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Sample records for aluminium alloy aa6056

  1. Investigation on laser brazing AA6056 Al alloy to XC18 low-carbon steel

    NASA Astrophysics Data System (ADS)

    Ding, Jianjun; Li, Feiqun; Qu, Feng; Peyre, Patrice; Fabbro, Remy

    2005-01-01

    Based on the studies of influence of YAG laser heating conditions for Al alloy melt and steel on wettability, the mechanics of the laser overlap braze welding of 6056 Al and XC18 steel sheet has been investigated. Under the temperature range which is above the melting point of the Al alloy and below the melting point of the steel, two dissimilar metals can be joined by means of laser braze welding. There is no crack observed in the joining area, i.e. Al-Fe intermetallic phase (Fe3Al/FeAl/FeAl3/Fe2Al5) layer formed by solution and diffusion between liquid-solid interface. The temperature range can be defined as the process temperatures of laser braze welding of Al-Fe materials. Selecting a higher laser heating temperature can improve the wettability of Al melt to steel surface, but the intermetallic phase layer is also thicker. When the laser heating temperature is so high that the joining surface of steel is melted, there is a crack trend in the joining area.

  2. Extrusion of aluminium alloys

    SciTech Connect

    Sheppard, T.

    1999-01-01

    In recent years the importance of extruded alloys has increased due to the decline in copper extrusion, increased use in structural applications, environmental impact and reduced energy consumption. There have also been huge technical advances. This text provides comprehensive coverage of the metallurgical, mathematical and practical features of the process. The contents include: continuum principles; metallurgical features affecting the extrusion of Al-alloys; extrusion processing; homogenization and extrusion conditions for specific alloys; processing of 6XXX alloys; plant utilization; Appendix A: specification of AA alloys and DIN equivalents; Appendix B: chemical compositions; and Appendix C: typical properties.

  3. Investigation of the formability of aluminium alloys at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Tisza, M.; Budai, D.; Kovács, P. Z.; Lukács, Zs

    2016-11-01

    Aluminium alloys are more and more widely applied in car body manufacturing. Increasing the formability of aluminium alloys are one of the most relevant tasks in todays’ research topics. In this paper, the focus will be on the investigation of the formability of aluminium alloys concerning those material grades that are more widely applied in the automotive industry including the 5xxx and 6xxx aluminium alloy series. Recently, besides the cold forming of aluminium sheets the forming of aluminium alloys at elevated temperatures became a hot research topic, too. In our experimental investigations, we mostly examined the EN AW 5754 and EN AW 6082 aluminium alloys at elevated temperatures. We analysed the effect of various material and process parameters (e.g. temperature, sheet thickness) on the formability of aluminium alloys with particular emphasis on the Forming Limit Diagrams at elevated temperatures in order to find the optimum forming conditions for these alloys.

  4. Precipitate strengthening of nanostructured aluminium alloy.

    PubMed

    Wawer, Kinga; Lewandowska, Malgorzata; Kurzydlowski, Krzysztof J

    2012-11-01

    Grain boundaries and precipitates are the major microstructural features influencing the mechanical properties of metals and alloys. Refinement of the grain size to the nanometre scale brings about a significant increase in the mechanical strength of the materials because of the increased number of grain boundaries which act as obstacles to sliding dislocations. A similar effect is obtained if nanoscale precipitates are uniformly distributed in coarse grained matrix. The development of nanograin sized alloys raises the important question of whether or not these two mechanisms are "additive" and precipitate strengthening is effective in nanostructured materials. In the reported work, hydrostatic extrusion (HE) was used to obtain nanostructured 7475 aluminium alloy. Nanosized precipitates were obtained by post-HE annealing. It was found that such annealing at the low temperatures (100 degrees C) results in a significant increase in the microhardness (HV0.2) and strength of the nanostructured 7475 aluminium alloy. These results are discussed in terms of the interplay between the precipitation and deformation of nanocrystalline metals.

  5. Acoustic Emission from the Aluminium Alloy 7050.

    DTIC Science & Technology

    1979-10-01

    thick-section applications, has good stress - corrosion resistance, and is now being used in airframe construction. In this report, we present our AE...160.00 1S0.00 200.90 2SO.I9 TIMlE (sec) Fig. 8 Count-rate/time and nominal- stress /time curves for 7050 C-specimen (a) and 0-speimen lb). CO 0 CC 0T LLQ...A094 38" AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA) F/6 11/6 ACOUSTIC EMISSION FROM THE ALUMINIUM ALLOY 7050 .(U) OCT 79 S M COUSLAND, C M SCALA

  6. Forming of aluminium alloy friction stir welds

    NASA Astrophysics Data System (ADS)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  7. Deviatoric response of the aluminium alloy, 5083

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, Gareth; Hazell, Paul; Millett, Jeremy; Bourne, Neil

    2009-06-01

    Aluminium alloys such as 5083 are established light weight armour materials. As such, the shock response of these materials is of great importance. The shear strength of a material under shock loading provides an insight into its ballistic performance. In this investigation embedded manganin stress gauges have been employed to measure both the longitudinal and lateral components of stress during plate impact experiments over a range of impact stresses. In turn, these results were used to determine the shear strength and to investigate the time dependence of lateral stress behind the shock front to give an indication of material response.

  8. Aluminium alloys in municipal solid waste incineration bottom ash.

    PubMed

    Hu, Yanjun; Rem, Peter

    2009-05-01

    With the increasing growth of incineration of household waste, more and more aluminium is retained in municipal solid waste incinerator bottom ash. Therefore recycling of aluminium from bottom ash becomes increasingly important. Previous research suggests that aluminium from different sources is found in different size fractions resulting in different recycling rates. The purpose of this study was to develop analytical and sampling techniques to measure the particle size distribution of individual alloys in bottom ash. In particular, cast aluminium alloys were investigated. Based on the particle size distribution it was computed how well these alloys were recovered in a typical state-of-the-art treatment plant. Assessment of the cast alloy distribution was carried out by wet physical separation processes, as well as chemical methods, X-ray fluorescence analysis and electron microprobe analysis. The results from laboratory analyses showed that cast alloys tend to concentrate in the coarser fractions and therefore are better recovered in bottom ash treatment plants.

  9. Examples of liquiq metal embrittlement in industrial aluminium alloys

    NASA Astrophysics Data System (ADS)

    Bréchet, Y.; Rodine, A.; Véron, M.; Péron, S.; Deschamps, A.

    2002-09-01

    Liquid metal embrittlement (LME) phenomena were investigated in two industrial aluminium alloys. Gallium penetration in 7010 alloys was systematically investigated to shed light on the effect of microstructure and plasticity ahead of the crack tip. Hot temperature shortness in 5083 alloy is given as an example of cleavage induced by LME.

  10. Computer modelling of age hardening for cast aluminium alloys

    NASA Astrophysics Data System (ADS)

    Wu, Linda; Ferguson, W. George

    2009-08-01

    Age hardening, or precipitation hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. Although various age hardening models have been developed for aluminium alloys, from the large volume of literature reviewed, it appears that the bulk of the research has been concentrated on wrought aluminium alloys, only a few of the established precipitation models have been applied to the casting aluminium alloys. In the present work, there are two modelling methods that have been developed and applied to the casting aluminium alloys A356 and A357. One is based on the Shercliff-Ashby methodology to produce a process model, by which we mean a mathematical relationship between process variables (alloy composition, ageing temperature and time) and material properties (yield strength or hardness) through microstructure evolution (precipitate radius, volume fraction). The other method is based on the Kampmann and Wagner Numerical (KWN) model which deals with concomitant nucleation, growth and coarsening and is thus capable of predicting the full evolution of the particle size distribution and then a strength model is used to evaluate the resulting change in hardness or yield strength at room temperature by taking into account contributions from lattice resistance, solid solution hardening and precipitation hardening.

  11. Ageing characteristics of aluminium alloy aluminosilicate discontinuous fiber reinforced composites

    SciTech Connect

    Nath, D.; Singh, V.

    1999-03-05

    Development of continuous fiber reinforced metal matrix composites is aimed at providing high specific strength and stiffness needed for aerospace and some critical high temperature structural applications. Considerable efforts have been made, during the last decade, to improve the strength of age-hardening aluminium alloy matrix composites by suitable heat treatment. It has also been well established that age-hardenable aluminium alloy composites show accelerated ageing behavior because of enhanced dislocation density at the fiber/matrix interface resulting from thermal expansion mismatch between ceramic fiber and the metal matrix. The accelerated ageing of aluminium alloy composites either from dislocation density or the residual stress, as a result of thermal expansion mismatch is dependent on the size of whisker and particulate. Investigations have also been made on the effect of volume fraction of particulate on the ageing behavior of aluminium alloys. The present investigation is concerned with characterization of age-hardening behavior of an Al-Si-Cu-Mg(AA 336) alloy alumino-silicate discontinuous fiber-reinforced composites (referred to as aluminium MMCs in the present text) being developed for automotive pistons. An effort is made to study the effect of volume fraction of the reinforcement on age-hardening behavior of this composite.

  12. Incremental forming of aluminium alloys in cryogenic environment

    NASA Astrophysics Data System (ADS)

    Vanhove, Hans; Mohammadi, Amirahmad; Duflou, Joost R.

    2016-10-01

    Incremental Sheet Forming processes suffer from stringent forming limits, restricting the range of producible geometries. Through in-process cooling of the sheet to cryogenic level, this paper explores the potential of altering material properties benefiting the formability and residual hardness of different aluminium alloys. Global cooling of aluminium sheets with liquid nitrogen and dry ice allows to reach temperatures of 78K and 193K respectively. Extended with experiments at room temperature (293K), these tests form a base for comparison of surface quality, formability and residual hardness. As an aluminium alloy commonly used for its high strength to weight ratio, but suffering from limited formability compared to draw-quality steels, AA5083-H111 is of interest for cryogenic treatment. AA1050-H24 is included in the test campaign as a base for commercially pure aluminium.

  13. Constitutive modelling of aluminium alloy sheet at warm forming temperatures

    NASA Astrophysics Data System (ADS)

    Kurukuri, S.; Worswick, M. J.; Winkler, S.

    2016-08-01

    The formability of aluminium alloy sheet can be greatly improved by warm forming. However predicting constitutive behaviour under warm forming conditions is a challenge for aluminium alloys due to strong, coupled temperature- and rate-sensitivity. In this work, uniaxial tensile characterization of 0.5 mm thick fully annealed aluminium alloy brazing sheet, widely used in the fabrication of automotive heat exchanger components, is performed at various temperatures (25 to 250 °C) and strain rates (0.002 and 0.02 s-1). In order to capture the observed rate- and temperature-dependent work hardening behaviour, a phenomenological extended-Nadai model and the physically based (i) Bergstrom and (ii) Nes models are considered and compared. It is demonstrated that the Nes model is able to accurately describe the flow stress of AA3003 sheet at different temperatures, strain rates and instantaneous strain rate jumps.

  14. Microstructural and Mechanical Characterization of Zr Modified 2014 Aluminium Alloy

    DTIC Science & Technology

    2007-11-02

    heated using an induction furnace; the temperature stabilisation time was 6 min. -The gauge section of samples was a solid cylinder with a length (L) of...torsion tests - Fatigue tests -Fracture observations Introduction -Aluminium sheets require a good attitude to the cold metal forming. -Al-Cu-Mg alloys...precipitation occurring during hot deformation or heat treatment Introduction -The precipitation sequence for 2014 Al alloys has been extensively

  15. Fatigue in a heat treatable high silicon containing aluminium alloy

    NASA Astrophysics Data System (ADS)

    González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael

    2017-05-01

    The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

  16. The Corrosion Resistance and Paint Adhesion Properties of Chromate Conversion Coatings on Aluminium and Its Alloys

    DTIC Science & Technology

    1976-05-01

    aluminium and its alloys has been evaluated with respect to both corrosion resistance of, and paint adhesion to, the chromate films. The process involves...The findings in this Report will be used as the basis for a Defence Standard for chromate conversion coatings for aluminium and aluminium alloys...3 PROPRIETARY CHROMATE CONVERSION COATINGS FOR ALUMINIUM 17 4 PAINT ADHESION 19 5 DISCUSSION 21 6 CONCLUSIONS 24 Acknowledgments 25 Appendix A

  17. Recycling of aluminium scrap for secondary Al-Si alloys.

    PubMed

    Velasco, Eulogio; Nino, Jose

    2011-07-01

    An increasing amount of recycled aluminium is going into the production of aluminium alloy used for automotive applications. In these applications, it is necessary to control and remove alloy impurities and inclusions. Cleaning and fluxing processes are widely used during processing of the alloys for removal of inclusions, hydrogen and excess of magnesium. These processes use salt fluxes based in the system NaCl-KCl, injection of chlorine or mixture of chlorine with an inert gas. The new systems include a graphite wand and a circulation device to force convection in the melt and permit the bubbling and dispersion of reactive and cleaning agents. This paper discusses the recycling of aluminium alloys in rotary and reverberatory industrial furnaces. It focuses on the removal of magnesium during the melting process. In rotary furnaces, the magnesium lost is mainly due to the oxidation process at high temperatures. The magnesium removal is carried out by the reaction between chlorine and magnesium, with its efficiency associated to kinetic factors such as concentration of magnesium, mixing, and temperature. These factors are also related to emissions generated during the demagging process. Improvements in the metallic yield can be reached in rotary furnaces if the process starts with a proper salt, with limits of addition, and avoiding long holding times. To improve throughput in reverberatories, start the charging with high magnesium content material and inject chlorine gas if the molten metal is at the right temperature. Removal of magnesium through modern technologies can be efficiently performed to prevent environmental problems.

  18. Monitoring Precipitation during Rapid Quenching of Aluminium Alloys by Calorimetric Reheating Experiments

    NASA Astrophysics Data System (ADS)

    Kessler, Olaf; Zohrabyan, Davit; Milkereit, Benjamin; Schick, Christoph

    Several age hardening aluminium alloys, like high alloyed 2XXX, 6XXX and 7XXX alloys require high critical quenching rates of some 100 K/s from solution annealing to suppress premature precipitation and achieve maximum strength after aging. Knowledge of the precipitation behaviour during quenching is crucial for the design of quenching processes of aluminium alloys. For monitoring the precipitation behaviour during moderate quenching, a calorimetric method (0.01 to 5 K/s) has already been successfully developed. New Differential Fast Scanning Calorimeters (DFSC, up to some 106 K/s) allow rapid quenching of aluminium alloys, but due to weak precipitation reactions the quenching results can hardly be evaluated. Hence, a new method has been developed, to monitor precipitation during rapid quenching of aluminium alloys by calorimetric reheating experiments. Quenching and reheating experiments of high alloyed, quench sensitive aluminium alloys, like 7049A will be presented.

  19. Results of the Experiment: Welding of Aluminium Alloy in Microgravity

    NASA Astrophysics Data System (ADS)

    Ferretti, S.; Amadori, K.; Boccalatte, A.; Alessandrini, M.; Freddi, A.; Persiani, F.; Poli, G.

    2002-01-01

    An experiment on "dendritic growth in aluminium alloy welding" was performed by the UNIBO team during the 3rd Student Parabolic Flight Campaign and the 30th Professional Parabolic Flight Campaign organised by ESA. Its purpose was to achieve a better understanding of crystal growth during tungsten inert gas (TIG) welding of an aluminium alloy to define the main parameters affecting the process under microgravity condition. The experiment had 4 phases : The paper discusses different aspects of the research, paying particularly attention not only to the influence of gravity, but also to other factors influencing welding microstructure, such as the Marangoni effect and the thermal transfer from the electrode to the material. The paper conclude the dissertation of the results offering new perspectives for welding studies and proposing a new approach to the scientific community to investigate this materials processes for manufacturing.

  20. Research progress of aluminium alloy endplates for PEMFCs

    NASA Astrophysics Data System (ADS)

    Fu, Yu; Hou, Ming; Yan, Xiqiang; Hou, Junbo; Luo, Xiaokuan; Shao, Zhigang; Yi, Baolian

    The endplate is a crucial component in a proton exchange membrane fuel cell (PEMFC) stack. It can provide the necessary rigidity and strength for the stack. An aluminium alloy is one of the ideal materials for PEMFC endplates because of its low density and high rigidity. But it does not meet the requirements of corrosion resistance and electrical insulation in PEMFC environments. In this work, methods of sealing treatments and the conditions of aluminium alloy anodization were investigated. Corrosion resistances of the samples prepared by different technologies were evaluated in simulated PEMFC environments. The results showed that the corrosion resistance of the samples sealed by epoxy resin was greatly improved compared with those sealed in boiling water, and the samples anodized at a constant current density performed better than those anodized at a constant voltage. By insulation measurements, all of the samples showed good electrical insulation. The aluminium alloy endplate anodized at a constant current density and sealed with thermosetting bisphenol-A epoxy resin exhibited promising potential for practical applications by assembling it in a PEMFC stack and applying a life test.

  1. Carbon treated commercial aluminium alloys as anodes for aluminium-air batteries in sodium chloride electrolyte

    NASA Astrophysics Data System (ADS)

    Pino, M.; Herranz, D.; Chacón, J.; Fatás, E.; Ocón, P.

    2016-09-01

    An easy treatment based in carbon layer deposition into aluminium alloys is presented to enhance the performance of Al-air primary batteries with neutral pH electrolyte. The jellification of aluminate in the anode surface is described and avoided by the carbon covering. Treated commercial Al alloys namely Al1085 and Al7475 are tested as anodes achieving specific capacities above 1.2 Ah g-1vs 0.5 Ah g-1 without carbon covering. The influence of the binder proportion in the treatment as well as different carbonaceous materials, Carbon Black, Graphene and Pyrolytic Graphite are evaluated as candidates for the covering. Current densities of 1-10 mA cm-2 are measured and the influence of the alloy explored. A final battery design of 4 cells in series is presented for discharges with a voltage plateau of 2 V and 1 Wh g-1 energy density.

  2. On the Critical Technological Issues of Friction Stir Welding T-Joints of Dissimilar Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Astarita, A.; Squillace, A.; Scala, A.; Prisco, A.

    2012-08-01

    In this article, friction stir welded T-joints of innovative dissimilar aluminum alloys have been produced and tested with the aim to investigate the feasibility of using this joining technique, in this configuration, in the aerospace field with the final aim to save weight. The introduction of both this new welding technique and innovative alloys, such as AA 2198 and AA 6056, could allow making lighter and stronger structures. Some experiments, carried out previously, have shown that the fixturing device, the tool geometry, and the tilt angle play a significant role in the joint soundness. A wide experimental characterization has been carried out on FSW T-joints of AA 6056 T4 extrudes to AA 2198 T3 rolled plates. The results attained allow to put in evidence some critical issues on the investigated configuration and can be considered as a further acquired knowledge in the understanding and the design of friction stir processes.

  3. Diffusion bonding of aluminium alloy, 8090

    SciTech Connect

    Sunwoo, A. )

    1994-08-15

    Ability to diffusion bond aluminum (Al) alloys, in particular superplastic aluminum alloys, will complete the technology-base that is strongly needed to enhance the use of superplastic forming (SPF) technology. Diffusion bonding (DB) is an attractive manufacturing option for applications where the preservation of the base metal microstructure and, in turn, mechanical properties is important in the bond area. As the technology moves from the laboratory to production, the DB process has to be production-feasible and cost-effective. At the Lawrence Livermore National Laboratory, the DB study of SPF Al alloys has been initiated. This paper describes the effect of surface chemistry on the DB properties of the Al alloy, 8090 (2.4Li-1.18Cu-0.57Mg-0.14Zr-Al). The integrity of the diffusion bonds was evaluated for both interlayered and bare surfaces. Two interlayer elements, copper (Cu) and zinc (Zn), were compared. Although the eutectic temperature of Al-Cu is 548 C, a thin Cu layer in contact with 8090 has been shown to lower its eutectic temperature to [approximately]521 C. In 8090, Cu is one of the primary alloying elements but has a limited solubility in Al at the bonding temperature. Zinc, on the other hand, forms a considerably lower eutectic (380 C) with Al and is highly soluble in Al. The diffusivity of Zn in Al is much faster than that of Cu, but Zn forms a more thermodynamically stable oxide. These subtle metallurgical differences will affect the transient liquid phase (TLP) formation at the interface, which will subsequently influence the bond quality.

  4. Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite

    SciTech Connect

    Sayuti, M.; Sulaiman, S.; Baharudin, B. T. H. T.; Arifin, M. K. A.; Suraya, S.; Vijayaram, T. R.

    2011-01-17

    This paper discusses the mechanical properties of Titanium Carbide (TiC) particulate reinforced aluminium-silicon alloy matrix composite. TiC particulate reinforced LM6 alloy matrix composites were fabricated by carbon dioxide sand molding process with different particulate weight fraction. Tensile strength, hardness and microstructure studies were conducted to determine the maximum load, tensile strength, modulus of elasticity and fracture surface analysis have been performed to characterize the morphological aspects of the test samples after tensile testing. Hardness values are measured for the TiC reinforced LM6 alloy composites and it has been found that it gradually increases with increased addition of the reinforcement phase. The tensile strength of the composites increased with the increase percentage of TiC particulate.

  5. Nanostructural hierarchy increases the strength of aluminium alloys.

    PubMed

    Liddicoat, Peter V; Liao, Xiao-Zhou; Zhao, Yonghao; Zhu, Yuntian; Murashkin, Maxim Y; Lavernia, Enrique J; Valiev, Ruslan Z; Ringer, Simon P

    2010-09-07

    Increasing the strength of metallic alloys while maintaining formability is an interesting challenge for enabling new generations of lightweight structures and technologies. In this paper, we engineer aluminium alloys to contain a hierarchy of nanostructures and possess mechanical properties that expand known performance boundaries-an aerospace-grade 7075 alloy exhibits a yield strength and uniform elongation approaching 1 GPa and 5%, respectively. The nanostructural architecture was observed using novel high-resolution microscopy techniques and comprises a solid solution, free of precipitation, featuring (i) a high density of dislocations, (ii) subnanometre intragranular solute clusters, (iii) two geometries of nanometre-scale intergranular solute structures and (iv) grain sizes tens of nanometres in diameter. Our results demonstrate that this novel architecture offers a design pathway towards a new generation of super-strong materials with new regimes of property-performance space.

  6. Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite

    NASA Astrophysics Data System (ADS)

    Sayuti, M.; Sulaiman, S.; Baharudin, B. T. H. T.; Arifin, M. K. A.; Suraya, S.; Vijayaram, T. R.

    2011-01-01

    This paper discusses the mechanical properties of Titanium Carbide (TiC) particulate reinforced aluminium-silicon alloy matrix composite. TiC particulate reinforced LM6 alloy matrix composites were fabricated by carbon dioxide sand molding process with different particulate weight fraction. Tensile strength, hardness and microstructure studies were conducted to determine the maximum load, tensile strength, modulus of elasticity and fracture surface analysis have been performed to characterize the morphological aspects of the test samples after tensile testing. Hardness values are measured for the TiC reinforced LM6 alloy composites and it has been found that it gradually increases with increased addition of the reinforcement phase. The tensile strength of the composites increased with the increase percentage of TiC particulate.

  7. Numerical Modelling of Drawbeads for Forming of Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Joshi, Y.; Christiansen, P.; Masters, I.; Bay, N.; Dashwood, R.

    2016-08-01

    The drawbeads in stamping tools are usually designed based on experience from the forming of steel. However, aluminium alloys display different forming behaviour to steels, which is not reflected in the drawbead design for tools used for stamping aluminium. This paper presents experimental results from different semi-circular drawbead geometries commonly encountered in automotive dies and compares them to those obtained from Stoughton's analytical drawbead model and the 2D plane strain drawbead model set up using LS-DYNA. The study was conducted on lubricated NG5754 strips. The results presented are in terms of drawbead restraining force versus strip displacement, as a function of drawbead depth. The FE drawbead model agrees well with the experiments whereas the analytical model overpredicted the drawbead forces.

  8. 3D printing of high-strength aluminium alloys.

    PubMed

    Martin, John H; Yahata, Brennan D; Hundley, Jacob M; Mayer, Justin A; Schaedler, Tobias A; Pollock, Tresa M

    2017-09-20

    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

  9. Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

    NASA Technical Reports Server (NTRS)

    Reed, R. P.

    1972-01-01

    The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

  10. The fracture of boron fibre-reinforced 6061 aluminium alloy

    NASA Technical Reports Server (NTRS)

    Wright, M. A.; Welch, D.; Jollay, J.

    1979-01-01

    The fracture of 6061 aluminium alloy reinforced with unidirectional and cross-plied 0/90 deg, 0/90/+ or - 45 deg boron fibres has been investigated. The results have been described in terms of a critical stress intensity, K(Q). Critical stress intensity factors were obtained by substituting the failure stress and the initial crack length into the appropriate expression for K(Q). Values were obtained that depended on the dimensions of the specimens. It was therefore concluded that, for the size of specimen tested, the values of K(Q) did not reflect any basic materials property.

  11. Deviatoric Response of AN Armour-Grade Aluminium Alloy

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, G. J.; Hazell, P. J.; Millett, J.; Bourne, N. K.

    2009-12-01

    Aluminium alloys such as 5083 H32 are established light-weight armour materials. As such, the shock response of these materials is of great importance. The shear strength of a material under shock loading provides an insight into its ballistic performance. In this investigation embedded manganin stress gauges have been employed to measure both the longitudinal and lateral components of stress during plate-impact experiments over a range of impact stresses. In turn, these results were used to determine the shear strength and to investigate the time dependence of lateral stress behind the shock front to give an indication of material response.

  12. Foaming of aluminium-silicon alloy using concentrated solar energy

    SciTech Connect

    Cambronero, L.E.G.; Ruiz-Roman, J.M.; Canadas, I.; Martinez, D.

    2010-06-15

    Solar energy is used for the work reported here as a nonconventional heating system to produce aluminium foam from Al-Si alloy precursors produced by powder metallurgy. A commercial precursor in cylindrical bars enclosed in a stainless-steel mould was heated under concentrated solar radiation in a solar furnace with varied heating conditions (heating rate, time, and temperature). Concentrated solar energy close to 300 W/cm{sup 2} on the mould is high enough to achieve complete foaming after heating for only 200 s. Under these conditions, the density and pore distribution in the foam change depending on the solar heating parameters and mould design. (author)

  13. High rate constitutive modeling of aluminium alloy tube

    NASA Astrophysics Data System (ADS)

    Salisbury, C. P.; Worswick, M. J.; Mayer, R.

    2006-08-01

    As the need for fuel efficient automobiles increases, car designers are investigating light-weight materials for automotive bodies that will reduce the overall automobile weight. Aluminium alloy tube is a desirable material to use in automotive bodies due to its light weight. However, aluminium suffers from lower formability than steel and its energy absorption ability in a crash event after a forming operation is largely unknown. As part of a larger study on the relationship between crashworthiness and forming processes, constitutive models for 3mm AA5754 aluminium tube were developed. A nominal strain rate of 100/s is often used to characterize overall automobile crash events, whereas strain rates on the order of 1000/s can occur locally. Therefore, tests were performed at quasi-static rates using an Instron test fixture and at strain rates of 500/s to 1500/s using a tensile split Hopkinson bar. High rate testing was then conducted at rates of 500/s, 1000/s and 1500/s at 21circC, 150circC and 300circC. The generated data was then used to determine the constitutive parameters for the Johnson-Cook and Zerilli-Armstrong material models.

  14. Electromagnetic forming of aluminium alloy sheet

    NASA Astrophysics Data System (ADS)

    Oliveira, D. A.; Worswick, M.

    2003-09-01

    A numerical method for modeling the high rate deformation and impact that occurs during the electromagnetic forming process is presented with supporting experimental data, used to validate the predictions. The numerical model employs “loose" two-way coupling of the electromagnetic analysis with the elastic-plastic structural analysis. An electromagnetic finite element code is used to model the time varying currents that are discharged through the coil in order to obtain the transient magnetic forces that are imparted to the workpiece. The body forces generated by electromagnetic induction are then used as the loading condition to model the high rate deformation of the workpiece using an explicit dynamic finite element code. A series of high rate electromagnetic forming experiments are performed on 1 and 1.6 mm AA5754 and 1 mm AA5182 aluminum alloy sheet. The experiments consider free forming, while also serving as a basis to validate the predictive capability of the numerical models. The experiments exhibited high rate formability limits that were similar to conventional quasistatic forming limits. The numerical model accurately predicted the final geometry of the samples as well as the measured strain distributions.

  15. Frictional conditions between alloy AA6060 aluminium and tool steel

    SciTech Connect

    Wideroee, Fredrik; Welo, Torgeir

    2011-05-04

    The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples to measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.

  16. Frictional conditions between alloy AA6060 aluminium and tool steel

    NASA Astrophysics Data System (ADS)

    Widerøe, Fredrik; Welo, Torgeir

    2011-05-01

    The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples to measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.

  17. Thermoelectric power in low-density interstitial-free iron-aluminium alloys

    NASA Astrophysics Data System (ADS)

    Rana, Radhakanta; Liu, Cheng

    2013-09-01

    Thermoelectric power (TEP) studies on low-density interstitial-free iron-aluminium alloys reveal that the TEP decreases with increase in the aluminium content on account of the introduction of lattice dispersion centres. The TEP coefficients, determined from the Nordheim-Gorter law, for 6.8 and 8.1 wt.% aluminium additions to α-iron are found to be higher than values reported in previous literature for small aluminium additions. The grain size has a very weak effect on the TEP of these alloys.

  18. The Effect of Alloy Content on the Grain Refinement of Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Easton, M. A.; StJohn, D. H.

    A recent model that predicts the effect of solute content on grain size was shown to predict the effect of titanium additions on the grain size of pure aluminium and an AlSi7Mg0.3 alloy. The model assumes that nucleation on substrates is facilitated by constitutional undercooling in front of a growing grain. To determine how generally applicable the model is to a broad range of aluminium alloys, titanium additions were made to five wrought alloys containing the same level of TiB2. It was found that the grain size obtained is a function of the reciprocal of mc0(k-1), the growth restriction factor, and that there is a lower limit to the grain size that can be achieved for the casting conditions used in the experiments. It was also found that at least stoichiometric levels of titanium are required for TiB2 particles to be effective nucleants.

  19. Performance of commercial aluminium alloys as anodes in gelled electrolyte aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Pino, M.; Chacón, J.; Fatás, E.; Ocón, P.

    2015-12-01

    The evaluation of commercial aluminium alloys, namely, Al2024, Al7475 and Al1085, for Al-air batteries is performed. Pure Al cladded Al2024 and Al7475 are also evaluated. Current rates from 0.8 mA cm-2 to 8.6 mA cm-2 are measured in a gel Al-air cell composed of the commercial alloy sample, a commercial air-cathode and an easily synthesizable gelled alkaline electrolyte. The influence of the alloying elements and the addition to the electrolyte of ZnO and ZnCl2, as corrosion inhibitors is studied and analysed via EDX/SEM. Specific capacities of up to 426 mAh/g are obtained with notably flat potential discharges of 1.3-1.4 V. The competition between self-corrosion and oxidation reactions is also discussed, as well as the influence of the current applied on that process. Al7475 is determined to have the best behaviour as anode in Al-air primary batteries, and cladding process is found to be an extra protection against corrosion at low current discharges. Conversely, Al1085 provided worse results because of an unfavourable metallic composition.

  20. The influence of alloy composition on residual stresses in heat treated aluminium alloys

    SciTech Connect

    Robinson, J.S.; Redington, W.

    2015-07-15

    The as quenched properties of eight different heat treatable aluminium alloys are related to residual stress magnitudes with the objective being to establish if there is a relationship between the residual stress and the as quenched alloy hardness and strength. Near surface residual stresses were assessed with X-ray diffraction using both the established sin{sup 2}ψ method and the more recent cos α technique. Through thickness residual stresses were also characterised using neutron diffraction. The alloys were chosen to encompass a wide range of strengths. The low to medium strength alloys were 6060 and 6082, medium to high strength 2618A, 2014A, 7075, 7010 and two variants of 7449, while the very high strength alloy was the powder metallurgy alloy N707. To assess the as quenched strength, dynamic hardness and tensile properties were determined from samples tested immediately after quenching to minimise the influence of precipitation hardening by natural aging. In addition, hot hardness measurements were made in situ on samples cooled to simulate quench paths. Within the experimental constraints of the investigation, the distribution of residual stress through the thickness was found to follow the same pattern for all the alloys investigated, varying from tensile in the interior to surface compression. The influence of alloy strength was manifested as a change in the observed residual stress magnitudes, and surface residual stresses were found to vary linearly with as quenched hardness and strength. - Highlights: • As quenched aluminium alloys contain high magnitude residual stresses. • Surface is compressive balance by a tensile core. • As quenched surface residual stress is linear function of alloy strength. • In situ hot hardness demonstrates rapid change in intrinsic hardness during rapid cooling.

  1. Quantitative prediction of solute strengthening in aluminium alloys

    NASA Astrophysics Data System (ADS)

    Leyson, Gerard Paul M.; Curtin, William A.; Hector, Louis G.; Woodward, Christopher F.

