly comprised of β phase-Al12Mg17. The continuous immersion test in 3.5 wt pct neutral NaCl solution indicated that the specimen with diffusion coating had better corrosion resistance compared with the bare AZ91D alloy specimen. The potentiodynamic polarization measurement indicated that the diffusion coating could function as an effectively protective layer to reduce the corrosion rate of AZ91D alloy when exposed to 3.5 wt pct NaCl solution.

  20. Laser surface infiltration of tungsten-carbide in steel and aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dahotre, N.B.; Mukherjee, K. (Michigan State Univ., East Lansing (USA))

    It has been demonstrated that surface modification in metals and alloys can be achieved by laser melting in conjunction with injection of particulate alloying elements in the heated zone. In our current experiments the authors have successfully implanted tungsten-carbide particles on the surface of several grades of carbon-steels as well as on the surface of a structural aluminum alloy. In both cases a significant increase in microhardness has been detected. Hardness profile from the interaction zone to the heat affected zone (HAZ) has been determined. The microstructural features of both the implanted zone and HAZ also have been determined. Effect of laser input energy, nature of tungsten-carbide particle size, size distribution and method of powder injection on the hardness profile have been investigated. Some preliminary examination of surface wear of such implanted material is also conducted. These results are discussed in detail.

  1. Deformation character of the aluminum alloy AA 6063 depending on the homogenization state

    Energy Technology Data Exchange (ETDEWEB)

    Kelesoglu, Erguen [Yildiz Technical Univ. (Turkey). Research and Development Centre for Industrial Cooperation; Erarslan, Yaman [Metallurgical and Materials Engineering, Yildiz Technical Univ. (Turkey); Oezer, Goekhan [Metallurgical and Materials Engineering, Yildiz Technical Univ. (Turkey); Yildiz Technical Univ. (TR). Balkan Centre of Advanced Casting Technologies (BCACT)

    2009-07-01

    In the work for this contribution, homogenization heat treatment was evaluated with respect to its effect on deformation ability of AA6063 aluminum alloy which is a widely used extrusion alloy. The samples machined from extrusion billets were homogenized at 540 C, 560 C and 580 C for a time period of 2, 4, 6, 8 and 10 h. The homogenization state of the samples was assessed via microstructure examination. The hardness of the samples was determined using Brinell hardness method. Tensile test was carried out in order to evaluate the deformation ability. Tensile strength and elongation at rupture were compared depending on the homogenization state of the alloy. Depending on the homogenization grade, the elongation at rupture was increased, and samples showed a gradual shift from brittle fracture to ductile fracture. (orig.)

  2. The Effect of Aluminum Content on the Microstructure and Cavitation Wear of Feal Intermetallic Alloys

    Directory of Open Access Journals (Sweden)

    Jasionowski Robert

    2014-03-01

    Full Text Available Intermetallic-based alloys (so called intermetallics of the Fe-Al binary system are modern construction materials, which in recent decades have found application in many branches of the power, chemical and automotive industries. High resistance of FeAl based alloys to cavitational erosion results first of all from their high hardness in the as-cast state, large compressive stresses in the material, as well as homogeneous structure. In the present paper, the effect of aluminum content on the microstructure, texture and strain implemented upon cavitation wear of FeAl intermetallic alloys, have been analyzed by field emission gun scanning electron microscopy (FEG SEM and electron backscatter diffraction (EBSD analysis. Obtained results of structural characterization indicates that with increasing aluminium content effects of orientation randomization (weakening of //ND casting texture, grain refinement and rising of mechanical strenght (and so cavitational resistance take place.

  3. EXPERIMENTAL INVESTIGATION ON ELECTRICAL DISCHARGE MACHINING OF TITANIUM ALLOY USING COPPER, BRASS AND ALUMINUM ELECTRODES

    Directory of Open Access Journals (Sweden)

    S. DHANABALAN

    2015-01-01

    Full Text Available In the present study, an evaluation has been done on Material Removal Rate (MRR, Surface Roughness (SR and Electrode Wear Rate (EWR during Electrical Discharge Machining (EDM of titanium alloy using copper, brass and aluminum electrodes. Analyzing previous work in this field, it is found that electrode wear and material removal rate increases with an increase current. It is also found that the electrode wear ratio increases with an increase in current. The higher wear ratio is found during machining of titanium alloy using a brass electrode. An attempt has been made to correlate the thermal conductivity and melting point of electrode with the MRR and electrode wear. The MRR is found to be high while machining titanium alloy using brass electrode. During machining of titanium alloy using copper electrodes, a comparatively smaller quantity of heat is absorbed by the work material due to low thermal conductivity. Due to the above reason, the MRR becomes very low. Duringmachining of titanium alloy using aluminium electrodes, the material removal rate and electrode wear rate are only average value while machining of titanium alloy using brass and copper electrodes.

  4. Mechanical Properties of Solid-State Recycled 4xxx Aluminum Alloy Chips

    Science.gov (United States)

    Tokarski, Tomasz

    2016-08-01

    The direct production of aluminum from bauxite ores is known to be a very energetic-intensive operation compared to other metallurgical processes. Due to energy issues and the rapid increase in aluminum demand, new kinds of aluminum production processes are required. Aluminum waste recycling, which has an advantage of lowering the cost of electric power consumption, is considered to be an alternative route for material manufacturing. In this work, the way of reusing aluminum EN-AC 44000 alloy scraps by hot extrusion was presented. Metal chips of different sizes and morphology were cold compacted into billet form and then hot extruded. Mechanical properties investigations combined with microstructure observations were performed. Mechanical anisotropy behavior of material was evaluated on the base of tensile test experiments performed on samples machined at 0°, 45°, and 90°, respectively, to the extrusion direction. It was found that the initial size of the chips has an influence on the mechanical properties of the received profiles. Samples produced from fine chips revealed higher tensile strength in comparison to larger chips, which can be attributed to a refined microstructure containing fine, hard Si particles and Fe-rich intermetallic phases. Finally, it was found that anisotropic behavior of chip-based profiles is similar to conventionally cast and extruded materials which prove good bonding quality between chips.

  5. Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel

    Institute of Scientific and Technical Information of China (English)

    San-bao LIN; Jian-ling SONG; Guang-chao MA; Chun-li YANG

    2009-01-01

    Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel was investigated, and the wettability and spreadability of aluminum filler metal on the steel surface were analyzed. The resultant joint was characterized in order to determine the brittle intermetallic compound (IMC) in the interfacial layer, and the mechan-ical property of the joint was tested. The results show that the zinc coated layer can improve the wettability and spreadability of liquid aluminum filler metal on the surface of the steel, and the wetting angle can reach less than 20°. The lap joint has a dual characteristic and can be divided into a welding part on the aluminum side and a brazing part on the steel side. The interfacial IMC layer in the steel side is about 9.0 μm in thickness, which transfers from (α-Al + FeAl3) in the welded seam side to (Fe2Al5+ FeAl2) and (FeAl2+ FeAl) in the steel side. The crystal grain of the welded seam is obviously larger in size in the aluminum side. The local incomplete brazing is found at the root of the lap joint, which weakens the property of the joint. The fracture of the joint occurs at the root and the average tensile strength reaches 90 MPa.

  6. Preparation of casting alloy ZL101 with coarse aluminum-silicon alloy

    Institute of Scientific and Technical Information of China (English)

    YOU Jing; WANG Yao-wu; FENG Nai-xiang; YANG Ming-sheng

    2008-01-01

    The coarse Al-Si alloy produced by carbothermal reduction of aluminous ore contains 55% Al, 25% Si and some impurities. The main impurities are slag and iron. The process of manufacturing casting Al-Si alloy ZL101 with the coarse Al-Si alloy was studied. The phase constitution and microstructure of the coarse Al-Si alloy, slag and ZL101 were examined by X-ray diffractometry and scanning electron microscopy. The results show that the content of silicon and iron in the casting alloy reduces with the increase of the dosage of purificant and manganese, but increases with the rise of filtering temperature. It is found that casting Al-Si alloy conforming to industrial standard can be produced after refining by using purificant, and removing iron by using manganese and added magnesium.

  7. Springback analysis on AA 6061 aluminum alloy sheets

    Science.gov (United States)

    Ramulu, Perumalla Janaki; Rao, P. Srinivasa; Yimer, Wassihun

    2016-10-01

    In automotive industry, sheet metal forming process play a key role with respect to economy and weight reduction ratio. In sheet metal forming, one of the operations is bending operation in which sheet will not go under sever deformation. The end components are made by applying the continuous load on the sheet in the bending process. In bending process, elastic limits of materials are exceeded, but flow limit thereof cannot be exceeded. Therefore, the material still keeps a portion of its original flexibility character. When the load is released, the material on forcing compress side tries to enlarge, whereas the material on tensile side tries to shrink. As a result, the material tries to spring back and the bended material by flexing slightly tries to open. Springback varies according to thickness of the material, material and process parameters, type of material, period when punch load stays on the material, dimensions of die, force applied, and bending radius. In order to make bending at a desired angle, springback amounts should be avoided. In the present work, experimentation on AA 6061 alloy sheet springback analysis has done with seven different rolling directions. Results are noted with respect to load, displacement, and die angle on the springback effect. It observed that springback affect is existed notably in the AA 6061 alloys with respect to die angle.

  8. Aluminum alloy production for the reinforcement of the CMS conductor

    CERN Document Server

    Sequeira-Lopes-Tavares, S; Campi, D; Curé, B; Horváth, I L; Riboni, P; Sgobba, Stefano; Smith, R P

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the Large Hadron Collider (LHC) project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. To reinforce the high-purity (99.998%) Al-stabilized conductor of the magnet against the magnetic loadings experienced during operation at 4.2 K, two continuous sections of Al-alloy (AA) reinforcement are Electron Beam (EB) welded to it. The reinforcements have a section of 24*18 mm and are produced in continuous 2.55 km lengths. The alloy EN AW-6082 has been selected for the reinforcement due to its excellent extrudability, high strength in the precipitation hardened states, high toughness and strength at cryogenic temperature and good EB weldability. Each of the continuous lengths of the reinforcement is extruded billet on billet and press quenched on-line from the extrusion temperature in an industrial extrusion plant. In order to insure the ready EB welda...

  9. Fabricating a n+-Ge contact with ultralow specific contact resistivity by introducing a PtGe alloy as a contact metal

    Science.gov (United States)

    Hsu, C. C.; Chou, C. H.; Wang, S. Y.; Chi, W. C.; Chien, C. H.; Luo, G. L.

    2015-09-01

    In this study, we developed an Ohmic contact structure to an in situ n+-Ge film that has an ultralow specific contact resistivity of [(6.8 ±2.1 ) ×10-8 Ωṡcm2] . This structure was developed by introducing a PtGe alloy as the contact metal. We observed that Ohmic contact behavior can be achieved with several other metals, and the contact resistance is related to the work function of the metal. A physical model of the band diagram was created for the Schottky tunneling width, which can provide insight into the validation and explanation of work function-dependent specific contact resistivity. Dopant segregation at the interface and increased interface roughness induced by the formation of the alloy are crucial in further reducing the specific contact resistivity. As a result, a stable PtGe alloy and high doping concentration in Ge are critical in pursuing a lower contact resistance for a Ge n-channel device.

  10. Superplasticity and cavitation in an aluminum-magnesium alloy

    Science.gov (United States)

    Bae, Donghyun

    2000-10-01

    Fundamental issues related to the forming performance of superplastic metals include the mechanisms of flow and cavitation occurring during the forming process. Cavitation beyond a critical amount is damaging to the mechanical behavior of fabricated parts. Therefore, the role of process parameters which influence cavitation must be precisely documented and understood. In this study, (1) the mechanism of deformation, (2) cavity formation and growth, and (3) the effect of forming parameters on cavitation are systematically investigated in a fine grain Al-4.7%Mg-0.8%Mn-0.4%Cu alloy. The mechanical flow response of the alloy is characterized by a new type of step strain-rate test which preserves the initial microstructure of the alloy. Under isostructural condition, sigmoidal log s vs. log 3˙ relationship is determined and then analyzed by using a grain-mantle based quantitative model1 for superplastic flow. The activation energies in both grain-mantle creep and core creep are analyzed, and the overall controlling mechanism is found to be dislocation glide and climb. Grain-mantle creep rate in the low strain-rate region is found to be enhanced many times due to a high concentration of vacancies near grain boundaries. Cavitation caused by superplastic straining under uniaxial tension is evaluated by the SEM (for frame associated with superplastic deformation. In the model, faster cavity growth is predicted for lower m and for smaller cavity density when cavity stress fields are not overlapping. Observed cavitation quantitatively agrees with the present model, but diffusional growth is found to be too slow, which cannot explain the observed nanoscale void growth behavior. Another parameter affecting the degree of cavitation is the imposed stress-state. Cavity growth rate as well as cavity nucleation rate increase with the level of mean hydrostatic tension. For a fixed cavitation volume fraction, V, the principal surface strains, 31 and 32 , for the various stress

  11. Fatigue properties of an 1421 aluminum alloy processed by ECAE

    Science.gov (United States)

    Mogucheva, A.; Kaibyshev, R.

    2010-07-01

    Fatigue properties and fatigue crack growth rate were examined in an Al-Mg-Li-Sc-Zr allow subjected to equal channel angular extrusion (ECAE) with rectangular shape of channels up to a total strain of ~4 at a temperature of 325°C followed by solution treatment with subsequent oil quenching with aging. After this processing the fraction recrystallized was ~80pct; the deformed microstructure remains essentially unchanged under solution treatment due to high density of Al3Sc coherent dispersoids playing a role of effective pinning agents. It was shown that the fatigue limit of this material attained a value of ~185 MPa. Thermomechanical processing provided a decrease in fatigue crack propagation growth rate and an increase in the stress intensity factor, K1c, in comparison with extruded bar. However, characteristics of crack propagation resistance did not attain values suitable for application of this alloy for critical aircraft components.

  12. Fatigue properties of an 1421 aluminum alloy processed by ECAE

    Energy Technology Data Exchange (ETDEWEB)

    Mogucheva, A; Kaibyshev, R, E-mail: mogucheva@bsu.edu.r [Belgorod State University, Pobeda 85, Belgorod, 308015 (Russian Federation)

    2010-07-01

    Fatigue properties and fatigue crack growth rate were examined in an Al-Mg-Li-Sc-Zr allow subjected to equal channel angular extrusion (ECAE) with rectangular shape of channels up to a total strain of {approx}4 at a temperature of 325{sup 0}C followed by solution treatment with subsequent oil quenching with aging. After this processing the fraction recrystallized was {approx}80pct; the deformed microstructure remains essentially unchanged under solution treatment due to high density of Al{sub 3}Sc coherent dispersoids playing a role of effective pinning agents. It was shown that the fatigue limit of this material attained a value of {approx}185 MPa. Thermomechanical processing provided a decrease in fatigue crack propagation growth rate and an increase in the stress intensity factor, K{sub 1c}, in comparison with extruded bar. However, characteristics of crack propagation resistance did not attain values suitable for application of this alloy for critical aircraft components.

  13. Comparison of Al electromigration in conventional Al alloy and W-plug contacts to silicon

    Science.gov (United States)

    Oates, A. S.; Martin, E. P.; Alugbin, D.; Nkansah, F.

    1993-06-01

    We examine the impact of the presence of a W plug on electromigration-induced voiding of the Al alloy layer of contacts to silicon. By comparing conventional Al alloy and W-plug contacts we show that the presence of the plug does not significantly improve the intrinsic susceptibility of contacts to Al voiding despite the elimination of the Al step coverage problem. Both the conventional Al alloy and W-plug contacts degrade by drift of the Al layer with a velocity that is not influenced by the contact structure. The sheet resistance of the underlayer material of multilayer conductors plays an important role in influencing failure times since it determines the rate of resistance increase due to electromigration.

  14. Effect of creep-aging on precipitates of 7075 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.C., E-mail: yclin@csu.edu.cn [School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083 (China); State Key Laboratory of Material Processing and Die and Mould Technology, Wuhan 430074 (China); Jiang, Yu-Qiang; Chen, Xiao-Min; Wen, Dong-Xu [School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083 (China); Zhou, Hua-Min [State Key Laboratory of Material Processing and Die and Mould Technology, Wuhan 430074 (China)

    2013-12-20

    The creep-aging behaviors of 7075 aluminum alloy are studied by uniaxial tensile creep experiments under elevated temperatures. The effects of creep-aging temperature and applied stress on the precipitates of 7075-T651 aluminum alloy are investigated using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Results show that (1) coarse insoluble precipitates (Al{sub 7}Cu{sub 2}Fe and Mg{sub 2}Si) and intermediate precipitates (Al{sub 18}Mg{sub 3}Cr{sub 2} and Al{sub 3}Zr) are found in the aluminum matrix, and the effects of creep-aging treatment on these precipitates are not obvious; (2) the main aging precipitates are η′ and η phases, and the amount of aging precipitates increase with the increase of creep-aging temperature and applied stress; (3) with the increase of creep-aging temperature and applied stress, the precipitates are discontinuously distributed on the grain boundary, and the width of precipitate free zone increases with the increase of creep-aging temperature and applied stress and (4) compared with the microstructure in the traditional stress-free aged sample, the creep-aging process can refine the precipitates and narrow the width of the precipitate free zone.

  15. Physical Simulation Method for the Investigation of Weld Seam Formation During the Extrusion of Aluminum Alloys

    Science.gov (United States)

    Fang, Gang; Nguyen, Duc-Thien; Zhou, Jie

    2016-12-01

    Extrusion through the porthole die is a predominant forming process used in the production of hollow aluminum alloy profiles across the aluminum extrusion industry. Longitudinal weld seams formed during the process may negatively influence the quality of extruded profiles. It is therefore of great importance to understand the formation of weld seams inside the welding chamber during extrusion, as affected by extrusion process variables and die design. Previously developed physical simulation methods could not fully reproduce the thermomechanical conditions inside the welding chamber of porthole die. In this research, a novel physical simulation method for the investigation of weld seam formation during extrusion was developed. With a tailor-designed tooling set mounted on a universal testing machine, the effects of temperature, speed, and strain on the weld seam quality of the 6063 alloy were investigated. The strains inside the welding chamber were found to be of paramount importance for the bonding of metal streams, accompanied by microstructural changes, i.e., recovery or recrystallization, depending on the local deformation condition. The method was shown to be able to provide guidelines for the design of porthole dies and choice of extrusion process variables, thereby reducing the scrap rate of aluminum extrusion operation.

  16. Corrosion Evaluation of Aluminum Alloys in Deionized Water

    Energy Technology Data Exchange (ETDEWEB)

    VORMELKER, PHILIPR.

    2004-09-24

    Spent nuclear fuels from foreign and domestic research and test reactors being returned to SRS are now stored with other nuclear materials in the L-basin at the Savannah River Site (SRS). Recent efforts have consolidated the fuel storage systems and L-basin has become the SRS site for water storage of spent nuclear fuels. Corrosion surveillance of coupons in this basin is being performed to provide assurance of safe storage of spent fuel. This paper describes the highlights of recent studies on these aluminum coupons after immersion for more than 7 years in L-basin. Selected coupons were metallurgically characterized to establish the existence of general corrosion and pitting. Pitting was observed on galvanically coupled samples and also on intentionally creviced coupons, thus demonstrating that localized concentration cells were formed during the exposure period. In these cases, the susceptibility to pitting was not attributed to aggressive basin water chemistry but to local condition s (crevices and galvanic coupling) that allowed the development of oxygen and/or metal ion concentration cells that produced locally aggressive waters. General corrosion was also observed on some of the coupons that had not been treated to enhance the protective oxide prior to exposure in the basin water. These observations demonstrate that, even when the basin water chemistry is rigorously controlled, localized aggressive conditions can develop. Although this demonstration does not suggest significant deterioration of the stored spent nuclear fuels, it does illustrate the potential for corrosion induced degradation and thus the importance of a routine surveillance program.

  17. Effects of V addition on recrystallization resistance of 7150 aluminum alloy after simulative hot deformation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Jing; Shi, Cangji; Chen, X.-Grant, E-mail: xgrant_chen@uqac.ca

    2014-10-15

    The effects of different V contents (0.01 to 0.19 wt.%) on the recrystallization resistance of 7150 aluminum alloys during post-deformation heat treatment were investigated. The microstructural evolutions at as-cast, as-homogenized conditions and after post-deformation annealing were studied using optical, scanning electron and transmission electron microscopes and using the electron backscattered diffraction technique. The precipitation of Al{sub 21}V{sub 2} dispersoids was observed in alloys containing 0.11 to 0.19 wt.% V after homogenization. The dispersoids were mainly distributed in the dendrite cells, and the precipitate-free zones occurred in the interdendritic regions and near grain boundaries. V addition could significantly enhance the recrystallization resistance during post-deformation annealing, particularly in the presence of a great number of Al{sub 21}V{sub 2} dispersoids. Recrystallized grain growth was effectively restricted because of the dispersoid pinning effect. The alloy containing 0.15 wt.% V exhibited the highest recrystallization resistance amongst all V-containing alloys studied. - Highlights: • Investigated the effect of V level on microstructure and flow stress of 7150 alloys • Characterized microstructures using optical microscopy, SEM, TEM and EBSD • Described the precipitation behavior of V-dispersoids in the dendritic structure • Studied the V effect on recrystallization resistance during post heat treatment • V addition greatly enhanced the recrystallization resistance during annealing.

