Sample records for strength wrought aluminum

  1. Modeling of Alternative Compositions of Recycled Wrought Aluminum Alloys

    Kevorkijan, Varužan


    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

  2. The Elastic Constants for Wrought Aluminum Alloys

    Templin, R L; Hartmann, E C


    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.

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

    Kevorkjjan, Varužan


    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.

  4. Influence of heat treatment on tribological behaviors of novel wrought aluminum bronze

    张卫文; 倪东惠; 夏伟; 邱诚; 陈维平


    Influence of heat treatment on mechanica l properties and tribologica l behaviors of Ti and B modified wrought aluminum bronze were studied. The res ults show that different strength and plasticity combination of the alloy after solu tion treatment can be obtained by adjusting the ageing temperature. When aged at 45 0 ℃, the tensile strength σb, yield strength σ0.2, elongatio n δ and hardness of the alloy are 1 050 MPa, 780 MPa, 4.5%, HB282, respectively. When aged at 650 ℃, those of the alloy are 905 MPa, 600 MPa, 12%, HB232, respectively. Under boundary l ubri cation condition with pressure above 22.2 MPa, alloy with low temperature agei ng has the best wear property. However, under the condition involving impact or sh ock loading, alloy with high temperature ageing is preferable. If the load is no t heavy, the alloy under extrusion state is favorable for wear-resisting parts.

  5. Microstructure characteristics and mechanical properties of rheoformed wrought aluminum alloy 2024

    GUO Hong-min; YANG Xiang-jie; ZHANG Meng


    The microstructure characteristics and mechanical properties of 2024 wrought aluminum alloy produced by a new rheoforming technique under as-cast and optimized heat treatment conditions were investigated. The present rheoforming combined the independently developed rheocasting process, named as LSPSF (low superheat pouring with a shear field) process, and the existing squeeze casting process. The experimental results show that LSPSF can be used to prepare sound semi-solid slurry within 25s to fully meet the production rate of squeeze casting. The primary α (Al) presents in mean equivalent diameter of 69μm and shape factor of 0.76, and features zero-entrapped eutectics. Compared with conventional squeeze casting, the present LSPSF rheoforming can improve the microstructures and mechanical properties. An optimized heat treatment results in substantial reduction of microsegregation and significant improvement of mechanical properties, such as yield strength of 321MPa, ultimate tensile strength of 428MPa and elongation of 12%.

  6. Preparation of semi-solid slurry containing fine and globular particles for wrought aluminum alloy 2024


    The semi-solid slurry of wrought aluminum alloy 2024 was prepared by a well developed rheocasting process, low superheat pouring with shearing field(LSPSF). The appreciate combination of pouring temperature and rotation speed of barrel, can give rise to a transition of the growth morphology of primary α(Al) from coarse-dendritic to coarse-particle-like and further to fine-globular. The combined effects of both localized rapid cooling and vigorous mixing during the initial stage of solidification can enhance wall nucleation and nuclei survival, which leads to the formation of fine-globular primary α(Al). By using semi-solid slurry prepared by LSPSF, direct squeeze cast cup-shaped component with improved mechanical properties such as yield strength of 198MPa, ultimate tensile strength of 306 MPa and elongation of 10.4%, can be obtained.


    X.T. Liu; J.Z. Cui


    Microstructure evolution of wrought aluminum alloy extruded rods and the mechanism of liquid phase formation during reheating were investigated. And the relation between the volume fraction of liquid phase and the recrystallization microstructure was proposed. The results show that increase in reheating temperature and time can augment the volume fraction of liquid phase and accelerate the grain spheroidization, as a result of which the requirement of semi-solid forming can be satisfied. Due to the higher aberration energy of grain boundary, the melting point is lowered as a result of the easy diffusion of atoms. At higher reheating temperature the grain boundary melts, the growth of the recrystallized grain is inhibited and the grain is refined. The composition of the low melt-point phase along the recrystallized grains was determined using EDS. It can be seen from the experimental results that when the extrusion rod of the wrought aluminum alloy is reheated at 610℃ for 20min, perfect fine equiaxial grains can be obtained, the average grain size is about 66.34μm and the volume fraction of solid phase is about 68%.

  8. Microstructure characteristics and solidification behavior of wrought aluminum alloy 2024 rheo-diecast with self-inoculation method

    Li Yanlei


    Full Text Available One important problem in casting wrought aluminum alloys is the high tendency to the formation of hot tears in the solidification process. By using semi-solid metal (SSM processing, the hot tearing tendency of alloys can be minimized during casting. In the present research, the semi-solid slurry of wrought aluminum alloy 2024 was firstly prepared with a novel self-inoculation method (SIM, and then the microstructure characteristics of the semi-solid slurry and the rheo-diecastings cast with the semi-solid slurry were investigated. The results indicate that finer and more uniform globular primary α-Al particles can be obtained when the semi-solid slurry are isothermally held for a short period within the semi-solid temperature range, and the primary α-Al particles without entrapped liquid are uniformly fine, globular grains in the rheo-diecastings. The holding temperature and time affect the solid fraction, particle size, and shape factor. After the semi-solid slurry is held at 625 ℃ for 3 min and 5 min, the optimal values for the average equivalent diameter are 70.80 μm and 74.15 μm, and for the shape factor are 1.32 and 1.42, respectively. The solidification process of the rheo-diecastings is composed of the following two distinct stages: primary solidification process and secondary solidification process. The secondary solidification process consists further of the following three stages: (1 direct growth of secondary primary (α2 phase from the surface of the primary α-Al phase particles without re-nucleation, (2 independent nucleation and growth of α3 phase from the residual liquid, and (3 eutectic reaction at the end.

  9. Friction Stir Welding in Wrought and Cast Aluminum Alloys: Heat Transfer Modeling and Thermal History Analysis

    Pan, Yi; Lados, Diana A.


    Friction stir welding (FSW) is a technique that can be used for materials joining and local microstructural refinement. Owing to the solid-state character of the process, FSW has significant advantages over traditional fusion welding, including reduced part distortion and overheating. In this study, a novel heat transfer model was developed to predict weld temperature distributions and quantify peak temperatures under various combinations of processing parameters for different wrought and cast Al alloys. Specifically, an analytical analysis was first developed to characterize and predict heat generation rate within the weld nugget, and then a two-dimensional (2D) numerical simulation was performed to evaluate the temperature distribution in the weld cross-section and top-view planes. A further three-dimensional (3D) simulation was developed based on the heat generation analysis. The model was validated by measuring actual temperatures near the weld nugget using thermocouples, and good agreement was obtained for all studied materials and conditions.

  10. Monotonic and cyclic deformation behavior of MIG-CMT welded and heat-treated joints of aluminum cast and wrought alloys

    Kantehm, Matthias; Soeker, Marcus; Krupp, Ulrich; Michels, Wilhelm [Faculty of Engineering and Computer Science, Institute of Materials Design and Structural Integrity, University of Applied Sciences Osnabrueck, 49009 Osnabrueck (Germany)


    While the fatigue behavior of die cast aluminum as well as welded aluminum wrought alloys have been subject of several studies, no systematic work has been carried out on hybrid structures made as a combination of welded sand castings and wrought alloys. Aim of the present study is to correlate the monotonic and cyclic deformation behavior of thin sheet welded joints with the microstructure in the heat affected zone of the material combination sand cast EN AC-Al Si7Mg0.3 and wrought alloy EN AW-Al Si1MgMn (EN AW-6082). The metal sheets were welded using a metal inert gas cold metal transfer process under variation of the welding gap, the heat treatment parameters, as well as the surface finishes. It was demonstrated by Woehler diagrams based on bending fatigue tests that the fatigue life could be increased for the welded and heat treated specimens as compared to the as-received cast specimens. By means of optical microscopy this effect was attributed to microstructural changes due to the optimized welding and heat treatment process. A detailed analysis of the mechanical tests was possible by the application of an optical 3D strain analysis. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Classification of wrought aluminum alloys by Artificial Neural Networks evaluation of Laser Induced Breakdown Spectroscopy spectra from aluminum scrap samples

    Campanella, B.; Grifoni, E.; Legnaioli, S.; Lorenzetti, G.; Pagnotta, S.; Sorrentino, F.; Palleschi, V.


    Every year throughout the world > 50 million vehicles reach the end of their life, producing millions of tons of automotive waste. The current strategies for the separation of the non-ferrous waste fraction, contain mainly aluminum, magnesium, zinc and copper alloys, involve high investment and operational costs, and pose environmental concerns. The European project SHREDDERSORT, in which our research group was actively involved, aimed to overcome this issue by developing a new dry sorting technology for the shredding of non-ferrous automotive wastes. This work represents one step of the complex SHREDDERSORT project, dedicated to the development of a strategy based on Laser Induced Breakdown Spectroscopy (LIBS) for the sorting of light alloys. LIBS was here applied in laboratory for the analysis of stationary aluminum shredder samples. To process the LIBS spectra a methodological approach based on artificial neural networks was used. Although separation could in principle be based on simple emission line ratios, the neural networks approach enables more reproducible results, which can accommodate the unavoidable signal variations due to the low intrinsic reproducibility of the LIBS systems. The neural network separated samples into different clusters and estimates their elemental concentrations.

  12. Study on the rheoformability of semi-solid 7075 wrought aluminum alloy using seed process =

    Zhao, Qinfu

    Semisolid metal forming is becoming more and more attractive in the foundry industry due to its low cost and easy operation to produce high quality near-net-shape components. Over the past years, semisolid forming technique is mainly applied on the casting aluminum alloys due to their superior castability because of low melting temperature and viscosity. In semisolid forming field, thixoforming has been majorly used which involves of reheating the billet into semisolid state followed by casting process. Rheocasting is a more economic semisolid processing compared to thixoforming, which the semisolid billet is produced directly from liquid phase. The SEED process is one of reliable rheocasting techniques to produce high quality semisolid billets. To produce high quality semisolid billets, their unique rheological properties have been the most important issue need to be fully investigated. The aim of present project is to produce high quality semisolid AA7075 billets by SEED process and analyze their rheological properties under various process conditions. The effect of the SEED processing parameters and grain refiners on the semisolid microstructure and rheoformability were investigated. The deformation and rheological behavior of the semisolid billets of AA7075 base and its grain-refined alloys were studied using parallel-plate viscometer. In the first part, the evolution of liquid fraction to temperature of semisolid AA7075 alloy was investigated using Differential Scanning Calorimetry (DSC). It was found that the liquidus and solidus temperature of AA7075 alloy were 631 °C and 490°C respectively. And the corresponding temperatures of solid fraction of 40% and 60% were 622°C and 610°C, which was recognized as the temperature window for semisolid forming of this alloy. In the second part, the semisolid slurries were rheocasted using SEED technology and the effect of the SEED process parameters like swirling frequency and demolding temperature on evolution of

  13. Friction Stir Welding in Wrought and Cast Aluminum Alloys: Weld Quality Evaluation and Effects of Processing Parameters on Microstructure and Mechanical Properties

    Pan, Yi; Lados, Diana A.


    Friction stir welding (FSW) is a solid-state process widely used for joining similar and dissimilar materials for critical applications in the transportation sector. Understanding the effects of the process on microstructure and mechanical properties is critical in design for structural integrity. In this study, four aluminum alloy systems (wrought 6061-T651 and cast A356, 319, and A390) were processed in both as-fabricated and pre-weld heat-treated (T6) conditions using various processing parameters. The effects of processing and heat treatment on the resulting microstructures, macro-/micro-hardness, and tensile properties were systematically investigated and mechanistically correlated to changes in grain size, characteristic phases, and strengthening precipitates. Tensile tests were performed at room temperature both along and across the welding zones. A new method able to evaluate weld quality (using a weld quality index) was developed based on the stress concentration calculated under tensile loading. Optimum processing parameter domains that provide both defect-free welds and good mechanical properties were determined for each alloy and associated with the thermal history of the process. These results were further related to characteristic microstructural features, which can be used for component design and materials/process optimization.

  14. Friction Stir Welding in Wrought and Cast Aluminum Alloys: Weld Quality Evaluation and Effects of Processing Parameters on Microstructure and Mechanical Properties

    Pan, Yi; Lados, Diana A.


    Friction stir welding (FSW) is a solid-state process widely used for joining similar and dissimilar materials for critical applications in the transportation sector. Understanding the effects of the process on microstructure and mechanical properties is critical in design for structural integrity. In this study, four aluminum alloy systems (wrought 6061-T651 and cast A356, 319, and A390) were processed in both as-fabricated and pre-weld heat-treated (T6) conditions using various processing parameters. The effects of processing and heat treatment on the resulting microstructures, macro-/micro-hardness, and tensile properties were systematically investigated and mechanistically correlated to changes in grain size, characteristic phases, and strengthening precipitates. Tensile tests were performed at room temperature both along and across the welding zones. A new method able to evaluate weld quality (using a weld quality index) was developed based on the stress concentration calculated under tensile loading. Optimum processing parameter domains that provide both defect-free welds and good mechanical properties were determined for each alloy and associated with the thermal history of the process. These results were further related to characteristic microstructural features, which can be used for component design and materials/process optimization.

  15. Aluminum/steel wire composite plates exhibit high tensile strength


    Composite plate of fine steel wires imbedded in an aluminum alloy matrix results in a lightweight material with high tensile strength. Plates have been prepared having the strength of titanium with only 85 percent of its density.

  16. Elevated temperature strength, aging response and creep of aluminum matrix composites

    Bhagat, R.B.; Amateau, M.F.; House, M.B.; Meinert, K.C.; Nisson, P. (Pennsylvania State University, State College (United States))


    The effect of reinforcement on the high-temperature performance of aluminum matrix composites was investigated using samples of 6061 aluminum alloy reinforced with planar-random graphite fibers, SiC whiskers, or alumina particles, which were aged at 150 and 200 C for up to 500 hrs. As indicated by the results of microhardness tests, all specimens exhibited accelerated aging response, with the response depending on the characteristics of the reinforcement. Both the graphite-fiber- and SiC-whisker-reinforced composites showed a substantially increased strengths over that of the wrought 6061 Al at all temperatures. The graphite-fiber- and the SiC-whisker-reinforced composites were found to retain their tensile strength and stiffness in the overaged condition of the matrix. The whisker-reinforced composite showed significant resistance to creep at temperatures between 232 and 350 C under stresses of up to 100 MPa, while the particulate composite had a moderate increase in creep resistance. 51 refs.

  17. Current Situation and Development Trend of Saw Machine for Wrought Aluminum and Aluminum Alloy Ingot/Billet%变形铝及铝合金铸锭锯切机现状及发展趋势



    通过对变形铝及铝加工行业锯切机使用现状的描述,介绍了几种常见的锯切形式和锯头配置方式,并通过对每种特点的分析,给出各自的适用场合;最后指出在工业4.0大背景下,自动化、智能化、系统化是其发展的趋势。%Based on the review of application of saw machine in wrought aluminum and aluminum processing industry,the paper presented some common types of saws and configuration of saw heads,it accordingly described applicable situations through the characteristic analysis;it pointed out that automation, intel ectualization and systematization should be the development trend for saw machine in the context of Industry 4.0.

  18. Analysis of the potential for new automotive uses of wrought magnesium

    Gaines, L.; Cuenca, R.; Wu, S. [Argonne National Lab., IL (United States); Stodolsky, F. [Argonne National Lab., IL (United States)]|[Argonne National Lab., Washington, DC (United States)


    The Center for Transportation Research at Argonne National Laboratory has performed a study for the Lightweight Materials Program within the US Department of Energy`s Office of Transportation Materials to evaluate the suitability of wrought magnesium and its alloys to replace steel or aluminum for automotive structural and sheet applications. Vehicle weight reduction is one of the major means available for improving automotive fuel efficiency. Although high-strength steels, Al, and polymers are already being used to achieve significant weight reductions, substantial additional weight reductions could be achieved by increased use of Mg (whose density is less than one-fourth that of steel and only two-thirds that of Al). This study shows that Mg sheet could be used in automotive body nonstructural and semistructural applications, whereas extrusions could be used in such structural applications as spaceframes. The primary barrier to such uses of wrought Mg is high cost.

  19. High Strength Discontinuously Reinforced Aluminum For Rocket Applications

    Pandey, A. B.; Shah, S. R.; Shadoan, M.


    This study presents results on the development of a new aluminum alloy with very high strength and ductility. Five compositions of Al-Mg-Sc-Gd-Zr alloy were selected for this purpose. These alloys were also reinforced with 15 volume percent silicon-carbide and boron-carbide particles to produce Discontinuously Reinforced Aluminum (DRA) materials. Matrix alloys and DRA were processed using a powder metallurgy process. The helium gas atomization produced very fine powder with cellular-dentritic microstructure. The microstructure of matrix alloys showed fine Al3Sc based precipitate which provides significant strengthening in these alloys. DRA showed uniform distribution of reinforcement in aluminum matrix. DRA materials were tested at -320 F, 75 F in air and 7S F in gaseous hydrogen environments and matrix alloys were tested at 75 F in air. DRA showed high strengths in the range of 89-111 ksi (614-697 MPa) depending on alloy compositions and test environments. Matrix alloys had a good combination of strength, 84-89 ksi (579-621 MPa) and ductility, 4.5-6.5%. The properties of these materials can further be improved by proper control of processing parameters.

  20. Overheating temperature of 7B04 high strength aluminum alloy

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


    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.

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

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


    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.

  2. Analysis of peel strength of consisting of an aluminum sheet, anodic aluminum oxide and a copper foil laminate composite

    Shin, Hyeong-Won; Lee, Hyo-Soo; Jung, Seung-Boo


    Laminate composites consisting of an aluminum sheet, anodic aluminum oxide, and copper foil have been used as heat-spreader materials for high-power light-emitting diodes (LEDs). These composites are comparable to the conventional structure comprising an aluminum sheet, epoxy adhesives, and copper foil. The peel strength between the copper foil and anodic aluminum oxide should be more than 1.0 kgf/cm in order to be applied in high-power LED products. We investigated the effect of the anodic aluminum oxide morphology and heat-treatment conditions on the peel strength of the composites. We formed an anodic aluminum oxide layer on a 99.999% pure aluminum sheet using electrochemical anodization. A Ti/Cu seed layer was formed using the sputtering direct bonding copper process in order to form a copper circuit layer on the anodic aluminum oxide layer by electroplating. The developed heat spreader, composed of an aluminum layer, anodic aluminum oxide, and a copper circuit layer, showed peel strengths ranging from 1.05 to 3.45 kgf/cm, which is very suitable for high-power LED applications.

  3. 49 CFR 587.15 - Verification of aluminum honeycomb crush strength.


    ... 49 Transportation 7 2010-10-01 2010-10-01 false Verification of aluminum honeycomb crush strength... Deformable Barrier § 587.15 Verification of aluminum honeycomb crush strength. The following procedure is used to ascertain the crush strength of the main honeycomb block and the bumper element honeycomb,...

  4. Weld geometry strength effect in 2219-T87 aluminum

    Nunes, A. C., Jr.; Novak, H. L.; Mcilwain, M. C.


    A theory of the effect of geometry on the mechanical properties of a butt weld joint is worked out based upon the soft interlayer weld model. Tensile tests of 45 TIG butt welds and 6 EB beads-on-plate in 1/4-in. 2219-T87 aluminum plate made under a wide range of heat sink and power input conditions are analyzed using this theory. The analysis indicates that purely geometrical effects dominate in determining variations in weld joint strength with heat sink and power input. Variations in weld dimensions with cooling rate are significant as well as with power input. Weld size is suggested as a better indicator of the condition of a weld joint than energy input.


    Mechanical properties of wrought tungsten vol. II. Creep rupture test data from 1500 to 5000 F, and tensile test data from room temperature to 5000 F at various strain rates for tungsten sheet material.

  6. Brazing process provides high-strength bond between aluminum and stainless steel

    Huschke, E. G., Jr.; Nord, D. B.


    Brazing process uses vapor-deposited titanium and an aluminum-zirconium-silicon alloy to prevent formation of brittle intermetallic compounds in stainless steel and aluminum bonding. Joints formed by this process maintain their high strength, corrosion resistance, and hermetic sealing properties.

  7. Mechanical behaviour of aluminum screws. Pt. 2. Cyclic behaviour; Tragfaehigkeit von Aluminiumschrauben. T. 2. Zyklische Tragfaehigkeit

    Weber, J.O. [Deutscher Schraubenverband, Hagen (Germany); Marx, T. [Adam Opel AG, Ruesselsheim (Germany); Berger, C. [Zentrum fuer Konstruktionswerkstoffe, Institut fuer Werkstoffkunde der Technischen Universitaet Darmstadt (Germany); Arz, U.


    This article is the second part of a description of the mechanical behaviour of aluminum screws. The first part describes the mechanical behaviour under static conditions, while the second part details the cyclic behaviour. An overview of the influences to the cyclic behaviour of high strength aluminum screws made of the wrought alloys EN AW 6013, EN AW 6056 and EN AW 7075 is given. In some cases values for EN AW 6082 are presented.

  8. Development of high-strength, low-cost wrought Mg–2.0 mass% Zn alloy with high Mn content

    Fusheng. Pan


    Full Text Available Mg–Zn–Mn-based alloys have received considerable attention because of their high creep resistance, strength, and good corrosion resistance. The alloying element Mn in Mg–Zn-based alloys is commonly less than 1 wt%. In the present study, the effect of high Mn content (1 wt% and 2 wt% on the microstructures and mechanical properties of Mg–2Zn–0.3Sr extruded alloy was investigated. The results revealed that the high Mn content significantly increased the ultimate tensile strength, tensile yield strength, compress yield strength, and yield asymmetry of the alloy without affecting its ductility. The dynamically recrystallized (DRXed grains of Mg–2Zn–0.3Sr were remarkably refined because of the large amount of fine Mn precipitates in the homogenized alloy. The improved strengths were mainly attributed to the fine DRXed grains according to the Hall–Petch effect and to the large amount of spherical and Mn precipitates through the precipitation and dispersion strengthening. The fine DRXed grains and numerous Mn precipitates effectively suppressed the extension twining, substantially enhanced the compress yield strength, and resulted in improved anisotropy.

  9. Higher Strength, Lighter Weight Aluminum Spacecraft Structures Project

    National Aeronautics and Space Administration — This SBIR Phase I program proposes to develop a bulk processing technology for producing ultra fine grain (UFG) aluminum alloy structures. The goal is to demonstrate...

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

    Kittima Sillapasa


    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.

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

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


    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.

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

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


    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.

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

    H. S. Zhang


    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.

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

    Lee, Jonathan A.


    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.

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

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


    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.

  16. strength and ductility of forged 1200 aluminum alloy reinforced with ...


    Results show that forged composites with 106μm had a tensile strength .... W. Ag. Sn. Co. % Composition 0.243 0.004 0.005 0.08 0.01. Element. Ni. Cr. Mo. % Composition .... parameters on the porosity content in Al(Mg)-Al2O3 cast particulate ...




    Full Text Available Friction stir welding is one of the recent solid state joining processes that has drawn the attention of the metal joining community. In this work the effects of tool rotation speed (TRS and welding speed (WS on the tensile strength of dissimilar friction stir welded AA2024-AA7075 joints are investigated. Response surface methodology is used for developing a mathematical model for the tensile strength of the dissimilar aluminum alloy joints. The model is used to investigate the effect of TRS and WS on the tensile strength of the joints. It is seen that the tensile strength of the joint increases with the increase in TRS up to a limit of 1050 rpm and decreases thereafter. The tensile strength of the joints is also seen increasing with the WS up to 15 mm/min. Further increase in WS results in a reduction of the tensile strength of the joints.

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

    Craig C. Menzemer


    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.

  19. Interface strength and degradation of adhesively bonded porous aluminum oxides

    T. Abrahami, Shoshan; M. M. de Kok, John; Gudla, Visweswara Chakravarthy


    environmental and health regulations. Replacing this traditional process in a high-demandingand high-risk industry such as aircraft construction requires an in-depth understanding of the underlying adhesion and degradationmechanisms at the oxide/resin interface resulting from alternative processes......, a minimum pore size is pivotal for the formation of a stableinterface, as reflected by the initial peel strengths. Second, the increased surface roughness of the oxide/resin interface caused byextended chemical dissolution at higher temperature and higher phosphoric acid concentration is crucial to assure...... bond durabilityunder water ingress. There is, however, an upper limit to the beneficial amount of anodic dissolution above which bonds are pronefor corrosive degradation. Morphology is, however, not the only prerequisite for good bonding and bond performance alsodepends on the oxides’ chemical...

  20. Dynamic yield and tensile strength of aluminum single crystals at temperatures up to the melting point

    Kanel, G. I.; Razorenov, S. V.; Baumung, K.; Singer, J.


    This article presents experimental results of the dynamic yield strength and dynamic tensile strength ({open_quotes}spall strength{close_quotes}) of aluminum single crystals at shock-wave loading as a function of temperature. The load duration was {similar_to}40 and {similar_to}200 ns. The temperature varied from 20 to 650{degree}C which is only by 10{degree}C below the melting temperature. A linear growth of the dynamic yield strength by more than a factor of 4 was observed within this temperature range. This is attributed to the phonon drag effect on the dislocation motion. High dynamic tensile strength was maintained over the whole temperature range, including the conditions at which melting should start in a material under tension. This could be an indication of the existence of superheated states in solid crystals. {copyright} 2001 American Institute of Physics.

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

    Chang Sun


    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.

  2. Creep properties and microstructure of the new wrought austenitic steel

    Vlasak, T.; Hakl, J.; Novak, P. [SVUM a.s., Prague (Czech Republic); Vyrostkova, A. [Slovak Academy of Sciences, Kosice (Slovakia). Inst. of Materials Research


    The contribution is oriented on the new wrought austenitic steel BGA4 (Cr23Ni15Mn6Cu3W1.5NbVMo) developed by the British Corus Company. Our main aim is to present creep properties studied in SVUM a.s. Prague during COST 536 programme. The dependencies of the creep strength, strength for specific creep strain and minimum creep strain rate were evaluated on the basis of long term creep tests carried out at temperature interval (625; 725) C. Important part of a paper is metallographic analysis. (orig.)


    Hua Chen


    Full Text Available Cellulosic paper is thermolabile and its strength properties tend to decrease under high temperature conditions. In this work, the effects of aluminum trihydrate filler on the tensile and burst strength of paper prepared from bleached wood pulps were investigated. The use of aluminum trihydrate maintained the tensile and burst strength of paper sheet dried at 200 °C for 4 hours. Thermogravimetric analysis and differential scanning calorimetry gave the evidence that the maintainance of strength after drying associated with the use of aluminum trihydrate filler is possibly due to the increase in degradation temperature and heat absorption of cellulosic paper. The results regarding Fourier Transform Infrared spectroscopy, and the water retention value (WRV and crystallinity index of fibers indicated the alleviated degradation of fibers when aluminum trihydrate was incorporated into the paper matrix.

  4. Precipitation behavior of aluminum alloy 2139 fabricated using additive manufacturing

    Brice, Craig, E-mail: [NASA Langley Research Center, Hampton, VA 23681 (United States); Shenoy, Ravi [Northrop Grumman Corporation Technical Services, Hampton, VA 23681 (United States); Kral, Milo; Buchannan, Karl [University of Canterbury, Christchurch (New Zealand)


    Additive manufacturing (AM) is an emerging technology capable of producing near net shape structures in a variety of materials directly from a computer model. Standard metallic alloys that were developed for cast or wrought processing have largely been adopted for AM feedstock. In many applications, these legacy alloys are quite acceptable. In the aluminum alloy family, however, there is a significant performance gap between the casting alloys currently being used in AM processes and the high strength/toughness capability available in certain wrought alloys. The precipitation hardenable alloys, most often used in high performance structures, present challenges for processing by AM. The near net shape nature of AM processes does not allow for mechanical work prior to the heat treatment that is often necessary to develop a uniform distribution of precipitates and give peak mechanical performance. This paper examines the aluminum (Al) alloy 2139, a composition that is strengthened by homogeneous precipitation of Ω (Al{sub 2}Cu) plates and thus ideally suited for near net shape processes like AM. Transmission electron microscopy, microhardness, and tensile testing determined that, with proper processing conditions, Al 2139 can be additively manufactured and subsequently heat treated to strength levels comparable to those of peak aged wrought Al 2139.

  5. Understanding pH and ionic strength effects on aluminum sulfate-induced microalgae flocculation.

    Cui, Y; Yuan, W; Cheng, J


    The objective of this study was to understand the effect of pH and ionic strength of aluminum sulfate on the flocculation of microalgae. It was found that changing pH and ionic strength influenced algal flocculation by changing the zeta potential of cells, which was described by the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO). For both algal species of Scenedesmus dimorphus and Nannochloropsis oculata, cells with lower total DLVO interaction energy had higher flocculation efficiency, indicating that the DLVO model was qualitatively accurate in predicting the flocculation of the two algae. However, the two algae responded differently to changing pH and ionic strength. The flocculation of N. oculata increased with increasing aluminum sulfate concentration and favored either low (pH 5) or high (pH 10) pH where cells had relatively low negative surface charges. For S. dimorphus, the highest flocculation was achieved at low ionic strength (1 μM) or moderate pH (pH 7.5) where cell surface charges were fully neutralized (zero zeta potential).

  6. Correlation between microstructural features and tensile strength for friction welded joints of AA-7005 aluminum alloy

    Seyyed Mostafa Tahsini; Ayyub Halvaee; Hamed Khosravi


    Similar friction welded joints of AA-7005 aluminum rods were fabricated using different combinations of process parameters such as friction pressure (1.0, 1.5 and 2.0 MPa) and friction time (10, 15 and 20 s). Interfacial microstructure and formation of intermetallic compounds at the joint interface were evaluated via scanning electron microscopy (SEM) equipped with energy dispersive spectrum (EDS), and optical microscopy (OM). Microstructural observations reveal the formation of intermetallic phases during the welding process which cannot be extruded from the interface. Theses phases influence the tensile strength of the resultant joints. From the tensile characteristics viewpoint, the greatest tensile strength value of 365 MPa is obtained at 1.5 MPa and 15 s. Finally, the role of microstructural features on tensile strength of resultant joints is discussed.

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

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


    obtained with unreinforced 356 aluminum casting. Good strength can be obtained with a sound die casting without any defects produced by squeeze casting. The use of higher pressure to produce the squeeze casting has been shown to increase the strength of a hemispherical dome casting. This dome shape casting has been produced both with and without reinforcement and tested to determine its pressure resistance under internal pressure of water. Only a slight improvement in strength could be determined because of water leaks at the seal between hemispherical dome and its flat supporting side. However, when the ability of the casting was tested under the compressive force of a plunger, the strengthening effect of wire mesh or sheet was evident. Higher loads to failure were obtained because of the reinforcement of the stainless steel wire and punched sheet. Rather than a sudden failure occurring, the reinforcement of the stainless steel wire or the punched hard stainless steel sheet held the material together and prevented any loss of the fractured casting to the surroundings. Unalloyed steel did not have the required strength or mechanical properties to increase the properties of the casting.

  8. Tensile strength on friction stir processed AMg5 (5083) aluminum alloy

    Chumaevsky, A. V.; Eliseev, A. A.; Filippov, A. V.; Rubtsov, V. E.; Tarasov, S. Yu.


    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.

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

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


    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.

  10. Comparison of joint designs for laser welding of cast metal plates and wrought wires.

    Takayama, Yasuko; Nomoto, Rie; Nakajima, Hiroyuki; Ohkubo, Chikahiro


    The purpose of the present study was to compare joint designs for the laser welding of cast metal plates and wrought wire, and to evaluate the welded area internally using X-ray micro-focus computerized tomography (micro-CT). Cast metal plates (Ti, Co-Cr) and wrought wires (Ti, Co-Cr) were welded using similar metals. The specimens were welded using four joint designs in which the wrought wires and the parent metals were welded directly (two designs) or the wrought wires were welded to the groove of the parent metal from one or both sides (n = 5). The porosity and gap in the welded area were evaluated by micro-CT, and the maximum tensile load of the welded specimens was measured with a universal testing machine. An element analysis was conducted using an electron probe X-ray microanalyzer. The statistical analysis of the results was performed using Bonferroni's multiple comparisons (α = 0.05). The results included that all the specimens fractured at the wrought wire when subjected to tensile testing, although there were specimens that exhibited gaps due to the joint design. The wrought wires were affected by laser irradiation and observed to melt together and onto the filler metal. Both Mo and Sn elements found in the wrought wire were detected in the filler metal of the Ti specimens, and Ni was detected in the filler metal of the Co-Cr specimens. The four joint designs simulating the designs used clinically were confirmed to have adequate joint strength provided by laser welding.

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

    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.

  12. Investigation of Material Performance Degradation for High-Strength Aluminum Alloy Using Acoustic Emission Method

    Yibo Ai


    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.

  13. Evaluation of mechanical properties of a low-cobalt wrought superalloy

    Dreshfield, R. L.


    In the late 1970s and early 1980s, cobalt was subjected to significant supply and market pressures. Those pressures caused renewed attention to the use of cobalt in aircraft engines. A NASA-sponsored program called Conservation of Strategic Aerospace Materials (COSAM) was created in response to the supply problems with cobalt and other aerospace metals. Among the work performed in the COSAM program and simultaneously by others were several studies on laboratory-size heats of wrought nickel-base super-alloys. These studies suggested that the cobalt levels of the alloys might be reduced by about half, with minimal negative impact on mechanical properties. The Lewis Research Center procured a 1365-kg (3000-lb) heat of a modified Waspaloy having a reduced cobalt level. This article reports the results of a program performed at four gas turbine manufacturers which evaluated the mechanical properties of forgings fabricated from that heat. The alloy chemistry selected reduced the nominal cobalt level from 13.5 to 7.75 wt%. To compensate for the anticipated strength reduction caused by a slight reduction in the amount of γ, the nominal aluminum was increased from 1.3 to 1.5% and the titanium was increased from 3.0 to 3.2%. The increase in aluminum and titanium were intended to increase the amount of γ in the al-loy. Tensile, creep-rupture, low-cycle fatigue, and cyclic crack growth tests were performed. In addition the effect of hydrogen on the alloy was determined. It was concluded that, in the event of a cobalt short-age, a low-cobalt modification of Waspaloy alloy could be substituted for Waspaloy with little develop-ment in those applications that are not creep-rupture limited. With some additional development to better control the grain size, it is probable that most of the current Waspaloy requirements might be met with a lower cobalt alloy.

  14. Dynamic Crystallization: An Influence on Degree of Prior Deformation and Mechanical Strength of 6063 Aluminum Alloy

    Gbenebor, O.P


    Full Text Available This research is aimed at investigating the influence dynamic solidification of melts on degree of mechanical deformation and mechanical strength of 6063 aluminum alloy. Cylindrical samples of 14mm diameter and 140mm long were die cast following two techniques – vibration and static. Prior deformation via forging was imposed on each solidified sample to achieve 7%, 14%, 21% and 28% thickness reductions respectively for each casting technique. Average deformation load, average hammer velocities and the average energy absorbed were recorded. Tensile properties of each sample were studied via the use of Monsanto tensometer. Mechanical agitation of mould and its content increased the machinability of the alloy even at higer pre deformation. This was justified by the failure of the 28% reduction sample cast on static floor during machining to a tensile piece. The energy absorbed during deformation influences the tensile strength of the material. This increases with increase in percentage deformation except for 28% reduction whose magnitude was lower than that subjected to 21% reduction; vibrated samples possessed superior properties. From results obtained, vibrating a sample and subjecting to 21% pre-deformation possessed the best tensile strength.

  15. Effect of aluminum anodizing in phosphoric acid electrolyte on adhesion strength and thermal performance

    Lee, Sulki; Kim, Donghyun; Kim, Yonghwan; Jung, Uoochang; Chung, Wonsub


    This study examined the adhesive bond strength and thermal performance of the anodized aluminum 6061 in phosphoric acid electrolyte to improve the adhesive bond strength and thermal performance for use in metal core printed circuit boards (MCPCB). The electrolyte temperature and applied voltage were altered to generate varied pore structures. The thickness, porosity and pore diameter of the anodized layer were measured. The pore morphologies were affected most by temperature, which was the driving force for ion transportation. The mechanism of adhesive bond was penetration of the epoxy into the pores. The optimal anodization conditions for maximum adhesive bond strength, 27 MPa, were 293 K and 100V. The maximum thermal conductivity of the epoxy-treated anodized layer was 1.6 W/m·K at 273 K. Compared with the epoxy-treated Al layer used for conventional MCPCBs, the epoxy-treated anodized layer showed advanced thermal performance due to a low difference of thermal resistance and high heat dissipation.

  16. Super High Strength Aluminum Alloy Processed by Mechanical Alloying and Hot Extrusion

    Zheng, Ruixiao; Yang, Han; Wang, Zengjie; Wen, Shizhen; Liu, Tong; Ma, Chaoli

    Nanostructure strengthened aluminum alloy was prepared by powder metallurgic technology. The rapid solidification Al-Cu-Mg alloy powder was used in this study. To obtain nanostructure, the commercial powder was intensely milled under certain ball milling conditions. The milled powder was compacted first by cold isostatic pressing (CIP) at a compressive pressure of 300MPa, and then extruded at selected temperature for several times to obtain near full density material. Microstructure and mechanical properties of the extruded alloy were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and mechanical tests. It is revealed that the compressive strength of extruded alloy is higher than 800MPa. The strengthening mechanism associated with the nanostructure is discussed.

  17. New development in welding thin-shell aluminum alloy structures with high strength

    徐文立; 范成磊; 方洪渊; 田锡唐


    From the viewpoint of welding mechanics, two new welding methods-welding with trailing peening and welding with trailing impactive rolling were introduced. For aluminum alloy thin-shell structures with high strength, welding will lead to hot cracking, poor joint and distortion. In order to solve them, trailing impactive device was used behind welding torch to impact the different positions of welded joints, thus realizing the welding with free-hot cracking, low distortion and joint strengthening. By use of impactive rolling wheels instead of peening heads, the outlook of welded specimen can be improved and stress concentration at weld toes can be reduced. Equipment of this technology is simple and portable. It can used to weld sheets, longitudinal and ring-like beams of tube-like structures, as well as the thin-shell structures with closed welds such as flanges and hatches. So the technology has the wide application foreground in the fields of aviation and aerospace.


    XU Lianghong; TIAN Zhiling; ZHANG Xiaomu; PENG Yun


    20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded. The effects of the compositions of filier wires, the heat input and the compositions of shielding gas on the mechanical properties and microstructure of the welded joint have been investigated. The results indicate that finer microstructure, better mechanical properties and higher value of hardness of HAZ can be obtained by using lower heat input. The use of Ar/He mixed shielding gas has several advantages over pure Ar shielding gas. With the increase of the proportion of He in the mixed shielding gas, the grain size of the weld metal as well as porosity susceptibility decreases. When the volume ratio of He to Ar reaches 7:3, the porosity and the grain size of weld metal reach the minimum, and the porosity can be further reduced by filling some CO2.

  19. Experimental and Numerical Study on the Strength of Aluminum Extrusion Welding

    Sedat Bingöl


    Full Text Available The quality of extrusion welding in the extruded hollow shapes is influenced significantly by the pressure and effective stress under which the material is being joined inside the welding chamber. However, extrusion welding was not accounted for in the past by the developers of finite element software packages. In this study, the strength of hollow extrusion profile with seam weld produced at different ram speeds was investigated experimentally and numerically. The experiments were performed on an extruded hollow aluminum profile which was suitable to obtain the tensile tests specimens from its seam weld’s region at both parallel to extrusion direction and perpendicular to extrusion direction. A new numerical modeling approach, which was recently proposed in literature, was used for numerical analyses of the study. The simulation results performed at different ram speeds were compared with the experimental results, and a good agreement was obtained.

  20. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y. [Chungbuk National University, Cheongju (Korea, Republic of)


    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets.

  1. Towards the problem of forming full strength welded joints on aluminum alloy sheets. Part II: AA7475

    Kalashnikova, Tatiana; Tarasov, Sergey; Eliseev, Alexander; Fortuna, Anastasiya


    The microstructural evolution in welded joint zones obtained both by friction stir welding and ultrasonic- assisted friction stir welding on dispersion hardened 7475 aluminum alloy has been examined together with the analysis of mechanical strength and microhardness. It was established that ultrasonic-assisted friction stir provided leveled microhardness profiles across the weld zones as well as higher joint strength as compared to those of standard friction stir welding.

  2. Cold cracking in DC-cast high strength aluminum alloy ingots: An intrinsic problem intensified by casting process parameters

    Lalpoor, M.; Eskin, D.G.; Ruvalcaba, D.; Fjaer, H.G.; Ten Cate, A.; Ontijt, N.; Katgerman, L.


    For almost half a century the catastrophic failure of direct chill (DC) cast high strength aluminum alloys has been challenging the production of sound ingots. To overcome this problem, a criterion is required that can assist the researchers in predicting the critical conditions which facilitate the

  3. A novel aluminum based nanocomposite with high strength and good ductility

    Ramezanalizadeh, Hossein, E-mail: [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Emamy, Masoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Shokouhimehr, Mohammadreza [School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul (Korea, Republic of)


    Aluminum based nanocomposite containing nano-sized Al{sub 3}Mg{sub 2} reinforcing was fabricated via mechanical milling followed by hot extrusion techniques. For this, Al and Al{sub 3}Mg{sub 2} powders were mixed mechanically and milled at different times (0, 2, 5, 7, 10, 15 and 20 h) to achieve Al–10 wt.% Al{sub 3}Mg{sub 2} composite powders. Hot extrusion of cold pressed powders was done at 400 °C with extrusion ratio of 6:1. Microstructures of the powders and consolidated materials were studied using transmission electron microscopy, scanning electron microscope and X-ray diffraction. Fracture surfaces were also investigated by scanning electron microscopy equipped with EDS analyzer. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. In addition, the fabricated composites exhibited homogeneous distribution and less agglomerations of the n-Al{sub 3}Mg{sub 2} with increasing milling time. The mechanical behavior of these nanocomposites was investigated by hardness and tensile tests, which revealed it has four times the strength of a conventional Al along with good ductility. It was found that the ultimate tensile strength (UTS) and elongation of the nanocomposites were significantly improved with increases in milling time up to 15 h. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-Al{sub 3}Mg{sub 2}. Fracture surfaces showed that the interfacial bonding between Al and Al{sub 3}Mg{sub 2} could be improved with increasing in milling time. Also HRTEM results from interface showed that a metallurgical clean interface and intimate contact between matrix and second phase. By extending the milling process up to 20 h, there was no significant improvement in mechanical behavior of materials, due to the completion of milling process and dynamic and static recovery of composite at higher milling times. - Highlights: • A novel aluminum

  4. Light weight and high strength materials made of recycled steel and aluminum

    Nounezi, Thomas

    Recycling has proven not only to address today's economical, environmental and social issues, but also to be imperative for the sustainability of human technology. The current thesis has investigated the feasibility of a new philosophy for Recycling (Alloying-Recycling) using steel 1020 and aluminum 6061T6. The study was limited to the metallurgical aspects only and has highlighted the potential of recycled alloys made of recycled aluminum and steel to exhibit substantially increased wear resistance and strength-to-weight ratio as compared to initial primary materials. Three alloy-mixtures are considered: TN3 (5wt% 1020 +95wt% 6061T6); TN5 (0.7wt% 1020 + 99.3wt% 6061T6); and TN4 (10wt% 6061T6 + 90wt% 1020). A Tucker induction power supply system (3kW; 135-400 kHz) is used to melt the alloy mixtures for casting in graphite crucibles. Heat treatment of the cast samples is done using a radiation box furnace. Microscopy, Vickers hardness and pin-on-disc abrasive wear tests are performed. Casting destroyed the initial microstructures of the alloys leading to a hardness reduction in the as-cast and solution heat-treated aluminum rich samples to 60 Hv from 140 Hv. Ageing slightly increased the hardness of the cast samples and provided a wear resistance two times higher than that of the initial 6061T6 material. On the steel rich side, the hardness of the as-cast TN4 was 480 Hv, which is more than twice as high as the initial hardness of steel 1020 of 202 Hv; this hints to strong internal and residual stress, probably martensite formation during fast cooling following casting. Solution heat treatment lowered the hardness to the original value of steel 1020, but provided about ten (10) times higher wear resistance; this suggests higher ductility and toughness of normalised TN4 as compared to 1020. In addition, TN4 exhibits about 25% weight reduction as compared to 1020. The actual recycling process and the effect of non-metallic impurities shall be investigated in future

  5. Development of Wrought Superalloy in China

    DU Jinhui


    Full Text Available Wrought superalloy development in China was reviewed in recent ten years. The achievement of basic research and development of industrial manufacture technologies were systematically described from the aspects of new alloys, new technologies of hot deformation. New alloys include: new disc materials 718Plus, GH4720Li and GH4065 alloy, combustion chamber alloy GH3230, and GH4706 alloy for gas turbine engines. New technologies include: ERS-CDS new technology of easy segregation materials, multi upsetting-drawing for improving the microstructure uniformity of bars, slow cooling and multi-cycle thermomechanical treatment for increasing hot plasticity of hard-to-work alloys. Finally, the further development of wrought superalloys was prospected.

  6. Development of Wrought Superalloy in China

    DU Jinhui; ZHAO Guangpu; Deng, Qun; LÜ Xudong; ZHANG Beijiang


    Wrought superalloy development in China was reviewed in recent ten years. The achievement of basic research and development of industrial manufacture technologies were systematically described from the aspects of new alloys, new technologies of hot deformation. New alloys include: new disc materials 718Plus, GH4720Li and GH4065 alloy, combustion chamber alloy GH3230, and GH4706 alloy for gas turbine engines. New technologies include: ERS-CDS new technology of easy segregation materials, multi...

  7. Analysis of porosity characteristics in weld metal of high strength aluminum alloy and the effect of mixed shielding gas

    Xiaomu Zhang; Zhiyong Zhang; Yun Peng; Zhiling Tian; Changhong He; Hongjun Xiao; Chengyong Ma [Central Iron and Steel Research Inst., Beijing, BJ (China)


    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.)

  8. Grain size effect on yield strength of titanium alloy implanted with aluminum ions

    Popova, Natalya, E-mail: [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: [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: [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Kalashnikov, Mark, E-mail: [Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Kurzina, Irina, E-mail: [National Research Tomsk State University, 36, Lenin Str., 634050, Tomsk (Russian Federation)


    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.