    2010-09-01

    Despite significant advances in computational materials science, a quantitative, parameter-free prediction of the mechanical properties of alloys has been difficult to achieve from first principles. Here, we present a new analytic theory that, with input from first-principles calculations, is able to predict the strengthening of aluminium by substitutional solute atoms. Solute-dislocation interaction energies in and around the dislocation core are first calculated using density functional theory and a flexible-boundary-condition method. An analytic model for the strength, or stress to move a dislocation, owing to the random field of solutes, is then presented. The theory, which has no adjustable parameters and is extendable to other metallic alloys, predicts both the energy barriers to dislocation motion and the zero-temperature flow stress, allowing for predictions of finite-temperature flow stresses. Quantitative comparisons with experimental flow stresses at temperature T=78K are made for Al-X alloys (X=Mg, Si, Cu, Cr) and good agreement is obtained.

  2. Effects of progressive solution treatment on microstructure and property of the aluminium alloy electrical round rod

    NASA Astrophysics Data System (ADS)

    Hu, Xiejun; Zhang, Renguo; Zhang, Xiaoyan; Lin, Tingyi; Zhang, Junjie; Yan, Jun

    2017-06-01

    This paper aims to research the effects of progressive solution treatment on property of aluminium alloy electrical round rod, we mainly research the influences of different temperature on tensile strength and electrical conductivity of the aluminium alloy electrician round rod. The component and phase constitution of the aluminium alloy was analysed by means of OLYMPUSPMG-3 horizontal metallurgical microscope, SUPRA40 scanning electron microscope, APOLLO-10Xenergy spectrometer, tensile strength and conductivity of aluminium alloy electrical round rod under various progressive solution treatment. The results show that: comprehensive performance of specimen is optimal by means of scheme(350 °C×1h+510°C×6h), the conductivity is 56.6%IACS and the tensile strength is 103MPa.

  3. Microstructure and properties of hot compacted powders of aluminium alloys.

    PubMed

    Lityńska-Dobrzyńska, L; Dutkiewicz, J; Maziarz, W; Kanciruk, A

    2009-11-01

    Atomized 6061 aluminium alloy powders with and without the addition of 2 wt% Zr were milled for 80 h in a planetary ball mill and hot pressed in vacuum. The milled powders showed microhardness of about 170 HV, which increased after hot pressing up to 260 HV and up to 280 HV for powders without and with the Zr additions, respectively. Compression tests showed the high yield stress of 300 MPa obtained for the hot-pressed sample produced from the initial powders compared with ultimate compression strength of above 800 MPa for that of the milled sample and slightly higher for that with Zr additions. The effect of hot pressing on the structure of powders was investigated using a conventional analytical and high-resolution electron microscopy and high angle annular dark-field scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis. The samples of initial powders hot pressed in vacuum showed a cell structure with particles of the Mg(2)Si and AlFeSi phases in intercell areas. In the milled and hot-pressed sample, the homogeneous structure of small grains of size below 200 nm was observed. The AlFeSi and Mg(2)Si particles with size 20-100 nm were uniformly distributed as well as the Zr rich particles in the Zr containing alloy. The Zr-rich particles containing up to 80 at% Zr were identified as a metastable fcc cubic phase with lattice parameter a= 0.48 nm.

  4. Modelling of Local Necking and Fracture in Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Achani, D.; Eriksson, M.; Hopperstad, O. S.; Lademo, O.-G.

    2007-05-01

    Non-linear Finite Element simulations are extensively used in forming and crashworthiness studies of automotive components and structures in which fracture need to be controlled. For thin-walled ductile materials, the fracture-related phenomena that must be properly represented are thinning instability, ductile fracture and through-thickness shear instability. Proper representation of the fracture process relies on the accuracy of constitutive and fracture models and their parameters that need to be calibrated through well defined experiments. The present study focuses on local necking and fracture which is of high industrial importance, and uses a phenomenological criterion for modelling fracture in aluminium alloys. As an accurate description of plastic anisotropy is important, advanced phenomenological constitutive equations based on the yield criterion YLD2000/YLD2003 are used. Uniaxial tensile tests and disc compression tests are performed for identification of the constitutive model parameters. Ductile fracture is described by the Cockcroft-Latham fracture criterion and an in-plane shear tests is performed to identify the fracture parameter. The reason is that in a well designed in-plane shear test no thinning instability should occur and it thus gives more direct information about the phenomenon of ductile fracture. Numerical simulations have been performed using a user-defined material model implemented in the general-purpose non-linear FE code LS-DYNA. The applicability of the model is demonstrated by correlating the predicted and experimental response in the in-plane shear tests and additional plane strain tension tests.

  5. New developments on optimizing properties of high-Zn aluminium cast alloys

    NASA Astrophysics Data System (ADS)

    Krajewski, W. K.; Buras, J.; Krajewski, P. K.; Greer, A. L.; Schumacher, P.; Haberl, K.

    2016-07-01

    Foundry alloys with Al-based matrices have a wide range of uses in today's global economy and there is a high demand for castings of Al alloys, including Al-Zn alloys. In this paper, investigations on the grain refinement of high-Zn aluminium cast alloys are presented. Aluminium alloys with relatively high zinc content have a tendency to be coarse-grained, especially in the case of castings with low cooling rates such as are found in sand moulds. The coarse-grained structure degrades the plasticity, specifically the elongation. Therefore, for aluminium alloys of high (10-30 wt.%) zinc content, inoculation is attractive, aiming to break up the primary dendrites of the a-phase solid solution of zinc in aluminium. Such dendrites are the principal microstructural component in these alloys. On the other hand, a finer grain structure usually reduces the damping (e.g. as measured by attenuation of ultrasound) in these alloys. In the present investigations, a binary sand-cast Al-20 wt.% Zn alloy was inoculated with different additions of AlTi3C0.15 (TiCAl) and ZnTi-based master alloys. The sand-cast samples were subjected to mechanical-property measurements (tensile strength and elongation), image analysis to determine grain size, and measurements of the attenuation of 1 MHz ultrasound. It is found that both of the master alloys used cause significant refinement of the a-AlZn primary dendrites and change their morphology from linear-branched to semi-globular, increase the elongation by about 40%, and decrease the attenuation coefficient by about 25% in comparison with the initial alloy without inoculation.

  6. High strain rate superplasticity of AlN particulate reinforced aluminium alloy composites

    SciTech Connect

    Imai, T. ); L'Esperance, G.; Hong, B.D. )

    1994-08-01

    Ceramic whisker or particulate reinforced aluminium alloy composites have a great potential for automobile engineering components, aerospace structures, semi-conductor packaging and so on, because of the composites ability to exhibit a high specific elastic modulus and specific tensile strength, excellent wear resistance and heat resistance, low thermal expansion and good dimensional stability. A serious problem involving practical application of ceramic whisker or particulate reinforced aluminium alloy composites is due to the low tensile ductility, fracture toughness at room temperature and, also, their hardness qualities that make it difficult to deform by conventional forming processing and machining by ordinary tools. It has been found, however, that aluminium alloy composites reinforced by SiC or Si[sub 3]N[sub 4] whiskers or particulates produce superplasticity at a high strain rate of about 0.1s[sup [minus]1]. Superplastic deformation mechanisms of the ceramic whisker or particulate reinforced aluminium alloy composites are fine grain boundary sliding, interfacial sliding at a liquid phase and dynamic recrystallization. An AlN particulate reinforced aluminium alloy composite exhibits a high elastic modulus and a high thermal conductivity, and their thermal expansion is similar to silicon in that the AlN particulate reinforced aluminum alloy composite is expected to apply to semi-conductor packaging in the aerospace structure. In addition, if the composite could produce superplasticity at high strain rates, the market of aerospace application for superplastic composites could be expanded. The purpose of this study is to make clear if an AlN particulate reinforced aluminium alloy composite can produce superplasticity at high strain rate and the superplastic characteristics.

  7. Void growth in high strength aluminium alloy single crystals: a CPFEM based study

    NASA Astrophysics Data System (ADS)

    Asim, Umair; Siddiq, M. Amir; Demiral, Murat

    2017-04-01

    High strength aluminium alloys that are produced through forming and joining processes are widely used in aerospace components. The ductile failure in these metals occurs due to the evolution and accumulation of microscopic defects, such as microvoids and shear bands. The present work investigates the underlying physical mechanisms during ductile failure by performing a rigorous, fully-validated, three-dimensional crystal plasticity, finite element study with aluminium alloy single crystals. Representative volume element (RVE) based simulations of single crystalline aluminium alloys (AA-5xxx) with different void geometries and orientations have been performed. Both local and nonlocal crystal plasticity constitutive models have been implemented in a finite element framework and are used to seek new insights into the interrelationships among void growth, initial porosity, initial void size, plastic anisotropy, and local/nonlocal size effects.

  8. Self-Pierce Riveting of Three Aluminium Alloy and Mild Steel Sheets

    SciTech Connect

    Mori, K.; Abe, Y.; Sakai, S.; Kato, T.

    2010-06-15

    Three aluminium alloy and steel sheets were joined with a self-piercing rivet. Self-pierce riveting has the function of joining steel and aluminium alloys having very different melting points due to plastic joining. The requisites for joining the three sheets are the driving of the rivet leg through the middle sheet, the flaring of the rivet leg in the lower sheet and the prevention of the fracture of the lower sheet. The joinability for various combinations of the three sheets was determined. When the rivet leg is small, no driving through the middle sheet occurs, the lower sheet ruptures for a large rivet leg. In addition, 980 MPa high strength steel, mild steel and aluminium alloy sheets were joined by the self-pierce riveting.

  9. Self-Pierce Riveting of Three Aluminium Alloy and Mild Steel Sheets

    NASA Astrophysics Data System (ADS)

    Mori, K.; Abe, Y.; Kato, T.; Sakai, S.

    2010-06-01

    Three aluminium alloy and steel sheets were joined with a self-piercing rivet. Self-pierce riveting has the function of joining steel and aluminium alloys having very different melting points due to plastic joining. The requisites for joining the three sheets are the driving of the rivet leg through the middle sheet, the flaring of the rivet leg in the lower sheet and the prevention of the fracture of the lower sheet. The joinability for various combinations of the three sheets was determined. When the rivet leg is small, no driving through the middle sheet occurs, the lower sheet ruptures for a large rivet leg. In addition, 980 MPa high strength steel, mild steel and aluminium alloy sheets were joined by the self-pierce riveting.

  10. Silica mesoporous thin films as containers for benzotriazole for corrosion protection of 2024 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Recloux, Isaline; Mouanga, Maixent; Druart, Marie-Eve; Paint, Yoann; Olivier, Marie-Georges

    2015-08-01

    This work contributes to the development of a new environmentally friendly alternative pretreatment for 2024 aluminium alloys to replace hexavalent chromium based conversion layers in the aeronautical field. A silica mesoporous thin film, synthesized through the evaporation induced self-assembly process, was doped with benzotriazole to obtain active corrosion protection. Inhibitor loading contents were correlated with pore characteristics. The release kinetics was studied as function of pH. The application of the doped mesoporous film on 2024 aluminium alloy revealed a slowing down of corrosion processes, demonstrating its potential as an active inhibitor storage layer.

  11. Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part II corrosion performance

    NASA Astrophysics Data System (ADS)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-11-01

    Surface treatment of aluminium alloys using steam with oxidative chemistries, namely KMnO4 and HNO3 resulted in accelerated growth of oxide on aluminium alloys. Detailed investigation of the corrosion performance of the treated surfaces was carried out using potentiodynamic polarisation and standard industrial test methods such as acetic acid salt spray (AASS) and filiform corrosion on commercial AA6060 alloy. Barrier properties of the film including adhesion were evaluated using tape test under wet and dry conditions. Electrochemical results showed reduced cathodic and anodic activity, while the protection provided by steam treatment with HNO3 was a function of the concentration of NO3- ions. The coating generated by inclusion of KMnO4 showed highest resistance to filiform corrosion. Overall, the performance of the steam treated surfaces under filiform corrosion and AASS test was a result of the local coverage of the alloy microstructure resulting from steam containing with KMnO4 and HNO3.

  12. Evaluation Of Four Welding Arc Processes Applied To 6061 Aluminium Alloy

    SciTech Connect

    Benoit, A.; Paillard, P.; Baudin, T.; Jobez, S.; Castagne, J.-F.

    2011-01-17

    At a time when greenhouse gas emissions must be reduced, the use of the aluminium alloys is expanding, in particular in the transportation industry. In order to extend the possibilities of aluminium assembly design, new Metal Inert Gas (MIG) welding processes have been conceived. They work at lower temperatures than usual arc processes (classic MIG or Tungsten Inert Gas). This study compares four arc welding processes, applied to the 6061 aluminium alloy. These four weld processes have been studied through the metallurgical analysis of the weld beads. Metallography, micro-hardness testings, X Ray radiography have been carried out on the produced weld beads. The processes are classified according to the quality of the beads like geometry of beads, size of the heat affected zone and presence of defects.

  13. Radiation resistance and parameters of activation of aluminium-magnesium-scandium and aluminium-magnesium-vanadium alloys under neutron irradiation

    NASA Astrophysics Data System (ADS)

    Ivanov, L. I.; Ivanov, V. V.; Lazorenko, V. M.; Platov, Yu. M.; Tovtin, V. I.; Toropova, L. S.

    1992-09-01

    Alloys Al2.24Mg0.23Sc0.04Zr, Al2.24Mg0.12Sc0.04Zr, and Al2.24Mg0.05V (at.)) annealed at 150°C and 400°C were irradiated ≈70 and ≈150°C in the SM-2 reactor. The maximum neutron fluence was 4.7×1024 m-2 (E > 0.1 MeV). The tensile tests were carried out in the temperature range 20 to 350°C. Alloy Al2.24Mg0.23Sc0.04Zr annealed at 400°C and alloy Al2.24Mg0.12Sc0.04Zr annealed at 150°C at all test temperature, retained good mechanical properties after irradiation. The mechanisms for the radiation resistance of aluminiumscandium and aluminiummagnesiumscandium alloys are discussed. Calculations of induced radioactivity and its decay behaviour after shutdown in aluminium and Al2.24Mg(0.12-0.23)Sc alloys were carried out. Composition of the radionuclides in these materials after irradiation in the SM-2 reactor were also determined using a gamma-spectroscopy technique.

  14. Property enhancement by grain refinement of zinc-aluminium foundry alloys

    NASA Astrophysics Data System (ADS)

    Krajewski, W. K.; Greer, A. L.; Piwowarski, G.; Krajewski, P. K.

    2016-03-01

    Development of cast alloys with good mechanical properties and involving less energy consumption during their melting is one of the key demands of today's industry. Zinc foundry alloys of high and medium Al content, i.e. Zn-(15-30) wt.% Al and Zn-(8-12) wt.% Al, can satisfy these requirements. The present paper summarizes the work [1-9] on improving properties of sand-cast ZnAl10 (Zn-10 wt.% Al) and ZnAl25 (Zn-25 wt. % Al) alloys by melt inoculation. Special attention was devoted to improving ductility, whilst preserving high damping properties at the same time. The composition and structural modification of medium- and high-aluminium zinc alloys influence their strength, tribological properties and structural stability. In a series of studies, Zn - (10-12) wt. % Al and Zn - (25-26) wt.% Al - (1-2.5) wt.% Cu alloys have been doped with different levels of added Ti. The melted alloys were inoculated with ZnTi-based refiners and it was observed that the dendritic structure is significantly finer already after addition of 50 - 100 ppm Ti to the melted alloys. The alloy's structure and mechanical properties have been studied using: SEM (scanning electron microscopy), LM (light microscopy), dilatometry, pin-on-disc wear, and tensile strength measurements. Grain refinement leads to significant improvement of ductility in the binary high-aluminium Zn-(25-27) Al alloys while in the medium-aluminium alloys the effect is rather weak. In the ternary alloys Zn-26Al-Cu, replacing a part of Cu with Ti allows dimensional changes to be reduced while preserving good tribological properties. Furthermore, the high initial damping properties were nearly entirely preserved after inoculation. The results obtained allow us to characterize grain refinement of the examined high-aluminium zinc alloys as a promising process leading to the improvement of their properties. At the same time, using low melting ZnTi-based master alloys makes it possible to avoid the excessive melt overheating

  15. Recovery of aluminium, nickel-copper alloys and salts from spent fluorescent lamps.

    PubMed

    Rabah, Mahmoud A

    2004-01-01

    This study explores a combined pyro-hydrometallurgical method to recover pure aluminium, nickel-copper alloy(s), and some valuable salts from spent fluorescent lamps (SFLs). It also examines the safe recycling of clean glass tubes for the fluorescent lamp industry. Spent lamps were decapped under water containing 35% acetone to achieve safe capture of mercury vapour. Cleaned glass tubes, if broken, were cut using a rotating diamond disc to a standard shorter length. Aluminium and copper-nickel alloys in the separated metallic parts were recovered using suitable flux to decrease metal losses going to slag. Operation variables affecting the quality of the products and the extent of recovery with the suggested method were investigated. Results revealed that total loss in the glass tube recycling operation was 2% of the SFLs. Pure aluminium meeting standard specification DIN 1712 was recovered by melting at 800 degrees C under sodium chloride/carbon flux for 20 min. Standard nickel-copper alloys with less than 0.1% tin were prepared by melting at 1250 degrees C using a sodium borate/carbon flux. De-tinning of the molten nickel-copper alloy was carried out using oxygen gas. Tin in the slag as oxide was recovered by reduction using carbon or hydrogen gas at 650-700 degrees C. Different valuable chloride salts were also obtained in good quality. Further research is recommended on the thermodynamics of nickel-copper recovery, yttrium and europium recovery, and process economics.

  16. Recovery of aluminium, nickel-copper alloys and salts from spent fluorescent lamps

    SciTech Connect

    Rabah, Mahmoud A

    2004-07-01

    This study explores a combined pyro-hydrometallurgical method to recover pure aluminium, nickel-copper alloy(s), and some valuable salts from spent fluorescent lamps (SFLs). It also examines the safe recycling of clean glass tubes for the fluorescent lamp industry. Spent lamps were decapped under water containing 35% acetone to achieve safe capture of mercury vapour. Cleaned glass tubes, if broken, were cut using a rotating diamond disc to a standard shorter length. Aluminium and copper-nickel alloys in the separated metallic parts were recovered using suitable flux to decrease metal losses going to slag. Operation variables affecting the quality of the products and the extent of recovery with the suggested method were investigated. Results revealed that total loss in the glass tube recycling operation was 2% of the SFLs. Pure aluminium meeting standard specification DIN 1712 was recovered by melting at 800 deg. C under sodium chloride/carbon flux for 20 min. Standard nickel-copper alloys with less than 0.1% tin were prepared by melting at 1250 deg. C using a sodium borate/carbon flux. De-tinning of the molten nickel-copper alloy was carried out using oxygen gas. Tin in the slag as oxide was recovered by reduction using carbon or hydrogen gas at 650-700 deg. C. Different valuable chloride salts were also obtained in good quality. Further research is recommended on the thermodynamics of nickel-copper recovery, yttrium and europium recovery, and process economics.

  17. Identification of monoclinic θ-phase dispersoids in a 6061 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Buchanan, Karl; Ribis, Joël; Garnier, Jérôme; Colas, Kimberly

    2016-04-01

    Intermetallic dispersoids play an important role in controlling the 6xxx alloy series' grain distribution and increasing the alloy's toughness. The dispersoid distribution in a 6061 aluminium alloy (Al-Mg-Si) was analysed by transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The dispersoids had three unique crystal structures: simple cubic ?, body-centred cubic ? and monoclinic (C2/m). While the SC and BCC dispersoids have been well characterized in the literature, a detailed analysis of monoclinic dispersoids has not been presented. Therefore, the current work discusses the chemical composition, crystal structure and morphology of the monoclinic dispersoids.

  18. Electrodeposition of iron and iron-aluminium alloys in an ionic liquid and their magnetic properties.

    PubMed

    Giridhar, P; Weidenfeller, B; El Abedin, S Zein; Endres, F

    2014-05-28

    In this work we show that nanocrystalline iron and iron-aluminium alloys can be electrodeposited from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py1,4]TfO, at 100 °C. The study comprises CV, SEM, XRD, and magnetic measurements. Two different sources of iron(ii) species, Fe(TfO)2 and FeCl2, were used for the electrodeposition of iron in [Py1,4]TfO. Cyclic voltammetry was employed to evaluate the electrochemical behavior of FeCl2, Fe(TfO)2, and (FeCl2 + AlCl3) in the employed ionic liquid. Thick iron deposits were obtained from FeCl2/[Py1,4]TfO at 100 °C. Electrodeposition of iron-aluminium alloys was successful in the same ionic liquid at 100 °C. The morphology and crystallinity of the obtained deposits were investigated using SEM and XRD, respectively. XRD measurements reveal the formation of iron-aluminium alloys. First magnetic measurements of some deposits gave relatively high coercive forces and power losses in comparison to commercial iron-silicon samples due to the small grain size in the nanometer regime. The present study shows the feasibility of preparing magnetic alloys from ionic liquids.

  19. The Potential of the Cold Spray Process for the Repair and Manufacture of Aluminium Alloy Parts

    NASA Astrophysics Data System (ADS)

    Harvey, David; Marrocco, Tiziana

    Being capable of producing deposits up to several centimetres thick, the cold spray process is emerging as an attractive technology for the manufacture and repair of high value aluminium and magnesium components. During the cold spray process fine aluminium or aluminium alloy powders are propelled at high velocities in the solid state at the target substrate. Due to the high velocity particle impacts, strong bonds are formed between the coating and the substrate and between particles within the deposited layer. Metallographic sections of cold sprayed coatings reveal microstructures characterised by very low porosity. With the objective of improving the abrasive wear and erosion resistance of cold sprayed coatings, ceramic reinforcements such as SiC, B4C and Al2O3 have been introduced in the feedstock to produce composite coatings, and these composite materials have been deposited with thicknesses in excess of 25mm. Several applications employing commercially available equipment have achieved industrialisation.

  20. Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part I Microstructural investigation

    NASA Astrophysics Data System (ADS)

    Din, Rameez Ud; Piotrowska, Kamila; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-11-01

    The surface treatment of aluminium alloys under steam containing KMnO4 and HNO3 resulted in the formation of an oxide layer having a thickness of up to 825 nm. The use of KMnO4 and HNO3 in the steam resulted in incorporation of the respective chemical species into the oxide layer. Steam treatment with solution containing HNO3 caused dissolution of Cu and Si from the intermetallic particles in the aluminium substrate. The growth rate of oxide layer was observed to be a function of MnO4- and NO3- ions present in the aqueous solution. The NO3- ions exhibit higher affinity towards the intermetallic particles resulting in poor coverage by the steam generated oxide layer compared to the coating formed using MnO4- ions. Further, increase in the concentration of NO3- ions in the solution retards precipitation of the steam generated aluminium hydroxide layer.

  1. Revealing obliterated engraved marks on high strength aluminium alloy (AA7010) surfaces by etching technique.

    PubMed

    Bong, Yeu Uei; Kuppuswamy, R

    2010-02-25

    Restoration of obliterated engraved marks on high strength Al-Zn-Mg-Cu alloy (AA7010) surfaces by etching technique was studied. The alloy surfaces were mechanically engraved with some identification marks using "Gravograph". The marks were then erased by removing the metal to different levels up to and below the depth of engraving. Five metallographic reagents were tested on the obliterated surfaces by etching. The following two methods (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH were found to be quite effective to reveal the obliterated marks. These two procedures were also able to show effectively the marks obliterated by over-engraving and centre punching. Of the two techniques immersion in phosphoric acid provided more contrast. Interestingly, alternate swabbing of 60% HCl and 40% NaOH presented itself to be the common reagent for restoration on pure aluminium as well as its alloy surfaces. This is evident from our own current experiments and those of earlier researchers [G. Peeler, S. Gutowski, H. Wrobel, G. Dower, The restoration of impressed characters on aluminium alloy motor cycle frames, J. Forensic Ident. 58 (1) (2008) 27-32; M. Izhar M. Baharum, R. Kuppuswamy, A.A. Rahman, Restoration of engraved marks on aluminium surfaces by etching technique, Forensic Sci. Int. 177 (2008) 221-227]. The findings have assumed importance as engines and chassis of cars and frames of firearms are currently made of high strength aluminium alloys and recovery on these surfaces by current methods is not satisfactory.

  2. Performance of AA5052 alloy anode in alkaline ethylene glycol electrolyte with dicarboxylic acids additives for aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Wang, DaPeng; Zhang, DaQuan; Lee, KangYong; Gao, LiXin

    2015-11-01

    Dicarboxylic acid compounds, i.e. succinic acid (SUA), adipic acid (ADA) and sebacic acid (SEA), are used as electrolyte additives in the alkaline ethylene glycol solution for AA5052 aluminium-air batteries. It shows that the addition of dicarboxylic acids lowers the hydrogen gas evolution rate of commercial AA5052 aluminium alloy anode. AA5052 aluminium alloy has wide potential window for electrochemical activity and better discharge performance in alkaline ethylene glycol solution containing dicarboxylic acid additives. ADA has the best inhibition effect for the self-corrosion of AA5052 anode among the three dicarboxylic acid additives. Fourier transform infrared spectroscopy (FT-IR) reveals that dicarboxylic acids and aluminium ions can form coordination complexes. Quantum chemical calculations shows that ADA has a smaller energy gap (ΔE, the energy difference between the lowest unoccupied orbital and the highest occupied orbital), indicating that ADA has the strongest interaction with aluminium ions.

  3. Study of solid-solution hardening in binary aluminium-based alloys

    NASA Astrophysics Data System (ADS)

    Draissia, Mohamed; Debili, Mohamed-Yacine

    2005-09-01

    Solid-solution formation in binary aluminium-based alloys is due essentially to the combined effects of the size and valence of solvent and solute atoms, as expected by the four Hume-Rothery rules. The lattice parameter of aluminium in the solid solution of the sputtered Al-Fe films is [Al-a (Å)=4.052-6.6×10-3Y]. The increasing and decreasing evolution of the lattice parameter of copper [Cu-a (Å)=3.612+1.8×10-3Z] and aluminium [Al-a (Å)=4.048-1.6×10-3X] in the sputtered Al-1.8 to 92.5 at. % Cu films is a result of the difference in size between the aluminium and copper atoms. The low solubility of copper in aluminium (<1.8 at % Cu) is due to the valences of solvent and solute atoms in contrast with other sputtered films prepared under similar conditions, such as Al-Mg (20 at. % Mg), Al-Ti (27 at. % Ti), Al-Cr (5at. % Cr) and Al-Fe (5.5 at. % Fe) where the solubility is due to the difference in size.

  4. Aluminium alloys with transition metals prepared by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Kucera, V.; Prusa, F.; Vojtech, D.

    2017-02-01

    Powder metallurgy represented by mechanical alloying and spark plasma sintering was used for preparation of the AlFe16 and the AlSi20Fe16 alloys. Microstructure of the both alloys consisted of very fine intermetallic phases homogenously dispersed in the matrix of α-Al solid solution. Fine nature of microstructure led to promising results of compressive stress-strain tests performed at laboratory and elevated temperature of 400 °C. The compressive strengths of the AlSi20Fe16 and the AlFe16 alloys at laboratory temperature were 780 MPa and 508 MPa, respectively. Elevated temperature resulted in drop of the compressive strengths to 480 MPa and 211 MPa, respectively. However, the results of investigated alloys outperformed the thermally stable AlSi12Cu1Mg1Ni1 (wt. %) used as reference material.

  5. HRTEM and HAADF-STEM of precipitates at peak ageing of cast A319 aluminium alloy.

    PubMed

    Wiengmoon, Amporn; Pearce, John T H; Chairuangsri, Torranin; Isoda, Seiji; Saito, Hikaru; Kurata, Hiroki

    2013-02-01

    High-resolution transmission electron microscopy (HRTEM) and high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM) were applied to investigate the precipitates formed during age hardening at 170±5°C for up to 48h of cast A319 aluminium alloy (Al-4.93wt%Si-3.47wt%Cu). The precipitates at the peak-aged condition have been identified as mainly θ" together with a smaller amount of θ'. It is proposed that the θ" is responsible for hardening at peak ageing at 170°C of the cast A319 aluminium alloy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Two-Scale Modelling of Effects of Microstructure and Thermomechanical Properties on Dynamic Performance of an Aluminium Alloy

    DTIC Science & Technology

    2010-09-01

    monolithic metallic plate fabricated from a precipitate-strengthened aluminium alloy . The alloy of study is Al 2139, consisting primarily of elemental Al...polycrystalline Al-Cu-Mg alloy . A limited number of experiments have been conducted to assess ductility, fracture strength and high -rate behaviour of...effects of crystallographic texture on the high -rate shear response of a Ti-6Al-4V alloy . Schoenfeld and Kad (2002) found that lattice orientations affect

  7. Measurement research for pitting potential of aluminium alloy with chromate passivation layers

    NASA Astrophysics Data System (ADS)

    Su, Z. H.; Dai, Y.; Ma, Q. Y.; Wang, J. N.; Zheng, C. Q.

    2017-01-01

    This paper describes common technology for measuring corrosion resistant properties of aluminium alloy with chromate passivation layers. It gives a resolution to characterize corrosion resistant properties of pitting potential. The method, including sample preparation, measuring polarization and the determining of pitting corrosion potential, was proposed. Tests of repeatability and reproducibility can meet the demand of measurement precision. In addition, comparison of the positional relationships between polarization curves and nominal pitting corrosion potential was provided to judge products.

  8. TEM and HRTEM studies of ball milled 6061 aluminium alloy powder with Zr addition.

    PubMed

    Lityńska-Dobrzyńska, L; Dutkiewicz, J; Maziarz, W; Rogal, Ł

    2010-03-01

    The effect of mechanical alloying on the microstructure of atomized 6061 aluminium alloy powder and 6061 powder with a zirconium addition was studied in the work. The atomized 6061 aluminium alloy powder and 6061 powder with addition of 2 wt.% Zr were milled in a planetary ball mill and investigated using X-ray diffraction measurements, conventional and high-resolution electron microscopy (TEM/HRTEM) and high-angle annular dark field scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis. An increase of stresses was observed in milled powders after the refinement of crystallites beyond 100 nm. In the powder with zirconium addition, some part of the Zr atoms diffused in aluminium forming a solid solution containing up to 0.5 wt.% Zr. The remaining was found to form Zr-rich particles containing up to 88 wt.% Zr and were identified as face centred cubic (fcc) phase with lattice constant a= 0.48 nm. That fcc phase partially transformed into the L1(2) ordered phase. Eighty-hour milling brought an increase of microhardness (measured with Vickers method) from about 50 HV (168 MPa) for the initial 6061 powder to about 170 HV (552 MPa). The addition of zirconium had no influence on the microhardness.

  9. Experimental investigations on thermo mechanical behaviour of aluminium alloys subjected to tensile loading and laser irradiation

    NASA Astrophysics Data System (ADS)

    Jelani, Mohsan; Li, Zewen; Shen, Zhonghua; Sardar, Maryam; Tabassum, Aasma

    2017-05-01

    The present work reports the investigation of the thermal and mechanical behaviour of aluminium alloys under the combined action of tensile loading and laser irradiations. The two types of aluminium alloys (Al-1060 and Al-6061) are used for the experiments. The continuous wave Ytterbium fibre laser (wavelength 1080 nm) was employed as irradiation source, while tensile loading was provided by tensile testing machine. The effects of various pre-loading and laser power densities on the failure time, temperature distribution and on deformation behaviour of aluminium alloys are analysed. The experimental results represents the significant reduction in failure time and temperature for higher laser powers and for high load values, which implies that preloading may contribute a significant role in the failure of the material at elevated temperature. The reason and characterization of material failure by tensile and laser loading are explored in detail. A comparative behaviour of under tested materials is also investigated. This work suggests that, studies considering only combined loading are not enough to fully understand the mechanical behaviour of under tested materials. For complete characterization, one must consider the effect of heating as well as loading rate.

  10. Protection of 2024-T3 aluminium alloy by corrosion resistant phytic acid conversion coating

    NASA Astrophysics Data System (ADS)

    Shi, Hongwei; Han, En-Hou; Liu, Fuchun; Kallip, Silvar

    2013-09-01

    The corrosion protection properties of environmentally friendly phytic acid conversion coatings were studied on 2024-T3 aluminium alloy. The films were prepared under acidic conditions with various pH values and characterised by SEM, EDS, ATR-FTIR and electrochemical techniques. The results indicate that the conversion coatings obtained by immersing the alloy in phytic acid solutions at pH from 3 to 5.5 provide excellent corrosion resistance. ATR-FTIR confirms that the film is formed by deposition of reaction products between Al3+ and phosphate groups in phytic acid molecules. The conformation models of the deposition film are proposed.

  11. Pulsed Nd-YAG laser welding of A SiC particulate reinforced aluminium alloy composite

    NASA Astrophysics Data System (ADS)

    Yue, T. M.; Xu, J. H.; Man, H. C.

    1997-01-01

    This paper examines the laser welding behaviour of a SiC particulate reinforced Al-alloy 2124 composite using a pulsed Nd-YAG laser. The influences of laser welding parameters of laser intensity, pulse duration and the beam's focus position on the depth of weld penetration as well as the size of fusion zone were investigated. These investigations have led to an optimum welding condition proposed for pulsed laser welding of SiC particulate reinforced aluminium alloy composites with minimum defects.

  12. Effect of metal coatings on mechanical properties of aluminium alloy

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, V.; Dileep, B. P.; Mohan Kumar, S.; Phanibhushana, M. V.