  18. Studies on the effect of vibration on hot cracking and Grain size in AA7075 Aluminum alloy Welding

    Directory of Open Access Journals (Sweden)

    BALASUBRAMANIAN.K

    2011-01-01

    Full Text Available The aim of this present study is to investigate the vibration effect which is applied during Gas tungsten Arc welding (GTAW welding in order to improve the quality of high strength Aluminum alloy weldment. An important metallurgical difficulty in arc welding of high strength aluminum alloys is formation of hot cracking. When Aluminum alloy is welded by GTAW process, weld fusion zone shows coarse columnar grains during weld metal solidification. This often leads to poor resistance to hot cracking. In this work, an attempt is made to reduce the hot cracking and to refine the fusion zone grains in welding of aluminum alloys through vibratory treatment. The material used for the investigation is AA7075 aluminum alloy, which is highly prone for hot cracking. Vibratory treatment was carried out in the frequency range of 100Hz to 2050Hz. Weldments made with and without vibratory treatment were compared using weld cracking tests and other characterization tests like micro structural analysis, hardness measurements. Test results show that by applying vibratory treatment, hot cracking can be largely controlled in arc welding.

  19. Surface passivation of aluminum alloy 6061 with gaseous trichlorosilane: A surface investigation

    Energy Technology Data Exchange (ETDEWEB)

    Ngongang, Rickielle, E-mail: rickielle.ngongang@airliquide.com [Centre de Recherche Claude Delorme, Air Liquide, 1 Chemin de la Porte des Loges Les-Loges en Josas, 78350 Jouy-en-Josas (France); Laboratoire de Réactivité de Surface, UMR CNRS 7197, UPMC (Université Pierre et Marie Curie-Paris 6), site d’Ivry, 3 rue Galilée, 94200 Ivry-sur-Seine (France); Marceau, Eric; Carrier, Xavier; Pradier, Claire-Marie; Methivier, Christophe [Laboratoire de Réactivité de Surface, UMR CNRS 7197, UPMC (Université Pierre et Marie Curie-Paris 6), site d’Ivry, 3 rue Galilée, 94200 Ivry-sur-Seine (France); Blanc, Jean-Luc; Carre, Martine [Centre de Recherche Claude Delorme, Air Liquide, 1 Chemin de la Porte des Loges Les-Loges en Josas, 78350 Jouy-en-Josas (France)

    2014-02-15

    A molecular-scale investigation of the interaction at room temperature between gaseous trichlorosilane (HSiCl{sub 3}), used as a passivating agent, and surfaces of aluminum alloy AA6061 in a polished or hydroxylated state is conducted. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) provide information on the topography and morphology of AA6061 before and after hydroxylation and surface passivation, while surface chemistry has been investigated by Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) and X-ray photoelectron spectroscopy (XPS). Oxidation and hydroxylation of the polished alloy surface in boiling water strongly modifies the roughness of the surface, with formation of platelets and needles of oxyhydroxide AlOOH. PM-IRRAS and XPS reveal that, upon adsorption, HSiCl{sub 3} dissociates and mainly forms HSiOH{sub n}(OAl){sub 3−n}, HSi(OSi){sub n}(OAl){sub 3−n} and condensed HSiO{sub x} species, by reaction with -OH groups from the AlOOH surface phase. The amount of deposited Si-containing species is larger on the rough surface of the hydroxylated alloy and this deposit is accompanied by a decrease of the amount of free -OH groups evidenced by PM-IRRAS. These results can find applications in the field of functionalization of aluminum alloys. It is suggested that a homogeneous oxidation of the alloy surface prior to exposure to gaseous HSiCl{sub 3} may enhance the adsorption of the passivating agent.

  20. Prediction of low-cycle fatigue-life by acoustic emission—1: 2024-T3 aluminum alloy, and —2: 7075-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Baram, J. [Ben-Gurion Univ. of the Negev, Beer Sheva (Israel). Materials Engineering Division; Rosen, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials and Molecular Research Division

    1981-01-01

    1: In this paper, low-cycle fatigue tests were conducted by tension-tension until rupture, on a 2024-T3 aluminum alloy sheet. Initial crack sizes and orientations in the fatigue specimens were found to be randomly distributed. Acoustic emission was continuously monitored during the tests. Every few hundred cycles, the acoustic signal having the highest peak-amplitude, was recorded as an extremal event for the elapsed period. This high peak-amplitude is related to a fast crack propagation rate through a phenomenological relationship. The extremal peak amplitudes are shown by an ordered statistics treatment, to be extremally distributed. The statistical treatment enables the prediction of the number of cycles left until failure. Predictions performed a posteriori based on results gained early in each fatigue test are in good agreement with actual fatigue lives. Finally, the amplitude distribution analysis of the acoustic signals emitted during cyclic stress appears to be a promising nondestructive method of predicting fatigue life. 2: In this paper, low cycle high stress fatigue tests were conducted by tension-tension on an Alclad 7075-T6 aluminum sheet alloy, until rupture. Initial crack sizes and orientations in the fatigue specimens were randomly distributed. Acoustic emission was continuously monitored during the tests. Extremal peak-amplitudes, equivalent to extremal crack-propagation rates, are shown to be extremally Weibull distributed. The prediction of the number of cycles left until failure is made possible, using an ordered statistics treatment and an experimental equipment parameter obtained in previous experiments (Part 1). The predicted life-times are in good agreement with the actual fatigue lives. Finally, the amplitude distribution analysis of the acoustic signals emitted during cyclic stress has been proven to be a feasible nondestructive method of predicting fatigue life.

  1. Change of Hot Cracking Susceptibility in Welding of High Strength Aluminum Alloy AA 7075

    Science.gov (United States)

    Holzer, M.; Hofmann, K.; Mann, V.; Hugger, F.; Roth, S.; Schmidt, M.

    High strength aluminum alloys are known as hard to weld alloys due to their high hot crack susceptibility. However, they have high potential for applications in light weight constructions of automotive industry and therefore it is needed to increase weldability. One major issue is the high hot cracking susceptibility. Vaporization during laser beam welding leads to a change of concentration of the volatile elements magnesium and zinc. Hence, solidification range of the weld and therefore hot cracking susceptibility changes. Additionally, different welding velocities lead to changed solidification conditions with certain influence on hot cracking. This paper discusses the influence of energy per unit length during laser beam welding of AA 7075 on the change of element concentration in the weld seam and the resulting influence on hot cracking susceptibility. Therefore EDS-measurements of weld seams generated with different velocities are performed to determine the change of element concentration. These quantitative data is used to numerically calculate the solidification range in order to evaluate its influence on the hot cracking susceptibility. Besides that, relative hot crack length and mechanical properties are measured. The results increase knowledge about welding of high strength aluminum alloy AA 7075 and hence support further developing of the welding process.

  2. Influence of hydrogen content on the behavior of grain refinement in hypereutectic aluminum-silicon alloy

    Institute of Scientific and Technical Information of China (English)

    Lina Hu; Xiufang Bian; Youfeng Duan

    2004-01-01

    Dissolved hydrogen is harmful to mechanical properties of refined hypereutectic aluminum-silicon alloys. In the present work, by using a stepped-form mold and the hydrogen-detecting instrument HYSCAN Ⅱ, the relationship between the initial hydrogen content in the melt and the refinement effect on the casting of hypereutectic aluminum-silicon alloy was investigated. The experimental results show that the cooling rate, the hydrogen content and the grain refinement effect are three interactive factors. When the hydrogen content is above 0.20 mL/100 g and the cooling rate is lower than that in 50 mm-thick step, hydrogen dissolved in the alloy melt influences the grain refinement effect. With increasing the cooling rate, the critical hydrogen content increases too. It is expected that much hydrogen in the melt make the net interfacial energy larger than or equal to zero, resulting in the shielding of the particles AlP during solidification and that the critical gas content is closely related to the critical radius of embryo bubbles.

  3. Vertical Compensation Friction Stir Welding of 6061-T6 Aluminum Alloy

    Science.gov (United States)

    Ji, Shude; Meng, Xiangchen; Xing, Jingwei; Ma, Lin; Gao, Shuangsheng

    2016-09-01

    Vertical compensation friction stir welding (VCFSW) was proposed in order to solve the adverse effect caused by a big gap at the interface between two welded workpieces. VCFSW was successfully applied to weld 6061-T6 aluminum alloy with the thickness of 4 mm, while 2024-T4 aluminum alloy was selected as a rational compensation material. The results show that VCFSW is difficult to get a sound joint when the width of strip is no less than 1.5 mm. Decreasing the welding speed is beneficial to break compensation strip into pieces and then get higher quality joint. When the width of strip is 1 mm, the tensile strength and elongation of joint at the welding speed of 50 mm/min and rotational velocity of 1,800 rpm reach the maximum values of 203 MPa and 5.2%, respectively. Moreover, the addition of 2024-T4 alloy plays a strengthening effect on weld zone (WZ) of VCFSW joint. The fracture surface morphology of joint consisting of amounts of dimples exhibits ductile fracture.

  4. Separation of matrix alloy and reinforcement from aluminum metal matrix composites scrap by salt flux addition

    Indian Academy of Sciences (India)

    K R Ravi; R M Pillai; B C Pai; M Chakraborty

    2007-08-01

    Separation of matrix alloy and reinforcements from pure Al–SiCp composite scrap by salt flux addition has been theoretically predicted using interface free energies. Experiments performed confirm the theoretical prediction. Complete separation of matrix aluminum and reinforcement from metal matrix composites (MMCs) scrap has been achieved by addition of 2.05 wt% of equimolar mixture of NaCl–KCl salt flux with a metal and particle yield of 84 and 50%, respectively. By adding 5 wt% of NaF to equimolar mixture of NaCl–KCl, metal and particle yield improved to 91 and 73%, respectively. Reusability of both the matrix aluminum and the SiC separated from Al–SiCp scraps has been analysed using XRD, SEM and DTA techniques. The matrix alloy separated from Al–SiCp scraps can be used possibly as a low Si content Al–Si alloy. However, the interfacial reaction that occurred during the fabrication of the composites had degraded the SiC particles.

  5. 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.

  6. Synthetic sea water - An improved stress corrosion test medium for aluminum alloys

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1973-01-01

    A major problem in evaluating the stress corrosion cracking resistance of aluminum alloys by alternate immersion in 3.5 percent salt (NaCl) water is excessive pitting corrosion. Several methods were examined to eliminate this problem and to find an improved accelerated test medium. These included the addition of chromate inhibitors, surface treatment of specimens, and immersion in synthetic sea water. The results indicate that alternate immersion in synthetic sea water is a very promising stress corrosion test medium. Neither chromate inhibitors nor surface treatment (anodize and alodine) of the aluminum specimens improved the performance of alternate immersion in 3.5 percent salt water sufficiently to be classified as an effective stress corrosion test method.

  7. Laser Deep Penetration Welding of an Aluminum Alloy with Simultaneously Applied Vibrations

    Science.gov (United States)

    Woizeschke, Peer; Radel, Tim; Nicolay, Paul; Vollertsen, Frank

    2016-12-01

    In aluminum welding, the grain structure of produced seams is an essential factor with respect to the seam properties. In the casting technology the effect of mechanical vibrations on the grain growth during the solidification of liquid metals is known as a refinement method. In this paper, the transferability of this approach from comparatively long-time processes in the field of casting to the short-time process of laser deep penetration welding is investigated. Therefore, specimens were sinusoidal vibrated with frequencies up to 4 kHz during bead-on-plate full-penetration welding experiments. The resulting grain size was determined by applying the circular intercept procedure on the center of a cross-section micrograph of each weld. The results show that grain refinement is in general achievable by mechanical vibrations in the audible frequency range during laser full penetration keyhole welding of the aluminum alloy EN AW-5083.

  8. Formation of Aluminum-magnesium Alloy Cup by Hydrodynamic Deep Drawing with Twin-loading Paths

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaojing; XU Yongchao; YUAN Shijiang

    2009-01-01

    In order to overcome the limitation of hydro-rim deep drawing, a new process of hydrodynamic deep drawing (HDD) with independent radial hydraulic pressure was proposed. By employing the dynamic explicit analytical software ETA/Dynaform5.5 which is based onLS-DYNA3D, the effects of independent radial hydraulic pressure on the stress, strain and the sheet-thickness of aluminum-magnesium cylindrical cup with a hemispherical bottom were analyzed by numerical simulation. The feature of stress distribution is that there exists a stress-dividing circle in the flange, and the radius of dividing circle was determined by theoretical analysis and stimulation.The experimental results indicate that the reasonable match of independent radial hydraulic pressure and liquid chamber pressure can effectively reduce the thinning at the bottom of hemisphere, decrease the radial stress-strain, and improve the drawing limit of aluminum-magnesium alloy cylindrical cup.

  9. Microstructural and Hardness Study of Pulsed Nd:YAG Laser Surface Alloyed Aluminum with Iron

    Science.gov (United States)

    Ansari, Mohammad; Soltani, Reza; Heydarzadeh Sohi, Mahmoud; Valefi, Zia

    2016-04-01

    In the present study, the feasibility of the formation of surface layers containing hard iron aluminides on AA6061-T6 aluminum via pre-plasma spraying with iron and subsequently double surface melting by pulsed Nd:YAG laser is studied. The effects of single and double laser surface melting on microstructure, phase formation, and hardness of the treated layers are examined. Single-step laser treatment resulted in the presence of undissolved iron particles surrounded by lump-like Al5Fe2 and needle-like Al3Fe intermetallic compounds. Double laser surface melting dissolved the retained undissolved irons and resulted in the formation of Al-Al3Fe eutectic structure. Microhardness profiles along cross section and top surface of the treated layers indicated that laser surface alloying with iron enhanced the hardness of the aluminum to more than twice of that of the base material.

  10. Development of a melt foaming process with particulate reinforced aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Leitlmeier, D. [ARC Leichtmetellkompetenzzentrum Ranshofen GmbH, Ranshofen (Austria)]. E-mail: dietmar.leitlmeier@arcs.ac.at; Degischer, H.P. [Technische Universitat Wien, Wien (Austria)]. E-mail: sek308@pop.tuwien.ac.at; Babcsan, N. [Univ. of Misckolc, Dept. of Nonmetallic Material, Miskolc (Hungary)]. E-mail: femnorbi@gold.uni-miskolc.hu; Flankl, H.J. [Huette Klein Reichenbach, Schwarzenau (Austria)]. E-mail: hkb@aon.at

    2002-07-01

    This paper reports on investigations by Huette Klein-Reichenbach and LKR in the course of the development of a new processing technique for cellular aluminum, to produce net shape parts of foamed aluminum via the melt route by gas injection. The foaming depends on the interaction between the blowing gas, the ceramic particles and the melt. The stabilization of the foam by different particle contents in interaction with air, oxygen and nitrogen as blowing gas has been investigated for some matrix alloys with respect to the processing parameters. The resulting cell structure is characterized by computed X-ray tomography, light optical and scanning electron microscopy. The microstructure of the cell walls is presented as well as the achieved pore size and the local mass density distribution. (author)

  11. Thermal oxidation of the surface of binary aluminum alloys with rare-earth metals

    Science.gov (United States)

    Akashev, L. A.; Popov, N. A.; Kuznetsov, M. V.; Shevchenko, V. G.

    2015-05-01

    The kinetics of oxidation of the surface of Al alloys with 1-2.5 at % rare-earth metals (REMs) at 400-500°C in air was studied by ellipsometry and X-ray photoelectron spectroscopy (XPS). The addition (1-2.5 at % REM) of all rare-earth metals to aluminum was shown to increase the thickness of the oxide layer. The addition of surfactant and chemically active REMs (Yb, Sm, La, and Ce) increased the rate of oxidation of solid aluminum most effectively. The oxidation can be accelerated by the polymorphic transformations of the individual REM oxides in the film. The surface activity of Sm with respect to solid Al was confirmed by XRS.

  12. Improvement in the Mechanical Behavior of Mechanically Alloyed Aluminum Using Short-Time NH3 Flow

    Science.gov (United States)

    Caballero, E. S.; Cintas, J.; Cuevas, F. G.; Montes, J. M.; Herrera-García, M.

    2016-12-01

    In order to study the influence of a short-time ammonia gas flow during mechanical alloying (MA) of aluminum powders, samples were prepared using a simple press and sinter method. All milling experiments were performed at room temperature for a total of 10 hours. A short-time ammonia flow was incorporated into the milling process, allowing for the appearance of nitrogen-rich second phases, mainly oxycarbonitride and oxynitride aluminum (Al3CON and Al5O6N, respectively), during powder sintering. Testing of the sintering parts showed that the use of a short-time ammonia gas flow during vacuum milling substantially improved the mechanical properties at room and high temperatures.

  13. Effect of magnesium content on the semi solid cast microstructure of hypereutectic aluminum-silicon alloys

    Science.gov (United States)

    Hekmat-Ardakan, Alireza

    2009-12-01

    A comprehensive study of microstructural evolution of A390 hypereutectic aluminum-silicon alloy (Al-17%Si-4.5%Cu-0.5%Mg) with addition of Mg contents up to 10% was carried out during semi solid metal processing as well as conventional casting. As a first step, the FACTSAGE thermodynamic databank and software was applied in order to investigate the phase diagram, the solidification behavior as well as the identification of the components that are formed during the solidification of A390 alloy with different Mg contents for equilibrium and non-equilibrium (Schiel) conditions. With higher Mg content between 4.2 - 7.2 %, the Mg2Si intermetallic phase is solidified in the eutectic network according to the ternary reaction together the primary silicon due to the binary reaction of Liq → Si + Mg2Si. However the primary silicon is still the first solidified phase in this critical Mg zone. For Mg contents greater than 7.2%, the Mg2Si solidifies first as a primary phase. In fact, the Mg2Si is solidified during the primary, the binary and the ternary reactions and can be observed in the microstructure as a eutectic phase and a pro-eutectic phase with different morphology. In the next stage, the experimental tests were carried out in order to verify the accuracy of the results obtained by the FACTSAGE software. The microstructures of the A390 and the 6 and 10 wt% Mg alloys were investigated using conventional casting and rheocasting (stir casting) processes with continuous cooling solidification. The results showed that, for both processes, the microstructure of the eutectic network for high Mg alloys, specifically the eutectic Si phase is modified compared to the eutectic Si in the microstructure of A390 alloy. However the alloys with 6% and 10% Mg have a similar eutectic morphology. The eutectic formation temperature was measured by placing the thermocouple into the melt for determination of the cooling curves. DSC (Differential Scanning Calorimeter) test were also carried

  14. Vacuum brazing of electroless Ni-P alloy-coated SiCp/Al composites using aluminum-based filler metal foil

    Science.gov (United States)

    Wang, Peng; Xu, Dongxia; Niu, Jitai

    2016-12-01

    Using rapidly cooled (Al-10Si-20Cu-0.05Ce)-1Ti (wt%) foil as filler metal, the research obtained high-performance joints of electroless Ni-P alloy-coated aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process on joint properties and the formation of Al-Ni and Al-Cu-Ni intermetallic compounds were investigated, respectively. Due to the presence of Ni-P alloy coating, the wettability of liquid filler metal on the composites was improved obviously and its contact angle was only 21°. The formation of Al3Ni2 and Al3(CuNi)2 intermetallic compounds indicated that well metallurgical bonding occurred along the 6063Al matrix alloy/Ni-P alloy layer/filler metal foil interfaces by mutual diffusion and dissolution. And the joint shear strength increased with increasing the brazing temperature from 838 to 843 K or prolonging the soaking time from 15 to 35 min, while it decreased a lot because of corrosion occurring in the 6063Al matrix at high brazing temperature of 848 K. Sound joints with maximum shear strength of 112.5 MPa were obtained at 843 K for soaking time of 35 min. In this research, the beneficial effect of surface metallization by Ni-P alloy deposits on improving wettability on SiCp/Al-MMCs was demonstrated, and capable welding parameters were broadened as well.