  9. Non-contact sheet forming using lasers applied to a high strength aluminum alloy

    Rafael Humberto Mota Siqueira


    Full Text Available Laser beam forming (LBF is a contactless mechanical process accomplished by the introduction of thermal stresses on the surface of a material using a laser in order to induce plastic deformation. In this work, LBF was performed on 1.6 mm thick sheets of a high strength aluminum alloy, AA6013-T4 class by using a defocused continuous Yb-fiber laser beam of 0.6 mm in diameter on the sheet top surface. The laser power and process speed were varied from 200 W to 2000 W and from 3 to 30 mm/s, respectively. For these experimental conditions, the bending angle of the sheet ranged from 0.1° to 2.5° per run. In the highest bending angle condition, 1000 W and 30 mm/s, the depth of remelted pool was 0.6 mm and the microstructure near the plate bottom surface remained unaltered. For the whole set of experimental conditions, the hardness remained constant at approximately 100 HV, which is similar to the base material. In order to verify the applicability of the method, some previously T-welded sheets were straightened. The method was efficient in correcting the distortion of the sheets with a bending angle up to 5°.

  10. Effect of welding current and voltage on the mechanical properties of wrought (6063 aluminium alloy

    Oladele Isiaka Oluwole


    Full Text Available This work was carried out to investigate the effect of welded joints on the mechanical properties of wrought (6063 aluminium alloy. The study revealed the influence of current and voltage on the welded joint as well as the mechanical properties of the alloy. The alloy samples were welded together by metal inert gas welding process at varying values of current and voltage after which mechanical tests were performed on the welded samples. The microstructural examination of the various fusion zones obtained was carried out. Appreciable variations in the properties of the welded samples were observed due to changes in the microstructural features of the alloys. It was concluded that variation of current and voltage remarkably affect the mechanical properties of the wrought 6063 Aluminium alloy. As the voltage increases from 25 to 30 V, the ultimate tensile strengths and hardness values increases while the impact strengths decreases but the current did not show such trend.

  11. Identifying Combination of Friction Stir Welding Parameters to Maximize Strength of Lap Joints of AA2014-T6 Aluminum Alloy

    Rajendrana C.


    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°.

  12. Inhibition of Ce3+ on Stress Corrosion Crack of High Strength Aluminum Alloy

    LI Wen-ting


    Full Text Available The stress corrosion cracking (SCC susceptibility of 7A04 high strength aluminum alloy in 3.5% (mass fraction NaCl solution and the Ce3+ inhibition of SCC were investigated by slow stress rate test(SSRT, using constant current polarization, electrochemical noise (ECN and electrochemical impedance spectroscopy (EIS techniques. The inhibition mechanism of Ce3+ ions on the initiation and propagation of cracking was also analyzed. The results indicate that both anodic and cathodic galvanostatic polarizations can accelerate the SCC of 7A04, the former increases anodic dissolution but the latter accelerates hydrogen embrittlement of crack tip. SCC susceptibility of 7A04 can be reduced effectively by the addition of cerium ions, the fracture time is delayed and slowed down, but only during the initiation other than the propagation stage of cracking. Ce3+ ions can restrain the initiation of metastable pitting on the surface of 7A04 specimen, which therefore increase the induction time of the cracking since that the micro pits are usually the source of cracking.However, once the crack begins to propagate or the specimen is notched, the addition of cerium ions can rarely inhibit the cracking process. This is possibly attributed to that the radius of Ce3+ ion is too large to diffuse into the crack tip or it is hard to form protective CeO2 layer, Ce3+ ion therefore fails to rehabilitate the active alloy at the crack tip and further reduce the SCC developing rate of 7A04. SEM also indicates that the crack initiation of smooth 7A04 specimens is mainly induced by metastable or stable pits.

  13. A new method for welding aluminum alloy LY12CZ sheet with high strength


    From the viewpoint of welding mechanics, a new welding technology-trailing peening was applied firstly to weld aluminum alloy LY12CZ sheet with high susceptibility to hot cracking. Trailing peening can exert a transverse extrusion strain on the metal in brittle temperature region (BTR) which can compensate for the tensioning strain during the cooling procedure post welding. So, welding hot cracking of LY12CZ sheet can be controlled effectively on the special jig for hot cracking experiment, and the phenomenon of hot cracking can't be found in specimens with large dimensions finally. At the same time, welding with trailing peening can decrease welding distortion caused by longitudinal and transverse shrinkage of weld obviously. Due to strengthening the poor position-weld toe during the process of welding, the residual stress distribution of welded joint is more reasonable. Contrast with conventional welding, mechanical properties such as tensile strength, prolongation ratio and cold-bending angle of welded joint with trailing peening can be improved obviously, and rupture position of welded joint transits from weld toe at conventional welding to weld metal at trailing peening. So, welding with trailing peening can be regarded as a dynamic welding method with low stress, little distortion and hot cracking-free really. As far as theoretical analysis is concerned, the technology of trailing peening can be used to weld the materials with high susceptibility to hot cracking such as LY12CZ and LD10, and solve the welding distortion of thin plate-shell welded structures which contain closed welds such as flange. In addition, the technology of trailing peening has many advantages: simple device, high efficiency, low cost and flexible application which make the welding method have widely applied foreground in the field of aeronautics and aerospace.

  14. Tensile and elastic properties of deformed heterogeneous aluminum alloys at room and elevated temperatures

    Eskin, D.G. (A.A. Baikov Institute of Metallurgy, Russian Academy of Sciences, 49, Leninskii prosp., Moscow 117334 (Russian Federation)); Toropova, L.S. (A.A. Baikov Institute of Metallurgy, Russian Academy of Sciences, 49, Leninskii prosp., Moscow 117334 (Russian Federation))


    In this study we investigated the tensile and elastic properties of deformed binary Al-Ni, Al-Fe, and Al-Cu alloys containing 10-25 vol.% of second phase. Sheets and rods of the alloys exhibit an increase in Young''s modulus of 15%-25%, and tensile properties at room and elevated temperatures comparable with those of conventional medium-strength wrought aluminum alloys. The elastic moduli of the phases were estimated. ((orig.)). Letter-to-the-editor

  15. Effect of aluminum oxide addition on the flexural strength and thermal diffusivity of heat-polymerized acrylic resin.

    Ellakwa, Ayman E; Morsy, Mohamed A; El-Sheikh, Ali M


    This work was undertaken to investigate the effect of adding from 5% to 20% by weight aluminum oxide powder on the flexural strength and thermal diffusivity of heat-polymerized acrylic resin. Seventy-five specimens of heat-polymerized acrylic resin were fabricated. The specimens were divided into five groups (n = 15) coded A to E. Group A was the control group (i.e., unmodified acrylic resin specimens). The specimens of the remaining four groups were reinforced with aluminum oxide (Al2O3) powder to achieve loadings of 5%, 10%, 15%, and 20% by weight. Specimens were stored in distilled water at 37 degrees C for 1 week before flexural strength testing to failure (5 mm/min crosshead speed) in a universal testing machine. Results were analyzed by one-way analysis of variance and post hoc Tukey paired group comparison tests (p denture bases to provide increased flexural strength and thermal diffusivity. Increasing the flexural strength and heat transfer characteristics of the acrylic resin base material could lead to more patient satisfaction.

  16. Low temperature impact testing of welded structural wrought iron

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  17. Reinforcement of Aluminum Oxide Filler on the Flexural Strength of Different Types of Denture Base Resins: An In vitro Study.

    Dhole, Rohit I; Srivatsa, G; Shetty, Rohit; Huddar, Dayanand; Sankeshwari, Banashree; Chopade, Swapnil


    Acrylic resins have been used extensively for the fabrication of denture bases because of their aesthetic qualities, ease of manipulation and repairability. Flexural fatigue of the denture base has been shown to be a factor in the clinical failure of polymethyl methacrylate resin dentures. Also, the fracture can result from impact, fatigue or degradation of the base material. Hence, there is a need to increase the strength of denture base resins. To evaluate the effect of reinforcing alumina oxide filler on the flexural strength of different acrylic resins. A total of 180 acrylic specimens were fabricated, which were divided into three groups self cure acrylic resin (SC), conventional heat cure resin (HC) and high strength heat cure resin (HI). Each group was divided into four subgroups i.e., control group and the specimens of the remaining three groups were reinforced with aluminum oxide (Al2O3) powder by 5%, 10% and 15% by weight. Specimens were stored in distilled water for one week; flexural strength was tested by universal testing machine. Results were analysed by one-way analysis of variance and post-hoc Tukey paired group comparison tests. Flexural strength of SC increased by 9%, 13% and 19%, Flexural strength of HC increased by 8%, 15% and 19% and that of HI increased by 21%, 26% and 29% compared to control group by adding 5%,10% and 15% of alumina filler (p-value lead to more clinical success.

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

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


    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 ...

  19. Ultrasonic Additive Manufacturing: Weld Optimization for Aluminum 6061, Development of Scarf Joints for Aluminum Sheet Metal, and Joining of High Strength Metals

    Wolcott, Paul J.

    Ultrasonic additive manufacturing (UAM) is a low temperature, solid-state manufacturing process that enables the creation of layered, solid metal structures with designed anisotropies and embedded materials. As a low temperature process, UAM enables the creation of active composites containing smart materials, components with embedded sensors, thermal management devices, and many others. The focus of this work is on the improvement and characterization of UAM aluminum structures, advancing the capabilities of ultrasonic joining into sheet geometries, and examination of dissimilar material joints using the technology. Optimized process parameters for Al 6061 were identified via a design of experiments study indicating a weld amplitude of 32.8 synum and a weld speed of 200 in/min as optimal. Weld force and temperature were not significant within the levels studied. A methodology of creating large scale builds is proposed, including a prescribed random stacking sequence and overlap of 0.0035 in. (0.0889 mm) for foils to minimize voids and maximize mechanical strength. Utilization of heat treatments is shown to significantly increase mechanical properties of UAM builds, within 90% of bulk material. The applied loads during the UAM process were investigated to determine the stress fields and plastic deformation induced during the process. Modeling of the contact mechanics via Hertzian contact equations shows that significant stress is applied via sonotrode contact in the process. Contact modeling using finite element analysis (FEA), including plasticity, indicates that 5000 N normal loads result in plastic deformation in bulk aluminum foil, while at 3000 N no plastic deformation occurs. FEA studies on the applied loads during the process, specifically a 3000 N normal force and 2000 N shear force, show that high stresses and plastic deformation occur at the edges of a welded foil, and base of the UAM build. Microstructural investigations of heat treated foils confirms

  20. Microstructural features of intergranular brittle fracture and cold cracking in high strength aluminum alloys

    Lalpoor, M.; Eskin, D. G.; ten Brink, Gert; Katgerman, L.


    Intergranular brittle fracture has been mainly observed and reported in steel alloys and precipitation hardened At-alloys where intergranular precipitates cover a major fraction of the grain boundary area. 7xxx series aluminum alloys suffer from this problem in the as-cast condition when brittle

  1. A study on the strength of an armour-grade aluminum under high strain-rate loading

    Appleby-Thomas, G. J.; Hazell, P. J.


    The aluminum alloy 5083 in tempers such as H32 and H131 is an established light-weight armour material. While its dynamic response under high strain-rates has been investigated elsewhere, little account of the effect of material orientation has been made. In addition, little information on its strength under such loadings is available in the literature. Here, both the longitudinal and lateral components of stress have been measured using embedded manganin stress gauges during plate-impact experiments on samples with the rolling direction aligned both orthogonal and parallel to the impact axis. The Hugoniot elastic limit, spall, and shear strengths were investigated for incident pressures in the range 1-8 GPa, providing an insight into the response of this alloy under shock loading. Further, the time dependence of lateral stress behind the shock front was investigated to give an indication of material response.



    Diffusion couples of tool materials (prepared from commercially available high speed steel and YW1 carbide tools) and the wear-resisting aluminum bronze (KK) were prepared by casting to study the diffusion pattern and phase formation sequence in order to clarify the diffusion wear of the tools during the turning of the wear-resisting aluminum bronze. Optical micrographs show that good contact was obtained at the tool material-KK interface. After annealed at 900 ℃ for 6 h, strong inter-diffusion across the interface was observed. Microprobe analysis was used to study the elemental distribution across the interface and X-ray diffractometry was used to study the phases formed at the interface.

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


    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

  4. Push-out bond strength of oval versus circular fiber posts irradiated by erbium-doped yttrium aluminum garnet laser.

    Uzun, Ismail; Keskin, Cangül; Özsu, Damla; Güler, Buğra; Aydemir, Hikmet


    Fiber posts in conjunction with resin cements are widely used to provide retention in endodontically treated teeth. The bond strength of restorative materials to root canal dentin is an important issue for the long-term success of restorative procedures. The push-out test is widely used to measure the bonding between the post and radicular dentin. The purpose of this in vitro study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er-YAG) laser treatment of dentinal walls on the bond strength of circular and oval fiber posts luted in oval root canals. Forty mandibular premolar teeth were endodontically treated and restored with 2 different intracanal post systems. Push-out tests were performed and data were analyzed by using 2-way analysis of variance and post hoc Bonferroni tests. Laser pretreatment of dentinal walls resulted in higher push-out bond strength than that of the nonlasered groups (Pfiber posts showed significantly higher push-out bond strength values than those of circular fiber posts in the coronal region (P.05). The laser pretreatment with an oval ultrasonic tip of an oval fiber post system improved bonding to root canal dentin when compared with a circular post system with conventional preparation. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.


    W.D.Cao; R.L.Kennedy


    Research and development efforts are still very active on 718-type alloys although two major members of this widely used family, 718 and 625, were invented almost a half-century ago.Emphasis in this type of work at ATI Allvac is directed at improving existing alloys and developing new alloys to meet ever-increasing industrial demands.The improvement of existing alloys is exemplified by addition of minor elements P and B in alloy 718.The discovery of the beneficial effect of P and B in wrought alloy 718 led to development of a new, modified alloy, AllvacR 718ERR.A large effort has also been directed at studying the effects of major element modifications in 718-type alloys, and a new alloy, AllvacR 718PlusTM, has been developed.The new alloy has much better high temperature capability, especially thermal stability, approaching the level of Waspaloy but retains excellent processing characteristics, similar to alloy 718.Alloy 718PlusTM should be useful in any 718-type application requiring a higher working temperature.The properties and processing of this alloy are introduced in this paper.

  6. Study on the Optimum Cutting Parameters of an Aluminum Mold for Effective Bonding Strength of a PDMS Microfluidic Device

    Caffiyar Mohamed Yousuff


    Full Text Available Master mold fabricated using micro milling is an easy way to develop the polydimethylsiloxane (PDMS based microfluidic device. Achieving high-quality micro-milled surface is important for excellent bonding strength between PDMS and glass slide. The aim of our experiment is to study the optimal cutting parameters for micro milling an aluminum mold insert for the production of a fine resolution microstructure with the minimum surface roughness using conventional computer numerical control (CNC machine systems; we also aim to measure the bonding strength of PDMS with different surface roughnesses. Response surface methodology was employed to optimize the cutting parameters in order to obtain high surface smoothness. The cutting parameters were demonstrated with the following combinations: 20,000 rpm spindle speed, 50 mm/min feed rate, depth of cut 5 µm with tool size 200 µm or less; this gives a fine resolution microstructure with the minimum surface roughness and strong bonding strength between PDMS–PDMS and PDMS–glass.

  7. Influence of ceramic particulate type on microstructure and tensile strength of aluminum matrix composites produced using friction stir processing

    I. Dinaharan


    Full Text Available Friction stir processing (FSP was applied to produce aluminum matrix composites (AMCs. Aluminum alloy AA6082 was used as the matrix material. Various ceramic particles, such as SiC, Al2O3, TiC, B4C and WC, were used as reinforcement particle. AA6082 AMCs were produced using a set of optimized process parameters. The microstructure was studied using optical microscopy, filed emission scanning electron microscopy and electron back scattered diagram. The results indicated that the type of ceramic particle did not considerably vary the microstructure and ultimate tensile strength (UTS. Each type of ceramic particle provided a homogeneous dispersion in the stir zone irrespective of the location and good interfacial bonding. Nevertheless, AA6082/TiC AMC exhibited superior hardness and wear resistance compared to other AMCs produced in this work under the same set of experimental conditions. The strengthening mechanisms and the variation in the properties are correlated to the observed microstructure. The details of fracture mode are further presented.

  8. Assessment of wrought ASTM F1058 cobalt alloy properties for permanent surgical implants.

    Clerc, C O; Jedwab, M R; Mayer, D W; Thompson, P J; Stinson, J S


    The behavior of the ASTM F1058 wrought cobalt-chromium-nickel-molybdenum-iron alloy (commonly referred to as Elgiloy or Phynox) is evaluated in terms of mechanical properties, magnetic resonance imaging, corrosion resistance, and biocompatibility. The data found in the literature, the experimental corrosion and biocompatibility results presented in this article, and its long track record as an implant material demonstrate that the cobalt superalloy is an appropriate material for permanent surgical implants that require high yield strength and fatigue resistance combined with high elastic modulus, and that it can be safely imaged with magnetic resonance.

  9. Optimization of Squeeze Casting Parameters for 2017 A Wrought Al Alloy Using Taguchi Method

    Najib Souissi


    Full Text Available This study applies the Taguchi method to investigate the relationship between the ultimate tensile strength, hardness and process variables in a squeeze casting 2017 A wrought aluminium alloy. The effects of various casting parameters including squeeze pressure, melt temperature and die temperature were studied. Therefore, the objectives of the Taguchi method for the squeeze casting process are to establish the optimal combination of process parameters and to reduce the variation in quality between only a few experiments. The experimental results show that the squeeze pressure significantly affects the microstructure and the mechanical properties of 2017 A Al alloy.

  10. Process of friction-stir welding high-strength aluminum alloy and mechanical properties of joint

    王大勇; 冯吉才; 郭德伦; 孙成彬; 栾国红; 郭和平


    The process of friction-stir welding 2A12CZ alloy has been studied. And strength and elongation tests have been performed, which demonstrated that the opportunity existed to manipulate friction-stir welding parameters in order to improve a range of material properties. The results showed that the joint strength and elongation arrived at their parameters changing, joint tensile strength and elongation had similar development. Hardness measurement indicated that the weld was softened. However, there was considerable difference in softening degree for different joint zone. The weld top had lower hardness and wider softening zone than other zone of the weld. And softening zone at advancing side was wider than that at retreating side.

  11. Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

    ZHUO Long-Chao; PANG Shu-Jie; WANG Hui; ZHANG Tao


    Based on a new approach for designing glassy alloy compositions,bulk Al-based alloys with good glass-forming ability (GFA) are synthesized.The cast Al86Si0.5Ni4.06Co2.94 Y6Sc0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod.The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 Gpa and maximum strength of 1.27 Gpa as well as an obvious plastic strain of about 2.4% during compressive deformation.This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability.

  12. High-Strength Aluminum Casting Alloy for High-Temperature Applications (MSFC Center Director's Discretionary Fund Final Project No. 97-10)

    Lee, J. A.


    A new aluminum-silicon alloy has been successfully developed at Marshall Space Flight Center that has a significant improvement in tensile strength at elevated temperatures (550 to 700 F). For instance, the new alloy shows in average tensile strength of at least 90 percent higher than the current 390 aluminum piston alloy tested at 500 F. Compared to conventional aluminum alloys, automotive engines using the new piston alloy will have improved gas mileage, and may produce less air pollution in order to meet the future U.S. automotive legislative requirements for low hydrocarbon emissions. The projected cost for this alloy is less than $0.95/lb, and it readily allows the automotive components to be cast at a high production volume with a low, fully accounted cost. It is economically produced by pouring molten metal directly into conventional permanent steel molds or die casting.

  13. Application of a criterion for cold cracking to casting high strength aluminum alloys

    Lalpoor, M.; Eskin, D.G.; Fjaer, H.G.; Ten Cate, A.; Ontijt, N.; Katgerman, L.


    Direct chill (DC) casting of high strength 7xxx series aluminium alloys is difficult mainly due to solidification cracking (hot cracks) and solid state cracking (cold cracks). Poor thermal properties along with extreme brittleness in the as-cast condition make DC-casting of such alloys a challenging

  14. Strength distribution at interface of rotary-friction-welded aluminum to nodular cast iron

    SONG Yu-lai; LIU Yao-hui; ZHU Xian-yong; YU Si-rong; ZHANG Ying-bo


    The morphology, size and composition of intermetallic compound at the interface of Al 1050 and nodular cast iron were studied by electron microprobe analysis(EMPA) and scan electron microscopy (SEM), respectively. The bond strength of the interface was measured by the tensile tests and the morphology of the fracture surface was observed by SEM. The observation of the interface reveals that there are two distinct morphologies: no intermetallic compound exists in the central area at the interface; while numbers of intermetallic compounds (FexAly) are formed in the peripheral area due to the overfull heat input. The tensile tests indicate that the distribution of strength in radial direction at the interface is inhomogeneous, and the central area of the interface performs greater bond strength than the peripheral area, which proves directly that the FexAly intermetallic compounds have a negative effect on the integration of interface. The morphology on the fracture surface shows that the facture in the central area at the interface has characteristic of the ductile micro-void facture. So it is important to restrain the form of the intermetallic compound to increase the bond strength of the Al 1050 and nodular cast iron by optimizing welding parameters and the geometry of components.

  15. Optimizing friction stir welding parameters to maximize tensile strength of AA2219 aluminum alloy joints

    Babu, S.; Elangovan, K.; Balasubramanian, V.; Balasubramanian, M.


    AA2219 aluminium alloy (Al-Cu-Mn alloy) has gathered wide acceptance in the fabrication of lightweight structures requiring a high strength-to-weight ratio and good corrosion resistance. In contrast to the fusion welding processes that are routinely used for joining structural aluminium alloys, the friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force etc., and the tool pin profile play a major role in determining the joint strength. An attempt has been made here to develop a mathematical model to predict the tensile strength of friction stir welded AA2219 aluminium alloy by incorporating FSW process parameters. A central composite design with four factors and five levels has been used to minimize the number of experimental conditions. The response surface method (RSM) has been used to develop the model. The developed mathematical model has been optimized using the Hooke and Jeeves search technique to maximize the tensile strength of the friction stir welded AA2219 aluminium alloy joints.

  16. Application of a criterion for cold cracking to casting high strength aluminum alloys

    Lalpoor, M.; Eskin, D.G.; Fjaer, H.G.; Ten Cate, A.; Ontijt, N.; Katgerman, L.


    Direct chill (DC) casting of high strength 7xxx series aluminium alloys is difficult mainly due to solidification cracking (hot cracks) and solid state cracking (cold cracks). Poor thermal properties along with extreme brittleness in the as-cast condition make DC-casting of such alloys a challenging

  17. Effect of the Cold-Sprayed Aluminum Coating-Substrate Interface Morphology on Bond Strength for Aircraft Repair Application

    Blochet, Quentin; Delloro, Francesco; N'Guyen, Franck; Jeulin, Dominique; Borit, François; Jeandin, Michel


    This article is dealing with the effects of surface preparation of the substrate on aluminum cold-sprayed coating bond strength. Different sets of AA2024-T3 specimens have been coated with pure Al 1050 feedstock powder, using a conventional cold spray coating technique. The sets were grit-blasted (GB) before coating. The study focuses on substrate surface topography evolution before coating and coating-substrate interface morphology after coating. To study coating adhesion by LASAT® technique for each set, specimens with and without preceding GB treatment were tested in load-controlled conditions. Then, several techniques were used to evaluate the effects of substrate surface treatment on the final coating mechanical properties. Irregularities induced by the GB treatment modify significantly the interface morphology. Results showed that particle anchoring was improved dramatically by the presence of craters. The substrate surface was characterized by numerous anchors. Numerical simulation results exhibited the increasing deformation of particle onto the grit-blasted surface. In addition, results showed a strong relationship between the coating-substrate bond strength on the deposited material and surface preparation.

  18. Corrosion Properties of Sintered and Wrought Stainless Seel

    Mathiesen, Troels; Maahn, Ernst Emanuel


    The corrosion properties of a range of stainless steels produced by powder metallurgy (PM) are compared with wrought AISI304 and AISI316 Steel. Characterisation of the passivation properties in 0.5M H2SO4 and pittingresistance in 0.3% chloride solution by polarisation show properties of the sinte......The corrosion properties of a range of stainless steels produced by powder metallurgy (PM) are compared with wrought AISI304 and AISI316 Steel. Characterisation of the passivation properties in 0.5M H2SO4 and pittingresistance in 0.3% chloride solution by polarisation show properties...

  19. Precipitation of aluminum nitride in a high strength maraging steel with low nitrogen content

    Jeanmaire, G., E-mail: [Institut Jean Lamour, UMR 7198 CNRS-Université de Lorraine, 54011 Nancy Cedex (France); Aubert and Duval, BP1, 63770 Les Ancizes (France); Dehmas, M.; Redjaïmia, A. [Institut Jean Lamour, UMR 7198 CNRS-Université de Lorraine, 54011 Nancy Cedex (France); Puech, S. [Aubert and Duval, BP1, 63770 Les Ancizes (France); Fribourg, G. [Snecma Gennevilliers, 171 Boulevard de Valmy-BP 31, 92702 Colombes (France)


    In the present work, aluminum nitride (AlN) precipitation was investigated in a X23NiCoCrMoAl13-6-3 maraging steel with low nitrogen content (wt.% N = 5.5 ppm). A reliable and robust automatic method by scanning electron microscopy observations coupled with energy dispersive X-ray spectroscopy was developed for the quantification of AlN precipitates. The first stage was to identify the solvus temperature and to develop a heat treatment able to dissolve the AlN precipitates. The experimental determination of equilibrium conditions and solvus temperature show good agreement with ThermoCalc® simulation. Then, from this AlN-free state, the cooling rate, isothermal holding time and temperature were the subject of an intensive investigation in the austenite region of this maraging steel. In spite of the high temperatures used during heat treatments, the growth kinetic of the largest AlN precipitates (> 1 μm) is slow. The cooling rate has a major effect on the size and the number density of AlN due to a higher driving force for nucleation at low temperatures. At last, quenching prior to isothermal annealing at high temperatures leads to fine and dense AlN precipitation, resulting from the martensite to austenite transformation. Experimental results will be discussed and compared with kinetic data obtained with the mobility database MobFe2 implemented in Dictra® software. - Highlights: • Slow dissolution kinetic of AlN precipitates due to both their large size and small chemical driving force • Significant effects of cooling rate prior isothermal heat treatment, holding time and temperature on AlN precipitation • Size of AlN precipitates can be reduced by quenching prior isothermal holding. • Fine precipitation of AlN related to the α → γ transformation.

  20. Microstructure and strength of a deformation processed aluminum-20%tin metal-metal composite

    Xu, Kai

    An Al-20vol.% Sn metal-metal composite was deformation processed by extrusion, swaging, and wire drawing to a total true strain of 7.4, resulting in a microstructure with Sn filaments in an Al matrix. Both the size and spacing of the Sn filaments decreased as deformation processing progressed. Immediately after deformation, the Sn second phase showed a convoluted, ribbon-shaped filamentary morphology, but the Sn filaments spheroidized during prolonged storage at room temperature. The driving force for spheroidization is chemical potential gradient due to curvature difference along Sn filaments. A critical wavelength of lambda crit = 2piR can be used to determine the spheroidization tendency of Sn cylinder. When lambda > 2piR, spheroidization is predicted to occur. The strength of these composites increased exponentially with the reduction in spacing of the Sn filaments. The relationship between UTS and deformation true strain is UTS = 72.6 exp(0.20eta). A Hall-Petch relationship between strength and filament spacing has been observed. Strengthening results from the filaments acting as barriers for dislocation motion. The primary shape instability modes are cylinderization of ribbons, boundary splitting, spheroidization of cylinders, and edge spheroidization of ribbons. The determining factors dictating which mechanism is active are grain boundary energy, interfacial energy, and ribbon cross section aspect ratio. The fiber texture was determined by orientation imaging microscopy to be for Al and for Sn. The 290 MPa ultimate tensile strength of the composite was greater than the rule-of-mixtures prediction. Comparisons are made with Al-Nb, Al-Ti and Al-Mg deformation processed metal metal composites and to various strengthening models for metal-metal composites.

  1. Microstructures and constituents of super-high strength aluminum alloy ingots made through LFEC process

    WANG Shuang


    Full Text Available Ingots of a new super-high strength Al-Zn-Mg-Cu-Zr alloy were produced respectively by low frequency electromagnetic casting (LFEC and by conventional direct chill (DC casting process. Microstructure and constituents of the ingots were studied. The results indicated that the LFEC process significantly refines microstructure and constituents of the alloy, and to some extent, decreases the area (or volume fraction of constituents and eutectic structure precipitated at grain boundaries. But, no difference in the type of constituents was observed between LFEC and DC ingots. The results also showed LFEC process can improve the as-cast mechanical properties.

  2. Effect of cyclic high loading rates on the fatigue strength of aluminum-based composites

    Calderon Arteaga, Hermes Eskander

    The study of fatigue under high loading rates is of great interest in the complete characterization of a new series of composites with Al-Cu-Mg matrix reinforced with AlB2 dispersoids. Homogeneous and functionally graded composites were prepared via gravity and centrifugal casting, respectively. Through centrifugal casting a gradual variation of the volume fraction of reinforcing particles along the cross section was obtained. In specific fabrication conditions, even complete segregation of the reinforcement particles was achieved. Charpy impact tests as well as hardness tests were conducted to assess the composite strength as a function of the weight percent of boron. The tensile properties of gravity cast samples were obtained. Then for both casting conditions, simple edge-notched bend SE(B) specimens were tested under fatigue conditions (three-point bending). The results from impact and hardness tests allowed identifying an interaction between the Mg dissolved in the matrix and the diborides. This interaction, which has never been reported before, was responsible for the strength reduction observed. It was assumed that a substitutional diffusion of Al by Mg atoms in the hp3 structure of diboride was causing the strength reduction, and three approaches were developed to estimate the amount of Mg depleted from the matrix by the diborides during the composite processing. Gravity cast samples were more sensitive to monotonic damage due to fatigue loads where compared with functionally-graded composites. Contrary to the centrifugal cast samples, gravity samples were also affected by the loading rate. The Mg-AlB2 interaction was also responsible for the reduction in the fatigue resistance as the weight percent of boron increased in both types of composites; regression models were obtained to predict the crack growth curve slope change as function of the boron level. The particle distribution showed to affect the crack growth behavior of the FGMs, decreasing the

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

    Lee, Jonathan A.; Chen, Po Shou


    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 thermal growth stability, surface hardness and wear resistant properties.

  4. Predictions of precipitation reaction mechanisms for 7xxx series aluminum alloys cast by CDS technique

    Sobrino, Luca

    The need to reduce the fleet fuel consumption is pushing the automotive industry to reduce vehicles weight. In this context high strength aluminum alloys are a viable alternative to the heavier steel currently adopted. In particular 7xxx series wrought alloys, thanks to their excellent strength to weight ratio, are drawing the attention of carmakers. The development of the Controlled Diffusion Solidification (CDS) technique allows now the casting of these alloys into near net shapes, thus reducing all the costs related to the manufacturing process and making them attractive. Because of the completely different microstructure resulting from the CDS process, a new design of the heat treatments is required to achieve the best mechanical properties. This project therefore evaluates the macro and microhardness evolution of CDS cast 7xxx alloys in T4 and T6 conditions to predict their precipitation sequence, thus providing useful information for the heat treatments design.

  5. An investigation of the microstructures and properties of metal inert gas and friction stir welds in aluminum alloy 5083

    A R Yazdipour; A Shafiei M; H Jamshidi Aval


    Two different types of welds, Metal Inert Gas (MIG) and Friction Stir Welding (FSW), have been used to weld aluminum alloy 5083. The microstructure of the welds, including the nugget zone and heat affected zone, has been compared in these two methods using optical microscopy. The mechanical properties of the weld have been also investigated using the hardness and tensile tests. The results show that both the methods could successfully be used to weld such alloy. The strength of the joints is comparable to the strength of the base metal in both cases. However, FSWed samples have shown higher strength in comparison to the MIG samples. The results also show that the extension of the heat affected zone is higher in the MIG method in comparison to the FSW method. The weld metal microstructure of MIG welded specimen contains equiaxed dendrites as a result of solidification process during MIG welding while FSWed samples have wrought microstructures.

  6. Influence of Temperature on Mechanical Behavior During Static Restore Processes of Al-Zn-Mg-Cu High Strength Aluminum Alloy

    ZHANG Kun


    Full Text Available Flow stress behaviors of as-cast Al-Zn-Mg-Cu high strength aluminum alloy during static restore processes were investigated by: Isothermal double-pass compression tests at temperatures of 300-400℃, strain rates of 0.01-1 s-1, strains of 33% +20% with the holding times of 0~900 s after the first pass compression. The results indicate that the deformation temperature has a dramatical effect on mechanical behaviors during static restore processes of the alloy. (1 At 300 ℃ and 330 ℃ lower temperatures, the recovery during the deformation is slow, and deformation energy stored in matrix is higher, flow stresses at the second pass deformation decreased during the recovery and recrystallization, and the stress softening phenomena is observed. Stress softening is increased with the increasing holding time; Precipitation during the holding time inhibites the stress softening. (2 At 360 ℃ and 400 ℃ higher temperatures, the recovery during deformation is rapid, and deformation energy stored in matrix is lower. Solid solubility is higher after holding, so that flow stress at the second pass deformation is increased, stress hardening phenomena is observed. Stress hardening decreased with the increasing holding time duo to the recovery and recrystallization during holding period at 360 ℃; Precipitation during holding also inhibited the stress softening. However, Stress hardening remains constant with the increasing holding time duo to the reasanenal there are no recovery and recrystallization during holding period at 400 ℃.

  7. Evolution of undissolved phases in high-zinc content super-high strength aluminum alloy during ageing

    张坤; 刘志义; 叶呈武; 许晓嫦; 郑青春


    The evolution of undissolved phases in the high-zinc content super-high strength aluminum alloy during ageing was investigated by means of SEM and EIS. The results show that undissolved phases of Cu-rich M(AlZnMgCu) exist in the silver-free alloy at solid-solution state. With increasing the ageing time, the precipitation of agehardening precipitates MgZn2 stimulates Zn atoms within the undissolved phases to diffuse into the matrix, and thus the Cu content in the M(AlZnMgCu) phase increases relatively. For the silver-bearing alloy, small addition of Ag promotes the formation of Ag-rich M(A1ZnMgCuAg) undissolved phases and deteriorates mechanical properties of the alloy. At the early stage of ageing, Ag content within the M(AlZnMgCuAg) phases greatly decreases due to rapid diffusing of Ag atoms into the matrix and the co-clustering of Ag and Mg atoms. As the ageing time prolonging, the precipitation of MgZn2 results in the decrease of Zn content in the undissolved phases, and the relative increase of Ag and Mg contents.

  8. Flow Behavior and Microstructural Evolution of 7A85 High-Strength Aluminum Alloy During Hot Deformation

    Liu, Xingang; Han, Shuang; Chen, Lei; Yang, Shuai; Jin, Miao; Guo, Baofeng; Mao, Tianhong


    Hot deformation behavior of 7A85 high-strength aluminum alloy was investigated at 593 K to 713 K (320 °C to 440 °C) and 0.01-10 s-1. The manifestation of flow curves was related to the strain rate. Typical single-peak curves were shown below 10 s-1, while two stress peaks appeared in the case of 10 s-1 and the second peak strain was almost three times larger than the first one. A constitutive equation considering the effect of strain was developed. Flow stress values predicted by the constitutive model demonstrated a good agreement with the experimental results over the entire range of strain rates and temperatures. Microstructure characterization revealed that dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) which depended on the Zener-Hollomon parameter (Z) closely, co-occurred at large strain (ɛ = 0.7). With decreasing Z-value, the dominant dynamic restoration mechanism gradually transformed from DRV to CDRX. The average subgrain size (d sub) showed a power-law relationship with Z. Recrystallization was sensitively dependent on the strain rate at above 683 K (410 °C). The fine equiaxed grains appeared at original grain boundaries and in deformed grains interior owing to CDRX. The high-curvature subgrain boundaries can also cause the nucleation of recrystallization within deformed grains.

  9. Effect of Prestraining of Recrystallization Temperature and Mechanical Properties of Commercial, Sintered, Wrought Molybdenum

    Dike, Kenneth C; Long, Roger A


    Given three presumably identical lots of commercial, sintered, wrought molybdenum, the 1-hour recrystallization temperature of one lot remained above 2900 F by limiting the amount of effective restraining to 35 percent or less. Different recrystallization temperatures were obtained in various atmospheres, the highest in argon and the lowest in hydrogen. Metal thus fabricated and then stress-relieved possessed an ultimate tensile strength at room temperature within 10 percent of metal swaged 99 percent and also possessed equivalent ductility. At 1800 F, equivalent strength and ductility was obtained irrespective of the amount of swaging over the range of 10 to 99 percent. The amount of swaging greatly influenced the recrystallized grain size but the difference in grain size is not the major controlling factor which determines whether recrystallized molybdenum is ductile or brittle at room temperature.

  10. Low-aluminum content iron-aluminum alloys

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


    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. Microstructure and mechanical properties of wrought magnesium alloy AZ31B welded by laser-TIG hybrid

    刘黎明; 宋刚; 王继锋; 梁国俐


    The laser-TIG hybrid welding was mainly used to weld the wrought magnesium alloy AZ31B. The technical characteristics of laser-TIG hybrid welding process was investigated and the interactional mechanism between laser and arc was discussed, at the same time the microstructure and mechanical properties of the wrought magnesium alloy AZ31B using laser-TIG hybrid welding were analyzed by optical microscope, EPMA, SEM, tensile machine, hardness machine. The experimental results show that the presence of laser beam boosts up the stability of the arc during high speed welding and augments the penetration of weld; the crystal grains of magnesium alloy weld are fine without porosity and cracks in the best welding criterion and the microstructure of HAZ does not become coarse obviously. The elements profile analysis reveals that Mg content in the weld is lower than that of the base metal, but Al content is higher slightly. Under this experimental condition, the wrought magnesium alloy AZ31B joint can be achieved using laser-TIG hybrid process and the tensile strength of the joint is equivalent to that of the base metal.

  12. Art of Wrought Copper in Turkey

    Nuran KAYABAŞI


    Full Text Available Among the handicraft, art of being a coppersmith has been occurred intensively in the past. The fast developing socio - economic structure diminished the value and the place of the copper vessels. Heavy and beautiful vessels made by beating left their places to thin, light aluminum, pl astic, glass and steel vessels made by machinery. The demand for copper is diminished. Therefore being a coppersmith has become less and less important every day. However, in the last few years, copper vessels becoming a touristic souvenir became a source of hope for the traditional coppersmith art to live on. Copperworking is applied in our country in some regions and there are people who live off it. Souvenirs, daily used vessels, and requirements of the rural areas are produced in centers such as İstanb ul, Ankara, Tokat, Çorum, Erzincan, Diyarbakır, Kahramanmaraş, Gaziantep, Bursa, Kastamonu, Çankırı, Giresun and Trabzon. The situation of being a coppersmith in Turkey is explained, examples are given from souvenir copper items produced in Ankara, and sug gestions are made to keep this craft alive.

  13. Modeling and sensitivity analysis on the transport of aluminum oxide nanoparticles in saturated sand: effects of ionic strength, flow rate, and nanoparticle concentration.

    Rahman, Tanzina; Millwater, Harry; Shipley, Heather J


    Aluminum oxide nanoparticles have been widely used in various consumer products and there are growing concerns regarding their exposure in the environment. This study deals with the modeling, sensitivity analysis and uncertainty quantification of one-dimensional transport of nano-sized (~82 nm) aluminum oxide particles in saturated sand. The transport of aluminum oxide nanoparticles was modeled using a two-kinetic-site model with a blocking function. The modeling was done at different ionic strengths, flow rates, and nanoparticle concentrations. The two sites representing fast and slow attachments along with a blocking term yielded good agreement with the experimental results from the column studies of aluminum oxide nanoparticles. The same model was used to simulate breakthrough curves under different conditions using experimental data and calculated 95% confidence bounds of the generated breakthroughs. The sensitivity analysis results showed that slow attachment was the most sensitive parameter for high influent concentrations (e.g. 150 mg/L Al2O3) and the maximum solid phase retention capacity (related to blocking function) was the most sensitive parameter for low concentrations (e.g. 50 mg/L Al2O3).

  14. A Tri-modal 2024 Al -B4C composites with super-high strength and ductility: Effect of coarse-grained aluminum fraction on mechanical behavior

    Alireza Abdollahi


    Full Text Available In this study, ultrafine grained 2024 Al alloy based B4C particles reinforced composite was produced by mechanical milling and hot extrusion. Mechanical milling was used to synthesize the nanostructured Al2024 in attrition mill under argon atmosphere up to 50h. A similar process was used to produce Al2024-5%wt. B4C composite powder. To produce trimodal composites, milled powders were combined with coarse grained aluminum in 30 and 50 wt% and then were exposed to hot extrusion at 570°C. The microstructure of hot extruded samples were studied by optical microscope, Transmission electron microscope (TEM and scanning electron microscope (SEM equipped with EDS spectroscopy. The mechanical properties of samples were compared by using tensile, compression and hardness tests. The results showed that the strength, after 50 h milling and addition of 5wt% B4C, increased from 340 to 582 MPa and the hardness increased from 87 HBN to 173 HBN, but the elongation decreased from 14 to 0.5%. By adding the coarse-grained aluminum powder, the strength and hardness decreased slightly, but the increases in return. Ductility increase is the result of increase in dislocation movements and strength increase is the result of restriction in plastic deformation by nanostructured regions. Furthermore, the strength and hardness of trimodal composites were higher, but their ductility was lower.

  15. 7000系高强铝合金的发展及其在飞机上的应用%Development and Application of 7000 High Strength Aluminum Alloys on Airplane



    This paper presented a comprehensive review on research development in 7000 high strength aluminum alloy. The application of plane aluminum alloys was enumerated. Several existing problems in present home-made high strength aluminum alloys were pointed out, and the suggestions in the selection of high strength aluminum alloy for principal parts of airplane were presented.%阐述了7000系高强度铝合金的国内外发展现状,列举了高强度铝合金在国外飞机上的应用情况,指出了目前国内飞机用高强铝合金材料存在的问题,并对高强铝合金在未来飞机机体的选用提出了建议,供设计人员参考使用。

  16. Effects of carbon and hafnium concentrations in wrought powder-metallurgy superalloys based on NASA 2B-11 alloy

    Miner, R. V., Jr.


    A candidate alloy for advanced-temperature turbine engine disks, and four modifications of that alloy with various C and Hf concentrations were produced as cross-rolled disks from prealloyed powder that was hot isostatically compacted. The mechanical properties, microstructures, and phase relations of the alloys are discussed in terms of their C and Hf concentrations. A low-C and high-Hf modification of IIB-11 had the best balance of mechanical properties for service below about 750 C. Because of their finer grain sizes, none of the powder-metallurgy alloys produced had the high-temperature rupture strength of conventionally cast and wrought IIB-11.

  17. Effect of low-frequency electromagnetic field on the as-cast microstructure of a new super high strength aluminum alloy by horizontal continuous casting


    The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-cast microstructure was studied. Results show that microstructure of the sample prepared by the LFEHC process was greatly refined. Microstructures at the border and the center of the ingots were fine, uniform and rosette-shaped.Electromagnetic frequency plays a key role in microstructure refining. Fine and uniform microstructures can be obtained with optimal electromagnetic frequency. In this experiment, under a frequency of 30 Hz the microstructure was the finest and the most uniform.

  18. Sharply notch cylindrical tension specimen for screening plane-strain fracture toughness. I - Influence of fundamental testing variables on notch strength. II Applications in aluminum alloy quality assurance of fracture toughness

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.; Bucci, R. J.; Collis, S. F.; Kohm, R. F.; Kaufman, J. G.


    A description is presented of studies which have been conducted to establish an improved technology base for a use of the sharply notched cylindrical specimen in quality assurance tests of aluminum alloy products. The results are presented of an investigation of fundamental variables associated with specimen preparation and testing, taking into account the influence of the notch root radius, the eccentricity of loading, the specimen diameter, and the notch depth on the sharp notch strength. Attention is given to the statistical procedures which are necessary to establish correlations between the sharp notch strength and the plane-strain fracture toughness for high-strength aluminum alloys.

  19. Application of wrought leadcalcium batteries in Europe

    Achtermann, M. D.; Greenlee, M. E.

    Use of leadcalcium batteries in automotive applications offers definite advantages in the areas of overcharge, high temperature, water usage, and self-discharge. The Delco Freedom battery with wrought expanded grids additionally provides increased resistance to corrosion. Customer satisfaction with the sealed, maintenance-free battery has been well established in the field. Still to be recognized are some aspects of static testing in the laboratory. This technology is now poised for the future by offering battery location flexibility in the vehicle and meeting the no maintenance expectations of the customer.

  20. Aluminum alloy

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


    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.

  1. Influence of multi-step heat treatments in creep age forming of 7075 aluminum alloy: Optimization for springback, strength and exfoliation corrosion

    Arabi Jeshvaghani, R.; Zohdi, H. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Shahverdi, H.R., E-mail: [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Bozorg, M. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Hadavi, S.M.M. [School of Materials Science and Engineering, MA University of Technology, P.O. Box 16765-3197, Tehran (Iran, Islamic Republic of)


    Multi-step heat treatments comprise of high temperature forming (150 Degree-Sign C/24 h plus 190 Degree-Sign C for several minutes) and subsequent low temperature forming (120 Degree-Sign C for 24 h) is developed in creep age forming of 7075 aluminum alloy to decrease springback and exfoliation corrosion susceptibility without reduction in tensile properties. The results show that the multi-step heat treatment gives the low springback and the best combination of exfoliation corrosion resistance and tensile strength. The lower springback is attributed to the dislocation recovery and more stress relaxation at higher temperature. Transmission electron microscopy observations show that corrosion resistance is improved due to the enlargement in the size and the inter-particle distance of the grain boundaries precipitates. Furthermore, the achievement of the high strength is related to the uniform distribution of ultrafine {eta} Prime precipitates within grains. - Highlights: Black-Right-Pointing-Pointer Creep age forming developed for manufacturing of aircraft wing panels by aluminum alloy. Black-Right-Pointing-Pointer A good combination of properties with minimal springback is required in this component. Black-Right-Pointing-Pointer This requirement can be improved through the appropriate heat treatments. Black-Right-Pointing-Pointer Multi-step cycles developed in creep age forming of AA7075 for improving of springback and properties. Black-Right-Pointing-Pointer Results indicate simultaneous enhancing the properties and shape accuracy (lower springback).

  2. Bearing Casting Technology of High-strength Aluminum Alloy ZL205A%高强度铝合金ZL205A支座铸造技术

    崔恩强; 王宝兵; 肖旅


      Smelting process and heat treatment of high-strength aluminum alloy ZL205A were investigated. According to the characteristics and quality of the support structure requirements, the practical casting process was developed and a bearing casting was poured. The results show that the performance and quality of the high-strength aluminum alloy ZL205A castings meet to the design requirements and it has basically the same reliability with forgings used in bearings, which can be a substitute to reduce the manufacturing cost of the structural parts and shorten the manufacturing cycle.%  对高强度铝合金ZL205A的熔炼工艺、热处理工艺进行了研究,并根据支座的结构特点和质量要求,制定了切实可行的铸造工艺方案,浇注了支座铸件。结果表明,ZL205A高强度铝合金铸件性能和质量满足设计指标要求,且可靠性与锻件基本相同,从而可代替锻件应用于支座,降低结构件制造成本,缩短制造周期。

  3. 49 CFR 230.26 - Tensile strength of shell plates.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tensile strength of shell plates. 230.26 Section... Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of steel or wrought-iron shell plates is not known, it shall be taken at 50,000 psi for steel and...