    2017-07-01

    This investigation mainly targeted on study of hardness and tensile properties of Al 7075 with different metal coatings like Nickel, Zinc and cadmium. Coating of these metals on Al 7075 is successfully achieved by time dependent electroplating method for different thicknesses of 10, 15 and 20 Microns. These metal coated Al-7075 specimens were tested for hardness and tensile properties according to the ASTM standards. It's found that Nickel coated alloy shows excellent hardness and tensile properties compared to Zinc and Cadmium coated alloys. 20 µm Nickel coated alloy exhibits highest hardness number of 102 HRB and Maximum Tensile Strength of 603 MPa than Zinc and Cadmium coated alloy. The microstructural studies authenticated that the coating of Nickel, zinc and cadmium on Al 7075 is homogeneous.

  13. High-Rate Compaction of Aluminium Alloy Foams

    SciTech Connect

    Harrigan, J. J.; Hung, Y.-C.; Tan, P. J.; Bourne, N. K.; Withers, P. J.; Reid, S. R.; Millett, J. C. F.; Milne, A. M.

    2006-07-28

    The response of aluminium foams to impact can be categorised according to the impact velocity. Tests have been carried out at a range of impact velocities from quasi-static to velocities approaching the speed of sound in the foam. Various experimental arrangements have been employed including pneumatic launcher tests and plate impact experimants at velocities greater than 1000 m s-1. The quasi-static compression behaviour was approximately elastic, perfectly-plastic, locking. For static and dynamic compression at low impact velocities the deformation pattern was through the cumulative multiplication of discrete, non-contiguous crush bands. Selected impact tests are presented here for which the impact velocity is less than the velocity of sound, but above a certain critical impact velocity so that the plastic compression occurs in a shock-like manner and the specimens deform by progressive cell crushing. Laboratory X-ray microtomography has been employed to acquire tomographic datasets of aluminium foams before and after tests. The morphology of the underformed foam was used as the input dataset to an Eulerian code. Hydrocode simulations were then carried out on a real microstructure. These simulations provide insight to mechanisms associated with the localization of deformation.

  14. High-Rate Compaction of Aluminium Alloy Foams

    NASA Astrophysics Data System (ADS)

    Harrigan, J. J.; Hung, Y.-C.; Tan, P. J.; Bourne, N. K.; Withers, P. J.; Reid, S. R.; Millett, J. C. F.; Milne, A. M.

    2006-07-01

    The response of aluminium foams to impact can be categorised according to the impact velocity. Tests have been carried out at a range of impact velocities from quasi-static to velocities approaching the speed of sound in the foam. Various experimental arrangements have been employed including pneumatic launcher tests and plate impact experimants at velocities greater than 1000 m s-1. The quasi-static compression behaviour was approximately elastic, perfectly-plastic, locking. For static and dynamic compression at low impact velocities the deformation pattern was through the cumulative multiplication of discrete, non-contiguous crush bands. Selected impact tests are presented here for which the impact velocity is less than the velocity of sound, but above a certain critical impact velocity so that the plastic compression occurs in a shock-like manner and the specimens deform by progressive cell crushing. Laboratory X-ray microtomography has been employed to acquire tomographic datasets of aluminium foams before and after tests. The morphology of the underformed foam was used as the input dataset to an Eulerian code. Hydrocode simulations were then carried out on a real microstructure. These simulations provide insight to mechanisms associated with the localization of deformation.

  15. High-Rate Compaction of Aluminium Alloy Foams

    NASA Astrophysics Data System (ADS)

    Harrigan, J. J.; Millett, J. C. F.; Milne, A. M.

    2005-07-01

    The response of aluminium foams to impact can be categorised by the impact velocity. Tests are reported ranging from quasi-static to impact velocities greater than the speed of sound in the foam. The techniques used ranging from drop-hammer and pneumatic launcher tests, to plate impact at velocities greater than 1000 m s-1. The quasi-static compression behaviour was elastic, perfectly-plastic, locking. For static and dynamic compression at low impact velocities, post-impact examination of partially crushed specimens showed that deformation was through the cumulative multiplication of crush bands. If the impact velocity is less than the velocity of sound, but above a certain critical impact velocity, the plastic compression occurs in a shock-like manner and the specimens deform by progressive cell crushing. At higher impact velocities the compaction front is not preceded by an elastic wave. Laboratory X-ray microtomography has been employed to acquire tomographic datasets of aluminium foams before and after tests. The morphology of the underformed foam was input as the input dataset to an Eulerian code. Hydrocode simulations were then carried out on real microstructure. These simulations provide insight to mechanisms associated with the localization of deformation.

  16. The transition from discontinuous to continuous recrystallization in some aluminium alloys I - the deformed state

    SciTech Connect

    Jazaeri, H.; Humphreys, F.J

    2004-06-21

    The microstructures developed during deformation to large rolling strains in single and two-phase aluminium alloys with a wide range of grain sizes has been investigated, and the major parameters of the microstructure determined by high resolution electron backscatter diffraction (EBSD). It is found that the behaviour of initially fine-grained (<5 {mu}m) alloys is significantly different from that of the large-grained (>50 {mu}m) alloys. In the finer-grained alloys no significant grain fragmentation occurs, and at larger strains, when the spacing of high angle boundaries approaches the crystallite size, a considerable amount of the high angle boundary is removed by a process of dynamic recovery.

  17. Numerical simulation of early stages of oxide formation in molten aluminium magnesium alloys in a reverberatory furnace

    NASA Astrophysics Data System (ADS)

    Kanti De, Anindya; Mukhopadhyay, Achintya; Sen, Swarnendu; Puri, Ishwar K.

    2004-05-01

    A significant amount of aluminium is processed by melting aluminium scrap that contains small amounts of magnesium. A major drawback of aluminium production in secondary melt furnaces is the formation of dross or aluminium oxide by the oxidation of the molten metal. Since aluminium scrap forms a major source of the metal in secondary aluminium processing, the presence of alloying elements plays a key role in the oxidation process. Here, we consider the early stage of oxidation of an Al-Mg alloy during which primarily the oxidation of magnesium to its oxide occurs. Our model simulates the process in an aluminium melting furnace and considers metal oxidation to be diffusion limited. The phenomenon is assumed to be one-dimensional and the reaction of Al/Mg with O2 to be infinitely fast. We are able to obtain a closed form analytical solution of the evaporation rate and the amount of oxide that is formed. We find that the evaporation of the metal vapour and its oxidation depend on the furnace size, melt composition, melt temperature, gas temperature and oxygen concentration in the gas. Oxide formation decreases with increasing furnace height and with decreasing oxygen concentration and melt temperature. Dross formation is weakly dependent on the ambient temperature and alloy composition. The results indicate that there are essentially two parameters, namely, the equivalence ratio of the fuel-air mixture (which controls the ambient oxygen concentration) and the melt temperature that can be manipulated to influence oxide formation in practical furnaces.

  18. Precipitation, strength and work hardening of age hardened aluminium alloys

    NASA Astrophysics Data System (ADS)

    Ryen, Ø.; Holmedal, B.; Marthinsen, K.; Furu, T.

    2015-08-01

    The strength and work hardening of age hardened AA6063 and AA6082 alloys have been investigated in terms of a detailed characterization of precipitate and dislocation structures obtained by TEM and SEM. Tensile and compression tests were performed at as quenched, peak aged and severely aged conditions. A strong work hardening in the as quenched condition was found, similar to AlMg alloys with twice as much alloying elements in solid solution. It was found that the initial work hardening rate and the critical failure strain are both smallest at the peak aged condition. During large deformations the needle-shaped precipitates are sheared uniformly by dislocations altering their <001> orientations, which indicates extensive cross slip. In the overaged condition the early initial work hardening is larger than at the peak aged condition, but followed by a weak linear work hardening, apparently directly entering stage IV at a low strain. Cracked, needle-shaped precipitates were seen at larger strains.

  19. On the micromechanisms responsible for bilinearity in fatigue power-law relationships in aluminium-lithium alloys

    SciTech Connect

    Prasad, N.E.; Malakondaiah, G.; Kutumbarao, V.V.

    1997-09-01

    Aluminium-lithium alloys, like many other aerospace structural alloys, exhibit bilinearity in power-law relationships between high strain, low cycle fatigue life (in terms of number of reversals to failure, 2N{sub f}) and plastic strain amplitude ({Delta}{epsilon}{sub p}/2) or average stress amplitude ({Delta}{sigma}/2) or average plastic strain energy per cycle ({Delta}W{sub p}). In the present paper the micromechanisms leading to bilinear fatigue power-law relationships, especially the Coffin-Manson (C-M) relationship, in aluminium-lithium alloys are compiled and discussed.

  20. Cavitation erosion resistance of microarc oxidation coating on aluminium alloy

    NASA Astrophysics Data System (ADS)

    Cheng, Feng; Jiang, Shuyun; Liang, Jun

    2013-09-01

    Two ceramic coatings are prepared on 2124 aluminum alloy by microarc oxidation (MAO) technology. To explore the cavitation erosion resistance of the MAO coating, cavitation tests were performed by using a rotating-disk test rig. The mass losses, surface morphologies, chemical compositions and the phase constituents of the samples after cavitation tests were examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the MAO coatings can extend the incubation period of aluminum alloy, and thus enhance the cavitation erosion resistance as compared to the untreated aluminum alloy samples. After duration of 63 h cavitation test, a lot of erosion pits and the particles in various shapes can be observed on the surfaces of the aluminum alloy samples, while only a few erosion pits are observed on the MAO coatings. Moreover, the mean depths of erosion on the MAO coatings are lower in the first 30 h and are independent on erosion time. The results show that the cavitation erosion of MAO coating is governed by water mechanical impaction, resulting from the effects of brittle fracture of the MAO coating.

  1. A hybrid aluminium alloy and its zoo of interacting nano-precipitates

    SciTech Connect

    Wenner, Sigurd; Marioara, Calin Daniel; Andersen, Sigmund Jarle; Ervik, Martin; Holmestad, Randi

    2015-08-15

    An alloy with aluminium as its base element is heat treated to form a multitude of precipitate phases known from different classes of industrial alloys: Al–Cu(–Mg), Al–Mg–Si–Cu, and Al–Zn–Mg. Nanometer-sized needle-shaped particles define the starting point of the phase nucleation, after which there is a split in the precipitation sequence into six phases of highly diverse compositions and morphologies. There are several unique effects of phases from different alloy systems being present in the same host lattice, of which we concentrate on two: the replacement of Ag by Zn on the Ω interface and the formation of combined plates of the θ′ and C phases. Using atomically resolved scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy, we investigate the formation mechanisms, crystal structures and compositions of the precipitates. - Graphical abstract: Display Omitted - Highlights: • An aluminium alloy composition in-between the 2/6/7xxx systems was investigated. • Six different phases from the three systems coexist in an over-aged state. • All phases with 〈001〉{sub Al} coherencies can nucleate on 6xxx needle precipitates. • Modified theta′ and omega interfaces are observed.

  2. Analysis of wear properties of aluminium based journal bearing alloys with and without lubrication.

    NASA Astrophysics Data System (ADS)

    Mathavan, J. Joy; Patnaik, Amar

    2016-09-01

    Apart from classical bearing materials, Aluminium alloys are used as bearing materials these days because of their superior quality. In this analysis, new Aluminium based bearing materials, with filler metals Si, Ni, and Cr are prepared by metal mould casting in burnout furnace machine, and tribological properties of these alloys with and without lubrication were tested. The experiments for wear with lubrication are conducted on multiple specimen tester and experiments without lubrication is conducted on Pin on disk tribometer. The disc material used was SAE 1050 steel. Wear tests were conducted at a sliding speed of 0.785 m/s and at a normal load of 20 N. Coefficient of friction values, temperature changes and wear of the specimens were plotted on graph according to the above mentioned working conditions. Hardness and weight losses of the specimens were calculated. The obtained results demonstrate how the friction and wear properties of these samples have changed with the % addition of Silicon, Chromium and Nickel to the base metal aluminium.

  3. Study on optimal surface property of WC-Co cutting tool for aluminium alloy cutting

    NASA Astrophysics Data System (ADS)

    Nizar, Mohd; Arimatsu, Naoya; Kawamitsu, Hiroshi; Takai, Kazuteru; Fukumoto, Masahiro

    2016-02-01

    The light weight property as well as high corrosion resistance of aluminium alloy has increased their demand especially in automobile industries. Aluminium alloy as a matter of fact has a low melting point and high ductility that severely adhere to the cutting tool surface and cause deterioration of chip evacuation. This problem often resulting in tools breakage. In this paper, in order to impart functions of anti-adhesion, we propose a technique by controlling the grinding marks micro texture on the tool surface by using the blast polishing treatment without any coating technologies. The results show that the tool which underwent polishing treatment reduces the cutting force as well as the aluminium adherence during the initial cutting process, and become worst as the process cutting continues. These results indicate that grinding mark texture improves the anti-adhesion by reducing the contact area during cutting and provide storage for the lubricant. In addition, too much polishing on the tool surface may remove these textures and resultantly worsen the tool performance.

  4. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion corrosion processes

    NASA Astrophysics Data System (ADS)

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Martínez-Nicolás, Ginés

    2007-06-01

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of α-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  5. Surface formation in direct chill (DC) casting of 6082 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Bayat, N.; Carlberg, T.

    2016-03-01

    Surface defects in aluminium billet production are a real problem for the subsequent extrusion procedure. Extrusion productivity can be influenced by the surface properties, which is defined as surface appearance, surface segregation zone depth and large Mg2Si and β-particles (Al5FeSi). In this research the surface formation during DC casting of 6082 aluminium billets produced by the air slip technology is studied. The surface microstructures of 6082 aluminium alloys with smooth and wavy surface appearances were investigated, including segregation zone depths and phase formation. The results were discussed based on the exudation of liquid metal through the mushy zone. The specific appearance of the wavy surface of 6082 alloys was correlated to how the oxide skin adheres to the underlying mushy zone and coupled to the dendritic coherency and surface tension of the skin. The occurrence of different phases at the very surface and in the layer just below was explained by variations in solidification directions and subsequent segregation patterns.

  6. The fatigue response of the aluminium-lithium alloy, 8090

    NASA Technical Reports Server (NTRS)

    Birt, M. J.; Beevers, C. J.

    1989-01-01

    The fatigue response of an Al-Li-Cu-Mg-Zr (8090) alloy has been studied at room temperature. The initiation and growth of small and long cracks has been examined at R = 0.1 and at a frequency of 100 Hz. Initiation was observed to occur dominantly at sub-grain boundaries. The growth of the small cracks was crystallographic in character and exhibited little evidence of retardation or arrest at the grain boundaries. The long crack data showed the alloy to have a high resistance to fatigue crack growth with underaging providing the optimum heat treatment for fatigue crack growth resistance. In general, this can be attributed to high levels of crack closure which resulted from the presence of extensive microstructurally related asperities.

  7. The fatigue response of the aluminium-lithium alloy, 8090

    NASA Technical Reports Server (NTRS)

    Birt, M. J.; Beevers, C. J.

    1989-01-01

    The fatigue response of an Al-Li-Cu-Mg-Zr (8090) alloy has been studied at room temperature. The initiation and growth of small and long cracks has been examined at R = 0.1 and at a frequency of 100 Hz. Initiation was observed to occur dominantly at sub-grain boundaries. The growth of the small cracks was crystallographic in character and exhibited little evidence of retardation or arrest at the grain boundaries. The long crack data showed the alloy to have a high resistance to fatigue crack growth with underaging providing the optimum heat treatment for fatigue crack growth resistance. In general, this can be attributed to high levels of crack closure which resulted from the presence of extensive microstructurally related asperities.

  8. 3D study of intermetallics and their effect on the corrosion morphology of rheocast aluminium alloy

    SciTech Connect

    Mingo, B.; Arrabal, R.; Pardo, A.; Matykina, E.; Skeldon, P.

    2016-02-15

    In the present study, the effect of heat treatment T6.1 on the microstructure and corrosion behaviour of rheocast aluminium alloy A356 is investigated on the basis of 2D/3D characterization techniques and electrochemical and SKPFM measurements. Heat treatment strengthens the α-Al matrix, modifies the intermetallic particles and spheroidizes eutectic Si. These changes do not modify significantly the corrosion behaviour of the alloy. 3D SEM-Tomography clearly shows that the corrosion advances in the shape of narrow paths between closely spaced intermetallics without a major influence of eutectic Si. - Highlights: • T6.1 spheroidizes Si, strengthens the matrix and modifies the intermetallics. • Electrochemical behaviour of untreated and heat-treated alloys is similar. • 3D SEM-Tomography provides additional information on the corrosion morphology. • Corrosion advances as paths between intermetallics with little influence of Si.

  9. Fabrication of self-healing super-hydrophobic surfaces on aluminium alloy substrates

    SciTech Connect

    Wang, Yang; Wei Liu, Xiao; Zhang, Hai Feng Zhou, Zhi Ping

    2015-04-15

    We present a method to fabricate a super-hydrophobic surface with a self-healing ability on an aluminium alloy substrate. The coatings are obtained by combining a two-step process (first, the substrate is immersed in a solution of HCl, HF and H{sub 2}O, and then in boiling water) and succeeding surface fluorination with a solution of poly(vinylidene-fluoride-co-hexafluoropropylene) and a fluoroalkyl silane. The morphological features and chemical composition were studied by scanning electron micrometry and energy-dispersive X-ray spectroscopy. The prepared super-hydrophobic aluminium surfaces showed hierarchical structures forming pores, petals and particles with a contact angle of 161° and a sliding angle of 3°.

  10. Finite Element Analysis of Warpage in Laminated Aluminium Alloy Plates for Machining of Primary Aeronautic Parts

    SciTech Connect

    Reis, A. C.; Moreira Filho, L. A.; Menezes, M. A.

    2007-04-07

    The aim of this paper consists in presenting a method of simulating the warpage in 7xxx series aluminium alloy plates. To perform this simulation finite element software MSC.Patran and MSC.Marc were used. Another result of this analysis will be the influence on material residual stresses induced on the raw material during the rolling process upon the warpage of primary aeronautic parts, fabricated through machining (milling) at Embraer. The method used to determinate the aluminium plate residual stress was Layer Removal Test. The numerical algorithm Modified Flavenot Method was used to convert layer removal and beam deflection in stress level. With such information about the level and profile of residual stresses become possible, during the step that anticipate the manufacturing to incorporate these values in the finite-element approach for modelling warpage parts. Based on that warpage parameter surely the products are manufactured with low relative vulnerability propitiating competitiveness and price.

  11. Properties of experimental copper-aluminium-nickel alloys for dental post-and-core applications

    PubMed Central

    Rittapai, Apiwat; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

    2014-01-01

    PURPOSE This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. MATERIALS AND METHODS Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (α=0.05). The alloy toxicity was evaluated according to the ISO standard. RESULTS The solidus and liquidus points of experimental alloys ranged from 1023℃ to 1113℃ and increased as the nickel content increased. The highest ultimate tensile strength (595.9 ± 14.2 MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity (113.9 ± 8.0 and 122.8 ± 11.3 GPa, respectively), but also had a value of 0.2% proof strength (190.8 ± 4.8 and 198.2 ± 3.4 MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. CONCLUSION The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications. PMID:25006386

  12. Electron irradiation of aluminium-zinc alloys. 3. Radiation-enhanced precipitation in an aluminium-4.5 at% zinc alloy

    NASA Astrophysics Data System (ADS)

    Zhang, Y. G.

    1989-06-01

    An aluminium-4.5 at% zinc alloy was irradiated at temperatures between 25 and 170°C to doses of 7 dpa to 14 dpa at a dose rate of ~3.88 × 10 -3dpa/s. Irradiation produced a very high density of coherent G.P. zones in the temperature range ~80-~130°C, coherent plate shaped precipitates in the temperature range ~130-~160°C and, under some irradiation conditions, large Zn precipitates on the foil surfaces. No precipitates occurred along the grain boundaries in the irradiated area. The matrix precipitation was interpreted in terms of the theory of Cauvin and Martin. The surface precipitation is ascribed to surface segregation of Zn and the non-appearance of precipitates along the grain boundaries in the irradiated area is thought to be due to the high metastability of the precipitates on the boundaries under irradiation.

  13. The flash-butt welding of aluminium alloys

    NASA Astrophysics Data System (ADS)

    Kuchuk-Iatsenko, S. I.; Cherednichok, V. T.; Semenov, L. A.

    Flash-butt welding (FBW) of high-strength aerospace Al alloys is conducted without gaseous-medium shielding and has undergone substantial development in the direction of automated operations. FBW yields virtually no pores, discontinuities, or cracks, and is therefore ideal for gas-impermeable joints. The dimensional accuracies achievable by FBW are a function of weld are inner stresses that are a full order of magnitude smaller than those of arc-welding methods. NDI methods can be incorporated into an automated FBW apparatus for direct inspection of welds.

  14. Further studies of the anodic dissolution in sodium chloride electrolyte of aluminium alloys containing tin and gallium

    NASA Astrophysics Data System (ADS)

    Nestoridi, Maria; Pletcher, Derek; Wharton, Julian A.; Wood, Robert J. K.

    As part of a programme to develop a high power density, Al/air battery with a NaCl brine electrolyte, the high rate dissolution of an aluminium alloy containing tin and gallium was investigated in a small volume cell. The objective was to define the factors that limit aluminium dissolution in condition that mimic a high power density battery. In a cell with a large ratio of aluminium alloy to electrolyte, over a range of current densities the extent of dissolution was limited to ∼1000 C cm -2 of anode surface by a thick layer of loosely bound, crystalline deposit on the Al alloy anode formed by precipitation from solution. This leads to a large increase in impedance and acts as a barrier to transport of ions.

  15. Strength of the aluminium alloy 6082-T6 under high strain-rate conditions

    SciTech Connect

    Harrigan, J. J.; Millett, J. C. F.; Bourne, N. K.

    2007-12-12

    The measurement of shear strength via the use of lateral stress gauges has been shown to be a viable technique in a number of materials. An experimental investigation on the intermediate-rate behaviour and shock response of the aluminium alloy, 6082-T6, is reported here. Results obtained using the lateral stress gauge technique show that the shear strength increases with impact stress. The lateral stress behind the shock front is seen to be relatively flat, unlike many other face-centred cubic metals and alloys, where a decrease in lateral stress indicates an increase in shear strength. This unusal response may be a reflection of the high stacking fault energy of aluminium and its alloys resulting in a reduction of the work hardening (i.e. increases in dislocation and/or twin density). Further plate impact results show that the Hugoniot of 6082-T6 is in effect identical to that of the more widely known 6061-T6. Split Hopkinson pressure bar results are used to provide a fuller picture of the rate-dependant behaviour of 6082-T6 over a range of loading rates and conditions.

  16. Effect of the nature of grain boundary regions on cavitation of a superplastically deformed aluminium alloy

    SciTech Connect

    Blandin, J.J.; Varloteaux, A.; Suery, M.; Hong, B.; L`Esperance, G.

    1996-06-01

    Superplastic deformation of aluminium alloys induces cavity formation throughout the material, so that superplastic forming usually requires to be carried out under superimposed gas pressure to minimize strain-induced damage. This paper deals with the beneficial effects of heat treatment at high temperature for several hours before deformation on cavitation behavior of a superplastically deformed 7475 alloy. Transmission electron microscopy observations show that several microstructural transformations are induced by superplastic deformation and affected by the heat treatment. At first, the generation of dispersoid free zones at the periphery of the grains is observed, the composition of which depends on the prior history of the specimen. Secondly, the formation of long thin fibers extending in the cavities in the as received specimens, these fibers being no longer present in the heat-treated conditions. A TEM characterization of the fibers is presented and a mechanism of their formation is discussed. Such a reduction of the cavitation level for a given strain is interesting in view of superplastic forming of aluminium alloys under atmospheric pressure.

  17. Microstructure refinement of commercial 7xxx aluminium alloys solidified by the electromagnetic vibration technique

    NASA Astrophysics Data System (ADS)

    Li, M.; Tamura, T.; Omura, N.; Murakami, Y.; Tada, S.

    2016-03-01

    This paper examines the microstructure refinement of commercial 7xxx aluminium alloys solidified by the electromagnetic vibration technique (EMV) as a function of vibration frequency, f. The microstructure evolution reveals that at the low frequency of f = 62.5 Hz, the solidified microstructure is coarse and with the increase of vibration frequency to f = 500 Hz, the grain size becomes the finest and further increase of frequency to f = 2000 Hz results in coarsening of microstructures. The refinement mechanism is clarified when considering the significant difference in electrical resistivities of the solid and the liquid in mushy zone, in which both phases coexist and subject to vibration. The frequency-dependent refinement behaviour is revealed when the displacement of the mobile solid and sluggish liquid is taken into account during solidification. In contrast to 3xxx aluminium alloys, no giant compounds have been discerned in the present 7xxx alloy regardless of the solidification condition. The formation of crystalline twin is briefly discussed when considering the vibration condition.

  18. Rapid and selective chelatometric titration of aluminium in non-ferrous alloys.

    PubMed

    Nan, Z; Yuan-Xiang, G; Zhi-Ren, L; Eei-Yong, C

    1985-12-01

    A rapid chelatometric method for the determination of Al (4-20%) in magnesium, copper and chromium-aluminium-iron alloys is proposed. HEDTA is used as titrant and Zn solution as back-titrant, with hydrazidazol as indicator. Mn(II), Cu(II), Cd, Zn, Pb, Co(II), Ni, Hg(II), Fe(III), Bi, Cr(III), Sb(III), Ce(III), La, Sn(IV), Ti(IV), Zr and Mo(VI) do not interfere. High selectivity is achieved by a combination of group separation, masking and interference correction. The coefficient of variation varies from 0.2 to 1%.

  19. Grain boundary segregation and hydrogen-induced fracture in 7050 aluminium alloy

    SciTech Connect

    Song, R.G.; Tseng, M.K.; Zhang, B.J.; Liu, J.; Jin, Z.H.; Shin, K.S.

    1996-08-01

    The relationships between grain boundary segregation and crack growth of stress corrosion and corrosion fatigue in 7050 aluminium alloy have been investigated under various aging conditions; the effects of grain boundary segregation on intergranular fracture work have been calculated using a quasichemical approach. The results show that the hydrogen content at the crack tip and the crack growth rate increase with the concentration of solid solution Mg on increasing grain boundary; both Mg and H segregation induce the intergranular fracture work to decrease. Mg segregation accelerates H enriching and crack propagation. It is indicated that a Mg-H interaction occurs in the processes of corrosion fatigue as well as stress corrosion.

  20. Experimental evaluation of machining parameters in machining of 7075 aluminium alloy with cryogenic liquid nitrogen coolant

    NASA Astrophysics Data System (ADS)

    Muthuraman, V.; Arunkumar, S.

    2017-03-01

    The experimental results on investigation on the turning of 7075 aluminium alloy, using Cryogenic Liquid Nitrogen (LN2) as a coolant was analyzed in this paper. The influence of the cryogenic LN2 coolant compared with that of the conventional coolant on the cuting performance parameters, such as the cutting force, cutting temperature, andbsurface finish was analysed and investigated. The use of the cryogenic liquid nitrogen coolant influenced the cutting temperature and the cutting force by about 17 to 29% and 11 to 20% reduction respectively. The surface finish value of the machined workpiece is about 15 to 23% better than that of the conventional coolant.

  1. A comparative assessment of crystallite size and lattice strain in differently cast A356 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Roy, H.; Lohar, A. K.; Samanta, S. K.; Tiwari, S.; Dutta, K.

    2015-02-01

    In this investigation, A356 aluminium alloy has been prepared by different routes viz. gravity casting, rheo pressure die casting (RPDC) and RPDC with T6 heat treatment. X-ray diffraction studies of these samples have been done in the scanning range of 20 - 90°. X-ray peak broadening analysis has been used to estimate the crystallite size and lattice stain, in all the samples. The sample prepared by RPDC with T6 treatment has comparatively smaller crystallite size and lesser lattice strain than gravity cast and RPDC samples.

  2. Microstructure evolution in age-hardenable aluminium alloy during processing by hydrostatic extrusion.

    PubMed

    Lewandowska, M

    2006-10-01

    In the present work, scanning and transmission electron microscopy were used to investigate the microstructural evolution occurring during the hydrostatic extrusion of an age-hardenable aluminium alloy. It was shown that processing by hydrostatic extrusion leads to grain refinement to 95 nm in equivalent diameter. Hydrostatic extrusion also influences the geometrical parameters of two different types of particle: intermetallic inclusions and precipitates. The intermetallic inclusions slightly decrease in mean equivalent diameter, but their size remains at the micrometre level. The precipitates are fragmented to nanoscale spherical particles, and their evolution delays the process of grain refinement.

  3. Preparation of aluminium-magnesium alloys and some valuable salts from used beverage cans.

    PubMed

    Rabah, Mahmoud A

    2003-01-01

    The purpose of this work is to recover standard aluminium-magnesium alloy(s) and some valuable salts from used beverage cans (UBCs). The suggested method updated the current recycling technology by augmenting removal of the coating paint, decreasing magnesium loss during melting process and improving hydrochloric acid leaching of the formed slag. Iron impurity present in the leaching solution, was removed by oxidation using oxygen gas or hydrogen peroxide and filtered as goethite. Results obtained revealed that a mixture of methyl ethyl ketone/dimethyl formamide entirely removes the paint coating at room temperature. The process compares favorably to the current methods involving firing or swell peeling. The coating decomposes to titanium dioxide by heating at 750 degrees C for 30 min. Standard compositions of Al-Mg alloys are formulated using secondary magnesium. The extent of recovery (R) of these alloy(s) is a function of the melting time and temperature and type of the flux. The maximum (R) value amounts to 94.4%. Sodium borate/chloride mix decreases magnesium loss to a minimum. The extent of leaching valuable salts from the slag increases with increasing the molarity, stoichiometric ratio and leaching temperature of the acid used. Removal of iron is a function of the potential of the oxidation process. Stannous chloride has been recovered from the recovered and dried salts by distillation at 700-750 degrees C.

  4. Influence of Process Parameters on the Quality of Aluminium Alloy EN AW 7075 Using Selective Laser Melting (SLM)

    NASA Astrophysics Data System (ADS)

    Kaufmann, N.; Imran, M.; Wischeropp, T. M.; Emmelmann, C.; Siddique, S.; Walther, F.

    Selective laser melting (SLM) is an additive manufacturing process, forming the desired geometry by selective layer fusion of powder material. Unlike conventional manufacturing processes, highly complex parts can be manufactured with high accuracy and little post processing. Currently, different steel, aluminium, titanium and nickel-based alloys have been successfully processed; however, high strength aluminium alloy EN AW 7075 has not been processed with satisfying quality. The main focus of the investigation is to develop the SLM process for the wide used aluminium alloy EN AW 7075. Before process development, the gas-atomized powder material was characterized in terms of statistical distribution: size and shape. A wide range of process parameters were selected to optimize the process in terms of optimum volume density. The investigations resulted in a relative density of over 99%. However, all laser-melted parts exhibit hot cracks which typically appear in aluminium alloy EN AW 7075 during the welding process. Furthermore the influence of processing parameters on the chemical composition of the selected alloy was determined.

  5. PALS determination of defect density within friction stir welded joints of aluminium alloys

    NASA Astrophysics Data System (ADS)

    Kansy, J.; Mroczka, K.; Dutkiewicz, J.

    2011-01-01

    Positron annihilation spectroscopy is employed to investigate the density of defects in samples of aluminium alloys (2017 A and 6013) welded using the Friction Stir Welding method. The vacancy and dislocation densities were determined at the weld junction as a function of various parameters and conditions: Travel and rotational speed of welding tool, cooling of the surface of the welded material and the compositions of the welded alloys. The 3-state trapping model used in the computer analysis allowed to separate a vacancy component from a component related to dislocations. The determined lifetime of positron trapped by dislocation was much shorter than its experimental values referred to in literature, however, it is closer to the theoretical predictions.

  6. Physically-based constitutive modelling of residual stress development in welding of aluminium alloy 2024

    SciTech Connect

    Preston, R.V.; Shercliff, H.R. . E-mail: hrs@eng.cam.ac.uk; Withers, P.J.; Smith, S.

    2004-10-04

    A finite element model has been developed to predict the evolution of residual stress and distortion which takes into account the history-dependence of the yield stress-temperature response of heat-treatable aluminium alloys during welding. The model was applied to TIG welding of 2024-T3 aluminium alloy, and the residual strain predictions validated using high resolution X-ray synchrotron diffraction. The goal was to capture the influence of the permanent evolution of the microstructure during the thermal cycle with a straightforward numerical procedure, while retaining a sound physical basis. Hardness and resistivity measurements after isothermal hold-and-quench experiments were used to identify salient temperatures for zero, partial and full dissolution of the initial hardening precipitates, and the extent of softening - both immediately after welding, and after natural ageing. Based on these data, a numerical procedure for weld modelling was proposed for tracking the different yield responses during heating and cooling based on the peak temperature reached locally. This history-dependent model was superior to a conventional model in predicting the peak tensile strains, but otherwise the effect of temperature history was weak for 2024-T3. Predictions of the hardness profile immediately after welding compared with the post-weld naturally aged hardness provided insight into the competition between dissolution and coarsening of the precipitates in the heat-affected zone.