  15. Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

    Energy Technology Data Exchange (ETDEWEB)

    Brachetti S, S. B. [Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo y Sor Juana I. de la Cruz, Col. Los Mangos, 89440 Ciudad Madero, Tanaulipas (Mexico); Dominguez C, M. A.; Torres H, A. M.; Onofre B, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Altamira, Carretera Tampico-Puerto Industrial Altamira Km. 14.5, 89600 Altamira, Tamaulipas (Mexico); De la Cruz H, W., E-mail: mdominguezc@ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 2681, 22800 Ensenada, Baja California (Mexico)

    2014-07-01

    The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO{sub 3}){sub 3} and La(NO{sub 3}){sub 3} solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

  16. Ultrasonic-assisted friction stir welding on V95AT1 (7075) aluminum alloy

    Science.gov (United States)

    Tarasov, S. Yu.; Rubtsov, V. Ye.; Kolubaev, E. A.; Ivanov, A. N.; Fortuna, S. V.; Eliseev, A. A.

    2015-10-01

    Ultrasonic-assisted friction stir butt welding on aluminum alloy V95AT1 (7075) has been carried out. Samples have been characterized using metallography, microhardness and XRD. As shown, ultrasonic treatment during welding provides extra plasticizing of metal and better stirring efficiency. The latter serves for elimination of defects, such as root flaw and grain refining in the stir zone. The stress state in the welded joint is characterized by tensile stress in the direction of the weld seam centerline and compression in the transversal direction. The ultrasonic treatment was shown to increase the compression stress and relieve the tensile one.

  17. Stress-Strain Compression of AA6082-T6 Aluminum Alloy at Room Temperature

    Directory of Open Access Journals (Sweden)

    Alexandre da Silva Scari

    2014-01-01

    Full Text Available Short cylindrical specimens made of AA6082-T6 aluminum alloy were studied experimentally (compression tests, analytically (normalized Cockcroft-Latham criteria—nCL, and numerically (finite element analysis—FEA. The mechanical properties were determined with the stress-strain curves by the Hollomon equation. The elastic modulus obtained experimentally differs from the real value, as expected, and it is also explained. Finite element (FE analysis was carried out with satisfactory correlation to the experimental results, as it differs about 1,5% from the damage analysis by the nCL concerning the experimental data obtained by compression tests.

  18. Tensile strength on friction stir processed AMg5 (5083) aluminum alloy

    Science.gov (United States)

    Chumaevsky, A. V.; Eliseev, A. A.; Filippov, A. V.; Rubtsov, V. E.; Tarasov, S. Yu.

    2016-11-01

    The results of the tensile tests carried out both on AMg5 (5083) aluminum alloy samples base and those obtained using friction stir processing technique are reported. The tensile test samples have been prepared from the friction stir processed plates so that their tensile axis was parallel to the processing direction. The maximum tensile strength of the processed samples was 9% higher than of the base metal. The fractographic examination shows the presence of flat areas inherent of the brittle fracture in all three friction processed samples. The load-extension curves show that friction stir processing may suppress the serrated yielding.

  19. Accelerated Near-Threshold Fatigue Crack Growth Behavior of an Aluminum Powder Metallurgy Alloy

    Science.gov (United States)

    Piascik, Robert S.; Newman, John A.

    2002-01-01

    Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low DK, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels of Kmax (Kmax less than 0.4 KIC). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and Kmax influenced accelerated crack growth is time and temperature dependent.

  20. Effect of cooling rate on microstructure of friction-stir welded AA1100 aluminum alloy

    Science.gov (United States)

    Yi, D.; Mironov, S.; Sato, Y. S.; Kokawa, H.

    2016-06-01

    In this work, the microstructural changes occurring during cooling of friction-stir welded aluminum alloy AA1100 were evaluated. To this end, friction-stir welding (FSW) was performed in a wide range of cooling rates of 20-62 K/s and the evolved microstructures were studied by using electron backscatter diffraction. Below 0.6 Tm (Tm being the melting point), the stir zone material was found to experience no significant changes during cooling. At higher FSW temperatures, however, notable changes occurred in the welded material, including grain growth, sharpening of texture, reduction of the fraction of high-angle boundaries and material softening.

  1. Radiographic detection of defects in friction stir welding on aluminum alloy AMg5M

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Sergei Yu., E-mail: tsy@ispms.ru; Kolubaev, Evgeny A., E-mail: eak@ispms.ru [National Research Tomsk Polytechnic University, Tomsk, 634050, Russia and Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Rubtsov, Valery E., E-mail: rvy@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2014-11-14

    In order to reveal weld defects specific to friction stir welding we undertook radiographic inspection of AMg5M aluminum alloy welded joints. Weld defects in the form of voids have been revealed in the weld obtained under the non-optimal rotation and feed rate. Both shape and size of these defects have been confirmed by examining metallographically successive sections prepared in the weld plane as well as in the plane transversal to the tool feed direction. Linear defects have been also found in the sections that are not seen in the radiographic images. Both the preferable localization and origination of the defects have been analyzed.

  2. STUDY ON THE HOT DEFORMATION BEHAVIORS OF Al-Zn-Mg-Cu-Cr ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    G.Y. Lin; Z.F. Zhang; H. Zhang; D.S. Peng; J. Zhou

    2008-01-01

    The hot deformation behaviors and mierostructures of Al-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress versus true strain curves and the microstructures under various deformation conditions are obtained. The microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates. The quantitative relationship between the Zener-HoUomon parameter (Z) and average recrystallization grain size in the subsequent heat treatment is set up.

  3. Performance Comparison of Steam-Based and Chromate Conversion Coatings on Aluminum Alloy 6060

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    In this study, oxide layers generated on aluminum alloy 6060(UNS A96060) using a steam-based process were compared with conventional chromate and chromate-phosphate conversion coatings. Chemical composition and microstructure of the conversion coatings were investigated and their corrosion...... performance was evaluated using potentio dynamic polarization, acetic acid salt spray, and filiform corrosion testing of powder coated specimens. The steam-based process resulted in homogenous growth of oxide layer and superior coverageover intermetallic particles when compared to chromate-based conversion...... coatings. The coating formed by steam showed improved corrosion resistance, while adhesion to powder coatingand filiform corrosion was comparable with chromate conversion coatings....

  4. Analysis of the cyclic behavior and fatigue damage of extruded AA2017 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    May, A., E-mail: abdelghani1980@yahoo.fr [INSA/GPM, CNRS UMR 6634, BP 08 avenue de l' université, 76801 Saint Etienne du Rouvray Cedex (France); Laboratoire Génie des Matériaux, Ecole Militaire Polytechnique, BP 17 Bordj El-Bahri Algiers (Algeria); Taleb, L., E-mail: lakhdar.taleb@insa-rouen.fr [INSA/GPM, CNRS UMR 6634, BP 08 avenue de l' université, 76801 Saint Etienne du Rouvray Cedex (France); Belouchrani, M.A., E-mail: nbelouch@yahoo.fr [Laboratoire Génie des Matériaux, Ecole Militaire Polytechnique, BP 17 Bordj El-Bahri Algiers (Algeria)

    2013-06-01

    The present work is devoted to study the anisotropic behavior of an extruded aluminum alloy under cyclic loading in axial and shear directions. In first, we have studied its elastoplastic behavior through the evolution of stress–strain loops, isotropic and kinematic hardening and we have associated this behavior with the evolution of its elastic adaptation (shakedown). In second, we have studied the behavior of the material in fatigue damage using the evolution of stiffness. Finally, microstructural investigations were performed on fractured surfaces using scanning electron microscope (SEM) in order to understand the evolution of fatigue damage during cyclic loading.

  5. Study on the Predicting System of Breaking Chip When PCD Tool Cutting Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the field of automobile manufacture, during the aluminum alloy cutting, chip forming and breaking process are very complicated. It is affected by many facto rs. Automatic machining process can not be carried through if the chip enlaces t he workpiece or the tool. So the chip control and breaking are key technology. P CD tool has many traits, such as high cutting efficiency, machining precision an d wearability. It is desired that it be used for machining coloured metals.The p aper present the study of p...

  6. Optimized constitutive equation of material property based on inverse modeling for aluminum alloy hydroforming simulation

    Institute of Scientific and Technical Information of China (English)

    LANG Li-hui; LI Tao; ZHOU Xian-bin; B. E. KRISTENSEN; J. DANCKERT; K. B. NIELSEN

    2006-01-01

    By using aluminum alloys, the properties of the material in sheet hydroforming were obtained based on the identification of parameters for constitutive models by inverse modeling in which the friction coefficients were also considered in 2D and 3D simulations. With consideration of identified simulation parameters by inverse modeling, some key process parameters including tool dimensions and pre-bulging on the forming processes in sheet hydroforming were investigated and optimized. Based on the optimized parameters, the sheet hydroforming process can be analyzed more accurately to improve the robust design. It proves that the results from simulation based on the identified parameters are in good agreement with those from experiments.

  7. Properties of a Retrogressed and Re-Aged 7075 Aluminum Alloy.

    Science.gov (United States)

    1984-12-31

    Kerlins, & B. V. Whitenson, " Electon Fractograph Hand Book ", Air Fore Materials Lab. Report No. ML-T-DR-64-418, 1965. (w) Awrosoce SN~dOO&W Metals... Engineering and Applied Sclince. Contract No. N0001 4-81 -K--0292, May, 1962. (a) J. M. Papplaon: "Effect of Two-Stage Aging on Microstructure of 7075...Method of Test for Exfoliation Corrosion Susceptibilty In 7 Swries Copper Containi ng Aluminum Alloys (EXCO test). 1979 Annual Book of ASTM

  8. Effect of Low Frequency Electromagnetic Field on Macrosegregation of Horizontal Direct Chill Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhihao ZHAO; Jianzhong CUI; Jie DONG; Beijiang ZHANG

    2005-01-01

    The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequency electromagnetic field has been applied in HDC casting process and the relevant influence has been studied. The results show that application of low frequency electromagnetic field can reduce macrosegregation in HDC casting process; and two main parameters of electromagnetic field density and frequency, have great influences on the solution distribution along the diameter of ingot. Moreover, the mechanisms of reduction of macrosegregation by electromagnetic field have been discussed.

  9. Laser Beam Welding of Aluminum Alloys Under the Influence of an Electromagnetic Field

    Science.gov (United States)

    Schneider, A.; Avilov, V.; Gumenyuk, A.; Rethmeier, M.

    During laser beam welding of aluminum alloys an electromagnetic field may favour pore outgassing through the top oxide layer. High frequencies cause a small penetration depth and thus exert a stabilizing effect on the weld surface. The point at which the laser beam between the two magnetic poles hits the workpiece surface is crucial to the influence of the magnetic field on the weld surface roughness. Using analyzed parameters for different laser points of application cause a change in weld surface roughness could be observed. The weld surface roughness could be reduced by 50%. The outgassing effect in terms of a reduction of pores could be observed for all parameter sets investigated.

  10. Fabrication of Unidirectional Fiber Reinforced 6061 Aluminum Alloy Using High Pressure Squeeze Casting

    Science.gov (United States)

    1988-12-01

    soiidfication front as a funct:on of t:me. Suoerim csea cni t2s ine are ooin:s tlat reoresent t",e exact solution at the corresoonaing t:mes as cotainea from the...Bomoay, (1981). Nomoto, M., "Mechanical Properties of Squeeze Castings in Al- Cu Alloys," Journal Japan Institute Light Metals, Vol. 30 (1980), pp 212-216...5. KaneKo, Y., Murakami, H., Kuroda, K. and Nagazaki, S., "Squeeze Casting of Aluminum," Foundry Trade Journal , Vol. 148 (1980), pp 397-411. 6

  11. The influence of the parameters of lost foam process on the quality of aluminum alloys castings

    Directory of Open Access Journals (Sweden)

    Aćimović-Pavlović Zagorka

    2010-01-01

    Full Text Available This paper presents the research results of application of Lost foam process for aluminum alloys castings of a simple geometry. The process characteristic is that patterns and gating of moulds, made of polymers, stay in the mould till the liquid metal inflow. In contact with the liquid metal, pattern intensely and in relatively short time decomposes and evaporates, which is accompanied by casting crystallization. As a consequence of polymer pattern decomposition and evaporation a great quantity of liquid and gaseous products are produced, which is often the cause of different types of casting errors. This paper presents the results of a research with a special consideration given to detecting and analyzing the errors of castings. In most cases the cause of these errors are defects of polymer materials used for evaporable patterns production, as well as defects of materials for refractory coatings production for polymer patterns. The researches have shown that different types of coatings determine properties of the obtained castings. Also, the critical processing parameters (polymer pattern density, casting temperature, permeability of refractory coating and sand, construction of patterns and gating of moulds significantly affect on castings quality. During the research a special consideration was given to control and optimization of these parameters with the goal of achieving applicable castings properties. The study of surface and internal error of castings was performed systematically in order to carry out preventive measures to avoid errors and minimize production costs. In order to achieve qualitative and profitable castings production by the method of Lost foam it is necessary to reach the balance in the system: evaporable polymer pattern - liquid metal - refractory coating - sandy cast in the phase of metal inflow, decomposition and evaporation of polymer pattern, formation and solidification of castings. By optimizing the processing

  12. Analysis of porosity characteristics in weld metal of high strength aluminum alloy and the effect of mixed shielding gas

    Energy Technology Data Exchange (ETDEWEB)

    Xiaomu Zhang; Zhiyong Zhang; Yun Peng; Zhiling Tian; Changhong He; Hongjun Xiao; Chengyong Ma [Central Iron and Steel Research Inst., Beijing, BJ (China)

    2005-07-01

    Aluminum alloy has being widely used in modern automobile and aeronautic industry. However, the welding of aluminum alloy, especially high strength aluminum alloy is difficult. Porosities are usually brought in the weld metal. In this paper, MIG welding using mixed gas shielding is carried out. The characteristic shapes of porosity in weld metal are described, the mechanism of porosity formation is analyzed, and the factors that influence the tendency of porosity formation are studied. Experiment results indicate that by the use of mixed shielding gas of 38%He+62%Ar, the number of porosity is reduced, the width of HAZ and softened zone is decreased, and the mechanical properties of welded joint is increased. (orig.)

  13. Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Kalemba I.

    2015-06-01

    Full Text Available The long term natural aging behavior of friction stir welded aluminum 7136-T76 and 7042 T6 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles for the 7136 alloy taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The hardness profile for the 7042 alloy displayed U-shape in the as-welded condition and W-shape after natural aging. The hardness behavior upon natural aging correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone.

  14. Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting

    Directory of Open Access Journals (Sweden)

    Juliana de Paula Martins

    2012-02-01

    Full Text Available A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1 to reduce the strip's thickness by 67%, and 2 to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001} component, predominated in the as-cast condition and was transformed into brass, copper and S type textures during the cold rolling process. There was practically no difference between the deformation textures at the two thickness reductions.

  15. Structural and electrical properties of copper-nickel-aluminum alloys obtained by conventional powder metallurgy method

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Waldemar A.; Carrio, Juan A.G.; Silveira, C.R. da; Pertile, H.K.S., E-mail: fisica.cch@mackenzie.br [Universidade Presbiteriana Mackenzie (UPM/CCH), Sao Paulo, SP (Brazil). Centro de Ciencias e Humanidades. Dept. de Fisica; Silva, L.C.E. da; Buso, S.J., E-mail: jgcarrio@mackenzie.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    This work looked for to search out systematically, in scale of laboratory, copper-nickel-aluminum alloys (Cu-Ni-Al) with conventional powder metallurgy processing, in view of the maintenance of the electric and mechanical properties with the intention of getting electric connectors of high performance or high mechanical damping. After cold uniaxial pressing (1000 kPa), sintering (780 deg C) and convenient homogenization treatments (500 deg C for different times) under vacuum (powder metallurgy), the obtained Cu-Ni-Al alloys were characterized by optical microscopy, electrical conductivity, Vickers hardness. X rays powder diffraction data were collected for the sintered samples in order to a structural and microstructural analysis. The comparative analysis is based on the sintered density, hardness, macrostructures and microstructures of the samples. (author)

  16. Al-Si-Mn Alloy Coating on Aluminum Substrate Using Cold Metal Transfer (CMT) Welding Technique

    Science.gov (United States)

    Rajeev, G. P.; Kamaraj, M.; Bakshi, S. R.

    2014-06-01

    The cold metal transfer (CMT) process was explored as a weld overlay technique for synthesizing Al-Si-Mn alloy coating on a commercially pure Al plate. The effect of welding speed on the bead geometry, deposition rate, and the dilution were studied and the best parameter was used to synthesize the coatings. The CMT process can be used to produce thick coatings (>2.5 mm) without porosity and with low dilution levels. The Vickers hardness number of the Al substrate increased from 28 in the bulk to 57 in the coating. It is suggested that the CMT process can be an effective and energy-efficient technique for depositing thick coatings and is useful in weld repair of aluminum alloy components.

  17. Experiments and FEM simulations of fracture behaviors for ADC12 aluminum alloy under impact load

    Science.gov (United States)

    Hu, Yumei; Xiao, Yue; Jin, Xiaoqing; Zheng, Haoran; Zhou, Yinge; Shao, Jinhua

    2016-11-01

    Using the combination of experiment and simulation, the fracture behavior of the brittle metal named ADC12 aluminum alloy was studied. Five typical experiments were carried out on this material, with responding data collected on different stress states and dynamic strain rates. Fractographs revealed that the morphologies of fractured specimen under several rates showed different results, indicating that the fracture was predominantly a brittle one in nature. Simulations of the fracture processes of those specimens were conducted by Finite Element Method, whilst consistency was observed between simulations and experiments. In simulation, the Johnson- Cook model was chosen to describe the damage development and to predict the failure using parameters determined from those experimental data. Subsequently, an ADC12 engine mount bracket crashing simulation was conducted and the results indicated good agreement with the experiments. The accordance showed that our research can provide an accurate description for the deforming and fracture processes of the studied alloy.

  18. Modeling of radiation-induced sink evolution in 6061 aluminum alloy in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Il; Kim, Ji Hyun [Department of Nuclear Science and Engineering, School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of); Lee, Gyeong-Geun; Kwon, Junhyun [Division of Nuclear Materials Research, Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of)

    2016-11-15

    The objective of this study is a detailed analysis of the radiation effects on sink generation and growth in order to understand the phenomenon of irradiation hardening of 6061 aluminum alloy in research reactor conditions. In order to have a fundamental understanding, various sink behavior characteristics such as size and number density of dislocation loop, void, and precipitation were calculated and examined. Thereafter, theoretical assessment of various sink effects on irradiation hardening was conducted based on the mean field rate theory (MFRT). Dislocation loop, void, and precipitation were examined by defect flux. For the quantitative analysis of radiation-induced degradation, change in sink size was calculated using number density. 6061 Alloy showed great dependence on precipitation generation and growth. However, dislocation loop and void did not have any significant effect on irradiation hardening. Finally, the behavior of sinks was compared with the experimental results for validation. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Structure and properties of ceramic coatings formed on aluminum alloys by microarc oxidation

    Institute of Scientific and Technical Information of China (English)

    LIU Wan-hui; BAO Ai-lian; LIU Rong-xiang; WU Wan-liang

    2006-01-01

    The thick and hard ceramic coatings were deposited on 2024 Al alloy by microarc oxidation in the electrolytic solution.Microstructure, phase composition and wear resistance of the oxide coatings were investigated by SEM, XRD and friction and wear tester. The microhardness and thickness of the oxide coatings were measured. The results show that the ceramic coating is mainly composed of α-Al2O3 and γ-Al2O3. During oxidation, the temperature in the microarc discharge channel is very high to make the local coating molten. From the surface to interior of the coating, microhardness increases gradually. The microhardness of the ceramic coating is HV1 800, and the microarc oxidation coatings greatly improve the antiwear properties of aluminum alloys.

  20. Novel accelerated corrosion test for LY12CZ and LC4CS aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    CAI Jian-ping; LIU Ming

    2006-01-01

    A new accelerated corrosion test-comprehensive environmental test (CET) was developed in order to estimate the outdoor corrosion of aluminum alloys in marine environment. The environmental characteristics in CET were studied by atmospheric corrosion monitor (ACM), and the morphology of corrosion product was observed by SEM. The correlation between the accelerated corrosion tests and outdoor exposure was discussed. The results show that the anti-corrosion ranking for LY12CZ, LC4CS, clad LY12CZ, and clad LC4CS in CET is the same as that of the alloys exposed outdoor, and ACM study shows that CET demonstrates the same environmental characteristics as that exposed outdoor. CET is a more accurate accelerated corrosion test, and a mathematical relation was obtained to describe the relation between CET and outdoor test.

  1. Primary and secondary creep in aluminum alloys as a solid state transformation

    Science.gov (United States)

    Fernández, R.; Bruno, G.; González-Doncel, G.