  4. Standard test method for exfoliation corrosion susceptibility in 2XXX and 7XXX Series Aluminum Alloys (EXCO Test)

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers a procedure for constant immersion exfoliation corrosion (EXCO) testing of high-strength 2XXX and 7XXX series aluminum alloys. Note 1—This test method was originally developed for research and development purposes; however, it is referenced, in specific material specifications, as applicable for evaluating production material (refer to Section 14 on Precision and Bias). 1.2 This test method applies to all wrought products such as sheet, plate, extrusions, and forgings produced from conventional ingot metallurgy process. 1.3 This test method can be used with any form of specimen or part that can be immersed in the test solution. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Microstructure characteristics and mechanical property of aluminum alloy/stainless steel lap joints fabricated by MIG welding-brazing process

    Zhang Hongtao, E-mail: [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Liu Jiakun [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China)


    Highlights: {yields} Wrought aluminum and stainless steel was joined with welding-brazing process. {yields} Effect of different layers on spreadability of molten filler metal was examined. {yields} Mechanical property of the joints with different heat inputs was investigated. {yields} Microstructure of the joints were also studied by OM, SEM and TEM. {yields} Phase composition was ascertained by diffraction spot and XRD analysis. - Abstract: Lap joints of aluminum alloy 2B50 and stainless steel 1Cr18Ni9Ti were welded by MIG welding-brazing method with 4043 Al-Si filler metal. The effect of aluminizing coating and galvanized zinc coating on fusion metal spreadability were studied. The aluminized coating had limited effect to promote weld surface appearance and obvious micro-cracks were found between the compound layer and the steel side. The fracture in tensile tests occurred at the interfacial layer of the weld with a low tensile strength about 60 MPa. Joints between aluminum alloy and galvanized steel had good surface appearances and the intermetallic compound in fusion zone region close to joint interface was Al{sub 4.5}FeSi. The thickness of the intermetallic compound layer varied from about 5 {mu}m to 15 {mu}m depending on the heat input and the highest tensile strength of lap joint could reached 193.6 MPa when the heat input is 0.846 KJ/cm.

  6. The Mechanical Properties of ALCA PlusTM Cast Aluminum Amplifier Top Plates

    Biltoft, P; Gourdin, W H; Sanchez, R J; Shen, T H


    The amplifier top plates are monolithic, cast aluminum structures from which the amplifier frame assembly units (FAUs), and the line-replaceable flash lamp units (LRUs) inside them, are hung on the support rails in the laser bays. When fully assembled, each plate must support a static weight of 10,600 or 16,000 pounds, depending upon whether two or three loaded FAUs are attached. The top plates are fabricated from ''ALCA Plus{trademark}'', a zinc-containing aluminum casting alloy similar in composition to some standard alloys in the 7000-series. For electrical reasons, all of the plate with the exception of the support ''ears'', is encased in epoxy as shown in Figure 1. The nominal chemistry of the aluminum alloy is summarized in Table 1 and the nominal mechanical characteristics are summarized in Table 2. For comparison, wrought alloys of similar composition in the 7000-series have ultimate strengths of approximately 33-76 ksi and elongations of 11-17%, depending upon the temper.

  7. Effect of Neodymium on As-Cast Microstructure and Mechanical Properties of AZ31 Wrought Alloy

    Li Mingzhao; Fan Jinping; Zhang Junyuan; Liu Xuguang; Xu Bingshe


    Nd in the form of powder or intermediate alloy was added to AZ31 wrought alloy. The as-obtained alloy was characterized and tested with respect to its microstructure and mechanical properties. The relationship between the microstructure, mechanical properties and tensile fracture mechanism were discussed, with relevant alloys as reference for comparison. Experimental results show that the same quantity of Nd was added into AZ31 in powder form or in intermediate alloy, the absorption rate of Nd reached only 10.8% for the former case and as high as 95% for the later case. Pure Nd powder was added, no new compound was detected, but it served as reductant and purified alloy melt, resulting in improving the tensile strength while Nd was added into AZ31 as Mg-Nd intermediate alloy. The compound Al2Nd and Mg12 Nd were formed in magnesium alloy, which were distributed in the matrix in the shapes of strip and particle, evidently refined the as-cast structure. The as-cast tensile strength (228MPa) of adding pure Nd powder approximated to the figure (245MPa) of adding Mg-Nd intermediate alloy. The tensile fracture mchanism of as-cast AZ31 transformed from cleavage fracture into quasi-cleavage fracture.

  8. Microstructure and Tensile Properties of Wrought Al Alloy 5052 Produced by Rheo-Squeeze Casting

    Lü, Shulin; Wu, Shusen; Wan, Li; An, Ping


    The semisolid slurry of wrought Al alloy 5052 was prepared by the indirect ultrasonic vibration (IUV) method, in which the horn was vibrated under the outside of the metallic cup containing molten alloy, and then shaped by direct squeeze casting (SC). Spherical primary α-Al particles were uniformly dispersed in the matrix and presented a bimodal distribution of grain sizes. The effects of rheo-squeeze casting (RSC) parameters such as squeeze pressure and solid fraction on the microstructure and tensile properties of the semisolid alloy were investigated. The results indicate that average diameters of the primary α-Al particles decreased with the increase of squeeze pressure, while the tensile properties of the alloy increased. With the increase of solid fraction, the tensile strength increased first and then decreased, but the elongation decreased continuously. The best tensile properties were achieved when the slurry with a solid fraction of 0.17 solidified under 100 MPa. Compared to conventional squeeze casting, RSC process can offer the 5052 alloy better tensile strength and elongation, which were improved by 9.7 pct and 42.4 pct, respectively.

  9. Formation of reacted interfacial zone and improvement of bonding strength in aluminum alloy clad stainless steel and aluminum alloy clad copper plateusing explosive welding technique. Al gokin no stainless ko oyobi do eno bakuhatsu assetsu ni okeru kaimen hannoso no keisei to setsugo kyodo

    Hokamoto, K.; Fujita, M. (Kumamoto University, Kumamoto (Japan). Faculty of Engineering); Izuma, T. (Asahi Chemical Industry Co. Ltd., Tokyo (Japan))


    Explosive welding experiments using intermediate materials have been performed on combinations of aluminum alloy with stainless steel, and aluminum alloy with copper that are difficult of explosive welding with an ordinary method. The experiments have investigated interfacial reaction layers and bonding strength. The drive plates have used four kinds of aluminum alloy plates with a thickness of 4 mm and a base material of stainless steel (SUS 304) or copper having a thickness of 9 mm. Investigation has been given on how the interfacial structure and the bonding strength change as a result of using intermediate materials of the similar kind with the base material. The composition in the generated reaction layers has higher aluminum concentration than that has been predicted. This is because more aluminum component has been dissolved because of transformation having converged on the side of the aluminum alloy with smaller transformation resistance. Use of the intermediate materials can reduce energy of collision given on the interface, thus controlling the formation of reactive layers on the interface. This has improved the bonding strength largely, leading to a possibility of fabricating clad materials that have good interface properties. 10 refs., 9 figs., 3 tabs.

  10. Effects of aluminum oxide addition on the flexural strength, surface hardness, and roughness of heat-polymerized acrylic resin

    Mahroo Vojdani


    Conclusion: Reinforcement of the conventional heat-cured acrylic resin with 2.5 wt% Al2O3 powder significantly increased its flexural strength and hardness with no adverse effects on the surface roughness.

  11. Modifier cation (Ba, Ca, La, Y) field strength effects on aluminum and boron coordination in aluminoborosilicate glasses: the roles of fictive temperature and boron content

    Morin, Elizabeth I. [Stanford University, Department of Chemistry, Stanford, CA (United States); Wu, Jingshi; Stebbins, Jonathan F. [Stanford University, Department of Geological and Environmental Sciences, Stanford, CA (United States)


    The field strength of modifier cations has long been known to have important effects on oxide glass properties, but effects on network structure can be complex. For two series of barium, calcium, lanthanum and yttrium aluminoborosilicates with two different B/Si ratios, we report systematic variations in boron and aluminum coordination determined by NMR, and glass transition and heat capacities from differential scanning calorimetry. Data on glasses with different fictive temperatures allow B and Al speciation to be compared on an isothermal basis, rather than as conventionally done for as-quenched structures. Temperature and compositional effects can thus be isolated. These data and comparison to previous studies on glasses with lower B/Si ratios clearly show that higher modifier cation field strength increases the fraction of five- and six-coordinated Al in all compositions. In contrast, the previously documented trend towards more three-coordinated boron (and hence more non-bridging oxygens, NBO) in low B/Si glasses with higher field strength cations reverses in high B/Si and in high NBO compositions. Al and B coordination numbers both decrease with higher fictive temperature in the glasses studied here, suggesting a simple mechanism of coupled structural change. (orig.)

  12. Exploring the effects of SiC reinforcement incorporation on mechanical properties of friction stir welded 7075 aluminum alloy: Fatigue life, impact energy, tensile strength

    Bahrami, Mohsen, E-mail: [Faculty of Mining and Metallurgical Engineering, Amirkabir University of Technology (AUT), Hafez Avenue, Tehran (Iran, Islamic Republic of); Helmi, Nader [Faculty of Mining and Metallurgical Engineering, Amirkabir University of Technology (AUT), Hafez Avenue, Tehran (Iran, Islamic Republic of); Dehghani, Kamran [Faculty of Mining and Metallurgical Engineering, Amirkabir University of Technology (AUT), Hafez Avenue, Tehran (Iran, Islamic Republic of); Centre of Excellence in Smart Structures and Dynamical Systems (Iran, Islamic Republic of); Givi, Mohammad Kazem Besharati [Department of Mechanical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)


    In the current research, the role of SiC nano-particles in improving the mechanical properties of friction stir welded (FSWed) 7075 aluminum alloy is investigated. To this end, friction stir welding (FSW) was conducted at 1250 rpm and 40 mm/min. The experiment carried out with and without incorporating SiC nano-particles along the joint line. Cross-sectional microstructures of the joints were characterized employing optical and scanning electron microscopy (SEM). Results achieved through X-ray diffraction (XRD) confirmed the presence of SiC powders. Moreover, it was discovered that the volume fraction of the reinforcement particles was 20%. Along with an excellent bonding between SiC nano-particles and aluminum matrix, SEM photograph demonstrated a good dispersion of SiC reinforcements. Atomic force microscopy (AFM) results were also in tight agreement with the recent SEM microstructure. Thanks to the presence of SiC nano-particles, tensile strength, percent elongation, fatigue life, and toughness of the joint improved tremendously. The fracture morphologies were in good agreement with corresponding ductility results.

  13. Structure and strength of aluminum with sub-micrometer/micrometer grain size prepared by spark plasma sintering

    Le, G.M.; Godfrey, A.; Hansen, Niels


    A spark plasma sintering (SPS) technique has been applied to prepare fully dense Al samples from Al powder. By applying a sintering temperature of 600°C and a loading pressure of 50MPa, fully recrystallized samples of nearly 100% density with average grain sizes of 5.2μm, 1.3μm and 0.8μm have been...... the initial powder particle size. The SPS samples show higher strength than Al samples with an identical grain size prepared using thermo-mechanical processing, and a better strength-ductility combination, with the 1.3μm grain size sample showing a yield strength (σ0.2%) of 140MPa and a uniform elongation...

  14. Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139 Aluminum Alloys


    and R.S. Mishra, Effect of Friction Stir 940Processing on the Microstructure of Cast A356 Aluminum , Mater. Sci. 941Eng. A, 2006, 433, p 269–278...REPORT Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139 Aluminum Alloys 14. ABSTRACT 16. combined with the basic physical metallurgy of two wrought aluminum alloys to predict/assess their FSW behaviors. The two alloys selected are AA5083

  15. Development and property evaluation of nuclear grade wrought FeCrAl fuel cladding for light water reactors

    Yamamoto, Y.; Pint, B. A.; Terrani, K. A.; Field, K. G.; Yang, Y.; Snead, L. L.


    Development of nuclear grade, iron-based wrought FeCrAl alloys has been initiated for light water reactor (LWR) fuel cladding to serve as a substitute for zirconium-based alloys with enhanced accident tolerance. Ferritic alloys with sufficient chromium and aluminum additions can exhibit significantly improved oxidation kinetics in high-temperature steam environments when compared to zirconium-based alloys. In the first phase, a set of model FeCrAl alloys containing 10-20Cr, 3-5Al, and 0-0.12Y in weight percent, were prepared by conventional arc-melting and hot-working processes to explore the effect of composition on the properties of FeCrAlY alloys. It was found that the tensile properties were insensitive to the alloy compositions studied; however, the steam oxidation resistance strongly depended on both the chromium and the aluminum contents. The second phase development focused on strengthening Fe-13Cr-5Al with minor alloying additions of molybdenum, niobium, and silicon. Combined with an optimized thermo-mechanical treatment, a thermally stable microstructure was produced with improved tensile properties at temperatures up to 741 °C.

  16. Implants for surgery -- Metallic materials -- Part 3: Wrought titanium 6-aluminium 4-vanadium alloy

    International Organization for Standardization. Geneva


    Specifies the characteristics of, and corresponding test methods for, the wrought titanium alloy known as titanium 6-aluminium 4-vanadium alloy (Ti 6-Al 4-V alloy) for use in the manufacture of surgical implants.

  17. The mechanical response of a uranium-nobium alloy: a comparison of cast versus wrought processing

    Cady, Carl M [Los Alamos National Laboratory; Gray, George T., III [Los Alamos National Laboratory; Cerreta, Ellen K [Los Alamos National Laboratory; Aikin, Robert M [Los Alamos National Laboratory; Chen, Shuh - Rong [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Lopez, Mike F [Los Alamos National Laboratory; Korzekwa, Deniece R [Los Alamos National Laboratory; Kelly, Ann M [Los Alamos National Laboratory


    A rigorous experimentation and validation program is being undertaken to create constitutive models that elucidate the fundamental mechanisms controlling plasticity in uranium-6 wt.% niobium alloys (U-6Nb). The first, 'wrought', material produced by processing a cast ingot I'ia forging and forming into plate was studied. The second material investigated is a direct cast U-6Nb alloy. The purpose of the investigation is to detennine the principal differences, or more importantly, similarities, between the two materials due to processing. It is well known that parameters like grain size, impurity size and chemistry affect the deformation and failure characteristics of materials. Metallography conducted on these materials revealed that the microstructures are quite different. Characterization techniques like tension, compression, and shear were performed to find the principal differences between the materials as a function of stress state. Dynamic characterization using a split Hopkinson pressure bar in conjunction with Taylor impact testing was conducted to derive and thereafter validate constitutive material models. The Mechanical Threshold Strength Model is shown to accurately capture the constitutive response of these materials and Taylor cylinder tests are used to provide a robust way to verify and validate the constitutive model predictions of deformation by comparing finite element simulations with the experimental results. The primary differences between the materials will be described and predictions about material behavior will be made.

  18. Towards the problem of forming full strength welded joints on aluminum alloy sheets. Part I: AA2024

    Fortuna, Sergey; Eliseev, Alexander; Kalashnikova, Tatiana; Kolubaev, Evgeny


    This work shows the microstructural evolution of solid solution grains and secondary phase precipitates in the stirring zones of ultrasonic-assisted friction stir welding (UAFSW) and standard friction stir welding (FSW). As shown, fine spherical AlMgCu precipitates dominate in FSW stirring zone whereas nanosized Al2MgCu (S-phase) platelets ones are the main finding in UAFSW sample. The mechanical strength of AA2024 is provided by precipitation of coherent intermetallic S-phase particles. The dominating amount of S-phase precipitates in UAFSW sample provided the ultimate stress level close to that of the base metal, i.e. 402 MPa as compared to 302 MPa of FSW sample. These values constituted 93 and 85%, respectively, of the base metal strength.

  19. Analysis of Friction Stir Welding of Aluminum Alloys and Optimization of Welding Parameters for Maximum Tensile Strength

    Prof. S. K. Aditya


    Full Text Available The Friction Stir Welding (FSW process is an innovative technique to join metals in the plastic state thus not reaching the liquid state as it happen in traditional welding processes. This feature of the FSW proved that a modification can be done on the fatigue behavior and strength of the welding joints so, some of the leading companies to adopted the process for the manufacturing of Automotive, Locomotive, Shipping & Aerospace. The FSW is a variant of the linear friction welding process in which the material is being welded without bulk melting. The FSW parameters such as tool Rotational speed, Welding speed, Axial Force, Tool tilt angle, Welding Tool Shoulder Diameter, and Welded Plate thickness play a major role in determining the properties like Tensile strength, hardness, residual stress, HAZ etc. of the joints. Our objective is to optimize the welding parameters to achieve Max. Tensile Strength of Aluminium Alloys (especially on AA-2xxx, AA-5xxx under FSW. We only wish to optimize (by Taguchi and ANOVA method with three variable input parameters (Rotational speed in rpm, Translation speed in mm/min & Axial force in KN considering a cylindrical pin.

  20. Study on FSW Process Parameters of High Strength Aluminum Alloy%高强铝合金的搅拌摩擦焊工艺参数研究



    采用搅拌摩擦焊方法对7022铝合金进行了焊接试验.试验结果表明:n/v值的大小体现了搅拌头旋转速度n与焊接速度v的匹配程度,反映了焊接单位长度焊缝所产生的热量多少和搅拌头的搅拌次数,直接反映其焊缝性能的优劣.当n/v=4时,二者的匹配程度最高,焊缝抗拉强度及屈服强度各自为母材的102.5%、99.10%,焊核区微观组织为形状均匀、粒度细小而致密的等轴再结晶晶粒,焊缝性能达到最佳状态;当n/v值在3~5变化时,其焊缝性能良好.%The friction-stir-welding of 7022 high-strength aluminum plate was completed. The experiment results show that the value of the nlv embodies the mixing head rotation speed and welding speed matching degree, which can reflect the welding unit length weld heat generated by the number and mixing head agitation frequency, directly reflect the performance of friction stir weld quality. When n/V=A, the matching degree is highest, the weld tensile strength and yield strength of the matrix metal is respectively 102.5%, 99.10%. The microstructure of welding nuclear zone is uniform shape, particle size in small and compact and shaft recrystallization grain, the weld seam performance can achieve the best condition; when nlv value is in 3-5, the weld seam performance is good.

  1. High-strength bolt-forming of fine-grained aluminum alloy 6061 with a continuous hybrid process

    Kim, Ji Hun; Hwang, Sun Kwang [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Im, Yong-Taek, E-mail: [National Research Laboratory for Computer Aided Materials Processing, Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Son, Il-Heon; Bae, Chul Min [Wire Rod Research Group, Technical Research Laboratories, POSCO, 1 Goedong-dong, Nam-gu, Pohang, Gyeongbuk 790-785 (Korea, Republic of)


    Highlights: Black-Right-Pointing-Pointer Fine-grained AA6061-O was produced by a continuous hybrid process. Black-Right-Pointing-Pointer It consists of rolling, ECAP, and drawing. Black-Right-Pointing-Pointer High-strength bolt was manufactured with the fine-grained AA6061-O. Black-Right-Pointing-Pointer The UTS and micro-hardness of the bolt was increased by 50%. Black-Right-Pointing-Pointer The route C was better in making a uniform micro-hardness distribution in the bolt. - Abstract: It is well known that the development of a continuous manufacturing process to apply severe plastic deformation (SPD) is a major challenge for industrial usages to improve the mechanical properties of the material through grain refinement. In this study, fine-grained AA6061-O wire was manufactured by a two-pass hybrid process consisting of drawing, equal channel angular pressing and rolling in a continuous manner to investigate the effects of processing routes for two different routes, A and C, on the variation of ultimate tensile strength (UTS) and micro-hardness distribution. The UTS value (185 MPa) of the specimen processed by the two-pass hybrid process with route A was higher than that of 171 MPa obtained from the two-pass wire-drawing process and was equivalent to the level of 184 MPa processed by the three-pass wire-drawing process. The average micro-hardness value (Hv 58.0) obtained from the two-pass hybrid process through route C was the highest among all the cases. According to transmission electron microscopy, the original grain was subdivided and elongated owing to deformation during the processes. The specimen processed by the two-pass hybrid process through route C showed smaller deformation bands and had potentially higher angle grain boundaries compared to the specimen processed by the two-pass wire-drawing process. Finally, the high-strength bolt was manufactured using the fine-grained AA6061-O wire prepared by the continuous hybrid process to check its formability

  2. Mechanical Properties and Fracture Behaviour of LMD Produced 2.4682 and Wrought 2.4630 Dissimilar Welds

    Dahmen, Martin; Göbel, Marco

    A bearing made of Stellite 31 (2.4682) has to be welded onto a housing of Nimonic 75 (2.4630) by autogenous laser beam welding. The bearing part is produced by laser metal deposition (LMD), the housing consists of wrought sheet metal. An investigation is undertaken in order to study the effect of the anisotropy of the LMD part on the weld quality. Tensile specimens were produced and tested under varying load directions and test temperatures, and application of different weld heat treatments. The fractured specimens were analysed by metallography and fractography. Tensile tests at room temperature show a dependency of the fracture location and the mode of failure on the load direction with respect to the layer direction in conjunction with the heat treatment. At elevated temperature of 750° all specimens broke in the base material of 2.4630 in ductile fracture mode. Strength measured supersedes the values of either of the base materials.

  3. Adhesive strength and structure of micro-arc oxidation ceramic coatings grown in-situ on LY12 aluminum alloy

    WU Zhen-dong; JIANG Zhao-hua; YAO Zhong-ping


    The ceramic coatings containing zirconium dioxide were grown in-situ on LY12 aluminium alloy by micro-arc oxidation in mixed zirconate and phosphate solution. The phase composition and morphology of the coatings were studied by XRD and SEM.The adhesive strength of ceramic coatings was assessed by thermal shock test and tensile test. The results show that the coating is composed of m-ZrO2, t-ZrO2, and a little γ-Al2O3. Along the section of the coating, t-ZrO2 is more onboth sides than that in the middle, while m-ZrO2 is more in the middle than that on both sides. Meantime the coating is also composed of a dense layer and a loose layer. The coating has excellent thermal shock resistance under 550 ℃ and 600 ℃. And tensile tests show the adhesive strength of the dense layer of the coating with the substrate is more than 17.5 MPa.

  4. Semi-solid near-net shape rheocasting of heat treatable wrought aluminum alloys

    Curle, UA


    Full Text Available /OL]. catalog/pdf/alcoa_alloy_2024.pdf.3/18/2010. [35] ALCOA ALLOY 6082 [EB/OL]. materials%20specs/alloy%206082.pdf.3/18/2010. [36] ALCOA ALLOY 7075 [EB/OL]. catalog...

  5. Non-bridging Oxygen and Five-coordinated Aluminum in Aluminosilicate Glasses: A Cation Field Strength Study

    Thompson, L. M.; Stebbins, J. F.


    Linda M. Thompson Jonathan F. Stebbins Dept. of Geological and Environmental Sciences, Stanford University, Stanford CA 94305 Although it is understood in aluminosilicate melts and glasses that non-bridging oxygens (NBO) have significant influence on thermodynamic and transport properties, questions remain about its role and the extent of its influence, particularly in metaluminous and peraluminous compositions. One major question persists regarding whether the formation of NBO is in any way coupled with the formation of VAl (AlO5), which is significantly impacted by cation field strength (defined as the cation charge divided by the square of the distance between the cation and oxygen atoms) (Kelsey et al., 2009). Previous work on calcium and potassium aluminosilicate glasses has shown the presence of NBO on the metaluminous join and persisting into the peraluminous region, with significantly more NBO present in Ca glasses compared to K glasses of similar composition (Thompson and Stebbins, 2011). However, it is unclear if there is any systematic impact on NBO content by cation field strength similar to the impact on VAl. Expanding on the previous study, barium aluminosilicate glasses were synthesized covering a range of compositions crossing the metaluminous (e.g. BaAl2O4-SiO2) join to observe changes in the NBO for comparison against the calcium aluminosilicate glasses, thus looking at the impact of cation size on NBO versus cation charge. In the barium glasses on the 30 mol% SiO2 isopleth, the highest NBO content was 6.9% for the barium rich glass (R = 0.51, where R is Ba2+ / (Ba2+ + 2Al3+)) while the most peraluminous glass (R = 0.45) had an NBO content of 1.9%. Comparison of these results to earlier data shows these numbers are similar to what is observed in the Ca glasses, indicating cation size alone does not have a significant impact on NBO content. However the VAl content does show a decrease (compared to calcium aluminosilicate glasses at similar R values

  6. High-Temperature Cast Aluminum for Efficient Engines

    Bobel, Andrew C.

    both rod and plate-like precipitates. The model accurately accounts for the temperature dependence of particle nucleation and growth, solid solution strengthening, Si eutectic strength, and base aluminum yield strength. Strengthening model predictions of tensile yield strength are in excellent agreement with experimental observations over a wide range of aluminum alloy systems, aging temperatures, and test conditions. The developed models enable the prediction of the required particle morphology and volume fraction necessary to achieve target property goals in the design of future aluminum alloys. The effect of partitioning elements to the Q-phase was also considered for the potential to control the nucleation rate, reduce coarsening, and control the evolution of particle morphology. Elements were selected based on density functional theory (DFT) calculations showing the prevalence of certain elements to partition to the Q-phase. 3DAPT experiments were performed on Q-phase containing wrought alloys with these additions and show segregation of certain elements to the Q-phase with relative agreement to DFT predictions.

  7. Investigation of the structure/property relationship of spray-formed 7XXX series high-strength aluminum alloys and their metal matrix composites

    Sharma-Judd, Malavika M.


    The purpose of this investigation was to identify the structure/property relationship of spray formed 7XXX series alloys. High solute, ultra-high strength 7XXX series aluminum alloys with solute contents close to equilibrium solid solubility limits of the Al-Zn-Mg-Cu system have been produced by rapid solidification using spray deposition. The process yields massive preforms directly from the liquid state. Various elements, including chromium, manganese, silver, zirconium and scandium, were incorporated to produce a variety of microstructures and mechanical properties. SiC particulate was added to these same alloy compositions to produce metal matrix composites (MMCs). The resulting extruded products in the T6 and T7 conditions were evaluated and compared. Under peak-aged conditions in the unreinforced materials, strengths in excess of 860 MPa were achieved, with one alloy exceeding 900 MPa. Apart from the elongation to failure, the mechanical properties of the composite materials were equal to or superior to those of their unreinforced counterparts. The superior strength properties of the spray formed alloys were attributed to two major substructures with different scale; nanometer sized eta ' metastable precipitates and slightly larger, but finely distributed dispersoids. The large volume fraction of plate-like eta' precipitates (average size 58A, ranging up to 73 A in diameter) were identified as having a hexagonal structure with lattice parameters a = 0.488 nm and c = 1.376. The remarkable strengthening is predominantly attributed to precipitation hardening. The enhanced mechanical properties of the MMC materials are attributed to the increased dislocation density, and thus, a higher concentration of structural particles compared to the unreinforced materials. Higher gas-to-metal ratios of 4.45, as opposed to lower gas-to-metal ratios of 1.95 produced a refined grain structure with an evenly distributed second phase. In both unreinforced and MMC materials

  8. Deformation behavior and microstructure evolution of wrought magnesium alloys

    Wang, Shouren; Song, Linghui; Kang, Sukbong; Cho, Jaehyung; Wang, Yingzi


    There are many researches on the deformation behavior of wrought magnesium alloys, such as AZ31, AZ80, AZ91, and ZK60 magnesium alloys at different temperatures and strain rates, but few of them focuses on the deformation behavior of AZ41M and ZK60M alloys, especially under the twin-roll casting (TRC) state. Meanwhile, the existing researches only focus on the grain refinement law of the magnesium alloys under deformation conditions, the deformation mechanism has not been revealed yet. The hot compression behavior of AZ41M and ZK60M magnesium alloys under the temperature and strain rate ranges of 250-400 °C and 0.001-1 s-1 are studied by thermal simulation methods using Gleeble 1500 machine and virtual simulation using finite element analysis software. Simulation results show that sine hyperbolic law is the most suitable flow stress model for wider deformation conditions. The most reasonable selected deformation conditions of ZK60M alloy is 350 °C/0.1 s-1 for TRC and 350 °C/1 s-1 for conventional casting (CC), while AZ41M alloy is 300 °C/0.01 s-1 for TRC and 350 °C/0.1 s-1 for CC. Deformation behavior and dynamic recrystallization (DRX) mechanism of them are analyzed at the same deformation conditions. The microstructures of AZ41M and ZK60M alloys are observed at different deformed conditions by optical microscopy (OM) and electron back scatter diffraction (EBSD) and it reveals the flow behavior and deformation mechanism of them. Working harden and work soften contribute to the activation of basal, non-basal slip systems which promote DRX. The proposed research reveals the deformation behavior and mechanism of the AZ41M and ZK 60M magnesium alloys and concludes their optimized deformation parameters and processes and provides a theory basis for their manufacturing and application.

  9. Hot ductility behavior of Incoloy 901 superalloy in the cast and wrought conditions

    Shore, Fatemeh Mohammadi; Morakabati, Maryam; Mahdavi, Rashid [AMR of Technology, Tehran (Iran, Islamic Republic of). Metallic Material Dept.


    Hot ductility was investigated in Incoloy 901 using hot tensile testing over a temperature range of 900 to 1200 C and at strain rates of 0.01 to 1 s{sup -1}, in the cast and wrought conditions. Maximum ductility was detected in the cast and wrought conditions at temperature ranges of 1000 to 1050 C and 1000 to 1100 C, respectively. More voids were seen at the fracture surface of the wrought specimens compared to the cast ones. At 950 C, the formation of large and non-homogeneous voids at the fracture surface, as well as the appearance of transgranular and intergranular cracks in the wrought specimen, support moderate ductility of the alloy. Microstructural analysis does not support the occurrence of dynamic recrystallization in the cast specimens. In contrast, dynamic recrystallization in the wrought specimens at the region of maximum hot ductility promoted diffusion, leading to ductile fracture. At temperatures higher than the maximum ductility range, the formation of intergranular cracks resulted in a remarkable decline in ductility. (orig.)

  10. Investigation of Corrosion Behavior of Wrought Stellite Alloys

    Zhang, Xiaozhou

    The corrosion behavior of two wrought Stellite alloys, Stellite 6B and Stellite 6K, is studied under polarization test and immersion test. Two types of corrosive media, 3.5 wt% sodium chloride (NaCl) aqueous solution and Green Death solution, are used in the polarization test. Both potentiodynamic polarization and cyclic polarization testes are performed to investigate general and localized corrosion resistance of these alloys. Immersion tests of the two alloys are conducted in Green Death solution to determine Critical Pitting Temperature (CPT), mass loss, thickness change and the Extreme Value (minimum thickness) of the Extreme Value Analysis (EVA) model which derived from the Gumbel Distribution. The minimum thickness for Stellite 6B and Stellite 6K that is required for an assumed service time is predicted. Maximum pit depths, which are the input of the EVA model, are measured using a surface texture and contour measuring instrument. A Scanning Electron Microscope (SEM) with Energy Dispersive X-ray (EDX) spectrum is utilized to analyze the chemical composition of the corrosion products (pits). The CPTs of Stellite 6B and Stellite 6K in Green Death solution are determined to be all 60°C. The experimental results demonstrate that Stellite 6B and Stellite 6K have good general and localized corrosion resistance by forming the protective Cr-oxide film. However, the presence of carbides generates potential in the electrochemical reaction, causing corrosion of the alloys in the solution. The larger the carbide volume fraction is, the more the pits are forming in the alloy. Carbide size affects maximum pit depths; the larger the carbide size is, the bigger and deeper the pits are. The EDX analysis results of pits show large amount of oxygen in the carbide phase and small amount of oxygen in the solid solution phase. The Cr-rich carbides react with oxygen forming Cr-rich carbonates which are easily brittle, loose and broken, while Cr in the solid solution reacts with

  11. The aluminum smelting process.

    Kvande, Halvor


    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development.



    The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.

  13. Dynamic compressive response of wrought and additive manufactured 304L stainless steels

    Nishida Erik


    Full Text Available Additive manufacturing (AM technology has been developed to fabricate metal components that include complex prototype fabrication, small lot production, precision repair or feature addition, and tooling. However, the mechanical response of the AM materials is a concern to meet requirements for specific applications. Differences between AM materials as compared to wrought materials might be expected, due to possible differences in porosity (voids, grain size, and residual stress levels. When the AM materials are designed for impact applications, the dynamic mechanical properties in both compression and tension need to be fully characterized and understood for reliable designs. In this study, a 304L stainless steel was manufactured with AM technology. For comparison purposes, both the AM and wrought 304L stainless steels were dynamically characterized in compression Kolsky bar techniques. They dynamic compressive stress-strain curves were obtained and the strain rate effects were determined for both the AM and wrought 304L stainless steels. A comprehensive comparison of dynamic compressive response between the AM and wrought 304L stainless steels was performed. SAND2015-0993 C.

  14. Low temperature aluminum soldering analysis

    Peterkort, W.G.


    The investigation of low temperature aluminum soldering included the collection of spread factor and dihedral angle data for several solder alloys and a study of flux effects on aluminum. Selected solders were subjected to environmental tests and evaluated on the basis of tensile strength, joint resistance, visual appearance, and metallurgical analysis. A production line method for determining adequate flux removal was developed.

  15. 高强度合金结构钢与高强度铝合金防护层的耐霉性研究%Mould Resistance of Protective Layer on High-strength Alloy Structural Steel and High-strength Aluminum Alloy

    赵立华; 段渝平


    ABSTRACT:Objective To study the mould resistance of protective layers on high-strength alloy structural steel and high-strength aluminum alloy. Methods Different protective layers were prepared on high-strength alloy structural steel and high-strength aluminum alloy. Laboratory mould tests were carried out according to GJB 150.10A-2009 to evaluate the mould growth level on the protective layers. Results The mold levels of lubricant coating and anode oxidation layer on high-strength alloy structural steel and high-strength aluminum alloy were in the range of grade 0~1;the mold level of gun oil coating, paint coating, zinc layer or zinc nickel alloy layer moldy grade were in the range of grade 2~3. Conclusion For high-strength alloy structural steel substrate, lubricant coating had good mould resistance, while galvanized layer or zinc alloy layer, paint coating and gun oil coating had poor mould resistance. Forhigh-strength aluminum alloy substrate, anode oxidation layer had good mould resistance, while gun oil coating and paint coating had poor mould resistance.%目的:研究高强合金结构钢和高强铝合金防护层的耐霉菌腐蚀能力。方法以高强合金结构钢和高强铝合金两种材料为基材分别制备不同防护层,按GJB 150.10A—2009进行实验室霉菌试验,评定防护层的长霉等级。结果两种材料的不同防护层中,除润滑油涂层和阳级氧化层的长霉等级为0~1级外,炮油涂层、涂漆层、镀锌层或锌镍合金层长霉等级均在2~3级。结论高强合金结构钢润滑油涂层耐霉性能良好,镀锌层或锌镍合金层、涂漆层、炮油涂层耐霉性能较差;高强铝合金阳级氧化层耐霉性能良好,炮油涂层、涂漆层耐霉性能较差。

  16. Effects of Process Conditions on the Mechanical Behavior of Aluminium Wrought Alloy EN AW-2219 (AlCu6Mn Additively Manufactured by Laser Beam Melting in Powder Bed

    Michael Cornelius Hermann Karg


    Full Text Available Additive manufacturing is especially suitable for complex-shaped 3D parts with integrated and optimized functionality realized by filigree geometries. Such designs benefit from low safety factors in mechanical layout. This demands ductile materials that reduce stress peaks by predictable plastic deformation instead of failure. Al–Cu wrought alloys are established materials meeting this requirement. Additionally, they provide high specific strengths. As the designation “Wrought Alloys” implies, they are intended for manufacturing by hot or cold working. When cast or welded, they are prone to solidification cracks. Al–Si fillers can alleviate this, but impair ductility. Being closely related to welding, Laser Beam Melting in Powder Bed (LBM of Al–Cu wrought alloys like EN AW-2219 can be considered challenging. In LBM of aluminium alloys, only easily-weldable Al–Si casting alloys have succeeded commercially today. This article discusses the influences of boundary conditions during LBM of EN AW-2219 on sample porosity and tensile test results, supported by metallographic microsections and fractography. Load direction was varied relative to LBM build-up direction. T6 heat treatment was applied to half of the samples. Pronounced anisotropy was observed. Remarkably, elongation at break of T6 specimens loaded along the build-up direction exceeded the values from literature for conventionally manufactured EN AW-2219 by a factor of two.

  17. Wrought Cr--W--V bainitic/ferritic steel compositions

    Klueh, Ronald L.; Maziasz, Philip J.; Sikka, Vinod Kumar; Santella, Michael L.; Babu, Sudarsanam Suresh; Jawad, Maan H.


    A high-strength, high-toughness steel alloy includes, generally, about 2.5% to about 4% chromium, about 1.5% to about 3.5% tungsten, about 0.1% to about 0.5% vanadium, and about 0.05% to 0.25% carbon with the balance iron, wherein the percentages are by total weight of the composition, wherein the alloy is heated to an austenitizing temperature and then cooled to produce an austenite transformation product.

  18. On Corrosion of Ferrous in Typical Indian Soils-Part II Wrought Iron

    Brajendra Nath Tripathi


    Full Text Available Corrosion of wrought iron in ten Indian soils, employing Schwerdtfeger's soil corrosion cell procedure has been studied. The corrosion of wrought iron n non-acidic solid proceeds through electrochemical mechanism. Usually the rate of corrosion is maximum at the beginning and with the development of the film of the common products, the rate gradually decreases with time until it becomes more or less constant . In most of the cases 'uneven' general or local corrosion with pittings is observed. The maximum penetration is directly proportional to the corrodibility. Soils having moisture equivalent in the range 25-30% are most corrosive. The corrosivity of soils increases with increase in the concentration of soluble electrolytes. Ferric oxide present in laterite soil functions as a cathodic depolariser and hence increase the corrosivity. In and acidic sol the corrosion mainly proceeds through the mechanism of direct chemical reaction . The results have also been analyzed and correlated with various factors.

  19. A Short review on wrought austenitic stainless steels at high temperatures: processing, microstructure, properties and performance

    Ronald Lesley Plaut


    Full Text Available Wrought austenitic stainless steels are widely used in high temperature applications. This short review discusses initially the processing of this class of steels, with emphasis on solidification and hot working behavior. Following, a brief summary is made on the precipitation behavior and the numerous phases that may appear in their microstructures. Creep and oxidation resistance are, then, briefly discussed, and finalizing their performance is compared with other high temperature metallic materials.

  20. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    Royster, D. M.; Thomas, J. R.; Singleton, O. R.


    Aluminum alloy sheet exhibits high tensile and Kahn tear strengths. Rapid solidification of aluminum alloys in powder form and subsequent consolidation and fabrication processes used to tailor parts made of these alloys to satisfy such specific aerospace design requirements as high strength and toughness.

  1. Influences of post weld heat treatment on tensile strength and microstructure characteristics of friction stir welded butt joints of AA2014-T6 aluminum alloy

    Rajendran, C.; Srinivasan, K.; Balasubramanian, V.; Balaji, H.; Selvaraj, P.


    Friction stir welded (FSWed) joints of aluminum alloys exhibited a hardness drop in both the advancing side (AS) and retreating side (RS) of the thermo-mechanically affected zone (TMAZ) due to the thermal cycle involved in the FSW process. In this investigation, an attempt has been made to overcome this problem by post weld heat treatment (PWHT) methods. FSW butt (FSWB) joints of Al-Cu (AA2014-T6) alloy were PWHT by two methods such as simple artificial aging (AA) and solution treatment followed by artificial aging (STA). Of these two treatments, STA was found to be more beneficial than the simple aging treatment to improve the tensile properties of the FSW joints of AA2014 aluminum alloy.

  2. Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

    Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J.


    During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter parts have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites.

  3. Lightweight Aluminum/Nano composites for Automotive Drive Train Applications

    Chelluri, Bhanumathi; Knoth, Edward A.; Schumaker, Edward J.


    During Phase I, we successfully processed air atomized aluminum powders via Dynamic Magnetic Compaction (DMC) pressing and subsequent sintering to produce parts with properties similar to wrought aluminum. We have also showed for the first time that aluminum powders can be processed without lubes via press and sintering to 100 % density. This will preclude a delube cycle in sintering and promote environmentally friendly P/M processing. Processing aluminum powders via press and sintering with minimum shrinkage will enable net shape fabrication. Aluminum powders processed via a conventional powder metallurgy process produce too large a shrinkage. Because of this, sinter parts have to be machined into specific net shape. This results in increased scrap and cost. Fully sintered aluminum alloy under this Phase I project has shown good particle-to-particle bonding and mechanical properties. We have also shown the feasibility of preparing nano composite powders and processing via pressing and sintering. This was accomplished by dispersing nano silicon carbide (SiC) powders into aluminum matrix comprising micron-sized powders (<100 microns) using a proprietary process. These composite powders of Al with nano SiC were processed using DMC press and sinter process to sinter density of 85-90%. The process optimization along with sintering needs to be carried out to produce full density composites.

  4. 6082-T6高强铝合金材料本构模型试验研究%Experimental study on constitutive model of high-strength aluminum alloy 6082-T6

    王誉瑾; 范峰; 钱宏亮; 翟希梅


    铝合金材料本构关系是铝合金结构分析和应用的基本问题之一,针对国产高强新牌号铝合金6082-T6的材料本构模型进行研究.对取自3种截面形式结构用6082-T6高强铝合金型材的90个材性试样进行了拉伸试验,统计规定非比例延伸强度、抗拉强度、弹性模量、断裂伸长率、泊松比等材料力学参数.分析Ramberg-Osgood本构模型中硬化指数n的各种计算方法,提出采用快速退火算法(fast simulated annealing,FSA)求解n的方法并且编制计算程序,从而获得,n的置信区间,所得结果比传统两点法更稳定.在此基础上得到了国产6082-T6高强铝合金材料本构模型,与试验实测应力-应变曲线的比较表明,提出的本构模型具有很好的预测性,可为铝合金结构的工程应用提供参考.%Material constitutive relationship is one of the basic problems for analysis and application of aluminum alloy structures.This paper systematically studied the material constitutive model of the domestic high-strength new grade aluminum alloy 6082-T6.Tensile testing was conducted for a total of 90 coupons that were cut from three cross-section shapes of the aluminum alloy 6082-T6.The measurement and statistical analysis of mechanical parameters were carried out,including non-proportional extension strengths,tensile strength,elastic modulus,breaking elongation,Poisson' s ratio,etc.Various methods for calculating hardening exponent n in the Ramberg-Osgood law were discussed.The fast simulated annealing (FSA) method for calculating n was proposed and the FSA code was written to obtain the confidence interval of n.Comparison of results between FSA and other methods indicates that the FSA can provide more stable results than the traditional two-point method.On this basis,the material constitutive model of the 6082-T6 aluminum alloy was obtained.The comparison of this model and the tested stress-strain curve demonstrates that the constitutive model

  5. Microstructure and Strength of Laser Welds of Sub-micron Particulate-reinforced Aluminum Martix Composite Al2O3p/6061Al


    The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al2O3p/6061Al and the weldability of the material were studied.Experimental results indicated that because of the huge specific surface area of the reinforcement,the interfacial reaction between the matrix and the reinforcement was restrained intensively at elevated temperature and pulsed laser beam.The main factor affecting the weldability of the composite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the solidification of the molten pool.The laser pulse frequency directly affected the reinforcement segregation and the reinforcement distribution in the weld,so that the weldability of the composite could be improved by increasing the laser pulse frequency.On the bases of this,a satisfactory welded joint of sub-micron particulate-reinforced aluminum matrix composite Al2Op/6061Al was obtained by using appropriate welding parameters.

  6. First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys

    LIAO Fei


    Full Text Available Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH decreases in the order MgZn2 > Al2Cu > Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.

  7. Spot welding of mid-high strength aluminum alloys for aeronautic industry%航空用中、高强度铝合金点焊工艺

    张学军; 李艳; 张文扬


    Some kinds of spot welding processes of mid-high strength aluminum alloys parts such as the plate with large thickness ratio,dissimilar aluminum alloys,bent plates and undercoating plate were studied,respectively. The characteristics and difficulties were analyzed for different spot welding processes. The results show that the heat generation and radiation from the contacting zones can be controlled effectively with the formation of the nugget in a suitable size through the appropriate adjustments of the welding parameters and the size of electrodes. It is necessary for the spot welding process with undercoating to exert the pre-pressure to squeeze the undercoating out of the contact zones.%针对航空用中、高强铝合金结构件的大厚度比铝合金点焊、异种铝合金点焊、弯板结构点焊、涂底漆点焊,分析了构件点焊工艺特点和难点.研究表明:通过调整焊接参数和电极尺寸能有效地控制接触面的产热-散热情况,从而获得尺寸合适的熔核;对涂底漆点焊,焊前应施加预压力将底漆从接触面排走.

  8. Wrought stainless steel compositions having engineered microstructures for improved heat resistance

    Maziasz, Philip J [Oak Ridge, TN; Swindeman, Robert W [Oak Ridge, TN; Pint, Bruce A [Knoxville, TN; Santella, Michael L [Knoxville, TN; More, Karren L [Knoxville, TN


    A wrought stainless steel alloy composition includes 12% to 25% Cr, 8% to 25% Ni, 0.05% to 1% Nb, 0.05% to 10% Mn, 0.02% to 0.15% C, 0.02% to 0.5% N, with the balance iron, the composition having the capability of developing an engineered microstructure at a temperature above C. The engineered microstructure includes an austenite matrix having therein a dispersion of intragranular NbC precipitates in a concentration in the range of 10.sup.10 to 10.sup.17 precipitates per cm.sup.3.

  9. Rapidly solidified aluminum alloy powder

    Cho, S.S.; Chun, B.S.; Won, C.W.; Lee, B.S.; Kim, H.K.; Ryu, M. [Chungnam National Univ., Taejon (Korea, Republic of); Antolovich, S.D. [Washington State Univ., Pullman, WA (United States)


    Miniaturization and weight reduction are becoming increasingly important in the fabrication of vehicles. In particular, aluminum-silicon alloys are the logical choice for automotive parts such as pistons and cylinders liners because of their excellent wear resistance and low coefficient of thermal expansion. However, it is difficult to produce aluminum-silicon alloys with silicon contents greater than 20 wt% via ingot metallurgy, because strength is drastically reduced by the coarsening of primary silicon particles. This article describes an investigation of rapid solidification powder metallurgy techniques developed in an effort to prevent coarsening of the primary silicon particles in aluminum-silicon alloys.