  7. On the optimisation of machining parameters for dry drilling of aeronautic aluminium alloy

    NASA Astrophysics Data System (ADS)

    List, G.; Girot, F.

    2003-09-01

    Machining aluminium alloys without lubrication seriously increases the tool wear because of the severe tribological conditions at the tool/chip interface. Indeed, metal cutting generates high temperatures and pressures due to the high strain rate (ge104 s^{-1}) and the friction between the tool and the chip. Thus, it is very important to be able to clearly identify the parameters influencing the machining quality. In order to study dry drilling with W-Co carbide tools, experiments were conducted using different drill geometries and varying cutting conditions. The workpiece material used in this work is the aluminium alloy 2024 T-351. Optimise drill geometries can be deducted from experimental results to obtain holes with an aerospace quality. The following parameters were used to evaluate the holes quality : the minimum and maximum diameter deviations, the burr height and the surface roughness. The microscope observation of the tool rake face shows that the main damage is adhesion and diffusion wear revealing the presence of high temperature. Cutting conditions were tested and chosen to limit the tool damage and by consequence to increase the tool life.

  8. Determination of aluminium in molybdenum and tungsten metals, iron, steel and ferrous and non-ferrous alloys with pyrocatechol violet.

    PubMed

    Donaldson, E M

    1971-09-01

    A method for determining 0.001-0.10% of aluminium in molybdenum and tungsten metals is described. After sample dissolution, aluminium is separated from the matrix materials by chloroform extraction of its acetylacetone complex, at pH 6.5, from an ammonium acetate-hydrogen peroxide medium, then back-extracted into 12M hydrochloric add. Following separation of most co-extracted elements, except for beryllium and small amounts of chroinium(III) and copper(II), by a combined ammonium pyrrolidincdithiocarbamate-cupfen-on-chlorofonn extraction, aluminium is determined spectrophotometrically with Pyrocatechol Violet at 578 nm. Chromium interferes during colour development but beryllium, in amounts equivalent to the aluminium concentration, does not cause significant error in the results. Interference from copper(II) is eliminated by reduction with ascorbic acid. The proposed method is also applicable to iron, steel, ferrovanadium, and copper-base alloys after preliminary removal of the matrix elements by a mercury cathode separation.

  9. Effect of pulsed current GTA welding parameters on the fusion zone microstructure of AA 6061 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Kumar, T. Senthil; Balasubramanian, V.; Babu, S.; Sanavullah, M. Y.

    2007-08-01

    AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of food processing equipment, chemical containers, passenger cars, road tankers, and railway transport systems. The preferred process for welding these aluminium alloys is frequently Gas Tungsten Arc (GTA) welding due to its comparatively easy applicability and lower cost. In the case of single pass GTA welding of thinner sections of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current processes. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. In this investigation, an attempt has been made to develop a mathematical model to predict the fusion zone grain diameter incorporating pulsed current welding parameters. Statistical tools such as design of experiments, analysis of variance, and regression analysis are used to develop the mathematical model. The developed model can be effectively used to predict the fusion grain diameter at a 95% confidence level for the given pulsed current parameters. The effect of pulsed current GTA welding parameters on the fusion zone grain diameter of AA 6061 aluminium alloy welds is reported in this paper.

  10. The effect of strain rate on the evolution of microstructure in aluminium alloys.

    PubMed

    Leszczyńska-Madej, B; Richert, M

    2010-03-01

    Intensive deformations influence strongly microstructure. The very well-known phenomenon is the diminishing dimension of grain size by the severe plastic deformation (SPD) methods. The nanometric features of microstructure were discovered after the SPD deformation of various materials, such as aluminium alloys, iron and others. The observed changes depended on the kind of the deformed material, amount of deformation, strain rate, existence of different phases and stacking fault energy. The influence of the strain and strain rate on the microstructure is commonly investigated nowadays. It was found that the high strain rates activate deformation in shear bands, microbands and adiabatic shear bands. It was observed that bands were places of the nucleation of nanograins in the material deformed by SPD methods. In the work, the refinement of microstructure of the aluminium alloys influenced by the high strain rate was investigated. The samples were compressed by a specially designed hammer to the deformation of phi= 0/0.62 with the strain rate in the range of [Formula in text]. The highest reduction of microbands width with the increase of the strain was found in the AlCu4Zr alloy. The influence of the strain rate on the microstructure refinement indicated that the increase of the strain rate caused the reduction of the microbands width in the all investigated materials (Al99.5, AlCu4Zr, AlMg5, AlZn6Mg2.5CuZr). A characteristic feature of the microstructure of the compressed material was large density of the shear bands and microbands. It was found that the microbands show a large misorientation to the surrounds and, except Al99.5, the large density of dislocation.

  11. Dual wavelength laser beam alloying of aluminium alloy for enhanced corrosion resistance

    SciTech Connect

    Liu, Z.; Watkins, K.G.; Steen, W.M.; Vilar, R.; Ferreira, M.G.

    1997-08-01

    Aluminum alloys are known for their poor resistance to localized attack and, in particular, for pitting in chloride-containing electrolytes. In this paper, improvement of the pitting corrosion resistance of 2014-T6 aluminum alloy has been investigated by means of laser surface alloying of Cr into the substrate. Since aluminum is highly reflective and thermally conductive material, it is often difficult to process with laser beams. Oxide films on the surface can prevent surface alloying as with the case of Cr alloying into aluminum by in-situ powder feeding. This work describes a new technique using mixed excimer laser and CO{sub 2} laser beam processing to generate a Cr alloyed layer on a 2014 aluminum alloy substrate. It is shown that improvement of alloying homogeneity following in-situ powder feeding can be achieved with mixed beam processing. Conditions under which this can be achieved have been studied and the effect of laser processing parameters on the surface roughness, oxidation and absorption is discussed. Microstructural and surface morphological analysis using optical microscopy, scanning electron microscopy and energy dispersive spectroscopy are also discussed. The electrochemical behavior of the treated samples in de-aerated 1 M NaCl solution has also been studied and has indicated that an improvement of pitting resistance by laser surface treatment can be achieved.

  12. Electrochemical characteristics of a carbon fibre composite and the associated galvanic effects with aluminium alloys

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Curioni, M.; Jamshidi, P.; Walker, A.; Prengnell, P.; Thompson, G. E.; Skeldon, P.

    2014-09-01

    The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO4 electrolytes was examined by potentiodynamic polarisation, potentiostatic polarisation and scanning electron microscopy. Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation. The large size of the exposed carbon fibres on the side region is responsible for a higher cathodic current density than the front region in the NaCl electrolyte. The deposition of copper on the front surface of composite confirmed that the significantly higher cathodic current resulted from the exposure of the fibres to the NaCl electrolyte. Galvanic coupling between the composite and individual aluminium alloys (AA7075-T6 and AA1050) was used to measure galvanic potentials and galvanic current densities. The highly alloyed AA7075-T6 alloy and its high population density of cathodic sites compared to the AA1050 acted to reduce the galvanic effect when coupled to the composite front or side regions.

  13. Characterisation of the anodic layers formed on 2024 aluminium alloy, in tetraborate electrolyte containing molybdate ions

    NASA Astrophysics Data System (ADS)

    Moutarlier, V.; Pelletier, S.; Lallemand, F.; Gigandet, M. P.; Mekhalif, Z.

    2005-12-01

    Anodic layer growth on 2024 aluminium alloy at 70 °C, under 40 V, during 60 min, in 50 g L -1 di-sodium tetraborate solution containing di-sodium molybdate from 0.1 to 0.5 M (pH 10) is examined. Anodising behaviours strongly depend on additive concentration. Development of anodic films is favoured with weak molybdate additions (<0.3-0.4 M). The film thicknesses increase and the porosity of anodic layers decreases. Molybdenum (+VI), detected by X-ray photoelectron spectroscopy (XPS) analysis, is present in the anodic films and the Mo incorporation, studied by energy dispersive spectroscopy (EDS) analysis, increases with molybdate concentration. However, for high molybdate concentrations (>0.4 M), anodising behaviour becomes complex with the formation of a blue molybdenum oxide at the cathode. The growth of aluminium oxide is hindered. As the anodic layers are thinner, the Mo(+VI) incorporation significantly decreases. These two configurations implicate different corrosion performances in 5% sodium chloride solution at 35 °C. As the alkaline anodic layer formed with 0.3 M molybdate species is the thickest and the Mo incorporation is the more pronounced, its corrosion resistance is the highest. The effect of morphology and composition of anodic films on pitting corrosion is also discussed.

  14. Influence of rotary swaging and subsequent age hardening on properties of EN AW 6082 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Maleček, L.; Palán, J.; Nacházel, J.; Dlouhý, J.

    2017-02-01

    Mechanical properties and microstructure of EN AW 6082 were investigated. The aluminium alloy was processed by combining the solution annealing, plastic deformation and artificial age hardening, respectively. The initial state of the investigated material was provided in the form of extruded rods with the diameter of 12 mm. For the solution annealing the temperature 530 °C was chosen. The plastic deformation was realized by rotary swaging at ambient temperature and the investigated material was rotary swaged from 12 to 10 mm in diameter. The effect of the age hardening temperature and time was studied at temperatures of 120 and 160 °C and times 1 - 12 hours. The impact of processing parameters on mechanical properties was assessed by tensile testing and hardness measurement. Metallographic examination was carried out by light optical microscopy (LOM) and scanning electron microscopy using electron backscatter diffraction (SEM-EBSD).

  15. Experimental study of thermal oxidation of nanoscale alloys of aluminium and zinc (nAlZn)

    NASA Astrophysics Data System (ADS)

    Noor, Fahad; Wen, Dongsheng

    2015-10-01

    Aluminium-based alloys have wide applications but little is known about the thermal-chemical kinetics of nanoalloys. This work investigated the thermal oxidation of Zn and Al nanoalloys (nAlZn) with a BET equivalent diameter of 141 nm through the simultaneous TGA/DSC method. The thermal analysis was combined with elemental, morphology and crystalline structure analysis to elucidate the reaction mechanisms. It was found that the complete oxidation of nAlZn in air can be characterised by a three-stage process, including two endothermic and three exothermic reactions. With the help of ex-situ XRD, different reaction pathways were proposed for different stages, forming the end products of ZnO and ZnAl2O4. The reactivity comparison between Al and nAlZn suggested that different criteria should be used for different applications.

  16. Effect of stress relieving treatment on low cycle fatigue behavior of USSP treated 7075 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Pandey, Vaibhav; Chattopadhyay, K.; Santhi Srinivas, N. C.; Singh, Vakil

    2017-05-01

    The effect of ultrasonic shot peening (USSP) on low cycle fatigue (LCF) behavior of the 7075 aluminium alloy was studied at room temperature. There was grain refinement approximately to 20 nm size, appreciable increase in micro hardness, and inducement of residual compressive stress in the surface region, due to the USSP treatment. The modified microstructure in surface region of the specimens subjected to USSP was characterized by X-ray diffraction and transmission electron microscopy. There was marked increase in LCF life of the specimens due to USSP, however, LCF life of the USSP specimens was reduced due to subsequent treatment of stress relieving. The results are discussed in terms of the process of crack initiation and propagation in the different conditions.

  17. Investigation of dynamic dry friction between stainless steel and aluminium alloy

    NASA Astrophysics Data System (ADS)

    Keightley, Peter; Winter, Ron; Stirk, Stewart

    2009-06-01

    Previous workers studied dynamic friction by using an impacting copper plate to drive a tapered aluminium alloy plug into a matching hole in a stainless steel outer sheath. The velocity of the back surface of the plug was measured using velocity interferometry. We have performed experiments on a version of this basic configuration that has been enlarged so that the sliding surfaces remain in contact for a longer time than with the original configuration. By comparing our results with computer simulations we conclude that the frictional forces between the inner cone and the steel outer are initially high but decrease significantly as the sliding proceeds. This effect is assumed to result from thermal softening of the material at the sliding interface. The study is supported by metallography of the recovered components.

  18. Experimental characterisation and modelling of deformation- induced microstructure in an A6061 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Kreyca, J. F.; Falahati, A.; Kozeschnik, E.

    2016-03-01

    For industry, the mechanical properties of a material in form of flow curves are essential input data for finite element simulations. Current practice is to obtain flow curves experimentally and to apply fitting procedures to obtain constitutive equations that describe the material response to external loading as a function of temperature and strain rate. Unfortunately, the experimental procedure for characterizing flow curves is complex and expensive, which is why the prediction of flow-curves by computer modelling becomes increasingly important. In the present work, we introduce a state parameter based model that is capable of predicting the flow curves of an A6061 aluminium alloy in different heat-treatment conditions. The model is implemented in the thermo-kinetic software package MatCalc and takes into account precipitation kinetics, subgrain formation, dynamic recovery by spontaneous annihilation and dislocation climb. To validate the simulation results, a series of compression tests is performed on the thermo-mechanical simulator Gleeble 1500.

  19. Microstructure of friction stir welded joints of 2017A aluminium alloy sheets.

    PubMed

    Mroczka, K; Dutkiewicz, J; Pietras, A

    2010-03-01

    The present study examines a friction stir welded 2017A aluminium alloy. Transmission electron microscope investigations of the weld nugget revealed the average grain size of 5 microm, moderate density of dislocations as well as the presence of nanometric precipitates located mostly in grains interiors. Scanning electron microscope observations of fractures showed the presence of ductile fracture in the region of the weld nugget with brittle precipitates in the lower part. The microhardness analysis performed on the cross-section of the joints showed fairly small changes; however, after the artificial ageing process an increase in hardness was observed. The change of the joint hardness subject to the ageing process indicates partial supersaturation in the material during friction stir welding and higher precipitation hardening of the joint.

  20. Material Characterization of Dissimilar Friction Stir Spot Welded Aluminium and Copper Alloy

    NASA Astrophysics Data System (ADS)

    Sanusi, K. O.; Akinlabi, E. T.

    2017-08-01

    In this research study, material characterization of dissimilar friction stir spot welded Aluminium and Copper was evaluated. Rotational speeds of 800 rpm and transverse speeds of 50 mm/min, 150 mm/min and 250 mm/min were used. The total numbers of samples evaluated were nine altogether. The spot welds were characterised by microstructure characterization using optical microscope (OEM) and scanning electron microscopy technique (SEM) by observing the evolution of the microstructure across the weld’s cross-section. lap-shear test of the of the spot weld specimens were also done. From the results, it shows that welding of metals and alloys using Friction stir spot welding is appropriate and can be use in industrial applications.

  1. The influence of uniaxial prestrain on biaxial r-values in 7075-O aluminium alloy

    SciTech Connect

    Anderson, N.; Brown, D.; McMurray, R. J.; Leacock, A. G.

    2011-05-04

    Biaxial test methods have been used to determine, not only yield behaviour under biaxial conditions, but also the strain response. This paper examines the influence of uniaxial prestrain upon the biaxial r-value by extending the disc compression test procedure proposed by Barlat et al. The extension involved the use of digital image measurements of in-plane strains. The material examined was a 7075-O condition aluminium alloy. The results of the experimental programme indicated that the biaxial r-value is unaffected by uniaxial prestrain. When using the disc compression test, the mode of deformation and therefore the biaxial r-value were found to be very sensitive to the prevailing friction conditions.

  2. The influence of uniaxial prestrain on biaxial r-values in 7075-O aluminium alloy

    NASA Astrophysics Data System (ADS)

    Anderson, N.; Brown, D.; McMurray, R. J.; Leacock, A. G.

    2011-05-01

    Biaxial test methods have been used to determine, not only yield behaviour under biaxial conditions, but also the strain response. This paper examines the influence of uniaxial prestrain upon the biaxial r-value by extending the disc compression test procedure proposed by Barlat et al. [1]. The extension involved the use of digital image measurements of in-plane strains. The material examined was a 7075-O condition aluminium alloy. The results of the experimental programme indicated that the biaxial r-value is unaffected by uniaxial prestrain. When using the disc compression test, the mode of deformation and therefore the biaxial r-value were found to be very sensitive to the prevailing friction conditions.

  3. Strain rate effects on mechanical properties in tension of aluminium alloys used in armour applications

    NASA Astrophysics Data System (ADS)

    Cadoni, E.; Dotta, M.; Forni, D.; Bianchi, S.; Kaufmann, H.

    2012-08-01

    The mechanical properties in tension of two aluminium alloys (AA5059-H131 and AA7039-T651) used in armour applications were determined from tests carried out over a wide range of strain-rates on round specimens. The experimental research was developed in the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. The target strain rates were set at the following four levels: 10-3, 30, 300 and 1000s-1. The quasi-static tests were performed with a universal electromechanical machine, whereas a hydro-pneumatic machine and a Split Hopkinson Tensile Bar apparatus were used for medium and high strain-rates respectively. The required parameters by the Johnson-Cook constitutive law were also determined.

  4. Optimization of process parameters in CNC turning of aluminium alloy using hybrid RSM cum TLBO approach

    NASA Astrophysics Data System (ADS)

    Rudrapati, R.; Sahoo, P.; Bandyopadhyay, A.

    2016-09-01

    The main aim of the present work is to analyse the significance of turning parameters on surface roughness in computer numerically controlled (CNC) turning operation while machining of aluminium alloy material. Spindle speed, feed rate and depth of cut have been considered as machining parameters. Experimental runs have been conducted as per Box-Behnken design method. After experimentation, surface roughness is measured by using stylus profile meter. Factor effects have been studied through analysis of variance. Mathematical modelling has been done by response surface methodology, to made relationships between the input parameters and output response. Finally, process optimization has been made by teaching learning based optimization (TLBO) algorithm. Predicted turning condition has been validated through confirmatory experiment.

  5. Flow and failure of an aluminium alloy from low to high temperature and strain rate

    NASA Astrophysics Data System (ADS)

    Sancho, Rafael; Cendón, David; Gálvez, Francisco

    2015-09-01

    The mechanical behaviour of an aluminium alloy is presented in this paper. The study has been carried out to analyse the flow and failure of the aluminium alloy 7075-T73. An experimental study has been planned performing tests of un-notched and notched tensile specimens at low strain rates using a servo-hydraulic machine. High strain rate tests have been carried out using the same geometry in a Hopkinson Split Tensile Bar. The dynamic experiments at low temperature were performed using a cryogenic chamber, and the high temperature ones with a furnace, both incorporated to the Hopkinson bar. Testing temperatures ranged from - 50 ∘C to 100 ∘C and the strain rates from 10-4 s-1 to 600 s-1. The material behaviour was modelled using the Modified Johnson-Cook model and simulated using LS-DYNA. The results show that the Voce type of strain hardening is the most accurate for this material, while the traditional Johnson-Cook is not enough accurate to reproduce the necking of un-notched specimens. The failure criterion was obtained by means of the numerical simulations using the analysis of the stress triaxiality versus the strain to failure. The diameters at the failure time were measured using the images taken with an image camera, and the strain to failure was computed for un-notched and notched specimens. The numerical simulations show that the analysis of the evolution of the stress triaxiality is crucial to achieve accurate results. A material model using the Modified Johnson-Cook for flow and failure is proposed.

  6. Microstructures in the 6060 aluminium alloy after various severe plastic deformation treatments

    SciTech Connect

    Adamczyk-Cieslak, Boguslawa Mizera, Jaroslaw; Kurzydlowski, Krzysztof Jan

    2011-03-15

    This paper presents the results concerning the microstructural refinement of the industrial 6060 aluminium alloy processed by severe plastic deformation (SPD). The high level of plastic deformation was achieved using the three methods: hydrostatic extrusion (HE), equal channel angular extrusion (ECAE) and extrusion torsion (ET), which differed in the dynamics of the loading, intensity and homogeneity of the plastic strain field. Microstructure analyses were performed before and after SPD deformation using a transmission (TEM) and a scanning electron microscope (SEM). The refined microstructures were examined qualitatively and quantitatively by the stereological methods and computer image analyses. The microstructure of the industrial 6060 aluminium alloy after deformation was characterized by an average grain size of about 0.4 {mu}m. The results show that the precipitates strongly affect the degree of refinement and the mechanism of microstructural transformations. During the SPD, the second phase particles break apart and homogenize. The HE method generates the largest increase of the volume fraction of the small primary particles. Moreover, the HE process is most effective in reducing the primary particle size. During HE and ECAE processes the second phase precipitates dissolve partially and change their shape. - Research Highlights: {yields} SPD results in a significant increase in the density of the small primary particles. {yields} SPD homogenizes the particle size distribution. {yields} HE and ECAE processes bring nano-grains in the vicinity of the primary particles. {yields} HE and ECAE processing results in the {beta}' precipitates partial dissolutions. {yields} During HE and ECAE processes the {beta}' particles change their shape.

  7. Influences of post weld heat treatment on tensile properties of friction stir welded AA2519-T87 aluminium alloy joints

    NASA Astrophysics Data System (ADS)

    Sabari, S. Sree; Balasubramanian, V.; Malarvizhi, S.; Reddy, G. Madusudhan

    2015-12-01

    AA 2519-T87 is an aluminium alloy that principally contains Cu as an alloying element and is a new grade of Al-Cu alloy system. This material is a potential candidate for light combat military vehicles. Fusion welding of this alloy leads to hot cracking, porosity and alloy segregation in the weld metal region. Friction stir welding (FSW) is a solid state joining process which can overcome the above mentioned problems. However, the FSW of age hardenable aluminium alloys results in poor tensile properties in the as-welded condition (AW). Hence, post weld heat treatment (PWHT) is used to enhance deteriorated tensile properties of FSW joints. In this work, the effect of PWHT, namely artificial ageing (AA) and solution treatment (ST) followed by ageing (STA) on the microstructure, tensile properties and microhardness were systematically investigated. The microstructural features of the weld joints were characterised using an optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The tensile strength and microhardness of the joints were correlated with the grain size, precipitate size, shape and its distribution. From the investigation, it was found that STA treatment is beneficial in enhancing the tensile strength of the FSW joints of AA2519-T87 alloy and this is mainly due to the presence of fine and densely distributed precipitates in the stir zone.

  8. A survey of some metallographic etching reagents for restoration of obliterated engraved marks on aluminium-silicon alloy surfaces.

    PubMed

    Uli, Norjaidi; Kuppuswamy, R; Amran, Mohd Firdaus Che

    2011-05-20

    A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al-Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO(3) on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO(3) containing 10-20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al-Zn-Mg-Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al-Zn-Mg-Cu alloys [23] were quite ineffective on Al-Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al-Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy.

  9. The Effect of Some Water-Displacing Corrosion Preventives on Corrosion of Aluminium Alloys 7075-T651 and 2024-T6,

    DTIC Science & Technology

    1983-08-01

    AIR 82/138 4. Title 5. Security 6. No. Pages THE EFFECT OF SOME WATER- DISPLACING a. document 8 CORROSION PREVENTIVES ON CORROSION Unclassifiedb. title...LABORATORIES MELBOURNE, VICTORIA MATERIALS REPORT 115 THE EFFECT OF SOME WATER- DISPLACING CORROSION PREVENTIVES ON CORROSION OF ALUMINIUM ALLOYS 7075-T651 AND... DISPLACING CORROSION PREVENTIVES ON CORROSION OF ALUMINIUM ALLOYS 7075-T651 AND 2024-T6 by L. WILSON and R. S. G. DEVEREUX SUMMARY The effectiveness

  10. The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

    SciTech Connect

    Robinson, J.S.; Tanner, D.A.; Truman, C.E.; Paradowska, A.M.; Wimpory, R.C.

    2012-03-15

    The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010. - Highlights: Black-Right-Pointing-Pointer Through thickness residual stress measurements made on large Al alloy forgings. Black-Right-Pointing-Pointer Residual stress characterised using neutron diffraction and deep hole drilling. Black-Right-Pointing-Pointer Biaxial compressive surface and triaxial subsurface residual stresses. Black-Right-Pointing-Pointer Quench sensitivity

  11. A microstructure-based yield stress and work-hardening model for textured 6xxx aluminium alloys

    NASA Astrophysics Data System (ADS)

    Khadyko, M.; Myhr, O. R.; Dumoulin, S.; Hopperstad, O. S.

    2016-04-01

    The plastic properties of an aluminium alloy are defined by its microstructure. The most important factors are the presence of alloying elements in the form of solid solution and precipitates of various sizes, and the crystallographic texture. A nanoscale model that predicts the work-hardening curves of 6xxx aluminium alloys was proposed by Myhr et al. The model predicts the solid solution concentration and the particle size distributions of different types of metastable precipitates from the chemical composition and thermal history of the alloy. The yield stress and the work hardening of the alloy are then determined from dislocation mechanics. The model was largely used for non-textured materials in previous studies. In this work, a crystal plasticity-based approach is proposed for the work hardening part of the nanoscale model, which allows including the influence of the crystallographic texture. The model is evaluated by comparison with experimental data from uniaxial tensile tests on two textured 6xxx alloys in five temper conditions.

  12. Large area laser surface treatment of aluminium alloys for pitting corrosion protection

    NASA Astrophysics Data System (ADS)

    Chong, P. H.; Liu, Z.; Skeldon, P.; Thompson, G. E.

    2003-03-01

    Laser surface treatment has been recognised as a useful method for corrosion protection of surfaces as a result of improved microstructure/phase formation and compositions. In large area applications, overlapping of individual tracks corresponding to the width of the laser beam is often necessary. This involves re-melting and re-heating of a portion of the previous track and results in microstructural changes, such as precipitate coarsening and microsegregation, which may influence localised corrosion at the overlapped regions. The purpose of this work is to investigate the influence of overlapped regions on corrosion behaviour of laser-melted aluminium 2014-T6 alloy. Laser melting was carried out using a 3 kW CW Nd:YAG laser with a line beam profile. The microstructures of the central part and the overlapped region of the melt pool were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Pitting corrosion resistance was evaluated using potentiodynamic anodic polarisation in 1 M NaCl solution. The work revealed enhancement of the pitting potential by 170 mV compared with that of the untreated alloy, similar to that achieved by laser surface melting with a CO 2 laser in a Gaussian mode. The line beam profile results in elimination of the planar front zones at the treated surface, but this benefit was offset by a coarser microstructure.

  13. Effect of heat treatments on mechanical properties and damage evolution of thixoformed aluminium alloys

    SciTech Connect

    Cavaliere, P. . E-mail: pasquale.cavaliere@unile.it; Cerri, E.; Leo, P.

    2005-07-15

    In the present work, the effects of heat treatments on mechanical properties, microstructure evolution and damage resulting from plastic deformation of thixoformed A319 and A356 aluminium alloys, are studied. The thixoforming process can lead to the production of components that are characterized by very good mechanical properties and low porosity with a globular microstructure which is fine and uniform. The mechanical properties can be further improved through heat treatments such as T5 and T6. The prime factor influencing the damage in the alloys belonging to the Al-Si system is represented by decohesion of silicon particles resulting from the stress concentration at the particle-matrix interfaces. A statistical analysis of fractured particles after tensile tests in the as-cast and as-treated condition has been carried out in the present work; optical and scanning electron microscopy techniques have been used to characterize the microstructure and fracture surfaces of the specimens and the results are fully presented.

  14. Distribution of trace elements in a modified and grain refined aluminium-silicon hypoeutectic alloy.

    PubMed

    Faraji, M; Katgerman, L

    2010-08-01

    The influence of modifier and grain refiner on the nucleation process of a commercial hypoeutectic Al-Si foundry alloy (A356) was investigated using optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis technique (EPMA). Filtering was used to improve the casting quality; however, it compromised the modification of silicon. Effect of filtering on strontium loss was also studied using the afore-mentioned techniques. EPMA was used to trace the modifying and grain refining agents inside matrix and eutectic Si. This was to help understanding mechanisms of nucleation and modification in this alloy. Using EPMA, the negative interaction of Sr and Al3TiB was closely examined. In modified structure, it was found that the maximum point of Sr concentration was in line with peak of silicon; however, in case of just 0.1wt% added Ti, the peak of Ti concentration was not in line with aluminium, (but it was close to Si peak). Furthermore, EPMA results showed that using filter during casting process lowered the strontium content, although produced a cleaner melt. (c) 2010 Elsevier Ltd. All rights reserved.

  15. Pulsed laser cleaning of aluminium-magnesium alloys: effect of surface modifications on adhesion

    NASA Astrophysics Data System (ADS)

    Autric, Michel; Oltra, Roland

    2008-05-01

    Surface cleaning is a key step in many industrial processes and especially in laser surface treatments. During laser cleaning of metallic alloys using pulsed lasers, surface modification can be induced due to transient thermal effect. In ambient atmospheric conditions, an oxidation of the cleaned surface can be detected. The aim of this work was to characterize this transient oxidation that can occur below the laser energy domain leading to any phase change (melting, ablation) of the cleaned substrate. A Q-switched Nd:YAG laser (1.06 μm) with 10 ns pulse duration was used for this study. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy were used for surface analysis of irradiated samples. Thermal oxidation took place on the aluminium-magnesium alloy (5000 series) during the irradiation in air (fluence range 0.6-1.4 Jcm-2). It has been demonstrated that this 10 ns laser thermal oxidation and the steady state thermal oxidation have the same mechanism. When the laser fluence reached 1 J cm -2 , the oxide formed by the thermal oxidation became in a large extent crystalline and its outer part was entirely covered by a continuous magnesium oxide layer.

  16. Zirconium behaviour during electrorefining of actinide-zirconium alloy in molten LiCl-KCl on aluminium cathodes

    NASA Astrophysics Data System (ADS)

    Meier, R.; Souček, P.; Malmbeck, R.; Krachler, M.; Rodrigues, A.; Claux, B.; Glatz, J.-P.; Fanghänel, Th.

    2016-04-01

    A pyrochemical electrorefining process for the recovery of actinides from metallic nuclear fuel based on actinide-zirconium alloys (An-Zr) in a molten salt is being investigated. In this process actinides are group-selectively recovered on solid aluminium cathodes as An-Al alloys using a LiCl-KCl eutectic melt at a temperature of 450 °C. In the present study the electrochemical behaviour of zirconium during electrorefining was investigated. The maximum amount of actinides that can be oxidised without anodic co-dissolution of zirconium was determined at a selected constant cathodic current density. The experiment consisted of three steps to assess the different stages of the electrorefining process, each of which employing a fresh aluminium cathode. The results indicate that almost a complete dissolution of the actinides without co-dissolution of zirconium is possible under the applied experimental conditions.

  17. New understanding of the role of coincidence site lattice boundaries in abnormal grain growth of aluminium alloy

    NASA Astrophysics Data System (ADS)

    Park, Chang-Soo; Park, Hyung-Ki; Shim, Hyung-Seok; Na, Tae-Wook; Han, Chan-Hee; Hwang, Nong-Moon

    2015-04-01

    The sequential microstructure evolution of abnormal grain growth (AGG) in the aluminium alloy (AA5052) was investigated to analyse the migration behaviour of coincidence site lattice (CSL) boundaries, which are known to play an important role in inducing AGG. The sequential evolution showed that CSL boundaries tend to disappear more slowly than general boundaries at the growth front of abnormally growing grains. Especially, the migration rate of Σ9 boundaries was noticeably low, which is contrary to the previous suggestions.

  18. Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating aluminium alloy plate

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Jin, Guangyong; Gu, Xiu-ying

    2014-12-01

    Based on Von Mises yield criterion and elasto-plastic constitutive equations, an axisymmetric finite element model of a Gaussian laser beam irradiating a metal substrate was established. In the model of finite element, the finite difference hybrid algorithm is used to solve the problem of transient temperature field and stress field. Taking nonlinear thermal and mechanical properties into account, transient distributions of temperature field and stress fields generated by the pulse train of long-pulse laser in a piece of aluminium alloy plate were computed by the model. Moreover,distributions as well as histories of temperature and stress fields were obtained. Finite element analysis software COMSOL is used to simulate the Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating 7A04 aluminium alloy plate. By the analysis of the results, it is found that Mises equivalent stress on the target surface distribute within the scope of the center of a certain radius. However, the stress is becoming smaller where far away from the center. Futhermore, the Mises equivalent stress almost does not effect on stress damage while the Mises equivalent stress is far less than the yield strength of aluminum alloy targets. Because of the good thermal conductivity of 7A04 aluminum alloy, thermal diffusion is extremely quick after laser irradiate. As a result, for the multi-pulsed laser, 7A04 aluminum alloy will not produce obvious temperature accumulation when the laser frequency is less than or equal to 10 Hz. The result of this paper provides theoretical foundation not only for research of theories of 7A04 aluminium alloy and its numerical simulation under laser radiation but also for long-pulse laser technology and widening its application scope.

  19. Simultaneous determination of lead, nickel, tin and copper in aluminium-base alloys using slurry sampling by electrical discharge and multielement ETAAS.