    2016-08-01

    Despite the massive literature and the efforts devoted to understand the creep behavior of aluminum alloys, a full description of this phenomenon on the basis of microstructural parameters and experimental conditions is, at present, still missing. The analysis of creep is typically carried out in terms of the so-called steady or secondary creep regime. The present work offers an alternative view of the creep behavior based on the Orowan dislocation dynamics. Our approach considers primary and secondary creep together as solid state isothermal transformations, similar to recrystallization or precipitation phenomena. In this frame, it is shown that the Johnson-Mehl-Avrami-Kolmogorov equation, typically used to analyze these transformations, can also be employed to explain creep deformation. The description is fully compatible with present (empirical) models of steady state creep. We used creep curves of commercially pure Al and ingot AA6061 alloy at different temperatures and stresses to validate the proposed model.

  2. Detecting sensitization in aluminum alloys using acoustic resonance and EMAT ultrasound

    Science.gov (United States)

    Cobb, Adam; Macha, Erica; Bartlett, Jonathan; Xia, Yanquan

    2017-02-01

    Sensitization of 5xxx series aluminum alloys is characterized by the gradual precipitation of the alloying element magnesium as a beta phase (Al3Mg2) along the grain boundaries after prolonged exposure to the environment. While the 5xxx alloy is corrosion resistant, these beta phases are corrosive and thus their formation increases the susceptibility of the alloy to intergranular corrosion and stress corrosion cracking. The standardized approach for measuring the degree of sensitization (DoS) is the ASTM G67 test standard. This test, however, is time consuming, difficult to perform, and destructive, as it involves measurement of a mass loss after exposing the alloy to a nitric acid solution. Given the limitations of this test standard, there is a need to develop a nondestructive evaluation (NDE) solution that is easy-to-use, non-intrusive, and faster than current inspection methods while suitable for use outside a laboratory. This paper describes the development of an NDE method for quantifying the DoS value in an alloy using ultrasonic measurements. The work builds upon prior efforts described in the literature that use electromagnetic acoustic transducers (EMATs) to quantify DoS based on velocity measurements. The prior approaches used conventional ultrasonic inspection techniques with short-duration excitation signals (less than 3 cycles) to allow identification of the echo time-of-flight and amplitude decay pattern, but their success was limited by EMAT transducer inefficiency in general, especially at higher frequencies. To overcome these challenges, this paper presents a modified ultrasonic measurement strategy using long-duration excitation signals (greater than 100 cycles), where multiple reverberations in the material overlap. By sweeping through test frequencies, it is possible to establish an acoustic resonance when the wavelength is an integer multiple of twice the material thickness. This approach allows for greatly improved signal to noise ratios as

  3. Theoretical simulation of melt ejection during the laser drilling process on aluminum alloy by single pulsed laser

    Science.gov (United States)

    Li, Mingxin; Jin, Guangyong; Guo, Ming; Wang, Di; Gu, Xiuying

    2014-12-01

    In this paper, we establish a physical model to simulate the melt ejection induced by millisecond pulsed laser on aluminum alloy and use the finite element method to simulate the melting and vaporization process of aluminum alloy. Compared with the conventional model, this model explicitly adds the source terms of gas dynamics in the thermal-hydrodynamic equations, completes the trace of the gas-liquid interface and improves the traditional level-set method. All possible effects which can impact the dynamic behavior of the keyhole are taken into account in this two-dimensional model, containing gravity, recoil pressure of the metallic vapor, surface tension and Marangoni effect. This simulation is based on the same experiment condition where single pulsed laser with 3ms pulse width, 57J energy and 1mm spot radius is used. By comparing the theoretical simulation data and the actual test data, we discover that: the relative error between the theoretical values and the actual values is about 9.8%, the melt ejection model is well consistent with the actual experiment; from the theoretical model we can see the surrounding air of the aluminum alloy surface exist the metallic vapor; an increment of the interaction time between millisecond pulsed laser and aluminum alloy material, the temperature at the center of aluminum alloy surface increases and evaporation happens after the surface temperature reaches boiling point and later the aluminum alloy material sustains in the status of equilibrium vaporization; the keyhole depth is linearly increased with the increase of laser energy, respectively; the growth of the keyhole radius is in the trend to be gentle. This research may provide the theoretical references to the understanding of the interaction between millisecond pulsed laser and many kinds of materials, as well as be beneficial to the application of the laser materials processing and military field.

  4. Localized Corrosion Behavior of Al-Si-Mg Alloys Used for Fabrication of Aluminum Matrix Composites

    Science.gov (United States)

    Pech-Canul, M. A.; Giridharagopal, R.; Pech-Canul, M. I.; Coral-Escobar, E. E.

    2013-12-01

    The relationship between microstructure and localized corrosion behavior in neutral aerated chloride solutions was investigated with SEM/EDAX, conventional electrochemical techniques, and with scanning Kelvin probe force microscopy (SKPFM) for two custom-made alloys with Si/Mg molar ratios of 0.12 and 0.49. In this order, Al3Fe, Al3Mg2, and Mg2Si intermetallics were identified in the first alloy and Al(FeMn)Si and Mg2Si particles in the second one. Anodic polarization curves and corrosion morphology showed that the alloy with higher Si/Mg molar ratio exhibited a better corrosion performance and evidence was shown that it had a more corrosion-resistant passive film. The corrosion process for both alloys in aerated 0.1 M NaCl solutions was localized around the Fe-rich intermetallics. They acted as local cathodes and produced dissolution of the aluminum matrix surrounding such particles. Mg2Si and Al3Mg2 exhibited anodic behavior. SKPFM was successfully used to map the Volta potential distribution of main intermetallics. The localized corrosion behavior was correlated with a large Volta potential difference between the Fe-rich intermetallics and the matrix. After immersion in the chloride solution, such Volta potential difference decreased.

  5. Microstructure and mechanical properties of Gd-modified A356 aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    史志铭; 王强; 史玉亭; 赵鸽; 张瑞英

    2015-01-01

    The effect of Gd modification on the microstructure and mechanical properties of A356 aluminum alloys was investigated using the metallurgical microscopy, scanning electronic microscopy, X-ray diffraction and mechanical testing. The addition of 0.2 wt.%–0.4 wt.%Gd had an excellent refining effect on primaryα-Al grains and a modification effect on Si phases in its as-cast state. The needle-like Si phases were adjusted into fine particles and uniformly distributed in the matrix by the T6 treatment, especially for the 0.2 wt.% Gd-modified alloy. The Gd additions introduced the Fe-containing GdAl2Si2 compounds, which precipitated in the forms of flakes and bulks. The GdAl2Si2 andβ-Al5FeSi phases were also refined by the T6 treatment. The mechanical properties of the Gd-modified alloys were very poor in as-cast state;however, the highest strength and elongation were obtained for the 0.2 wt.%Gd-modified alloy by the T6 treatment.

  6. EFFECT OF CASTING MOULD ON MECHANICAL PROPERTIES OF 6063 ALUMINUM ALLOY

    Directory of Open Access Journals (Sweden)

    WASIU AJIBOLA AYOOLA

    2012-02-01

    Full Text Available Modern production methods for casting articles include the use of sand- mould, metal-mould, die, and centrifugal castings. Castings produced using sand mould is known to have peculiar microstructures depending on average size, distribution and shape of the moulding sand grains and the chemical composition of the alloy. These affect the surface finish, permeability and refractoriness of all the castings. In this paper, the effect of using CO2 process, metal mould, cement-bonded sand mould and naturally-bonded sand mould on the hardness, tensile and impact strengths of as-cast 6063 Aluminum alloy is presented. The results show that there is significant increase in hardness(33.7 HB of the alloy when naturally-bonded sand mould is used for its production over that of metal, CO2 and cement moulds. The stress-strain curves behaviour of the samples also indicated that sample from naturally bonded sand has highest tensile strength with superior ductility. The alloy shows highest impact strength when metal mould is used for sample preparation in comparison with other moulds.

  7. Microstructure Analysis of Directionally Solidified Aluminum Alloy Aboard the International Space Station

    Science.gov (United States)

    Angart, Samuel Gilbert

    This thesis entails a detailed microstructure analysis of directionally solidified (DS) Al-7Si alloys processed in microgravity aboard the International Space Station and similar duplicate ground based experiments at Cleveland State University. In recent years, the European Space Agency (ESA) has conducted experiments on alloy solidification in microgravity. NASA and ESA have collaborated for three DS experiments with Al- 7 wt. % Si alloy, aboard the International Space Station (ISS) denoted as MICAST6, MICAST7 and MICAST12. The first two experiments were processed on the ISS in 2009 and 2010. MICAST12 was processed aboard the ISS in the spring of 2014; the resulting experimental results of MICAST12 are not discussed in this thesis. The primary goal of the thesis was to understand the effect of convection in primary dendrite arm spacings (PDAS) and radial macrosegregation within DS aluminum alloys. The MICAST experiments were processed with various solidification speeds and thermal gradients to produce alloy with differences in microstructure features. PDAS and radial macrosegregation were measured in the solidified ingot that developed during the transition from one solidification speed to another. To represent PDAS in DS alloy in the presence of no convection, the Hunt-Lu model was used to represent diffusion-controlled growth. By sectioning cross-sections throughout the entire length of solidified samples, PDAS was measured and calculated. The ground-based (1-g) experiments done at Cleveland State University CSU were also analyzed for comparison to the ISS experiments (0-g). During steady state in the microgravity environment, there was a reasonable agreement between the measured and calculated PDAS. In ground-based experiments, transverse sections exhibited obvious radial macrosegregation caused by thermosolutal convection resulting in a non-agreement with the Hunt-Lu model. Using a combination of image processing techniques and Electron Microprobe Analysis

  8. Mechanical properties of the A356 aluminum alloy modified with La/Ce

    Institute of Scientific and Technical Information of China (English)

    E. Aguirre-De la Torre; R. Pérez-Bustamante; J. Camarillo-Cisneros; C.D. Gómez-Esparza; H.M. Medrano-Prieto; R. Martínez-Sánchez

    2013-01-01

    The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstructure of the automotive A356 aluminum alloy reinforced with 0.2 (wt.%) Al-6Ce-3La (ACL) was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results ob-tained from the A356 alloy strengthened with ACL in the as-received condition. Microstructural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the Al matrix. In addition, electron microscopy was employed in or-der to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens after solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes;however, mechanical results, in the modified A356 alloy with the ACL in the as-received condi-tion, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled.

  9. Property of anodic coatings obtained in an organic, environmental friendly electrolyte on aluminum alloy 2024-T3

    Science.gov (United States)

    Zhang, R. F.; Shi, H. W.; Liu, Z. L.; Zhang, S. F.; Zhang, Y. Q.; Guo, S. B.

    2014-01-01

    Anodic coatings were obtained by micro arc oxidation on aluminum alloy 2024-T3 in a solution containing only 10 g/L sodium phytate. The morphology, composition, structure and corrosion resistance of anodic coatings were systematically investigated. The results show that the working voltage continually increases during 3 min and bright sparks appear after 25 s. Anodic coatings are evenly formed on the substrate and about 2 μm thick. XPS and XRD analyses reveal that the obtained coatings are mainly composed of α-Al2O3 and γ-Al2O3. Compared with the substrate, the corrosion resistance of the anodized aluminum alloys is improved.

  10. Liquid oxygen LOX compatibility evaluations of aluminum lithium (Al-Li) alloys: Investigation of the Alcoa 2090 and MMC weldalite 049 alloys

    Science.gov (United States)

    Diwan, Ravinder M.

    1989-01-01

    The behavior of liquid oxygen (LOX) compatibility of aluminum lithium (Al-Li) alloys is investigated. Alloy systems of Alcoa 2090, vintages 1 to 3, and of Martin Marietta Corporation (MMC) Weldalite 049 were evaluated for their behavior related to the LOX compatibility employing liquid oxygen impact test conditions under ambient pressures and up to 1000 psi. The developments of these aluminum lithium alloys are of critical and significant interest because of their lower densities and higher specific strengths and improved mechanical properties at cryogenic temperatures. Of the different LOX impact tests carried out at the Marshall Space Flight Center (MSFC), it is seen that in certain test conditions at higher pressures, not all Al-Li alloys are LOX compatible. In case of any reactivity, it appears that lithium makes the material more sensitive at grain boundaries due to microstructural inhomogeneities and associated precipitate free zones (PFZ). The objectives were to identify and rationalize the microstructural mechanisms that could be relaxed to LOX compatibility behavior of the alloy system in consideration. The LOX compatibility behavior of Al-Li 2090 and Weldalite 049 is analyzed in detail using microstructural characterization techniques with light optical metallography, scanning electron microscopy (SEM), electron microprobe analysis, and surface studies using secondary ion mass spectrometry (SIMS), electron spectroscopy in chemical analysis (ESCA) and Auger electron spectroscopy (AES). Differences in the behavior of these aluminum lithium alloys are assessed and related to their chemistry, heat treatment conditions, and microstructural effects.

  11. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft

    Science.gov (United States)

    Starke, E. A., Jr.

    1997-01-01

    This is the final report of the study "Aluminum-Based Materials for High Speed Aircraft" which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX without Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys, and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  12. Research progress on microstructure evolution of semi-solid aluminum alloys in ultrasonic ifeld and their rheocasting

    Institute of Scientific and Technical Information of China (English)

    Wu Shusen; Lin Chong; Lü Shulin; Sha Meng

    2014-01-01

    The effects of ultrasonic vibration (UV) treatment on microstructure of semi-solid aluminum alloys and the application of UV in rheocasting process are reviewed. Good semi-solid slurry can be produced by high-intensity UV process for aluminum alloys. The microstructures of Al-Si, Al-Mg and Al-Cu aloys produced by rheocasting assisted with UV are compact and with fine grains. The mechanical properties of the UV treated alloys are increased by about 20%-30%. Grain refinement of the alloys is generally considered because of cavitation and acoustic streaming caused by UV. Apart from these mechanisms, a hypothesis of the fuse of dendrite root caused by capillary infiltration in the ultrasonic field, as well as a mechanism of crystalites faling off from the mould-wal and crystal multiplication by mechanical vibration effect in indirect ultrasonic vibration are proposed to explain the microstructure evolution of the aloys.

  13. Effect of heat diffusion on properties of zinc-aluminum coating on AZ91D magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    LI Zhao-feng; HUANG Wei-jiu; LIU Ming

    2006-01-01

    A protecting zinc and aluminum coating on the surface of AZ91D magnesium alloys was obtained by thermal spraying to improve the corrosion and wear resistance performances. In order to enhance the combination between magnesium alloy matrix and zinc and aluminum coating, the sample was heat-treated at 300 ℃ for 2 h, then, the cross-section patterns, XRD pattern, micro-hardness, wear and corrosion resistance abilities were researched. The results indicate that the interface between the coating and substrate is metallurgical bond, and a transitional fusion layer is formed by diffusion. The micro-scale abrasion test and polarization test in 3% NaCl solution show that the diffusion-treated specimen has better wear and corrosion resistance performances in comparison with the undiffusion-treated and substrate magnesium alloys; in addition, it has relatively higher micro-hardness than the undiffusion-treated magnesium alloys.

  14. 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.

  15. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Elevated Temperature Aluminum Metal Matrix Composite (MMC) Alloy and Its Processing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, David C. [Eck Industreis, Inc.; Gegal, Gerald A.

    2014-04-15

    The objective of this project was to provide a production capable cast aluminum metal matrix composite (MMC) alloy with an operating temperature capability of 250-300°C. Important industrial sectors as well as the military now seek lightweight aluminum alloy castings that can operate in temperature ranges of 250-300°C. Current needs in this temperature range are being satisfied by the use of titanium alloy castings. These have the desired strength properties but the end components are heavier and significantly more costly. Also, the energy requirements for production of titanium alloy castings are significantly higher than those required for production of aluminum alloys and aluminum alloy castings.

  16. Utility of magneto-electropolished ternary nitinol alloys for blood contacting applications.

    Science.gov (United States)

    Pulletikurthi, Chandan; Munroe, Norman; Stewart, Danique; Haider, Waseem; Amruthaluri, Sushma; Rokicki, Ryszard; Dugrot, Manuel; Ramaswamy, Sharan

    2015-10-01

    The thrombogenicity of a biomaterial is mainly dependent on its surface characteristics, which dictates its interactions with blood. Surface properties such as composition, roughness wettability, surface free energy, and morphology will affect an implant material's hemocompatibility. Additionally, in the realm of metallic biomaterials, the specific composition of the alloy and its surface treatment are important factors that will affect the surface properties. The utility of magneto-electropolished (MEP) ternary Nitinol alloys, NiTiTa, and NiTiCr as blood contacting materials was investigated. The hemcompatibility of these alloys were compared to mechanically polished (MP) metallic biomaterial counterparts. In vitro thrombogenicity tests revealed significantly less platelet adherence on ternary MEP Nitinol, especially MEP NiTi10Ta as compared to the MP metals (p Nitinol alloys can potentially be utilized for blood-contacting devices where, complications resulting from thrombogenicity can be minimized.

  17. Frictional behaviors of some nitrogen ceramics in conformal contact with tin coated Al-Si alloy, steel and MMC

    Science.gov (United States)

    Wang, Q.; Cheng, H. S.; Fine, M. E.

    1994-07-01

    The frictional behavior of certain nitrogen-containing ceramics, such as silicon nitride, alpha sialons, and beta sialons as journal materials were studied in conformal contact with a tin-coated Al-Si alloy (Al-Si/Sn), forged 1141 steel and a cast aluminum matrix composite with silicon carbide reinforcement (cast metal matrix composites (MMC)) as bearing materials while lubricated with SAE 10W30. A case-hardened 1016 steel was also tested with the Al-Si/Sn and cast MMC bearings under the same conditions. The friction values of the ceramic and the steel journal wear pairs were compared and their frictional behaviors were evaluated. Silicon nitride and one of the beta sialons exhibited higher load-supporting capacities than the others when they were in contact with the 1141 steel bearings. The journal surface roughness was found to be very important when the journals were in contact with the Al-Si/Sn bearings. The frictional behavior of the ceramics and cast MMC pairs and the steel and cast MMC pairs were controlled by different wear machanisms, namely for the former, hard particle pull-out and matrix plowing, and for the latter, iron transfer from the journal to the cast MMC bearing surface.

  18. Embedded Shape Memory Alloy Particles for the Self-Sensing of Fatigue Crack Growth in an Aluminum Alloy

    Science.gov (United States)

    Leser, William Paul

    Future aerospace vehicles will be built using novel materials for mission conditions that are difficult to replicate in a laboratory. Structural health monitoring and condition-based maintenance will be critical to ensure the reliability of such vehicles. A multi-functional aluminum alloy containing embedded shape memory alloy (SMA) particles to detect fatigue crack growth is proposed. The regions of intensified strain near the tip of a growing fatigue crack cause the SMA particles to undergo a solid-to-solid phase transformation from austenite to martensite, releasing a detectable and identifiable acoustic emission (AE) signal that can be used to locate the crack in the affected component. This study investigates the AE response of two SMA systems, Ni-Ti, and Co-Ni-Al. Tensile (Ni-Ti) and compressive (Co-Ni-Al) tests were conducted to study the strain-induced transformation response in both of the alloy systems. It was found that the critical stress for transformation in both SMA systems was easily identified by a burst of AE activity during both transformation and reverse transformation. AE signals from these experiments were collected for use as training data for a Bayesian classifier to be used to identify transformation signals in a Al7050 matrix with embedded SMA particles. The Al/SMA composite was made by vacuum hot pressing SMA powder between aluminum plates. The effect of hot pressing temperature and subsequent heat treatments (solutionizing and peak aging) on the SMA particles was studied. It was found that, at the temperatures required, Co-Ni-Al developed a second phase that restricted the transformation from austenite to martensite, thus rendering it ineffective as a candidate for the embedded particles. Conversely, Ni-Ti did survive the embedding process and it was found that the solutionizing heat treatment applied after hot pressing was the main driver in determining the final transformation temperatures for the Ni-Ti particles. The effect of hot

  19. Hydrogen-environment-assisted cracking of an aluminum-zinc-magnesium(copper) alloy

    Science.gov (United States)

    Young, George Aloysius, Jr.