  10. Analysis of methods for determining high cycle fatigue strength of a material with investigation of titanium-aluminum-vanadium gigacycle fatigue behavior

    Pollak, Randall D.

    Today, aerospace engineers still grapple with the qualitative and quantitative understanding of fatigue behavior in the design and testing of turbine-driven jet engines. The Department of Defense has taken a very active role in addressing this problem with the formation of the National High Cycle Fatigue Science & Technology Program in 1994. The primary goal of this program is to further the understanding of high cycle fatigue (HCF) behavior and develop methods in order to mitigate the negative impact of HCF on aerospace operations. This research supports this program by addressing the fatigue strength testing guidance currently provided by the DoD to engine manufacturers, with the primary goal to investigate current methods and recommend a test strategy to characterize the fatigue strength of a material at a specified number of cycles, such as the 109 design goal specified by MIL-HDBK-1783B, or range of cycles. The research utilized the benefits of numerical simulation to initially investigate the staircase method for use in fatigue strength testing. The staircase method is a commonly used fatigue strength test, but its ability to characterize fatigue strength variability is extremely suspect. A modified staircase approach was developed and shown to significantly reduce bias and scatter in estimates for fatigue strength variance. Experimental validation of this proposed test strategy was accomplished using a dual-phase Ti-6Al-4V alloy. The HCF behavior of a second material with a very different microstructure (beta annealed Ti-6Al-4V) was also investigated. The random fatigue limit (RFL) model, a recently developed analysis tool, was investigated to characterize stress-life behavior but found to have difficulty representing fatigue life curves with sharp transitions. Two alternative models (bilinear and hyperbolic) were developed based on maximum likelihood methods to better characterize the Ti-6Al-4V fatigue life behavior. These models provided a good fit to the

  11. Texture evolution in upset-forged P/M and wrought tantalum: Experimentation and modeling

    Bingert, J.F.; Desch, P.B.; Bingert, S.R.; Maudlin, P.J.; Tome, C.N.


    Preferred orientations in polycrystalline materials can significantly affect their physical and mechanical response through the retention of anisotropic properties inherent to the single crystal. In this study the texture evolution in upset-forged PIM and wrought tantalum was measured as a function of initial texture, compressive strain, and relative position in the pressing. A <001>/<111> duplex fiber texture parallel to the compression axis was generally observed, with varying degrees of a radial component evident in the wrought material. The development of deformation textures derives from restricted crystallographic slip conditions that generate lattice rotations, and these grain reorientations can be modeled as a function of the prescribed deformation gradient. Texture development was simulated for equivalent deformations using both a modified Taylor approach and a viscoplastic self-consistent (VPSC) model. A comparison between the predicted evolution and experimental results shows a good correlation with the texture components, but an overly sharp prediction at large strains from both the Taylor and VPSC models.

  12. Dynamic behaviors of historical wrought iron truss bridges: a field testing case study

    Dai, Kaoshan; Wang, Ying; Hedric, Andrew; Huang, Zhenhua


    The U.S. transportation infrastructure has many wrought iron truss bridges that are more than a century old and still remain in use. Understanding the structural properties and identifying the health conditions of these historical bridges are essential to deciding the maintenance or rebuild plan of the bridges. This research involved an on-site full-scale system identification test case study on the historical Old Alton Bridge (a wrought iron truss bridge built in 1884 in Denton, Texas) using a wireless sensor network. The study results demonstrate a practical and convenient experimental system identification method for historical bridge structures. The method includes the basic steps of the in-situ experiment and in-house data analysis. Various excitation methods are studied for field testing, including ambient vibration by wind load, forced vibration by human jumping load, and forced vibration by human pulling load. Structural responses of the bridge under these different excitation approaches were analyzed and compared with numerical analysis results.

  13. Effect of Weld Characteristic on Mechanical Strength of Laser-Arc Hybrid-Welded Al-Mg-Si-Mn Aluminum Alloy

    Zhang, Chen; Gao, Ming; Jiang, Ming; Zeng, Xiaoyan


    Laser-arc hybrid welding (LAHW) was employed to improve the tensile properties of the joints of 8-mm-thick Al-Mg-Si-Mn alloy (AA6082) using Al-5Mg filler wire. The weld microstructures were examined by scanning electron microscope, electron backscattered diffraction, and transmission electron microscopy in detail. The LAHW joints with pore-free and high-tensile performances were obtained. The strength enhancement of the fusion zone and heat-affected zone in the LAHW joint was mainly attributed to the grain refinement strengthening and the precipitation strengthening, respectively. The microstructure characteristics were related to the effects of laser-arc interaction on the energy transfer within the molten pool. The arc caused the majority of laser energy to dissipate out of the keyhole, and then it reduced the heat input. The lower heat input refined the grain size, weakened the overaging effect, and thus improved the tensile strength.

  14. Study of Local Cold Working and Tensile Test for 7050 High Strength Aluminum Alloy Hole Plate%7050高强铝合金孔板的挤压强化与拉伸试验研究

    范娟; 李付国; 李江; 王少刚


    This paper mainly aims at 7050 aluminum alloy to study the tensile mechanical performance of the plate with hole through testing and finite-element simulation. Then the cold working effects of different interferences (ranging from 0% to 11.11%) were compared and analyzed. Results show that compared with the standard specimens of 7050 aluminum alloy, for the plates with holes, their apparent strength, coefficient of elongation and modulus of elasticity are reduced, but the strains at plastic instability points are improved to a large extent. Cold working enhances the yield strength of the material around hole wall and improves the stress state of hole surface which make for peak stress weakened and enlarge the plane strain range along thickness direction of the hole. Meanwhile, the change of the tensile fracture with the cold working deformation degree present a regularity. Residual stress increases with interference increasing, and the position of peak stress transfers far from the wall of the hole along radial direction with interference increasing.%针对航空用7050高强铝合金的孔板件拉伸性能进行试验研究与模拟分析,并对不同过盈量(0%~11.11%)的孔挤压强化效果进行了对比分析.研究表明:孔板的表观强度、延伸率和弹性模量均降低,但塑性失稳点应变却有很大程度的提高;孔挤压强化提高了孔壁处材料的屈服强度,改善了孔表面的受力状态,使得应力峰值得到钝化,并扩大了孔壁沿厚度方向的平面应变范围,因此拉伸断口随孔挤压量的变化呈规律性的变化;孔挤压强化后残余拉、压应力峰值随挤压量的增加而增加,且其峰值出现的部位随挤压量的增加而向远离于孔壁的深处转移.

  15. Austenite stabilization and high strength-elongation product of a low silicon aluminum-free hot-rolled directly quenched and dynamically partitioned steel

    Tan, Xiao-Dong [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Xu, Yun-Bo, E-mail: [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Yang, Xiao-Long; Hu, Zhi-Ping; Peng, Fei [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Ju, Xiao-Wei [Ceri Long Product Co., Ltd., Beijing 100176 (China); Wu, Di [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China)


    Microstructures composed of lath martensite and retained austenite with volume fraction between 8.0 vol.% and 12.0 vol.% were obtained in a low-C low-Si Al-free steel through hot-rolling direct quenching and dynamical partitioning (HDQ&DP) processes. The austenite stabilization mechanism in the low-C low-Si Al-free steel under the special dynamical partitioning processes is investigated by analyzing the carbon partition behavior from martensite to austenite and the carbide precipitation-coarsening behavior in martensite laths combining with the possible hot rolling deformation inheritance. Results show that the satisfying retained austenite amount in currently studied low-Si Al-free HDQ&DP steel is caused by the high-efficiency carbon enrichment in the 30–80 nm thick regions of austenite near the interfaces in the hot-rolled ultra-fast cooled structure and the avoidance of serious carbides coarsening during the continuous cooling procedures. The excellent strength-elongation product reaching up to 26,000 MPa% shows that the involved HDQ&DP process is a promising method to develop a new generation of advanced high strength steel. - Highlights: • HDQ&DP processes were applied to a low-C low-Si Al-free steel. • Effective partitioning time during the continuous cooling processes is 1–220 s. • Retained austenite with volume fraction between 8.0 vol. % and 12.0 vol. % has been obtained. • The special austenite stabilization mechanism has been expounded.

  16. Electrochemical Study of Corrosion Behavior of Wrought Stellite Alloys in Sodium Chloride and Green Death Solutions

    Zhang, X. Z.; Liu, R.; Chen, K. Y.; Yao, M. X.; Collier, R.


    Corrosion behavior of wrought Stellite 6B and Stellite 6K, which have similar chemical composition but contain different carbon content, in 3.5 wt.% NaCl solution and in Green Death solution is investigated using various electrochemical methods, including potentiodynamic polarization, cyclic polarization, and electrochemical impedance spectroscopy (EIS). The obtained potentiodynamic polarization curves, cyclic polarization curves, and EIS spectra for these alloys are in good agreement, showing that Stellite 6K with higher carbon content is easier corroded due to its larger volume fraction of carbides but the Cr2O3 film formed on this alloy is stronger and more stable than that on Stellite 6B. Further immersion tests on these alloys show that Stellite 6K has less resistance to pitting corrosion.

  17. Effects of heat-treatment on microstructure of wrought magnesium alloy ZK60

    MA Yan-long; PAN Fu-sheng; ZUO Ru-lin; ZHANG Jin; YANG Ming-bo


    The microstructure of the as-cast, as-solution-treated and as-aged wrought magnesium alloy ZK60 was studied. The results indicate that the microstructure of the as-cast ZK60 alloy is mainly composed of network eutectic (α-Mg+MgZn) and divorced eutectic MgZn, which semi-continuously distribute along the grain boundaries or in the interdendritic area and almost dissolve into the matrix after solid solution treatment. The Laves phase MgZn2 is not sensitive to the heat treatment and seems to form at the early stage of solidification and keeps its size and shape till the aging stage. It is believed that the occurrence of the Laves phase in the ZK60 alloy would possibly contribute to the defects. Many new phases, including MgZn phase which is different from that forms during eutectic reaction, precipitate after aging treatment.

  18. Effect of the strain-induced melt activation (SIMA) process on the tensile properties of a new developed super high strength aluminum alloy modified by Al-5Ti-1B grain refiner

    Haghparast, Amin [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Nourimotlagh, Masoud [Young Researchers Club, Dareshahr Branch, Islamic Azad university (Iran, Islamic Republic of); Alipour, Mohammad, E-mail: [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)


    In this study, the effect of Al-5Ti-1B grain refiners and modified strain-induced melt activation process on an Al-Zn-Mg-Cu alloy was studied. The optimum level of Ti was found to be 0.1 wt.%. The specimens subjected to deformation ratio of 40% (at 300 Degree-Sign C) and various heat treatment times (10-40 min) and temperature (550-600 Degree-Sign C) regimes were characterized in this study. Reheating condition to obtain a fine globular microstructure was optimized. Microstructural examinations were conducted by optical and scanning electron microscopy coupled with an energy dispersive spectrometry. The optimum temperature and time in strain-induced melt activation process are 575 Degree-Sign C and 20 min, respectively. T6 heat treatment including quenching to room temperature and aging at 120 Degree-Sign C for 24 h was employed to reach to the maximum strength. Significant improvements in mechanical properties were obtained with the addition of grain refiner combined with T6 heat treatment. After the T6 heat treatment, the average tensile strength increased from 283 MPa to 587 and 332 MPa to 617 for samples refined with 2 wt.% Al-5Ti-1B before and after strain-induced melt activation process and extrusion process, respectively. Ultimate strength of Ti-refined specimens without SIMA process has a lower value than globular microstructure specimens after SIMA and extrusion process. - Highlights: Black-Right-Pointing-Pointer The effect of Al-5Ti-1B on the aluminum alloy produced by SIMA process was studied. Black-Right-Pointing-Pointer Al-5Ti-1B is an effective in reducing the grain and reagent fine microstructure. Black-Right-Pointing-Pointer Reheating condition to obtain a fine globular microstructure was optimized. Black-Right-Pointing-Pointer The optimum temperature and time in SIMA process are 575 Degree-Sign C and 20 min respectively. Black-Right-Pointing-Pointer UTS of globular structure specimens have a more value than Ti-refined specimens.

  19. 固溶处理对7050铝合金强度和断裂韧性的影响%Influence of solution heat treatment on strength and fracture toughness of aluminum alloy 7050

    韩念梅; 张新明; 刘胜胆; 何道广; 张荣


    The influences of the solution heat treatment on the tensile properties and fracture toughness of the 7050 aluminum alloy were investigated by means of optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), the ambient temperature tensile tests and compact tension toughness testes. The results show that during the single-stage solution heat treatment, with the increase of solution temperature, coarse constituent particles are dissolved, and meanwhile, the percentage of recrystallization and the size of the subgrains increase. With the increase of solution temperature, the strength and fracture toughness firstly increase and then decrease. The two-stage solution heat treatment results in improved dissolution of coarse constituent particles, low recrystallization percentage and small size of subgrains. The strength and fracture toughness during the two-stage solution heat treatment are larger than the maximum of the single-stage solution heat treatment. The percentage of recrystallization and the size of the subgrains are small after pre-precipitation following solution heat treatment, but a large number of η phase aggregates at the subgrain boundary. Meanwhile, constituent particles dissolve out again from the matrix, which leads to the decrease of the strength and fracture toughness.%采用金相显微镜、扫描电镜、透射电镜、常温拉伸、紧凑拉伸等实验手段研究固溶处理对7050铝合金拉伸力学性能和断裂韧性的影响.研究结果表明:单级固溶中,随着固溶温度的升高,粗大第二相逐渐溶解,但再结晶体积分数和亚晶尺寸逐渐增大,导致强度和断裂韧性均先增大后减小;双级固溶后,粗大第二相明显减少,再结晶体积分数和亚晶尺寸较小,强度和断裂韧性均超过单级固溶的最大值;固溶后预析出,虽然再结晶体积分数较低,亚晶尺寸较小,但亚晶界析出大量η相,基体内存在大量粗大第二相,

  20. Effect of silicon on recrystallization of wrought aluminium alloy%Si元素对变形铝合金再结晶影响

    华琪; 邵光杰


    Effects of silicon contents, deformation and solution treatment on hardness of the recrystalled wrought aluminum alloy were investigated by means of optical microscopy and hardness tests. The results show that coarse grain size in the aluminumsilicon alloy solutiontreated at 500 ℃ for 30 rain and followed by rapidly compressive deformation is obtained after annealingdue to the rapid deformation. Less silicon contents of alu, in inumsilicon alloy can accelerate the recrystallization and get the coarse grain. The addition of silicon significantly causes a reduction in recrystallization grain size when silicon content is greater than 1%.%围绕不同的成分、变形温度和变形量同再结晶退火后的合金硬度之间的关系,通过偏光显微组织分析以及硬度测试对铝硅合金变形再结晶进行了研究。结果表明,铝硅合金在500℃进行0~h固溶处理后以较快的速度进行变形会使得退火后再结晶晶粒尺寸变大。硅含量较少的时候可以促进铝硅合金再结晶的发生,并使再结晶晶粒粗化,而当硅含量大于1%之后,随着硅含量的增加再结晶晶粒会显著减小。

  1. Biocompatibility of metal injection molded versus wrought ASTM F562 (MP35N) and ASTM F1537 (CCM) cobalt alloys.

    Chen, Hao; Sago, Alan; West, Shari; Farina, Jeff; Eckert, John; Broadley, Mark


    We present a comparative analysis between biocompatibility test results of wrought and Metal Injection Molded (MIM) ASTM F562-02 UNS R30035 (MP35N) and F1537 UNS R31538 (CCM) alloy samples that have undergone the same generic orthopedic implant's mechanical, chemical surface pre-treatment, and a designed pre-testing sample preparation method. Because the biocompatibility properties resulting from this new MIM cobalt alloy process are not well understood, we conducted tests to evaluate cytotoxicity (in vitro), hemolysis (in vitro), toxicity effects (in vivo), tissue irritation level (in vivo), and pyrogenicity count (in vitro) on such samples. We show that our developed MIM MP35N and CCM materials and treatment processes are biocompatible, and that both the MIM and wrought samples, although somewhat different in microstructure and surface, do not show significant differences in biocompatibility.

  2. Welding of aluminum with linear ribbon explosives.

    Bement, L. J.


    A small-scale simplified, parallel plate process of welding aluminum with very small quantities of lead-sheathed linear ribbon RDX explosive is described. The results of the welding of five different alloys, obtained by using this technique, show that the weld strengths are up to 90% of the parent metal tensile strength.

  3. Long-Term Cyclic Oxidation Behavior of Wrought Commercial Alloys at High Temperatures

    Bingtao Li


    The oxidation resistance of a high-temperature alloy is dependent upon sustaining the formation of a protective scale, which is strongly related to the alloying composition and the oxidation condition. The protective oxide scale only provides a finite period of oxidation resistance owing to its eventual breakdown, which is especially accelerated under thermal cycling conditions. This current study focuses on the long-term cyclic oxidation behavior of a number of commercial wrought alloys. The alloys studied were Fe- and Ni-based, containing different levels of minor elements, such as Si, Al, Mn, and Ti. Oxidation testing was conducted at 1000 and 1100 C in still air under both isothermal and thermal cycling conditions (1-day and 7-days). The specific aspects studied were the oxidation behavior of chromia-forming alloys that are used extensively in industry. The current study analyzed the effects of alloying elements, especially the effect of minor element Si, on cyclic oxidation resistance. The behavior of oxide scale growth, scale spallation, subsurface changes, and chromium interdiffusion in the alloy were analyzed in detail. A novel model was developed in the current study to predict the life-time during cyclic oxidation by simulating oxidation kinetics and chromium interdiffusion in the subsurface of chromia-forming alloys.

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

    YUAN Jiawei; PANG Yuhua; LI Ting


    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.

  5. Progress on high-performance rapid prototype aluminum mirrors

    Woodard, Kenneth S.; Myrick, Bruce H.


    Near net shape parts can be produced using some very old processes (investment casting) and the relatively new direct metal laser sintering (DMLS) process. These processes have significant advantages for complex blank lightweighting and costs but are not inherently suited for producing high performance mirrors. The DMLS process can provide extremely complex lightweight structures but the high residual stresses left in the material results in unstable mirror figure retention. Although not to the extreme intricacy of DMLS, investment casting can also provide complex lightweight structures at considerably lower costs than DMLS and even conventional wrought mirror blanks but the less than 100% density for casting (and also DMLS) limits finishing quality. This paper will cover the progress that has been made to make both the DMLS and investment casting processes into viable near net shape blank options for high performance aluminum mirrors. Finish and figure results will be presented to show performance commensurate with existing conventional processes.

  6. Environmental fatigue behaviors of wrought and cast stainless steels in 310 .deg. C Deoxygenated Water

    Cho, Pyung Yeon


    Environmental fatigue behaviors of wrought type 316LN stainless steel and cast CF8M stainless steel were investigated. LCF tests were performed at fixed strain rate of 0.04%/s with 0.4%, 0.6%, 0.8%, 1.0% strain amplitudes in 310 .deg. C deoxygenated water environment. In addition, to analyze microstructure effect on fatigue behavior, low cycle fatigue tests in air environment were performed at fixed strain rate of 0.4%/s, 0.04%/s with 0.4%, 0.8% strain amplitudes. It was shown that the low cycle fatigue life of CF8M in a 310 .deg. C deoxygenated water environment was slightly longer than that of 316LN. On the other hand, the low cycle fatigue life of CF8M in a 310 .deg. C air environment was slightly shorter than that of 316LN or was similar with that of 316LN. Through OM observation and phase image analysis, it was confirmed that the ferrite content of CF8M tested in a 310 .deg. C deoxygenated water environment was larger than that of CF8M tested in a 310 .deg. C air environment. It was shown that the ferrite phase fraction of CF8M tested in 310 .deg. C deoxygenated water environment was approximately 26∼28% and that of CF8M tested in air environment was approximately 10∼12%. The difference of ferrite content in CF8M results in superior tensile properties as higher ferrite content. Furthermore, the difference of ferrite content in CF8M might be the cause of different result of fatigue life between CF8M and 316LN depending on environment. In this study, focused on CF8M having 26∼28% ferrite content, to understand the causes of these differences in a 310 .deg. C deoxygenated water environment, fracture surface and crack morphology were observed. And material factors like microstructure, mechanical properties factors like stress behavior during fatigue life, factors by environmentally assisted cracking (EAC) like hydrogen induced cracking (HIC) and chemical compositions of both materials were analyzed. Mainly in a 310 .deg. C deoxygenated water environment, the

  7. Fracture criteria for automobile crashworthiness simulation of wrought aluminium alloy components

    El-Magd, E. [RWTH Aachen (Germany); Gese, H. [MATFEM, Munich (Germany); Tham, R. [Fraunhofer Inst. fuer Kurzzeitdynamik, Freiburg (Germany); Hooputra, H.; Werner, H. [BMW Group, Munich (Germany)


    In automobile crashworthiness simulation, the prediction of plastic deformation and fracture of each significant, single component is critical to correctly represent the transient energy absorption through the car structure. There is currently a need, in the commercial FEM community, for validated material fracture models which adequately represent this phenomenon. The aim of this paper is to compare and to validate existing numerical approaches to predict failure with test data. All studies presented in this paper were carried out on aluminium wrought alloys: AlMgSi1.F31 and AlMgSiCu-T6. A viscoplastic material law, whose parameters are derived from uniaxial tensile and compression tests at various strain rates, is developed and presented herein. Fundamental ductile fracture mechanisms such as void nucleation, void growth, and void coalescence as well as shear band fracture are present in the tested samples and taken into consideration in the development of the fracture model. Two approaches to the prediction of fracture initiation are compared. The first is based on failure curves expressed by instantaneous macroscopic stresses and strains (i.e. maximum equivalent plastic strain vs. stress triaxiality). The second approach is based on the modified Gurson model and uses state variables at the mesoscopic scale (i.e. critical void volume fraction). Notched tensile specimens with varying notch radii and axisymmetric shear specimens were used to produce ductile fractures and shear band fractures at different stress states. The critical macroscopic and mesoscopic damage values at the fracture initiation locations were evaluated using FEM simulations of the different specimens. The derived fracture criteria (macroscopic and mesoscopic) were applied to crashworthiness experiments with real components. The quality of the prediction on component level is discussed for both types of criteria. (orig.)

  8. Effects of two erbium-doped yttrium aluminum garnet lasers and conventional treatments as composite surface abrasives on the shear bond strength of metal brackets bonded to composite resins

    Sobouti, Farhad; Dadgar, Sepideh; Sanikhaatam, Zahra; Nateghian, Nazanin; Saravi, Mahdi Gholamrezaei


    Background: Bonding brackets to dental surfaces restored with composites are increasing. No studies to date have assessed the efficacy of laser irradiation in roughening of composite and the resulted shear bond strength (SBS) of the bonded bracket. We assessed, for the 1st time, the efficacy of two laser beams compared with conventional methods. Materials and Methods: Sixty-five discs of light-cured composite resin were stored in deionized distilled water for 7 days. They were divided into five groups of 12 plus a group of five for scanning electron microscopy (SEM): Bur-abrasion followed by phosphoric acid etching (bur-PA), hydrofluoric acid conditioning (HF), sandblasting, 3 W and 2 W erbium-doped yttrium aluminum garnet laser irradiation for 12 s. After bracket bonding, specimens were water-stored (24 h) and thermocycled (500 cycles), respectively. SBS was tested at 0.5 mm/min crosshead speed. The adhesive remnant index (ARI) was scored under ×10 magnification. SEM was carried out as well. Data were analyzed using analysis of variance (ANOVA), Kruskal–Wallis, Tukey, Dunn, one-sample t-test/Wilcoxon tests, and Weibull analysis (α =0.05). Results: The SBS values (megapascal) were bur-PA (11.07 ± 1.95), HF (19.70 ± 1.91), sandblasting (7.75 ± 1.10), laser 2 W (15.38 ± 1.38), and laser 3 W (20.74 ± 1.73) (compared to SBS = 6, all P = 0.000). These differed significantly (ANOVA P = 0.000) except HF versus 3 W laser (Tukey P > 0.05). ARI scores differed significantly (Kruskal–Wallis P = 0.000), with sandblasting and 2 W lasers having scores inclined to the higher end (safest debonding). Weibull analysis implied successful clinical outcome for all groups, except for sandblasting with borderline results. Conclusion: Considering its high efficacy and the lack of adverse effects bound with other methods, the 3 W laser irradiation is recommended for clinical usage. PMID:26998473

  9. Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation.

    Cao, Bingdi; Zhang, Weijun; Wang, Qiandi; Huang, Yangrui; Meng, Chenrui; Wang, Dongsheng


    Chemical conditioning is one of the most important processes for improve the performance of sludge dewatering device. Aluminum salt coagulant has been widely used in wastewater and sludge treatment. It is generally accepted that pre-formed speciation of aluminum salt coagulants (ASC) has an important influence on coagulation/flocculation performance. In this study, the interaction mechanisms between sludge particles and aluminum salt coagulants with different speciation of hydroxy aluminum were investigated by characterizing the changes in morphological and EPS properties. It was found that middle polymer state aluminum (Alb) and high polymer state aluminum (Alc) performed better than monomer aluminum and oligomeric state aluminum (Ala) in reduction of specific resistance to filtration (SRF) and compressibility of wastewater sludge due to their higher charge neutralization and formed more compact flocs. Sludge was significantly acidified after addition Ala, while pH was much more stable under Alb and Alc conditioning due to their hydrolysis stability. The size of sludge flocs conditioned with Alb and Alc was small but flocs structure was denser and more compact, and floc strength is higher, while that formed from Ala is relatively large, but floc structure was loose, floc strength is relatively lower. Scanning environmental microscope analysis revealed that sludge flocs conditioned by Alb and Alc (especially PAC2.5 and Al13) exhibited obvious botryoidal structure, this is because sludge flocs formed by Alb and Alc were more compact and floc strength is high, it was easy generated plentiful tiny channels for water release. In addition, polymeric aluminum salt coagulant (Alb, Alc) had better performance in compressing extracellular polymeric substances (EPS) structure and removing sticky protein-like substances from soluble EPS fraction, contributing to improvement of sludge filtration performance. Therefore, this study provides a novel solution for improving sludge

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


    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.

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

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


    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%.

  12. Manufacturing of Aluminum Composite Material Using Stir Casting Process

    Muhammad Hayat Jokhio


    Full Text Available Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of \\"Al2O3\\" particles in 7xxx aluminum matrix. The 7xxx series aluminum matrix usually contains Cu-Zn-Mg. Therefore, the present research was conducted to investigate the effect of elemental metal such as Cu-Zn-Mg in aluminum matrix on mechanical properties of stir casting of aluminum composite materials reinforced with alpha \\"Al2O3\\" particles using simple foundry melting alloying and casting route. The age hardening treatments were also applied to study the aging response of the aluminum matrix on strength, ductility and hardness. The experimental results indicate that aluminum matrix cast composite can be manufactured via conventional foundry method giving very good responses to the strength and ductility up to 10% \\"Al2O3\\" particles reinforced in aluminum matrix.

  13. Dry lubricant films for aluminum forming.

    Wei, J.; Erdemir, A.; Fenske, G. R.


    During metal forming process, lubricants are crucial to prevent direct contact, adhesion, transfer and scuffing of workpiece materials and tools. Boric acid films can be firmly adhered to the clean aluminum surfaces by spraying their methanol solutions and provide extremely low friction coefficient (about 0.04). The cohesion strengths of the bonded films vary with the types of aluminum alloys (6061, 6111 and 5754). The sheet metal forming tests indicate that boric acid films and the combined films of boric acid and mineral oil can create larger strains than the commercial liquid and solid lubricants, showing that they possess excellent lubricities for aluminum forming. SEM analyses indicate that boric acid dry films separate the workpiece and die materials, and prevent their direct contact and preserve their surface qualities. Since boric acid is non-toxic and easily removed by water, it can be expected that boric acid films are environmentally friendly, cost effective and very efficient lubricants for sheet aluminum cold forming.

  14. MIIT: Aluminum Processing Industry will Focus on Work in Four Aspects


    Aluminum processing is a key component of China’s nonferrous metals industry.After many years of rapid development,China has become the world’s biggest manufacturer and consumer of aluminum products,and its overall strength has improved obviously.In 2014,the output of China’s aluminum processing products reached

  15. Microstructures and properties of aluminum die casting alloys

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


    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.

  16. NASA-427: A New Aluminum Alloy

    Nabors, Sammy A.


    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.

  17. Aluminum extraction from aluminum industrial wastes

    Amer, A. M.


    Aluminum dross tailings, an industrial waste from the Egyptian Aluminum Company (Egyptalum), was used to produce two types of alums: aluminum sulfate alum (Al2(SO4)3·12H2O) and ammonium aluminum alum {(NH4)2SO4AL2 (SO4)3·24H2O}. This was carried out in two processes. The first involves leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of aluminum sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purified aluminum dross tailings thus produced. This was carried out in an autoclave. The effects of temperature, time of reaction, and acid concentration on pressure leaching and extraction processes were studied in order to specify the optimum conditions to be applied in the bench scale production as well as the kinetics of leaching process.




    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  19. Reuse of Aluminum Dross as an Engineered Product

    Dai, Chen; Apelian, Diran

    To prevent the leaching of landfilled aluminum dross waste and save the energy consumed by recovering metallic aluminum from dross, aluminum dross is reused as an engineering product directly rather than "refurbished" ineffectively. The concept is to reduce waste and to reuse. Two kinds of aluminum dross from industrial streams were selected and characterized. We have shown that dross can be applied directly, or accompanied with a simple conditioning process, to manufacture refractory components. Dross particles below 50 mesh are most effective. Mechanical property evaluations revealed the possibility for dross waste to be utilized as filler in concrete, resulting in up to 40% higher flexural strength and 10% higher compressive strength compared to pure cement, as well as cement with sand additions. The potential usage of aluminum dross as a raw material for such engineering applications is presented and discussed.

  20. Comparison of the heat treatment response of SSM-HPDC 6082 and 6004 wrought alloys with A356 and F357 casting alloys

    Müller, H


    Full Text Available alloys compared with the Al-Mg-Si wrought alloys has recently been highlighted [2]. In Al-Si-Mg alloys in general, the decomposition of the supersaturated solid solution (SSS) is believed to occur as follows [3]: SSS ? (Mg + Si)clusters / GP...


    刘文辉; 黄浩


    通过建立7.62mm穿甲弹侵彻铝合金板的模型,采用Johnson.Cook材料模型模拟研究了焊接接头的强度失配对铝合金板抗弹性能的影响。研究结果表明:当子弹侵彻铝合金焊接接头附近时,由于材料的不均匀变形,子弹会改变侵彻方向,其方向角的改变大小与子弹速度、侵入位置、弹头形状、强度失配比、靶板厚度有关;当子弹以低速侵彻铝合金板中间的软焊缝材料时,由于变形局部化,出现材料的抗弹性能低于纯焊缝材料的情况;由于子弹侵彻方向的改变,出现部分区域的抗弹性能高于铝合金基体材料的情况。研究结果为不均匀材料的抗弹性能研究提供参考。%To analyze the effect of strength mismatch on the ballistic performance of aluminum welded joint, a model of aluminum alloy plate penetrated by 7.62mm bullet was created, and the Johnson-Cook constitutive equation was adopted. Results show that the penetration direction will change due to the heterogeneous deformation as the projectile penetrates the aluminum weld joint, and the magnitude of angle change of penetration direction relates to the penetration position, impact velocity, projectile geometry, the rate of strength mismatch and target thickness. When the projectile only penetrates the region of weld seam at a small impact velocity, material's ballistic performance may be worse than that of pure weld seam material due to material deformation localization. There are some regions whose ballistic performances are better than that of aluminum base due to the change of penetration direction. It is useful for the ballistic performance analysis of heterogeneous materials.

  2. Microstructures and mechanical properties of high strength Mg-Zn-Mn alloy


    The microstructures and mechanical properties of a new Mg-6%Zn-1%Mn (mass fraction) wrought magnesium alloy were studied, which could be extruded smoothly at 310~330 ℃ with a complete dynamic recrystallization. After solution treatment one and two-step aging techniques were used. All as-aged mierostructures contained two types of dispersed phases: ,β phases and pure α-Mn particles. The two-step aging had a better strengthening effect than the traditional one-step aging, and the strength value achieved by the two-step aging could reach that of the ZK60 wrought magnesium alloy. The outstanding precipitation strengthening effect of the alloy should be attribute to the GP zones, diffusive solute-rich zones and some metastable phases formed during the first step aging that provide more effective nuclei for Mg-Zn strengthening phases during the second step aging.

  3. Development of deep drawn aluminum piston tanks

    Whitehead, J.C.; Bronder, R.L.; Kilgard, L.W.; Evans, M.C.; Ormsby, A.E.; Spears, H.R.; Wilson, J.D.


    An aluminum piston tank has been developed for applications requiring lightweight, low cost, low pressure, positive-expulsion liquid storage. The 3 liter (183 in{sup 3}) vessel is made primarily from aluminum sheet, using production forming and joining operations. The development process relied mainly on pressurizing prototype parts and assemblies to failure, as the primary source of decision making information for driving the tank design toward its optimum minimum-mass configuration. Critical issues addressed by development testing included piston operation, strength of thin-walled formed shells, alloy choice, and joining the end cap to the seamless deep drawn can. 9 refs., 8 figs.

  4. Modeling dissolution in aluminum alloys

    Durbin, Tracie Lee


    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

  5. 防锈铝板/镀锌钢板异种金属冷金属过渡熔钎焊接头的组织与抗拉强度%Microstructure and Tensile Strength of Rust-Proof Aluminum Plate and Zinc-Coated Steel Plates Braze-Weld Joint Prepared by Cold Metal Transfer

    冯曰海; 王克鸿; 高飞; 杜刚


    The cold metal transfer (CMT) brazing-welding process was used to weld dissimilar metals of LF21 rust-proof aluminum plate and DD51D+Z zinc-coated steel plate,and the microstructure and tensile strength of the joint were studied.The results show that the compound layer of middle interface zone of the braze-weld joint was intermetallic compound FeAla with thickness of 4-6 μm.The average transverse tensile strength of the joint was up to 77 MPa and strength coefficient was 0.6.%采用冷金属过渡(CMT)熔钎焊接工艺,对LF21防锈铝板和DD51D+Z镀锌钢板进行了异种金属的连接,对接头的显微组织和抗拉强度进行了研究.结果表明:防锈铝板和镀锌钢板的熔钎焊接头的中间界面区化合物为4~6 μm厚的FeAl3金属间化合物,接头的平均横向抗拉强度为77MPa,接头的强度系数为0.6.

  6. Aspects of aluminum toxicity

    Hewitt, C.D.; Savory, J.; Wills, M.R. (Univ. of Virginia Health Sciences Center, Charlottesville (USA))


    Aluminum is the most abundant metal in the earth's crust. The widespread occurrence of aluminum, both in the environment and in foodstuffs, makes it virtually impossible for man to avoid exposure to this metal ion. Attention was first drawn to the potential role of aluminum as a toxic metal over 50 years ago, but was dismissed as a toxic agent as recently as 15 years ago. The accumulation of aluminum, in some patients with chronic renal failure, is associated with the development of toxic phenomena; dialysis encephalopathy, osteomalacic dialysis osteodystrophy, and an anemia. Aluminum accumulation also occurs in patients who are not on dialysis, predominantly infants and children with immature or impaired renal function. Aluminum has also been implicated as a toxic agent in the etiology of Alzheimer's disease, Guamiam amyotrophic lateral sclerosis, and parkinsonism-dementia. 119 references.

  7. Aluminum powder metallurgy processing

    Flumerfelt, J.F.


    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.

  8. Is the Aluminum Hypothesis Dead?

    Lidsky, Theodore I.


    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed w...

  9. High energy density aluminum battery

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan


    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  10. High energy density aluminum battery

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan


    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  11. Friction Welding For Cladding Applications: Processing, Microstructure and Mechanical Properties of Inertia Friction Welds of Stainless Steel to Low Carbon Steel and Evaluation of Wrought and Welded Austenitic Stainless Steels for Cladding Applications in Acidchloride Service

    Switzner, Nathan

    Friction welding, a solid-state joining method, is presented as a novel alternative process step for lining mild steel pipe and forged components internally with a corrosion resistant (CR) metal alloy for petrochemical applications. Currently, fusion welding is commonly used for stainless steel overlay cladding, but this method is costly, time-consuming, and can lead to disbonding in service due to a hard martensite layer that forms at the interface due to partial mixing at the interface between the stainless steel CR metal and the mild steel base. Firstly, the process parameter space was explored for inertia friction butt welding using AISI type 304L stainless steel and AISI 1018 steel to determine the microstructure and mechanical properties effects. A conceptual model for heat flux density versus radial location at the faying surface was developed with consideration for non-uniform pressure distribution due to frictional forces. An existing 1 D analytical model for longitudinal transient temperature distribution was modified for the dissimilar metals case and to account for material lost to the flash. Microstructural results from the experimental dissimilar friction welds of 304L stainless steel to 1018 steel were used to discuss model validity. Secondly, the microstructure and mechanical property implications were considered for replacing the current fusion weld cladding processes with friction welding. The nominal friction weld exhibited a smaller heat softened zone in the 1018 steel than the fusion cladding. As determined by longitudinal tensile tests across the bond line, the nominal friction weld had higher strength, but lower apparent ductility, than the fusion welds due to the geometric requirements for neck formation adjacent to a rigid interface. Martensite was identified at the dissimilar friction weld interface, but the thickness was smaller than that of the fusion welds, and the morphology was discontinuous due to formation by a mechanism of solid

  12. Compressive Strength of EN AC-44200 Based Composite Materials Strengthened with α-Al2O3 Particles

    A. Kurzawa; J. W. Kaczmar


    The paper presents results of compressive strength investigations of EN AC-44200 based aluminum alloy composite materials reinforced with aluminum oxide particles at ambient and at temperatures of 100, 200 and 250°C...

  13. Is the Aluminum Hypothesis dead?

    Lidsky, Theodore I


    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust.

  14. ARC welding method for bonding steel with aluminum

    Zhenyang LU; Pengfei HUANG; Wenning GAO; Yan LI; Hanpeng ZHANG; Shuyan YIN


    When welding steel with aluminum, the appearance of intermetallic compounds of Fe and A1 will decrease tenacity and increase rigidity, which leads to bad joint performance. A new type of low energy input (LEI) welding technology is introduced which can be used to weld steel with aluminum. Using the technology, brazing was located on the steel side and arc fusion welding on the aluminum side. The less heat input reduces the thickness of intermetallic compounds to 3-4 μm. Tensile strength tests prove that the joint breaks at the heat-affected zone and the strength is higher than 70% of the aluminum's. Thus, the method can lead to a good performance joint.

  15. Anodizing Aluminum with Frills.

    Doeltz, Anne E.; And Others


    "Anodizing Aluminum" (previously reported in this journal) describes a vivid/relevant laboratory experience for general chemistry students explaining the anodizing of aluminum in sulfuric acid and constrasting it to electroplating. Additions to this procedure and the experiment in which they are used are discussed. Reactions involved are…

  16. Comparative shock response of additively manufactured versus conventionally wrought 304L stainless steel

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.; Palmer, T. A.


    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens that were machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology permits direct fabrication of net- or near-net-shape metal parts. For the present investigation, velocity interferometer (VISAR) diagnostics provided time-resolved measurements of sample response for one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.0 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. The possible contributions of various factors, such as composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and/or sample axis orientation relative to the additive manufacturing deposition trajectory, are considered to explain differences between the AM and baseline 304L dynamic material results.

  17. Comparative Shock Response of Additively Manufactured Versus Conventionally Wrought 304L Stainless Steel*

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.


    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology allows direct fabrication of metal parts. For the present study, a velocity interferometer (VISAR) measured the time-resolved motion of samples subjected to one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.5 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. Observed differences in shock loading and unloading characteristics for the two 304L source variants have been correlated to complementary Kolsky bar results for compressive and tensile testing at lower strain rates. The effects of composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and sample axis orientation relative to the additive manufacturing deposition trajectory have been assessed to explain differences between the AM and baseline 304L dynamic mechanical properties. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  18. Determination of aluminum by four analytical methods

    Hanson, T.J.; Smetana, K.M.


    Four procedures have been developed for determining the aluminum concentration in basic matrices. Atomic Absorption Spectroscopy (AAS) was the routine method of analysis. Citrate was required to complex the aluminum and eliminate matrix effects. AAS was the least accurate of the four methods studied and was adversely affected by high aluminum concentrations. The Fluoride Electrode Method was the most accurate and precise of the four methods. A Gran's Plot determination was used to determine the end point and average standard recovery was 100% +- 2%. The Thermometric Titration Method was the fastest method for determining aluminum and could also determine hydroxide concentration at the same time. Standard recoveries were 100% +- 5%. The pH Electrode Method also measures aluminum and hydroxide content simultaneously, but is less accurate and more time consuming that the thermal titration. Samples were analyzed using all four methods and results were compared to determine the strengths and weaknesses of each. On the basis of these comparisons, conclusions were drawn concerning the application of each method to our laboratory needs.

  19. Opportunities for aluminum-based nanocomposites

    Weiland, H.


    High performance aluminum alloys are conventionally made by heat treating alloys containing a variety of alloying elements in solid solution. Key performance attributes are controlled at the microstructural level by tailoring sizes and morphology of nano-sized second phases. This enabled the successful development of aluminum alloys having properties optimized in strength, damage tolerance and corrosion resistance. However, this process is naturally limited by the solubility of alloying elements in the aluminum matrix. In real world products, significant effort is deployed to achieve a homogeneous distribution of the alloying elements both at the macro and micro scales. Despite these efforts, heat treatable alloys can exhibit chemical gradients at grain boundaries, resulting in sub-optimized properties. Additionally, due to the very nature of the strengthening mechanisms, the properties of heat-treatable alloys are decreasing when exposed to elevated temperatures. To step outside the boundaries given by the solubility of alloying elements in the aluminum matrix, the extrinsic addition of nano-sized particles to the aluminum matrix is being evaluated.

  20. Zinc alloy enhances strength and creep resistance

    Machler, M. [Fisher Gauge Ltd., Peterborough, Ontario (Canada). Fishercast Div.


    A family of high-performance ternary zinc-copper-aluminum alloys has been developed that provides higher strength, hardness, and creep resistance than the traditional zinc-aluminum alloys Zamak 3, Zamak 5, and ZA-8. Designated ACuZinc, mechanical properties comparable to those of more expensive materials make it suitable for high-load applications and those at elevated temperatures. This article describes the alloy`s composition, properties, and historical development.

  1. Investigation of Methods for Selectively Reinforcing Aluminum and Aluminum-Lithium Materials

    Bird, R. Keith; Alexa, Joel A.; Messick, Peter L.; Domack, Marcia S.; Wagner, John A.


    Several studies have indicated that selective reinforcement offers the potential to significantly improve the performance of metallic structures for aerospace applications. Applying high-strength, high-stiffness fibers to the high-stress regions of aluminum-based structures can increase the structural load-carrying capability and inhibit fatigue crack initiation and growth. This paper discusses an investigation into potential methods for applying reinforcing fibers onto the surface of aluminum and aluminum-lithium plate. Commercially-available alumina-fiber reinforced aluminum alloy tapes were used as the reinforcing material. Vacuum hot pressing was used to bond the reinforcing tape to aluminum alloy 2219 and aluminum-lithium alloy 2195 base plates. Static and cyclic three-point bend testing and metallurgical analysis were used to evaluate the enhancement of mechanical performance and the integrity of the bond between the tape and the base plate. The tests demonstrated an increase in specific bending stiffness. In addition, no issues with debonding of the reinforcing tape from the base plate during bend testing were observed. The increase in specific stiffness indicates that selectively-reinforced structures could be designed with the same performance capabilities as a conventional unreinforced structure but with lower mass.

  2. Standard classification of resistance to stress-corrosion cracking of heat-treatable Aluminum alloys

    American Society for Testing and Materials. Philadelphia


    1.1 This classification covers alphabetical ratings of the relative resistance to SCC of various mill product forms of the wrought 2XXX, 6XXX, and 7XXX series heat-treated aluminum alloys and the procedure for determining the ratings. 1.2 The ratings do not apply to metal in which the metallurgical structure has been altered by welding, forming, or other fabrication processes. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  3. Chronic aluminum intake causes Alzheimer's disease: applying Sir Austin Bradford Hill's causality criteria.

    Walton, J R


    Industrialized societies produce many convenience foods with aluminum additives that enhance various food properties and use alum (aluminum sulfate or aluminum potassium sulfate) in water treatment to enable delivery of large volumes of drinking water to millions of urban consumers. The present causality analysis evaluates the extent to which the routine, life-long intake, and metabolism of aluminum compounds can account for Alzheimer's disease (AD), using Austin Bradford Hill's nine epidemiological and experimental causality criteria, including strength of the relationship, consistency, specificity, temporality, dose-dependent response, biological rationale, coherence with existing knowledge, experimental evidence, and analogy. Mechanisms that underlie the risk of low concentrations of aluminum relate to (1) aluminum's absorption rates, allowing the impression that aluminum is safe to ingest and as an additive in food and drinking water treatment, (2) aluminum's slow progressive uptake into the brain over a long prodromal phase, and (3) aluminum's similarity to iron, in terms of ionic size, allows aluminum to use iron-evolved mechanisms to enter the highly-active, iron-dependent cells responsible for memory processing. Aluminum particularly accumulates in these iron-dependent cells to toxic levels, dysregulating iron homeostasis and causing microtubule depletion, eventually producing changes that result in disconnection of neuronal afferents and efferents, loss of function and regional atrophy consistent with MRI findings in AD brains. AD is a human form of chronic aluminum neurotoxicity. The causality analysis demonstrates that chronic aluminum intake causes AD.

  4. Structure and properties of porous ceramics obtained from aluminum hydroxide

    Levkov, R.; Kulkov, Sergey Nikolaevich


    In this paper the study of porous ceramics obtained from aluminum hydroxide with gibbsite modification is presented. The dependence of porosity and mechanical characteristics of the material sintered at different temperatures was studied. It was shown that compressive strength of alumina ceramics increases by 40 times with decreasing the pore volume from 65 to 15%. It was shown that aluminum hydroxide may be used for pore formation and pore volume in the sintered ceramics can be controlled by...

  5. Precipitate-Accommodated Plasma Nitriding for Aluminum Alloys

    Patama Visittipitukul; Tatsuhiko Aizawa; Hideyuki Kuwahara


    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.