    PubMed

    Carrión, Nereida; Itriago, Ana M; Alvarez, Maria A; Eljuri, Elias

    2003-12-04

    The simultaneous multielement determination of Pb, Sn, Ni and Cu in aluminium alloys by electrothermal atomic absorption spectrometry (ETAAS) was performed by a quick method using slurry sampling. The metallic colloidal slurries were obtained by an electrical discharge operated in liquid medium. In this work, the effects of aluminium were evaluated and the results show that it causes a strong retention of Pb, Ni and Cu at low pyrolysis temperatures which is overcome by employing high pyrolysis temperatures. Aluminium also significantly improves the thermal stabilisation of Pb and Sn, it being possible to reach pyrolysis temperatures of 1100 and 1300 degrees C, respectively. Such stabilisation indicates that the performance of aluminium as a matrix modifier for Pb is better than that obtained using phosphate and magnesium nitrate without substantial changes of the figures of merit. The effects of aluminium on the atomisation characteristics of the elements and those coming from the simultaneous multielement determination on the figures of merit of the elements are also discussed. In this work, a calibration procedure involving a matrix matching method with aqueous aluminium standards is proposed as a simple and efficient way to solve the inconveniences originated by the aluminium matrix. The proposed method was applied to the simultaneous multielement determination of several aluminium-base alloy standards giving results well within the recommended values.

  20. Spectroscopic study of plasma during electrolytic oxidation of magnesium-aluminium alloys

    NASA Astrophysics Data System (ADS)

    Jovović, J.

    2014-12-01

    Plasma during Electrolytic Oxidation (PEO) of magnesium-aluminium alloys is studied in this work by means of Optical Emission Spectroscopy (OES). Spectral line shapes of the Hβ, Al II 704.21 nm and Mg II 448.11 nm line are analyzed to measure plasma electron number density Ne. From the Hβ line profile, two PEO processes characterized by relatively low electron number densities Ne ≈ 1015 cm-3 and Ne ≈ 2 × 1016 cm-3 were discovered while the shape and shift of Al II and Mg II lines revealed the third process characterized by large electron density Ne = (1-2) × 1017 cm-3. Low Ne processes, related with breakdown in gas bubbles and on oxide surface, are not influenced by anode material or electrolyte composition. The ejection of evaporated anode material through oxide layer is designated here as third PEO process. Using the Boltzmann plot technique, electron temperature of 4000 K and 33000 K is determined from relative intensities of Mg I and O II lines, respectively. Several difficulties in the analysis of spectral line shapes are met during this study and the ways to overcome some of the obstacles are demonstrated.

  1. Deep surface rolling for fatigue life enhancement of laser clad aircraft aluminium alloy

    NASA Astrophysics Data System (ADS)

    Zhuang, W.; Liu, Q.; Djugum, R.; Sharp, P. K.; Paradowska, A.

    2014-11-01

    Deep surface rolling can introduce deep compressive residual stresses into the surface of aircraft metallic structure to extend its fatigue life. To develop cost-effective aircraft structural repair technologies such as laser cladding, deep surface rolling was considered as an advanced post-repair surface enhancement technology. In this study, aluminium alloy 7075-T651 specimens with a blend-out region were first repaired using laser cladding technology. The surface of the laser cladding region was then treated by deep surface rolling. Fatigue testing was subsequently conducted for the laser clad, deep surface rolled and post-heat treated laser clad specimens. It was found that deep surface rolling can significantly improve the fatigue life in comparison with the laser clad baseline repair. In addition, three dimensional residual stresses were measured using neutron diffraction techniques. The results demonstrate that beneficial compressive residual stresses induced by deep surface rolling can reach considerable depths (more than 1.0 mm) below the laser clad surface.

  2. Constant and variable amplitude ultrasonic fatigue of 2024-T351 aluminium alloy at different load ratios.

    PubMed

    Mayer, H; Fitzka, M; Schuller, R

    2013-12-01

    Ultrasonic fatigue testing equipment is presented that is capable of performing constant amplitude (CA) and variable amplitude (VA) experiments at different constant load ratios. This equipment is used to study cyclic properties of aluminium alloy 2024-T351 in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime at load ratios R=-1 and R=0.5. CA loading does not reveal a fatigue limit below 10¹⁰ cycles. Cracks leading to VHCF failure start at broken constituent particles. Specimens that survived more than 10¹⁰ cycles at R=-1 contain non-propagating cracks of lengths below grain size. Resonance frequency and nonlinearity parameter β(rel) show changes of vibration properties of specimens at low fractions of their VHCF lifetime. VA lifetimes are measured in the HCF and VHCF regime and compared with Miner calculations. Damage sums decrease with decreasing load (and increasing mean lifetimes) and are lower for R=0.5 than R=-1.

  3. Strain Measurement in Aluminium Alloy during the Solidification Process Using Embedded Fibre Bragg Gratings

    PubMed Central

    Weraneck, Klaus; Heilmeier, Florian; Lindner, Markus; Graf, Moritz; Jakobi, Martin; Volk, Wolfram; Roths, Johannes; Koch, Alexander W.

    2016-01-01

    In recent years, the observation of the behaviour of components during the production process and over their life cycle is of increasing importance. Structural health monitoring, for example of carbon composites, is state-of-the-art research. The usage of Fibre Bragg Gratings (FBGs) in this field is of major advantage. Another possible area of application is in foundries. The internal state of melts during the solidification process is of particular interest. By using embedded FBGs, temperature and stress can be monitored during the process. In this work, FBGs were embedded in aluminium alloys in order to observe the occurring strain. Two different FBG positions were chosen in the mould in order to compare its dependence. It was shown that FBGs can withstand the solidification process, although a compression in the range of one percent was measured, which is in agreement with the literature value. Furthermore, different lengths of the gratings were applied, and it was shown that shorter gratings result in more accurate measurements. The obtained results prove that FBGs are applicable as sensors for temperatures up to 740 °C. PMID:27827900

  4. Design and Analysis of Wind Turbine Blade Hub using Aluminium Alloy AA 6061-T6

    NASA Astrophysics Data System (ADS)

    Ravikumar, S.; Jaswanthvenkatram, V.; Sai kumar, Y. J. N. V.; Sohaib, S. Md.

    2017-05-01

    This work presents the design and analysis of horizontal axis wind turbine blade hub using different material. The hub is very crucial part of the wind turbine, which experience the loads from the blades and the loads were transmitted to the main shaft. At present wind turbine is more expensive and weights more than a million pounds, with the nacelle, rotor hub and blades accounting for most of the weight. In this work Spheroidal graphite cast iron GGG 40.3 is replaced by aluminium alloy 6061-T6 to enhance the casting properties and also to improve the strength-weight ratio. This transition of material leads to reduction in weight of the wind turbine. All the loads caused by wind and extreme loads on the blades are transferred to the hub. Considering the IEC 61400-1 standard for defining extreme loads on the hub the stress and deflection were calculated on the hub by using Finite element Analysis. Result obtained from ANSYS is compared and discussed with the existing design.

  5. Strain Measurement in Aluminium Alloy during the Solidification Process Using Embedded Fibre Bragg Gratings.

    PubMed

    Weraneck, Klaus; Heilmeier, Florian; Lindner, Markus; Graf, Moritz; Jakobi, Martin; Volk, Wolfram; Roths, Johannes; Koch, Alexander W

    2016-11-04

    In recent years, the observation of the behaviour of components during the production process and over their life cycle is of increasing importance. Structural health monitoring, for example of carbon composites, is state-of-the-art research. The usage of Fibre Bragg Gratings (FBGs) in this field is of major advantage. Another possible area of application is in foundries. The internal state of melts during the solidification process is of particular interest. By using embedded FBGs, temperature and stress can be monitored during the process. In this work, FBGs were embedded in aluminium alloys in order to observe the occurring strain. Two different FBG positions were chosen in the mould in order to compare its dependence. It was shown that FBGs can withstand the solidification process, although a compression in the range of one percent was measured, which is in agreement with the literature value. Furthermore, different lengths of the gratings were applied, and it was shown that shorter gratings result in more accurate measurements. The obtained results prove that FBGs are applicable as sensors for temperatures up to 740 °C.

  6. Comparison of self-healing ionomer to aluminium-alloy bumpers for protecting spacecraft equipment from space debris impacts

    NASA Astrophysics Data System (ADS)

    Francesconi, A.; Giacomuzzo, C.; Grande, A. M.; Mudric, T.; Zaccariotto, M.; Etemadi, E.; Di Landro, L.; Galvanetto, U.

    2013-03-01

    This paper discusses the impact behavior of a self-healing ionomeric polymer and compares its protection capability against space debris impacts to that of simple aluminium-alloy bumpers. To this end, 14 impact experiments on both ionomer and Al-7075-T6 thin plates with similar surface density were made with 1.5 mm aluminium spheres at velocity between 1 and 4 km/s.First, the perforation extent in both materials was evaluated vis-à-vis the prediction of well known hole-size equations; then, attention was given to the damage potential of the cloud of fragments ejected from the rear side of the target by analysing the craters pattern and the momentum transferred to witness plates mounted on a ballistic pendulum behind the bumpers.Self-healing was completely successful in all but one ionomer samples and the primary damage on ionomeric polymers was found to be significantly lower than that on aluminium. On the other hand, aluminium plates exhibited slightly better debris fragmentation abilities, even though the protecting performance of ionomers seemed to improve at increasing impact speed.

  7. In-vitro characterization of stress corrosion cracking of aluminium-free magnesium alloys for temporary bio-implant applications.

    PubMed

    Choudhary, Lokesh; Singh Raman, R K; Hofstetter, Joelle; Uggowitzer, Peter J

    2014-09-01

    The complex interaction between physiological stresses and corrosive human body fluid may cause premature failure of metallic biomaterials due to the phenomenon of stress corrosion cracking. In this study, the susceptibility to stress corrosion cracking of biodegradable and aluminium-free magnesium alloys ZX50, WZ21 and WE43 was investigated by slow strain rate tensile testing in a simulated human body fluid. Slow strain rate tensile testing results indicated that each alloy was susceptible to stress corrosion cracking, and this was confirmed by fractographic features of transgranular and/or intergranular cracking. However, the variation in alloy susceptibility to stress corrosion cracking is explained on the basis of their electrochemical and microstructural characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Residual stresses in shape memory alloy fiber reinforced aluminium matrix composite

    NASA Astrophysics Data System (ADS)

    Tsz Loong, Tang; Jamian, Saifulnizan; Ismail, Al Emran; Nur, Nik Hisyammudin Muhd; Watanabe, Yoshimi

    2017-01-01

    Process-induced residual stress in shape memory alloy (SMA) fiber reinforced aluminum (Al) matrix composite was simulated by ANSYS APDL. The manufacturing process of the composite named as NiTi/Al is start with loading and unloading process of nickel titanium (NiTi) wire as SMA to generate a residual plastic strain. Then, this plastic deformed NiTi wire would be embedded into Al to become a composite. Lastly, the composite is heated form 289 K to 363 K and then cooled back to 300 K. Residual stress is generated in composite because of shape memory effect of NiTi and mismatch of thermal coefficient between NiTi wire and Al matrix of composite. ANSYS APDL has been used to simulate the distribution of residual stress and strain in this process. A sensitivity test has been done to determine the optimum number of nodes and elements used. Hence, the number of nodes and elements used are 15680 and 13680, respectively. Furthermore, the distribution of residual stress and strain of nickel fiber reinforced aluminium matrix composite (Ni/Al) and titanium fiber reinforced aluminium matrix composite (Ti/Al) under same simulation process also has been simulated by ANSYS APDL as comparison to NiTi/Al. The simulation results show that compressive residual stress is generated on Al matrix of Ni/Al, Ti/Al and NiTi/Al during heating and cooling process. Besides that, they also have similar trend of residual stress distribution but difference in term of value. For Ni/Al and Ti/Al, they are 0.4% difference on their maximum compressive residual stress at 363K. At same circumstance, NiTi/Al has higher residual stress value which is about 425% higher than Ni/Al and Ti/Al composite. This implies that shape memory effect of NiTi fiber reinforced in composite able to generated higher compressive residual stress in Al matrix, hence able to enhance tensile property of the composite.

  9. Influence of ECAP on Densification Behaviour in the PM Aluminium Al-Mg-Si-Cu-Fe Alloy

    NASA Astrophysics Data System (ADS)

    Bidulská, Jana; Kvačkaj, Tibor; Kočiško, Róbert; Bidulský, Róbert; Grande, Marco Actis

    2010-09-01

    The main aim of this paper is to show how ECAP influences the densification behaviour of PM aluminium alloys. An aluminium based powder (Al-Mg-Si-Cu-Fe) was used as material to be investigated. After applying different compacting pressures, specimens were dewaxed in a ventilated furnace at 400 °C for 60 min. Sintering was carried out in a vacuum furnace at 610 °C for 30 min. The specimens were ECAPed for 1 pass. Optical characterization was carried out on the minimum of 10 different image fields. The results were measured for each pore individually in order to describe the dimensional and morphological porosity characteristics. ECAP influences the porosity distribution in terms of the severe shear deformation involved.

  10. Tribological Properties of Aluminium Alloy Composites Reinforced with Multi-Layer Graphene-The Influence of Spark Plasma Texturing Process.

    PubMed

    Kostecki, Marek; Woźniak, Jarosław; Cygan, Tomasz; Petrus, Mateusz; Olszyna, Andrzej

    2017-08-10

    Self-lubricating composites are designed to obtain materials that reduce energy consumption, improve heat dissipation between moving bodies, and eliminate the need for external lubricants. The use of a solid lubricant in bulk composite material always involves a significant reduction in its mechanical properties, which is usually not an optimal solution. The growing interest in multilayer graphene (MLG), characterised by interesting properties as a component of composites, encouraged the authors to use it as an alternative solid lubricant in aluminium matrix composites instead of graphite. Aluminium alloy 6061 matrix composite reinforced with 2-15 vol % of MLG were synthesised by the spark plasma sintering process (SPS) and its modification, spark plasma texturing (SPT), involving deformation of the pre-sintered body in a larger diameter matrix. It was found that the application of the SPT method improves the density and hardness of the composites, resulting in improved tribological properties, particularly in the higher load regime.

  11. Laser surface melting of aluminium alloy 6013 for improving stress corrosion and corrosion fatigue resistance

    NASA Astrophysics Data System (ADS)

    Xu, Wen-Long

    Laser surface treatment of aluminium alloy 6013, a relatively new high strength aluminium alloy, was conducted with the aim of improving the alloy's resistance to stress corrosion cracking and corrosion fatigue. In the first phase of this research, laser surface melting (LSM) of the alloy was conducted using an excimer laser. The microstructural changes induced by the laser treatment were studied in detail and characterised. The results showed that excimer LSM produced a relatively thin, non-dentritic planar re-melted layer which is largely free of coarse constituent particles and precipitates. The planar growth phenomenon was explained using the high velocity and high temperature gradient absolute stability criteria. The structure of the oxide and/or the nitride bearing film at the outmost surface of the re-melted layer was also characterised. The results of the electrochemical tests showed that the pitting corrosion resistance of the alloy could be greatly increased by excimer laser melting, especially when the alloy was treated in nitrogen gas: the corrosion current density of the N2-treated specimen was some two orders of magnitude lower than that of the air-treated specimen which was one order of magnitude lower than that of the untreated specimen. The effect of the outer surface oxide and/or nitride bearing film per se on pitting corrosion resistance was determined. The results of a Mott - Schottky analysis strongly suggest that the outer surface film, which exhibited the nature of an n-type semiconductor was responsible for the significant improvement of the corrosion resistance of the laser-treated material. Furthermore, the corrosion response of the surface film was modelled using equivalent circuits. Based on the results of the slow strain rate tensile (SSRT) and corrosion fatigue tests, the stress corrosion cracking and pitting corrosion fatigue behaviour of the excimer laser treated material was evaluated. The results of the SSRT test showed that, in

  12. Effects of processing parameters on laser cutting of aluminium-copper alloys using off-axial supersonic nozzles

    NASA Astrophysics Data System (ADS)

    Riveiro, A.; Quintero, F.; Lusquiños, F.; Comesaña, R.; Pou, J.

    2011-04-01

    Conventional laser cutting involves the utilization of converging coaxial nozzles to inject the assist gas used to remove the molten material. This processing system prevents the utilization of this technique to cut aluminium alloys for aerospace applications. The inefficient removal of molten material by the assist gas produces cuts with poor quality; very rough cuts, with a large amount of dross, and a large heat affected zone (HAZ) are obtained. An alternative to increase the assist gas performance is the utilization of off-axial supersonic nozzles. Removal of molten material is substantially increased and cuts with high quality are obtained. On the other hand, pulsed laser cutting offers superior results during the processing of high reflectivity materials as aluminium alloys. However, there are no experimental studies which explore the pulsed laser cutting of aluminium alloys by means of a cutting head assisted by an off-axis supersonic nozzle. The present work constitutes a quantitative experimental study to determine the influence of processing parameters on the cutting speed and quality criteria during processing by means of off-axial supersonic nozzles. Cutting experiments were performed in pulsed mode and the results explained under the basis of the molten material removal mechanisms. Performed experiments indicate a reduction in cutting speed as compared to continuous wave (CW) mode processing and the existence of two processing regimes as a function of the pulse frequency. Best results are obtained under the high pulse frequency one ( f > 100 Hz) because the superior capabilities of molten material removal of the supersonic jets are completely exploited in this processing regime.

  13. Electrodeposition of aluminium and aluminium-copper alloys from a room temperature ionic liquid electrolyte containing aluminium chloride and triethylamine hydrochloride

    NASA Astrophysics Data System (ADS)

    Suneesh, P. V.; Satheesh Babu, T. G.; Ramachandran, T.

    2013-09-01

    The electrodeposition of Al and Al-Cu binary alloys on to gold substrates from a room temperature ionic liquid electrolyte containing AlCl3-Et3NHCl was studied. The electrochemical behavior of the electrolyte and the mechanism of deposition were investigated through cyclic voltammetry (CV), and the properties of deposits obtained were assessed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray diffraction (XRD). Al of 70 μm in thickness and an Al-Cu alloy of 30 μm in thickness with 8at% copper were deposited from the electrolyte. SEM images of the deposits indicate that the Al deposit was smooth and uniform, whereas the Al-Cu deposit was nodular. The average crystalline size, as determined by XRD patterns, was found to be (30 ± 5) and (29 ± 5) nm, respectively, for Al and Al-Cu alloys. Potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopic (EIS) measurements showed that Al-Cu alloys are more corrosion resistant than Al.

  14. Determination of aluminium in iron, steel and ferrous and non-ferrous alloys by atomic-absorption spectrophotometry after a mercury-cathode separation and extraction of the aluminium-acetylacetone complex.

    PubMed

    Donaldson, E M

    1981-07-01

    A method for determining 0.0005% or more of total aluminium in high- and low-alloy steels, iron and ferrovanadium is described. Iron, chromium and other matrix elements are separated from aluminium by electrolysis with a mercury cathode and aluminium is separated from tungsten, titanium, vanadium and phosphate by chloroform extraction of its acetylacetone complex at pH 6.5 from an ammonium acetate-hydrogen peroxide medium. The extract is evaporated to dryness and organic material is destroyed with nitric and perchloric acids. Aluminium is determined by atomic-absorption spectrophotometry in a nitrous oxide-acetylene flame, at 309.3 nm, in a 5% v/v perchloric acid medium containing 1000 mug of sodium per ml. Acid-soluble and acid-insoluble aluminium can also be determined. The method is also applicable to copper- and nickel-base alloys. Results obtained by this method are compared with those obtained spectrophotometrically with Pyrocatechol Violet, after the separations described above followed by the separation of the residual co-extracted iron and copper by a combined ammonium pyrrolidinedithiocarbamate-cupferron-chloroform extraction from 10% v/v hydrochloric acid medium.

  15. Electromagnetic Gauge Study of Laser-Induced Shock Waves in Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Peyre, P.; Fabbro, R.

    1995-12-01

    The laser-shock behaviour of three industrial aluminum alloys has been analyzed with an Electromagnetic Gauge Method (EMV) for measuring the velocity of the back free surface of thin foils submitted to plane laser irradiation. Surface pressure, shock decay in depth and Hugoniot Elastic Limits (HEL) of the materials were investigated with increasing thicknesses of foils to be shocked. First, surface peak pressures values as a function of laser power density gave a good agreement with conventional piezoelectric quartz measurements. Therefore, comparison of experimental results with computer simulations, using a 1D hydrodynamic Lagrangian finite difference code, were also in good accordance. Lastly, HEL values were compared with static and dynamic compressive tests in order to estimate the effects of a very large range of strain rates (10^{-3} s^{-1} to 10^6 s^{-1}) on the mechanical properties of the alloys. Cet article fait la synthèse d'une étude récente sur la caractérisation du comportement sous choc-laser de trois alliages d'aluminium largement utilisés dans l'industrie à travers la méthode dite de la jauge électromagnétique. Cette méthode permet de mesurer les vitesses matérielles induites en face arrière de plaques d'épaisseurs variables par un impact laser. La mise en vitesse de plaques nous a permis, premièrement, de vérifier la validité des pressions d'impact superficielles obtenues en les comparant avec des résultats antérieurs obtenus par des mesures sur capteurs quartz. Sur des plaques d'épaisseurs croissantes, nous avons caractérisé l'atténuation des ondes de choc en profondeur dans les alliages étudiés et mesuré les limites d'élasticité sous choc (pressions d'Hugoniot) des alliages. Les résultats ont été comparés avec succès à des simulations numériques grâce à un code de calcul monodimensionnel Lagrangien. Enfin, les valeurs des pressions d'Hugoniot mesurées ont permis de tracer l'évolution des contraintes d

  16. Quasi-Static and Shock Induced Mechanical Response of an Aluminium-Zinc-Magnesium Alloy as a Function of Heat Treatment

    NASA Astrophysics Data System (ADS)

    Edwards, M. R.; Millett, J. C. F.; Bourne, N. K.

    2004-07-01

    Samples of an aluminium-zinc-magnesium alloy, typical of high strength weldable aluminium alloys, have been heat treated to produce two different microstructural conditions, these being peak-aged and under-aged. Mechanical tests have been performed, both at quasi-static strain rates and under shock loading conditions to determine how the mechanical properties change with heat treatment. Results indicate that the material has its highest strength when peak aged. Properties are discussed in relation to observed features within the microstructure, as recorded by optical and scanning electron microscopy.

  17. Experimental and numerical investigation of the residual yield strength of aluminium alloy EN AW-2024-T3 affected by artificially produced pitting corrosion

    NASA Astrophysics Data System (ADS)

    Pippig, R.; Schmidl, E.; Steinert, P.; Schubert, A.; Lampke, T.

    2017-03-01

    In this study, the behaviour of the residual yield strength of aluminium alloy EN AW-2024-T3 affected by the morphology and numbers of corrosion pits (defects) is presented. Since specific defect structures are not reproducible during experimental corrosion tests, metal sheets with different numbers of pits and pit shapes are produced using laser micro structuring. The defect structures are measured using laser scanning microscopy. To compare the stress states of the micro structured and real corroded metal sheets, FE-analysis is used. Afterwards, uniaxial tensile tests are carried out and critical defect parameters in terms of yield strength reduction of the investigated aluminium alloy are detected.

  18. Analysis Of The Surface Roughness Obtained During The Dry Turning Of UNS A97050-T7 Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    de Agustina, B.; Rubio, E. M.; Villeta, M.; Sebastián, M. A.

    2009-11-01

    Currently, in the aeronautical, aerospace and automotive industries there is high demand of materials such as the aluminium alloys that have high resistance even at high temperatures as well as a low density. For this reason, these alloys are widely used for the production of different elements that compose aircraft and aerospace vehicles. Nevertheless, in spite of the important role these materials have from the competitive point of view, they can commonly show problems of machinability associated with the tool wear. That has made that traditionally cutting fluids had been used in machining processes. However, they can contain environmentally harmful constituents and increase considerably the total cost of the process. Therefore, researches have been focused on the development of cleaner production technologies applications as dry machining. This leads to the search for combinations of cutting parameters and type of tools (types of coatings and different geometries) that could improve the machining under such conditions. The aim of this study is to analyse the relationship between the surface roughness obtained during the dry turning of aluminium UNS A97050-T7 bars and the cutting parameters (cutting speed and feed) using three different tools. As a first conclusion it could be affirmed that the feed was the cutting parameter more influential on the surface roughness and to a lesser extend the cutting speed, the type of tool and the interaction between the type of tool and the feed.

  19. The strain rate sensitivity and constitutive equations including damage for the superplastic behaviour of 7xxx aluminium alloys

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Boude, Serge; Giraud, Eliane; Dal Santo, Philippe

    2013-05-01

    Superplasticity is a characteristic of certain materials, in particular aluminium alloys, whereby very large deformations (up to 1000 %) can be obtained before fracture under certain conditions. Superplastic forming is therefore the process of deforming a flange under these conditions by applying a variable pressure. The final geometry is obtained when the flange takes the form of a die. In order to deform a material superplastically, the temperature of the material should be approximately a half of the absolute melting point of the material and the strain rate (or flow stress) should remain within a certain range. The most important issues concerning the industrial process are the prediction of the final thickness distribution and the computation of the optimal pressure law to maintain superplastic conditions. Finite element simulations make these predictions possible for industrial components. To ensure the precision of the simulations, it is important to have good knowledge of the material behaviour in the superplastic domain: rheological parameters, grain size, damage law, etc. This paper presents an experimental analysis of the superplastic behaviour of a 7xxx aluminium alloy used for aeronautic applications. The parameters of the constitutive equations (including damage) are identified by using tensile tests, spherical bulging tests and numerical simulations [1, 2]. The performance of the proposed laws [1, 3, and 4] is tested using axisymmetrical geometries with complex shapes by the comparison of numerical simulations and bulge tests.

  20. Contribution on Taguchi's Method Application on the Surface Roughness Analysis in End Milling Process on 7136 Aluminium Alloy

    NASA Astrophysics Data System (ADS)

    ȚÎȚU, M. A.; POP, A. B.

    2016-11-01

    The resulting surface quality after the cutting process is one of the most important characteristics of product quality and also the most frequent customer requirement. Previous research was focused on the effect investigation of machining parameters: cutting speed [1] and feed per tooth [2] on surface roughness. This paper is in itself a continuation of a previous research [3], in which, with Taguchi's method it was determined the level of influence of the cutting parameters on surface roughness of 7136 aluminium alloy in end milling process. The purpose of this paper is to highlight the importance of Taguchi's method use to analyse the surface roughness of 7136 aluminium alloy in end milling process. To conduct the experiments, three cutting parameters were used: cutting speed, feed per tooth and cutting depth. To analyse the surface quality, the surface roughness Ra (the arithmetic average of the absolute values) was measured. It was determined the recommended configuration regarding the optimum values of each machining parameter and the interactions between them, in order to obtain the better cutting process performance and to reduce the surface roughness sensitivity to uncontrollable factors. Based on a full factorial experiment were confirmed the obtained results by applying the Taguchi's method. Final results are a starting point for further research.

  1. Study of twin-roll cast Aluminium alloys subjected to severe plastic deformation by equal channel angular pressing

    NASA Astrophysics Data System (ADS)

    Poková, M.; Cieslar, M.

    2014-08-01

    Aluminium alloys prepared by twin-roll casting method become widely used in industry applications. Their high solid solution supersaturation and finer grains ensure better mechanical properties when compared with the direct-chill cast ones. One of the possibilities how to enhance their thermal stability is the addition of zirconium. After heat treatment Al3Zr precipitates form and these pin moving grain boundaries when the material is exposed to higher temperatures. In the present work twin-roll cast aluminium alloys based on AA3003 with and without Zr addition were annealed for 8 hours at 450 °C to enable precipitation of Al3Zr phase. Afterwards they were subjected to severe plastic deformation by equal channel angular pressing, which led to the reduction of average grain size under 1 μm. During subsequent isochronal annealing recovery and recrystallization took place. These processes were monitored by microhardness measurements, light optical microscopy and in-situ transmission electron microscopy. The addition of Zr stabilizes the grain size and increases the recrystallization temperature by 100 °C.

  2. The effect of aluminium on the metallography of a nickel base removable partial denture casting alloy.

    PubMed

    Lewis, A J

    1978-12-01

    Three special nickel-chromium alloys were prepared in which the aluminum levels were adjusted both above and below that of a commercial nickel base dental casting alloy. Tensile and metallographic evaluation of representative samples of the alloys were made and the changes in the properties of the alloys are reported.

  3. Electron irradiation of aluminium-zinc alloys. 2. Radiation-enhanced diffusion in an aluminium-4.5 at% zinc alloy

    NASA Astrophysics Data System (ADS)

    Zhang, Y. G.; Jones, I. P.

    1989-06-01

    A detailed experimental study of electron radiation-enhanced diffusion in aluminium-4.5 at% zinc is presented. The enhancement factor ( D rad/D thermal) was found to be dependent on dose rate, temperature and electron energy, and varied from ~1 at 170°C to ~10 4 at 25°C. At low temperatures recombination dominates whereas at high temperatures linear annealing is the dominant mechanism for annihilation of point defects. The migration energy of vacancies is thus estimated to be 0.58 ±0.06 eV. The results are compared with a theoretical model. The model requires preferential transport of Zn atoms via the interstitial flux to reproduce the experimental results. The simple model D rad = f vD vC v + f iD iC i + … seems to underestimate D rad.

  4. Study of the matrix effect in the secondary ion emission of aluminium-zinc alloys

    NASA Astrophysics Data System (ADS)

    van Craen, M.; Van Espen, P.; Adams, F.

    1981-12-01

    The secondary ion emission of AlZn alloys was studied under Ar + primary ion bombardment at saturation conditions for oxygen adsorption. Relative ionisation coefficients of Al and Zn sputtered from the alloys, were measured as a function of the solute element concentration, which allowed the quantitative evaluation of the matrix effect in SIMS analysis for AlZn alloys.

  5. Small Crack Growth and Fatigue Life Predictions for High-Strength Aluminium Alloys. Part 1; Experimental and Fracture Mechanics Analysis

    NASA Technical Reports Server (NTRS)

    Wu, X. R.; Newman, J. C.; Zhao, W.; Swain, M. H.; Ding, C. F.; Phillips, E. P.

    1998-01-01

    The small crack effect was investigated in two high-strength aluminium alloys: 7075-T6 bare and LC9cs clad alloy. Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks. In the experimental program, fatigue tests, small crack and large crack tests A,ere conducted under constant amplitude and Mini-TWIST spectrum loading conditions. A pronounced small crack effect was observed in both materials, especially for the negative stress ratios. For all loading conditions, most of the fatigue life of the SENT specimens was shown to be crack propagation from initial material defects or from the cladding layer. In the analysis program, three-dimensional finite element and A weight function methods were used to determine stress intensity factors and to develop SIF equations for surface and corner cracks at the notch in the SENT specimens. A plastisity-induced crack-closure model was used to correlate small and large crack data, and to make fatigue life predictions, Predicted crack-growth rates and fatigue lives agreed well with experiments. A total fatigue life prediction method for the aluminum alloys was developed and demonstrated using the crack-closure model.

  6. Formulation of anisotropic Hill criteria for the description of an aluminium alloy behaviour during the channel die compression test

    SciTech Connect

    Gavrus, A.; Francillette, H.

    2007-04-07

    During the last years the study of the plastic deformation modes and the anisotropic mechanical behaviour of aluminium alloys have been the subject of many investigations. This paper deals with a phenomenological identification of an anisotropic Hill constitutive equation of aluminium AU4G samples using a channel die compression device at room temperature. By considering the different possible orientations of the samples in the channel die device, three initial textures, named ND (normal direction Z), LD (longitudinal direction X) and TD (transverse direction Y), were defined with the corresponding stresses {sigma}ND, {sigma}LD and {sigma}TD. To describe the anisotropy of the material, a quadratic Hill criteria is used. An Avrami type equation based on the mixture of the hardening and softening phenomena is used to describe variation of each stress component with the equivalent plastic strain. The identification of the parameters of the law is made using an identification software (OPTPAR) and a good correlation between the experimental stresses and computed ones is obtained. The variation of the Hill parameters with a proposed equivalent strain, describing the deformation history of the material, is analysed. Finally, using the expressions of F, G, H and N, the constitutive equation of the normal anisotropy in the plane XY is obtained.

  7. Formulation of anisotropic Hill criteria for the description of an aluminium alloy behaviour during the channel die compression test

    NASA Astrophysics Data System (ADS)

    Gavrus, A.; Francillette, H.

    2007-04-01

    During the last years the study of the plastic deformation modes and the anisotropic mechanical behaviour of aluminium alloys have been the subject of many investigations. This paper deals with a phenomenological identification of an anisotropic Hill constitutive equation of aluminium AU4G samples using a channel die compression device at room temperature. By considering the different possible orientations of the samples in the channel die device, three initial textures, named ND (normal direction Z), LD (longitudinal direction X) and TD (transverse direction Y), were defined with the corresponding stresses σND, σLD and σTD. To describe the anisotropy of the material, a quadratic Hill criteria is used. An Avrami type equation based on the mixture of the hardening and softening phenomena is used to describe variation of each stress component with the equivalent plastic strain. The identification of the parameters of the law is made using an identification software (OPTPAR) and a good correlation between the experimental stresses and computed ones is obtained. The variation of the Hill parameters with a proposed equivalent strain, describing the deformation history of the material, is analysed. Finally, using the expressions of F, G, H and N, the constitutive equation of the normal anisotropy in the plane XY is obtained.

  8. Application of Minkowski layer for intergranular fractal surfaces of multiphase active microalloyed and alloyed aluminium-silicate ceramics

    NASA Astrophysics Data System (ADS)

    Purenović, J. M.; Randjelović, M. S.; Matović, B. Z.; Purenović, M. M.