    There is strong evidence to indicate that hydrogen embrittlement plays a significant, if not controlling, role in the environmentally assisted cracking of 7XXX series aluminum alloys. In order to better understand hydrogen environment assisted cracking (HEAC), crack growth rate tests in the K-independent stage II crack growth regime were conducted on fracture mechanics specimens of an Al-6.09Zn-2.14Mg-2.19Cu alloy (AA 7050) and a low copper variant (Al-6.87Zn-2.65Mg-0.06Cu). Crack growth rate tests were performed in 90% relative humidity (RH) air between 25 and 90°C to assure hydrogen embrittlement control. The underaged, peak aged, and overaged tempers were investigated. Hydrogen uptake in humid air, hydrogen diffusion, and hydrogen trapping were investigated for each temper. Lastly, near crack tip hydrogen concentration depth profiles were analyzed via nuclear reaction analysis (NRA) and secondary ion mass spectroscopy (SIMS) using a liquid gallium, focused ion beam sputtering source (FIB/SIMS). The results of this study help explain and quantify empirically known trends concerning HEAC resistance and also establish new findings. In the copper bearing alloy, overaged tempers are more resistant but not immune to HEAC. Humid air is an aggressive environment for Al-Zn-Mg alloys because water vapor reacts with bare aluminum to produce high surface concentrations of hydrogen. This occurs in all tempers. Hydrogen diffuses from the near surface region to the high triaxial stress region ahead of the crack tip and collects at the high angle grain boundaries. The combination of tensile stress and high hydrogen concentration at the grain boundaries then causes intergranular fracture. Crack extension bares fresh metal and the process of hydrogen production, uptake, diffusion to the stressed grain boundary, and crack extension repeats. One reason increased degree of aging improves HEAC resistance in copper bearing 7XXX series alloys is that volume lattice and effective

  20. Optimization of process parameters of aluminum alloy AA 2014-T6 friction stir welds by response surface methodology

    OpenAIRE

    Ramanjaneyulu Kadaganchi; Madhusudhan Reddy Gankidi; Hina Gokhale

    2015-01-01

    The heat treatable aluminum–copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-to-weight ratio and good ductility. Friction stir welding (FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum allo...

  1. Hazard of ultraviolet radiation emitted in gas tungsten arc welding of aluminum alloys.

    Science.gov (United States)

    Nakashima, Hitoshi; Utsunomiya, Akihiro; Fujii, Nobuyuki; Okuno, Tsutomu

    2016-01-01

    Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema. The extent of the hazard of UVR varies depending on the welding method and conditions. Therefore, it is important to identify the levels of UVR that are present under various conditions. In this study, we experimentally evaluated the hazard of UVR emitted in gas tungsten arc welding (GTAW) of aluminum alloys. The degree of hazard of UVR is measured by the effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines. The effective irradiances measured in this study are in the range 0.10-0.91 mW/cm(2) at a distance of 500 mm from the welding arc. The maximum allowable exposure times corresponding to these levels are only 3.3-33 s/day. This demonstrates that unprotected exposure to UVR emitted by GTAW of aluminum alloys is quite hazardous in practice. In addition, we found the following properties of the hazard of UVR. (1) It is more hazardous at higher welding currents than at lower welding currents. (2) It is more hazardous when magnesium is included in the welding materials than when it is not. (3) The hazard depends on the direction of emission from the arc.

  2. The thickness of native oxides on aluminum alloys and single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Evertsson, J., E-mail: jonas.evertsson@sljus.lu.se [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Bertram, F. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Zhang, F. [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas Vg 51, 100 44 Stockholm (Sweden); Rullik, L.; Merte, L.R.; Shipilin, M. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Soldemo, M.; Ahmadi, S. [KTH Royal Institute of Technology, ICT, Material Physics, 16440 Kista (Sweden); Vinogradov, N.; Carlà, F. [ESRF, B.P. 220, 38043 Grenoble (France); Weissenrieder, J.; Göthelid, M. [KTH Royal Institute of Technology, ICT, Material Physics, 16440 Kista (Sweden); Pan, J. [KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas Vg 51, 100 44 Stockholm (Sweden); Mikkelsen, A. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden); Nilsson, J.-O. [Sapa Technology, Kanalgatan 1, 612 31 Finspång (Sweden); Lundgren, E. [Division of Synchrotron Radiation Research, Lund University, Box 118, 221 00 Lund (Sweden)

    2015-09-15

    Highlights: • We have determined the native oxide film thickness on several Al samples. • The results obtained from XRR and XPS show excellent agreement. • The results obtained from EIS show consistently thinner oxide films. • The oxides on the alloys are thicker than the oxides on the single crystals. - Abstract: We present results from measurements of the native oxide film thickness on four different industrial aluminum alloys and three different aluminum single crystals. The thicknesses were determined using X-ray reflectivity, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In addition, atomic force microscopy was used for micro-structural studies of the oxide surfaces. The reflectivity measurements were performed in ultra-high vacuum, vacuum, ambient, nitrogen and liquid water conditions. The results obtained using X-ray reflectivity and X-ray photoelectron spectroscopy demonstrate good agreement. However, the oxide thicknesses determined from the electrochemical impedance spectroscopy show a larger discrepancy from the above two methods. In the present contribution the reasons for this discrepancy are discussed. We also address the effect of the substrate type and the presence of water on the resultant oxide thickness.

  3. Temperature control for thermal treatment of aluminum alloy in a large-scale vertical quench furnace

    Institute of Scientific and Technical Information of China (English)

    沈玲; 贺建军; 喻寿益; 桂卫华

    2016-01-01

    The temperature control of the large-scale vertical quench furnace is very difficult due to its huge volume and complex thermal exchanges. To meet the technical requirement of the quenching process, a temperature control system which integrates temperature calibration and temperature uniformity control is developed for the thermal treatment of aluminum alloy workpieces in the large-scale vertical quench furnace. To obtain the aluminum alloy workpiece temperature, an air heat transfer model is newly established to describe the temperature gradient distribution so that the immeasurable workpiece temperature can be calibrated from the available thermocouple temperature. To satisfy the uniformity control of the furnace temperature, a second order partial differential equation (PDE) is derived to describe the thermal dynamics inside the vertical quench furnace. Based on the PDE, a decoupling matrix is constructed to solve the coupling issue and decouple the heating process into multiple independent heating subsystems. Then, using the expert control rule to find a compromise of temperature rising time and overshoot during the quenching process. The developed temperature control system has been successfully applied to a 31 m large-scale vertical quench furnace, and the industrial running results show the significant improvement of the temperature uniformity, lower overshoot and shortened processing time.

  4. Fatigue Properties and Fracture Mechanism of Aluminum Alloy with Orifice Chamfer and Pre-corrosion Damage

    Directory of Open Access Journals (Sweden)

    ZHOU Song

    2016-06-01

    Full Text Available Fatigue fracture often occurs because of the corrosion damage to aerospace structural aluminum alloy with holes. Fatigue tests of 7075 aluminum alloy of both unchamfered and chamfered double-hole specimens under uncorrosion and 24h pre-corrosion were carried out. The influence of both pre-corrosion damage and orifice chamferer on fatigue properties and the differences of fatigue fracture characteristics were analyzed. The results show that the effect on fatigue life of pre-corrosion damage is significant. Median fatigue lives of both unchamfered and chamfered double-hole specimens under 24h pre-corrosion decrease about 31.74% and 26.92% compared with uncorrosion specimens. The orifice chamferer have a certain effect on fatigue life of both uncorrosion and 24h pre-corrosion specimens, with median fatigue lives decreased about 28.02% and 15.36% compared with unchamfered specimens, the main reason is due to the stress concentration after orifice chamfered, on the other hand, cutting marks lead to pre-damage during the orifice chamfering process which will result in an increase of the fatigue crack initiation sites and the fracture probability.

  5. Joint performance of CO2 laser beam welding 5083-H321 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Qi Junfeng; Zhang Dongyun; Xiao Rongshi; Chen Kai; Zuo Tiechuan

    2007-01-01

    Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam autogenous welding and wire feed welding are conducted on 4mm thick 5083-H321 aluminum alloy sheets at different welding variables. The mechanical properties and microstructure characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Experimental results indicate that both the tensile strength and hardness of laser beam welds are affected by the constitution of filler material, except the yield strength. The soften region of laser beam welds is not in the heat-affected zone (HAZ). The tensile fracture of laser beam welded specimens takes place in the weld zone and close to the weld boundary because of different filler materials. Some pores are found on the fracture face, including hydrogen porosities and blow holes, but these pores have no influence on the tensile strength of laser beam welds. Tensile strength values of laser beam welds with filler wire are up to 345.57MPa, 93% of base material values, and yield strengths of laser beam welds are equivalent to those of base metal (264.50MPa).

  6. Effects of Electric Pulse Current on the Aging Kinetics of 2219 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Jiao Zhang

    2014-01-01

    Full Text Available The conventional aging experiments and the low density electric pulse current (LDEPC for short added aging experiments, with the self-made positive and negative alternating pulse power equipment, were conducted to study the influence of LDEPC on the dynamics of phase transformation in 2219 aluminum alloy by means of measuring the variation of hardness with aging time. The results showed that the hardness in both aging systems increased with the increasing of aging time until it reached the peak value; then it gradually reduced. The hardness of LDEPC added aging is generally greater than the conventional one before the peak aging time. The Avrami dynamics equation of conventional isothermal aging was obtained based on the hardness evolution law. The effects of electromigration and ponderomotive force were introduced into the Avrami empirical equation; in turn, the dynamics equation of LDEPC added aging was established. At last, the isothermal transformation curves of both the regular aging and the LDEPC added aging were derived which revealed that the nucleation rate, as well as the growth rate, was promoted by electric pulse current. The research work provided the theoretical support for the regulation of the coupling energy field on the dynamics of phase transformation in 2219 aluminum alloy.

  7. High level compressive residual stresses produced in aluminum alloys by laser shock processing

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Rosas, G. [Centro de Ingenieria y Desarrollo Industrial, CIDESI, Av. Playa Pie de la Cuesta, 702 Desarrollo San Pablo, c.p. 76130 Santiago de Queretaro, Queretaro (Mexico)]. E-mail: ggomez@cidesi.mx; Rubio-Gonzalez, C. [Centro de Ingenieria y Desarrollo Industrial, CIDESI, Av. Playa Pie de la Cuesta, 702 Desarrollo San Pablo, c.p. 76130 Santiago de Queretaro, Queretaro (Mexico); Ocana, J.L [Departamento de Fisica Aplicada a la Ingenieria Industrial, ETSII, Universidad Politecnica de Madrid (Spain); Molpeceres, C. [Departamento de Fisica Aplicada a la Ingenieria Industrial, ETSII, Universidad Politecnica de Madrid (Spain); Porro, J.A. [Departamento de Fisica Aplicada a la Ingenieria Industrial, ETSII, Universidad Politecnica de Madrid (Spain); Chi-Moreno, W. [Instituto Tecnologico de Morelia (Mexico); Morales, M. [Departamento de Fisica Aplicada a la Ingenieria Industrial, ETSII, Universidad Politecnica de Madrid (Spain)

    2005-11-15

    Laser shock processing (LSP) has been proposed as a competitive alternative technology to classical treatments for improving fatigue and wear resistance of metals. We present a configuration and results for metal surface treatments in underwater laser irradiation at 1064 nm. A convergent lens is used to deliver 1.2 J/cm{sup 2} in a 8 ns laser FWHM pulse produced by 10 Hz Q-switched Nd:YAG, two laser spot diameters were used: 0.8 and 1.5 mm. Results using pulse densities of 2500 pulses/cm{sup 2} in 6061-T6 aluminum samples and 5000 pulses/cm{sup 2} in 2024 aluminum samples are presented. High level of compressive residual stresses are produced -1600 MPa for 6061-T6 Al alloy, and -1400 MPa for 2024 Al alloy. It has been shown that surface residual stress level is higher than that achieved by conventional shot peening and with greater depths. This method can be applied to surface treatment of final metal products.

  8. Experimental Study of Stationary Shoulder Friction Stir Welded 7N01-T4 Aluminum Alloy

    Science.gov (United States)

    Ji, S. D.; Meng, X. C.; Li, Z. W.; Ma, L.; Gao, S. S.

    2016-03-01

    Stationary shoulder friction stir welding (SSFSW) was successfully used to weld 7N01-T4 aluminum alloy with the thickness of 4 mm. Effects of welding speed on formations, microstructures, and mechanical properties of SSFSW joint were investigated in detail. Under a constant rotational velocity of 2000 rpm, defect-free joints with smooth surface and small flashes are attained using welding speeds of 20 and 30 mm/min. Macrostructure of nugget zone in cross section presents kettle shape. For 7N01-T4 aluminum alloy with low thermal conductivity, decreasing welding speed is beneficial to surface formation of joint. With the increase of welding speed, mechanical properties of joints firstly increase and then decrease. When the welding speed is 30 mm/min, the tensile strength and elongation of joint reach the maximum values of 379 MPa and 7.9%, equivalent to 84.2 and 52% of base material, respectively. Fracture surface morphology exhibits typical ductile fracture. In addition, the minimum hardness value of joint appears in the heat affected zone.

  9. Evaluating the Applicability of GTN Damage Model in Forward Tube Spinning of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Xianxian Wang

    2016-06-01

    Full Text Available Tube spinning is an effective plastic-forming technology for forming light-weight, high-precision and high-reliability components in high-tech fields, such as aviation and aerospace. However, cracks commonly occur in tube spinning due to the complexity of stress state, which severely restricts the improvement of the forming quality and forming limit of components. In this study, a finite element (FE model coupled with Gurson-Tvergaard-Needleman (GTN damage model for forward tube spinning of 3A21-O aluminum alloy is established and its applicability is evaluated by experiment. Meanwhile, the GTN damage model is employed to study the damage evolution for forward tube spinning of 3A21-O aluminum alloy. The results show that the FE model is appropriate for predicting the macroscopic crack appearing in uplift area for forward tube spinning, while the damage evolution in deformation area could not be predicted well due to the negative stress triaxiality and the neglect of shear deformation. Accumulation of damage in forward tube spinning occurs mainly in the uplift area. Void volume fraction (VVF in the outer surface of the tube is higher than that in the inner surface. In addition, it is prone to cracking in the outer surface of tube in the material uplift area.

  10. Investigation of Material Performance Degradation for High-Strength Aluminum Alloy Using Acoustic Emission Method

    Directory of Open Access Journals (Sweden)

    Yibo Ai

    2015-02-01

    Full Text Available Structural materials damages are always in the form of micro-defects or cracks. Traditional or conventional methods such as micro and macro examination, tensile, bend, impact and hardness tests can be used to detect the micro damage or defects. However, these tests are destructive in nature and not in real-time, thus a non-destructive and real-time monitoring and characterization of the material damage is needed. This study is focused on the application of a non-destructive and real-time acoustic emission (AE method to study material performance degradation of a high-strength aluminum alloy of high-speed train gearbox shell. By applying data relative analysis and interpretation of AE signals, the characteristic parameters of materials performance were achieved and the failure criteria of the characteristic parameters for the material tensile damage process were established. The results show that the AE method and signal analysis can be used to accomplish the non-destructive and real-time detection of the material performance degradation process of the high-strength aluminum alloy. This technique can be extended to other engineering materials.

  11. Investigation on a Sol-gel Coating Containing Inhibitors on 2024-T3 Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    SHI Hong-wei; LIU Fu-chun; HAN En-hou; SUN Ming-cheng

    2006-01-01

    For a long time, chromate incorporated conversion coatings have been drawn special attention in corrosion protection of aircraft-used aluminum alloys. However,ever-increasing environmental pressures requires that non-chromate conversion coatings be developed because of the detrimental carcinogenic effects of the chromate compounds. In recent years, the sol-gel coatings doped with inhibitors were developed to replace chromate conversion coatings, and showed real promise. A sol-gel coating was prepared and its anti-corrosion behavior was investigated using the potentiodynamic scanning (PDS) and the electrochemical impedance spectroscopy (EIS). It is found that the sol-gel coating obtained by the hydrolysis and condensation of 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS) is prone to form defects if cured at the room temperature, whereas if cured at a higher temperature (100 ℃), these flaws can be avoided. Furthermore, it can be seen that addition of anti-foam agents and surfactants will reduce the faults if cured at the room temperature. Effects of the corrosion inhibitors, CeCl3 and mercaptobenzothiazole (MBT), in the sol-gel coatings on 2024-T3 aluminum alloy were also investigated. Results show that the corrosion resistance of the sol-gel coatings containing CeCl3 proves to be better than that of the pure and MBT added sol-gel coatings by the electrochemical methods.

  12. Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

    Science.gov (United States)

    Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

    2016-05-01

    Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

  13. Influence Of Lubricants On Wear Resistance Of Aluminum Alloy Strips Series 2XXX

    Directory of Open Access Journals (Sweden)

    Żaba K.

    2015-09-01

    Full Text Available The article presents a properly planned and designed tests of the abrasive wear resistance 2024 aluminum alloy strips under friction conditions involving various lubricants. Test were focused on the selection of the best lubricant for use in industrial environment, especially for sheet metal forming. Three lubricants of the Orlen Oil Company and one used in the sheet metal forming industry, were selected for tests. Tests without the use of lubricant were performed for a comparison. The tester T-05 was used for testing resistance to wear. As the counter samples were used tool steel - NC6 and steel for hot working - WCL, which are typical materials used for tools for pressing. The results are presented in the form of the force friction, abrasion depth, weight loss and coefficient of friction depending on the lubricant used and the type of counter samples. The results allowed for predicting set lubricant-material for tools which can be applied to sheet metal made of aluminum alloy 2024.

  14. Effect of temperature on the anodizing process of aluminum alloy AA 5052

    Science.gov (United States)

    Theohari, S.; Kontogeorgou, Ch.

    2013-11-01

    The effect of temperature (10-40 °C) during the anodizing process of AA 5052 for 40 min in 175 g/L sulfuric acid solution at constant voltage (15 V) was studied in comparison with pure aluminum. The incorporated magnesium species in the barrier layer result in the further increase of the minimum current density passed during anodizing, as the temperature increases, by about 42% up to 30 °C and then by 12% up to 40 °C. Then during the anodizing process for 40 min a blocking effect on oxide film growth was gradually observed as the temperature increased until 30 °C. The results of EDAX analysis on thick films reveal that the mean amount of the magnesium species inside the film is about 50-70% less than that in the bulk alloy, while it is higher at certain locations adjacent to the film surface at 30 °C. The increase of anodizing temperature does not influence the porosity of thin films (formed for short times) on pure aluminum, while it reduces it on the alloy. At 40 °C the above mentioned blocking effects disappear. It means that the presence of magnesium species causes an impediment to the effect of temperature on iss, on the film thickness and on the porosity of thin films, only under conditions where film growth takes place without significant loss of the anodizing charge to side reactions.

  15. Surface topographic characterization for polyamide composite injection molds made of aluminum and copper alloys.

    Science.gov (United States)

    Pereira, A; Hernández, P; Martinez, J; Pérez, J A; Mathia, T G

    2014-01-01

    In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW‐6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178‐604). The results are analyzed and differences between the two types of cavity inserts materials are discussed.

  16. Reaction behavior between the oxide film of LY12 aluminum alloy and the flux

    Institute of Scientific and Technical Information of China (English)

    薛松柏; 董健; 吕晓春; 顾文华

    2004-01-01

    In this paper, the brazing mechanism of LY12 aluminum alloy at middle range temperature was presented. The CsF-AlF3 non-corrosive flux was utilized to remove the complex oxide film on the surface of LY12 aluminum alloy. The results revealed that the oxide film was removed by the improved CsF-AlF3 flux accompanied with the occurrence of reaction as well as dissolution and the compounds CsF played an important role to remove the oxide film. Actually, the high activity of flux, say, the ability to remove the oxide film, was due to the presence of the compounds, such as NH4F,NH4AlF4 and composite molten salt. The production of HF was the key issue to accelerate the reaction and enhance to eliminate the oxide film by dissolution. It was found that the rare earth element La at small percentage was not enriched at the interface. Moreover, the rare earth fluoride enhanced the dissolution behavior.

  17. Multi-Track Friction Stir Lap Welding of 2024 Aluminum Alloy: Processing, Microstructure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Shengke Zou

    2016-12-01

    Full Text Available Friction stir lap welding (FSLW raises the possibility of fabricating high-performance aluminum components at low cost and high efficiency. In this study, we mainly applied FSLW to fabricate multi-track 2024 aluminum alloy without using tool tilt angle, which is important for obtaining defect-free joint but significantly increases equipment cost. Firstly, systematic single-track FSLW experiments were conducted to attain appropriate processing parameters, and we found that defect-free single-track could also be obtained by the application of two-pass processing at a rotation speed of 1000 rpm and a traverse speed of 300 mm/min. Then, multi-track FSLW experiments were conducted and full density multi-track samples were fabricated at an overlapping rate of 20%. Finally, the microstructure and mechanical properties of the full density multi-track samples were investigated. The results indicated that ultrafine equiaxed grains with the grain diameter about 9.4 μm could be obtained in FSLW samples due to the dynamic recrystallization during FSLW, which leads to a yield strength of 117.2 MPa (17.55% higher than the rolled 2024-O alloy substrate and an elongation rate of 31.05% (113.84% higher than the substrate.