  6. Research of Tribological Behaviors of a New Aluminum Bronze

    XU Jian-lin; WANG Zhi-ping; CHEN Chao


    The tribological behaviors were investigated in a new high strength and wear resistant aluminum bronze, with its friction coefficient and wear-rate lower than those of ZQAl9-4 and ZQAl10-4-4 alloys in terms of Chinese national standard.The results showed that different tribological behaviors were attributed material itself. Under boundary lubrication condition, major wear mechanisms of aluminum bronze are adhesive wear and attrition wear. Its wearability depends mainly on material microstructure, shedding hard-particles, rakes and small pits that can store lubricant. The new aluminum bronze may find wide application in high sliding speed, heavy load and boundary lubrication condition.

  7. Effects of Isothermal Aging on Microstructure Evolution, Hardness and Wear Properties of Wrought Co-Cr-Mo Alloy

    Khaimanee, P.; Choungthong, P.; Uthaisangsuk, V.


    In this work, effects of isothermal aging on phase transformation, microstructure evolution, hardness and wear resistance of the wrought Co-Cr-Mo alloy with low carbon content were investigated. Initially, temperature range of FCC to HCP phase transformation of the alloy was determined by a dilatometer test. Then, aging at the temperature of 850 °C for different holding times with subsequent water quenching was carried out. Metallography examination, x-ray diffraction analysis, microhardness test and wear test were performed for Co-Cr-Mo alloy specimens after the isothermal aging. It was found that the FCC to HCP phase transformation occurred in the temperature range between 700 and 970 °C. During the aging treatment, phase fraction of the HCP martensite increased with longer aging time. The FCC to HCP phase transformation was completed after 12 h, because very fine lamellae in different orientations thoroughly dispersed within FCC grains were observed. These lamella structures could be well correlated with formation of the HCP martensite. Small amounts of carbides were found at grain boundaries and grain intersections in the samples aged for 6 and 12 h. In addition, by longer aging time, the average grain size of the aged alloy became a little bit larger, while the hardness noticeably increased. For the examined Co-Cr-Mo alloy, higher amount of the emerged HCP martensitic phase led to the increased hardness value, but reduced friction coefficient and wear rate.

  8. Pitting Corrosion Characterization of Wrought Stellite Alloys in Green Death Solution with Immersion Test and Extreme Value Analysis Model

    Zhang, X. Z.; Liu, R.; Chen, K. Y.; Yao, M. X.


    This article presents a study of the corrosion behavior of two wrought Stellite alloys, Stellite 6B, and Stellite 6K, in Green Death solution, utilizing the extreme value analysis (EVA) model, which is a statistics tool developed based on the Gumbel distribution. Green Death solution a typical oxidized testing solution used in industry for assessing the corrosion resistance of materials. The data of maximum pit depths are obtained from the immersion tests on these alloys for various exposure periods. The top ten maximum pit depths in each specimen surface after the immersion test are measured using a surface texture and contour measuring instrument. These data are the input parameters of the EVA model and the outcomes of the model are the extreme values (minimum thickness) required for the alloys under a given service condition. It is shown that Stellite 6K, which contains higher carbon content but smaller-size carbides, exhibits better corrosion resistance in regard to the extreme value. The results and mechanisms of Stellite 6B and Stellite 6K in Green Death solution corrosion are discussed.

  9. Clinical biochemistry of aluminum

    King, S.W.; Savory, J.; Wills, M.R.


    Aluminum toxicity has been implicated in the pathogenesis of a number of clinical disorders in patients with chronic renal failure on long-term intermittent hemodialysis treatment. The predominant disorders have been those involving either bone (osteomalacic dialysis osteodystrophy) or brain (dialysis encephalopathy). In nonuremic patients, an increased brain aluminum concentration has been implicated as a neurotoxic agent in the pathogenesis of Alzheimer's disease and was associated with experimental neurofibrillary degeneration in animals. The brain aluminum concentrations of patients dying with the syndrome of dialysis encephalopathy (dialysis dementia) are significantly higher than in dialyzed patients without the syndrome and in nondialyzed patients. Two potential sources for the increased tissue content of aluminum in patients on hemodialysis have been proposed: (1) intestinal absorption from aluminum containing phosphate-binding gels, and (2) transfer across the dialysis membrane from aluminum in the water used to prepare the dialysate. These findings, coupled with our everyday exposure to the ubiquitous occurrence of aluminum in nature, have created concerns over the potential toxicity of this metal.

  10. 铸造铝合金镦粗挤压铆接接头失效形式和强度的分析%Analysis on failure modes and strength for upset protrusion riveted joints of casting aluminum alloy

    李渭佳; 杨连发


    Upset protrusion riveting method was used to join castings. The performance of joint obtained by the method upsetting-extrusion was analyzed based on the failure modes and strength. The various testing schemes were obtained through orthogonal test method by chan-ging diameters and depths of the punch. Furthermore, based on the principle of constant volume, rivet heights under different test schemes were calculated, and the upset protrusion riveting tests were carried out. Then, it was conducted the shearing and tensile tests of parts. According to the results, the failure modes were analyzed and the failure limit diagram of joints was obtained. At last, the effects of the geometrical dimensions of the punch on the shear strength and tensile strength of joints were studied. The results show that the tensile strength of joints is lower than the shear strength;joints occur to shearing failure on tail under the shear loading. However, joints occur to head peeling, head shearing and joint pulling failure on tail under the tensile loading.%镦粗挤压铆接是针对铸造件的连接提出的一种铆接技术,从失效形式和强度两个方面对镦粗挤压铆接得到的接头性能进行分析,通过改变冲头直径和深度,采用正交试验,得到不同的试验组合。基于体积不变原理,计算出各个试验组合下需要的铆钉高度,进行镦粗挤压铆接试验,对铆接得到的试件进行剪切和拉伸试验。根据试验结果,分析接头的失效形式,并且绘制出接头的失效极限图,最后分析了冲头尺寸对接头抗剪强度和抗拉强度的影响。研究结果表明:采用镦粗挤压铆接方法得到的接头,其抗剪强度高于抗拉强度;剪切载荷下,接头只发生根部剪断失效;拉伸载荷下,接头发生头部剥离、头部剪断和铆钉根部拉断失效。

  11. Advances in aluminum pretreatment

    Sudour, Michel; Maintier, Philippe [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Simpson, Mark [PPG Industries Inc., 1200 Piedmont Troy, Michigan 48083 (United States); Quaglia, Paolo [PPG Industries Italia, Via Garavelli 21, I-15028 Quattordio (Italy)


    As automotive manufacturers continue to look for ways to reduce vehicle weight, aluminum is finding more utility as a body panel component. The substitution of cold-rolled steel and zinc-coated substrates with aluminum has led to new challenges in vehicle pretreatment. As a result, changes to traditional pretreatment chemistries and operating practices are necessary in order to produce an acceptable coating on aluminum body panels. These changes result in increased sludging and other undesirable characteristics. In addition to the chemistry changes, there are also process-related problems to consider. Many existing automotive pretreatment lines simply were not designed to handle aluminum and its increased demands on filtration and circulation equipment. To retrofit such a system is capital intensive and in addition to requiring a significant amount of downtime, may not be totally effective. Thus, the complexities of pre-treating aluminum body panels have actually had a negative effect on efforts to introduce more aluminum into new vehicle design programs. Recent research into ways of reducing the negative effects has led to a new understanding of the nature of zinc phosphate bath -aluminum interactions. Many of the issues associated with the pretreatment of aluminum have been identified and can be mitigated with only minor changes to the zinc phosphate bath chemistry. The use of low levels of soluble Fe ions, together with free fluoride, has been shown to dramatically improve the efficiency of a zinc phosphate system processing aluminum. Appearance of zinc phosphate coatings, coating weights and sludge are all benefited by this chemistry change. (authors)

  12. Preparation of cast aluminum alloy-mica particle composites

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


    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.

  13. Preparation of cast aluminum alloy-mica particle composites

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


    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.

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


    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...

  15. Microstructures and mechanical properties of Mg–Zn–Zr–Dy wrought magnesium alloys

    Z H Huang; W J Qi; K H Zheng; X M Zhang; M Liu; Z M Yu; J Xu


    Microstructures and phase compositions of as-cast and extruded ZK60–Dy ( = 0–5) alloys were analysed by optical microscope, scanning electron microscope, X-ray diffraction and differential scanning calorimetry. Meanwhile, the tensile mechanical property was tested.With increasing Dy content, Mg–Zn–Dy new phase increases gradually, while MgZn2 phase decreases gradually to disappear. As-cast microstructure is refined gradually; meanwhile extruded one is refined further with decreasing average grain size to 1 m for ZK60–4.32Dy alloy. Second phase, tending to distribute along grain boundary by continuous network in as-cast state, breaks and distributes dispersedly in extrusion state. As-cast tensile mechanical property remains almost unchanged at ambient temperature; however, extruded ones are enhanced significantly at ambient and elevated temperatures, respectively. Tensile strength at 298 and 473 K increases gradually from 355 and 120 MPa for ZK60 alloy to 395 and 171 MPa for ZK60–4.32Dy alloy, respectively. Extruded tensile fractures exhibit a typical character of ductile fracture.

  16. Investigation of electron-beam welding in wrought Inconel 706--experimental and numerical analysis

    Ferro, Paolo [Department of Management and Engineering, University of Padova, Stradella S. Nicola, 3 I-36100 Vicenza (Italy)]. E-mail:; Zambon, Andrea [DIMEG, University of Padova, Via Marzolo, 9 I-35131 Padova (Italy); Bonollo, Franco [Department of Management and Engineering, University of Padova, Stradella S. Nicola, 3 I-36100 Vicenza (Italy)


    Electron-beam welding (EBW) is commonly employed in the aeroengine industry for the welding of high integrity components, fabricated from high-strength superalloys. For such applications, it is important to predict distortions and residual stresses induced by the process. Melt run trials have been carried out on nickel-base superalloy Inconel 706 plates using the EBW technique in order to analyse the effects of welding parameters on geometrical characteristics and microstructure of the bead. Butt-welded plates have been then investigated by means of tensile tests, microstructural analysis, and X-ray diffraction measurements. A finite element model of the process has been set up using an uncoupled thermal-mechanical analysis. The heat source was modelled using a superimposition of a spherical and a conical shape heat source with Gaussian power density distribution in order to reproduce the nail shape of the fusion zone (FZ). The parameters of the source were chosen so that the model would match with experimentally determined weld pool shape and temperatures, measured with thermocouples. Subsequently, the thermal analysis was used to drive the non-linear mechanical analysis. The predicted residual stresses were then compared with X-ray diffraction measurements. It was found that the correct thermal and residual stresses prediction is influenced by the shape of the fusion zone, the highest thermal tensile stress arising under the nailhead of the fusion zone where microfissuring can be observed.

  17. AZ31变形镁合金化学镀前无铬酸洗工艺研究%An Investigation of Chromium-Free Pickling Process for Electroless Nickel Plating on AZ 31 Wrought Magnesium Alloy

    秦铁男; 马立群; 贺忠臣; 姚妍; 丁毅


    主要研究了AZ 31变形镁合金化学镀前的磷酸-硝酸-氢氟酸混合酸洗工艺及各组分对镁合金基体的腐蚀失重表面形貌、镀层与基体的截面形貌和结合力的影响.结果表明:氢氟酸的加入可以有效降低酸洗反应速率并防止新鲜的镁合金基体表面的再次氧化;硝酸的体积分数对镁合金表面形貌的改变有较大影响;当磷酸-硝酸-氢氟酸的体积分数分别为300 mL/L,60 mL/L和100 mL/L时,镀层与基体的结合力最好.%A phosphoric acid-nitric acid-hydrofuoric acid mixed acid pickling process was studied for electroless nickel plating on AZ 31 wrought magnesium alloy sheet. The effects of pickle components on corrosion weight loss, surface morphology, cross section morphology and adhesion strength between the substrate and coating were investigated. The results show that addition of hydrofluoric acid can effectively reduce the rate of pickling reaction and protect the fresh substrate from being Oxidized again. The volume fraction of nitric acid has a great impact on changes of the surface morphology of magnesium substrate. The best adhesion strength between the substrate and the coating is achieved when the pickle solution contains 300 mL/L phosphoric acid, 60 mL/L nitric acid and 100 mL/L hydrofluoric acid.

  18. Experiment research on mechanical behavior of the aluminum laminate in the low-high temperature

    LIN Guo-chang; XIE Zhi-min; WAN Zhi-min; DU Xing-wen


    Aluminum laminate is one kind of the rigidizable composite materials and plays an important role in construction of the inflatable space structure ( ISS), which has potential application in space in the future. But the study of the predecessors mainly focuses on the research of the mechanical behavior in the room temperature,for this reason, mechanical properties of the aluminum laminate in low-high temperature have been studied in this paper. The failure mechanism of the aluminum laminate is also analyzed in the microscopic view by JCXA - T33electron probe. The results show that the temperature has significant influence on the strength and Young's modulus of the aluminum laminate. With the increase of temperature, both the strength and Young's modulus of the aluminum laminate decrease. A model between Young's modulus of the aluminum laminate and temperatures is obtained by using Arrhenius equation. The predicted values by the model agree well with the experiment values.

  19. Effects of Post Weld Heat Treatment on Microstructure and Mechanical Properties of 2A14 High Strength Aluminum Alloy by Electron Beam Welding%焊后热处理对2A14高强铝合金电子束焊接头组织及力学性能的影响

    王亚荣; 黄文荣; 雷华东


    The challenges of significant weight reduction have promoted a focus on selection of light-weight materials. That is the reason that high strength aluminum alloy is becoming widely recognized as the candidates to replace steel. In order to develop proper post weld heat treatment process of 2A14 high strength aluminum alloy welded by electron beam, the effects of post weld heat treatment on microstructure and mechanical properties of 2A14 aluminum alloy welded joint are studied by using optical microscope (OM), scanning electron microscope (SEM), hardness test and tensile test. The results showed that the eutectic structure of the grain-boundary dissolved into the matrix gradually, dispersion-strengthening phase precipitated in weld zone and the hardness of weld seam increased obviously after post weld heat treatment. The tensile strength of the weld seam increased from 3SS Mpa to 465 Mpa, even larger than the base metal. The fracture analysis show the dimples became deeper and the fracture location is all in weld seam, which proposes that the toughness of the weld increased.%轻质化的需求使得人们把关注的焦点集中于轻质材料,高强铝合金作为钢结构材料的最佳替代品,受到越来越广泛的关注,利用电子束焊接高强铝合金,为获得性能优良的2A14高强铝合金电子束焊接接头,采用焊后热处理,通过组织观察(光学显微镜和扫描电镜)、维氏硬度测试、接头拉伸性能测试等方法研究焊后热处理对2A14电子束焊接接头显微组织和性能的影响.结果表明,通过焊后热处理,焊缝中心原晶界分布的网状共晶组织回溶于基体组织中消失,焊缝内部析出大量弥散强化项,基体强化效果增强,显微硬度显著升高,由焊态下低子母材硬度直接升高至超过母材硬度.接头抗拉强度由原来的355MPa提高到465 MPa,超过了母材强度.接头断裂均发生在焊缝,由断口分析发现热处理后接头韧性增强,韧窝深度

  20. Corrosion Inhibitors for Aluminum.

    Muller, Bodo


    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  1. Advances in aluminum anodizing

    Dale, K. H.


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


    Dalrymple, R.S.; Nelson, W.B.


    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  3. Aluminum-tungsten fiber composites with cylindrical geometry and controlled architecture of tungsten reinforcement

    Lucchese, Carl Joesph


    A aluminum matrix-W rod/wire structural material in support of DARPA initiative BAA 08-23 was developed and its density and mechanical strength ascertained, both being part of the DARPA matrices. Aluminum tubes and four 90 degree cross-ply tungsten fiber layers were arranged such that under extreme static pressure conditions the aluminum would viscoplastically flow into the tungsten arrangement to create a metal matrix composite. It was found that a cold isostatic process induced "Brazilian" ...

  4. The Influence of Carbon Nanotube and Roll Bonding Parameters on the Bond Strength of Al Sheets

    Samadzadeh, Mahmoud; Toroghinejad, Mohammad Reza


    This study investigates the bond strength of aluminum sheets subjected to the roll bonding process in the presence of multiwall carbon nanotubes (MWCNTs). The effects of MWCNTs dispersion, thickness reduction, weight fraction of MWCNTs at the interface, and rolling temperature on the bond strength of the commercial pure aluminum sheets are studied. The peeling test is used to evaluate the bond strength of aluminum sheets. Optical microscopy and scanning electron microscopy are also used to evaluate the surface conditions of the peeled surfaces. Results indicate that, compared to the spread method, using the solution dispersion method to disperse MWCNTs reduces aluminum sheet's bond strength. Also, the presence of MWCNTs reduces the sheet's bond strength compared to aluminum sheets at a constant thickness reduction. However, bond strength is increased with higher thickness reductions in the presence or absence of MWCNTs. It is also shown that increasing the entry temperature improves bond strength, but that bond strength enhancement is lower in aluminum-MWCNTs sheets than in aluminum-aluminum sheets.

  5. Inelastic Deformation Analysis of Aluminum Bending Members

    CHENG Ming; SHI Yongjiu; WANG Yuanqing


    Aluminum alloys are typical nonlinear materials, and consequently bending members made of this material exhibit a nonlinear behavior. Most design codes do not pay much attention to such deformations and adopt a simple linear analysis for the calculation of deflections. This paper presents an investigation of the nonlinear deformation of aluminum bending members using the finite-element analysis (FEA). The plastic adaptation coefficient, which can be used to limit the residual deflection, is introduced, and the influence of residual deflection is investigated. A method for evaluating the plastic adoption coefficient is proposed. This paper also shows the load-deflection curve of aluminum bending members and the influence of several parameters. A semi-empirical formula is derived, and some numerical examples are given by FEA. The coefficients of the semi-empirical formula are modified by the FEA results using the nonlinear fitting method. Based on these results, two improved design methods for strength and deformation of aluminum bending members are proposed. Through the comparison with test data, these methods are proved to be suitable for structural design.

  6. Aluminum, parathyroid hormone, and osteomalacia

    Burnatowska-Hledin, M.A.; Kaiser, L.; Mayor, G.H.


    Aluminum exposure in man is unavoidable. The occurrence of dialysis dementia, vitamin D-resistant osteomalacia, and hypochromic microcytic anemia in dialysis patients underscores the potential for aluminum toxicity. Although exposure via dialysate and hyperalimentation leads to significant tissue aluminum accumulation, the ubiquitous occurrence of aluminum and the severe pathology associated with large aluminum burdens suggest that smaller exposures via the gastrointestinal tract and lungs could represent an important, though largely unrecognized, public health problem. It is clear that some aluminum absorption occurs with the ingestion of small amounts of aluminum in the diet and medicines, and even greater aluminum absorption is seen in individuals consuming large amounts of aluminum present in antacids. Aluminum absorption is enhanced in the presence of elevated circulating parathyroid hormone. In addition, elevated PTH leads to the preferential deposition of aluminum in brain and bone. Consequently, PTH is likely to be involved in the pathogenesis of toxicities in those organs. PTH excess also seems to lead to the deposition of aluminum in the parathyroid gland. The in vitro demonstration that aluminum inhibits parathyroid hormone release is consistent with the findings of a euparathyroid state in dialysis patients with aluminum related vitamin D-resistant osteomalacia. Nevertheless, it seems likely that hyperparathyroidism is at least initially involved in the pathogenesis of aluminum neurotoxicity and osteomalacia; the increases in tissue aluminum stores are followed by suppression of parathyroid hormone release, which is required for the evolution of osteomalacia. Impaired renal function is not a prerequisite for increased tissue aluminum burdens, nor for aluminum-related organ toxicity. Consequently, it is likely that these diseases will be observed in populations other than those with chronic renal disease.

  7. Tensile property of Al-Si closed-cell aluminum foam

    YU Hai-jun; YAO Guang-chun; LIU Yi-han


    Al-Si closed-cell aluminum foams of different densities were prepared by molten body transitional foaming process. The tensile behavior of Al-Si closed-cell aluminum foam was studied and the influence of relative densities on the tensile strength and elastic modulus was also researched. The results show that the fracture surfaces of Al-Si closed-cell aluminum foam display quasi-cleavage fiacture consisting of brittle cleavages and ductile dimples. The tensile strength and elastic modulus are strictly affected by the relative density of Al-Si closed-cell aluminum foam. With increasing relative density, the tensile strength increases and the strain at which the peak strength is measured also increases; in addition, the elastic modulus increases with increasing relative density.

  8. Relationship of aluminum to neurocognitive dysfunction in chronic dialysis patients

    Sprague, S.M.; Corwin, H.L.; Tanner, C.M.; Wilson, R.S.; Green, B.J.; Goetz, C.G.


    Aluminum has been proposed as the causative agent in dialysis encephalopathy syndrome. We prospectively assessed whether other, less severe, neuropsychologic abnormalities were also associated with aluminum. A total of 16 patients receiving chronic dialytic therapy were studied. The deferoxamine infusion test (DIT) was used to assess total body aluminum burden. Neurologic function was evaluated by quantitative measures of asterixis, myoclonus, motor strength, and sensation. Cognitive function was assessed by measures of dementia, memory, language, and depression. There were four patients with a positive DIT (greater than 125 micrograms/L increment in serum aluminum) that was associated with an increase in the number of neurologic abnormalities observed, as well as an increase in severity of myoclonus, asterixis, and lower extremity weakness. Patients with a positive DIT also showed significant impairment in memory; however, no differences were noted on tests of dementia, depression, or language. There was no significant correlation between sex, age, presence of diabetes, mode of dialysis, years of chronic renal failure, years of dialysis or years of aluminum ingestion and any neurologic or neurobehavioral measurement, serum aluminum level, or DIT. These changes may represent early aluminum-associated neurologic dysfunction.

  9. Fabrication of aluminum foam from aluminum scrap Hamza

    O. A. Osman1 ,


    Full Text Available In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film.

  10. High-Hot-Strength Ceramic Fibers

    Sayir, Ali; Matson, Lawrence E.


    Continuous fibers consisting of laminae of alumina and yttrium aluminum garnet offer exceptionally high strength, resistance to creep, and chemical stability at high temperatures. These fibers exceed tensile strength of sapphire fibers. Leading candidates for reinforcement of intermetallic-matrix composites in exhaust nozzles of developmental high-speed civil transport aircraft engines. Other applications are in aerospace, automotive, chemical-process, and power-generation industries.

  11. Aluminum matrix composites reinforced with alumina nanoparticles

    Casati, Riccardo


    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  12. Aluminum nanocomposites for elevated temperature applications

    Borgonovo, C.; Apelian, D.; Makhlouf, M. M.


    Aluminum casting alloys conventionally used in the automotive and aerospace industries (i.e., Al-Zn-Mg, and Al-Cu-Mg systems) are able to achieve excellent tensile strength at room temperature. At high temperatures, such alloys lose dimensional stability and their mechanical properties rapidly degrade. Aluminum-based nanocomposites show the potential for enhanced performance at high temperatures. The manufacturing process, however, is difficult; a viable and effective method for large-scale applications has not been developed. In the current study, an innovative and cost-effective approach has been adopted to manufacture Al/AlN composites. A nitrogen-bearing gas is injected into the melt and AlN particles synthesize in-situ via chemical reaction. In a preliminary stage, a model able to predict the amount of reinforcement formed has been developed. AlN dispersoids have been succesfully synthesized in the matrix and the model has been experimentally validated.

  13. Characteristics of aluminum alloy microplastic deformation in different structural states

    Seregin, G.V.; Efimenko, L.L.; Leonov, M.V. [Novosibirsk Pedagogical Inst. (Russian Federation)


    The solution to the problem of improving the mechanical properties (including cyclic strength) of structural materials is largely dependent on our knowledge of the laws governing the development of microplastic deformations in them. The effect of heat and mechanical treatment on the elastoplastic properties and fatigue resistance of the commercial aluminum alloys AK4-1 and D16 is analyzed.

  14. Electroless nickel plating on stainless steels and aluminum


    Procedures for applying an adherent electroless nickel plating on 303 SE, 304, and 17-7 PH stainless steels, and 7075 aluminum alloy was developed. When heat treated, the electroless nickel plating provides a hard surface coating on a high strength, corrosion resistant substrate.

  15. China’s Aluminum Resources


    <正> The aluminum industry makes one of the keyindustries in China’s industrial and agriculturalmodernization and features a high degree ofrelevance with all industries.Of all the 124existing industries in China,113 use aluminum,representing an industrial relevance rate of91%.The consumption of aluminum is also ofhigh relevance with China’s GDP.

  16. Electrically conductive anodized aluminum coatings

    Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)


    A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

  17. Laser-welded Dissimilar Steel-aluminum Seams for Automotive Lightweight Construction

    Schimek, M.; Springer, A.; Kaierle, S.; Kracht, D.; Wesling, V.

    By reducing vehicle weight, a significant increase in fuel efficiency and consequently a reduction in CO 2 emissions can be achieved. Currently a high interest in the production of hybrid weld seams between steel and aluminum exists. Previous methods as laser brazing are possible only by using fluxes and additional materials. Laser welding can be used to join steel and aluminum without the use of additives. With a low penetration depth increases in tensile strength can be achieved. Recent results from laser welded overlap seams show that there is no compromise in strength by decreasing penetration depth in the aluminum.

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

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


    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.

  19. A New Organofunctional Ethoxysilane Self-Assembly Monolayer for Promoting Adhesion of Rubber to Aluminum

    Qian Wang


    Full Text Available Practical adhesion of rubber to aluminum is measured for various aluminum silanization treatments. In this study, 6-(3-triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol (TES was used as the coupling agent for preparing self-assembly monolayers (SAMs on an aluminum surface. The structure and chemical composition of the SAMs were analyzed using Fourier transform infra-red spectroscopy (FT-IR and X-ray photoelectron spectroscopy (XPS. The changes in the surface features of the aluminum surface due to TES treatment were investigated by atomic force microscopy (AFM. The adhesive properties of the silanized aluminum surface and EPDM rubber have been evaluated by a T-peel strength test. The results suggested that the Si-O-Al bonding at aluminum TES interface existed and a TES self-assembly monolayer was formed on the aluminum surface. More than 6.0 KN/m adhesion strength is obtained when the aluminum is silanized with 2.5 mmol/dm3 TES, cured at 160 °C and vulcanized with EPDM rubber at 160 °C for 30 min. It is suggested that the TES self-assembly monolayer is bound to aluminum through its ethoxysilyl functional group, and the thiol function group is strongly crosslinked to EPDM rubber, respectively.

  20. Final Report, Volume 4, The Development of Qualification Standards for Cast Super Duplex Stainless Steel (2507 Wrought Equivalent)

    Hariharan, Vasudevan; Lundin, Carl, W.


    The objective of the program is to determine the suitability of ASTM A923 Standard Test methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic-Ferritic Stainless Steels for 25 Cr Cast Super Duplex Stainless Steels (ASTM A890-5A). Different tests were carried out on the materials procured from various steel foundries as stated in the ASTM A923. The foundries were designated as Foundry A, B, C and D. All the materials were foundry solution annealed. Materials from Foundry D were solution heat treated at The University of Tennessee also and then they were subjected to heat treatment schedule which was derived from the testing of wrought DSS to establish the A923 specification. This was possible because the material from the same heat was sufficient for conducting the full scope of heat treatment. This was done prior to carrying out various other tests. Charpy samples were machined. The Ferrite content was measured in all the Charpy samples using Feritscope® and ASTM E562 Manual Point Count Method. After the ferrite content was measured the samples were sent to AMC-Vulcan, Inc. in Alabama to conduct the Charpy impact test based on ASTM A923 Test Method B. This was followed by etch testing and corrosion analysis based on ASTM A923 Test Methods A and C respectively at University of Tennessee. Hardness testing using Rockwell B and C was also carried out on these samples. A correlation was derived between all the three test methods and the best method for evaluating the presence of intermetallic in the material was determined. The ferrite content was correlated with the toughness values. Microstructural analysis was carried out on the etch test samples using Scanning Electron Microscopy in order to determine if intermetallic phases were present. The fracture surfaces from Charpy test specimens were also observed under SEM in order to determine the presence of any cracks and whether it was a brittle or a ductile fracture. A correlation was

  1. Final Report, Volume 4, The Develpoment of Qualification Standards forCast Super Duplex Stainless Steel (2507 Wrought Equivalent)

    Hariharan, Vasudevan; Lundin, Carl, D.


    The objective of the program is to determine the suitability of ASTM A923 Standard Test methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic-Ferritic Stainless Steels for 25 Cr Cast Super Duplex Stainless Steels (ASTM A890-5A). Different tests were carried out on the materials procured from various steel foundries as stated in the ASTM A923. The foundries were designated as Foundry A, B, C and D. All the materials were foundry solution annealed. Materials from Foundry D were solution heat treated at The University of Tennessee also and then they were subjected to heat treatment schedule which was derived from the testing of wrought DSS to establish the A923 specification. This was possible because the material from the same heat was sufficient for conducting the full scope of heat treatment. This was done prior to carrying out various other tests. Charpy samples were machined. The Ferrite content was measured in all the Charpy samples using Feritscope{reg_sign} and ASTM E562 Manual Point Count Method. After the ferrite content was measured the samples were sent to AMC-Vulcan, Inc. in Alabama to conduct the Charpy impact test based on ASTM A923 Test Method B. This was followed by etch testing and corrosion analysis based on ASTM A923 Test Methods A and C respectively at University of Tennessee. Hardness testing using Rockwell B and C was also carried out on these samples. A correlation was derived between all the three test methods and the best method for evaluating the presence of intermetallic in the material was determined. The ferrite content was correlated with the toughness values. Microstructural analysis was carried out on the etch test samples using Scanning Electron Microscopy in order to determine if intermetallic phases were present. The fracture surfaces from Charpy test specimens were also observed under SEM in order to determine the presence of any cracks and whether it was a brittle or a ductile fracture. A correlation

  2. Final Report, Volume 4, The Develpoment of Qualification Standards forCast Super Duplex Stainless Steel (2507 Wrought Equivalent)

    Hariharan, Vasudevan; Lundin, Carl, D.


    The objective of the program is to determine the suitability of ASTM A923 Standard Test methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic-Ferritic Stainless Steels for 25 Cr Cast Super Duplex Stainless Steels (ASTM A890-5A). Different tests were carried out on the materials procured from various steel foundries as stated in the ASTM A923. The foundries were designated as Foundry A, B, C and D. All the materials were foundry solution annealed. Materials from Foundry D were solution heat treated at The University of Tennessee also and then they were subjected to heat treatment schedule which was derived from the testing of wrought DSS to establish the A923 specification. This was possible because the material from the same heat was sufficient for conducting the full scope of heat treatment. This was done prior to carrying out various other tests. Charpy samples were machined. The Ferrite content was measured in all the Charpy samples using Feritscope{reg_sign} and ASTM E562 Manual Point Count Method. After the ferrite content was measured the samples were sent to AMC-Vulcan, Inc. in Alabama to conduct the Charpy impact test based on ASTM A923 Test Method B. This was followed by etch testing and corrosion analysis based on ASTM A923 Test Methods A and C respectively at University of Tennessee. Hardness testing using Rockwell B and C was also carried out on these samples. A correlation was derived between all the three test methods and the best method for evaluating the presence of intermetallic in the material was determined. The ferrite content was correlated with the toughness values. Microstructural analysis was carried out on the etch test samples using Scanning Electron Microscopy in order to determine if intermetallic phases were present. The fracture surfaces from Charpy test specimens were also observed under SEM in order to determine the presence of any cracks and whether it was a brittle or a ductile fracture. A correlation

  3. Final Report, Volume 4, The Development of Qualification Standards for Cast Super Duplex Stainless Steel (2507 Wrought Equivalent)

    Hariharan, Vasudevan; Lundin, Carl, W.


    The objective of the program is to determine the suitability of ASTM A923 Standard Test methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic-Ferritic Stainless Steels for 25 Cr Cast Super Duplex Stainless Steels (ASTM A890-5A). Different tests were carried out on the materials procured from various steel foundries as stated in the ASTM A923. The foundries were designated as Foundry A, B, C and D. All the materials were foundry solution annealed. Materials from Foundry D were solution heat treated at The University of Tennessee also and then they were subjected to heat treatment schedule which was derived from the testing of wrought DSS to establish the A923 specification. This was possible because the material from the same heat was sufficient for conducting the full scope of heat treatment. This was done prior to carrying out various other tests. Charpy samples were machined. The Ferrite content was measured in all the Charpy samples using Feritscope® and ASTM E562 Manual Point Count Method. After the ferrite content was measured the samples were sent to AMC-Vulcan, Inc. in Alabama to conduct the Charpy impact test based on ASTM A923 Test Method B. This was followed by etch testing and corrosion analysis based on ASTM A923 Test Methods A and C respectively at University of Tennessee. Hardness testing using Rockwell B and C was also carried out on these samples. A correlation was derived between all the three test methods and the best method for evaluating the presence of intermetallic in the material was determined. The ferrite content was correlated with the toughness values. Microstructural analysis was carried out on the etch test samples using Scanning Electron Microscopy in order to determine if intermetallic phases were present. The fracture surfaces from Charpy test specimens were also observed under SEM in order to determine the presence of any cracks and whether it was a brittle or a ductile fracture. A correlation was

  4. Invisible Display in Aluminum

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen


    for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  5. Aluminum for Plasmonics


    in plasmon-enhanced light harvesting,14 photocatalysis ,511 surface- enhanced spectroscopies,1216 optics-based sensing,1722 nonlinear optics,2326...optical response of Al nanoparticles has appeared inconsistent relative to calculated spectra, even forwell-characterized geometries. Some studies have...model- ing their optical response. These results pro- vide a method for estimating the metallic purity of aluminum nanoparticles directly from their

  6. Strength Training

    ... strengthens your heart and lungs. When you strength train with weights, you're using your muscles to ... see there are lots of different ways to train with weights. Try a few good basic routines ...

  7. Strength Training

    ... en español Entrenamiento de la fuerza muscular Strength training is a vital part of a balanced exercise routine that includes aerobic activity and flexibility exercises. Regular aerobic exercise, such as running or ...

  8. Development Of A Novel Discontinuously-Reinforced Aluminum For Space Applications

    Pandey, A. B.; Shah, S.; Shadoan, M.


    Discontinuously-reinforced aluminum (DRA) has been used in aerospace structures such as Ventral Fins and Fan Exit Guide Vanes owing to its superior specific stiffness, specific strength, wear resistance, and thermal resistance as compared to the unreinforced aluminum alloys. In order to reduce engine weight, DRA materials are now being considered for space applications. Higher specific strength at ambient and cryogenic temperatures is one of the main requirements in certain rocket applications. The commercial DRA materials use 6xxx and 2xxx precipitation hardened aluminum alloys as matrices which have limited strengths. Therefore, an aluminum alloy which can provide significantly higher ambient and cryogenic strengths is required. In this paper, a novel aluminum alloy based on Al-Sc-X composition with improved ambient and cryogenic temperature strengthening capability is proposed. In addition, this alloy showed promise for improved strength at elevated temperature. The monolithic alloy and the composite with 15 volume percent SiC and B4C particles were processed using a powder metallurgy approach. The influence of processing parameters on the microstructures and mechanical properties of the monolithic and composite materials is discussed. The alloy showed very high strength and moderate ductility. The influence of hydrogen on the properties of monolithic and composite materials is discussed. The thermal stability of these materials is also evaluated. The strength of the material is discussed in terms of solid solution strengthening, Orowan strengthening, and antiphase boundary strengthening models.

  9. Effects of cell size on compressive properties of aluminum foam

    CAO Xiao-qing; WANG Zhi-hua; MA Hong-wei; ZHAO Long-mao; YANG Gui-tong


    The effects of cell size on the quasi-static and dynamic compressive properties of open cell aluminum foams produced by infiltrating process were studied experimentally. The quasi-static and dynamic compressive tests were carried out on MTS 810 system and SHPB(split Hopkinson pressure bar) respectively. It is found that the elastic moduli and compressive strengths of the studied aluminum foam are not only dependent on the relative density but also dependent on the cell size of the foam under both quasi-static loading and dynamic loading. The foams studied show a significant strain rate sensitivity, the flow strength can be improved as much as 112%, and the cell size also has a sound influence on the strain rate sensitivity of the foams. The foams of middle cell size exhibit the highest elastic modulus, the highest flow strength and the most significant strain rate sensitivity.

  10. Current and Future Uses of Aluminum in the Automotive Industry

    Long, R. S.; Boettcher, E.; Crawford, D.


    Aluminum use is growing in automotive closures and body in white applications to improve vehicle performance and fuel economy. The auto industry is looking for higher-strength aluminum materials needed for strength-driven safety-critical parts. Through cooperation with industrial partners and support from the Department of Energy (DOE), multiple experimental 7xxx alloys were developed for automotive applications. The objective is to enable complex shapes to be formed at temperatures below 225°C. A demonstration part has been developed that is representative of the forming challenges within a current hot-stamped door ring component. This part tooling has been built and installed into a press line which includes blank heating and robotic transfer. Forming trials of these alloys are currently underway and the formability, strength and corrosion performance of these materials are being evaluated.

  11. A damage tolerance comparison of 7075-T6 aluminum alloy and IM7/977-2 carbon/epoxy

    Nettles, Alan T.; Lance, David G.; Hodge, Andrew J.


    A comparison of low velocity impact damage between one of the strongest aluminum alloys, to a new, damage tolerant resin system as a matrix for high strength carbon fibers was examined in this study. The aluminum and composite materials were used as face sheets on a 0.13 g/cu cm aluminum honeycomb. Four levels of impact energy were used; 2.6 J, 5.3 J, 7.8 J and 9.9 J. The beams were compared for static strength and fatique life by use of the four-point bend flexure test. It was found that in the undamaged state the specific strength of the composite face sheets was about twice that of the aluminum face sheets. A sharp drop in strength was observed for the composite specimens impacted at the lowest (2.6J) energy level, but the overall specific strength was still higher than for the aluminum specimens. At all impact energy levels tested, the static specific strength of the composite face sheets were significantly higher than the aluminum face sheets. The fatigue life of the most severely damaged composite specimen was about 17 times greater than the undamaged aluminum specimens when cycled at 1 Hz between 20 percent and 85 percent of ultimate breaking load.

  12. Kinetics of aluminum lithium alloys

    Pletcher, Ben A.


    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

  13. Research of Tribological Behaviors of a New Aluminum Bronze

    XUJian-lin; WANGZhi-ping; CHENChao


    The tribological behaviors were investigated in a new high strength and wear resistant alurninum bronze, with its friction coefficient and wear-rate lower than those of ZQA19-4 and ZQAI10-4-4 alloys in terms of Chinese national standard. The results showed that different tribological behaviors were attributed material itself. Under boundary lubrication condition, major wear mechanisms of aluminum bronze are adhesive wear and attrition wear. Its. wearability depends mainly on material microstructure, shedding hard-particles, rakes and small pits that can store lubricant. The new aluminum bronze may find wide application in high sliding speed, heavy load and boundaty lubrication condition.

  14. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki


    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices.

  15. Aluminum Alloy 7050 Extrusions.


    Artificial Aging Conditions 250 A-l Fatigue Crack Growth Data for C5A Extruded Panel, 7050-T7351X, L-T Orientation, R=0.1 254 A-2 Fatigue...cooldd aluminum and steel bottom blocks (Figure 2) were fabricated for use with this tooling. Metal was melted in a 10,000-lb capacity open- hearth ...time factor, effects of heating through this temperature range to the maximum artificial agirg temperature are additive. The solution of the

  16. Purification of scrap aluminum foil and aluminum melt covering and protecting & atomic purification theory

    倪红军; 孙宝德; 刘满平; 丁文江


    A new flux, JDN-I, including rare earth compounds, for purification of the scraps of 99.99% aluminum foil was introduced. The experimental results indicate that its function of degassing and deoxidizing is excellent. The hydrogen content of the scrap aluminum foil melt purified by JDN-I flux decreases greatly from 4.5 mL/kg to 1.2 mL/kg at 720 ℃. The tensile strength of the samples refined with JDN-I flux increases by 19.2% and the elongation increases by 38.3% in comparison with those without flux. The purification mechanism of JDN-I was discussed and a theory of covering, protecting & atomic purification was also put forward.

  17. Aluminum Carbothermic Technology

    Bruno, Marshall J.


    This report documents the non-proprietary research and development conducted on the Aluminum Carbothermic Technology (ACT) project from contract inception on July 01, 2000 to termination on December 31, 2004. The objectives of the program were to demonstrate the technical and economic feasibility of a new carbothermic process for producing commercial grade aluminum, designated as the ''Advanced Reactor Process'' (ARP). The scope of the program ranged from fundamental research through small scale laboratory experiments (65 kW power input) to larger scale test modules at up to 1600 kW power input. The tasks included work on four components of the process, Stages 1 and 2 of the reactor, vapor recovery and metal alloy decarbonization; development of computer models; and economic analyses of capital and operating costs. Justification for developing a new, carbothermic route to aluminum production is defined by the potential benefits in reduced energy, lower costs and more favorable environmental characteristics than the conventional Hall-Heroult process presently used by the industry. The estimated metrics for these advantages include energy rates at approximately 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-Heroult), capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-Heroult), operating cost reductions of over 10%, and up to 37% reduction in CO2 emissions for fossil-fuel power plants. Realization of these benefits would be critical to sustaining the US aluminum industries position as a global leader in primary aluminum production. One very attractive incentive for ARP is its perceived ability to cost effectively produce metal over a range of smelter sizes, not feasible for Hall-Heroult plants which must be large, 240,000 TPY or more, to be economical. Lower capacity stand alone carbothermic smelters could be utilized to supply molten metal at fabrication facilities similar to the mini-mill concept employed by the steel industry

  18. Extracting aluminum from dross tailings

    Amer, A. M.


    Aluminum dross tailings, an industrial waste, from the Egyptian Aluminium Company (Egyptalum) was used to produce two types of alums: aluminum-sulfate alum [itAl2(SO4)3.12H2O] and ammonium-aluminum alum [ (NH 4)2SO4AL2(SO4)3.24H2O]. This was carried out in two processes. The first process is leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of solute sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purifi ed aluminum dross tailings thus produced. The effects of temperature, time of reaction, and acid concentration on leaching and extraction processes were studied. The product alums were analyzed using x-ray diffraction and thermal analysis techniques.

  19. Laser assisted foaming of aluminum

    Kathuria, Y.P. [Laser X Co. Ltd., Aichi (Japan)


    Recently aluminum foams have evoked considerable interest as an alternative material owing to their wide range of applications ranging from microelectronics, through automobiles to aerospace industries. The manufacturing techniques and characterization methods for aluminum foams require further development to achieve effective and economical use of this material. In this communication the authors demonstrate the feasibility of unidirectional and localized expansion of the aluminum foam using the Nd-YAG/CO{sub 2} laser and powder metallurgy. (orig.)

  20. Ultrasonic Real-Time Quality Monitoring Of Aluminum Spot Weld Process

    Perez Regalado, Waldo Josue

    The real-time ultrasonic spot weld monitoring system, introduced by our research group, has been designed for the unsupervised quality characterization of the spot welding process. It comprises the ultrasonic transducer (probe) built into one of the welding electrodes and an electronics hardware unit which gathers information from the transducer, performs real-time weld quality characterization and communicates with the robot programmable logic controller (PLC). The system has been fully developed for the inspection of spot welds manufactured in steel alloys, and has been mainly applied in the automotive industry. In recent years, a variety of materials have been introduced to the automotive industry. These include high strength steels, magnesium alloys, and aluminum alloys. Aluminum alloys have been of particular interest due to their high strength-to-weight ratio. Resistance spot welding requirements for aluminum vary greatly from those of steel. Additionally, the oxide film formed on the aluminum surface increases the heat generation between the copper electrodes and the aluminum plates leading to accelerated electrode deterioration. Preliminary studies showed that the real-time quality inspection system was not able to monitor spot welds manufactured with aluminum. The extensive experimental research, finite element modelling of the aluminum welding process and finite difference modeling of the acoustic wave propagation through the aluminum spot welds presented in this dissertation, revealed that the thermodynamics and hence the acoustic wave propagation through an aluminum and a steel spot weld differ significantly. For this reason, the hardware requirements and the algorithms developed to determine the welds quality from the ultrasonic data used on steel, no longer apply on aluminum spot welds. After updating the system and designing the required algorithms, parameters such as liquid nugget penetration and nugget diameter were available in the ultrasonic data

  1. Adhesion of oxide layer to metal-doped aluminum hydride surface: Density functional calculations

    Takezawa, Tomoki; Itoi, Junichi; Kannan, Takashi


    The density functional theory (DFT) calculations were carried out to evaluate the adhesion energy of the oxide layer to the metal-doped surface of hydrogen storage material, aluminum hydride (alane, AlH3). The total energy calculations using slab model revealed that the surface doping of some metals to aluminum hydride weakens the adhesion strength of the oxide layer. The influence of titanium, iron, cobalt, and zirconium doping on adhesion strength were evaluated. Except for iron doping, the adhesion strength becomes weak by the doping.

  2. System integration and demonstration of adhesive bonded high temperature aluminum alloys for aerospace structure, phase 2

    Falcone, Anthony; Laakso, John H.


    Adhesive bonding materials and processes were evaluated for assembly of future high-temperature aluminum alloy structural components such as may be used in high-speed civil transport aircraft and space launch vehicles. A number of candidate high-temperature adhesives were selected and screening tests were conducted using single lap shear specimens. The selected adhesives were then used to bond sandwich (titanium core) test specimens, adhesive toughness test specimens, and isothermally aged lap shear specimens. Moderate-to-high lap shear strengths were obtained from bonded high-temperature aluminum and silicon carbide particulate-reinforced (SiC(sub p)) aluminum specimens. Shear strengths typically exceeded 3500 to 4000 lb/in(sup 2) and flatwise tensile strengths exceeded 750 lb/in(sup 2) even at elevated temperatures (300 F) using a bismaleimide adhesive. All faceskin-to-core bonds displayed excellent tear strength. The existing production phosphoric acid anodize surface preparation process developed at Boeing was used, and gave good performance with all of the aluminum and silicon carbide particulate-reinforced aluminum alloys investigated. The results of this program support using bonded assemblies of high-temperature aluminum components in applications where bonding is often used (e.g., secondary structures and tear stoppers).

  3. Effects of silicon, copper and iron on static and dynamic properties of alloy 206 (aluminum-copper) in semi-solids produced by the SEED process

    Lemieux, Alain

    wrought alloy AA6061. At present, there is simply no known application for pressure die-cast alloy with 206 (Liquid Die-casting). This is mainly due to the high propensity to hot cracking and limitations facing the part geometry and the subsequent assembly. This study demonstrated that in addition to pieces produced by semi-solid die-casting using large variations in chemical composition, the SEED process allows obtaining spare sound (sound part) and more complex geometry. Moreover, as the semi-solid parts have less porosity, they can also be machined and welded for some applications. The conclusions of this study demonstrate significant progress in identifying the main issues related to the feasibility of die-casting good parts with high performance using the modified 206 alloy combined with SEED process. This work is therefore a baseline work in the development of new Al-Cu alloys for industries of semi-solid and, at the same time, for the expansion of aluminum for high performance applications in the industry. N.B. This thesis is part of a research project developed by the NSERC / Rio Tinto Akan Industrial Research Chair in Metallurgy of Innovative Aluminum Transformation (CIMTAL).