    2015-03-01

    Microalloyed and alloyed aluminium-silicate ceramics represents multiphase and multifunctional solid-solid system. The microstructure of aluminium-silicate ceramics matrix is arranged with favorable relationship between crystallinity and amorphousness. Numbered physical processes and interactions take place in very complex intergranular and interphase areas, making new boundaries and regions with fractal nature. Fractal nature of grains contours, macro, mezzo and micro pores and nanostructure phases at grain boundaries make this ceramics an active dielectric material. The synergistic effect of additives, dislocations and impurities leads to dislocations movement at grain boundaries and fragmentation of existing grains in a large number of micrograins with distinct fractal nature. Hence, permanent change of micromorphology occurs in intergranular area. Fractal analysis of intergranular microstructure has included application of Minkowski layer, correlated with fractal dimension. It represents convex layer of grains contour roughness and irregularity, determined in accordance with grain contours fractality. The introduction of fractal microstructure analysis allows better interpretation of many physical and physico-chemical processes, bearing in mind that Minkowski layer defines grains contact probability.

  9. Aging effects of diamond reinforced aluminium alloys submitted to deep space real conditions. Structural, chemical and electrical degradation

    NASA Astrophysics Data System (ADS)

    Korneli, Grigorov; Bouzekova-Penkova, Anna; Datcheva, Maria; Avdeev, George; Grushin, Valerii; Klimov, Stanislav

    2016-07-01

    An aluminium alloy (Al-Cu-Zn-Mg) reinforced with ultra-dispersed diamond powder and tungsten (W), has been prepared in form of 7 cm bars and 4 mm diameter. One part of them stayed 2 years on satellite exposed to outer space, where the Sun activity and the background radiation were monitored. After satellite return both batches has been studied. Structural test, mainly micro-hardness together with detailed X-rays analyses was performed. The satellite makes a tour around the Earth each two hours, the temperature difference being circa 300oC. The micro-hardness being measured with Agilent G200 nano-indentor shows a significant drop of 25%. The XRD patterns are consistent with the previous results, states defects incorporation, and crystalline cells deterioration.

  10. Effects of Welding Processes and Post-Weld Aging Treatment on Fatigue Behavior of AA2219 Aluminium Alloy Joints

    NASA Astrophysics Data System (ADS)

    Malarvizhi, S.; Balasubramanian, V.

    2011-04-01

    AA2219 aluminium alloy square butt joints without filler metal addition were fabricated using gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction stir welding (FSW) processes. The fabricated joints were post-weld aged at 175 °C for 12 h. The effect of three welding processes and post-weld aging (PWA) treatment on the fatigue properties is reported. Transverse tensile properties of the welded joints were evaluated. Microstructure analysis was also carried out using optical and electron microscopes. It was found that the post-weld aged FSW joints showed superior fatigue performance compared to EBW and GTAW joints. This was mainly due to the formation of very fine, dynamically recrystallized grains and uniform distribution of fine precipitates in the weld region.

  11. Effect of friction stir processing on the fatigue properties of a Zr-modified 2014 aluminium alloy

    SciTech Connect

    Cavaliere, P. . E-mail: pasquale.cavaliere@unile.it

    2006-08-15

    The fatigue properties of a Zr-modified 2014 aluminium alloy resulting from friction stir processing (FSP) were analysed in the present study. The sheets were processed parallel to the extrusion direction; the tensile mechanical properties were evaluated at room temperature in the longitudinal direction with respect to the processing one in order to observe the differences from the parent material as a function of the strong grain refinement due to the friction stir process. The fatigue endurance (S-N) curve of the FSP material was obtained by using a resonant electro-mechanical testing machine under constant loading control up to 250 Hz with sine wave loading. The cyclic fatigue tests were conducted in the axial total stress-amplitude control mode with R = {sigma} {sub min}/{sigma} {sub max} = 0.1. The microstructure resulting from the FSW process was studied by employing optical and scanning electron microscopy.

  12. Measurement of surface resistivity/conductivity of anodized aluminium alloy by optical interferometry techniques

    NASA Astrophysics Data System (ADS)

    Habib, K.

    2010-04-01

    Optical interferometry techniques was used for the first time to measure the surface resistivity/conductivity of anodized aluminium samples in aqueous solution without any physical contact. The anodization process (oxidation) of the aluminium samples was carried out in different sulphuric acid solutions (1.0-2.5 % H2SO4), by the technique of electrochemical impedance spectroscopy (EIS), at room temperature. In the mean time, the real-time holographic interferometric was carried out to measure the thickness of anodized (oxide) film of the aluminium samples during the anodization processes. Then, the alternating current (AC) impedance (resistance) of the anodized aluminium samples was determined by the technique of electrochemical impedance spectroscopy (EIS) in different sulphuric acid solutions (1.0-2.5 % H2SO4) at room temperature. In addition, a mathematical model was derived in order to correlate between the AC impedance (resistance) and to the surface (orthogonal) displacement of the samples in solutions. In other words, a proportionality constant (surface resistivity or conductivity=1/ surface resistivity) between the determined AC impedance (by EIS technique) and the orthogonal displacement (by the optical interferometry techniques) was obtained. Consequently the surface resistivity (ρ) and conductivity (σ) of the aluminum samples in solutions were obtained. Also, electrical resistivity values (ρ) from other source were used for comparison sake with the calculated values of this investigation. This study revealed that the measured value of the resistivity for the anodized aluminium samples were 2.8×109, 7×1012, 2.5×1013, and 1.4 ×1012 Ohms-cm in 1.0%,1.5%, 2.0%, and 2.5 % H2SO4 solutions, respectively. In fact, the determined value range of the resistivity is in a good agreement with the one found in literature for the aluminium oxide ,85% Al2O3 (5×1010 Ohms-cm in air at temperature 30C°), 96% Al2O3 (1×1014 Ohms-cm in air at temperature 30C°), and

  13. Regarding to the Variance Analysis of Regression Equation of the Surface Roughness obtained by End Milling process of 7136 Aluminium Alloy

    NASA Astrophysics Data System (ADS)

    POP, A. B.; ȚÎȚU, M. A.

    2016-11-01

    In the metal cutting process, surface quality is intrinsically related to the cutting parameters and to the cutting tool geometry. At the same time, metal cutting processes are closely related to the machining costs. The purpose of this paper is to reduce manufacturing costs and processing time. A study was made, based on the mathematical modelling of the average of the absolute value deviation (Ra) resulting from the end milling process on 7136 aluminium alloy, depending on cutting process parameters. The novel element brought by this paper is the 7136 aluminium alloy type, chosen to conduct the experiments, which is a material developed and patented by Universal Alloy Corporation. This aluminium alloy is used in the aircraft industry to make parts from extruded profiles, and it has not been studied for the proposed research direction. Based on this research, a mathematical model of surface roughness Ra was established according to the cutting parameters studied in a set experimental field. A regression analysis was performed, which identified the quantitative relationships between cutting parameters and the surface roughness. Using the variance analysis ANOVA, the degree of confidence for the achieved results by the regression equation was determined, and the suitability of this equation at every point of the experimental field.

  14. The aluminium-scandium-lithium-magnesium system as a potential source of superplastically formable alloys

    SciTech Connect

    Emigh, R.A.

    1990-07-01

    Alloys from the aluminum-lithium-scandium-magnesium system have been cast and rolled for study. The goal is to evaluate this system for the development of superplastically formable, high strength alloys. Aluminum-scandium-magnesium alloys have shown potential as superplastic alloys. These alloys rely on small Al{sub 3}Sc (ordered L1{sub 2}) precipitates for grain structure stabilization and strengthening. Additional precipitation strengthening is required to raise their strength to levels sufficient for aircraft applications. The addition of lithium provides this additional strengthening through the formation of Al{sub 3}Li({delta}{prime}). To produce the alloys studied in this research, a unique induction melting furnace was constructed that incorporates special features to produce aluminum-lithium alloys with low hydrogen content. The furnace also features a water cooled, copper casting mold to achieve a moderately rapid solidification rate. This is because the amount of scandium used (0.5 wt %) is in excess of the solubility limit and Al{sub 3}Sc cannot be re-solutionized to any extent. It is therefore desired to super-saturate the matrix with as much scandium as possible for later precipitation. Two high lithium alloys were produced, ALS2 (nominal composition Al-2.2Li-O.5 Sc) and AlS4 (nominal composition Al-2.0Li-2.2Mg-0.5Sc) that were strengthened with {delta}{prime} (Al{sub 3}Li). These alloys exhibited strength and ductility superior to those of aluminum-lithium-(magnesium)-zirconium alloys. This is because the scandium containing alloys have developed a finer grain structure and the Al{sub 3}Sc precipitates contribute to the alloys strength. 41 refs., 29 figs.

  15. Enhancing elevated temperature strength of copper containing aluminium alloys by forming L12 Al3Zr precipitates and nucleating θ″ precipitates on them.

    PubMed

    Kumar Makineni, Surendra; Sugathan, Sandeep; Meher, Subhashish; Banerjee, Rajarshi; Bhattacharya, Saswata; Kumar, Subodh; Chattopadhyay, Kamanio

    2017-09-11

    Strengthening by precipitation of second phase is the guiding principle for the development of a host of high strength structural alloys, in particular, aluminium alloys for transportation sector. Higher efficiency and lower emission demands use of alloys at higher operating temperatures (200 °C-250 °C) and stresses, especially in applications for engine parts. Unfortunately, most of the precipitation hardened aluminium alloys that are currently available can withstand maximum temperatures ranging from 150-200 °C. This limit is set by the onset of the rapid coarsening of the precipitates and consequent loss of mechanical properties. In this communication, we present a new approach in designing an Al-based alloy through solid state precipitation route that provides a synergistic coupling of two different types of precipitates that has enabled us to develop coarsening resistant high-temperature alloys that are stable in the temperature range of 250-300 °C with strength in excess of 260 MPa at 250 °C.

  16. Three-dimensional characterization of fatigue-relevant intermetallic particles in high-strength aluminium alloys using synchrotron X-ray nanotomography

    NASA Astrophysics Data System (ADS)

    Nizery, E.; Proudhon, H.; Buffiere, J.-Y.; Cloetens, P.; Morgeneyer, T. F.; Forest, S.

    2015-09-01

    Second-phase particles and small porosities are known to favour fatigue crack initiation in high-strength aluminium alloys 2050-T8 and 7050-T7451. Using high-resolution X-ray tomography (320 nm voxel size), with Paganin reconstruction algorithms, the probability that large clusters of particles contain porosities could be measured for the first time in 3D, as well as precise 3D size distributions. Additional holotomography imaging provided improved spatial resolution (50 nm voxel size), allowing to estimate the probability of finding cracked particles in the as-received material state. The extremely precise 3D shape (including cracks) as well as local chemistry of the particles has been determined. This experiment enabled unprecedented 3D identification of detrimental stress risers relevant for fatigue in as-received aluminium alloys.

  17. Comparative Investigation on Modal analysis of LM25 Aluminium alloy with other Aluminim alloys using Finite element analysis software

    NASA Astrophysics Data System (ADS)

    Arunkumar, S.; Baskaralal, V. P. M.; Muthuraman, V.

    2017-03-01

    The rudimentary steps of the modal analysis and simulation are carried out. The modal analysis is carried out on the different Aluminum Alloys cantilever beam. The cantilever beam is designed in the graphical environment of the ANSYS. The cantilever beam was fine-tuned on one end with all degree of liberation on this end were taken, beam cannot move and rotate. Mode shapes and natural frequencies are premeditated in platforms ANSYS with arithmetical formulation of the direct solver including the block Lanczos method. Aluminum alloys are widely utilized in much application due to their estimable weight to vigor property. Many examination works have been distributed out to make developments the mechanical properties of aluminum alloys. The composition of alloying elements plays a consequential role in deciding the properties of an alloy. In this study a numerical analysis implement i.e., finite element analysis (FEA) is utilized. The work obtainable in this paper is aimed at the study of effect of modal analysis of different aluminum alloys. The modeling and analysis is carried out utilizing ANSYS FEA software. A modal analysis is carried out to understand the modes of frequency demeanor of the material considered. The modal analysis play a vital role in the design of components subjected to high vibration.

  18. Effect of post annealing temperatures on microstructures and mechanical properties of cryorolled 5052 aluminium sheet alloy

    NASA Astrophysics Data System (ADS)

    Anas, N. M.; Umar, Z. A. A.; Zuhailawati, H.; Anasyida, A. S.

    2017-07-01

    The effect of post annealing temperature of cryorolled 5052 Al alloy after cryorolling process at 30% thickness reduction was investigated, focusing on the evolution of microstructures and mechanical properties. The evolution of microstructure was investigated using optical microscopy (OM). The mechanical behaviour of the samples have been evaluated through Vickers hardness and tensile test performed at room temperature. The results showed that the post annealing on cryorolled 5052 Al alloy have enhanced the ductility with sacrificing the hardness and strength. The lattice strain of post annealed 5052 Al alloy decreased with increasing of annealing temperatures. The evolution of microstructure of the post annealed 5052 Al alloy showed equiaxed grains at 200°C and grain coarsening as post annealing temperature increases to 350°C. The result of crystallite size confirmed the grain size increased as the post annealing temperature rises.

  19. The Effect of Chemical Composition and Structure on the Corrosion Resistance of Plated Aluminium Alloy Strips

    NASA Astrophysics Data System (ADS)

    Klyszewski, Andrzej; Zelechowski, Janusz; Opyrchal, Mieczyslaw; Nowak, Marek; Frontczak, Andrzej; Rutecki, Pawel

    Thin 3003 alloy strips plated with 4343 alloy were subjected to microstructure examinations, X-ray phase analysis, corrosion testing, and measurement of basic mechanical properties. In a similar manner, the properties of heat exchangers made from the plated strip were characterised, watching the long-term consequences of their use in vehicles. The results of investigations were applied in the manufacturing technology of thin plated strips for heat exchangers used by the automotive industry.

  20. The New Heat Treatment Technology of A356 Aluminium Alloy Prepared by Ptc

    NASA Astrophysics Data System (ADS)

    Zhang, Lianyong; Jiang, Yanhua; Ma, Zhuang; Wang, Wenkui

    Phase Transition Cooling (PTC), using the absorbed latent heat during the melting of phase transition cooling medium to cool and solidify alloys in the process of casting, is a new casting technology. Specimens of A356 casting aluminum alloy were prepared by this method in the paper. The new heat treatment process (cast and then aging directly without solid solution) of A356 alloy was performed. For comparison, the conventional T6 heat treatment (solution and then aging treatment) was performed too. The mechanical properties of A356 alloy with different heat treatments were measured by tensile strength testing methods and microstructures of the alloy with different heat treatment process were investigated by optical microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-rays diffraction (XRD) and transmission electron microscopy (TEM) too. The results show that ultimate tensile strength (UTS) of A356 alloy with the new heat treatment process is much higher than that with conventional heat treatment while the elongations with the two heat treatment processes are very close. This is due to the grain refinement obtained after PTC processing.

  1. Grain Boundary Sliding in Ultra-fine Grained 5083 Aluminium Alloy

    NASA Astrophysics Data System (ADS)

    Sung, Ming-Je

    Quantitative measurement and analysis of grain boundary sliding in Ultra-fine grained 5083 Aluminium by AFM was conducted at 623K. The grain size of as received cryomilled Ultra-fine Grained Aluminium was characterized by AFM and TEM, and the average was founded to be about 300nm. Ion beam polishing / etching technology was used to reveal grain boundaries for AFM characterization. The vertical offset of grain boundary sliding was measured by comparing pre-defoemation and post-deformation AFM images. By analyzing these measurements, the contribution of grain boundary sliding to the total strain was estimated as 22% - 52% at a strain rate of 10 -4 /sec -5x10-2/sec. It was demonstrated that the relatively low value of the contribution of grain boundary sliding to the total strain is most likely the result of testing under experimental condition that favor the dominance of region I ( low stress) of the sigmoidal behavior characterizing high strain rate superplasticity, which was previously reported.

  2. Synergism between cerium nitrate and sodium dodecylbenzenesulfonate on corrosion of AA5052 aluminium alloy in 3 wt.% NaCl solution

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Wang, Dapeng; Gao, Lixin; Zhang, Daquan

    2016-12-01

    The synergistic inhibition effect of rare earth cerium nitrate and sodium dodecylbenzenesulfonate (DBS) on corrosion of AA5052 aluminium alloy in 3 wt.% NaCl solution was investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). The results show that the single cerium nitrate or DBS has a limited inhibition effect against corrosion of AA5052 alloy. The combination cerium ions with DBS produced strong synergistic effect on corrosion inhibition for AA5052 alloy and rendered a negaitve shift of the corrosion potential. The formation of the complex of Al(DBS)3 and Ce(DBS)3 stabilized the passive film of Al2O3 and CeO2, retarding both the cathodic and anodic processes of AA5052 alloy corrosion reaction significantly.

  3. Effect of thermal exposure on mechanical properties hypo eutectic aerospace grade aluminium-silicon alloy

    NASA Astrophysics Data System (ADS)

    Nagesh Kumar, R.; Ram Prabhu, T.; Siddaraju, C.

    2016-09-01

    The effect of thermal exposure on the mechanical properties of a C355.0 aerospace grade aluminum-silicon alloy (5% Si - 1.2% Cu - 0.5% Mg) was investigated in the present study. The alloy specimens were subjected to T6 (solution treatment and artificial ageing treatment) temper treatment to enhance the strength properties through precipitation hardening. The T6 temper treatment involved solution heat treatment at 520oC for 6h, followed by water quenching and ageing at 150oC. After the heat treatment, the specimens were exposed to various temperatures (50oC, 100oC, 150oC, 200oC and 250oC) for 5 and 10 h to study the structural applications of this alloy to the various Mach number military aircrafts. After the thermal exposure, specimens were tested for tensile, hardness and impact properties (Charpy). The microstructure of the thermal exposed specimens was examined in the optical microscopes and correlated with the mechanical properties results. In summary, an increase of exposure time has a different effect on the tensile and hardness properties of the alloy. For the exposure time 5h, the tensile and hardness properties increase upto 100oC and later decrease with an increase of temperature. In contrast, the tensile and hardness properties linearly decrease with an increase of temperature. Several factors such as matrix grain growth, diffusion rate, Si particles size and distribution, precipitate stability play a key role on deciding the tensile properties of the alloy. Comparing the relative effects of temperature and time, the temperature effects dominate more in deteriorating tensile properties of the alloy. There are no effects of exposure temperature and/or time on the impact properties of the alloy.

  4. Computation material science of structural-phase transformation in casting aluminium alloys

    NASA Astrophysics Data System (ADS)

    Golod, V. M.; Dobosh, L. Yu

    2017-04-01

    Successive stages of computer simulation the formation of the casting microstructure under non-equilibrium conditions of crystallization of multicomponent aluminum alloys are presented. On the basis of computer thermodynamics and heat transfer during solidification of macroscale shaped castings are specified the boundary conditions of local heat exchange at mesoscale modeling of non-equilibrium formation the solid phase and of the component redistribution between phases during coalescence of secondary dendrite branches. Computer analysis of structural - phase transitions based on the principle of additive physico-chemical effect of the alloy components in the process of diffusional - capillary morphological evolution of the dendrite structure and the o of local dendrite heterogeneity which stochastic nature and extent are revealed under metallographic study and modeling by the Monte Carlo method. The integrated computational materials science tools at researches of alloys are focused and implemented on analysis the multiple-factor system of casting processes and prediction of casting microstructure.

  5. Effects of laser shock processing on the fatigue life of 2024-T62 aluminium alloy

    SciTech Connect

    Zhang Hong; Lu Boliang; Zhang Shuren; Tang Yaxin; Yu Chengye

    1996-12-31

    Laser shock processing (LSP) is a new technology for strengthening the materials. The feasibility of using a high energy, pulsed laser beam to shock-harden the localized stress concentration zone, i.e., small holes in 2024-T62 aluminum alloy was investigated in this paper. Confining plasma technique was used in the study. In order to generate the pressure which is required to exceed the dynamic yield strength of 2024-T62 aluminum alloy, laser parameters were optimized. The fatigue life of specimens was studied before and after laser shocking. The fatigue tests showed that the fatigue life of 2024-T62 aluminum alloy treated by LSP had been improved significantly. With 95% confidence, the median fatigue life of shocked specimens was 1.9 to 2.5 times than that of unshocked ones. It is expected that LSP will be used as a good treatment for improving the fatigue life of aviation structures.

  6. Laser-induced electrochemical de- and repassivation investigations on plasma-oxidized aluminium alloys

    NASA Astrophysics Data System (ADS)

    Nagy, Tristan O.; Pacher, Ulrich; Giesriegl, Ariane; Soyka, Lukas; Trettenhahn, Günter; Kautek, Wolfgang

    2014-05-01

    In situ laser depassivation of plasma electrolytically oxididized (PEO) coatings on aluminium was investigated with nanosecond pulses. Ultraviolet radiation of 266 nm was chosen in order to achieve a high absorption in the dielectric coating. The additive accumulation of laser-induced material defects (incubation) affected the depassivation processes. Incubation occurred only at the edges of the ablation craters irradiated by the outer region of the Gaussian beam profile, where the local fluence is below the ablation threshold. The ablation rate in the spot center did not exhibit an incubation effect. Repassivation was interpreted by a linear combination of a high-field and a point defect growth model. At low overpotentials, field gradients affect the process driving the oxide growth at the buried interface. At high fields, corrosion reactions dominate at the oxide/solution interface.

  7. Anisotropy of elastic properties in various aluminium-lithium sheet alloys

    SciTech Connect

    Zeng, X.H.; Ericsson, T.

    1996-05-01

    Anisotropic elastic properties of recrystallized and unrecrystallized Al-Li sheets have been experimentally studied and compared with theoretically predicted results. A conventional AA2024 alloy in the annealed condition as a reference material has also been investigated. A concept of lithium equivalent has been proposed in order to calculate single crystal elastic constants C{sub 11}, C{sub 12} and C{sub 44} for commercial Al sheet alloys. Subsequently, these calculated single crystal elastic constants were applied to predict the Young`s modulus, using Bunge`s method with quantitative texture data which were determined by X-ray and neutron diffraction techniques. To calculate the shear modulus the Bunge`s method was extended. It is shown that elastic properties of the alloys can be essentially predicted on the basis of Bunge`s method with calculated single crystals C{sub ij}. The measurement results of the Young`s modulus and shear modulus of polycrystalline Al-Li alloys were carried out using a dynamic resonance method. They were found to be in fair agreement with calculated curves using the neutron texture data with the calculated single crystal elastic constants C{sub ij}. The results showed that elastic properties depend strongly on testing direction due to the crystallographic texture and grain shape. The texture gradients also strongly affected the elastic properties of Al-Li alloys, but only slightly affected those of the conventional 2024 Al alloy. A slight stretch reduces the modulus of Al-Li by a small amount.

  8. Behaviour and modelling of aluminium alloy AA6060 subjected to a wide range of strain rates and temperatures

    NASA Astrophysics Data System (ADS)

    Vilamosa, Vincent; Børvik, Tore; Sture Hopperstad, Odd; Holm Clausen, Arild

    2015-09-01

    The thermo-mechanical behaviour in tension of an as-cast and homogenized AA6060 alloy was investigated at a wide range of strains (the entire deformation process up to fracture), strain rates (0.01-750 s-1) and temperatures (20-350 ∘C). The tests at strain rates up to 1 s-1 were performed in a universal testing machine, while a split-Hopkinson tension bar (SHTB) system was used for strain rates from 350 to 750 s-1. The samples were heated with an induction-based heating system. A typical feature of aluminium alloys at high temperatures is that necking occurs at a rather early stage of the deformation process. In order to determine the true stress-strain curve also after the onset of necking, all tests were instrumented with a digital camera. The experimental tests reveal that the AA6060 material has negligible strain-rate sensitivity (SRS) for temperatures lower than 200 ∘C, while both yielding and work hardening exhibit a strong positive SRS at higher temperatures. The coupled strain-rate and temperature sensitivity is challenging to capture with most existing constitutive models. The paper presents an outline of a new semi-physical model that expresses the flow stress in terms of plastic strain, plastic strain rate and temperature. The parameters of the model were determined from the tests, and the stress-strain curves from the tests were compared with the predictions of the model. Good agreement was obtained over the entire strain rate and temperature range.

  9. Aluminium/lithium alloy-CFRP hybrid laminate: Fabrication and properties

    SciTech Connect

    Freischmidt, G.; Coutts, R.S.P.; Janardhana, M.N.

    1993-12-31

    Hybrid composite laminates of aluminum and aluminum/lithium alloy sheeting with unidirectional carbon fiber/epoxy plies have been fabricated to produce sheet materials of high strength, low density and reduced fatigue crack growth rate. In an arrangement of one layer of unidirectional carbon fiber reinforced plastic (CFRP) and 2 sheets of 2090-T3 aluminum alloy was used to give a material with a density of 2.20g/cm{sup 3}. Tensile test results gave an ultimate strength of 803MPa, a modulus of 75.7GPa and a 2% offset yield strength of 497MPa. Preliminary fatigue crack growth rate determinations on single edge notch (SEN) specimens show a marked reduction compared to monolithic 2090-T3. Other hybrid laminates using 2024-T3 alloy have also been made and tested. These laminates show reduced tensile properties, however, they appear to have lower fatigue crack growth rates than when using 2090T3 in hybrid form. The fabrication of hybrid laminates included the use of unsupported adhesive film to bond the precured unidirectional carbon fiber composite plies to the aluminum sheeting. This has left a distinct interphase region between the alloy and CFRP which is thought to improve properties through an effective load transfer.

  10. Influence of post-superplastic forming practices on the tensile properties of aluminium-lithium alloys

    SciTech Connect

    Hales, S.J. ); Lippard, H.E. . Dept. of Materials Science)

    1994-06-01

    The effect of thermal processing following superplastic forming on the tensile properties of aluminum-lithium alloys is addressed. The starting materials consisted of alloys 8090, 2090, and X2095 (a Weldalite[trademark] 049 variant) in the form of commercial-grade superplastic sheet. Experience dictates that post-forming practices aimed at a slightly underaged T6 temper produce balanced engineering properties in these alloys. The objective of this study was to assess the potential to use a T5-type temper by eliminating the solution heat treatment and/or cold water quenching steps characteristic of T6 processing. The experimental procedures adopted ensured that the tensile properties compiled were representative of the bulk material Initially, the strengthening behavior of each alloy as a function of temper selection was established. Subsequently, aging practices that resulted in peak strength and balanced properties were identified for the baseline T6 temper and two T5 tempers. The implications for replacing a T6 temper with a T5-type temper, including rapid and slow cooling following forming, are discussed on the basis of the results.

  11. Estimating multivariate response surface model with data outliers, case study in enhancing surface layer properties of an aircraft aluminium alloy

    NASA Astrophysics Data System (ADS)

    Widodo, Edy; Kariyam

    2017-03-01

    To determine the input variable settings that create the optimal compromise in response variable used Response Surface Methodology (RSM). There are three primary steps in the RSM problem, namely data collection, modelling, and optimization. In this study focused on the establishment of response surface models, using the assumption that the data produced is correct. Usually the response surface model parameters are estimated by OLS. However, this method is highly sensitive to outliers. Outliers can generate substantial residual and often affect the estimator models. Estimator models produced can be biased and could lead to errors in the determination of the optimal point of fact, that the main purpose of RSM is not reached. Meanwhile, in real life, the collected data often contain some response variable and a set of independent variables. Treat each response separately and apply a single response procedures can result in the wrong interpretation. So we need a development model for the multi-response case. Therefore, it takes a multivariate model of the response surface that is resistant to outliers. As an alternative, in this study discussed on M-estimation as a parameter estimator in multivariate response surface models containing outliers. As an illustration presented a case study on the experimental results to the enhancement of the surface layer of aluminium alloy air by shot peening.

  12. Experimental investigation on the effects of cooling system on surface quality in high speed milling of an aluminium alloy

    NASA Astrophysics Data System (ADS)

    Chirita, B.; Tampu, N. C.; Brabie, G.; Radu, M. C.

    2016-08-01

    Surface quality is often an important feature of industrial products, not only from the impact it has on the aesthetic aspect but also for the functional role of the parts. High quality surface increases corrosion resistance, assures a longer life cycle for the product and lowers the wear. For a machined part, surface quality is influenced by a series of factors such as the material of the part, the process type, tool geometry, cutting parameters or the cooling system. The choice of the cooling system is especially important, taking into account that the proper conditions will not only assure a superior surface quality, but will also lower the costs and reduce the environmental impact and health risks. The present study aims to investigate the performance of the cooling system and the effect of the cutting parameters on the characteristics of the surfaces resulted from high speed face milling of some parts made of Al 7050-T7451 aluminium alloy. Dry cutting conditions and minimum quantity lubrication (MQL) where used. The results were analysed using analysis of variance (ANOVA).

  13. Impact resistance and hardness modelling of Aluminium alloy welds using square-headed friction-stir welding tool

    NASA Astrophysics Data System (ADS)

    Sudhakar, U.; Srinivas, J., Dr.

    2016-02-01

    This paper proposes modelling and optimization issues relating to friction-stir welding process of aluminium alloys. A specially prepared SS tool of square headed pin profile with cylindrical shoulder is used with a vertical milling machine. Effects of process variables including tool rotation and tool velocity on the weld performance are studied in terms of impact strength and hardness. Three different rotational motions and three welding speeds (feeds) of tool are considered at constant axial load (depth of cut) condition and altogether nine experiments are conducted on a vertical milling machine with specially prepared fixture. Each weld sample is then tested for its impact strength (IS) and hardness independently. A model is developed to correlate the relations between the hardness/impact strength with tool rotation and weld speed using neural networks. The optimized process conditions are predicted to improvise the impact strength and hardness of the weld. Further, the morphology of the weld is studied using SEM to know the material flow characteristics.

  14. Fractal analysis of surface micro-topography for a rolled anisotropic thick sheet of aluminium alloy AA2024-T351

    NASA Astrophysics Data System (ADS)

    Pirva, E.; Tudor, A.; Gavrus, A.

    2016-08-01

    Fractal geometry has gained attention in recent years and represents a problem of high interest for the characterization of surface topography. In this study it was analyzed the surface micro-topography for a rolled thick sheet anisotropic metallic material of type 2000 series aluminium alloy (AA2024-T351). In order to analyze and to characterize the corresponding anisotropic surfaces, profile of particular samples were recorded with a specialized apparatus Mitutoyo SJ-301 (Japan). The random nature of the roughness height is described through statistical analysis. The irregularity of the surface profile has been measured using a lot of conventional surface roughness parameters such as: arithmetic average, mean square root, maximum height of the profile, etc. Fractal analysis provides a useful way to characterize the observed spatial complexity of surface micro-topography. For this study it was used the structural function method to calculate two specific fractal parameters: D (fractal dimension) and L (topothesy). The fractal dimension of all samples it's been be calculated by plotting curves on log-log axes.

  15. Collected studies on interfaces and interphases as related to the behaviour of fibre-reinforced aluminium alloy composites

    PubMed

    Scott; Chen

    1999-11-01

    This paper is an essentially practical treatment of interphases and interfaces and of their influence on the properties of a number of metal matrix composites (MMCs). The illustrations are drawn from the authors' experiences and have been chosen to underline the importance of detailed microstructural analysis for elucidating the fabrication behaviour and the mechanical performance of this group of materials. The work involves a series of MMCs based upon different combinations of aluminium alloy and ceramic/carbon fibre (both continuous and short) and made using the method of low-pressure liquid metal infiltration (LMI). Detailed analyses of the composite microstructures are given, with particular attention being paid to the interface regions. The data are used to categorize an interface according to the type of bond, that is a mechanical bond resulting from thermal mismatch between the fibre and metal matrix, or a chemical bond, with or without second phase, caused by chemical reaction. The information is then employed to account for aspects of composite fabrication, such as the cast microstructure produced by the LMI method and the effect of heat treatment, and to elucidate composite properties such as stiffness, yield stress and failure strength.

  16. Structure-property relationships in Al{sub 2}O{sub 3} short fiber and SiC particle reinforced aluminium alloys

    SciTech Connect

    Harris, S.J.; Cai, H.W.; Weatherburn, P.C.

    1993-12-31

    A study has been made of how Saffil {delta}-Al{sub 2}O{sub 3} fibres and {alpha}-SiC particles influence the microstructure and properties of two types of heat-treatable aluminium alloys, i.e. aluminum-copper and aluminium-copper-magnesium (2124, 2618A) alloys. Natural aging (T4) of the binary Al-Cu alloys was virtually prevented by the reinforcements, while in the case of the AlCu-Mg alloys, hardening did take place at a similar rate. Magnesium additions, it is believed, maintained the concentration of quenched in vacancies thus permitting GPB zone formation and in consequence increases in proof stress and tensile strength values. Artificial aging of these reinforcement composites helped to promote {theta}{prime}(CuAl{sub 2}) precipitation at lower temperatures. These precipitates nucleated on the increased dislocation density which arose from differential thermal effects between reinforcement and matrix. The limit of proportionality, tensile strength and ductility of short fiber reinforced composites are not as well developed as with the particulate systems because of enhanced tensile residual stresses in the matrix, fiber cracking and strong fiber-matrix bonding.

  17. The effect of aluminium on the creep behavior of titanium aluminide alloys

    SciTech Connect

    Nandy, T.K.; Mishra, R.S.; Gogia, A.K.; Banerjee, D.