  18. Preparation of semi-solid aluminum alloy slurry poured through a water-cooled serpentine channel

    Science.gov (United States)

    Chen, Zheng-Zhou; Mao, Wei-Min; Wu, Zong-Chuang

    2012-01-01

    A water-cooled serpentine channel pouring process was invented to produce semi-solid A356 aluminum alloy slurry for rheocasting, and the effects of pouring temperature and circulating cooling water flux on the microstructure of the slurry were investigated. The results show that at the pouring temperature of 640-680°C and the circulating cooling water flux of 0.9 m3/h, the semi-solid A356 aluminum alloy slurry with spherical primary α(Al) grains can be obtained, whose shape factors are between 0.78 and 0.86 and the grain diameter can reach 48-68 μm. When the pouring temperatures are at 660-680°C, only a very thin solidified shell remains inside the serpentine channel and can be removed easily. When the serpentine channel is cooled with circulating water, the microstructure of the semi-solid slurry can be improved, and the serpentine channel is quickly cooled to room temperature after the completion of one pouring. In terms of the productivity of the special equipment, the water-cooled serpentine channel is economical and efficient.

  19. Corrosion behavior on aluminum alloy LY12 in simulated atmospheric corrosion process

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-yao; MA Teng; HAN Wei; YU Guo-cai

    2007-01-01

    The corrosion behavior of typical high-strength aluminum alloy LY12 was studied by accelerated corrosion tests of cyclic wet-dry-immersion containing media of NaHSO3 and NaCl to simulate the corrosion process in different atmosphere environment, and the corrosion mechanism was also discussed. The main experimental techniques include mass loss, morphological check, analysis of corrosion products and electrochemical measurement. The result shows that the mass loss of LY12, with or without cladding, has linear relationship with test time in the three kinds of chemical media, 0.02 mol/L NaHSO3, 0.006 mol/L NaCl and 0.02 mol/L NaHSO3+0.006 mol/L NaCl, respectively. A layer of cladding on high-strength aluminum alloy can raise evidently the resistance of atmospheric corrosion. Cl- can promote pitting generation on the oxide film of LY12 when HOS3- exists, LY12 can react much intensely with HOS3- derived from anions.

  20. Microstructure and mechanical properties of GTAW welded joints of AA6105 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Minerva Dorta-Almenara

    2016-09-01

    Full Text Available Gas Tungsten Arc Welding (GTAW is one of the most used methods to weld aluminum. This work investigates the influence of welding parameters on the microstructure and mechanical properties of GTAW welded AA6105 aluminum alloy joints. AA6105 alloy plates with different percent values of cold work were joined by GTAW, using various combinations of welding current and speed. The fusion zone, in which the effects of cold work have disappeared, and the heat affected zone of the welded samples were examined under optical and scanning electron microscopes, additionally, mechanical tests and measures of Vickers microhardness were performed. Results showed dendritic morphology with solute micro- and macrosegregation in the fusion zone, which is favored by the constitutional supercooling when heat input increases. When heat input increased and welding speed increased or remained constant, greater segregation was obtained, whereas welding speed decrease produced a coarser microstructure. In the heat affected zone recrystallization, dissolution, and coarsening of precipitates occurred, which led to variations in hardness and strength.

  1. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Sabina Luisa Campanelli

    2013-12-01

    Full Text Available Friction Stir Welding (FSW is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  2. Acoustic Measurements of Residual Stresses and Grain Sizes in Aluminum Alloys

    Science.gov (United States)

    Fisher, Martin John

    The theory of acoustoelasticity relates the velocity of an acoustic wave in a solid to the elastic stress state in that solid. This thesis presents new theories, measurement techniques, and methodologies related to the use of longitudinal wave acoustoelasticity in aluminum alloys. A one-dimensional model has been developed to provide a simple understanding of the acoustoelastic effect. A new acoustic device for accurately measuring relative thickness variations has been designed and built. This device is used--in conjunction with a pulse-echo phase measurement device and a computer controlled scanning system--to measure acoustic velocity variations in plastically deformed and non-flat-and-parallel samples. Acoustic velocity variations from point to point in an unstressed sample can sometimes be on the same order as velocity changes due to applied or residual stresses, and this can make stress measurements difficult. A statistical theory has been developed to relate these unstressed velocity variations to the average grain size in the sample and to the active area of the acoustic transducer used. Large transducers and small grain sizes will minimize these variations. This relationship has been verified by tests on a number of aluminum alloys and a new method for non-destructive grain size determination has been suggested. A systematic methodology has been developed and tested for studying the influence of uniaxial plastic deformation on the acoustoelastic response. Samples have been plastically deformed in four-point bending to produce elastic-plastic and residual stress states. Acoustic measurements of these stresses have then been compared directly to theoretical predictions based on the materials' stress-strain curves and simple beam theory. In the aluminum alloys tested (2024-T351 and 7075-T651), the acoustoelastic constants are shown to be virtually unchanged by uniaxial plastic strains of less than 2.5%. Thus, the acoustoelastic technique can be reliably

  3. Membrane Lipid Peroxidation in Copper Alloy-Mediated Contact Killing of Escherichia coli

    OpenAIRE

    Hong,Robert; Kang, Tae Y.; Michels, Corinne A.; Gadura, Nidhi

    2012-01-01

    Copper alloy surfaces are passive antimicrobial sanitizing agents that kill bacteria, fungi, and some viruses. Studies of the mechanism of contact killing in Escherichia coli implicate the membrane as the target, yet the specific component and underlying biochemistry remain unknown. This study explores the hypothesis that nonenzymatic peroxidation of membrane phospholipids is responsible for copper alloy-mediated surface killing. Lipid peroxidation was monitored with the thiobarbituric acid-r...

  4. Effects of aluminum additions to gas atomized reaction synthesis produced oxide dispersion strengthened alloys

    Science.gov (United States)

    Spicher, Alexander Lee

    The production of an aluminum containing ferritic oxide dispersion strengthened (ODS) alloy was investigated. The production method used in this study was gas atomization reaction synthesis (GARS). GARS was chosen over the previously commercial method of mechanical alloying (MA) process due to complications from this process. The alloy compositions was determined from three main components; corrosion resistance, dispersoid formation, and additional elements. A combination of Cr and Al were necessary in order to create a protective oxide in the steam atmosphere that the boiler tubing in the next generation of coal-fired power plants would be exposed to. Hf and Y were chosen as dispersoid forming elements due to their increased thermal stability and potential to avoid decreased strength caused by additions of Al to traditional ODS materials. W was used as an additive due to benefits as a strengthener as well as its benefits for creep rupture time. The final composition chosen for the alloy was Fe-16Cr-12Al-0.9W-0.25Hf-0.2Y at%. The aforementioned alloy, GA-1-198, was created through gas atomization with atomization gas of Ar-300ppm O2. The actual composition created was found to be Fe-15Cr-12.3Al-0.9W-0.24Hf-0.19Y at%. An additional alloy that was nominally the same without the inclusion of aluminum was created as a comparison for the effects on mechanical and corrosion properties. The actual composition of the comparison alloy, GA-1-204, was Fe-16Cr-0Al-0.9W-0.25Hf-0.24Y at%. An investigation on the processing parameters for these alloys was conducted on the GA-1-198 alloy. In order to predict the necessary amount of time for heat treatment, a diffusion study was used to find the diffusion rate of oxygen in cast alloys with similar composition. The diffusion rate was found to be similar to that of other GARS compositions that have been created without the inclusion of aluminum. The effect of heat treatment time was investigated with temperatures of 950°C, 1000

  5. RESEARCH ON THE WARM FORGING OF ALUMINUM ALLOYS:DEVELOPMENT OF A FORMULA TO DESCRIBE THE SOFTENING BEHAVIOR OF A2011 IN FORGING PROCESS

    Institute of Scientific and Technical Information of China (English)

    X.H. Zhang, K. Osakada; X. Y. Ruan

    2003-01-01

    To understand the forming behaviour of aluminum alloys, the upsetting test of alu-minum alloys at evaluated temperature is conducted. Because in warm forging theflow stress decreases with increasing straining, which is so-called work softening, noappropriate material formulation is available. For the evaluation of flow stress ofaluminum alloys in warm forging processes, in this paper, a formula is derived byanalyzing the stress data measured at various temperatures. It is demonstrated thatthe formula fits the flow stress obtained from experiment.

  6. Surface Characterization of Carbon Fiber Polymer Composites and Aluminum Alloys After Laser Interference Structuring

    Science.gov (United States)

    Sabau, Adrian S.; Greer, Clayton M.; Chen, Jian; Warren, Charles D.; Daniel, Claus

    2016-07-01

    The increasing use of carbon fiber-reinforced polymer matrix composites (CFPC) and aluminum alloys as lightweight materials in the automotive and aerospace industries demands enhanced surface preparation and control of surface morphology prior to joining. In this study, surfaces of both composite and aluminum were prepared for joining using an Nd:YAG laser in a two-beam interference setup, enabling the (1) structuring of the AL 5182 surface, (2) removal of the resin layer on top of carbon fibers, and (3) structuring of the carbon fibers. CFPC specimens of T700S carbon fiber, Prepreg—T83 epoxy, 5 ply thick, 0°/90° plaques were used. The effects of laser fluence, scanning speed, and number of shots-per-spot were investigated on the removal rate of the resin without an excessive damage of the fibers. Optical micrographs, 3D imaging, and scanning electron microscope imaging were used to study the effect of the laser processing on the surface morphology. It was found that an effective resin ablation and a low density of broken fibers for CFPC specimens was attained using laser fluences of 1-2 J/cm2 and number of 2-4 pulses per spot. A relatively large area of periodic line structures due to energy interference were formed on the aluminum surface at laser fluences of 12 J/cm2 and number of 4-6 pulses per spot.

  7. Microstructural and hardness behavior of graphene-nanoplatelets/aluminum composites synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Bustamante, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Bolaños-Morales, D.; Bonilla-Martínez, J. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ingeniería, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Estrada-Guel, I. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico)

    2014-12-05

    Highlights: • Pure aluminum was reinforced with graphene-platelets by using mechanical milling. • The composites were studied after sintering condition. • Milling time and graphene-platelet enhance the mechanical behavior of the composites. - Abstract: Graphene can be considered as an ideal reinforcement for the production of composites due to its outstanding mechanical properties. These characteristics offer an increased opportunity for their study in the production of metal matrix composites (MMCs). In this research, the studied composites were produced by mechanical alloying (MA). The employed milling times were of 1, 3 and 5 h. GNPs were added in 0.25, 0.50 and 1.0 wt% into an aluminum powder matrix. Milled powders were cold consolidated and subsequently sintered. Composites were microstructurally characterized with Raman spectroscopy and electron microscopy and X-ray diffraction. The hardness behavior in composites was evaluated with a Vickers micro-hardness test. A homogeneous dispersion of graphene during MA and the proper selection of sintering conditions were considered to produce optimized composites. The obtained results with electron microscopy indicate a homogeneous dispersion of GNPs into the aluminum matrix. Analyses showed GNPs edges where the structure of the graphene layers conserved after MA is observed.

  8. Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars

    Directory of Open Access Journals (Sweden)

    de Rincón, O.

    2003-12-01

    Full Text Available This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermosprayed aluminum (3-year evaluation and conventional Al/Zn/In anocies in an epoxy-painted steel bracelet (12-year evaluation, indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermosprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials ( < -1100 mV vs. Cu/CuSO4 they supply to the reinforcement could lead to hydrogen embrittlement.

    Este trabajo presenta la realización de varios diseños de protección catódica utilizando aleaciones de aluminio para la protección de pilotes pretensados. Los resultados obtenidos con diferentes diseños (aleación de Al/Zn/In, tipo brazalete y aluminio termorociado (3 años de evaluación y ánodos convencionales de Al/Zn/In colocados en un brazalete de acero pintado con epoxy (12 años de evaluación, indicaron que todos estos sistemas pueden ser utilizados como ánodos de sacrificio para la protección de los pilotes. Sin embargo, el sistema con aluminio termorociado no puede ser utilizado en pilotes de acero pretensado debido al potencial muy negativo alcanzado por la armadura (<-1100 mV vs Cu/CuSO4, lo cual podría inducir a daños por hidrógeno.

  9. Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

    Science.gov (United States)

    Ma, Zheyuan

    Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM

  10. Stress Corrosion Cracking in Al-Zn-Mg-Cu Aluminum Alloys in Saline Environments

    Science.gov (United States)

    Holroyd, N. J. Henry; Scamans, G. M.

    2013-03-01

    Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack ("pop-in" vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies ( E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (alloys (>~0.8 wt pct), they are typically

  11. Effect of chemical composition variation on microstructure and mechanical properties of a 6060 aluminum alloy

    Science.gov (United States)

    Silva, M. S.; Barbosa, C.; Acselrad, O.; Pereira, L. C.

    2004-04-01

    The 6XXX series aluminum alloys (Al-Mg-Si) are widely used in many different engineering and architectural applications. These alloys usually undergo a thermal treatment, which consists of a heat treatment solution and artificial aging, since the desirable mechanical properties depend on the microstructural state of the material. The recycling of materials has been increasing recently for economic and ecologic reasons. By using scrap was raw material, important reductions in energy and total costs can be achieved, and, at the same time, negative environmental impacts can be greatly reduced. In the present work, the possibility of using a larger amount of scrap as raw material in the production of an AA 6060 alloy is evaluated by analyzing the difference in microstructure and mechanical properties between a commercial 6060 alloy and a variation with higher Fe and lower Si contents that was specially produced for this study. Both materials were placed into a heat treatment solution at 560 °C for 1 h, and then underwent water quenching followed by artificial aging at 180 °C for different periods of time. Hardness and tension tests were used to evaluate the mechanical properties. Light and transmission electron microscopy have been used to determine important features such as grain size before and after being placed into the heat treatment solution, and the characteristics of the second-phase particles in the two materials. This study leads to the conclusion that a higher amount of scrap material can be used in the production of 6060 Al alloy without significant changes in mechanical properties compared with the more usual compositions.

  12. Dynamic and Thermal Properties of Aluminum Alloy A356/Silicon Carbide Hollow Particle Syntactic Foams

    Directory of Open Access Journals (Sweden)

    James Cox

    2014-12-01

    Full Text Available Aluminum alloy A356 matrix syntactic foams filled with SiC hollow particles (SiCHP are studied in the present work. Two compositions of syntactic foams are studied for quasi-static and high strain rate compression. In addition, dynamic mechanical analysis is conducted to study the temperature dependent energy dissipation and damping capabilities of these materials. The thermal characterization includes study of the coefficient of thermal expansion (CTE. A356/SiCHP syntactic foams are not strain rate sensitive as the compressive strength displayed little variation between the tested strain rates of 0.001–2100 s−1. Microscopic analysis of the high strain rate compression tested specimens showed that the fracture is initiated by the failure of hollow particles at the onset of the plastic deformation region. This is followed by plastic deformation of the matrix material and further crushing of particles. The syntactic foams showed decrease in storage modulus with increasing temperature and the trend was nearly linear up to 500 °C. The alloy shows a similar behavior at low temperature but the decrease in storage modulus increases sharply over 375 °C. The loss modulus is very small for the tested materials because of lack of viscoelasticity in metallic materials. The trend in the loss modulus is opposite, where the matrix alloy has lower loss modulus than syntactic foams at low temperature. However, over 250 °C the matrix loss modulus starts to increase rapidly and attains a peak around 460 °C. Syntactic foams have higher damping parameter at low temperatures than the matrix alloy. Incorporation of SiCHP helps in decreasing CTE. Compared to the CTE of the matrix alloy, 23.4 × 10−6 °C−1, syntactic foams showed CTE values as low as 11.67 × 10−6 °C−1.

  13. Chemical removal of nitrate from water by aluminum-iron alloys.

    Science.gov (United States)

    Xu, Jie; Pu, Yuan; Qi, Wei-Kang; Yang, Xiao Jin; Tang, Yang; Wan, Pingyu; Fisher, Adrian

    2017-01-01

    Zero-valent iron has been intensively investigated in chemical reduction of nitrate in water, but the reduction requires acidic or weak acidic pH conditions and the product of the reduction is exclusively ammonium, an even more toxic substance. Zero-valent aluminum is a stronger reductant than iron, but its use for the reduction of aqueous nitrate requires considerably alkaline pH conditions. In this study, aluminum-iron alloys with an iron content of 10%, 20% and 58% (termed Al-Fe10, Al-Fe20 and Al-Fe58, respectively) were investigated for the reduction of aqueous nitrate. Al-Fe alloys were efficient to reduce nitrate in water in an entire pH range of 2-12 and the reduction proceeded in a pseudo-first order at near neutral pH conditions. The observed reaction rate constant (Kobs) of Al-Fe10 was 3 times higher than that of Fe and the Kobs of Al-Fe20 doubled that of Al-Fe10. The nitrogen selectivity of the reduction by Al-Fe10, Al-Fe20 and Al-Fe58 was 17.6%, 23.9% and 40.3%, respectively at pH 7 and the nitrogen selectivity by Al-Fe20 increased from 18.9% at pH 2-60.3% at pH 12. The enhanced selectivity and reactivity of Al-Fe alloys were likely due to the presence of an intermetallic Al-Fe compound (Al13Fe4).

  14. Structure-property relationships of dissimilar friction stir welded aluminum alloys

    Science.gov (United States)

    Quinones, Rogie Irwin Rodriguez

    In this work, the relationship between microstructure and mechanical properties of dissimilar friction stir welded AA6061-to-AA7050 aluminum alloys were evaluated. Experimental results from this study revealed that static strength increased with the tool rotational speed and was correlated with the material intermixing. Fully-reversed low cycle fatigue experimental results showed an increase in the strain hardening properties as well as the number of cycles-to-failure as the tool rotational speed was increased. Furthermore, under both static and cyclic loading, fracture of the joint was dominated by the AA6061 alloy side of the weld. In addition, inspection of the fatigue surfaces revealed that cracks initiated from intermetallic particles located near the surface. In order to determine the corrosion resistance of the dissimilar joint, corrosion defects were produced on the crown surface of the weld by static immersion in 3.5% NaCl for various exposure times. Results revealed localized corrosion damage in the thermo-mechanically affected and heat affected zones. Results demonstrated a decrease in the fatigue life, with evidence of crack initiation at the corrosion defects; however, the fatigue life was nearly independent of the exposure time. This can be attributed to total fatigue life dominated by incubation time. Furthermore, two types of failure were observed: fatigue crack initiation in the AA6061 side at high strain amplitudes (>0.3%); and fatigue crack initiation in the AA7050 side at low strain amplitudes (friction stir welded joints in order to capture the crack initiation and propagation in as-welded and pre-corroded conditions. Good correlation between experimental fatigue results and the model was achieved based on the variation in the initial defect size, microstructure, and mechanical properties of the dissimilar friction stir welded AA6061-to-AA7050 aluminum alloys.

  15. Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

    Science.gov (United States)

    Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

    1973-01-01

    Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

  16. Aluminum alloy weldability. Identification of weld solidification cracking mechanisms through novel experimental technique and model development

    Energy Technology Data Exchange (ETDEWEB)

    Coniglio, Nicolas

    2008-07-01

    The objective of the present thesis is to make advancements in understanding solidification crack formation in aluminum welds, by investigating in particular the aluminum 6060/4043 system. Alloy 6060 is typical of a family of Al-Mg-Si extrusion alloys, which are considered weldable only when using an appropriate filler alloy such as 4043 (Al-5Si). The effect of 4043 filler dilution (i.e. weld metal silicon content) on cracking sensitivity and solidification path of Alloy 6060 welds are investigated. Afterwards, cracking models are developed to propose mechanisms for solidification crack initiation and growth. Cracking Sensitivity. Building upon the concept that silicon improves weldability and that weldability can be defined by a critical strain rate, strain rate-composition combinations required for solidification crack formation in the Al- 6060/4043 system were determined using the newly developed Controlled Tensile Weldability (CTW) test utilizing local strain extensometer measurements. Results, presented in a critical strain rate - dilution map, show a crack - no crack boundary which reveals that higher local strain rates require higher 4043 filler dilution to avoid solidification cracking when arc welding Alloy 6060. Using the established crack - no crack boundary as a line of reference, additional parameters were examined and their influence on cracking characterized. These parameter influences have included studies of weld travel speed, weld pool contaminants (Fe, O, and H), and grain refiner additions (TiAl{sub 3} + Boron). Each parameter has been independently varied and its effect on cracking susceptibility quantified in terms of strain rate - composition combinations. Solidification Path. Solidification path of the Al-6060/4043 system was characterized using thermal analysis and phase identification. Increasing 4043 filler dilution from 0 to 16% in Alloy 6060 arc welds resulted in little effect on thermal arrests and microstructure, no effect on

  17. Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla

    2005-10-31

    Conventional processing methods for highly alloyed aluminum consist of ingot casting, followed by hot rolling and thermal treatments. Defects result in lost productivity and wasted energy through the need to remelt and reprocess the material. This research centers on developing a fundamental understanding for deformation of wrought 705X series alloys, a key alloy system used in structural airframe applications. The development of damage at grain boundaries is characterized through a novel test that provides initiation of failure while preserving a controlled deformation response. Data from these mechanical tests are linked to computer simulations of the hot rolling process through a critical measure of damage. Transmission electron microscopy provides fundamental insight into deformation at these high working temperatures, and--in a novel link between microscale and macroscale response--the evolution of microstructure (crystallographic orientation) provides feedback for tuning of friction in the hot rolling process. The key product of this research is a modeling framework for the analysis of industrial hot rolling.