  4. Structure and properties of porous ceramics obtained from aluminum hydroxide

    Levkov, R.; Kulkov, S.


    In this paper the study of porous ceramics obtained from aluminum hydroxide with gibbsite modification is presented. The dependence of porosity and mechanical characteristics of the material sintered at different temperatures was studied. It was shown that compressive strength of alumina ceramics increases by 40 times with decreasing the pore volume from 65 to 15%. It was shown that aluminum hydroxide may be used for pore formation and pore volume in the sintered ceramics can be controlled by varying the aluminum hydroxide concentration and sintering temperature. Based on these results one can conclude that the obtained structure is very close to inorganic bone matrix and can be used as promising material for bone implants production.

  5. Impact loading of an aluminum/alumina composite

    Johnson, J.N.; Hixson, R.S.; Gray, G.T. III


    The combined demands of increased strength and reduced weight in modern dynamic structural applications require improved understanding of composite materials subject to impact conditions. In order to isolate and identify individual contributions to composite material behavior under these conditions, an experimental and theoretical program was undertaken to examine dynamic behavior of an aluminum/alumina composite consisting of a 6061-T6 aluminum matrix containing elastic, spherical Al{sub 2}O{sub 3} inclusions (10 percent by volume, average diameter {approximately}25 microns). Parallel impact experiments are conducted on these composites and on pure 6061-T6 aluminum samples. This combination provides a direct and immediate qualitative picture of the effect of Al{sub 2}O{sub 3} inclusions the dynamic response of the composite in compression, release, and spallation. Additional experimental information is provided by post-shock reload tests of shock-recovered samples at quasi-static and intermediate strain rates.

  6. Dynamic Property of Aluminum Foam

    S Irie


    Full Text Available Aluminum in the foam of metallic foam is in the early stage of industrialization. It has various beneficial characteristics such as being lightweight, heat resistance, and an electromagnetic radiation shield. Therefore, the use of aluminum foam is expected to reduce the weight of equipment for transportation such as the car, trains, and aircraft. The use as energy absorption material is examined. Moreover aluminum foam can absorb the shock wave, and decrease the shock of the blast. Many researchers have reported about aluminum foam, but only a little information is available for high strain rates (103 s-1 or more. Therefore, the aluminum foam at high strain rates hasn't been not characterized yet. The purpose in this research is to evaluate the behavior of the aluminum form in the high-strain rate. In this paper, the collision test on high strain rate of the aluminum foam is investigated. After experiment, the numerical analysis model will be made. In this experiment, a powder gun was used to generate the high strain rate in aluminum foam. In-situ PVDF gauges were used for measuring pressure and the length of effectiveness that acts on the aluminum foam. The aluminum foam was accelerated to about 400 m/s from deflagration of single component powder and the foam were made to collide with the PVDF gauge. The high strain rate deformation of the aluminum form was measured at two collision speeds. As for the result, pressure was observed to go up rapidly when about 70% was compressed. From this result, it is understood that complete crush of the cell is caused when the relative volume is about 70%. In the next stage, this data will be compared with the numerical analysis.

  7. Neurofibrillary pathology and aluminum in Alzheimer's disease

    Shin, R. W.; Lee, V.M.Y.; Trojanowski, J.Q.


    Since the first reports of aluminum-induced neurofibrillary degeneration in experimental animals, extensive studies have been performed to clarify the role played by aluminum in the pathogenesis of Alzheimer's disease (AD). Additional evidence implicating aluminum in AD includes elevated levels of aluminum in the AD brain, epidemiological data linking aluminum exposure to AD, and interactions between aluminum and protein components in the pathological lesions o...

  8. Porosity and Mechanical Strength of an Autoclaved Clayey Cellular Concrete

    P. O. Guglielmi


    Full Text Available This paper investigates the porosity and the mechanical strength of an Autoclaved Clayey Cellular Concrete (ACCC with the binder produced with 75 wt% kaolinite clay and 25 wt% Portland cement. Aluminum powder was used as foaming agent, from 0.2 wt% to 0.8 wt%, producing specimens with different porosities. The results show that the specimens with higher content of aluminum presented pore coalescence, which can explain the lower porosity of these samples. The porosities obtained with the aluminum contents used in the study were high (approximately 80%, what accounts for the low mechanical strength of the investigated cellular concretes (maximum of 0.62 MPa. Nevertheless, comparing the results obtained in this study to the ones for low temperature clayey aerated concrete with similar compositions, it can be observed that autoclaving is effective for increasing the material mechanical strength.

  9. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi


    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  10. 当量加速腐蚀条件下7 B04-T6高强度铝合金疲劳裂纹扩展规律研究%The fatigue crack growth rule of 7B04-T6 high strength aluminum alloy under equivalently accelerated corrosion environment

    谭晓明; 王海东; 王刚


    Based on an accelerated corrosion testing spectrum complicated for the servicing field environment, the equivalently accelerated corrosion testing of high strength aluminum alloy 7B04-T6 specimens for critical structure were carried out. Corrosion damage under the field environment was successfully simulated and reappeared, and corrosion damage evolvement rule was obtained. By prior⁃corrosion fatigue testing and fractography quantitative analysis, the fatigue crack length (a) and fatigue cycles (N) were gotten, and relationship between fatigue crack growth rate (da/dN) and stress intensify factors rang (ΔK) was analyzed. Moreover the effect of different corrosion damage on fatigue crack growth behavior was quantitatively characterized. The result shows that there is obvious short crack growth behavior during early corrosion stage, the fatigue crack growth rate increases when the corrosion damage is more serious, and the fatigue performance is greatly degraded.%基于编制的机场环境加速试验谱,针对关键结构高强度铝合金件进行当量腐蚀试验,在实验室条件下成功地模拟和再现了服役环境条件的腐蚀损伤,借助复型法观测得到了腐蚀损伤的演化规律;通过预腐蚀疲劳试验和疲劳断口扫描电镜定量分析,得到了裂纹长度a与循环次数N数据集,分析了裂纹扩展速率da/dN与应力强度因子幅值ΔK的对应关系,定量表征了不同程度腐蚀损伤对疲劳裂纹扩展行为的影响规律。结果表明,在腐蚀初期,疲劳裂纹扩展过程中有经典的小裂纹扩展阶段;随着腐蚀损伤的加重,小裂纹行为不明显;腐蚀损伤越严重,疲劳裂纹扩展速率越快,结构抗疲劳性能显著退化。

  11. Effects of Forging and Rolling Process on Microstructure and Mechanical Properties of Wrought Magnesium Alloy AZ31%变形镁合金AZ31锻-轧变形工艺对组织性能的影响

    陈建祥; 刘长瑞; 王庆娟


    对变形镁合金AZ31进行了横向和高向锻造,然后进行轧制,检测了不同锻造比的板坯经轧制后的组织性能变化.结果表明:锻造时,随着锻造比的增大,晶粒组织逐渐细化;当锻造比为1.67时,材料的硬度达到最大值84.4HV,当锻造比为1.82时,材料的硬度为78.9HV;晶粒大小对动态再结晶晶粒尺寸有很大影响,晶粒尺寸较大时,再结晶晶粒尺寸也较大;锻造比为1.82的试样经轧制变形后,可以获得良好的力学性能.其晶粒平均尺寸、抗拉强度和伸长率为分别为3.7μm、281.75 MPa、12.7%.%Wrought magnesium alloy AZ31 were forged going along wide and high. Change of microstructure and mechanical properties with different forging ratio was studied.The results show that the magnesium alloy AZ31 has more fine homogeneous microstructure with forging ratio increasing; The forged specimen when forging ratio is 1.67 has the maximum hardness, 84.4HV. The hardness of the materials decreases when the forging ratio is 1.82, is 78.9 HV; The grain size has a great effect on the dynamic recrystallization grain, with the increasing of grain size, the recrystallization grain size also increasing; the sample with the forging ratio 1.82 by deformation of rolling can obtain good mechanical properties, with average grain size, tensile strength and elongation,3.7μm, 281.75MPa,12.7%.

  12. Effect of Tool Shoulder and Pin Probe Profiles on Friction Stirred Aluminum Welds - a Comparative Study

    H. K. Mohanty; M. M. Mahapatra; P. Kumar; P. Biswas; N. R. Mandal


    In marine application,marine grade steel is generally used for haul and superstructures.However,aluminum has also become a good choice due to its lightweight qualities,while rusting of aluminum is minimal compared to steel.In this paper a study on friction stir welding of aluminum alloys was presented.The present investigation deals with the effects of different friction stir welding tool geometries on mechanical strength and the microstructure properties of aluminum alloy welds.Three distinct tool geometries with different types of shoulder and tool probe profiles were used in the investigation according to the design matrix.The effects of each tool shoulder and probe geometry on the weld was evaluated.It was also observed that the friction stir weld tool geometry has a significant effect on the weldment reinforcement,microhardness,and weld strength.

  13. Ballistic Evaluation of 2060 Aluminum


    experiments in Experimental Facilities (EFs) 108 and 106, as well as John Hogan of ARL/AMB, Hugh Walter of Bowhead Science and Technology, and David aluminum (Al)-based monocoque armored-vehicle hulls such as those of the M2 Bradley Infantry Fighting Vehicles. Also in 2012 the Aluminum

  14. Aluminum Nanoholes for Optical Biosensing

    Carlos Angulo Barrios


    Full Text Available Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (biosensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (biosensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs.

  15. Determining the microstructure and properties of magnesium aluminum composite panels by hot rolling and annealing

    Zilong Zhao


    Full Text Available The researchers made magnesium aluminum composite panels by asymmetric metal packaging and studied rolling temperature, holding time, and high temperature heat treatment, such as short time and low temperatures over long periods of time parameters under the new preparation method. We tested the new magnesium aluminum composite panels' tensing properties and bending performance by using scanning electric mirror and EDS. It is concluded that the new magnesium aluminum composite panels' elongation is 24% under the tensile strength of 260 MPa. Regarding performance when compared with other methods, traditional magnesium aluminum composite panels' elongation is 10%, which shows its advanced nature. At the same time, bending performance test showed that the combination of the composite board has higher performance, offering the reference value for the preparation of magnesium–aluminum composite plate.

  16. Mechanism of removing inclusions from molten aluminum by stirring active molten flux

    周鸣; 李克; 孙宝德; 疏达; 倪红军; 王俊; 张佼


    Removal of inclusions from industrial pure molten aluminum(A01) by stirring active molten flux wasstudied. Wettability of nonmetallic inclusions in the molten aluminum was worse than that in active molten flux. Ac-cording to the surface renewal model, the inclusions were easily transferred into molten active flux from fine alumi-num droplets and then reacted chemically when molten aluminum was dispersed into fine aluminum droplets in stir-ring active molten flux. Tensile tests show that tensile strength of purified tensile sample(as-cast) increases by8.59%. SEM photographs show that the fracture cracks of purified tensile sample are homogeneous, and the dim-ples are small and homogeneous. From metallographs and statistic results of Leco analysis software, it is found thatthe quantities and sizes of the inclusions in purified sample are obviously fewer and smaller than in unpurified tensilesample(as-cast).

  17. Particulate and gaseous emissions when welding aluminum alloys.

    Cole, Homer; Epstein, Seymour; Peace, Jon


    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.

  18. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Tatiana S. Koltsova


    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI:

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

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


    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.

  20. Fast rate fracture of aluminum using high intensity lasers

    Dalton, Douglas Allen

    Laser induced shock experiments were performed to study the dynamics of various solid state material processes, including shock-induced melt, fast rate fracture, and elastic to plastic response. Fast rate fracture and dynamic yielding are greatly influenced by microstructural features such as grain boundaries, impurity particles and alloying atoms. Fast fracture experiments using lasers are aimed at studying how material microstructure affects the tensile fracture characteristics at strain rates above 106 s-1. We used the Z-Beamlet Laser at Sandia National Laboratories to drive shocks via ablation and we measured the maximum tensile stress of aluminum targets with various microstructures. Using a velocity interferometer and sample recovery, we are able to measure the maximum tensile stress and determine the source of fracture initiation in these targets. We have explored the role that grain size, impurity particles and alloying in aluminum play in dynamic yielding and spall fracture at tensile strain rates of ˜3x106 s-1. Preliminary results and analysis indicated that material grain size plays a vital role in the fracture morphology and spall strength results. In a study with single crystal aluminum specimens, velocity measurements and fracture analysis revealed that a smaller amplitude tensile stress was initiated by impurity particles; however, these particles served no purpose in dynamic yielding. An aluminum-magnesium alloy with various grain sizes presented the lowest spall strength, but the greatest dynamic yield strength. Fracture mode in this alloy was initiated by both grain boundaries and impurity particles. With respect to dynamic yielding, alloying elements such as magnesium serve to decrease the onset of plastic response. The fracture stress and yield stress showed no evidence of grain size dependence. Hydrodynamic simulations with material strength models are used to compare with our experiments. In order to study the strain rate dependence of spall

  1. Wettability of Aluminum on Alumina

    Bao, Sarina; Tang, Kai; Kvithyld, Anne; Tangstad, Merete; Engh, Thorvald Abel


    The wettability of molten aluminum on solid alumina substrate has been investigated by the sessile drop technique in a 10-8 bar vacuum or under argon atmosphere in the temperature range from 1273 K to 1673 K (1000 °C to 1400 °C). It is shown that the reduction of oxide skin on molten aluminum is slow under normal pressures even with ultralow oxygen potential, but it is enhanced in high vacuum. To describe the wetting behavior of the Al-Al2O3 system at lower temperatures, a semiempirical calculation was employed. The calculated contact angle at 973 K (700 °C) is approximately 97 deg, which indicates that aluminum does not wet alumina at aluminum casting temperatures. Thus, a priming height is required for aluminum to infiltrate a filter. Wetting in the Al-Al2O3 system increases with temperature.

  2. Hot Extrusion of Aluminum Chips

    Tekkaya, A. Erman; Güley, Volkan; Haase, Matthias; Jäger, Andreas

    The process of hot extrusion is a promising approach for the direct recycling of aluminum machining chips to aluminum profiles. The presented technology is capable of saving energy, as remelting of aluminum chips can be avoided. Depending on the deformation route and process parameters, the chip-based aluminum extradates showed mechanical properties comparable or superior to cast aluminum billets extruded under the same conditions. Using different metal flow schemes utilizing different extrusion dies the mechanical properties of the profiles extruded from chips can be improved. The energy absorption capacity of the profiles the rectangular hollow profiles extruded from chips and as-cast billets were analyzed using the drop hammer test set-up. The formability of the profiles extruded from chips and as-cast material were compared using tube bending tests in a three-roller-bending machine.

  3. Dynamic Mechanical Behaviors of 6082-T6 Aluminum Alloy

    Peng Yibo


    Full Text Available The structural components of high speed trains are usually made of aluminum alloys, for example, 6082. The dynamic mechanical behavior of the material is one of key factors considered in structural design and safety assessment. In this paper, dynamic mechanical experiments were conducted with strain rate ranging from 0.001 s−1 to 100 s−1 using Instron tensile testing machine. The true stress-strain curves were fitted based on experimental data. Johnson-Cook model of 6082-T6 aluminum alloy was built to investigate the effect of strain and strain rate on flow stress. It has shown that the flow stress was sensitive to the strain rate. Yield strength and tensile strength increased with a high strain rate, which showed strain rate effect to some extent. Fracture analysis was carried out by using Backscattered Electron imaging (BSE. As strain rate increased, more precipitates were generated in fracture.

  4. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    Kahl, S; Osikowicz, W


    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strength...

  5. High toughness-high strength iron alloy

    Stephens, J. R.; Witzke, W. R. (Inventor)


    An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

  6. Attitude Strength.

    Howe, Lauren C; Krosnick, Jon A


    Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

  7. Structure formation and properties of a copper-aluminum joint produced by ultrasound-assisted explosive welding

    Kuz'min, E. V.; Peev, A. P.; Kuz'min, S. V.; Lysak, V. I.


    The effect of ultrasound-assisted explosive welding on the structure formation and the properties of copper-aluminum joints is studied. Ultrasound-assisted explosive welding improves the quality of formed copper-aluminum joints, i.e., enhances their strength and significantly reduces the amount of fused metal over the entire weldability range. It is shown that ultrasound-assisted explosive welding can noticeably extend the weldability range of the copper-aluminum pair to obtain equal-in-strength joints with minimum structural heterogeneity in the wide welding range.

  8. Hualu Aluminum Will Construct Large Coal-Power-Aluminum Aluminum Processing Industrial Chain


    The reporter learned from relevant departments of Baiyin City that in order to further push forward industrial upgrading,fulfill expansion and consolidation of the enterprise,Gansu Hualu Aluminum Co.,Ltd(Hualu Aluminum)will implement Out-Of-City-Into-Park project,

  9. Effect of Cerium on Mechanical Performance and Electrical Conductivity of Aluminum Rod for Electrical Purpose


    The effect of rare earth element Ce on mechanical performance and electrical conductivity of aluminum rod for electrical purpose were studied under industrial production condition. Using optical microscope, SEM, TEM, EDS and X-ray diffractometer, the microstructure and phase composition of aluminum rod were measured and analyzed. The results indicate that the content of rare earth element Ce is between 0.05%~0.16% in the aluminum rod for electrical purpose. Its tensile strength is enhanced to some extent. The research also discovers that the tensile strength is enhanced remarkably with impurity element Si content increases. Because influence of Si is big to the conductivity, the Si content should be controlled continuously strictly in the aluminum for electrical purpose. Adding rare earth element Ce reduces the solid solubility of Si in the aluminum matrix, and the negative effect of Si on the aluminum conductor reduces effectively. So the limit of in Si content in aluminum rod for electrical purpose can be relaxed moderately.

  10. Modeling of Sylgard Adhesive Strength

    Stevens, Ralph Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    Sylgard is the name of a silicone elastomeric potting material manufactured by Dow Corning Corporation.1 Although the manufacturer cites its low adhesive strength as a feature of this product, thin layers of Sylgard do in fact have a non-negligible strength, which has been measured in recent tensile and shear debonding tests. The adhesive strength of thin layers of Sylgard potting material can be important in applications in which components having signi cantly di erent thermal expansion properties are potted together, and the potted assembly is subjected to temperature changes. The tensile and shear tractions developed on the potted surfaces of the components can cause signi cant internal stresses, particularly for components made of low-strength materials with a high area-to-volume ratio. This report is organized as follows: recent Sylgard debonding tests are rst brie y summarized, with particular attention to the adhesion between Sylgard and PBX 9501, and also between Sylgard and aluminum. Next, the type of numerical model that will be used to simulate the debonding behavior exhibited in these tests is described. Then the calibration of the debonding model will be illustrated. Finally, the method by which the model parameters are adjusted (scaled) to be applicable to other, non- tested bond thicknesses is summarized, and all parameters of the model (scaled and unscaled) are presented so that other investigators can reproduce all of the simulations described in this report as well as simulations of the application of interest.

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

    C.M. Cheng


    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.

  12. Spray Rolling Aluminum Strip

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.


    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  13. Geochemistry of Aluminum in High Temperature Brines

    Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.


    The objective ofthis research is to provide quantitative data on the equilibrium and thermodynamic properties of aluminum minerals required to model changes in permeability and brine chemistry associated with fluid/rock interactions in the recharge, reservoir, and discharge zones of active geothermal systems. This requires a precise knowledge of the thermodynamics and speciation of aluminum in aqueous brines, spanning the temperature and fluid composition rangesencountered in active systems. The empirical and semi-empirical treatments of the solubility/hydrolysis experimental results on single aluminum mineral phases form the basis for the ultimate investigation of the behavior of complex aluminosilicate minerals. The principal objective in FY 1998 was to complete the solubility measurements on boehmite (AIOOH) inNaC1 media( 1 .O and 5.0 molal ionic strength, IOO-250°C). However, additional measurements were also made on boehmite solubility in pure NaOH solutions in order to bolster the database for fitting in-house isopiestic data on this system. Preliminary kinetic Measurements of the dissolution/precipitation of boehmite was also carried out, although these were also not planned in the earlier objective. The 1999 objectives are to incorporate these treatments into existing codes used by the geothermal industry to predict the chemistry ofthe reservoirs; these calculations will be tested for reliability against our laboratory results and field observations. Moreover, based on the success of the experimental methods developed in this program, we intend to use our unique high temperature pH easurement capabilities to make kinetic and equilibrium studies of pH-dependent aluminosilicate transformation reactions and other pH-dependent heterogeneous reactions.

  14. Investigation of Weibull statistics in fracture analysis of cast aluminum

    Holland, F. A., Jr.; Zaretsky, E. V.


    The fracture strengths of two large batches of A357-T6 cast aluminum coupon specimens were compared by using two-parameter Weibull analysis. The minimum number of these specimens necessary to find the fracture strength of the material was determined. The applicability of three-parameter Weibull analysis was also investigated. A design methodolgy based on the combination of elementary stress analysis and Weibull statistical analysis is advanced and applied to the design of a spherical pressure vessel shell. The results from this design methodology are compared with results from the applicable ASME pressure vessel code.

  15. Investigation of Weibull statistics in fracture analysis of cast aluminum

    Holland, F. A., Jr.; Zaretsky, E. V.


    The fracture strengths of two large batches of A357-T6 cast aluminum coupon specimens were compared by using two-parameter Weibull analysis. The minimum number of these specimens necessary to find the fracture strength of the material was determined. The applicability of three-parameter Weibull analysis was also investigated. A design methodolgy based on the combination of elementary stress analysis and Weibull statistical analysis is advanced and applied to the design of a spherical pressure vessel shell. The results from this design methodology are compared with results from the applicable ASME pressure vessel code.

  16. Subsurface Aluminum Nitride Formation in Iron-Aluminum Alloys

    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. High-temperature discontinuously reinforced aluminum

    Zedalis, M. S.; Bryant, J. D.; Gilman, P. S.; Das, S. K.


    High-temperature discontinuously reinforced aluminum (HTDRA) composites have been developed for elevated-temperature applications by incorporating SiC particulate reinforcement into a rapidly solidified, high-temperature Al-Fe-V-Si (alloy 8009) matrix. HTDRA combines the superior elevated-temperature strength, stability and corrosion resistance of the 8009 matrix with the excellent specific stiffness and abrasion resistance of the discontinuous SiC particulate reinforcement. On a specific stiffness basis, HTDRA is competitive with Ti-6-Al-4V and 17-4 PH stainless steel to temperatures approaching 480°C. Potential aerospace applications being considered for HTDRA include aircraft wing skins, missile bodies, and miscellaneous engine, spacecraft and hypersonic vehicle components.

  18. Effects of as-cast and wrought Cobalt-Chrome-Molybdenum and Titanium-Aluminium-Vanadium alloys on cytokine gene expression and protein secretion in J774A.1 macrophages

    Jakobsen, Stig Storgaard; Larsen, Agnete; Stoltenberg, Meredin


    to the metal implant and wear-products. The aim of the present study was to compare surfaces of as-cast and wrought Cobalt-Chrome-Molybdenum (CoCrMo) alloys and Titanium-Aluminium-Vanadium (TiAlV) alloy when incubated with mouse macrophage J774A.1 cell cultures. Changes in pro- and anti-inflammatory cytokines...... the cell viability. Surface properties of the discs were characterised with a profilometer and with energy dispersive X-ray spectroscopy. We here report, for the first time, that the prosthetic material surface (non-phagocytable) of as-cast high carbon CoCrMo reduces the pro-inflammatory cytokine IL-6...... transcription, the chemokine MCP-1 secretion, and M-CSF secretion by 77%, 36%, and 62%, respectively. Furthermore, we found that reducing surface roughness did not affect this reduction. The results suggest that as-cast CoCrMo alloy is more inert than wrought CoCrMo and wrought TiAlV alloys and could prove...

  19. Development of a Two-Phase Model for the Hot Deformation of Highly-Alloyed Aluminum

    A. J. Beaudoin; J. A. Dantzig; I. M. Robertson; B. E. Gore; S. F. Harnish; H. A. Padilla


    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.

  20. Effects of Thermocapillary Forces during Welding of 316L-Type Wrought, Cast and Powder Metallurgy Austenitic Stainless Steels

    Sgobba, Stefano


    The Large Hadron Collider (LHC) is now under construction at the European Organization for Nuclear Research (CERN). This 27 km long accelerator requires 1248 superconducting dipole magnets operating at 1.9 K. The cold mass of the dipole magnets is closed by a shrinking cylinder with two longitudinal welds and two end covers at both extremities of the cylinder. The end covers, for which fabrication by welding, casting or Powder Metallurgy (PM) was considered, are dished-heads equipped with a number of protruding nozzles for the passage of the different cryogenic lines. Structural materials and welds must retain high strength and toughness at cryogenic temperature. AISI 316L-type austenitic stainless steel grades have been selected because of their mechanical properties, ductility, weldability and stability of the austenitic phase against low-temperature spontaneous martensitic transformation. 316LN is chosen for the fabrication of the end covers, while the interconnection components to be welded on the protrud...

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

    Rajakumar, S.; Balasubramanian, V.


    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.

  2. Effects of compressing and remelting in SIMA processing on semi-solid structure evolution of an Al-Zn wrought alloy

    LIU Changming; ZOU Maohua


    Structure evolution of an Al-Zn wrought alloy in remelting processing in the strain induced melt activated (SIMA)semi-solid procedure was observed, and effects of factors, the remelting temperature, the holding time, and the compression strain, on structures and grain sizes of the alloy were investigated. The results show that (1) the proper temperature of remelting is in the range of 610 to 615℃; (2) the grain size in specimen with greater compression strain is smaller than that with smaller compression strain in condition of the same remelting temperature and holding time, and the grain size in local area with great local equivalent strain is smaller than that with small one; (3) liquid occurs in form of cluster in matrix during remelting and its quantity increases with remelting time increasing; liquid in specimen with great compression strain occurs earlier than that with small one, and quantity of liquid in the center of specimen with greater local equivalent strain is greater than that in the two ends of it; (4) distortion energy after deforming in matrix of the alloy is the significant factor to activate melting of matrix at local area with great local equivalent strain.

  3. Effect on Rare-Earth Element Lanthanum for Bond Strength of Electrodeposited Nickel

    Song Bo; Zhang Xinyu; Jin Lihong; Zhu Yuansong; Mu Tao; Sui Zhitong


    The bond strength of electrodeposited nickel from common electroplate liquid and rare-earth electroplate liquid was tested and contrasted. Electrodeposited nickel of high bond strength was obtained by method of electro-plate nickel with one step and special pretreatment on the surface of aluminum-alloy substrate. The bond strength between the aluminum-alloy substrate and the electrodeposited nickel was tested by the method of heat shock. Then the effect on the bond strength of the electrodeposited nickel from rare-earth compound, the thickness of the electrodeposited nickel,temperature and current density were analyzed. The experimental result shows that the bond strength between the aluminum-alloy substrate and the electrodeposited nickel is 26 MPa under the following condition( current density: 0.2 ~ 0.6 A · dm-2, thickness of the nickel electrodeposition: 8 ~ 15 μm, and temperature of the electroplate liquid: 8 ~ 25 ℃ ).

  4. Invisible Display in Aluminum

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen


    Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish for an integ...... be obtained by shining light from the backside of the workpiece. When there is no light from the backside, the front surface seems totally untouched. This was achieved by laser ablation with ultra-short pulses.......Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish...... for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  5. Anodized aluminum on LDEF

    Golden, Johnny L.


    A compilation of reported analyses and results obtained for anodized aluminum flown on the Long Duration Exposure Facility (LDEF) was prepared. Chromic acid, sulfuric acid, and dyed sulfuric acid anodized surfaces were exposed to the space environment. The vast majority of the anodized surface on LDEF was chromic acid anodize because of its selection as a thermal control coating for use on the spacecraft primary structure, trays, tray clamps, and space end thermal covers. Reports indicate that the chromic acid anodize was stable in solar absorptance and thermal emittance, but that contamination effects caused increases in absorptance on surfaces exposed to low atomic oxygen fluences. There were some discrepancies, however, in that some chromic acid anodized specimens exhibited significant increases in absorptance. Sulfuric acid anodized surfaces also appeared stable, although very little surface area was available for evaluation. One type of dyed sulfuric acid anodize was assessed as an optical baffle coating and was observed to have improved infrared absorptance characteristics with exposure on LDEF.

  6. Effect of TiH2 on preparation of closed-cell aluminum foam and its compressive behavior

    YANG Guo-jun; YU Hai-jun; YAO Guang-chun


    The vesicant problem during the process of preparing closed-cell aluminum foam by molten body transitional foaming process was discussed and the effect of granularity and addition of TiH2 on porosity of closed-cell aluminum foam was investigated.The static compressive behavior of closed-cell aluminum foam and the influence of porosity on static compressive property of closed-cell aluminum foam were researched as well. The results show that with increasing granularity of TiH2, the porosity of closed-cell aluminum foam firstly increases and then decreases gradually, the granularity should be controlled in the range of 38-74 μm which can result in higher porosity. The porosity of closed-cell aluminum foam increases with the increasing addition of TiH2,and the addition of TiH2 should be controlled from 1.5% to 2.5% which can result in homogeneous cell and moderate strength of closed-cell aluminum foam. The compressive process of closed-cell aluminum foam obviously displays linear elastic phase, plastic collapse phase, and densification phase, and the compressive strength grows with decreasing porosity.

  7. Gas evolution behavior of aluminum in mortar

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment


    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs.

  8. Temperature Controlled Laser Joining of Aluminum to Galvanized Steel

    Weller, Daniel; Simon, Jörg; Stritt, Peter; Weber, Rudolf; Graf, Thomas; Bezençon, Cyrille; Bassi, Corrado

    Reliable joining of 6000 series aluminum alloy to galvanized steel is a challenge for current manufacturing technologies. To control and limit the formation of brittle intermetallic phases, mixing of both metals in liquid state has to be avoided. It has been shown that laser weld-brazing is a possible process. Thereby the aluminum and zinc layer of the galvanized steel are molten and the steel remains solid during the process. In addition, to avoid zinc degassing, the aluminum melt bath temperature has to be below zinc boiling temperature of 907°C. To meet these requirements a temperature controlled laser process was developed, allowing to join the two materials without flux and filler material. The thickness of the intermetallic layer shows a dependency on the set temperature used to control the process. At optimum set temperature the thickness of intermetallic phases can be limited to about 5 μm. Tensile strengths of the joints of up to 75% of the aluminum base material were achieved.

  9. Ignition behavior of an aluminum-bonded explosive (ABX)

    Hardin, D. Barrett; Zhou, Min; Horie, Yasuyuki


    We report the results of a study on the ignition behavior of a novel concept and design of a heterogeneous energetic material system called ABX, or aluminum-bonded explosives. The idea is to replace the polymeric binder in polymer-bonded explosives (PBX) with aluminum. The motivation of this study is that a new design may have several desirable attributes, including, among others, electrical conductivity, higher mechanical strength, enhanced integrity, higher energy content, and enhanced thermal stability at elevated temperatures. The analysis carried out concerns the replacement of the Estane binder in a HMX/Estane PBX by aluminum. The HMX volume fraction in the PBX and HMX is approximately 81%. 2D mesoscale simulations are carried out, accounting for elasticity, viscoelasticity, elasto-viscoplasticity, fracture, internal friction, and thermal conduction. Results show that, relative to the PBX, the aluminum bonded explosives (ABX) show significantly less heating and lower ignition sensitivity under the same loading conditions. The findings appear to confirm the expected promise of ABX as a next-generation heterogeneous energetic material system with more desirable attributes.

  10. Aluminum Ion Removal from Monoaluminum Ovotransferrin by Pyrophosphate

    LI,Ying-Qi(李英奇); YANG,Bin-Sheng(杨斌盛)


    The rates at which aluminum was removed from the N- and C-terminal monoaluminum ovotransferrins by pyrophosphate were evaluated by UV difference spectra in 0.01 mol/L Hepes, pH=7.4 and at 37 ℃. Pesudo first-order rate constants as a function of pyrophosphate concentration were measured. The results indicate that the pathways of aluminum removal are different. For the N-terminal binding site, aluminum removal follows simple saturation kinetics, while the removal of aluminum from the C-terminal binding site reverts to the combination of saturation and first-order kinetics. The saturation component is consistent with a rate-limiting conformational change in the protein as has been reported. We propose that the first-order kinetics mechanism is attributed to a pre-equilibrium process. The rate constants of saturation kinetics are accelerated from both terminals with the addition of 0.1 mol/L chloride to the monoaluminum ovotransferrin solutions, whereas the rates of the first-order kinetics are decreased for the C-terminal binding site. The effect of chloride ionic strength causes a continuing increase on kobs for the N- and C-terminal binding sites. Moreover, the kinetics behavior of the N-terminal is more easily affected by chloride than that of the C-terminal. In the experiment presumably the N-terminal site is apparently kinetically more labile than the C-terminal site.

  11. Sensitivity analysis on an AC600 aluminum skin component

    Mendiguren, J.; Agirre, J.; Mugarra, E.; Galdos, L.; Saenz de Argandoña, E.


    New materials are been introduced on the car body in order to reduce weight and fulfil the international CO2 emission regulations. Among them, the application of aluminum alloys is increasing for skin panels. Even if these alloys are beneficial for the car design, the manufacturing of these components become more complex. In this regard, numerical simulations have become a necessary tool for die designers. There are multiple factors affecting the accuracy of these simulations e.g. hardening, anisotropy, lubrication, elastic behavior. Numerous studies have been conducted in the last years on high strength steels component stamping and on developing new anisotropic models for aluminum cup drawings. However, the impact of the correct modelling on the latest aluminums for the manufacturing of skin panels has been not yet analyzed. In this work, first, the new AC600 aluminum alloy of JLR-Novelis is characterized for anisotropy, kinematic hardening, friction coefficient, elastic behavior. Next, a sensitivity analysis is conducted on the simulation of a U channel (with drawbeads). Then, the numerical an experimental results are correlated in terms of springback and failure. Finally, some conclusions are drawn.




    Full Text Available Ecological pressures on chromium have now forced the leather industry to look for possible alternatives. A vegetable- aluminum combination tannage has been studied, with special attention being given to intended final product. Aluminum is mineral tanning agents that are widely used to stabilize collagens in the leather industry. In this study, the crosslinking of vegetable and aluminum, with collagens, have been explored. This kind of chrome free tannage give us leathers with shrinkage temperature around 125oC, elongation at break 65.6%, tensile strength 38 N/mm2, and tear strength 98 N/mm. The chemical properties of the combination tanned leathers are found to be quite normal. Among the combination system evaluated, a vegetable pretannage followed by retannage with basic aluminum sulphate was found to produce stronger leather with the durable characteristics. In contrast, pre-tanning with aluminum possibly tightens the collagen fiber network, preventing high molecular weight vegetable tannins from interacting with collagen fibres. Optimal results were obtained when 10% (w/w vegetable tannins (garad and 2% Aluminum sulphate was used.

  13. Solid-state 27Al nuclear magnetic resonance investigation of three aluminum-centered dyes

    Mroué, Kamal H.


    We report the first solid-state 27Al NMR study of three aluminum phthalocyanine dyes: aluminum phthalocyanine chloride, AlPcCl (1); aluminum-1,8,15,22-tetrakis(phenylthio)-29H,31H-phthalocyanine chloride, AlPc(SPh)4Cl (2); and aluminum-2,3-naphthalocyanine chloride, AlNcCl (3). Each of these compounds contains Al3+ ions coordinating to four nitrogen atoms and a chlorine atom. Solid-state 27Al NMR spectra, including multiple-quantum magic-angle spinning (MQMAS) spectra and quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) spectra of stationary powdered samples have been acquired at multiple high magnetic field strengths (11.7, 14.1, and 21.1 T) to determine their composition and number of aluminum sites, which were analyzed to extract detailed information on the aluminum electric field gradient (EFG) and nuclear magnetic shielding tensors. The quadrupolar parameters for each 27Al site were determined from spectral simulations, with quadrupolar coupling constants (CQ) ranging from 5.40 to 10.0 MHz and asymmetry parameters (η) ranging from 0.10 to 0.50, and compared well with the results of quantum chemical calculations of these tensors. We also report the largest 27Al chemical shielding anisotropy (CSA), with a span of 120 ± 10 ppm, observed directly in a solid material. The combination of MQMAS and computational predictions are used to interpret the presence of multiple aluminum sites in two of the three samples.

  14. Elements inter-diffusion in the turning of wear-resistance aluminum bronze


    Inter-diffusion of elements between the tool and the workpiece during the turning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. The tool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turn a novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion of workpiece materials was found on all tools' surface. The diffusion couples made of tool materials and aluminum bronze were prepared to simulate the inter-diffusion during the machining. The results obtained from tool wear samples were compared with those obtained from diffusion couples. Strong inter-diffusion between the tool materials and the aluminum bronze was observed in all samples. It is concluded that diffusion plays a significant role in the tool wear mechanism.

  15. Temperature dependence of dynamic deformation in FCC metals, aluminum and invar

    Chen, Laura; Swift, D. C.; Austin, R. A.; Florando, J. N.; Hawreliak, J.; Lazicki, A.; Saculla, M. D.; Eakins, D.; Bernier, J. V.; Kumar, M.


    Laser-driven shock experiments were performed on fcc metals, aluminum and invar, at a range of initial temperatures from approximately 120-800 K to explore the effect of initial temperature on dynamic strength properties at strain rates reaching up to 107 s-1. In aluminum, velocimetry data demonstrated an increase of peak stress of the elastic wave, σE, with initial temperature. Alternatively, for invar, σE exhibits little-to-no decrease over the same initial temperature range. Aluminum's unusual deformation behavior is found to primarily be due to anharmonic vibrational effects. Differences in the magnetic structure of aluminum and invar can account for discrepancies in high rate deformation behavior.

  16. Comparison of SCC Thresholds and Environmentally Assisted Cracking in 7050-T7451 Aluminum Plate

    Arnold, Eric M.; Schubbe, Joel J.; Moran, Patrick J.; Bayles, Robert A.


    Aerospace alloys, often aluminums, are frequently exposed to corrosive environments resulting from naval service. These environments may produce significant changes in crack growth characteristics in these materials. An experiment was designed to characterize the effects of environment on crack growth thresholds and fracture characteristics for existing cracks in aluminum 7050-T7451 plate material. This data will be comparatively analyzed against aluminum 7075-T7631, an alloy with known susceptibility to corrosion, in order to determine a relative susceptibility of 7050-T7451, generally considered a superior aluminum alloy in terms of strength and corrosion resistance. The resulting data and subsequent analysis can in turn be used in more accurate determination of aircraft component service life in common corrosive environments experienced by aircraft in naval service.

  17. Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating

    Yang H.S.


    Full Text Available FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.

  18. Scaleable Clean Aluminum Melting Systems

    Han, Q.; Das, S.K. (Secat, Inc.)


    The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.

  19. Tensile properties of SiC/aluminum filamentary composites - Thermal degradation effects

    Skinner, A.; Koczak, M. J.; Lawley, A.


    Aluminium metal matrix composites with a low cost fiber, e.g. SiC, provide for an attractive combination of high elastic modulus and longitudinal strengths coupled with a low density. SiC (volume fraction 0.55)-aluminum (6061) systems have been studied in order to optimize fiber composite strength and processing parameters. A comparison of two SiC/aluminum composites produced by AVCO and DWA is provided. Fiber properties are shown to alter composite tensile properties and fracture morphology. The room temperature tensile strengths appear to be insensitive to thermal exposures at 500 C up to 150 h. The elastic modulus of the composites also appears to be stable up to 400 C, however variations in the loss modulus are apparent. The fracture morphology reflects the quality of the interfacial bond, fiber strengths and fiber processing.

  20. Technical parameters in electromagnetic continuous casting of aluminum alloy

    李玉梅; 张兴国; 贾非; 姚山; 金俊泽


    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. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys


    This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties, The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fine equiaxed grains from coarse columnar grains in the pure aluminum. In comparison with the tradition A356 alloys and wheels, the corresponding microstructure in the testing A356 alloys and wheels was finer. Although the tensile strength was similar between the testing and the tradition A356 alloys and wheels, the ductility of the former (testing) is superior to that of the later (tradition), leading to an excellent combination of strength and ductility from the testing alloys and wheels.

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

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


    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.

  3. The in-situ Ti alloying of aluminum alloys and its application in A356 alloys

    Zongxia LIU


    Full Text Available This research has investigated the in-situ Ti alloying of aluminum alloys and its application to A356 alloys and wheels through the evaluation of microstructure and mechanical properties. The results showed that stable titanium content can be obtained by adding a small quantity of TiO2 into electrolyte of pure aluminum. Under this approach, a greater than 95% absorptivity of titanium was achieved, and the microstructure of the specimens was changed to fineequiaxed grains from coarse columnar grains in the pure aluminum. In comparison with the tradition A356 alloys and wheels, the corresponding microstructure in the testing A356 alloys and wheels was finer. Although the tensile strength was similar between the testing and the tradition A356 alloys and wheels, the ductility of the former (testing is superior to that of the later (tradition, leading to an excellent combination of strength and ductility from the testing alloys and wheels.

  4. Mechanical and microstructural characterization of aluminum reinforced with carbon-coated silver nanoparticles

    Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico)]. E-mail:; Reyes-Gasga, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000 Mexico, D.F. (Mexico); Caudillo, R. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Garcia-Gutierrez, D.I. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States); Marquez-Lucero, A. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Estrada-Guel, I. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Mendoza-Ruiz, D.C. [Centro de Investigacion en Materiales Avanzados (CIMAV), Miguel de Cervantes No. 120, CP 31109, Chihuahua (Mexico); Jose Yacaman, M. [Texas Materials Institute and Chemical Engineering Department, University of Texas at Austin, Austin, TX 78712-1063 (United States)


    Composites of pure aluminum with carbon-coated silver nanoparticles (Ag-C NP) of 10 nm in size were prepared by the mechanical milling process. Transmission electron microscopy showed that the Ag-C NP are homogeneously dispersed into the Al matrix, silver nanoparticles do not coalesce, grow or dissolve in the aluminum matrix due the carbon shell. The values of yield strength ({sigma} {sub y}), maximum strength ({sigma} {sub max}) and micro-hardness Vickers (HVN) of the composites were evaluated and reported as a function of Ag-C NP content. It has been found that the introduction of this type of particles in aluminum strengthen it, increasing all the previous parameters.

  5. Technology and mechanism of a new protein-based core sand for aluminum casting

    石晶玉; 黄天佑; 石红玉; 何镇明


    The protein-based binding material is from natural products, which is nontoxic and recyclable. This kind of green binder is earnestly needed by aluminum casting products. The new protein-based core possesses higher strength and easier shakeout. Its tensile strength is close to that of common resin sands. The micro-mechanism of protein binder was investigated by using infrared spectrum, chemical element analysis, SEM and thermal lost-mass analysis.

  6. Environmental Control over the Primary Aluminum Industry


    <正> To strengthen environmental control over theprimary aluminum industry,the State Environ-mental Protection Administration of China hasrecently issued a notice addressing the follow-ing points:Strengthening environmental control over theexisting primary aluminum companies

  7. Decreasing residual aluminum level in drinking water

    王志红; 崔福义


    The relativity of coagulant dosage, residual turbidity, temperature, pH etc. with residual aluminum concentration were investigated, and several important conclusions were achieved. Firstly, dosage of alum-coagulant or PAC1 influences residual aluminum concentration greatly. There is an optimal-dosage-to-aluminum, a bit less than the optimal-dosage-to-turbidity. Secondly, it proposes that decreasing residual aluminum concentration can be theoretically divided into two methods, either decreasing (even removing) the concentration of particulate aluminum component, or decreasing dissolved aluminum. In these tests there is an optimal value of residual turbidity of postprecipitation at 7.0 NTU. Thirdly, residual aluminum level will increase while water temperature goes higher. At the last, optimal pH value corresponds a minimum dissolved aluminum at a given turbidity. Data shows the optimal pH value decreases with water temperature's increasing.

  8. 21 CFR 172.310 - Aluminum nicotinate.


    ... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be safely... additive, expressed as niacin, shall appear on the label of the food additive container or on that of...

  9. A study on the surface shape and roughness of aluminum alloy for heat exchanger using ball end milling

    Lee, E.; Kim, Y.; jeong, H.; Chung, H.


    Aluminum alloy is a material with a high strength-weight ratio and excellent thermal conductivity. It neither readily corrodes nor quickly weakens at low temperatures, but can be easily recycled. Because of these features, aluminum heat exchangers are widely used in aluminum alloy. In addition, the aluminum alloy used in other areas is expected to gradually increase. As a result, researchers have been continuously studying the cutting patterns of aluminium alloy. However, such studies are fewer than those on the cutting patterns of ordinary steel. Moreover, the research on ball end milling with aluminium alloys has not received much attention. Therefore, in this study, an attempt was made to find the optimal cutting pattern among the seven cutting patterns for the machining of the commonly used aluminum alloy using ball end milling for a heat exchanger. The optimal pattern was found by comparing the different shapes and surface roughness values produced by the seven patterns.

  10. The effect of zinc on the aluminum anode of the aluminum-air battery

    Tang, Yougen; Lu, Lingbin; Roesky, Herbert W.; Wang, Laiwen; Huang, Baiyun

    Aluminum is an ideal material for batteries, due to its excellent electrochemical performance. Herein, the effect of zinc on the aluminum anode of the aluminum-air battery, as an additive for aluminum alloy and electrolytes, has been studied. The results show that zinc can decrease the anodic polarization, restrain the hydrogen evolution and increase the anodic utilization rate.


    Mohammed Ali Hajeeh


    Full Text Available Minimizing the amount of scrap generated in an aluminum extrusion process. An optimizing model is constructed in order to select the best cutting patterns of aluminum logs and billets of various sizes and shapes. The model applied to real data obtained from an existing extrusion factory in Kuwait. Results from using the suggested model provided substantial reductions in the amount of scrap generated. Using sound mathematical approaches contribute significantly in reducing waste and savings when compared to the existing non scientific techniques.