    1995-03-15

    Small increases in the Al content of Ti{sub 3}Al-Nb alloys are known to improve creep resistance at the expense of the room temperature ductility. Though considerable work has been done on the creep behavior of titanium aluminide alloys, a systematic investigation involving the role of Al on the creep of aluminides is lacking. In the present study the authors have therefore carried out a complete investigation on stress and temperature effects on two alloys with differing Al contents, Ti-24Al-15Nb and Ti-26Al-15Nb (nominal composition in at%) in order to understand the effect of Al in terms of power law creep behavior. The following conclusions are made: (1) A strong Al effect on the creep resistance of O phase alloys in the Ti-Al-Nb systems has been confirmed, through a study of stress and temperature effects on the creep behavior of the Ti-24Al-15Nb and the Ti-26Al-15Nb compositions. (2) It has been shown, however, that the small differences in Al do not affect either the activation energies for creep ({approximately}370 kJ/mole) or the creep mechanism (climb controlled creep with a stress exponent of 4). The activation energies and stress exponents are similar to that observed in single phase O alloys. (3) It is suggested that Al influences creep strength through an intrinsic effect on the pre-exponential term AD{sub o} in the power law creep equation. It is possible that this effect is related to a higher ordering energy of the O phase with increasing Al content.

  18. Electron Transport Properties of Aluminium Substituted CuTi Amorphous Alloys

    NASA Astrophysics Data System (ADS)

    Bhatnagar, A. K.; Fritsch, G.; Naugle, D. G.; Haberkern, R.; Kandlbinder, M.; Lindqvist, P.

    Room temperature electrical resistivity (ρ), temperature coefficient of resistivity (α) and Hall coefficient (RH) of (Cu1-yTiy)1-xAlx amorphous alloys, where y=0.36, 0.50 and 0.64 and x=0, 0.05 and 0.10 are presented. The low temperature dependence of resistivity and magnetoresistivity of a-(Cu0.36Ti0.64)1-xAlx are also presented and discussed qualitatively in terms of quantum corrections. It is found that the addition of Al in a-Cu0.36Ti0.64 alloy decreases the spin-orbit scattering time τso.

  19. Electron transport properties of aluminium substituted CuTi amorphous alloys

    SciTech Connect

    Bhatnagar, A.K.; Fritsch, G.; Haberkern, R.; Kandlbinder, M.; Lindqvist, P.; Naugle, D.G.

    1997-01-30

    Room temperature electrical resistivity ({rho}) temperature coefficient of resistivity ({alpha}) and Hall coefficient (R{sub H}) of (Cu{sub 1{minus}y}Ti{sub y}){sub 1{minus}x}Al{sub x} amorphous alloys, where y = 0.36, 0.50 and 0.64 and x = 0, 0.05 and 0.10 are presented. The low temperature dependence of resistivity and magnetoresistivity of a-(Cu{sub 0.36}Ti{sub 0.64}){sub 1{minus}x}Al{sub x} are also presented and discussed qualitatively in terms of quantum corrections. It is found that the addition of Al in a Cu{sub 0.36}Ti{sub 0.64} alloy decreases the spin-orbit scattering time {tau}{sub so}.

  20. Emission of nanoparticles during friction stir welding (FSW) of aluminium alloys.

    PubMed

    Gomes, J F; Miranda, R M; Santos, T J; Carvalho, P A

    2014-01-01

    Friction stir welding (FSW) is now well established as a welding process capable of joining some different types of metallic materials, as it was (1) found to be a reliable and economical way of producing high quality welds, and (2) considered a "clean" welding process that does not involve fusion of metal, as is the case with other traditional welding processes. The aim of this study was to determine whether the emission of particles during FSW in the nanorange of the most commonly used aluminum (Al) alloys, AA 5083 and AA 6082, originated from the Al alloy itself due to friction of the welding tool against the item that was being welded. Another goal was to measure Al alloys in the alveolar deposited surface area during FSW. Nanoparticles dimensions were predominantly in the 40- and 70-nm range. This study demonstrated that microparticles were also emitted during FSW but due to tool wear. However, the biological relevance and toxic manifestations of these microparticles remain to be determined.

  1. A predictive mechanism for dynamic strain ageing in aluminium-magnesium alloys.

    PubMed

    Curtin, William A; Olmsted, David L; Hector, Louis G

    2006-11-01

    Dynamic strain ageing (DSA) is the phenomenon in which solute atoms diffuse around dislocations and retard dislocation motion, leading to negative strain-rate sensitivity (nSRS) and thus to material instabilities during processing, an important issue in commercial metal alloys. Here, we show the mechanism of DSA and nSRS on experimental strain-rate, temperature and stress scales for Al-Mg to be single-atomic-hop motion of solutes from the compression to the tension side of a dislocation core. We derive an analytic expression for the strengthening versus strain rate and temperature that justifies widely used phenomenological forms, provides specific dependences of the parameters on material properties and is supported by atomistic kinetic Monte Carlo simulations. Using literature material properties, the predicted strengthening quantitatively agrees with the experimentally derived behaviour of Al-2.5% Mg at 300 K, and qualitatively agrees with the strain rate and temperature ranges of DSA and nSRS in Al-Mg alloys. The analyses herein show a clear path for multiscale design, from quantum to continuum mechanics, of solute strengthening in face-centred-cubic metal alloys.

  2. Finite Element Modelling of the Sawing of DC Cast AA2024 Aluminium Alloy Slabs

    SciTech Connect

    Drezet, J.-M.; Ludwig, O.; Heinrich, B.

    2007-04-07

    In the semi-continuous casting of large cross-section rolling sheet ingots of high-strength aluminum alloys (2xxx and 7xxx series), the control of the residual (internal) stresses generated by the non-uniform cooling becomes a necessity. These stresses must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts may be ejected thus injuring people or damaging equipment. These high added-value ingots need to be produced in secure conditions. Moreover, a better control of the sawing procedure could allow the suppression of the thermal treatment and therefore save time and energy. By studying the stress build-up during casting and the stress relief during sawing, key parameters for the control and optimization of the processing steps, can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy is modeled with ABAQUS 6.5 with special attention to the thermo-mechanical properties of the alloy. The sawing operation is then simulated by removing mesh elements so as to reproduce the progression of the saw in the ingot. Preliminary results showing the stress relief during sawing accompanied by the risk of saw blocking due to compression or initiating a crack ahead of the saw, are analyzed with an approach based on the rate of strain energy release.

  3. The fatigue life prediction of aluminium alloy using genetic algorithm and neural network

    NASA Astrophysics Data System (ADS)

    Susmikanti, Mike

    2013-09-01

    The behavior of the fatigue life of the industrial materials is very important. In many cases, the material with experiencing fatigue life cannot be avoided, however, there are many ways to control their behavior. Many investigations of the fatigue life phenomena of alloys have been done, but it is high cost and times consuming computation. This paper report the modeling and simulation approaches to predict the fatigue life behavior of Aluminum Alloys and resolves some problems of computation. First, the simulation using genetic algorithm was utilized to optimize the load to obtain the stress values. These results can be used to provide N-cycle fatigue life of the material. Furthermore, the experimental data was applied as input data in the neural network learning, while the samples data were applied for testing of the training data. Finally, the multilayer perceptron algorithm is applied to predict whether the given data sets in accordance with the fatigue life of the alloy. To achieve rapid convergence, the Levenberg-Marquardt algorithm was also employed. The simulations results shows that the fatigue behaviors of aluminum under pressure can be predicted. In addition, implementation of neural networks successfully identified a model for material fatigue life.

  4. A predictive mechanism for dynamic strain ageing in aluminium-magnesium alloys

    NASA Astrophysics Data System (ADS)

    Curtin, William A.; Olmsted, David L.; Hector, Louis G.

    2006-11-01

    Dynamic strain ageing (DSA) is the phenomenon in which solute atoms diffuse around dislocations and retard dislocation motion, leading to negative strain-rate sensitivity (nSRS) and thus to material instabilities during processing, an important issue in commercial metal alloys. Here, we show the mechanism of DSA and nSRS on experimental strain-rate, temperature and stress scales for Al-Mg to be single-atomic-hop motion of solutes from the compression to the tension side of a dislocation core. We derive an analytic expression for the strengthening versus strain rate and temperature that justifies widely used phenomenological forms, provides specific dependences of the parameters on material properties and is supported by atomistic kinetic Monte Carlo simulations. Using literature material properties, the predicted strengthening quantitatively agrees with the experimentally derived behaviour of Al-2.5% Mg at 300K, and qualitatively agrees with the strain rate and temperature ranges of DSA and nSRS in Al-Mg alloys. The analyses herein show a clear path for multiscale design, from quantum to continuum mechanics, of solute strengthening in face-centred-cubic metal alloys.

  5. Microstructural and mechanical investigation of aluminium alloy (Al 1050) melted by microwave hybrid heating

    NASA Astrophysics Data System (ADS)

    Shashank Lingappa, M.; Srinath, M. S.; Amarendra, H. J.

    2017-07-01

    Microwave processing of metals is an emerging area. Melting of bulk metallic materials through microwave irradiation is still immature. In view of this, the present paper discusses the melting of bulk Al 1050 metallic material through microwave irradiation. The melting process is carried out successfully in a domestic microwave oven with 900 W power at 2450 MHz frequency. Metallurgical and mechanical characterization of the processed and as-received material is carried out. Aluminium phase is found to be dominant in processed material when tested through x-ray diffraction (XRD). Microstructure study of as-cast metal through scanning electron microscopy (SEM) reveals the formation of uniform hexagonal grain structure free from pores and cavities. The average tensile strength of the cast material is found to be around 21% higher, when compared to as-received material. Vickers’ microhardness of the as-cast metal is measured and is 10% higher than that of the as-received metal. Radiography on as-cast metal shows no significant defects. Al 1050 material melted through microwave irradiation has exhibited superior properties than the as-received Al 1050.

  6. The effect of pre-straining and pre-ageing on a novel thermomechanical treatment for improving the mechanical properties of AA2139 aerospace aluminium alloys

    NASA Astrophysics Data System (ADS)

    Bakare, F.; Alsubhi, Y.; Ragkousis, A.; Ebomwonyi, O.; Damisa, J.; Okunzuwa, S.

    2017-07-01

    The novel thermomechanical treatment employed by Wang Z et al (2014 Mater. Sci. Eng. A 607 313-7) in enhancing the mechanical and microstructure properties of 6000 series aluminium alloys has been replicated for AA2139 aerospace aluminium alloys. The novel route which involves under-ageing, cold-rolling reductions and re-ageing at a fixed temperature has been carried out focusing on the effect of pre-straining and pre-ageing on the alloy properties. The influence of varying cold-rolling reductions and pre-ageing has been examined by tensile testing, hardness testing, differential scanning calorimetry, thermoelectric power measurements and scanning electron microscope (SEM). Further analyses were conducted with DSC and TEP measurements to check for precipitation sequence and solute retention respectively. On comparing the hardness and strength of the non pre-aged to the pre-aged samples, there is a remarkable increase in the hardness and strength of the aerospace alloy showing the huge influence of both pre-ageing and pre-straining stage of the novel thermomechanical treatment as observed in the 6000 series alloy, albeit at a higher rate. The treatments that exhibited the most promising mechanical properties (hardness, yield and ultimate tensile strength, elongation to failure) were found to be at a pre-ageing temperature of 175 °C for 1.5 h, 40% cold-rolling and re-ageing at 150 °C. The material was found to have yield strength of 590 MPa and 8.1% uniform elongation, which is well above the 5% acceptable value for structural applications and with strength levels adaptable for aerospace industries. The presence of higher volume fraction of well dispersed precipitates observed in the SEM further shows that intermediate cold-rolling reductions combines well with pre-ageing to give the best mechanical properties in this alloy.

  7. Studies and research on the crack testing for brazed aluminium alloys specimens

    NASA Astrophysics Data System (ADS)

    Dimitescu, A.; Babiş, C.; Niţoi, D. F.; Radu, C.

    2017-08-01

    The scope of this paper is the identification of an optimum technological solution for brazing aluminum alloys using crack tested specimens. To obtain conclusive results, these tests are conducted on two sets of different specimens. Thus, we get two sets of data which we will compare. These tests are part of the standardized series of tests required by the ASME standards. These are called exfoliation tests. They are used to determine where the crack occurs: in the base material or in the filler material. Thus, we can determine whether the cracking is cohesive or adhesive.

  8. Observations on infiltration of silicon carbide compacts with an aluminium alloy

    NASA Technical Reports Server (NTRS)

    Asthana, R.; Rohatgi, P. K.

    1992-01-01

    The melt infiltration of ceramic particulates permits an opportunity to observe such fundamental materials phenomena as nucleation, dynamic wetting and growth in constrained environments. Experimental observations are presented on the infiltration behavior and matrix microstructures that form when porous compacts of platelet-shaped single crystals of alpha- (hexagonal) silicon carbide are infiltrated with a liquid 2014 Al alloy. The infiltration process involved counter gravity infiltration of suitably tamped and preheated compacts of silicon carbide platelets under an external pressure in a special pressure chamber for a set period, then by solidification of the infiltrant metal in the interstices of the bed at atmospheric pressure.

  9. [Comporison Sduty of Microstructure by Metallographicalk on the Polarized Light and Texture by XRD of CC 5083 and CC 5182 Aluminium Alloy after Cold Rolling and Recrystallization].

    PubMed

    Chen, Ming-biao; Li, Yong-wei; Tan, Yuan-biao; Ma, Min; Wang, Xue-min; Liu, Wen-chang

    2015-03-01

    At present the study of relation between microstructure, texture and performance of CC 5083 aluminium alloy after cold tolling and recrystallization processes is still finitude. So that the use of the CC 5083 aluminium alloy be influenced. Be cased into electrical furnace, hot up with unlimited speed followed the furnace hot up to different temperature and annealed 2h respectively, and be cased into salt-beth furnace, hot up quickly to different temperature and annealed 30 min respectively for CC 5083 and CC 5182 aluminum alloy after cold roling with 91.5% reduction. The microstructure be watched use metallographic microscope, the texture be inspected by XRD. The start temperature of recrystallization and grain grow up temperature within annealing in the electric furnace of CC 5083 aluminum alloy board is 343 degrees C, and the shap of grain after grow up with long strip (the innovation point ); The start temperature of recrystallization within annealling in the salt bath furnace of CC 5083 is 343 degrees C. The start temperature and end temperature of recrystallization within annealling of CC 5083 and CC 5182 aluminum alloy is 371 degrees C. The grain grow up outstanding of cold rooled CC 5152 aluminum alloy after annealed with 454 degrees C in the electric furnace and salt bath furnace. The start temperature of grain grow up of CC 5083 alluminurn alloy annealed in the electric furnace and salt bath furnace respectively is higher than the start temperature of grain grow up of CC 5182 alluminum alloy annealed in the electric furnace and salt bath furnace respectively. The strat temperature of recrystallization grain grow up is higher than which annealled with other three manner annealing process. The recrystallization temperature of CC 5182 annealed in the salt bath furnace is higher than which annealed in the electric furnace. The recrystallization temperature of the surface layer of CC 5083 and CC 5182 aluminum alloy is higher than the inner layer (the innovation

  10. Fatigue properties of as-welded AA6005 and AA6082 aluminium alloys in T1 and T5 temper condition

    SciTech Connect

    Ranes, M.; Kluken, A.O.; Midling, O.T.

    1996-12-31

    The present investigation was undertaken to determine the as-welded fatigue properties of AA6005 and AA6082 aluminium alloys in the T1 and T5 temper conditions. Extruded flat bars of the base materials were welded by means of the Metal Inert Gas (MIG), Friction Stir and Plasma-keyhole techniques. The latter technique was only employed for alloy AA6005. The weldments were subsequently fatigue tested at a load ratio of 0.5. The results revealed that the friction stir welds had fatigue properties superior to both the MIG and Plasma-keyhole welds. For alloy AA6005 the fatigue properties of the friction stir weld was close to the base material properties. The shortest fatigue life was exhibited by the MIG welds. The fatigue strength of these weldments appear to be affected by the base metal temper condition. For this reason, MIG welds on alloy AA6082 should be performed in the T5 temper condition, while alloy AA6005 should be welded in the T1 temper condition. Plasma-keyhole welds should be performed on T1 tempered material rather than on T5 tempered material. Repair welding of MIG welds on the T1 tempered base material resulted in improved fatigue properties of AA6082 weldments, while the fatigue strength of AA6005 weldments remained unaffected. The fatigue properties of MIG welds in alloy AA6082 correspond well with the static strength properties.

  11. ``Long-life`` aluminium brazing alloys for automotive radiators -- a ten-year retrospective

    SciTech Connect

    Scott, A.C.; Woods, R.A.

    1998-12-31

    A class of corrosion-resistant brazing sheet materials, generally referred to as ``long-life alloys,`` has been in widespread use in brazed aluminum automobile radiators for over ten years. K319 tube material was initially introduced in 1986 to address the problem of road-salt-induced, outside-in corrosion of tubes in vacuum-brazed aluminum radiators, The development history, metallurgy, and field performance of long-life radiator brazing sheet are reviewed. This material utilizes the familiar sacrificial layer concept to improve corrosion resistance; however, it is unusual in that the layer is not introduced by conventional cladding means during sheet manufacture, but rather develops in situ by metallurgical transformations which occur during the brazing cycle. The sacrificial layer, about 25 mV anodic to the core alloy, increases by an order of magnitude the time-to-perforation of radiator tube sheet tested in cyclic acidified salt spray (SWAAT), which mimics the corrosion morphology observed in the field. Radiators examined after ten years of field service show excellent corrosion resistance, as predicted by SWAAT.

  12. Porosity evolution in additively manufactured aluminium alloy during high temperature exposure

    NASA Astrophysics Data System (ADS)

    Bai, J.; Ding, H. L.; Gu, J. L.; Wang, X. S.; Qiu, H.

    2017-01-01

    A 2319 aluminum alloy is deposited by the Wire+Arc Additive Manufacturing technology with Cold Metal Transfer process. Porosity that are both existing in the as-deposited and as-heat treated state metal are revealed by optical microscopy and quantitatively analyzed. It explains the reason why the newly initiated pores are easily tend to gather between each layer around the fusion line zone for the WAAM metal after heat treatment. The inner morphology of the pores are demonstrated by Scanning Electron Microscopy. Porosity evolution and distribution during high temperature exposure are demonstrated. Thus two porosity growth and number increase mechanisms are proposed eventually, providing theoretical basis for related material design and process optimization.

  13. On the melt infiltration of copper coated silicon carbide with an aluminium alloy

    NASA Technical Reports Server (NTRS)

    Asthana, R.; Rohatgi, P. K.

    1992-01-01

    Pressure-assisted infiltration of porous compacts of Cu coated and uncoated single crystals of platelet shaped alpha (hexagonal) SiC was used to study infiltration dynamics and particulate wettability with a 2014 Al alloy. The infiltration lengths were measured for a range of experimental variables which included infiltration pressure, infiltration time, and SiC size. A threshold pressure (P(th)) for flow initiation through compacts was identified from an analysis of infiltration data; P(th) decreased while penetration lengths increased with increasing SiC size (more fundamentally, due to changes in interparticle pore size) and with increasing infiltration times. Cu coated SiC led to lower P(th) and 60-80 percent larger penetration lengths compared to uncoated SiC under identical processing conditions.

  14. Aluminium plasmonics

    NASA Astrophysics Data System (ADS)

    Gérard, Davy; Gray, Stephen K.

    2015-05-01

    We present an overview of ‘aluminium plasmonics’, i.e. the study of both fundamental and practical aspects of surface plasmon excitations in aluminium structures, in particular thin films and metal nanoparticles. After a brief introduction noting both some recent and historical contributions to aluminium plasmonics, we discuss the optical properties of aluminium and aluminium nanostructures and highlight a few selected studies in a host of areas ranging from fluorescence to data storage.

  15. Aluminium plasmonics

    SciTech Connect

    Gerard, Davy; Gray, Stephen K.

    2014-12-15

    In this study, we present an overview of 'aluminium plasmonics', i.e. the study of both fundamental and practical aspects of surface plasmon excitations in aluminium structures, in particular thin films and metal nanoparticles. After a brief introduction noting both some recent and historical contributions to aluminium plasmonics, we discuss the optical properties of aluminium and aluminium nanostructures and highlight a few selected studies in a host of areas ranging from fluorescence to data storage.

  16. Aluminium plasmonics

    DOE PAGES

    Gerard, Davy; Gray, Stephen K.

    2014-12-15

    In this study, we present an overview of 'aluminium plasmonics', i.e. the study of both fundamental and practical aspects of surface plasmon excitations in aluminium structures, in particular thin films and metal nanoparticles. After a brief introduction noting both some recent and historical contributions to aluminium plasmonics, we discuss the optical properties of aluminium and aluminium nanostructures and highlight a few selected studies in a host of areas ranging from fluorescence to data storage.

  17. The effect of welding parameters on surface quality of AA6351 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Yacob, S.; MAli, M. A.; Ahsan, Q.; Ariffin, N.; Ali, R.; Arshad, A.; Wahab, M. I. A.; Ismail, S. A.; Roji, NS M.; Din, W. B. W.; Zakaria, M. H.; Abdullah, A.; Yusof, M. I.; Kamarulzaman, K. Z.; Mahyuddin, A.; Hamzah, M. N.; Roslan, R.

    2015-12-01

    In the present work, the effects of gas metal arc welding-cold metal transfer (GMAW-CMT) parameters on surface roughness are experimentally assessed. The purpose of this study is to develop a better understanding of the effects of welding speed, material thickness and contact tip to work distance on the surface roughness. Experiments are conducted using single pass gas metal arc welding-cold metal transfer (GMAW-CMT) welding technique to join the material. The material used in this experiment was AA6351 aluminum alloy with the thickness of 5mm and 6mm. A Mahr Marsuft XR 20 machine was used to measure the average roughness (Ra) of AA6351 joints. The main and interaction effect analysis was carried out to identify process parameters that affect the surface roughness. The results show that all the input process parameters affect the surface roughness of AA6351 joints. Additionally, the average roughness (Ra) results also show a decreasing trend with increased of welding speed. It is proven that gas metal arc welding-cold metal transfer (GMAW-CMT)welding process has been successful in term of providing weld joint of good surface quality for AA6351 based on the low value surface roughness condition obtained in this setup. The outcome of this experimental shall be valuable for future fabrication process in order to obtained high good quality weld.

  18. Investigation of surface finishing of carbon based coated tools for dry deep drawing of aluminium alloys

    NASA Astrophysics Data System (ADS)

    Steiner, J.; Andreas, K.; Merklein, M.

    2016-11-01

    Global trends like growing environmental awareness and demand for resource efficiency motivate an abandonment of lubricants in metal forming. However, dry forming evokes increased friction and wear. Especially, dry deep drawing of aluminum alloys leads to intensive interaction between tool and workpiece due to its high adhesion tendency. One approach to improve the tribological behavior is the application of carbon based coatings. These coatings are characterized by high wear resistance. In order to investigate the potential of carbon based coatings for dry deep drawing, friction and wear behavior of different coating compositions are evaluated in strip drawing tests. This setup is used to model the tribological conditions in the flange area of deep drawing operations. The tribological behavior of tetrahedral amorphous (ta-C) and hydrogenated amorphous carbon coatings with and without tungsten modification (a-C:H:W, a-C:H) is investigated. The influence of tool topography is analyzed by applying different surface finishing. The results show reduced friction with decreased roughness for coated tools. Besides tool topography the coating type determines the tribological conditions. Smooth tools with ta-C and a-C:H coatings reveal low friction and prevent adhesive wear. In contrast, smooth a-C:H:W coated tools only lead to slight improvement compared to rough, uncoated specimen.

  19. Elemental electron energy loss mapping of a precipitate in a multi-component aluminium alloy.

    PubMed

    Mørtsell, Eva A; Wenner, Sigurd; Longo, Paolo; Andersen, Sigmund J; Marioara, Calin D; Holmestad, Randi

    2016-07-01

    The elemental distribution of a precipitate cross section, situated in a lean Al-Mg-Si-Cu-Ag-Ge alloy, has been investigated in detail by electron energy loss spectroscopy (EELS) and aberration corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). A correlative analysis of the EELS data is connected to the results and discussed in detail. The energy loss maps for all relevant elements were recorded simultaneously. The good spatial resolution allows elemental distribution to be evaluated, such as by correlation functions, in addition to being compared with the HAADF image. The fcc-Al lattice and the hexagonal Si-network within the precipitates were resolved by EELS. The combination of EELS and HAADF-STEM demonstrated that some atomic columns consist of mixed elements, a result that would be very uncertain based on one of the techniques alone. EELS elemental mapping combined with a correlative analysis have great potential for identification and quantification of small amounts of elements at the atomic scale.

  20. Experimental and Numerical Study of Needle Peening Effects in Aluminium Alloy 2024-T3 Sheets

    NASA Astrophysics Data System (ADS)

    Mendez Romero, Julio Alberto

    Montreal as part of previous shot peening research. Saturation tests were done to determine the deflection at saturation for different peening parameters. The specimen deflection was measured using the standard Almen gauge used as part of routinary process control. Due to the aluminium magnetic incompatibility with the Almen gauge, the deformed specimen profile was measured using a Coordinate Measuring Machine (CMM). Repeatability of the process was demonstrated and the deflection at saturation, as well as the saturation time, was obtained. The indentation diameters created by impacts for different operating pressures were measured using microscopic photography. It was determined that the specimen deformation, as well as the indentation diameter, is larger when the operating pressure increases. Treatment of the test samples using the same peening parameters resulted in a variable indentation diameter. This is explained by the velocity variations detected during the equipment characterization. The added value that needle peening could provide to existing peening techniques is that, in principle, uniformity in the indentation diameters is easier to achieve as all impacts are normal and there is no loss of energy due to media interaction. The last experimental test was to determine the induced residual stress by means of X-ray Diffraction (XRD) for one specimen at saturation. An FE model heavily inspired by previous shot peening modeling was developed to simulate needle peening. The parameters obtained during the characterization of the equipment were taken as boundary conditions. Initially, the case of a single impacts was studied. Good accordance between the simulated and the average experimental indentation diameters was obtained, except for the lowest pressure studied. The overestimation of the indentation diameter could stem from the method used to measure the simulated diameter. Coverage estimation, and therefore indentation diameters remain an open line of research in

  1. Effects of processing parameters on the extrusion by continuous variable cross-section direct extrusion with 7A09 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Li, Feng; Wu, Hongbin; Qin, Minghan

    2016-02-01

    In order to study the effects of processing parameters on the continuous variable cross-section direct extrusion (CVCDE), taking 7A09 aluminium alloy for example, the extrusion speed and forming temperature and the friction factor as key processing parameters are applied to research by finite element (FE) simulation. The research result showed that the extrusion speed had a significant influence on the maximum temperature of the billet, at the same time, both decreasing the friction factor and increasing forming temperature within a certain range were beneficial to reduce extrusion load. Both forming temperature and the extrusion speed were inversely linked to extrusion load, but the friction factor was directly proportional to extrusion load. Forming temperature had a far more important influence on extrusion load by comparison: when forming temperature increased from 380∘ to 430∘C, the peak value of extrusion load decreased by 25.6% and the flow uniformity of extruded product got improved. The process window based on both the press limit and surface defects limit was established and the most reasonable forming temperature was 405∘C under this process condition, which provided theoretical basis for formulation process of 7A09 aluminium alloy on the CVCDE extrusion.

  2. The effects of short pulse laser surface cleaning on porosity formation and reduction in laser welding of aluminium alloy for automotive component manufacture

    NASA Astrophysics Data System (ADS)

    AlShaer, A. W.; Li, L.; Mistry, A.

    2014-12-01

    Laser welding of aluminium alloys typically results in porosity in the fusion zones, leading to poor mechanical and corrosion performances. Mechanical and chemical cleaning of surfaces has been used previously to remove contaminants for weld joint preparations. However, these methods are slow, ineffective (e.g. due to hydrogen trapping) or lead to environmental hazards. This paper reports the effects of short pulsed laser surface cleaning on porosity formation and reduction in laser welding of AC-170PX (AA6014) aluminium sheets (coated with Ti/Zr and lubricated using a dry lubricant AlO70) with two types of joints: fillet edge and flange couch, using an AA4043 filler wire for automotive component assembly. The effect of laser cleaning on porosity reduction during laser welding using a filler wire has not been reported before. In this work, porosity and weld fusion zone geometry were examined prior to and after laser cleaning. The nanosecond pulsed Nd:YAG laser cleaning was found to reduce porosity significantly in the weld fusion zones. For the fillet edge welds, porosity was reduced to less than 0.5% compared with 10-80% without laser cleaning. For flange couch welds, porosity was reduced to 0.23-0.8% with laser cleaning from 0.7% to 4.3% without laser cleaning. This has been found to be due to the elimination of contaminations and oxide layers that contribute to the porosity formation. The laser cleaning is based on thermal ablation. This research focuses on porosity reduction in laser welding of aluminium alloy. Weld quality was investigated for two joints, fillet edge and flange couch joints. The effect of laser cleaning on porosity reduction after welding was investigated. It was found that laser cleaning reduced porosity less than 1% in both joints. Weld dimensions and strength were evaluated and discussed for both types of joints.

  3. Design and operation of an aluminium alloy tank using doped Na3AlH6 in kg scale for hydrogen storage

    NASA Astrophysics Data System (ADS)

    Urbanczyk, R.; Peinecke, K.; Meggouh, M.; Minne, P.; Peil, S.; Bathen, D.; Felderhoff, M.

    2016-08-01

    In this publication the authors present an aluminium alloy tank for hydrogen storage using 1921 g of Na3AlH6 doped with 4 mol% of TiCl3 and 8 mol% of activated carbon. The tank and the heat exchangers are manufactured by extrusion moulding of Al-Mg-Si based alloys. EN AW 6082 T6 alloy is used for the tank and a specifically developed alloy with a composition similar to EN AW 6060 T6 is used for the heat exchangers. The three heat exchangers have a corrugated profile to enhance the surface area for heat transfer. The doped complex hydride Na3AlH6 is densified to a powder density of 0.62 g cm-3. The hydrogenation experiments are carried out at 2.5 MPa. During one of the dehydrogenation experiments approximately 38 g of hydrogen is released, accounting for gravimetric hydrogen density of 2.0 mass-%. With this tank 15 hydrogenation and 16 dehydrogenation tests are carried out.

  4. The Influence of Strain Rate Variations on the Appearance of Serrated Yielding in 2024-T3 Al-Clad Aluminium Alloy

    SciTech Connect

    Leacock, Alan G.; McMurray, Robert J.; Brown, D.; Poston, Ken

    2007-04-07

    To avoid failure during the stretch forming process using manual control, machine operators tend to achieve the final form using a stop-start approach. It was observed that when approaching full form, stretcher-strain marks appeared on the surface of the part if the operator stopped and restarted the forming operation. In order to investigate this phenomenon, a series of tensile tests was conducted using two batches of 2024-T3 aluminium alloy. The specimens were tested using several different strain rates, representative of those used on the shop floor. Additional tests were conducted involving a series of pauses under displacement control at differing levels of strain and strain rate. In the uninterrupted tests for the two batches of 2024-T3 material tested, serrated yielding was observed just prior to failure. However for the tests in which there was a pause in displacement, the material consistently exhibited serrated yielding when the crosshead began to move again. These results indicate that the pause provides an opportunity for strain ageing and pinning of the dislocations resulting in serrated yielding of this alloy. In order to avoid serrated yielding, stretch forming operations using 2024-T3 aluminium should be conducted at a constant strain rate without interruption. This also has far reaching implications for those involved in the production and testing of these alloys. The test programme described represents an initial attempt to investigate a phenomenon noted during an industrial forming process and should be extended to analyse the affect of strain path changes on the occurrence of serrated yielding.

  5. Experiment-based modelling of grain boundary β-phase (Mg2Al3) evolution during sensitisation of aluminium alloy AA5083.

    PubMed

    Zhang, R; Steiner, M A; Agnew, S R; Kairy, S K; Davies, C H J; Birbilis, N

    2017-06-07

    An empirical model for the evolution of β-phase (Mg2Al3) along grain boundaries in aluminium alloy AA5083 (Al-Mg-Mn) during isothermal exposures is proposed herein. Developing a quantitative understanding of grain boundary precipitation is important to interpreting intergranular corrosion and stress corrosion cracking in this alloy system. To date, complete ab initio models for grain boundary precipitation based upon fundamental principles of thermodynamics and kinetics are not available, despite the critical role that such precipitates play in dictating intergranular corrosion phenomena. Empirical models can therefore serve an important role in advancing the understanding of grain boundary precipitation kinetics, which is an approach applicable beyond the present context. High resolution scanning electron microscopy was to quantify the size and distribution of β-phase precipitates on Ga-embrittled intergranular fracture surfaces of AA5083. The results are compared with the degree of sensitisation (DoS) as judged by nitric acid mass loss testing (ASTM-G67-04), and discussed with models for sensitisation in 5xxx series Al-alloys. The work herein allows sensitisation to be quantified from an unambiguous microstructural perspective.