  18. Characterization of Phases in an As-cast Copper-Manganese-Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    J.Iqbal, F.Hasan; F.Ahmad

    2006-01-01

    Copper-manganese-aluminum (CMA) alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast (CMA) alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientationrelationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.

  19. Test and Analysis of Sub-Components of Aluminum-Lithium Alloy Cylinders

    Science.gov (United States)

    Haynie, Waddy T.; Chunchu, Prasad B.; Satyanarayana, Arunkumar; Hilburger, Mark W.; Smith, Russell W.

    2012-01-01

    Integrally machined blade-stiffened panels subjected to an axial compressive load were tested and analyzed to observe the buckling, crippling, and postcrippling response of the panels. The panels were fabricated from aluminum-lithium alloys 2195 and 2050, and both alloys have reduced material properties in the short transverse material direction. The tests were designed to capture a failure mode characterized by the stiffener separating from the panel in the postbuckling range. This failure mode is attributed to the reduced properties in the short transverse direction. Full-field measurements of displacements and strains using three-dimensional digital image correlation systems and local measurements using strain gages were used to capture the deformation of the panel leading up to the failure of the panel for specimens fabricated from 2195. High-speed cameras were used to capture the initiation of the failure. Finite element models were developed using an isotropic strain-hardening material model. Good agreement was observed between the measured and predicted responses for both alloys.

  20. Microstructure and Mechanical Properties of Friction Stir Welded 5083 and 7075 Aluminum Alloys

    Science.gov (United States)

    Kalemba-Rec, I.; Hamilton, C.; Kopyściański, M.; Miara, D.; Krasnowski, K.

    2017-02-01

    Through microscopy, mechanical testing, and numerical modeling, the microstructure and mechanical performance of friction stir welded aluminum alloys 7075-T651 and 5083-H111 were characterized. In particular, the influence of the weld configuration, i.e., the locations of the 7075 and 5083 alloys alternately on the advancing and retreating sides, on material flow, microstructure, and mechanical properties was considered. Thermographic data in conjunction with a process simulation demonstrated that the weld configuration significantly impacts heat generation during friction stir welding. The microstructure in the stir zone was a clear visualization of the material flow and was characterized by a vortex-like structure with alternating bands of the alloys being joined. These bands differed in elemental content and grain size. The microstructure became more complex when greater heat generation (higher temperatures) occurred. The weld configuration strongly influenced the material flow, but did not impact the tensile properties (such as yield strength, tensile strength, and elongation). The configuration of 5083 on the advancing side and 7075 on the retreating side produced the most uniform material flow. The joint efficiencies of all tested welds were above 100%.

  1. Grain size effect on yield strength of titanium alloy implanted with aluminum ions

    Energy Technology Data Exchange (ETDEWEB)

    Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Yurev, Ivan, E-mail: yiywork@mail.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: kmp1980@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Kurzina, Irina, E-mail: kurzina99@mail.ru [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation)

    2016-01-15

    The paper presents a transmission electron microscopy (TEM) study of the microstructure and phase state of commercially pure titanium VT1-0 implanted by aluminum ions. This study has been carried out before and after the ion implantation for different grain size, i.e. 0.3 µm (ultra-fine grain condition), 1.5 µm (fine grain condition), and 17 µm (polycrystalline condition). This paper presents details of calculations and analysis of strength components of the yield stress. It is shown that the ion implantation results in a considerable hardening of the entire thickness of the implanted layer in the both grain types. The grain size has, however, a different effect on the yield stress. So, both before and after the ion implantation, the increase of the grain size leads to the decrease of the alloy hardening. Thus, hardening in ultra-fine and fine grain alloys increased by four times, while in polycrystalline alloy it increased by over six times.

  2. Near-Surface Microstructure on Twin-Roll Cast 8906 Aluminum Alloy

    Science.gov (United States)

    Wang, Junjie; Zhou, Xiaorong; Thompson, George E.; Hunter, John A.; Yuan, Yudie

    2015-06-01

    The microstructure of the near-surface region of twin-roll cast foil stock 8906 AlFeSi alloy has been investigated. It was revealed that a near-surface layer with microstructure differing from that of the underlying bulk alloy was generated due to severe surface shear strain during twin-roll casting. Scanning and transmission electron microscopy showed that the near-surface layer consists of nano-sized grains with diameters varying in the range of 50 to 600 nm. Energy dispersive X-ray spectroscopy revealed that grain boundaries within the near-surface layer were decorated by aluminum oxide particles and carbon-containing lubricant inclusions. Preferential precipitation of a high population density of cubic α-AlFeSi dispersoids, of 30 to 150 nm diameter, was observed within the near-surface layer. The near-surface layer was associated with shingles on the twin-roll cast alloy surface and the maximum layer thickness of approximately 6 µm was observed at the shingles. Other areas of the surface were either free of the near-surface layer or had a thinner near-surface layer.

  3. Protective film formation on AA2024-T3 aluminum alloy by leaching of lithium carbonate from an organic coating

    NARCIS (Netherlands)

    Liu, Y.; Visser, P.; Zhou, X.; Lyon, S.B.; Hashimoto, T.; Curioni, M.; Gholinia, A.; Thompson, G.E.; Smyth, G.; Gibbon, S.R.; Graham, D.; Mol, J.M.C.; Terryn, H.A.

    2015-01-01

    An investigation into corrosion inhibition properties of a primer coating containing lithium carbonate as corrosion inhibitive pigment for AA2024 aluminum alloy was conducted. It was found that, during neutral salt spray exposure, a protective film of about 0.2 to 1.5 μm thickness formed within the

  4. A study of aluminum-lithium alloy solidification using acoustic emission techniques. Ph.D. Thesis, 1991

    Science.gov (United States)

    Henkel, Daniel P.

    1992-01-01

    Physical phenomena associated with the solidification of an aluminum lithium alloy was characterized using acoustic emission (AE) techniques. It is shown that repeatable patterns of AE activity may be correlated to microstructural changes that occur during solidification. The influence of the experimental system on generated signals was examined in the time and frequency domains. The analysis was used to show how an AE signal from solidifying aluminum is changed by each component in the detection system to produce a complex waveform. Conventional AE analysis has shown that a period of high AE activity occurs in pure aluminum, an Al-Cu alloy, and the Al-Li alloy, as the last fraction of solid forms. A model attributes this to the internal stresses of grain boundary formation. An additional period of activity occurs as the last fraction of solid forms, but only in the two alloys. A model attributes this to the formation of interdendritic porosity which was not present in the pure aluminum. The AE waveforms were dominated by resonant effects of the waveguide and the transducer.

  5. Process design for Al backside contacts

    Energy Technology Data Exchange (ETDEWEB)

    Chalfoun, L.L.; Kimerling, L.C. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1995-08-01

    It is known that properly alloyed aluminum backside contacts can improve silicon solar cell efficiency. To use this knowledge to fullest advantage, we have studied the gettering process that occurs during contact formation and the microstructure of the contact and backside junction region. With an understanding of the alloying step, optimized fabrication processes can be designed. To study gettering, single crystal silicon wafers were coated with aluminim on both sides and subjected to heat treatments. Results are described.

  6. Influence of the Peak Tensile Overload Cycles on the Fatigue Crack Growth of Aluminum Alloy Under Spectrum Loading

    Science.gov (United States)

    Iranpour, Mohammad; Taheri, Farid

    2013-11-01

    Many structures such as aircrafts, risers, and offshore pipelines that are in contact with fluids, become subjected to complex variable amplitude loading (VAL) stress-time histories during their service lives. As a result, the structural life assessment and damage-tolerant analyses of such structures are considered as two important design criteria. In this paper, a VAL stress-time history is used to study the fatigue life of 6061-T651 aluminum alloy, with focus on the retardation effect resulting from the applied peak tensile overload cycles (TOLCs). Various so-called "clipping" levels are tested, and the results are compared with those obtained through an analytical method, using the Willenborg retardation approach, in conjunction with the Walker fatigue crack growth model. The results would demonstrate the significant influence of the TOLC present within VAL scenarios on retarding the fatigue crack growth rate of the material. The study also investigates the influence of various clipping levels on the fatigue response of the material, also highlighting the limitations of the analytical approach in estimating the resulting crack growth rate. It is observed that the analytical method predicts a higher fatigue life for the material subjected to VAL, which is non-conservative for design purposes. Some suggestions are provided for fatigue life estimation of the material when subjected to VAL scenarios.

  7. Microstructures and properties analysis of dissimilar metal joint in the friction stir welded copper to aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Wang Xijing; Zhang Zhongke; Da Chaobing; Li Jing

    2007-01-01

    This paper mainly concentrated on the feasibility of friction stir welding of dissimilar metal of aluminum alloy to copper (T2) and a preliminary analysis of welding parameters influencing on the microstructures and properties of joint was carried out. The results indicated that the thickness of workpiece played an important role in the welding parameters which could succeed in the friction stir welding of dissimilar metal of copper to aluminum alloy, and the parameters were proved to be a narrow choice. The interfacial region between copper and aluminum in the dissimilar joint was not uniformly mixed, constituted with part of incomplete mixing zone, complete mixing zone, dispersion zone and the most region's boundary was obvious. Meantime a kind banded structure with inhomogeneous width was formed. The intermetallic compounds generated during friction stir welding in the interfacial region were mainly Cu9Al4 , Al2Cu etc, and their hardness was higher than others.

  8. Numerical Simulation and Experimental Characterization of a Binary Aluminum Alloy Spray - Application to the Spray Rolling Process

    Energy Technology Data Exchange (ETDEWEB)

    S. B. Johnson; J.-P. Delplanque; Y. Lin; Y. Zhou; E. J. Lavernia; K. M. McHugh

    2005-02-01

    A stochastic, droplet-resolved model has been developed to describe the behavior of a binary aluminum alloy spray during the spray-rolling process. In this process, a molten aluminum alloy is atomized and the resulting spray is depostied on the rolls of a twin-roll caster to produce aluminum strip. The one-way coupled spray model allows the prediction of spray characteristics such as enthalph and solid fraction, and their distribution between the nozzle and the depostion surface. This paper outlines the model development and compares the predicted spray dynamics to PDI measurements performed in a controlled configuration. Predicted and measured droplet velocity and size distributions are presented for two points along the spray centerline along with predicted spray averaged specific enthalph and solid fraction curves.

  9. Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys and its mechanism

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys, which contain a small amount of intermetallic compounds Al3Ti or Al3Zr, was investigated. With this new method, the heat resistant properties of the bonding zone metal are improved, and the joints' strengths at high temperature is increased. The joints' shear strength at room temperature and at 600  ℃ reach 126~133  MPa and 32~34  MPa, respectively, with suitable bonding pressure. The reaction between aluminum and Si3N4 ceramics, which produces Al-Si-N-O type compounds is the dominant interfacial reaction, while the reactions between the second active element Ti or Zr in the aluminum based alloys and Si3N4 ceramics also occur to some extend.

  10. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    Science.gov (United States)

    Lee, Jonathan A.

    2009-01-01

    In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

  11. An electrochemical investigation of the corrosion behavior of aluminum alloys in chloride containing solutions; Investigacao eletroquimica da corrosao de ligas de aluminio em solucoes contendo cloretos

    Energy Technology Data Exchange (ETDEWEB)

    Campos Filho, Jorge Eustaquio de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Engenharia. Dept. de Engenharia Quimica]. E-mail: jorgecamposfilho@yahoo.com.br; Neves, Celia de Figueiredo Cordeiro; Campos, Wagner Reis da Costa; Moreira, Marcilio Soares [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: caf@cdtn.br; wrcc@cdtn.br; msm@cdtn.br

    2005-07-01

    Aluminum alloys have been used as cladding materials for nuclear fuel in research reactors due to its corrosion resistance. Aluminum owes its good corrosion resistance to a protective barrier oxide film formed and strongly bonded to its surface. In pool type TRIGA IPR-R1 reactor, located at Centro de Desenvolvimento da Tecnologia Nuclear in Belo Horizonte, previous immersion coupon tests revealed that aluminum alloys suffer from pitting corrosion, in spite of high quality of water control. Corrosion attack is initiated by breaking the protective oxide film on aluminum alloy surface. Chloride ions can break this oxide film and stimulate metal dissolution. In this study the aluminum alloys 1050, 5052 and 6061 were used to evaluate their corrosion behavior in chloride containing solutions. The electrochemical techniques used were potentiodynamic anodic polarization and cyclic polarization. Results showed that aluminum alloys 5052 and 6061 present similar corrosion resistance in low chloride solutions (0,1 ppm NaCl) and in reactor water but both alloys are less resistant in high chloride solution (1 ppm NaCl). Aluminum alloy 1050 presented similar behavior in the three electrolytes used, regarding to pitting corrosion, indicating that the concentration of the chloride ions was not the only variable to influence its corrosion susceptibility. (author)

  12. Identifying Combination of Friction Stir Welding Parameters to Maximize Strength of Lap Joints of AA2014-T6 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Rajendrana C.

    2017-01-01

    Full Text Available AA2014 aluminum alloy (Al-Cu alloy has been widely utilized in fabrication of lightweight structures like aircraft structures, demanding high strength to weight ratio and good corrosion resistance. The fusion welding of these alloys will lead to solidification problems such as hot cracking. Friction stir welding is a new solid state welding process, in which the material being welded does not melt and recast. Lot of research works have been carried out by many researchers to optimize process parameters and establish empirical relationships to predict tensile strength of friction stir welded butt joints of aluminum alloys. However, very few investigations have been carried out on friction stir welded lap joints of aluminum alloys. Hence, in this investigation, an attempt has been made to optimize friction stir lap welding (FSLW parameters to attain maximum tensile strength using statistical tools such as design of experiment (DoE, analysis of variance (ANOVA, response graph and contour plots. By this method, it is found that maximum tensile shear fracture load of 12.76 kN can be achieved if a joint is made using tool rotational speed of 900 rpm, welding speed of 110 mm/min, tool shoulder diameter of 12 mm and tool tilt angle of 1.5°.

  13. Evaluation of precipitates used in strainer head loss testing: Part II. Precipitates by in situ aluminum alloy corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Bahn, Chi Bum, E-mail: bahn@anl.go [Argonne National Laboratory, Lemont, IL 60439 (United States); Kasza, Ken E.; Shack, William J.; Natesan, Ken [Argonne National Laboratory, Lemont, IL 60439 (United States); Klein, Paul [The United States Nuclear Regulatory Commission, Rockville, MD 20852 (United States)

    2011-05-15

    Graphical abstract: Display Omitted Research highlights: Sump strainer head loss testing to evaluate chemical effects. Aluminum hydroxide precipitates by in situ Al alloy corrosion caused head loss. Intermetallic particles released from Al alloy can also cause significant head loss. When evaluating Al effect on head loss, intermetallics should be considered. - Abstract: Vertical loop head loss tests were performed with 6061 and 1100 aluminum (Al) alloy plates immersed in borated solution at pH = 9.3 at room temperature and 60 {sup o}C. The results suggest that the potential for corrosion of an Al alloy to result in increased head loss across a glass fiber bed may depend on its microstructure, i.e., the size distribution and number density of intermetallic particles that are present in Al matrix and FeSiAl ternary compounds, as well as its Al release rate. Per unit mass of Al removed from solution, the WCAP-16530 aluminum hydroxide (Al(OH){sub 3}) surrogate was more effective in increasing head loss than the Al(OH){sub 3} precipitates formed in situ by corrosion of Al alloy. However, in choosing a representative amount of surrogate for plant specific testing, consideration should be given to the potential for additional head losses due to intermetallic particles and the apparent reduction in the effective solubility of Al(OH){sub 3} when intermetallic particles are present.

  14. The effect of hot isostatic pressing on crack initiation, fatigue, and mechanical properties of two cast aluminum alloys

    Science.gov (United States)

    Rich, T. P.; Orbison, J. G.; Duncan, R. S.; Olivero, P. G.; Peterec, R. H.

    1999-06-01

    This article presents the results of an experimental materials testing program on the effect of hot isostatic pressing (HIP) on the crack initiation, fatigue, and mechanical properties of two cast aluminum alloys: AMS 4220 and 4225. These alloys are often used in castings for high temperature applications. Standard tensile and instrumented Charpy impact tests were performed at room and elevated temperatures. The resulting data quantify improvements in ultimate tensile strength, ductility, and Charpy impact toughness from the HIP process while indicating little change in yield strength for both alloys. In addition standard fracture mechanics fatigue tests along with a set of unique fatigue crack initiation tests were performed on the alloys. Hot isostatic pressing was shown to produce a significant increase in cycles to crack initiation for AMS 4225, while no change was evident in traditional da/dN fatigue crack growth. The data permits comparisons of the two alloys both with and without the HIP process.

  15. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    Science.gov (United States)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  16. Preparation of α-Al2O3 base ceramic coating on aluminum alloy via thermo-decomposition of diaspore

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The aim of this work is to describe the possibilities of preparing a corundum coating onaluminum alloy through in-situ chemical reaction at a relative low temperature. The transformationconditions of diaspore (β-AIOOH) to corundum (α-Al2O3 ) are studied using X-ray diffraction analy-sis. Temperature and heating time are two main factors influencing the transformation. Suitableheating parameters can lower the transformation temperature. On this basis, a new process isdeveloped to produce corundum ceramic coating on an aluminum alloy substrate. The phasecomposition and microstructure of the coating are studied using X-ray diffraction analysis andScanning Electron Microscopy. Abrasion properties of the coating are evaluated by ring-block tri-botester. The results show that it is feasible to obtain ceramic coatings on aluminum alloy sub-strates by means of thermo-decomposition of diaspore.

  17. The Effects of Ionized Gas Exposure on the Toughness and Fatigue Properties of Aluminum Alloys and Composites.

    Science.gov (United States)

    Zaat, Stephen Vincent

    The effects of an oxygen ionized gas from simulated space exposure on the toughness and fatigue properties of several aerospace aluminum alloys and aluminum composites have been analyzed. The test matrix consisted of four aluminum systems: the 6000 and 1100 series and two 8090 aluminum-lithium alloys. The test specimens were prepared as Charpy V-notched impact and disk-shaped compact fracture toughness specimens. A small specimen size is used for the compact tension specimens to facilitate exposure in a Radio Frequency (RF) Plasma Prep II unit. Radio frequency plasma, sometimes referred to as the "electrodeless plasma", is used in disassociative ionization of molecular oxygen to simulate high fluence, relatively low energy, low earth orbit (LEO) space atomic oxygen. The plasma reacts with the aluminum alloy systems and forms a thin scale of alumina a few microns thick. Monolayer sensitive Variable Angle Spectroscopic Ellipsometry (VASE) is used to determine the growth characteristics and effect on optical constants, the reflective index, n and absorption coefficient, k. Atomic Force Microscopy (AFM) was also employed to determine the effect of short exposure to the oxygen plasma environment. AFM indicates that sharp spikes of oxygen rich material are produced above the aluminum specimen surface resulting in stress concentrations with gradual roughing of the surface. After 10 years of simulated exposure, the increased roughness results in a 34% increase in the fatigue crack growth, da/dN, for the 6000 series; the crack growth rate of the aluminum-lithium material was increased about 28%. The results of instrumented Charpy V-notched impact specimens indicated that exposure reduced the energy for fracture initiation by 29%. Plane strain fracture toughness effects could not be established because the influence of oxygen was concentrated at the surface of the specimens.

  18. Composition and Performance of Nanostructured Zirconium Titanium Conversion Coating on Aluminum-Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Sheng-xue Yu

    2013-01-01

    Full Text Available Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF6 0.75 g·L−1, NaF 1.25 g·L−1, MgSO4 1.0 g/L, and tetra-n-butyl titanate (TBT 0.08 g·L−1. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM and scanning electron microscopy (SEM. Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS. Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is 9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.