  12. Electrochemical Behavior of Aluminum in Nitric Acid

    CHEN; Hui; ZHU; Li-yang; LIN; Ru-shan; TAN; Hong-bin; HE; Hui


    Aluminum is one of cladding materials for nuclear fuel,it is important to investigate the electrolytic dissolution of aluminum in nitric acid.The electrochemical impedance spectroscopy,polarization curve and cyclic voltammetry cure of anodic aluminum electrode in nitric acid under various conditions were collected(Fig.1).It turns out,under steady state,the thickness of the passivated film of aluminum

  13. Development of third generation advanced high strength steels

    McGrath, Meghan Colleen

    Lightweight duplex steels with combinations of either bainite, acicular ferrite, and austenite or martensite and austenite were investigated as third generation advanced high strength steels targeted for automotive applications. Large additions of manganese (> 13 wt%) and carbon (Strength and ductility were increased while density was decreased with aluminum additions between 2.4 and 5.5 wt% to the steel. This research addressed the dependence of alloying on microstructures and mechanical behavior for high manganese and aluminum duplex steels that were cast and subsequently hot rolled. Duplex steels with different volume fractions of primary delta-ferrite were used to study the crystallography of austenite fanned during the peritectic reaction. Solute profiles across the peritectic interface showed aluminum segregated near the interface which promoted bainitic ferrite formation. Thermal treatments were used to manipulate the concentration and type of oxides and the ferrite plate density was found to correlate with inclusions of low misfit in steels with austenite grain size of 16.5 microm. A steel with bainite and acicular ferrite produced an ultimate tensile strength of 970 MPa and elongation of 40%. The mechanical prope1iies depended on the strengths and size of the microstructural constituents. Work hardening behavior was examined in a steel exhibiting multiple martensitic transformation induced plasticity (gamma-austenite→epsilon-smartensite→alpha-martensite). A strain hardening exponent as high as 1.4 was observed with ultimate tensile strength and elongation as high as 1,165 MPa and 34%.

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

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


    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.

  15. Rapid hardening induced by electric pulse annealing in nanostructured pure aluminum

    Zeng, Wei; Shen, Yao; Zhang, Ning


    Nanostructured pure aluminum was fabricated by heavy cold-rolling and then subjected to recovery annealing either by applying electric pulse annealing or by traditional air furnace annealing. Both annealing treatments resulted in an increase in yield strength due to the occurrence of a “dislocation...

  16. Smaller is Softer : An Inverse Size Effect in a Cast Aluminum Alloy

    Benzerga, A.A.; Hong, S.S.; Kim, K.S.; Needleman, A.; van der Giessen, E.


    The stress–strain curves of A356 cast aluminum alloys exhibit an unusual size effect on flow properties: the finer the microstructure, the lower the tensile flow strength. Tensile tests were carried out on specimens made of an A356 alloy with 7% Si as the main alloying element. The specimens were

  17. Aluminum-titanium hydride-boron carbide composite provides lightweight neutron shield material

    Poindexter, A. M.


    Inexpensive lightweight neutron shield material has high strength and ductility and withstands high internal heat generation rates without excessive thermal stress. This composite material combines structural and thermal properties of aluminum, neutron moderating properties of titanium hydride, and neutron absorbing characteristics of boron carbide.

  18. Smaller is Softer : An Inverse Size Effect in a Cast Aluminum Alloy

    Benzerga, A.A.; Hong, S.S.; Kim, K.S.; Needleman, A.; van der Giessen, E.


    The stress–strain curves of A356 cast aluminum alloys exhibit an unusual size effect on flow properties: the finer the microstructure, the lower the tensile flow strength. Tensile tests were carried out on specimens made of an A356 alloy with 7% Si as the main alloying element. The specimens were ca

  19. Fabrication and refinement of 6061(p)/6063 aluminum laminate by accumulative roll-bonding (ARB) process

    Lee, S.-H.; Saito, Y.; Sakai, T.; Utsunomiya, H.; Tsuji, N. [Osaka Univ. (Japan). Dept. of Materials Sciences and Engineering


    A 6061 aluminum powder compact is fabricated by sheath rolling method using 6063 aluminum tube as a sheath. Accumulative roll-bonding (ARB) process is applied to the powder compact for improvement of its mechanical properties. The ARB process of 8 cycles is performed at ambient temperature under unlubricated conditions without removing the 6063 sheath. The ARB process of 6061 solid aluminum sheet is also performed for comparison to the 6061 powder compact. The tensile strength of the 6061(p)/6063 laminate increases almost linearly with the number of ARB cycles, and reached the maximum of 465MPa at the 6th cycle, which is 2.3 times higher than that of the initial. The elongation drops abruptly at the 1st cycle, and remains at a constant value (about 7%) from the 2nd cycle to the 5th cycle. Both the strength and the elongation decrease with the number of cycles above the 6th cycle. On the other hand, the tensile strength of 6061 sheet increases with the number of cycles gradually. The increase in tensile strength per cycle is greater in the 6061(p)/6063 laminate than that in the ARBed 6061 sheet. This strengthening is probably due to the fine dispersed oxide which was at first oxide film on aluminum. The ultra-fine grains less than 500nm in diameter are developed in the 6061(p)/6063 laminate fabricated by ARB process. (orig.)

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

    Yoshihiko Hangai


    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.

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

    Ray, Ranjan; Jha, Sunil C.


    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. Guangxi Aluminum Giant Made Investment in Changfeng


    <正>A aluminum processing and supporting project (450,000 tons) of Hefei Guangyin Aluminum Company kicked off in Xiatang Town of Changfeng County recently. It is a project jointly invested by Guangxi Investment Group and Guangxi Baise Guangyin Aluminum in Xiatang Town of Changfeng County.

  3. Effects of etching time on enamel bond strengths.

    Triolo, P T; Swift, E J; Mudgil, A; Levine, A


    This study evaluated the effects of etching time on bond strengths of composite to enamel. Proximal surfaces of extracted molars were etched with either a conventional etchant (35% phosphoric acid) or one of two dentin/enamel conditioners, 10% maleic acid (Scotchbond Multi-Purpose Etchant), or a solution of oxalic acid, aluminum nitrate, and glycine (Gluma 1 & 2 Conditioner). Each agent was applied for 15, 30, or 60 seconds. Specimens etched with 35% phosphoric acid had the highest mean bond strengths at each etching time. At the manufacturer's recommended application times, the other two agents gave significantly lower shear bond strengths than phosphoric acid.

  4. Recovering aluminum from aluminum dross in a DC electric-arc rotary furnace

    Tzonev, Tz.; Lucheva, B.


    The recycling of aluminum scrap and dross yields significant economic and energy savings, as well environmental benefits. The recovery of aluminum depends on many factors. The aim of this work is to experimentally investigate aluminum recovery under different conditions. In this study, aluminum dross was processed in a direct-current electric-arc rotary furnace. The presence of crushing refractory bodies during processing was found to increase the degree of aluminum recovery by about ten percent.

  5. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    Lee, Jonathan A.


    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.

  6. Friction Stir Welding of Zr_(55)Al_(10)Ni_5Cu_(30) Bulk Metallic Glass to Crystalline Aluminum

    Zuoxiang Qin; Cuihong Li; Haifeng Zhang; Zhongguang Wang; Zhuangqi Hu; Zhiqiang Liu


    The Zr_(55)Al_(10)Ni_5Cu_(30) bulk metallic glass plate were successfully welded to crystalline aluminum plates by using a friction stir welding (FSW) method. The welded zone was examined. No defects, cracks or pores were observed and no other crystalline phases except for aluminum were found in the welded joint. The strength of the joint is higher than that of aluminum. The glassy phase in the stir zone keeps the amorphous state, showing a successful welding. The storage modulus softens over the glass transition. And the weldability was discussed according to this phenomena.

  7. Effects of AS-cast and wrought cobalt-chrome-molybdenum and titanium-aluminium-vanadium alloys on cytokine gene expression and protein secretion in J774A.1 macrophages

    S S Jakobsen


    Full Text Available Insertion of metal implants is associated with a possible change in the delicate balance between pro- and anti-inflammatory proteins, probably leading to an unfavourable predominantly pro-inflammatory milieu. The most likely cause is an inappropriate activation of macrophages in close relation to the metal implant and wear-products. The aim of the present study was to compare surfaces of as-cast and wrought Cobalt-Chrome-Molybdenum (CoCrMo alloys and Titanium-Aluminium-Vanadium (TiAlV alloy when incubated with mouse macrophage J774A.1 cell cultures. Changes in pro- and anti-inflammatory cytokines [TNF-alpha, IL-6, IL-alpha, IL-1beta, IL-10] and proteins known to induce proliferation [M-CSF], chemotaxis [MCP-1] and osteogenesis [TGF-beta, OPG] were determined by ELISA and Real Time reverse transcriptase - PCR (Real Time rt-PCR. Lactate dehydrogenase (LDH was measured in the medium to asses the cell viability. Surface properties of the discs were characterised with a profilometer and with energy dispersive X-ray spectroscopy. We here report, for the first time, that the prosthetic material surface (non-phagocytable of as-cast high carbon CoCrMo reduces the pro-inflammatory cytokine IL-6 transcription, the chemokine MCP-1 secretion, and M-CSF secretion by 77 %, 36 %, and 62 %, respectively. Furthermore, we found that reducing surface roughness did not affect this reduction. The results suggest that as-cast CoCrMo alloy is more inert than wrought CoCrMo and wrought TiAlV alloys and could prove to be a superior implant material generating less inflammation which might result in less osteolysis.

  8. Laser shocking of 2024 and 7075 aluminum alloys

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


    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.

  9. Luminescent properties of aluminum hydride

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)


    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  10. Aluminum break-point contacts

    Heinemann, Martina; Groot, R.A. de


    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


    Lustman, B.; Losco, E.F.; Cohen, I.


    Nuclear reactor control rods comprised of highly compressed and sintered finely divided metal alloy panticles and fine metal oxide panticles substantially uniformly distributed theretbrough are described. The metal alloy consists essentially of silver, indium, cadmium, tin, and aluminum, the amount of each being present in centain percentages by weight. The oxide particles are metal oxides of the metal alloy composition, the amount of oxygen being present in certain percentages by weight and all the oxygen present being substantially in the form of metal oxide. This control rod is characterized by its high strength and resistance to creep at elevated temperatures.

  12. Aluminum-induced granulomas in a tattoo

    McFadden, N.; Lyberg, T.; Hensten-Pettersen, A.


    A patient who developed localized, granulomatous reactions in a tattoo is described. With the use of scanning electron microscopy and energy dispersive x-ray microanalysis, both aluminum and titanium particles were found in the involved skin sections. Intradermal provocation testing with separate suspensions of aluminum and titanium induced a positive response only in the case of aluminum. Examination by scanning electron microscopy and energy dispersive x-ray microanalysis of the provoked response established aluminum as the only nonorganic element present in the test site tissue. This is the first report of confirmed aluminum-induced, delayed-hypersensitivity granulomas in a tattoo.

  13. Dynamic consolidation of aluminum-silicon carbide composites

    Rabin, B.H.; Korth, G.E.; Williamson, R.L.


    Dynamic consolidation was investigated as a potential method for producing P/M metal matrix composites. In this study, 2124 aluminum powders were mixed with silicon carbide particulate and consolidated using explosives. Numerical simulations were performed to provide insight into the consolidation process and to aid in the selection of experimental conditions. The microstructure of the as-consolidated product was dependent upon processing variables. Careful control of the shock parameters allowed full density, crack free composites to be achieved in cylindrical geometries. Although full density was obtained, low fracture strengths suggested a lack of interparticle bonding, probably resulting from the limited ability to redistribute surface oxides during consolidation. 10 refs., 9 figs.

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

    Archer, Paul; Gupta, Vijay


    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.

  15. Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI) samples

    Savićević, S.; Avdušinović, H.; A. Gigović-Gekić; Z. Jurković; Vukčević, M.; M. Janjić


    Austempered Ductile Iron (ADI) is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In...

  16. Electrodeposition of aluminum on aluminum surface from molten salt

    Wenmao HUANG; Xiangyu XIA; Bin LIU; Yu LIU; Haowei WANG; Naiheng MA


    The surface morphology,microstructure and composition of the aluminum coating of the electrodeposition plates in AlC13-NaC1-KC1 molten salt with a mass ratio of 8:1:1 were investigated by SEM and EDS.The binding force was measured by splat-cooling method and bending method.The results indicate that the coatings with average thicknesses of 12 and 9 μm for both plates treated by simple grinding and phosphating are compacted,continuous and well adhered respectively. Tetramethylammonium chloride (TMAC) can effectively prevent the growth of dendritic crystal,and the anode activation may improve the adhesion of the coating. Binding force analysis shows that both aluminum coatings are strongly adhered to the substrates.

  17. TiN coated aluminum electrodes for DC high voltage electron guns

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A., E-mail: [Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia 23529 and The Applied Research Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Taus, Rhys [Department of Physics, Loyola Marymount University, Los Angeles, California 90045 (United States); Forman, Eric; Poelker, Matthew [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)


    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached −225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ∼22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

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

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


    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.

  19. Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

    Jeom Kee Paik


    Full Text Available The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW, laser welding and friction stir welding (FSW, FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009, jointly funded by its member agencies.

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

    Sornakumar, Thambu; Kathiresan, Marimuthu


    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.

  1. Fractal dimension analysis of aluminum oxide particle for sandblasting dental use.

    Oshida, Y; Munoz, C A; Winkler, M M; Hashem, A; Itoh, M


    Aluminum oxide particles are commonly used as a sandblasting media, particularly in dentistry, for multiple purposes including divesting the casting investment materials and increasing effective surface area for enhancing the mechanical retention strengths of succeedingly applied fired porcelain or luting cements. Usually fine aluminum oxide particles are recycled within the sandblasting machine. Ceramics such as aluminum oxides are brittle, therefore, some portions of recycling aluminum oxide particles might be brittle fractured. If fractured sandblasting particles are involved in the recycling media, it might result in irregularity metallic materials surface as well as the recycling sandblasting media itself be contaminated. Hence, it is necessary from both clinical and practical reasons to monitor the particle conditions in terms of size/shape and effectiveness of sandblasting, so that sandblasting dental prostheses can be fabricated in optimum and acceptable conditions. In the present study, the effect of recycling aluminum oxide particles on the surface texture of metallic materials was evaluated by Fractal Dimension Analysis (FDA). Every week the alumina powder was sampled and analyzed for weight fraction and contaminants. Surface texture of sandblasted standard samples was also characterized by FDA. Results indicate very little change in particle size, while the fractal dimension increased. Fractal dimension analysis showed that the aluminum oxide particle as a sandblasting media should be replaced after 30 or 40 min of total accumulated operation time.

  2. The Role of Surface Preparation Parameters on Cold Roll Bonding of Aluminum Strips

    Jamaati, Roohollah; Toroghinejad, Mohammad Reza


    It is the objective of this article to investigate the influence of surface preparation on the cold roll bonding (CRB) process. In this context, the effects of surface preparation parameters consisting of surface preparation method, surface roughness, scratch-brushing parameters, and the delay time between surface preparation and rolling are investigated on the bond strength of aluminum strips. The bond strength of two adjacent aluminum strips produced by the CRB process is evaluated by the peeling test. Furthermore, the interface region is investigated by metallographic observations. Our findings indicate that higher surface roughness values and shorter delay times improve the bond strength. It is also found that degreasing followed by scratch-brushing yield the best bonding properties.

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

    Cavaliere, P.; Silvello, A.


    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.

  4. Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive

    YUAN Jiang


    Full Text Available Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La.The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.

  5. Isothermal Time-Temperature-Precipitation Diagram for an Aluminum Alloy 6005A by In Situ DSC Experiments

    Benjamin Milkereit


    Full Text Available Time-temperature-precipitation (TTP diagrams deliver important material data, such as temperature and time ranges critical for precipitation during the quenching step of the age hardening procedure. Although the quenching step is continuous, isothermal TTP diagrams are often applied. Together with a so-called Quench Factor Analysis, they can be used to describe very different cooling paths. Typically, these diagrams are constructed based on mechanical properties or microstructures after an interrupted quenching, i.e., ex situ analyses. In recent years, an in situ calorimetric method to record continuous cooling precipitation diagrams of aluminum alloys has been developed to the application level by our group. This method has now been transferred to isothermal experiments, in which the whole heat treatment cycle was performed in a differential scanning calorimeter. The Al-Mg-Si-wrought alloy 6005A was investigated. Solution annealing at 540 °C and overcritical quenching to several temperatures between 450 °C and 250 °C were followed by isothermal soaking. Based on the heat flow curves during isothermal soaking, TTP diagrams were determined. An appropriate evaluation method has been developed. It was found that three different precipitation reactions in characteristic temperature intervals exist. Some of the low temperature reactions are not accessible in continuous cooling experiments and require isothermal studies.

  6. Development of a Precipitation-Strengthened Matrix for Non-quenchable Aluminum Metal Matrix Composites

    Vo, Nhon Q.; Sorensen, Jim; Klier, Eric M.; Sanaty-Zadeh, Amirreza; Bayansan, Davaadorj; Seidman, David N.; Dunand, David C.


    Recent developments in metal matrix composite-encapsulated ceramic armor show promise in lightweight armor technology. The system contains ceramic tiles, such as alumina, sandwiched between unreinforced aluminum or aluminum metal matrix composite (Al-MMC), which has a better toughness compared to the ceramic tiles. The sandwich structures should not be quenched during the fabrication, as the large mismatch in the coefficients of thermal expansion between the ceramic tiles and the unreinforced aluminum or Al-MMC creates internal stresses high enough to fracture the ceramic tiles. However, slow cooling of most commercial alloys creates large precipitates making solute unavailable for the formation of fine precipitates during aging. Here, we develop a non-quenched, high-strength metal matrix utilizing dilute Al-Sc-Zr alloys. We demonstrate that the dilute Al-0.09 Sc-0.045 Zr at.% alloy and the same alloy containing 0-4 vol.% alumina short fibers do not result in precipitation upon slow cooling from a high temperature, and can thereafter be aged to increase their strength. They exhibit a moderate strength, but improved ductility and toughness as compared to common armor aluminum alloys, such as AA5083-H131, making them attractive as armor materials and hybrid armor systems.


    coldhardened by deforming to 83%. It was found that it has low static notch sensitivity (lower than that of heat-treated steels), that static strength raised appreciably by increased cold plastic deformation, and that its fatigue strength is raised substantially by mechanical polishing. (Author)

  8. Surface treatments to improve bond strength in removable partial dentures.

    Kim-Hai, Nguyen; Esquivel-Upshaw, Josephine; Clark, Arthur E


    The metal and resin interface of removable partial dentures is weakened by the poor bond strength between the two materials. This study was designed to test the hypothesis that surface treatments--consisting of air abrasion, with aluminum oxide, tin plating and oxidation, and silanation, either alone or in combination--will improve the bond strength of acrylic resin to metal. Statistical analysis revealed that air abrasion, tin plating/oxidation, and silanation all showed significantly higher bond strength than either abrasion and tin plating, abrasion and silanation, or abrasion alone. Air abrasion demonstrated the greatest effect on improving bond strength. The mean bond strength of samples subjected to a combination of air abrasion, tin plating and oxidation, and silanation was significantly greater than any other combination treatment.

  9. Enhanced adhesion over aluminum solid substrates by controlled atmospheric plasma deposition of amine-rich primers.

    Petersen, Julien; Fouquet, Thierry; Michel, Marc; Toniazzo, Valérie; Dinia, Aziz; Ruch, David; Bomfim, João A S


    Controlled chemical modification of aluminum surface is carried by atmospheric plasma polymerization of allylamine. The amine-rich coatings are characterized and tested for their behavior as adhesion promoter. The adhesion strength of aluminum-epoxy assemblies is shown to increase according to primary amino group content and coating thickness, which in turn can be regulated by plasma power parameters, allowing tailoring the coating chemical properties. The increase in adherence can be correlated to the total and primary amino group contents in the film, indicating covalent bonding of epoxy groups to the primer as the basis of the mechanical improvement.

  10. Microscopic Characteristics of Damage Evolution in Ultrapure Aluminum under Tensile Loading

    QI Mei-Lan; ZHONG Sheng; FAN Duan; LUO Chao; HE Hong-Liang


    A series of plate-experiments are carried out to acquire ultrapure aluminum (purity, 99.999%) samples with damage. Based on the metallographic of all "soft-recovered" samples, the characteristics of damage evolution and spallation damage mechanism in ultrapure aluminum are analyzed in detail. Results show that the damage will increase regularly with increasing loading strength. Most of voids appear in the grain boundary and grow alone under tensile loading before they coalesce each other to form big irregular voids. These analysis results are helpful to understand the evolution process of ductile metal dynamic fracture and establish the damage evolution model.

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

    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


    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.

  12. Effect of Porosity and Cell Size on the Dynamic Compressive Properties of Aluminum Alloy Foams


    The dynamic mechanical properties of open-cell aluminum alloy foams with different relative densities and cell sizeshave been investigated by compressive tests. The strain rates varied from 700 s-1 to 2600 s-1. The experimentalresults showed that the dynamic compressive stress-strain curves exhibited a typical three-stage behavior: elastic,plateau and densification. The dynamic compressive strength of foams is affected not only by the relative densitybut also by the strain rate and cell size. Aluminum alloy foams with higher relative density or smaller cell size aremore sensitive to the strain rate than foams with lower relative density or larger cell size.

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

    Zhao Zhenqing; Wang Chunqing; Du Miao


    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.

  14. Diffusion-bonded beryllium aluminum optical structures

    Grapes, Thomas F.


    Beryllium aluminum material can present significant advantages for optical support structures. A likely advantage of beryllium aluminum compared to aluminum or titanium for such structures is its higher specific stiffness. However, beryllium aluminum material is significantly more expensive than most competing materials. The cost problem with beryllium aluminum is exacerbated if fabrication methods that result in near net shape parts are not used. Near net shape methods result in the least amount of material "thrown away" in the fabrication process. Casting is a primary example of near net shape manufacturing that is appropriate for some optical support structures. Casting aluminum, and other materials as well, is common. Casting of beryllium aluminum is very difficult, however, and has not had significant success. Diffusion bonding - a different approach for achieving near net shape beryllium aluminum optical support structures, was pursued and accomplished. Diffusion bonding is a term used to describe the joining of solid metal pieces under high temperature and pressure, but without melting. Three different optical support structures were designed and built of beryllium aluminum using diffusion bonding. Relatively small solid beryllium aluminum pieces were arranged together and then joined under hot isostatic pressure conditions. The resulting relatively large pressure bonded part was then machined to achieve the final product. Significant cost savings as compared to machining the part from a solid block were realized. Difficulties achieving diffusion bonds in complex joints were experienced and addressed.

  15. Enabling lightweight designs by a new laser based approach for joining aluminum to steel

    Brockmann, Rüdiger; Kaufmann, Sebastian; Kirchhoff, Marc; Candel-Ruiz, Antonio; Müllerschön, Oliver; Havrilla, David


    As sustainability is an essential requirement, lightweight design becomes more and more important, especially for mobility. Reduced weight ensures more efficient vehicles and enables better environmental impact. Besides the design, new materials and material combinations are one major trend to achieve the required weight savings. The use of Carbon Fiber Reinforced Plastics (abbr. CFRP) is widely discussed, but so far high volume applications are rarely to be found. This is mainly due to the fact that parts made of CFRP are much more expensive than conventional parts. Furthermore, the proper technologies for high volume production are not yet ready. Another material with a large potential for lightweight design is aluminum. In comparison to CFRP, aluminum alloys are generally more affordable. As aluminum is a metallic material, production technologies for high volume standard cutting or joining applications are already developed. In addition, bending and deep-drawing can be applied. In automotive engineering, hybrid structures such as combining high-strength steels with lightweight aluminum alloys retain significant weight reduction but also have an advantage over monolithic aluminum - enhanced behavior in case of crash. Therefore, since the use of steel for applications requiring high mechanical properties is unavoidable, methods for joining aluminum with steel parts have to be further developed. Former studies showed that the use of a laser beam can be a possibility to join aluminum to steel parts. In this sense, the laser welding process represents a major challenge, since both materials have different thermal expansion coefficients and properties related to the behavior in corrosive media. Additionally, brittle intermetallic phases are formed during welding. A promising approach to welding aluminum to steel is based on the use of Laser Metal Deposition (abbr. LMD) with deposit materials in the form of powders. Within the present work, the advantages of this

  16. Electrically Conductive Anodized Aluminum Surfaces

    Nguyen, Trung Hung


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

  17. Aluminum/air electrochemical cells

    Wang, Lei; 王雷


    Aluminum (Al) is a very promising energy carrier given its high capacity and energy density, low cost, earth abundance and environmental benignity. The Al/air battery as a kind of metal/air electrochemical cell attracts tremendous attention. Traditional Al/air batteries suffer from the self-corrosion and related safety problems. In this work, three new approaches were investigated to tackle these challenges and to develop high-performance Al/air cells: (1) incorporate an additional hydrogen/a...

  18. Aluminum Honeycomb Characteristics in Dynamic Crush Environments

    Bateman, Vesta I.; Swanson, Lloyd H.


    Fifteen aluminum honeycomb cubes (3 in.) have been crushed in the Mechanical Shock Laboratory's drop table testing machines. This report summarizes shock experiments with honeycomb densities of 22.1 pcf and 38.0 pcf and with crush weights of 45 lb, 168 lb, and 268 lb. The honeycomb samples were crushed in all three orientations, W, L, and T. Most of the experiments were conducted at an impact velocity of {approx}40 fps, but higher velocities of up to 90 fps were used for selected experiments. Where possible, multiple experiments were conducted for a specific orientation and density of the honeycomb samples. All results are for Hexcel honeycomb except for one experiment with Alcore honeycomb and have been evaluated for validity. This report contains the raw acceleration data measured on the top of the drop table carriage, pictures of the crushed samples, and normalized force-displacement curves for all fifteen experiments. These data are not strictly valid for material characteristics in L and T orientations because the cross-sectional area of the honeycomb changed (split) during the crush. However, these are the best data available at this time. These dynamic crush data do suggest a significant increase in crush strength to 8000 psi ({approximately} 25-30% increase) over quasi-static values of {approximately}6000 psi for the 38.0 pcf Hexcel Honeycomb in the T-orientation. An uncertainty analysis is included and estimates the error in these data.

  19. Purification technology of molten aluminum

    孙宝德; 丁文江; 疏达; 周尧和


    Various purification methods were explored to eliminate the dissolved hydrogen and nonmetallic inclusions from molten aluminum alloys. A novel rotating impeller head with self-oscillation nozzles or an electromagnetic valve in the gas circuit was used to produce pulse gas currents for the rotary impeller degassing method. Water simulation results show that the size of gas bubbles can be decreased by 10%-20% as compared with the constant gas current mode. By coating ceramic filters or particles with active flux or enamels, composite filters were used to filter the scrap A356 alloy and pure aluminum. Experimental results demonstrate that better filtration efficiency and operation performance can be obtained. Based on numerical calculations, the separation efficiency of inclusions by high frequency magnetic field can be significantly improved by using a hollow cylinder-like separator or utilizing the effects of secondary flow of the melt in a square separator. A multi-stage and multi-media purification platform based on these methods was designed and applied in on-line processing of molten aluminum alloys. Mechanical properties of the processed scrap A356 alloy are greatly improved by the composite purification.

  20. Microbial corrosion of aluminum alloy.

    Yang, S S; Chen, C Y; Wei, C B; Lin, Y T


    Several microbes were isolated from the contaminated fuel-oil in Taiwan and the microbial corrosion of aluminum alloy A356-T6 was tested by MIL-STD-810E test method. Penicillium sp. AM-F5 and Cladosporium resinac ATCC 22712 had significant adsorption and pitting on the surface of aluminum alloy, Pseudomonas acruginosa AM-B5 had weak adsorption and some precipitation in the bottom, and Candida sp. AM-Y1 had the less adsorption and few cavities formation on the surface. pH of the aqueous phase decreased 0.3 to 0.7 unit for 4 months of incubation. The corrosion of aluminum alloy was very significant in the cultures of Penicillium sp. AM-F2, Penicillium sp. AM-F5 and C. resinac ATCC 22712. The major metabolites in the aqueous phase with the inoculation of C. resinac were citric acid and oxalic acid, while succinic acid and fumaric acid were the minors.

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


    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.


    Upadhyay, Piyush; Hovanski, Yuri; Fifield, Leonard S.; Simmons, Kevin L.


    Friction Stir Scribe (FSS) technology is a relatively new variant of Friction Stir Welding (FSW) which enables lap joining of dissimilar material with very different melting points and different high temperature flow behaviors. The cutter scribe attached at the tip of FSW tool pin effectively cuts the high melting point material such that a mechanically interlocking feature is created between the dissimilar materials. The geometric shape of this interlocking feature determines the shear strength attained by the lap joint. This work presents first use of scribe technology in joining polymers to aluminum alloy. Details of the several runs of scribe welding performed in lap joining of ~3.175mm thick polymers including HDPE, filled and unfilled Nylon 66 to 2mm thick AA5182 are presented. The effect of scribe geometry and length on weld interlocking features is presented along with lap shear strength evaluations.

  3. Composite coatings of titanium-aluminum nitride for steel against corrosion induced by solid NaCl deposit and water vapor at 600 °C

    M.S. Li


    Full Text Available Composite coatings (Ti,AlN with different Al content were deposited on a wrought martensite steel 1Cr11Ni2W2MoV by reactive multi-arc ion plating. With the addition of Al to the coatings, the crystallographic structure of them changed from B1 NaCl to B4 ZnS, the relevant hardness and adhesive strength firstly increased then decreased and their oxidation-resistance was also dramatically improved. It was indicated that the introduction of Al was beneficial to (Ti,AlN coatings against corrosion induced by NaCl(s in wet oxygen at 600 °C as well as wet corrosion in NaCl solution at ambient temperature.

  4. Optical Transmittance of Anodically Oxidized Aluminum Alloy

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


    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.

  5. [Link between aluminum neurotoxicity and neurodegenerative disorders].

    Kawahara, Masahiro


    Aluminum is an old element that has been known for a long time, but some of its properties are only now being discovered. Although environmentally abundant, aluminum is not essential for life; in fact, because of its specific chemical properties, aluminum inhibits more than 200 biologically important functions and exerts various adverse effects in plants, animals, and humans. Aluminum is a widely recognized neurotoxin. It has been suggested that there is a relationship between exposure to aluminum and neurodegenerative diseases, including dialysis encephalopathy, amyotrophic lateral sclerosis and parkinsonism dementia in the Kii Peninsula and Guam, as well as Alzheimer' s disease: however, this claim remains to be verified. In this chapter, we review the detailed characteristics of aluminum neurotoxicity and the link between Alzheimer' s disease and other neurodegenerative diseases, based on recent findings on metal-metal interactions and the functions of metalloproteins in synapses.


    Josip Peko


    Full Text Available This study examined steel and aluminum variants of modern exhibition structures in which the main design requirements include low weight (increased span/depth ratio, transportation, and construction and durability (resistance to corrosion. This included a design situation in which the structural application of aluminum alloys provided an extremely convenient and practical solution. Viability of an aluminum structure depends on several factors and requires a detailed analysis. The overall conclusion of the study indicated that aluminum can be used as a structural material and as a viable alternative to steel for Croatian snow and wind load values and evidently in cases in which positive properties of aluminum are required for structural design. Furthermore, a structural fire analysis was conducted for an aluminum variant structure by using a zone model for realistic fire analysis. The results suggested that passive fire protection for the main structural members was not required in the event of areal fire with duration of 60 min.

  7. In Situ Synthesis Aluminum Borate Whiskers Reinforced TiB2 Matrix Composites for Application in Aluminum Reduction Cells

    Zhang, Gang; Yang, Jianhong


    The TiB2 matrix ceramics reinforced by aluminum borate whiskers (Al18B4O33 w) had been prepared by the pressureless sintering method. The mechanical properties and densification behavior of the TiB2 matrix ceramics were investigated. The results showed that Al18B4O33 w was in situ synthesized by the reaction of boehmite (AlOOH) and TiB2 powders during the sintering process. Increasing the sintering temperature had benefited for densification of the TiB2 matrix ceramics. Al18B4O33 w could increase the flexural strength and Vicker's hardness. It is obtained that the maximum value Vicker's hardness with 1.81 GPa and flexural strength with 82 MPa for samples sintered at 1600°C.

  8. Investigations on mechanical properties of aluminum hybrid composites

    Dora Siva Prasad


    Full Text Available A double stir casting process was used to fabricate aluminum composites reinforced with various volume fractions of 2, 4, 6, and 8 wt% RHA and SiC particulates in equal proportions. Properties such as hardness, density, porosity and mechanical behavior of the unreinforced and Al/x%RHA/x%SiC (x = 2, 4, 6, and 8 wt% reinforced hybrid composites were examined. Scanning electron microscope (model JSM-6610LV was used to study the microstructural characterization of the composites. It was observed that the hardness and porosity of the hybrid composite increased with increasing reinforcement volume fraction and density decreased with increasing particle content. It was also observed that the UTS and yield strength increase with an increase in the percent weight fraction of the reinforcement particles, whereas elongation decreases with the increase in reinforcement. The increase in strength of the hybrid composites is probably due to the increase in dislocation density. A systematic study of the base alloy and composites was done using the Brinell hardness measurement and the corresponding age hardening curves were obtained. It was observed that in comparison to that of the base aluminum alloy, the precipitation kinetics of the composites were accelerated by adding the reinforcement. This effectively reduced the time for obtaining the maximum hardness by the aging heat treatment.

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

    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

  10. Structure of Liquid Aluminum and Hydrogen Absorption

    LIU Yang; DAI Yongbing; WANG Jun; SHU Da; SUN Baode


    The hydrogen content in aluminum melts at different temperature was detected. The structure in aluminum melts was investigated by molecular dynamics simulation. The first peak position of pair correlation function, atomic coordination number and viscosity of aluminum melts were calculated and they changed abnormally in the same temperature range. The mechanism of hydrogen absorption has been discussed. From molecular dynamics calculations, the interdependence between melt structural properties and hydrogen absorption were obtained.

  11. Prospecting sugarcane genes involved in aluminum tolerance.

    Drummond Rodrigo D.; Guimarães Claudia T.; Felix Juliana; Ninamango-Cárdenas Fernando E.; Carneiro Newton P.; Paiva Edilson; Menossi Marcelo


    Aluminum is one of the major factors that affect plant development in acid soils, causing a substantial reduction in yield in many crops. In South America, about 66% of the land surface is made up of acid soils where high aluminum saturation is one of the main limiting factors for agriculture. The biochemical and molecular basis of aluminum tolerance in plants is far from being completely understood despite a growing number of studies, and in the specific case of sugarcane there are virtually...

  12. Strength and Balance Exercises

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Strength and Balance Exercises Updated:Sep 8,2016 If ... Be Safe While Being Active - Stretching & Flexibility Exercises - Strength & Balance Exercises - Problems & Solutions for Being Active - FAQs ...

  13. Aluminum-stabilized NB3SN superconductor

    Scanlan, Ronald M.


    An aluminum-stabilized Nb.sub.3 Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb.sub.3 Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials.

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

    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

  15. 3D printing of high-strength aluminium alloys.

    Martin, John H; Yahata, Brennan D; Hundley, Jacob M; Mayer, Justin A; Schaedler, Tobias A; Pollock, Tresa M


    Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel

  16. The Aluminum Deep Processing Project of North United Aluminum Landed in Qijiang


    <正>On April 10,North United Aluminum Company respectively signed investment cooperation agreements with Qijiang Industrial Park and Qineng Electricity&Aluminum Co.,Ltd,signifying the landing of North United Aluminum’s aluminum deep processing project in Qijiang.

  17. Silicon reduces aluminum accumulation in rats: relevance to the aluminum hypothesis of Alzheimer disease.

    Bellés, M; Sánchez, D J; Gómez, M; Corbella, J; Domingo, J L


    In recent years, a possible relation between the aluminum and silicon levels in drinking water and the risk of Alzheimer disease (AD) has been established. It has been suggested that silicon may have a protective effect in limiting oral aluminum absorption. The present study was undertaken to examine the influence of supplementing silicon in the diet to prevent tissue aluminum retention in rats exposed to oral aluminum. Three groups of adult male rats were given by gavage 450 mg/kg/day of aluminum nitrate nonahydrate 5 days a week for 5 weeks. Concurrently, animals received silicon in the drinking water at 0 (positive control), 59, and 118 mg Si/L. A fourth group (-Al, - Si) was designated as a negative control group. At the end of the period of aluminum and silicon administration, urines were collected for 4 consecutive days, and the urinary aluminum levels were determined. The aluminum concentrations in the brain (various regions), liver, bone, spleen, and kidney were also measured. For all tissues, aluminum levels were significantly lower in the groups exposed to 59 and 118 mg Si/L than in the positive control group; significant reductions in the urinary aluminum levels of the same groups were also found. The current results corroborate that silicon effectively prevents gastrointestinal aluminum absorption, which may be of concern in protecting against the neurotoxic effects of aluminum.

  18. Strength Training for Girls.

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda


    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

  19. Strength Training for Girls.

    Connaughton, Daniel; Connaughton, Angela; Poor, Linda


    Strength training can be fun, safe, and appropriate for young girls and women and is an important component of any fitness program when combined with appropriate cardiovascular and flexibility activities. Concerns and misconceptions regarding girls' strength training are discussed, presenting general principles of strength training for children…

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

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


    . The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA......2024 and AA7075) are investigated for the resistance spot welding of AA1050 aluminum sheets of three different thicknesses. Microstructural and mechanical analysis demonstrates that significant improvement in weld bead morphology and strength are obtained with the addition of metal powder...

  1. High-power Laser Welding of Thick Steel-aluminum Dissimilar Joints

    Lahdo, Rabi; Springer, André; Pfeifer, Ronny; Kaierle, Stefan; Overmeyer, Ludger

    According to the Intergovernmental Panel on Climate Change (IPCC), a worldwide reduction of CO2-emissions is indispensable to avoid global warming. Besides the automotive sector, lightweight construction is also of high interest for the maritime industry in order to minimize CO2-emissions. Using aluminum, the weight of ships can be reduced, ensuring lower fuel consumption. Therefore, hybrid joints of steel and aluminum are of great interest to the maritime industry. In order to provide an efficient lap joining process, high-power laser welding of thick steel plates (S355, t = 5 mm) and aluminum plates (EN AW-6082, t = 8 mm) is investigated. As the weld seam quality greatly depends on the amount of intermetallic phases within the joint, optimized process parameters and control are crucial. Using high-power laser welding, a tensile strength of 10 kN was achieved. Based on metallographic analysis, hardness tests, and tensile tests the potential of this joining method is presented.

  2. Application of Image Processing to Predict Compressive Behavior of Aluminum Foam

    Kim Sanghoon


    Full Text Available An image processing technique was used to model the internal structure of aluminum foam in finite element analysis in order to predict the compressive behavior of the material. Finite element analysis and experimental tests were performed on aluminum foam with densities of 0.2, 0.25, and 0.3 g/cm3. It was found that although the compressive strength predicted from the finite element analysis was higher than that determined experimentally, the predicted compressive stress-strain curves exhibited a tendency similar to those determined from experiments for both densities. However, the behavior of the predicted compressive stress-strain curves was different from the experimental one as the applied strain increased. The difference between predicted and experimental stress-strain curves in a high strain range was due to contact between broken aluminum foam walls by the large deformation.

  3. Tool wear mechanism in turning of novel wear-resisting aluminum bronze

    倪东惠; 夏伟; 张大童; 郭国文; 邵明


    Tool wear and wear mechanism during the turning of a wear-resisting aluminum bronze have been stud-ied. Tool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turn a novelhigh strength, wear resisting aluminum bronze without coolant and lubricant. Adhesion of workpiece materials wasfound on tool's surface. Under the turning condition used in this study major wear mechanisms for turning aluminumbronze using M2 high-speed steel tool are diffusion wear, adhesive wear and plastic deformation and shear on thecrater. Partial melting of high-speed steel on the rake plays a role in the tool wear also. Major wear mechanisms forturning aluminum bronze using YW1 cemented carbide tool are diffusion wear, attrition wear and sliding wear. Tocontrol the machining temperature is essential to reduce tool wear.

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

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


    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.

  5. New explosive welding technique to weld aluminum alloy and stainless steel plates using a stainless steel intermediate plate

    Hokamoto, K.; Fujita, M. (Kumamoto Univ. (Japan). Dept. of Mechanical Engineering); Izuma, T. (Asahi Chemical Industry Co., Ltd., Siga (Japan))


    Various aluminum alloys and stainless steel were explosively welded using a thin stainless steel intermediate plate inserted between the aluminum alloy driver and stainless steel base plates. At first. the velocity change of the driver plate with flying distance is calculated using finite-difference analysis. Since the kinetic energy lost by collision affects the amount of the fused layer generated at the interface between the aluminum alloy and stainless steel, the use of a thin stainless steel intermediate plate is effective for decreasing the energy dissipated by the collision. The interfacial zone at the welded interface is composed of a fine eutectic structure of aluminum and Fe[sub 4]Al[sub 13], and the explosive welding, process of this metal combination proceeds mainly by intensive deformation of the aluminum alloy. The weldable region for various aluminum alloys is decided by the change in collision velocity and kinetic energy lost by collision, and the weldable region is decreased with the increase in the strength of the aluminum alloy.

  6. Influence of glazed zirconia on dual-cure luting agent bond strength.

    Valentino, T A; Borges, G A; Borges, L H; Platt, J A; Correr-Sobrinho, L


    The current study evaluated the influence of a novel surface treatment that uses a low-fusing porcelain glaze for promoting a bond between zirconia-based ceramic and a dual-cure resin luting agent. Bond strengths were compared with those from airborne particle abrasion, hydrofluoric acid etching, and silanization-treated surfaces. Twenty-four yttrium-stabilized tetragonal zirconia (Cercon Smart Ceramics, Degudent, Hanau, Germany) discs were fabricated and received eight surface treatments: group 1: 110 μm aluminum oxide air-borne particle abrasion; group 2: 110 μm aluminum oxide airborne particle abrasion and silane; group 3: 50 μm aluminum oxide airborne particle abrasion; group 4: 50 pm aluminum oxide airborne particle abrasion and silane; group 5: glaze and hydrofluoric acid;group 6: glaze, hydrofluoric acid, and silane;group 7: glaze and 50 pm aluminum oxide airborne particle abrasion; and group 8: glaze,50 pm aluminum oxide airborne particle abrasion and silane. After treatment, Enforce resin cement (Dentsply, Caulk, Milford, DE, USA) was used to fill an iris cut from microbore Tygontubing that was put on the ceramic surface to create 30 cylinders of resin cement in each treatment group (n=30). Micro shear bond test-ing was performed at a cross head speed of 0.5mm/min. One-way analysis of variance, and multiple comparisons were made using Tukey's test (phydrofluoric acid showed bond strength values statistically superior to groups that utilized conventional airborne particle abrasion treatments with 50 or 110 pm aluminum oxide (phydrofluoric acid showed bond strength values statistically superior to remaining groups (p<0.001). Treatment of zirconia ceramic surfaces with a glaze of low-fusing porcelain significantly increased the bond strength of a dual-cure resin luting agent to the ceramic surface.

  7. Materials Design for Joinable, High Performance Aluminum Alloys

    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

  8. Comparison of Bond in Roll-bonded and Adhesively Bonded Aluminums

    Schwensfeir, R. J., Jr.; Trenkler, G.; Delagi, R. G.; Forster, J. A.


    Lap-shear and peel test measurements of bond strength have been carried out as part of an investigation of roll bonding of 2024 and 7075 aluminum alloys. Shear strengths of the bonded material in the F temper are in the range of 14 to 16 ksi. Corresponding peel strengths are 120 to 130 lb/inch. These values, which are three to five times those reported in the literature for adhesively bonded 2024 and 7075, are a result of the true metallurgical bond achieved. The effects of heat-treating the bonded material are described and the improvements in bond strength discussed relative to the shear strength of the parent material. The significance of the findings for aerospace applications is discussed.

  9. Single-aging characteristics of 7055 aluminum alloy

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


    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.

  10. Strength Modeling Report

    Badler, N. I.; Lee, P.; Wong, S.


    Strength modeling is a complex and multi-dimensional issue. There are numerous parameters to the problem of characterizing human strength, most notably: (1) position and orientation of body joints; (2) isometric versus dynamic strength; (3) effector force versus joint torque; (4) instantaneous versus steady force; (5) active force versus reactive force; (6) presence or absence of gravity; (7) body somatotype and composition; (8) body (segment) masses; (9) muscle group envolvement; (10) muscle size; (11) fatigue; and (12) practice (training) or familiarity. In surveying the available literature on strength measurement and modeling an attempt was made to examine as many of these parameters as possible. The conclusions reached at this point toward the feasibility of implementing computationally reasonable human strength models. The assessment of accuracy of any model against a specific individual, however, will probably not be possible on any realistic scale. Taken statistically, strength modeling may be an effective tool for general questions of task feasibility and strength requirements.

  11. The strength compass

    Ledertoug, Mette Marie

    Individual paper presentation: The ‘Strength Compass’. The results of a PhDresearch project among schoolchildren (age 6-16) identifying VIAstrengths concerning age, gender, mother-tongue-langue and possible child psychiatric diagnosis. Strengths-based interventions in schools have a theoretical...... foundation in research in VIA-strengths by Seligman & Peterson (2004) and in research on strengths by Linley (2008). Based on this research the VIA-test was created for adults and later for children and youths from the age of 10. For children younger than 10 years of age Peterson & Park (2011) have made...... interviews with the parents. For younger children there has been no possibility to test for strengths. In a Danish PhD project a tool to map children’s strengths was needed for children aged 6-16 and with permission from the VIA-institute ‘The Strength Compass’ was made in cooperation with The Danish...

  12. The effect of high density electric pulses on sintered aluminum 201AB silicon carbide MMC PM compacts during plastic deformation

    Dariavach, Nader Guseinovich

    The effect of high-density electrical pulses on mechanical and structural properties of sintered aluminum SiC metal-matrix composites, fabricated by standard powder-metallurgy compaction and sintering, was investigated. Three types of phenomena where investigated during transverse rupture testing of the samples: a consolidation effect (increasing of the transverse rupture strength (TRS)), an electroplastic effect (decreasing of the flow stresses), and an increasing of the stress intensity factor by electric pulse application. It was observed, that an increase in the TRS strength of sintered powder metallurgy (PM) aluminum and aluminum metal matrix composite (MMC) compacts is a result of the electric pulse consolidation effect due to non-uniform temperature distribution around the grain boundaries. Three analytical models of the thermal effect of electric pulses on aluminum samples where considered: total temperature change of the sample due to a one electric pulse, one-dimensional steady state model and transient 2D thermal analysis of the temperature distribution around the grain boundary. The 2D transient analysis shows that the temperature rise in the grain boundary of a sintered PM aluminum sample due to an electric pulse can exceed the melting point. At the same time the temperature of the bulk material has an insignificant (melt the crack tip and increase the strength of the damaged material. The experimental study shows an increase in the stress intensity factor up to 76% for sintered aluminum PM compacts and up to 116% for sintered aluminum MMC PM compacts due to application of high-density electric pulses during transverse rapture testing.

  13. Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys and its mechanism


    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.

  14. Grain size control and superplasticity in 6013-type aluminum alloys

    Troeger, Lillianne Plaster Whitelock

    Aluminum alloys have been the material of choice for aircraft construction since the 1930's. Currently, the automotive industry is also showing an increasing interest in aluminum alloys as structural materials. 6xxx aluminum alloys possess a combination of strength and formability which makes them attractive to both industries. In addition, 6xxx alloys are highly weldable, corrosion resistant, and low in cost as compared with the 2xxx and 7xxx aluminum alloys. Superplastic forming (SPF) is a manufacturing process which exploits the phenomenon of superplasticity in which gas pressure is used to form complex-shaped parts in a single forming operation. This reduces part counts and the need for fasteners and connectors, resulting in reduced product weight. Reduced product/vehicle weight improves fuel economy. Most alloys must be specially processed for superplasticity. Much research effort has been directed at the development of thermomechanical processes for the grain refinement of aluminum alloys by static or dynamic recrystallization. to induce superplasticity. While large numbers of studies have been conducted on 2xxx, 5xxx, 7xxx, and 8xxx aluminum alloys, very few studies have been focused on the grain refinement of 6xxx aluminum alloys for superplasticity. The current research describes a new thermomechanical process for application to 6xxx aluminum alloys for grain refinement and superplasticity. The process is shown to successfully refine and induce superplasticity in an Al-Mg-Si-Cu alloy which falls within the compositional limits of both 6013 and 6111. The grain refinement is by particle-stimulated nucleation of recrystallization. The microstructural evolution during the thermomechanical processing is characterized in terms of precipitate size, shape, distribution and composition; texture; recrystallization; and grain size, shape, and thermal stability. The new process produces a statically-stable, weakly-textured, equiaxed grain structure with an average

  15. Form and stability of aluminum hydroxide complexes in dilute solution

    Hem, John David; Roberson, Charles Elmer


    Laboratory studies of solutions 4.53 x 10 -4 to 4.5 x 10 -5 molal (12.2-1.2 ppm) in aluminum, in 0.01 molal sodium perchlorate, were conducted to obtain information as to the probable behavior of aluminum in natural water. When the solutions were brought to pH 7.5-9.5 and allowed to stand for 24 hours, a precipitate was obtained which was virtually amorphous as shown by X-rays, and which had a solubility equivalent to that of boehmite. This precipitate had a hydrolysis constant (*Ks4) of 1.93 x 10 -13a. When solutions were allowed to stead at this pH range for 10 days, their precipitates gave the X-ray pattern of bayerite (*Ks4 = 1.11 > (10- 4). These hydrolysis constants were obtained at 25?C. and corrected to zero ionic strength and are in close agreement with other published values. The predominant dissolved form in this pH range is Al(OH) -4. Below neutral pH (7.0) the dissolved aluminum species consist of octahedral units in which each aluminum ion is surrounded by six water molecules or hydroxide ions. Single units such as Al(OH2)6 + 3 and AlOH(OH2)5+2 are most abundant below pH 5.0, and where the molar ratio (r) of combined hydroxide to total dissolved aluminum is low. When r is greater than 1.0, polymerization of the octahedral units occurs. When r is between 2.0 and 3.0, solutions aged for 10 days or more contained colloidal particles between 0.10 and 0.45 ? in diameter. Particles whose diameters were greater than 0.10 ? were identified by X-ray diffraction as gibbsite. Particles smaller than 0.10 ? were also present and were shown by means of the electron microscope to have a hexagonal crystal pattern. Structured material consisting of sheets of coalesced six-membered rings of aluminum ions held together by double OH bridges has a distinctive kinetic behavior. This property was used to determine amounts of polymerized material in solutions having r between 1.0 and 3.0 after aging times ranging from a few hours to more than 4 months. Aging increased the

  16. Aluminum extrusion with a deformable die

    Assaad, W.


    Aluminum extrusion process is one of metal forming processes. In aluminum extrusion, a work-piece (billet) is pressed through a die with an opening that closely resembles a desired shape of a profile. By this process, long profiles with an enormous variety of cross-sections can be produced to

  17. Sanmenxia strives to create aluminum industrial base


    <正>Contradiction between rich alumina resource and relatively weak electrolytic aluminum production capacity is the "bottleneck" inhibiting development of aluminum industry in San-menxia. During the period of "11th Five-Year Development", Sanmenxia will relay on its

  18. Wilson's disease; increased aluminum in liver.

    Yasui, M; Yoshimasu, F; Yase, Y; Uebayashi, Y


    Interaction of trace metal metabolism was studied in a patient with Wilson's dease. Atomic absorption analysis showed markedly increased urinary excretion of copper and aluminum and an increased aluminum content was found in the biopsied liver by neutron activation analysis. These findings suggest a complicated pathogenetic mechanism involving other metals besides copper in the Wilson's disease.

  19. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    Kahl, S.; Osikowicz, W.


    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strengths of the joints exceeded the tensile strengths of the base materials and were as high as 335 MPa. During soft annealing of the composite material, a 6-8-μm-thick intermetallic layer was grown at the interface. Nevertheless, tensile fracture still occurred in the heat-affected zone of the aluminum material. Electrical resistivity of the joint was smaller than resistivity of the aluminum material. Production of such composite material would result in coiled sheet material that could be subjected to further treatments such as electroplating and forming operations in an efficient and economically viable manner. The new composite material is promising for emerging automotive and industrial electrical applications.

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

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


    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. Modification Performance of WC Nanoparticles in Aluminum and an Al-Si Casting Alloy

    Borodianskiy, Konstantin; Zinigrad, Michael


    The influence of a modifier based on tungsten carbide (WC) nanoparticles is investigated first using 1 kg of bulk aluminum and then in a real industrial process using a commercial Al-Si casting alloy. The modifier is prepared by two different approaches, and its influence is investigated in pure aluminum and in commercial aluminum alloy A356. Microstructural studies show that the mean grain size in pure aluminum is reduced by 11.5 pct. Such a change usually causes an improvement in the mechanical properties of metals. Accordingly, the mechanical properties of the A356 alloy modified with WC nanoparticles are determined after T6 heat treatment and compared with unmodified specimens of the same alloy. The results obtained in the modified A356 alloy reveal unusual behavior of the mechanical properties, where the elongation of the alloys improved by 32 to 64 pct, while the tensile strength and yield strength remained unchanged. This behavior is attributable to a grain-size strengthening mechanism, where strengthening occurs due to the high concentration of grain boundaries, which act as obstacles to the motion of dislocations in the lattice.

  2. Multiscale Analysis of Open-Cell Aluminum Foam for Impact Energy Absorption

    Kim, Ji Hoon; Kim, Daeyong; Lee, Myoung-Gyu; Lee, Jong Kook


    The energy-absorbing characteristics of crash members in automotive collision play an important role in controlling the amount of damage to the passenger compartment. Aluminum foams have high strength-to-weight ratio and high deformability, thus good crashworthiness is expected while maintaining or even saving weights when foams are implemented in crash members. In order to investigate the effect of the open-cell aluminum foam fillers on impact performance and weight saving, a multiscale framework for evaluating the crashworthiness of aluminum foam-filled members is used. To circumvent the difficulties of mechanical tests on foams, a micromechanical model of the aluminum foam is constructed using the x-ray micro tomography and virtual tests are conducted for the micromechanical model to characterize the behavior of the foam. In the macroscale, the aluminum foam is represented by the crushable foam constitutive model, which is then incorporated into the impact test simulation of the foam-filled crash member. The multiscale foam-filled crash member model was validated for the high-speed impact test, which confirms that the material model characterized by the micromechanical approach represents the behavior of the open-cell foam under impact loading well. Finally, the crash member design for maximizing the energy absorption is discussed by investigating various designs from the foam-only structure to the hollow tube structure. It was found that the foam structure absorbs more energy than the hollow tube or foam-filled structure with the same weight.

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

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


    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.

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

    Zhen DONG; Qilin ZHANG


    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.

  5. Fabricating Aluminum Bronze Rotating Band for Large-Caliber Projectiles by High Velocity Arc Spraying

    Wu, Bin; Fang, Ling-hui; Chen, Xiao-lei; Zou, Zhi-qiang; Yu, Xu-hua; Chen, Gang


    The necessity of finding new rotating band materials and developing corresponding joining technologies for large-caliber projectiles has been revealed by the recent increase in the ballistic performance of high loads. In this paper, aluminum bronze coatings were fabricated by the high velocity arc spraying (HVAS) technique. Microstructure and microhardness of the prepared coatings were investigated. Ring-on-disk dry sliding wear tests were conducted in an ambient condition to examine the tribological behavior of the coatings. Quasi-static engraving processes of rotating bands made of as-sprayed aluminum bronze coating and bulk copper were studied using rate-controlled push test methodology on an MTS 810 Material Testing System. The results show that the as-sprayed aluminum bronze coatings have a dense microstructure with porosity of about 1.6%. Meanwhile, the as-sprayed coating presents a higher microhardness than pure copper. The friction coefficient of coatings is about 0.2-0.3 in the steady state. Tribological mechanisms of the as-sprayed coatings were discussed. The engraving test results show that the aluminum bronze rotating band presents high bonding strength and good plasticity. The HVAS aluminum bronze coating should be a possible substitute for the state-of-the-art copper rotating band.

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

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


    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.

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

    Tokarski, Tomasz


    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.

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

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


    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.

  9. Aluminum honeycomb impact limiter study

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))


    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  10. Recrystallization in Commercially Pure Aluminum

    Bay, Bent; Hansen, Niels


    Recrystallization behavior in commercial aluminum with a purity of 99.4 pct was studied by techniques such as high voltage electron microscopy, 100 kV transmission electron microscopy, and light microscopy. Sample parameters were the initial grain size (290 and 24 microns) and the degree of defor......Recrystallization behavior in commercial aluminum with a purity of 99.4 pct was studied by techniques such as high voltage electron microscopy, 100 kV transmission electron microscopy, and light microscopy. Sample parameters were the initial grain size (290 and 24 microns) and the degree...... (FeAl3), which start to become operative when the degree of deformation is raised from 15 to 30 pct. The temperature of nucleation and of recrystallization decreases when the degree of deformation is increased and the initial grain size is decreased. The recrystallized grain size follows the same...... trend and it is observed that the refinement of the recrystallized grain size caused by an increasing degree of deformation and decreasing initial grain size is enhanced by the FeAl3 particles (when the degree of deformation is raised from 15 to 30 pct). Finally, the structural and kinetic observations...

  11. Aluminum corrosion product release kinetics

    Edwards, Matt, E-mail:; Semmler, Jaleh; Guzonas, Dave; Chen, Hui Qun; Toor, Arshad; Hoendermis, Seanna


    Highlights: • Release of Al corrosion product was measured in simulated post-LOCA sump solutions. • Increased boron was found to enhance Al release kinetics at similar pH. • Models of Al release as functions of time, temperature, and pH were developed. - Abstract: The kinetics of aluminum corrosion product release was examined in solutions representative of post-LOCA sump water for both pressurized water and pressurized heavy-water reactors. Coupons of AA 6061 T6 were exposed to solutions in the pH 7–11 range at 40, 60, 90 and 130 °C. Solution samples were analyzed by inductively coupled plasma atomic emission spectroscopy, and coupon samples were analyzed by secondary ion mass spectrometry. The results show a distinct “boron effect” on the release kinetics, expected to be caused by an increase in the solubility of the aluminum corrosion products. New models were developed to describe both sets of data as functions of temperature, time, and pH (where applicable)

  12. Aluminum-based metal-air batteries

    Friesen, Cody A.; Martinez, Jose Antonio Bautista


    Provided in one embodiment is an electrochemical cell, comprising: (i) a plurality of electrodes, comprising a fuel electrode that comprises aluminum and an air electrode that absorbs gaseous oxygen, the electrodes being operable in a discharge mode wherein the aluminum is oxidized at the fuel electrode and oxygen is reduced at the air electrode, and (ii) an ionically conductive medium, comprising an organic solvent; wherein during non-use of the cell, the organic solvent promotes formation of a protective interface between the aluminum of the fuel electrode and the ionically conductive medium, and wherein at an onset of the discharge mode, at least some of the protective interface is removed from the aluminum to thereafter permit oxidation of the aluminum during the discharge mode.

  13. Gating of Permanent Molds for ALuminum Casting

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang


    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  14. Gelling nature of aluminum soaps in oils.

    Wang, Xiaorong; Rackaitis, Mindaugas


    Aluminum soaps are notable for their ability to form soap-hydrocarbon gels of high viscosity. For more than half a century, it has been believed that the gelling mechanism is due to a formation of polymeric chains of aluminum molecules with the aluminum atoms linking along the axis and with the fatty acid chain extended sideways. Here we report results from an investigation using high-resolution electron microscopy and rheology measurements that clearly resolve the ambiguity. Our results reveal that the gelling mechanism stems from the formation of spherical nano-sized micelles from aluminum soap molecules, and those colloidal micelle particles then aggregate into networks of highly fractal and jammed structures. The earlier proposed polymer chain-like structure is definitely incorrect. The discovery of aluminum soap particles could expand application of these materials to new technologies.

  15. Proposal of recycling system for waste aluminum

    Š. Valenčík


    Full Text Available Introduced work is focused on waste aluminum recycling process with objective to propose complex production system for recovering of aluminum and some aluminum alloys. Solution is supported by extended analysis concerning purpose, basis and system sequences for recyclation. Based on that, sources, possibilities and conditions for recycling are formed. This has been used in proposal of manufacturing system. The principle is the structural proposal of manufacturing system, which does not only differentiate the stage of aluminum melting process, but also related stages as gross separation, sizing, containerisation and batching, palletisation, stacking and some related operations. Production system respects technological specifications, requirements for rationalisation of manufacturing systems, technical and economical feasibility conditions and is considered in lower automation level. However production system solves complex problem of recycling of some types of aluminum, it improves flexibility, production, quality (melting by high enforcements and in protective atmosphere and extention of production (final products production.

  16. Trends in the global aluminum fabrication industry

    Das, Subodh; Yin, Weimin


    The aluminum fabrication industry has become more vital to the global economy as international aluminum consumption has grown steadily in the past decades. Using innovation, value, and sustainability, the aluminum industry is strengthening its position not only in traditional packaging and construction applications but also in the automotive and aerospace markets to become more competitive and to face challenges from other industries and higher industrial standards. The aluminum fabrication industry has experienced a significant geographical shift caused by rapid growth in emerging markets in countries such as Brazil, Russia, India, and China. Market growth and distribution will vary with different patterns of geography and social development; the aluminum industry must be part of the transformation and keep pace with market developments to benefit.

  17. Aluminum phosphate shows more adjuvanticity than Aluminum hydroxide in recombinant hepatitis –B vaccine formulation


    Full Text Available Background: Although a number of investigation have been carried out to find alternative adjuvants to aluminum salts in vaccine formulations, they are still extensively used due to their good track record of safety, low cost and proper adjuvanticity with a variety of antigens. Adsorption of antigens onto aluminum compounds depends heavily on electrostatic forces between adjuvant and antigen. Commercial recombinant protein hepatitis B vaccines containing aluminum hydroxide as adjuvant is facing low induction of immunity in some sections of the vaccinated population. To follow the current global efforts in finding more potent hepatitis B vaccine formulation, adjuvanticity of aluminum phosphate has been compared to aluminum hydroxide. Materials and methods: The adjuvant properties of aluminum hydroxide and aluminum phosphate in a vaccine formulation containing a locally manufactured hepatitis B (HBs surface antigen was evaluated in Balb/C mice. The formulations were administered intra peritoneally (i.p. and the titers of antibody which was induced after 28 days were determined using ELISA technique. The geometric mean of antibody titer (GMT, seroconversion and seroprotection rates, ED50 and relative potency of different formulations were determined. Results: All the adjuvanicity markers obtained in aluminum phosphate formulation were significantly higher than aluminum hydroxide. The geometric mean of antibody titer of aluminum phosphate was approximately three folds more than aluminum hydroxide. Conclusion: Aluminum phosphate showed more adjuvanticity than aluminum hydroxide in hepatitis B vaccine. Therefore the use of aluminum phosphate as adjuvant in this vaccine may lead to higher immunity with longer duration of effects in vaccinated groups.

  18. Aluminum recovery as a product with high added value using aluminum hazardous waste

    David, E., E-mail: [National Institute for Research and Development for Cryogenic and Isotopic Technologies, Street Uzinei, No. 4, P.O. Râureni, P.O. Box 7, 240050 Rm. Vâlcea (Romania); Kopac, J. [Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, SI-1000 Ljubljana (Slovenia)


    Highlights: • Granular and compact aluminum dross were physically and chemically characterized. • A relationship between density, porosity and metal content from dross was established. • Chemical reactions involving aluminum in landfill and negative consequences are shown. • A processing method for aluminum recovering from aluminum dross was developed. • Aluminum was recovered as an value product with high grade purity such as alumina. -- Abstract: The samples of hazardous aluminum solid waste such as dross were physically and chemically characterized. A relationship between density, porosity and metal content of dross was established. The paper also examines the chemical reactions involving aluminum dross in landfill and the negative consequences. To avoid environmental problems and to recovery the aluminum, a processing method was developed and aluminum was recovered as an added value product such as alumina. This method refers to a process at low temperature, in more stages: acid leaching, purification, precipitation and calcination. At the end of this process aluminum was extracted, first as Al{sup 3+} soluble ions and final as alumina product. The composition of the aluminum dross and alumina powder obtained were measured by applying the leaching tests, using atomic absorption spectrometry (AAS) and chemical analysis. The mineralogical composition of aluminum dross samples and alumina product were determined by X-ray diffraction (XRD) and the morphological characterization was performed by scanning electron microscopy (SEM). The method presented in this work allows the use of hazardous aluminum solid waste as raw material to recover an important fraction from soluble aluminum content as an added value product, alumina, with high grade purity (99.28%)

  19. Characterization of aluminum surfaces: Sorption and etching

    Polkinghorne, Jeannette Clera

    Aluminum, due to its low density and low cost, is a key material for future lightweight applications. However, like other structural materials, aluminum is subject to various forms of corrosion damage that annually costs the United States approximately 5% of its GNP [1]. The main goal is to investigate the effects of various solution anions on aluminum surfaces, and specifically probe pit initiation and inhibition. Using surface analysis techniques including X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron microscopy, results have been correlated with those obtained from electrochemical methods and a radiolabeling technique developed in the Wieckowski laboratory. Analysis of data has indicated that important variables include type of anion, solution pH, and applied electrode potential. While aggressive anions such as chloride are usually studied to elucidate corrosion processes to work ultimately toward inhibition, its corrosive properties can be successfully utilized in the drive for higher energy and smaller-scale storage devices. Fundamental information gained regarding anion interaction with the aluminum surface can be applied to tailor etch processes. Standard electrochemical techniques and SEM are respectively used to etch and analyze the aluminum substrate. Aluminum electrolytic capacitors are comprised of aluminum anode foil covered by an anodically grown aluminum oxide dielectric film, electrolytic paper impregnated with electrolyte, and aluminum cathode foil. Two main processes are involved in the fabrication of aluminum electrolytic capacitors, namely etching and anodic oxide formation. Etching of the anode foil results in a higher surface area (up to 20 times area enlargement compared to unetched foil) that translates into a higher capacitance gain, permitting more compact and lighter capacitor manufacture. Anodic oxide formation on the anode, creates the required dielectric to withstand high voltage operation. A

  20. Joining of dissimilar metals by diffusion bonding. Titanium alloy with aluminum

    Akca, Enes [International Univ. of Sarajevo (Bosnia and Herzegovina). Research and Development Center; International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering; Gursel, Ali [International Univ. of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering


    This paper presents a novel diffusion bonding process of commercially pure aluminum to Ti-6Al-4V alloy at 520, 560, 600 and 640 C for 30, 45 and 60 minutes under argon gas shielding without the use of interlayer. The approach is to overcome the difficulties in fusion welding of dissimilar alloys. Diffusion bonding is a dissimilar metal welding process which can be applied to the materials without causing any physical deformations. Processed samples were metallographically prepared, optically examined followed by Vickers microhardness test and subjected to tensile test in order to determine joint strength. Scanning electron microscopy and energy dispersive spectroscopy were used in this work to investigate the compositional changes across the joint region. Elemental composition of the region has been successfully defined between titanium alloy and aluminum. The maximum tensile strength was obtained from the samples bonded at the highest temperatures of 600 and 640 C.

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

    WANG Yu


    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.

  2. Graphene-reinforced aluminum matrix composites prepared by spark plasma sintering

    Wen-ming Tian; Song-mei Li; Bo Wang; Xin Chen; Jian-hua Liu; Mei Yu


    Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sinter-ing (SPS). The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide (Al4C3) is not formed during SPS processing. Further addition of graphene (above 1wt%) results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.

  3. Role of welding parameters on interfacial bonding in dissimilar steel/aluminum friction stir welds

    Z. Shen


    Full Text Available In this study, lap welds between Al5754 to DP600 steel (aluminum plate top, and steel plate bottom were manufactured by friction stir welding (FSW. The effects of welding parameters (i.e. travel speeds and penetration depth into lower steel sheet on the interfacial bonding, tensile strength, and failure mechanism were investigated. The results show that intermetallic compound of Fe4Al13 was detected at the Al/Fe interface. The weld strength increases significantly by increasing the penetration depth into the lower steel substrate at all travel speeds. The failure mode under overlap shear loadings is premature failure through the aluminum substrate when the penetration depth is more than 0.17 mm, and shear fracture when the penetration depth is less than 0.17 mm.




    Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.

  5. Hydrogen storage in sodium aluminum hydride.

    Ozolins, Vidvuds; Herberg, J.L. (Lawrence Livermore National Laboratories, Livermore, CA); McCarty, Kevin F.; Maxwell, Robert S. (Lawrence Livermore National Laboratories, Livermore, CA); Stumpf, Roland Rudolph; Majzoub, Eric H.


    Sodium aluminum hydride, NaAlH{sub 4}, has been studied for use as a hydrogen storage material. The effect of Ti, as a few mol. % dopant in the system to increase kinetics of hydrogen sorption, is studied with respect to changes in lattice structure of the crystal. No Ti substitution is found in the crystal lattice. Electronic structure calculations indicate that the NaAlH{sub 4} and Na{sub 3}AlH{sub 6} structures are complex-ionic hydrides with Na{sup +} cations and AlH{sub 4}{sup -} and AlH{sub 6}{sup 3-} anions, respectively. Compound formation studies indicate the primary Ti-compound formed when doping the material at 33 at. % is TiAl{sub 3} , and likely Ti-Al compounds at lower doping rates. A general study of sorption kinetics of NaAlH{sub 4}, when doped with a variety of Ti-halide compounds, indicates a uniform response with the kinetics similar for all dopants. NMR multiple quantum studies of solution-doped samples indicate solvent interaction with the doped alanate. Raman spectroscopy was used to study the lattice dynamics of NaAlH{sub 4}, and illustrated the molecular ionic nature of the lattice as a separation of vibrational modes between the AlH{sub 4}{sup -} anion-modes and lattice-modes. In-situ Raman measurements indicate a stable AlH{sub 4}{sup -} anion that is stable at the melting temperature of NaAlH{sub 4}, indicating that Ti-dopants must affect the Al-H bond strength.

  6. Influece of the austempering temperature on the tensile strength of the austempered ductile iron (ADI samples

    S. Savićević


    Full Text Available Austempered Ductile Iron (ADI is a class of ductile iron subjected to a two-step heat treatment process – austenitization and austempering. The heat treatment gives to ADI a high value of tensile strength and an especially good strength-to-weight ratio. However, designers in most cases are unfamiliar with this material that can compete favorably with steel and aluminum castings, weldments and forgings. The high tensile strength of ADI is the result of its unique ausferrite microstructure. In this paper, an investigation of the influence of the austempering temperature on the tensile strength of the ADI samples is presented.

  7. Strength of Plastics,

    evaluating the strength of structural elements is examined. The book is intended for design engineers, factory laboratory personnel, scientific research workers, and the design institutes. (Author-PL)

  8. The Role of Second Phase Intermetallic Particles on the Spall Failure of 5083 Aluminum


    Thomas GJ, Hazell PJ (2010) A study on the strength of an armour -grade aluminum under high strain-rate loading. J Appl Phys 107:123508 3. Whelchel RL...weight and strain-hardened material used in high strain-rate applications such as those experienced under shock loading. Symmetric real-time (in...experienced under shock loading. Symmetric real-time (in situ) and end-state (ex situ recovery) plate impact shock experiments were conducted to

  9. Effect of ultrasonic power on wedge bonding strength and interface microstructure

    WANG Fu-liang; LI Jun-hui; HAN Lei; ZHONG Jue


    During the aluminum wire wedge bonding, the ultrasonic power and bonding strength were obtained. Based on those data, the relationship between ultrasonic power and bonding strength was studied. The results show that: 1) ultrasonic power is affected by ultrasonic power ratio and other uncontrolled factors such as asymmetric substrate quality, unstable restriction on the interface between wedge tool and aluminum wire; 2) when ultrasonic power is less than 1.0 W, increasing ultrasonic power leads to increasing bonding strength and decreasing failure bonding; on the contrary, when ultrasonic power is greater than 1.6 W, increasing power leads to decreasing bonding strength and increasing failure bonding; 3) only when ultrasonic power is between 1.0 W and 1.6 W, can stable and high yield bonding be reached. Finally, the microstructure of bonding interface was observed, and a ring-shaped bond pattern is founded in the center and friction scrape besides the ring area.

  10. Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

    Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)


    The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

  11. Strength Training and Your Child

    ... Feeding Your 1- to 2-Year-Old Strength Training and Your Child KidsHealth > For Parents > Strength Training ... prevent injuries and speed up recovery. About Strength Training Strength training is the practice of using free ...

  12. Taguchi analysis of dissimilar aluminum sheets joined by friction stir spot welding

    Mustafa Kemal BİLİCİ


    Full Text Available In recent years, the welding of materials of new and complex structure constitutes a problem for the industry. The solid state welding method for joining of these materials were effective. Sheets produced from aluminum and aluminum alloys, especially in areas such as automotive, railway and defense industry have revealed the requirement of the application of solid state welding methods. The friction stir spot welding is one of the solid state welding method. Welding parameters is very important FSSW in order to obtain the maximum welding strength in FSSW. SKNK as parameters (tool rotational speed, depth, dive team, team and team inclination angle of standby time is selected. In this study has investigated the joining of AA2024-T3 and AA5754-H22 aluminum alloy sheets with FSSW technique by Taguchi analysis. “The highest -the better” quality control characteristic using the Analysis of Variance (ANOVA method were obtained the optimum welding parameters. The results have been analyzed both the graphical methods and numerical data. The most important parameters affecting the weld tensile strength were detected as tool rotation speed (44.74% and the team of waiting time (31.60%. Weld tensile strength by Taguchi analysis result conducted for comparing experiments the increased by 42% compared to the initial parameters.Keywords: Friction stir spot welding, Mechanical properties, Taguchi method, Optimization

  13. Development of Alcoa aluminum foam products

    Bryant, J.D.; Crowley, M.D.; Wang, W.; Wilhelmy, D.M.; Hunter, D.E. [Alcoa Technical Center, Alcoa Center, PA (United States)


    A new lightweight aluminum foam product was described. The foam was made through the controlled decomposition of carbonate powders within molten aluminum and was able to resist both coalescence and drainage. The fine-celled aluminum foam derived its physical and mechanical properties from the properties of the aluminum alloy matrix from which they were produced. The rheology of the molten aluminum was modified to provide a superior mesostructure. Stabilization was achieved by creating a solid-gas-liquid suspension initiated by the addition of carbonates into an aluminum alloy melt. A cascade of chemical reactions then occurred within the melt to create a foamable suspension. Carbon monoxide (CO) was generated to initiate an additional sequence of chemical reactions which resulted in the formation of solid particles within the liquid metal. CO reacted with liquid Al to form graphite. The graphite then reacted with Al to form aluminum carbide (Al{sub 4}C{sub 3}). The microstructural, mesostructural, and mechanical character of the foams produced under different processing conditions were examined. Details of experimental test procedures were also described. It was concluded that the specific crush energy absorption was as high as 20 kJ/kg. The foam exhibited a bending stiffness that was approximately 20 to 30 times higher than balsa and polymer foams. 14 refs., 2 tabs., 7 figs.

  14. Evaluating the aluminum content of pressed dross

    Kevorkijan, V.


    Pressing of skimmed hot drosses in a press is a very popular technology for cooling hot dross and obtaining the maximum in-house recovery of aluminum alloy. As a result of the pressing action, part of the molten aluminum alloy is squeezed out, while the rest of the free metal remains in the pressed skulls. Thus, pressed skulls are a valuable waste product, consisting of 30 70 wt.% free aluminum. Other constituents are aluminum oxide and oxides of alloying metals. Pressed skulls are generally valued on a free-metal recovery basis, which necessarily involves practical determination of their free aluminum content. Because most analytical methods are limited to the laboratory level and representative sub-samples, there is a practical interest in developing a routine, cost-effective, and non-destructive method to predict the free aluminum content in entire pressed skulls, based on their density. To develop such a method, a relation between the bulk density, porosity, and free aluminum content of pressed skulls was established. This article offers a review of those experiments and an analysis of their results.

  15. Thermal and tensile strength testing of thermally-conductive adhesives and carbon foam

    Chertok, M.; Fu, M.; Irving, M.; Neher, C.; Shi, M.; Tolfa, K.; Tripathi, M.; Vinson, Y.; Wang, R.; Zheng, G.


    Future collider detectors, including silicon tracking detectors planned for the High Luminosity LHC, will require components and mechanical structures providing unprecedented strength-to-mass ratios, thermal conductivity, and radiation tolerance. This paper studies carbon foam used in conjunction with thermally conductive epoxy and thermally conductive tape for such applications. Thermal performance and tensile strength measurements of aluminum-carbon foam-adhesive stacks are reported, along with initial radiation damage test results.

  16. Mechanical Behavior of Aluminum (AlSi10Mg)-RHA Composite

    S.D.Saravanan; M. Senthilkumar


    Rice Husk Ash (RHA) of three different particle size ranges (50 – 75 μm), (75 – 100μm) and (100 – 150μm) in 3, 6, 9 and 12 % by weight was reinforced with the aluminium alloy using stir cast route. The microstructure and mechanical properties of the fabricated composites were analyzed. The results reveal that the tensile strength, compressive strength and hardness of the aluminum alloy composites decrease with increase in particle size of RHA. But increase in the weight fractions of RHA parti...

  17. Lead exposure from aluminum cookware in Cameroon

    Weidenhamer, Jeffrey D.; Kobunski, Peter A. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Kuepouo, Gilbert [Research and Education Centre for Development (CREPD), Yaounde (Cameroon); Corbin, Rebecca W. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Gottesfeld, Perry, E-mail: [Occupational Knowledge International, San Francisco, CA (United States)


    Blood lead levels have decreased following the removal of lead from gasoline in most of the world. However, numerous recent studies provide evidence that elevated blood lead levels persist in many low and middle-income countries around the world at much higher prevalence than in the more developed countries. One potential source of lead exposure that has not been widely investigated is the leaching of lead from artisanal aluminum cookware, which is commonly used in the developing world. Twenty-nine samples of aluminum cookware and utensils manufactured by local artisans in Cameroon were collected and analyzed for their potential to release lead during cooking. Source materials for this cookware included scrap metal such as engine parts, radiators, cans, and construction materials. The lead content of this cookware is relatively low (< 1000 ppm by X-ray fluorescence), however significant amounts of lead, as well as aluminum and cadmium were released from many of the samples using dilute acetic acid extractions at boiling and ambient temperatures. Potential exposures to lead per serving were estimated to be as high as 260 μg, indicating that such cookware can pose a serious health hazard. We conclude that lead, aluminum and cadmium can migrate from this aluminum cookware during cooking and enter food at levels exceeding recommended public health guidelines. Our results support the need to regulate lead content of materials used to manufacture these pots. Artisanal aluminum cookware may be a major contributor to lead poisoning throughout the developing world. Testing of aluminum cookware in other developing countries is warranted. - Highlights: • Cookware is manufactured in Cameroon from scrap aluminum including car parts. • Twenty-nine cookware samples were evaluated for their potential to leach lead. • Boiling extractions to simulate the effects of cooking released significant lead. • Potential lead exposures per serving are estimated as high as 260 μg.

  18. Strengths of Remarried Families.

    Knaub, Patricia Kain; And Others


    Focuses on remarried families' (N=80) perceptions of family strengths, marital satisfaction, and adjustment to the remarried situation. Results indicated that although most would like to make some changes, scores on the measurements used were high. A supportive environment was the most important predictor of family strength and success. (JAC)

  19. Building on Our Strengths.

    Hill, Robert


    Comments on the feeling that the American family is disintegrating, and that many criticisms traditionally made about Black families are now made about White families. Suggests that people need to stress family strengths. As an example, five major strengths of Black families are described: flexibility, work and achievement ethics, religiosity, and…

  20. Explosive welding technique for joining aluminum and steel tubes

    Wakefield, M. E.


    Silver sheet is wrapped around aluminum portion of joint. Mylar powder box is wrapped over silver sheet. Explosion welds silver to aluminum. Stainless-steel tube is placed over silver-aluminum interface. Mylar powder box, covered with Mylar tape, is wrapped around steel member. Explosion welds steel to silver-aluminum interface.

  1. Nanshan Aluminum Reached Strategic Cooperation with CSR Corporation Limited


    As a key supplier of aluminum profiles and aluminum plate,sheet and trip products for CSR Corporation Limited,Nanshan Aluminum will join hands with CSR Corporation Limited to reach strategic cooperation.On January 5,Nanshan Aluminum signed strategic cooperation agreement with CSR Sifang Locomotive&Rolling; Stock Co.,Ltd,both

  2. Changes in porosity of foamed aluminum during solidification


    In order to control the porosity of foamed aluminum, the changes in the porosity of foamed aluminum melt in the processes of foaming and solidification, the distribution of the porosity of foamed aluminum, and the relationship between them were studied. The results indicated that the porosity of foamed aluminum coincides well with the foaming time.

  3. Formulation and method for preparing gels comprising hydrous aluminum oxide

    Collins, Jack L.


    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

  4. Fatigue analysis of aluminum drill pipes

    João Carlos Ribeiro Plácido


    Full Text Available An experimental program was performed to investigate the fundamental fatigue mechanisms of aluminum drill pipes. Initially, the fatigue properties were determined through small-scale tests performed in an optic-mechanical fatigue apparatus. Additionally, full-scale fatigue tests were carried out with three aluminum drill pipe specimens under combined loading of cyclic bending and constant axial tension. Finally, a finite element model was developed to simulate the stress field along the aluminum drill pipe during the fatigue tests and to estimate the stress concentration factors inside the tool joints. By this way, it was possible to estimate the stress values in regions not monitored during the fatigue tests.

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



    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.

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

    Felipe García-Vázquez

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

  7. Mechanical and thermal cycling effects on the flexural strength of glass ceramics fused to titanium

    Vasquez, Vanessa; Ozcan, Mutlu; Nishioka, Renato; Souza, Rodrigo; Mesquita, Alfredo; Pavanelli, Carlos


    This study evaluated the effects of mechanical and thermal cycling on the flexural strength (ISO 9693) of three brands of ceramics fused to commercially pure titanium (cpTi). Metallic frameworks of 25 x 3 x 0.5 mm dimensions (N = 84) were cast in cpTi, followed by 150-mu m aluminum oxide airborne pa

  8. Mechanical and thermal cycling effects on the flexural strength of glass ceramics fused to titanium

    Vasquez, Vanessa; Ozcan, Mutlu; Nishioka, Renato; Souza, Rodrigo; Mesquita, Alfredo; Pavanelli, Carlos

    This study evaluated the effects of mechanical and thermal cycling on the flexural strength (ISO 9693) of three brands of ceramics fused to commercially pure titanium (cpTi). Metallic frameworks of 25 x 3 x 0.5 mm dimensions (N = 84) were cast in cpTi, followed by 150-mu m aluminum oxide airborne

  9. Joint performance of CO2 laser beam welding 5083-H321 aluminum alloy

    Qi Junfeng; Zhang Dongyun; Xiao Rongshi; Chen Kai; Zuo Tiechuan


    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).

  10. Static and dynamic behavior of carbon fiber reinforced aluminum (CARALL) laminates

    Dhaliwal, Gurpinder Singh

    /w aluminum & CFRP layers. The threshold impact energy, energy at which perforation failure was induced in all metallic and fiber reinforced layers for these laminates was found to be around 31J. Finite element analysis utilizing LS-DYNA software was performed to predict load-displacement history, delamination area, absorbed energy, damage morphologies on impacted and non-impacted sides and tensile failures of CFRP layers for an impact event at three different energy levels. Delamination at the aluminum and carbon fiber layers interfaces was modeled by using with traction separation law and damage criterion proposed by Benzeggagh-Kenane was used for interface damage evolution. Predicted impact behavior results match well with experimental results. Length-wise compression after impact static tests was conducted for impacted and non-impacted samples to determine the residual strength of these fiber metal laminates after the impact event. By comparing FMLs systems cured with and without using polyester surfacing veil cloth layers in terms of residual strength at the same impact energy, it is found that the FMLs having cloth layers provides higher residual strength than the regular FMLs cured without cloth layers composite system due to the higher interlaminar strength of the composite system. These results provide a clear understanding of the failure modes of these FMLs under different loading conditions and how they influence the overall composite behavior. A unique contribution of the thesis work is the investigation of the effect of resin rich polyester veil cloth on flexural, tensile, low-velocity impact & compression after impact characteristics of these carbon fiber reinforced aluminum laminates. These results can be used in designing lightweight automotive and aerospace components.

  11. A Steam-Plasma Igniter for Aluminum Powder Combustion

    Sanghyup, Lee; Kwanyoung, Noh; Jihwan, Lim; Woongsup, Yoon


    High-temperature ignition is essential for the ignition and combustion of energetic metal fuels, including aluminum and magnesium particles which are protected by their high-melting-temperature oxides. A plasma torch characterized by an ultrahigh-temperature plasma plume fulfills such high-temperature ignition conditions. A new steam plasma igniter is designed and successfully validated by aluminum power ignition and combustion tests. The steam plasma rapidly stabilizes in both plasma and steam jet modes. Parametric investigation of the steam plasma jet is conducted in terms of arc strength. A high-speed camera and an oscilloscope method visualize the discharge characteristics, and optical emission spectroscopy measures the thermochemical properties of the plasma jet. The diatomic molecule OH fitting method, the Boltzmann plot method, and short exposure capturing with an intensified charge coupled device record the axial distributions of the rotational gas temperature, excitation temperature, and OH radical distribution, respectively. The excitation temperature at the nozzle tip is near 5500 K, and the gas temperature is 5400 K.

  12. Aluminum-Scandium: A Material for Semiconductor Packaging

    Geissler, Ute; Thomas, Sven; Schneider-Ramelow, Martin; Mukhopadhyay, Biswajit; Lang, Klaus-Dieter


    A well-known aluminum-scandium (Al-Sc) alloy, already used in lightweight sports equipment, is about to be established for use in electronic packaging. One application for Al-Sc alloy is manufacture of bonding wires. The special feature of the alloy is its ability to harden by precipitation. The new bonding wires with electrical conductivity similar to pure Al wires can be processed on common wire bonders for aluminum wedge/wedge (w/w) bonding. The wires exhibit very fine-grained microstructure. Small Al3Sc particles are the main reason for its high strength and prevent recrystallization and grain growth at higher temperatures (>150°C). After the wire-bonding process, the interface is well closed. Reliability investigations by active power cycling demonstrated considerably improved lifetime compared with pure Al heavy wires. Furthermore, the Al-Sc alloy was sputter-deposited onto silicon wafer to test it as chip metallization in copper (Cu) ball/wedge bonding technology. After deposition, the layers exhibited fine-grained columnar structure and small coherent Al3Sc particles with dimensions of a few nanometers. These particles inhibit softening processes such as Al splashing in fine wire bonding processes and increase the thickness of remnant Al under the copper balls to 85% of the initial thickness.

  13. Spot brazing of aluminum to copper with a cover plate

    Hayashi, Junya; Miyazawa, Yasuyuki


    It is difficult to join dissimilar metals when an intermetallic compound is formed at the joining interface. Spot brazing can be accomplished in a short time by resistance heating. Therefore, it is said that the formation of a intermetallic compound can be prevented. In this study, aluminum and copper were joined by spot brazing with a cover plate. The cover plate was used to supply heat to base metals and prevent heat dissipation from the base metals. The ability to braze Al and Cu was investigated by observation and analysis. Pure aluminum (A1050) plate and oxygen-free copper (C1020) plate were used as base metals. Cu-Ni-Sn-P brazing filler was used as the brazing filler metal. SPCC was employed as cover plate. Brazing was done with a micro spot welder under an argon gas atmosphere. Brazing ability was estimated by tensile shear strength and cross sectional microstructure observation. Al and Cu can be joined by spot brazing with Cu-Ni-Sn-P brazing filler and cover plate.

  14. Evaluation of borated aluminum products for criticality control in 235-F

    Crouch, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    Plutonium-containing materials are destined for storage in the 235-F vault. The projected amount of stored materials will require the presence of neutron absorber materials. The leading design concept is for the neutron absorber materials to be in non-load-bearing borated aluminum plates lining the walls of the vault. A comprehensive evaluation of the borated aluminum plate materials was performed to identify a suitable material, and verify that these materials would remain effective as neutron absorbers under normal service conditions and for design-basis events, including the fire accident scenario, throughout a 20-year service life. Aluminum 1100 with boron additions is the recommended neutron absorber material for plutonium material storage in the 235-F vault based on boron loading capacity and durability in the storage environment. Borated aluminum 1100 is commercially available up to 4.5 wt. % boron. A detailed comparison was made of the physical, mechanical, and corrosion properties of borated aluminum alloy 1100 to standard alloy 1100-O1 to demonstrate near-equivalency in properties and to justify application of alloy 1100-O properties to the borated product as needed for the degradation analysis. The expected degradation of the borated aluminum is extremely low for storage conditions, including the bounding scenario of an aggressive atmospheric condition. A maximum loss of 0.00029 inches/year would be expected under potentially aggressive atmospheric conditions and would result in a fractional loss of only 0.42 wt. % of the boron present in a 7mm plate for a 20-year storage period. The fraction of Boron-10 consumption by spontaneous neutrons is expected to be less than 10-8 for the 20-year storage in 235-F fully loaded with Pu materials. The borated aluminum alloy 1100 will be thermally stable and unaltered up to near-melt temperature (643°C). Mechanical testing data at elevated temperatures show that the strengths (yield and ultimate) of the borated

  15. Evaluation of borated aluminum products for criticality control in 235-F

    Duncan, A. [Savannah River Site (SRS), Aiken, SC (United States); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States)


    strengths (yield and ultimate) of the borated aluminum alloy 1100 are equal or greater than those of aluminum alloy 1100-O, but with less ductility. A fire accident scenario would not adversely impact the configuration or the neutron-absorbing performance of non-load-bearing plates. No additional surveillances are needed to verify these conclusions. However, if a design-basis fire or other off-normal event occurs during the storage period, it is recommended to verify that the conditions of the event have been covered by those assumed in this report.

  16. Coordination Structure of Aluminum in Magnesium Aluminum Hydroxide Studied by 27Al NMR


    The coordination structure of aluminum in magnesium aluminum hydroxide was studiedby 27Al NMR. The result showed that tetrahedral aluminum (AlⅣ) existed in magnesiumaluminum hydroxide, and the contents of AlⅣ increased with the increase of the ratio of Al/Mg andwith the peptizing temperature. AlⅣ originated from the so-called Al13 polymer with the structureof one Al tetrahedron surrounded by twelve Al octahedrons.

  17. Vibration characteristics of aluminum surface subjected to ultrasonic waves and their effect on wetting behavior of solder droplets.

    Ma, Lin; Xu, Zhiwu; Zheng, Kun; Yan, Jiuchun; Yang, Shiqin


    The vibration characteristics of an aluminum surface subjected to ultrasonic waves were investigated with a combination of numerical simulation and experimental testing. The wetting behavior of solder droplets on the vibrating aluminum surface was also examined. The results show that the vibration pattern of the aluminum surface is inhomogeneous. The amplitude of the aluminum surface exceeds the excitation amplitude in some zones, while the amplitude decreases nearly to zero in other zones. The distribution of the zero-amplitude zones is much less dependent on the strength of the vibration than on the location of the vibration source. The surface of the liquid solder vibrates at an ultrasonic frequency that is higher than the vibration source, and the amplitude of the liquid solder is almost twice that of the aluminum surface. The vibration of the surface of the base metal (liquid solder) correlates with the oxide film removal effect. Significant removal of the oxide film can be achieved within 2s when the amplitude of the aluminum surface is higher than 5.4 μm or when the amplitude of the liquid solder surface is higher than 10.2 μm.

  18. Texture in equal-channel angular pressed aluminum and nickel

    Vogel, S.C.; Beyerlein, I.J.; Bourke, M.A.M.; Tome, C.N.; Rangaswamy, P. [Los Alamos National Lab., Los Alamos, NM (United States); Xu, C.; Langdon, T.G. [Univ. of Southern California, Los Angeles, CA (United States)


    Nano-structured metals with advantageous mechanical properties can be produced using severe plastic deformation techniques such as equal channel angular pressing (ECAP). Metals and alloys processed by ECAP have much higher yield strengths than the equivalent unprocessed material while retaining high ductilities, an extremely attractive combination of properties. Implicit in the process are the introduction of repetitive shear strains of 100% which introduce texture, the modeling of which is challenging. In this work, we present results from a neutron diffraction study on aluminum and nickel samples processed by ECAP. The results are compared to predictions from a visco-plastic self-consistent (VPSC) model. By taking into account grain-grain interactions in the model the agreement between the predicted and measured orientation distributions is improved. The results show also that the initial texture affects the texture evolution, at least up to strains of the order of {proportional_to}1, i.e. one ECAP pass. (orig.)

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

    Yang Bin


    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. Formation of anodic aluminum oxide with serrated nanochannels.

    Li, Dongdong; Zhao, Liang; Jiang, Chuanhai; Lu, Jia G


    We report a simple and robust method to self-assemble porous anodic aluminum oxide membranes with serrated nanochannels by anodizing in phosphoric acid solution. Due to high field conduction and anionic incorporation, an increase of anodizing voltage leads to an increase of the impurity levels and also the field strength across barrier layer. On the basis of both experiment and simulation results, the initiation and formation of serrated channels are attributed to the evolution of oxygen gas bubbles followed by plastic deformation in the oxide film. Alternating anodization in oxalic and phosphoric acids is applied to construct multilayered membranes with smooth and serrated channels, demonstrating a unique way to design and construct a three-dimensional hierarchical system with controllable morphology and composition.