  19. The Effect of Melt Conditioning on Segregation of Solute Elements and Nucleation of Aluminum Grains in a Twin Roll Cast Aluminum Alloy

    Science.gov (United States)

    Kim, KeeHyun

    2014-09-01

    An aluminum alloy was cast by a laboratory scale horizontal twin roll caster with or without melt conditioning by the intensive shearing prior to solidification and then examined by high-resolution electron microscopy. The combined twin roll casting process with solidification formed channels and induced centerline segregation without the conditioning. In comparison, the melt conditioning minimized the severe segregation on the surface as well as at the centerline. Furthermore, large amounts of solute elements were uniformly distributed along grain boundaries or interdendritic regions. Analytical electron microscopy detected a fine oxide particle or a fragmented aluminum particle particularly at the center region of one nucleated aluminum grain. In addition, large oxide particles of about 1 to 5 μm nucleated aluminum grains easily due to low undercooling necessary for the heterogeneous nucleation, whereas small oxides with the size of about 100 to 200 nm requiring large undercooling were pushed along the grain boundaries instead of contributing to the nucleation. The enhanced nucleation of aluminum grains and well-distributed solute atoms in the melt by the melt conditioning resulted in the minimization of macro- and micro-segregations and the formation of a uniform microstructure.

  20. Point Contact Andreev Reflection Measurement of the Spin Polarization of Ferromagnetic Alloy NiFeSb

    Institute of Scientific and Technical Information of China (English)

    李壮志; 陶宏杰; 闻海虎; 张铭; 柳祝红; 崔玉亭; 吴光恒

    2002-01-01

    We have studied the temperature-dependent and barrier-strength-dependent Andreev reflection tunnelling spectroscopy with point contacts consisting of the newly synthesized half-metallic alloy NiFeSb and a Nb tip. By fitting the data to the generalized Blonder-Tinkham-Klapwijk theory, a spin polarization P = 0.52 has been obtained.

  1. Density and solidiifcation feeding model of vacuum counter-pressure cast aluminum alloy under grade-pressuring conditions

    Institute of Scientific and Technical Information of China (English)

    Qing-song Yan; Huan Yu; Gang Lu; Bo-wen Xiong; Suai Xu

    2016-01-01

    The density of vacuum counter-pressure cast aluminum alloy samples under grade-pressuring condition was studied. The effect of grade pressure difference and time on the density of aluminum aloys was discussed, and the solidiifcation feeding model under grade-pressuring condition was established. The results indicate the grade-pressured solidiifcation feeding ability of vacuum counter-pressure casting mainly depends on grade pressure difference and time. With the increase of grade pressure difference, the density of al the aluminum aloy samples increases, and the trend of change in density from the pouring gate to the top location is first decreasing gradually and then increasing. In addition, in obtaining the maximum density, the optimal grade-pressuring time is different for samples with different wal thicknesses, and the solidiifcation time when the solid volume fraction of aluminum aloy reaches about 0.65 appears to be the optimal beginning time for grade-pressuring.

  2. Surface Characterizations of Fretting Fatigue Damage in Aluminum Alloy 7075-T6 Clamped Joints: The Beneficial Role of Ni–P Coatings

    Directory of Open Access Journals (Sweden)

    Reza H. Oskouei

    2016-02-01

    Full Text Available This paper aims to characterize the surface damage as a consequence of fretting fatigue in aluminum alloy 7075-T6 plates in double-lap bolted joints through XRD, surface profilometry, and SEM analyses. The main focus was on the surface roughness and chemical phase composition of the damaged zone along with the identification of fretting fatigue crack initiations over the surface of the material. The surface roughness of the fretted zone was found to increase when the joint was clamped with a higher tightening torque and tested under the same cyclic loading. Additionally, MgZn2 (η/ή precipitates and ZnO phase were found to form onto the surface of uncoated aluminum plate in the fretted and worn zones. The formation of the ZnO phase was understood to be a result of frictional heat induced between the surface of contacting uncoated Al 7075-T6 plates during cyclic loading and exposure to the air. The beneficial role of electroless nickel-phosphorous (Ni–P coatings in minimizing the fretting damage and thus improving the fretting fatigue life of the aluminum plates was also studied. The results showed that the surface roughness decreased by approximately 40% after applying Ni–P coatings to the Al 7075-T6 plates.

  3. Performance Comparison of Al–Ti Master Alloys with Different Microstructures in Grain Refinement of Commercial Purity Aluminum

    Directory of Open Access Journals (Sweden)

    Wanwu Ding

    2014-05-01

    Full Text Available Three types of Al–5Ti master alloys were synthesized by a method of thermal explosion reaction in pure molten aluminum. Performance comparison of Al–5Ti master alloy in grain refinement of commercial purity Al with different additions (0.6%, 1.0%, 1.6%, 2.0%, and 3.0% and holding time (10, 30, 60 and 120 min were investigated. The results show that Al–5Ti master alloy with blocky TiAl3 particles clearly has better refining efficiency than the master alloy with mixed TiAl3 particles and the master alloy with needle-like TiAl3 particles. The structures of master alloys, differing by sizes, morphologies and quantities of TiAl3 crystals, were found to affect the pattern of the grain refining properties with the holding time. The grain refinement effect was revealed to reduce markedly for master alloys with needle–like TiAl3 crystals and to show the further significant improvement at a longer holding time for the master alloy containing both larger needle–like and blocky TiAl3 particles. For the master alloy with finer blocky particles, the grain refining effect did not obviously decrease during the whole studied range of the holding time.

  4. Influence of process parameters on deep drawing of AA6111 aluminum alloy at elevated temperatures

    Institute of Scientific and Technical Information of China (English)

    马闻宇; 王宝雨; 傅垒; 周靖; 黄鸣东

    2015-01-01

    To gain a deep insight into the hot drawing process of aluminum alloy sheet, simulations of cylindrical cup drawing at elevated temperatures were carried out with experimental validation. The influence of four important process parameters, namely, punch velocity, blank holder force (BHF), friction coefficient and initial forming temperature of blank on drawing characteristics (i.e. minimum thickness and thickness deviation) was investigated with the help of design of experiments (DOE), analysis of variance (ANOVA) and analysis of mean (ANOM). Based on the results of ANOVA, it is shown that the blank holder force has the greatest influence on minimum thickness. The importance of punch velocity for thickness deviation is 44.35%followed by BHF of 24.88%, friction coefficient of 15.77%and initial forming temperature of blank of 14.995%. After determining the significance of each factor on forming characteristics, how the individual parameter affects characteristics was further analyzed by ANOM.

  5. Study of Composite Hardcoat Anodizing of Aluminum Alloy 6063 and Its Friction Behaviors

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-yong; ZHANG Hui-chen; GAO Xue-min; LIU Wei; SHI Ya-qin

    2004-01-01

    A composite hard-anodized coating containing micro PTFE (polytetrafluoroethylene) particles on aluminum alloy 6063 was produced by adding micro PTFE particles into the traditional hardcoat anodizing solution. The size of the PTFE particles is around 2 μ m in diameter and the content of the PTFE particles in the composite coating is within 2%-3% by area percentage. Thickness of the composite coating can reach up to 70 μ m after one hour's anodizing. Surface hardness of the composite coating is between 400-480 HV0.1. The average friction coefficient of the composite coating against steel under dry friction test is 0.11, which is 17% lower than that obtained by traditional hardcoat anodizing.

  6. Influence of material modeling on earing prediction in cup drawing of AA3104 aluminum alloy sheet

    Science.gov (United States)

    Fukumasu, H.; Kuwabara, T.; Takizawa, H.

    2016-08-01

    In-plane biaxial tension and combined tension-compression tests are carried out for AA3104 aluminum alloy sheets. Linear stress paths are applied to cruciform specimens to measure the contours of plastic work in the stress space and the directions of plastic strain rates at each stress path. Coefficients α 1- α 8 and exponent M of the Yld2000-2d yield function are determined to minimize the mean square error of the analytical yield locus from a measured work contour. The values of the weighting coefficients in the evaluation of the error are varied to check the effect of a specific stress state on the earing behavior. The effects of the combinations of the weighting coefficients on the accuracy of earing prediction in the cup drawing process are discussed.

  7. Microstructure, Mechanical Properties, and Texture Evolution of Aluminum Alloy 7005 by Accumulative Roll Bonding

    Science.gov (United States)

    Xie, Hu; Wang, M. P.; Chen, Wei; Jia, Yanlin

    2016-03-01

    In the present work, the accumulative roll bonding process was carried out on a 7005 aluminum alloy sheet to six passes. The microstructure and texture evolution was investigated by transmission electron microscope, electron backscatter diffraction analysis, and x-ray texture goniometer. With the increase of ARB passes, the microstructure was refined and the fraction of high angle boundaries increased. The hardness of different ARB process specimens was measured and showed that as the ARB passes increased, the hardness rose obviously. The tensile strength of 6 passes reaches 423.4 MPa and the elongation is 4.6%. The material is strongly textured where individual layers possess typical FCC rolling texture components and the variation of each texture is different. This is attributed to the microstructure evolution during the ARB process.

  8. Role of Laser Cladding Parameters in Composite Coating (Al-SiC) on Aluminum Alloy

    Science.gov (United States)

    Riquelme, Ainhoa; Escalera-Rodriguez, María Dolores; Rodrigo, Pilar; Rams, Joaquin

    2016-08-01

    The effect of the different control parameters on the laser cladding fabrication of Al/SiCp composite coatings on AA6082 aluminum alloy was analyzed. A high-power diode laser was used, and the laser control parameters were optimized to maximize the size (height and width) of the coating and the substrate-coating interface quality, as well as to minimize the melted zone depth. The Taguchi DOE method was applied using a L18 to reduce the number of experiments from 81 to only 18 experiments. Main effects, signal-noise ratio and analysis of variance were used to evaluate the effect of these parameters in the characteristics of the coating and to determine their optimum values. The influence of four control parameters was evaluated: (1) laser power, (2) scanning speed, (3) focal condition, and (4) powder feed ratio. Confirmation test with the optimal control parameters was carried out to evaluate the Taguchi method's effectivity.

  9. Influence of quench rate and microstructure on bendability of AA6016 aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Castany, P., E-mail: philippe.castany@insa-rennes.fr [Laboratoire de Metallurgie Mecanique, Institut des Materiaux, Station 12, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Diologent, F.; Rossoll, A. [Laboratoire de Metallurgie Mecanique, Institut des Materiaux, Station 12, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Despois, J.-F.; Bezencon, C. [Novelis Switzerland SA, 3960 Sierre (Switzerland); Mortensen, A., E-mail: andreas.mortensen@epfl.ch [Laboratoire de Metallurgie Mecanique, Institut des Materiaux, Station 12, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)

    2013-01-01

    The influence of the quench rate after solution treatment on the bendability of AA6016 aluminum alloy sheets was investigated. Crack initiation during bending tests is found to be independent of quench rate whereas crack propagation is decreased after rapid quenching. A quantitative analysis of microstructures was carried out by transmission electron microscopy, focusing on grain boundary precipitates to correlate bending properties with microstructure. Crack initiation occurs by voiding at large micron-size intermetallic AlFeSi particles in shear bands, as previously proposed in the literature. Rapid quenching promotes the formation along grain boundaries of spherical Mg{sub 2}Si precipitates to the detriment of elongated Si precipitates that dominate after slow cooling. These Si grain boundary precipitates affect micro-voiding processes that drive crack propagation, which explains the observed dependence of the extent of cracking on quench rate. The grain boundary precipitate density has on the other hand no effect on crack initiation or propagation.

  10. 3D Stochastic Modeling of Grain Structure for Aluminum Alloy Casting

    Institute of Scientific and Technical Information of China (English)

    Qingyan XU; Weiming FENG; Baicheng LIU

    2003-01-01

    A 3D stochastic modeling was carried out to simulate the dendritic grains during solidification of aluminum alloys,including time-dependent calculations for temperature field, solute redistribution in liquid, curvature of the dendritictip, and growth anisotropy. The nucleation process was treated by continuous nucleation. A 3D simplified grainshape model was established to represent the equiaxed dendritic grain. Based on the Cellular Automaton method,a grain growth model was proposed to capture the neighbor cells of the nucleated cell. During growing, each graincontinues to capture the nearest neighbor cells to form the final shape. When a neighbor cell was captured by othergrains, the grain growth along this direction would be stopped. Three-dimensional calculations were performed tosimulate the evolution of dendritic grain. In order to verify the modeling results, the predictions were compared withthe observation on samples cast in the sand mold and the metal mold.

  11. Effect of magnesium in aluminum alloys on characteristics of microarc oxidation coatings

    Institute of Scientific and Technical Information of China (English)

    LIU Yao-hui; LI Song; YU Si-rong; ZHU Xian-yong; XU Bai-ming

    2006-01-01

    Microarc oxidation(MAO) coatings were prepared on the surface of aluminum alloys with different contents of magnesium. The morphologies and surface roughness of the coatings were characterized by Confocal laser scanning microscopy(CLSM). Phase and chemical composition of the MAO coatings were analyzed by X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The experimental results show that the coatings formed on different substrates have two-layer morphologies and are mainly composed of Al2O3 and Al-Si-O phases. In addition, the content of Al2O3 increases with increasing the content of magnesium. XPS results prove that magnesium from substrate indeed participates in the MAO process and is incorporated into the coating in the form of MgO. The coating formed on Al-3Mg substrate has the smallest mass loss and the lowest friction coefficient of 0.17-0.19.

  12. Analysis of Acoustic Emission Signal by Fractal Theory in Aluminum Alloy Spot Welding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The relation between acoustic emission signal and nugget during aluminum alloy spot welding was investigated in order to evaluate spot welding quality. Due to the nonlinearity of the signals, fractal theory was utilized to quantitatively describe the characteristics of the signals instead of classical Euclidean geometry which cannot describe the acoustic emission signal accurately. Through experiments and computing, the box counting dimension is found distinct from other acoustic emission signals and is a better approach to discriminating weld nugget stages. Results show that fractal dimensions increase from 1.51 to 1.78,and they are related to nugget areas added from non-fusion to over-heated nugget.And the box counting dimension can effectively evaluate the quality of the nugget in the spot welding and can be applied with current, displace, and other spot welding parameters.

  13. Identification of acoustic emission signal in aluminum alloys spot welding based on fractal theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The acoustic emission signal of aluminum alloys spot welding includes the information of forming nugget and is one of the important parameters in the quality control. Due to the nonlinearity of the signals, classic Euclidean geometry can not be applied to depict exactly. The fractal theory is implemented to quantitatively describe the characteristics of the acoustic emission signals. The experiment and calculation results show that the box counting dimension of acoustic emission signal, between 1 and 2, are distinctive from different nugget areas in AC spot welding. It is proved that box counting dimension is an effective characteristic parameter to evaluate spot welding quality. In addition, fractal theory can also be applied in other spot welding parameters, such as voltage, current, electrode force and so on, for the purpose of recognizing the spot welding quality.

  14. Friction stir spot welding of 2024-T3 aluminum alloy with SiC nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Paidar, Moslem; Sarab, Mahsa Laali [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-01-15

    In this study, the Friction stir spot welding (FSSW) of 2024-T3 aluminum alloy with 1.6 mm thickness was investigated. The effects of the silicon carbide (SiC) nanoparticles on the metallurgical and mechanical properties were discussed. The effects of particles on tension shear and wear tests were also investigated. The process was conducted at a constant rotational speed of 1000 rpm. Results showed that adding SiC nanoparticles to the weld during FSSW had a major effect on the mechanical properties. In fact, the addition of nanoparticles as barriers prevented grain growth in the Stir zone (SZ). The data obtained in the tensile-shear and wear tests showed that tensile-shear load and wear resistance increased with the addition of SiC nanoparticles, which was attributed to the fine grain size produced in the SZ.

  15. The microstructural evolution of friction stir welded AA6082-T6 aluminum alloy during cyclic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, A.S., E-mail: atef.hamada@oulu.fi [Centre for Advanced Steels Research, University of Oulu, P.O. Box 4200, FI-90014 Oulu (Finland); Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez University, Suez 43721 (Egypt); Järvenpää, A. [Oulu Southern Institute, University of Oulu, Pajatie 5, FI-85500 Nivala (Finland); Ahmed, M.M.Z. [Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez University, Suez 43721 (Egypt); Jaskari, M. [Oulu Southern Institute, University of Oulu, Pajatie 5, FI-85500 Nivala (Finland); Wynne, B.P. [Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Porter, D.A.; Karjalainen, L.P. [Centre for Advanced Steels Research, University of Oulu, P.O. Box 4200, FI-90014 Oulu (Finland)

    2015-08-26

    The fatigue behavior of a thick section friction stir welded AA6082-T6 aluminum alloy was studied to compare damage mechanisms in the weld zone and the base metal. Fully reversed tension–compression strain-controlled fatigue tests were conducted to determine the cyclic stress response and stored energy to failure. Microstructure evolution during cyclic straining was followed using secondary electron imaging and electron backscatter diffraction in a scanning electron microscope. Fatigue cracking along grain boundaries and the formation of slip bands were observed to be the fatigue-induced microstructural features in the friction-stir-welded structure. In the base metal, micron-sized particles led to particle-induced cracking.

  16. Thermal Management in Friction-Stir Welding of Precipitation-Hardening Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Piyush; Reynolds, Anthony

    2015-05-25

    Process design and implementation in FSW is mostly dependent on empirical information gathered through experience. Basic science of friction stir welding and processing can only be complete when fundamental interrelationships between process control parameters and response variables and resulting weld microstructure and properties are established to a reasonable extent. It is known that primary process control parameters like tool rotation and translation rate and forge axis force have complicated and interactive relationships to the process response variables such as peak temperature, time at temperature etc. Of primary influence to the other process response parameters are temperature and its gradient at the deformation and heat affected zones. Through review of pertinent works in the literature and some experimental results from boundary condition work performed in precipitation hardening aluminum alloys this paper will partially elucidate the nature and effects of temperature transients caused by variation of thermal boundaries in Friction Stir Welding.

  17. Strain hardening and damage in 6xxx series aluminum alloy friction stir welds

    DEFF Research Database (Denmark)

    Simar, Aude; Nielsen, Kim Lau; de Meester, Bruno;

    2010-01-01

    A friction stir weld in 6005A-T6 aluminum alloy has been prepared and analyzed by micro-hardness measurements, tensile testing and scanning electron microscopy (SEM). The locations of the various weld zones were determined by micro-hardness indentation measurements. The flow behavior of the various...... zones of the weld was extracted using micro-tensile specimens cut out parallel to the welding direction. The measured material properties and weld topology were then introduced in a fully coupled micro-mechanical finite element model, accounting for nucleation and growth of voids as well as void shape...... evolution. The model shows satisfactory preliminary results in predicting the tensile behaviour of the weld and the true strain at fracture....

  18. Parametric optimization of friction stir welding process of age hardenable aluminum alloys-ANFIS modeling

    Institute of Scientific and Technical Information of China (English)

    D Vijayan; V Seshagiri Rao

    2016-01-01

    A comparative approach was performed between the response surface method (RSM) and the adaptive neuro-fuzzy inference system (ANFIS) to enhance the tensile properties, including the ultimate tensile strength and the tensile elongation, of friction stir welded age hardenable AA6061 and AA2024 aluminum alloys. The effects of the welding parameters, namely the tool rotational speed, welding speed, axial load and pin profile, on the ultimate tensile strength and the tensile elongation were analyzed using a three-level, four-factor Box-Behnken experimental design. The developed design was utilized to train the ANFIS models. The predictive capabilities of RSM and ANFIS were compared based on the root mean square error, the mean absolute error, and the correlation coefficient based on the obtained data set. The results demonstrate that the developed ANFIS models are more effective than the RSM model.

  19. Manufacturing of aluminum alloy ultra-thick plates by multidirectional forging and subsequent rolling

    Institute of Scientific and Technical Information of China (English)

    张辉; 林高用; 彭大暑; 杨立斌; 林启权

    2002-01-01

    A combinatory large deformation model of multidirectional forging and subsequent rolling was proposed for producing high performance aluminum alloy ultra-thick plates.The results show that fine-grain (2~3 μm) structures were obtained when total deformation coefficient λ =32 at 250~350 ℃ under a strain rate of about 0.1 s-1.The development of fine-grained structure can be characterized by the formation of strain-induced high energy dislocation and then transforms into new grain under large deformation at moderate temperature.The very fine secondary particles formed during large deformation play important role in retain the stability of the fine-grained structures.

  20. Establishment of constitutive relationship model for 2519 aluminum alloy based on BP artificial neural network

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-quan; PENG Da-shu; ZHU Yuan-zhi

    2005-01-01

    An isothermal compressive experiment using Gleeble 1500 thermal simulator was studied to acquire flow stress at different deformation temperatures, strains and strain rates. The artificial neural networks with the error back propagation(BP) algorithm was used to establish constitutive model of 2519 aluminum alloy based on the experiment data. The model results show that the systematical error is small(δ=3.3%) when the value of objective function is 0.2, the number of nodes in the hidden layer is 5 and the learning rate is 0.1. Flow stresses of the material under various thermodynamic conditions are predicted by the neural network model, and the predicted results correspond with the experimental results. A knowledge-based constitutive relation model is developed.