  6. Some preliminary evaluations of black coating on aluminium AA2219 alloy produced by plasma electrolytic oxidation (PEO) process for space applications

    NASA Astrophysics Data System (ADS)

    Shrestha, S.; Merstallinger, A.; Sickert, D.; Dunn, B. D.

    2003-09-01

    This paper describes the results of a study of a black coating produced on aluminium AA2219 alloy using a process that involves creation of a hard ceramic oxide layer on the surface of the alloy by plasma electrolytic oxidation (PEO) known as the 'KERONITE®' process. Coating microstructure has been examined and the coating characteristics such as porosity, hardness, adhesion and phase composition were measured. The thermo-optical properties such as solar absorptance 'as' and normal infrared emittance 'en-IR' of the coating were measured in the 'as-prepared' condition and after environmental exposures to humidity, thermal cycling and UV-radiation in vacuum and to thermal shock. Comparison was made with alternative coatings produced using standard black anodising processes. The study also looked at the cold welding and friction behaviours of the coated alloy in vacuum and in an ambient laboratory environment. Standard spacecraft materials tests were conducted on the coated disc against an AISI 52100 steel ball and also against a coated pin using a pin-on-disc apparatus. Parameters such as friction coefficient and wear depth were measured and the cold welding behaviours were investigated. Test results were compared with the data generated for NiCr plated and anodised coatings. Corrosion performance was assessed using a salt spray exposure test and using an accelerated electrochemical test method. In addition, the study looked at the effect of post coating sealing with a sol-gel solution.

  7. Finite element modelling of shot peening and peen forming processes and characterisation of peened AA2024-T351 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Gariepy, Alexandre

    The main purpose of this thesis was to develop and validate finite element (FE) simulation tools for shot peening and peen forming. The specific aim was to achieve quantitatively accurate predictions for both processes and demonstrate the potential of reliable FE modelling for scientific investigation and industrial applications. First, an improved dynamic impact model that takes into account the stochastic nature of shot peening was proposed by carefully studying its dimensions, introducing a dispersion of shot sizes and significantly reducing its computational cost. In addition, cyclic mechanical testing was conducted to define a suitable material constitutive theory for aluminium alloy (AA) 2024-T3/T351 subjected to shot peening. By combining a realistic shot peening model with an appropriate material law, fairly good residual stress predictions were achieved for three different sets of shot peening parameters. Second, an experimental and numerical characterization of AA2024-T351 shot peened with parameters representative of fatigue life improvement applications was conducted. Multiple techniques, such as micro-indentation, residual stress determination and electron backscatter diffraction, were combined to gain a better understanding of the influence of shot peening on the material. The potential uses of finite element simulation to complement experimental data were also studied. The material heterogeneity arising from the random impact sequence was investigated and it was found that the impact modelling methodology could provide useful information on such heterogeneities. Third, a novel peen forming simulation methodology was introduced. The impact model provided the necessary input data as part of a multiscale approach. Numerically calculated unbalanced induced stress profiles were input into shell elements and the deformed shape after peen forming was computed as a springback analysis. In addition, a simple interpolation method was proposed to model the

  8. Extraction spectrophotometric determination of vanadium in natural waters and aluminium alloys using pyridyl azo resorcinol (PAR) and iodo-nitro-tetrazolium chloride (INT).

    PubMed

    Gavazov, K; Simeonova, Z; Alexandrov, A

    2000-06-30

    Extraction-spectrophotometric methods are developed for the determination of vanadium content in natural waters and aluminium alloys. They are based on the formation and subsequent extraction into chloroform of the ternary ion association complex of V(V) with PAR and INT in the presence of CDTA and NH(4)F as masking agents. Optimum pH range of the reaction is 5.5-7.5. Maximum absorbance of the extracted complex is at 560 nm. The method for determination of V(V) in drinking waters can be successfully applied at a concentration level of 3 ppb and higher without additional pre-concentration. Among studied more than 30 foreign ions potentially present in natural waters only Ca(II) can interfere. It is removed by precipitation as CaF(2) and filtration. A 40-fold excess of V(IV) does not interfere with determination of V(V) and can also be determined indirectly (after oxidation to V(V)). The proposed method is applied to analysis of model mixtures as well as to the analysis of tap and mineral waters. Beer's law is obeyed for up to 15 mug of V(V) in 40 ml aqueous phase. The accuracy and precision are reasonable. The RSD is in the range 6.5-23.2% for determination of 6.3 ppb V(V). The procedure for analysis of aluminium alloys differs from the procedure for analysis of waters by the order of introduction of the reagents. The macrocomponent does not interfere and is not separated. Mg, Mn, Cu, Zn, Fe, Cr, Ti and Zr do not interfere. A 25-fold excess of Ni interferes. The method is tested in the analysis of reference standards containing 0.005 and 0.007% V, respectively. The RSD is 1.4%.

  9. The effect of surface pre-conditioning treatments on the local composition of Zr-based conversion coatings formed on aluminium alloys

    NASA Astrophysics Data System (ADS)

    Cerezo, J.; Vandendael, I.; Posner, R.; de Wit, J. H. W.; Mol, J. M. C.; Terryn, H.

    2016-03-01

    This study investigates the effect of different alkaline, acidic and thermal pre-conditioning treatments applied to different Al alloy surfaces. The obtained results are compared to the characteristics of Zr-based conversion coatings that were subsequently generated on top of these substrates. Focus is laid on typical elemental distributions on the sample surfaces, in particular on the amount of precipitated functional additives such as Cu species that are present in the substrate matrix as well as in the conversion bath solutions. To this aim, Field Emission Auger Electron spectra, depth profiles and surface maps with superior local resolution were acquired and compared to scanning electron microscopy images of the sample. The results show how de-alloying processes, which occur at and around intermetallic particles in the Al matrix during typical industrial alkaline or acidic cleaning procedures, provide a significant source of crystallization cores for any following coating processes. This is in particular due for Cu-species, as the resulting local Cu structures on the surface strongly affect the film formation and compositions of state-of-the-art Zr-based films. The findings are highly relevant for industrial treatments of aluminium surfaces, especially for those that undergo corrosion protection and painting process steps prior to usage.

  10. Increasing strength, ductility and impact toughness of ultrafine-grained 6063 aluminium alloy by combining ECAP and a high-temperature short-time aging

    NASA Astrophysics Data System (ADS)

    Meyer, L. W.; Schönherr, R.; Hockauf, M.

    2010-07-01

    Since fully-dense ultrafine or nanocrystalline bulk materials can be processed, there has been an increasing scientific interest in several plastic deformation (SPD) procedures, particularly in the last decade. Especially the equal-channel angular pressing (ECAP) has widely been investigated due to its ability of producing billets sufficiently large for industrial applications in functional or structural components. The significant strength increase based on grain refinement is typically accompanied by a significant decrease in ductility and toughness. Within this work, a new methodology was applied for combining ECAP with a subsequent high-temperature short-time aging for the 6063 aluminium alloy. An increase in strength, ductility as well as impact toughness regarding its coarse grained counterparts was reached. More precisely, ultimate tensile strength, elongation to failure and impact toughness were increased by 46%, 21% and 40% respectively. This was observed after only one run of ECAP at room temperature in a solid-solution treated condition and an aging at 170° C for 18 minutes. The regular aging time for maximum strength at 170° C is around 6 hours. Longer exposure times lead to recrystallisation and, as for regular aging, it leads to overaging, both causing a decrease of properties. The work demonstrates a strategy for an efficient processing of commercial Al-Mg-Si alloys with outstanding mechanical properties.

  11. Electron Conditioning of Technical Aluminium Surfaces

    SciTech Connect

    Le Pimpec, F

    2004-09-02

    The effect of electron conditioning on commercially aluminium alloys 1100 and 6063 were investigated. Contrary to the assumption that electron conditioning, if performed long enough, can reduce and stabilize the SEY to low values (= 1.3, value of many pure elements [1]), the SEY of aluminium did not go lower than 1.8. In fact, it reincreases with continued electron exposure dose.

  12. Real-time synchrotron x-ray observations of equiaxed solidification of aluminium alloys and implications for modelling

    NASA Astrophysics Data System (ADS)

    Prasad, A.; Liotti, E.; McDonald, S. D.; Nogita, K.; Yasuda, H.; Grant, P. S.; StJohn, D. H.

    2015-06-01

    Recently, in-situ observations were carried out by synchrotron X-ray radiography to observe the nucleation and growth in Al alloys during solidification. The nucleation and grain formation of a range of Al-Si and Al-Cu binary alloys were studied. When grain refiner was added to the alloys, the location of the nucleation events was readily observed. Once nucleation began it continued to occur in a wave of events with the movement of the temperature gradient across the field of view due to cooling. Other features observed were the settling of the primary phase grains in the Al-Si alloys and floating in the Al-Cu alloys, the effects of convection with marked fluctuation of the growth rate of the solid-liquid interface in the Al-Si alloys, and an absence of fragmentation. The microstructures are typical of those produced in the equiaxed zone of actual castings. These observations are compared with predictions arising from the Interdependence model. The results from this comparison have implications for further refinement of the model and simulation and modelling approaches in general. These implications will be discussed.

  13. Effects of quench rate and natural ageing on the age hardening behaviour of aluminium alloy AA6060

    SciTech Connect

    Strobel, Katharina; Lay, Matthew D.H.; Easton, Mark A.; Sweet, Lisa; Zhu, Suming; Parson, Nick C.; Hill, Anita J.

    2016-01-15

    Quench sensitivity in Al–Mg–Si alloys has been largely attributed to the solute loss at the heterogeneous nucleation sites, primarily dispersoids, during slow cooling after extrusion. As such, the number density of dispersoids, the solute type and concentration are considered to be the key variables for the quench sensitivity. In this study, quench sensitivity and the influence of natural ageing in a lean Al–Mg–Si alloy, AA6060, which contains few dispersoids, have been investigated by hardness measurement, thermal analysis, transmission electron microscopy (TEM) and positron annihilation lifetime spectroscopy (PALS). It is shown that the quench sensitivity in this alloy is associated with the degree of supersaturation of vacancies after cooling. Due to vacancy annihilation and clustering during natural ageing, the quench sensitivity is more pronounced after a short natural ageing time (30 min) compared to a longer natural ageing time (24 h). Therefore, prolonged natural ageing not only leads to an increase in hardness, but can also have a positive effect on the quench sensitivity of lean Al–Mg–Si alloys. - Highlights: • Significant quench sensitivity observed in AA6060 alloy after 30 min natural ageing • Prolonged natural ageing increased hardness and reduced QS. • Low dispersoid density leads to insignificant QS from non-hardening precipitates. • Vacancy supersaturation identified as a contributor to QS.

  14. Influences of process parameters on tensile strength of friction stir welded cast A319 aluminium alloy joints

    NASA Astrophysics Data System (ADS)

    Jayaraman, M.; Sivasubramanian, R.; Balasubramanian, V.; Babu, S.

    2009-04-01

    Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking. Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at four levels. The quality of weld zone was analyzed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone microstructure. The joint fabricated with a 1200 rpm tool rotation speed, 40 mm/min welding speed, and 4 kN axial force showed superior tensile strength compared with the other joints.

  15. A Fundamental Approach to Developing Aluminium based Bulk Amorphous Alloys based on Stable Liquid Metal Structures and Electronic Equilibrium - 154041

    DTIC Science & Technology

    2017-03-28

    amorphous (glassy) atomic structure as opposed to an ordered crystalline structure found in regular alloys.[1] These exciting new materials have received...crystallization kinetics when cooling from the molten state may be achieved topologically by having dense atomic packing configurations within the liquid...structure which jams or severely hinders atomic movement/diffusion.[4] DISTRIBUTION A. Approved for public release: distribution unlimited

  16. Microstructures and hardness of stir zone for friction stir processed and post-processed heat treatment 7B04-O aluminium alloy

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Ding, H.; Li, J. Z.

    2017-05-01

    Friction stir processing (FSP) with different rotation speeds was conducted on 7B04-O aluminium alloy thin-sheet, then the post-processed heat treatment (PPHT) was carried out. The microstructures and hardness of the stir zone (SZ) under as-processed (AP) and PPHT states were investigated. The result showed that the hardness of the SZ was enhanced under the AP state, attributing to the grain refinement. The effect of PPHT on the hardness of the material was different, compared with the AP state, the hardness of the SZ with a low rotation speed under PPHT state was deteriorated while it was enhanced when high rotation speed was adopted. When FSP was conducted on the O-temper base metal (BM), the initial precipitates in the matrix were coarse and stable, reducing the dissolution rate of the precipitates. High heat input was required in order to induce sufficient dissolution of the precipitates, which was beneficial to elevating the impact of PPHT on hardness. The amount and morphology of the precipitates played important roles in the SZ of improvement in hardness.

  17. Comparison of fatigue crack growth of riveted and bonded aircraft lap joints made of Aluminium alloy 2024-T3 substrates - A numerical study

    NASA Astrophysics Data System (ADS)

    Pitta, S.; Rojas, J. I.; Crespo, D.

    2017-05-01

    Aircraft lap joints play an important role in minimizing the operational cost of airlines. Hence, airlines pay more attention to these technologies to improve efficiency. Namely, a major time consuming and costly process is maintenance of aircraft between the flights, for instance, to detect early formation of cracks, monitoring crack growth, and fixing the corresponding parts with joints, if necessary. This work is focused on the study of repairs of cracked aluminium alloy (AA) 2024-T3 plates to regain their original strength; particularly, cracked AA 2024-T3 substrate plates repaired with doublers of AA 2024-T3 with two configurations (riveted and with adhesive bonding) are analysed. The fatigue life of the substrate plates with cracks of 1, 2, 5, 10 and 12.7mm is computed using Fracture Analysis 3D (FRANC3D) tool. The stress intensity factors for the repaired AA 2024-T3 plates are computed for different crack lengths and compared using commercial FEA tool ABAQUS. The results for the bonded repairs showed significantly lower stress intensity factors compared with the riveted repairs. This improves the overall fatigue life of the bonded joint.

  18. Micro-scratching tests of a rolled aluminium alloy AA2024-T351 thick plate using a diamond micro-blade

    NASA Astrophysics Data System (ADS)

    Pirva, E.; Tudor, A.; Gavrus, A.; Chisiu, G.; Stoica, N.; Predescu, A.

    2017-02-01

    The present research work is focused on investigating the apparent coefficient of abrasive friction of a rolled thick plate of an AA2024-T351 aluminium alloy, using micro-scratch tests. For this study, specific materials specimens and a particular UMT Micro-Scratch Equipment were used. The test involved the generation of a scratch process at a local scale using a diamond stylus (micro-blade defined by a radius of 0.8 μm) moving along a specified path under a constant normal force (10 N) and with a constant speed (0.2 mm/s). For the characterization of the surface quality, two orthogonal directions were considered: the longitudinal one, along the rolling direction, and the corresponding transversal one. Given the fractal nature of the surface, an investigation was done in order to assess its influence on the coefficient of abrasive friction. The fractal dimension Df, one of the most important parameters in a fractal surface analysis, was used to determine this influence in the global friction and abrasion phenomena. The abrasion factor was calculated using the Zum Gahr method for the data obtained with a specialized Mitutoyo SJ-301 surface tester. Measurements were made at the beginning, middle and at the end of the scratch channel. The obtained value for the abrasion factor was slightly less than zero. Other influences of anisotropic material features on global abrasion effects were also analyzed via comparisons of the coefficients of abrasive friction for both static and kinematic conditions.

  19. The attack of titanium-6 wt% aluminium-4 wt% vanadium alloy by a molten uranium-5.7 wt% manganese alloy at 1015 °C

    NASA Astrophysics Data System (ADS)

    Moran, F. J.; Jarman, R. A.

    1991-06-01

    The liquid metal corrosion (LMC) resistance of the alloy Ti-6 wt% Al-4 wt% V (IMI 318) in contact with molten U-5.7 wt% Mn has been assessed. The uranium alloy was melted at 1015 °C under vacuum in hemispherical IMI 318 alloy crucibles. The attack rate of the molten alloy on the IMI 318, for times up to 3 h, was estimated from metallography and by chemical analysis of the resolidified uranium melt. The mechanism of the LMC process was examined with optical and electron microscopy allied with EDAX and microhardness tests. Melt saturation occurred after one hour and titanium-rich (approximately 80 wt% Ti) dendrites began to nucleate and grow in the uranium melt. This result was predicted by the relevant equilibrium phase diagrams. During the LMC reaction, an interface (diffusion) layer grew in IMI 318 alloy where it contacted the uranium alloy melt. The levels of Ti and U changed with test time and distance across this interface, with the Ti level falling at the melt/IMI 318 surface and the U increasing at the same point. The mean LMC rate was initially rapid, 1.45 mm/h after 15 min but fell to 0.3 mm/h at 3 h. The conclusions were that the LMC reaction was diffusion-controlled, with the slow self-diffusion of β-titanium most likely to be the rate determining step. The reaction probably follows parabolic rate-kinetics as do other diffusion-controlled processes. The attack front was generally uniform with no clear evidence of preferential attack.

  20. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357)

    NASA Astrophysics Data System (ADS)

    Alexopoulos, N. D.

    2010-06-01

    The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  1. Microstructural evolution and age hardening in aluminium alloys: Atom probe field-ion microscopy and transmission electron microscopy studies

    SciTech Connect

    Ringer, S.P.; Hono, K.

    2000-02-01

    This paper examines the microstructural evolution in selected aluminum alloys based on commercial age hardenable 2000, 6000, and 7000 series alloys. Atom probe field-ion microscopy and transmission electron microscopy have been used to examine the effects of microalloying and the origins of hardening. The combined application of these techniques is particularly important in the study of nanoscale precipitation processes. It is shown that the nature and kinetics of the precipitation process depend on the solute-solute interactions that produce solute clusters. The solute clusters precede the formation of GP zones or precipitation, and have a defining role on the nature and kinetics of the subsequent precipitation processes. Moreover, interactions between solute clustering and dislocations can have a significant hardening effect, the origins of which seem to be distinctly different from the conventional notion of precipitation hardening.

  2. Investigation impact of stressed state conditions and thermomechanical parameters on the texture and structure evolution in 1565ph aluminium alloy

    NASA Astrophysics Data System (ADS)

    Yashin, V. V.; Aryshensky, E. V.; Kawalla, R. F.; Serebryany, V. N.; Rushchits, S. V.

    2016-11-01

    The paper is devoted to study of the impact stress condition and thermomechanical treatment parameters on the structure and texture evolution of new 1565 ph aluminum alloy. For that purposes, we use test on Gleeble equipment, FM calculation, optical microscopy and x ray diffraction texture analysis. The dependency between the deformation texture components development and strain rate value was established. Differences in the texture evolution at uniaxial compression stress and plain strain mode were revealed.

  3. Fatigue FEM analysis in the case of brazed aluminium alloy 3L59 used in aeronautical industry

    NASA Astrophysics Data System (ADS)

    Dimitrescu, A.; Amza, Gh; Niţoi, D. F.; Amza, C. Gh; Apostolescu, Z.

    2016-08-01

    The use, on a larger scale, of brazed aluminum alloys in the aerospace industry led to the need for a detailed study of the assemblies behavior. These are built from 6061 aluminum aloy (3L59) brazed with aluminum aloy A103. Therefore, a finit element simulation (FEM) of durability is necessary, that consists in the observation of gradual deterioration until failure. These studies are required and are previous to the stage of the producing the assembly and test it by traditional methods.

  4. Cube texture formation during the early stages of recrystallization of Al-1%wt.Mn and AA1050 aluminium alloys

    NASA Astrophysics Data System (ADS)

    Miszczyk, M. M.; Paul, H.

    2015-08-01

    The cube texture formation during primary recrystallization was analysed in plane strain deformed samples of a commercial AA1050 alloy and an Al-1%wt.Mn model alloy single crystal of the Goss{110}<001> orientation. The textures were measured with the use of X-ray diffraction and scanning electron microscopy equipped with an electron backscattered diffraction facility. After recrystallization of the Al-1%wt.Mn single crystal, the texture of the recrystallized grains was dominated by four variants of the S{123}<634> orientation. The cube grains were only sporadically detected by the SEM/EBSD system. Nevertheless, an increased density of <111> poles corresponding to the cube orientation was observed. The latter was connected with the superposition of four variants of the S{123}<634> orientation. This indicates that the cube texture after the recrystallization was a ‘compromise texture’. In the case of the recrystallized AA1050 alloy, the strong cube texture results from both the increased density of the particular <111> poles of the four variants of the S orientation and the ∼40°(∼< 111>)-type rotation. The first mechanism transforms the Sdef-oriented areas into Srex ones, whereas the second the near S-oriented, as-deformed areas into near cube-oriented grains.

  5. Investigation of the aluminium-aluminium oxide reversible transformation as observed by hot stage electron microscopy.

    NASA Technical Reports Server (NTRS)

    Grove, C. A.; Judd, G.; Ansell, G. S.

    1972-01-01

    Thin foils of high purity aluminium and an Al-Al2O3 SAP type of alloy were oxidised in a specially designed hot stage specimen chamber in an electron microscope. Below 450 C, amorphous aluminium oxide formed on the foil surface and was first detectable at foil edges, holes, and pits. Islands of aluminium then nucleated in this amorphous oxide. The aluminium islands displayed either a lateral growth with eventual coalescence with other islands, or a reoxidation process which caused the islands to disappear. The aluminium island formation was determined to be related to the presence of the electron beam. A mechanism based upon electron charging due to the electron beam was proposed to explain the nucleation, growth, coalescence, disappearance, and geometry of the aluminium islands.

  6. A thermomechanical analysis of sticking-sliding zones at the tool-chip interface in dry high-speed machining of aluminium alloy A2024-T351: A hybrid Analytical-Fe model

    NASA Astrophysics Data System (ADS)

    Avevor, Y.; Moufki, A.; Nouari, M.

    2016-10-01

    In high speed dry machining of aluminium alloy (A2024-T351), the tribological conditions at the tool-chip interface strongly affect the thermomechanical process of chip formation, the tool wear and the surface integrity. In order to contribute to the understanding of the effect of friction conditions, a hybrid Analytical-FE model is presented. The transient nonlinear thermal problem in the tool-chip-workpiece system is solved by using a Petrov-Galerkin finite element model. To illustrate the model results, the relationship between the local friction coefficient, in the sliding zone, and the apparent friction coefficient, which takes into account the whole tool-chip contact, is presented.

  7. Parameter Design in Fusion Welding of AA 6061 Aluminium Alloy using Desirability Grey Relational Analysis (DGRA) Method

    NASA Astrophysics Data System (ADS)

    Adalarasan, R.; Santhanakumar, M.

    2015-01-01

    In the present work, yield strength, ultimate strength and micro-hardness of the lap joints formed with Al 6061 alloy sheets by using the processes of Tungsten Inert Gas (TIG) welding and Metal Inert Gas (MIG) welding were studied for various combinations of the welding parameters. The parameters taken for study include welding current, voltage, welding speed and inert gas flow rate. Taguchi's L9 orthogonal array was used to conduct the experiments and an integrated technique of desirability grey relational analysis was disclosed for optimizing the welding parameters. The ignored robustness in desirability approach is compensated by the grey relational approach to predict the optimal setting of input parameters for the TIG and MIG welding processes which were validated through the confirmation experiments.

  8. Comparison between diffraction contrast tomography and high-energy diffraction microscopy on a slightly deformed aluminium alloy.

    PubMed

    Renversade, Loïc; Quey, Romain; Ludwig, Wolfgang; Menasche, David; Maddali, Siddharth; Suter, Robert M; Borbély, András

    2016-01-01

    The grain structure of an Al-0.3 wt%Mn alloy deformed to 1% strain was reconstructed using diffraction contrast tomography (DCT) and high-energy diffraction microscopy (HEDM). 14 equally spaced HEDM layers were acquired and their exact location within the DCT volume was determined using a generic algorithm minimizing a function of the local disorientations between the two data sets. The microstructures were then compared in terms of the mean crystal orientations and shapes of the grains. The comparison shows that DCT can detect subgrain boundaries with disorientations as low as 1° and that HEDM and DCT grain boundaries are on average 4 µm apart from each other. The results are important for studies targeting the determination of grain volume. For the case of a polycrystal with an average grain size of about 100 µm, a relative deviation of about ≤10% was found between the two techniques.

  9. Comparison between diffraction contrast tomography and high-energy diffraction microscopy on a slightly deformed aluminium alloy

    PubMed Central

    Renversade, Loïc; Quey, Romain; Ludwig, Wolfgang; Menasche, David; Maddali, Siddharth; Suter, Robert M.; Borbély, András

    2016-01-01

    The grain structure of an Al–0.3 wt%Mn alloy deformed to 1% strain was reconstructed using diffraction contrast tomography (DCT) and high-energy diffraction microscopy (HEDM). 14 equally spaced HEDM layers were acquired and their exact location within the DCT volume was determined using a generic algorithm minimizing a function of the local disorientations between the two data sets. The microstructures were then compared in terms of the mean crystal orientations and shapes of the grains. The comparison shows that DCT can detect subgrain boundaries with disorientations as low as 1° and that HEDM and DCT grain boundaries are on average 4 µm apart from each other. The results are important for studies targeting the determination of grain volume. For the case of a polycrystal with an average grain size of about 100 µm, a relative deviation of about ≤10% was found between the two techniques. PMID:26870379

  10. Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology.

    PubMed

    Kumar Dalapati, Goutam; Masudy-Panah, Saeid; Kumar, Avishek; Cheh Tan, Cheng; Ru Tan, Hui; Chi, Dongzhi

    2015-12-03

    This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm(2), and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p(+-)n homojunction through the formation of re-grown crystalline silicon layer (~5-10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method.

  11. Electron irradiation of aluminium-zinc alloys. 1. Radiation-induced segregation in an aluminum-0.35 at% zinc alloy

    NASA Astrophysics Data System (ADS)

    Zhang, Y. G.; Jones, I. P.

    1989-06-01

    Enrichment of zinc atoms at grain boundaries and depletion in the area irradiated with a condensed electron beam occurred in quite short irradiation times in an Al-0.35 at% Zn alloy. The segregation rate increased up to a maximum at 160°C and thereafter decreased as the temperature increased. Enrichment of Zn atoms at grain boundaries is due to a flux of interstitial-zinc atom complexes to the boundaries and depletion in the irradiated area is similarly ascribed to a flux of interstitial-zinc atom complexes down the damage rate gradient. In an intermediate temperature range, the two phenomena have different dependencies on temperature: this is ascribed to the effect of foil surface diffusion.

  12. Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology

    PubMed Central

    Kumar Dalapati, Goutam; Masudy-Panah, Saeid; Kumar, Avishek; Cheh Tan, Cheng; Ru Tan, Hui; Chi, Dongzhi

    2015-01-01

    This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm2, and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p+−n homojunction through the formation of re-grown crystalline silicon layer (~5–10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method. PMID:26632759

  13. Aluminium in human sweat.

    PubMed

    Minshall, Clare; Nadal, Jodie; Exley, Christopher

    2014-01-01

    It is of burgeoning importance that the human body burden of aluminium is understood and is measured. There are surprisingly few data to describe human excretion of systemic aluminium and almost no reliable data which relate to aluminium in sweat. We have measured the aluminium content of sweat in 20 healthy volunteers following mild exercise. The concentration of aluminium ranged from 329 to 5329μg/L. These data equate to a daily excretion of between 234 and 7192μg aluminium and they strongly suggest that perspiration is the major route of excretion of systemic aluminium in humans. Copyright © 2013 Elsevier GmbH. All rights reserved.

  14. Evidence of aluminium accumulation in aluminium welders.

    PubMed Central

    Elinder, C G; Ahrengart, L; Lidums, V; Pettersson, E; Sjögren, B

    1991-01-01

    Using atomic absorption spectrometry the aluminium concentrations in blood and urine and in two iliac bone biopsies obtained from welders with long term exposure to fumes containing aluminium were measured. The urinary excretion of two workers who had welded for 20 and 21 years varied between 107 and 351 micrograms Al/l, more than 10 times the concentration found in persons without occupational exposure. Urinary aluminium excretion remained high many years after stopping exposure. Blood and bone aluminium concentrations (4-53 micrograms Al/l and 18-29 micrograms Al/g respectively) were also raised but not to the same extent as urine excretion. It is concluded that long term exposure to aluminium by inhalation gives rise to accumulation of aluminium in the body and skeleton of health persons, and that the elimination of retained aluminium is very slow, in the order of several years. PMID:1954151

  15. IEC 61267: Feasibility of type 1100 aluminium and a copper/aluminium combination for RQA beam qualities.

    PubMed

    Leong, David L; Rainford, Louise; Zhao, Wei; Brennan, Patrick C

    2016-01-01

    In the course of performance acceptance testing, benchmarking or quality control of X-ray imaging systems, it is sometimes necessary to harden the X-ray beam spectrum. IEC 61267 specifies materials and methods to accomplish beam hardening and, unfortunately, requires the use of 99.9% pure aluminium (Alloy 1190) for the RQA beam quality, which is expensive and difficult to obtain. Less expensive and more readily available filters, such as Alloy 1100 (99.0% pure) aluminium and copper/aluminium combinations, have been used clinically to produce RQA series without rigorous scientific investigation to support their use. In this paper, simulation and experimental methods are developed to determine the differences in beam quality using Alloy 1190 and Alloy 1100. Additional simulation investigated copper/aluminium combinations to produce RQA5 and outputs from this simulation are verified with laboratory tests using different filter samples. The results of the study demonstrate that although Alloy 1100 produces a harder beam spectrum compared to Alloy 1190, it is a reasonable substitute. A combination filter of 0.5 mm copper and 2 mm aluminium produced a spectrum closer to that of Alloy 1190 than Alloy 1100 with the added benefits of lower exposures and lower batch variability. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  16. Human exposure to aluminium.

    PubMed

    Exley, Christopher

    2013-10-01

    Human activities have circumvented the efficient geochemical cycling of aluminium within the lithosphere and therewith opened a door, which was previously only ajar, onto the biotic cycle to instigate and promote the accumulation of aluminium in biota and especially humans. Neither these relatively recent activities nor the entry of aluminium into the living cycle are showing any signs of abating and it is thus now imperative that we understand as fully as possible how humans are exposed to aluminium and the future consequences of a burgeoning exposure and body burden. The aluminium age is upon us and there is now an urgent need to understand how to live safely and effectively with aluminium.

  17. 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.

    PubMed

    Jakobsen, Stig S; Larsen, A; Stoltenberg, M; Bruun, J M; Soballe, K

    2007-09-11

    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.

  18. AE Monitoring of Diamond Turned Rapidly Soldified Aluminium 443

    NASA Astrophysics Data System (ADS)

    Onwuka, G.; Abou-El-Hossein, K.; Mkoko, Z.

    2017-05-01

    The fast replacement of conventional aluminium with rapidly solidified aluminium alloys has become a noticeable trend in the current manufacturing industries involved in the production of optics and optical molding inserts. This is as a result of the improved performance and durability of rapidly solidified aluminium alloys when compared to conventional aluminium. Melt spinning process is vital for manufacturing rapidly solidified aluminium alloys like RSA 905, RSA 6061 and RSA 443 which are common in the industries today. RSA 443 is a newly developed alloy with few research findings and huge research potential. There is no available literature focused on monitoring the machining of RSA 443 alloys. In this research, Acoustic Emission sensing technique was applied to monitor the single point diamond turning of RSA 443 on an ultrahigh precision lathe machine. The machining process was carried out after careful selection of feed, speed and depths of cut. The monitoring process was achieved with a high sampling data acquisition system using different tools while concurrent measurement of the surface roughness and tool wear were initiated after covering a total feed distance of 13km. An increasing trend of raw AE spikes and peak to peak signal were observed with an increase in the surface roughness and tool wear values. Hence, acoustic emission sensing technique proves to be an effective monitoring method for the machining of RSA 443 alloy.

  19. Experimental investigations on mechanical behavior of aluminium metal matrix composites

    NASA Astrophysics Data System (ADS)

    Rajesh, A. M.; Kaleemulla, Mohammed

    2016-09-01

    Today we are widely using aluminium based metal matrix composite for structural, aerospace, marine and automobile applications for its light weight, high strength and low production cost. The purpose of designing metal matrix composite is to add the desirable attributes of metals and ceramics to the base metal. In this study we developed aluminium metal matrix hybrid composite by reinforced Aluminium7075 alloy with silicon carbide (SiC) and aluminium oxide (alumina) by method of stir casting. This technique is less expensive and very effective. The Hardness test and Wear test were performed on the specimens which are prepared by stir casting techniques. The result reveals that the addition of silicon carbide and alumina particles in aluminium matrix improves the mechanical properties.

  20. Recovery of the actinides by electrochemical methods in molten chlorides using solid aluminium cathode

    SciTech Connect

    Malmbeck, R.; Mendes, E.; Serp, J.; Soucek, P.; Glatz, J.P.; Cassayre, L.

    2007-07-01

    An electrorefining process in molten chloride salts is being developed at ITU to reprocess the spent nuclear fuel. According to the thermochemical properties of the system, aluminium is the most promising electrode material for the separation of actinides (An) from lanthanides (Ln). The actinides are selectively reduced from the fission products and stabilized by the formation of solid and compact actinide-aluminium alloys with the reactive cathode material. In this work, the maximum loading of aluminium with actinides was investigated by potentiostatic and galvano-static electrorefining of U-Pu- Zr alloys. A very high aluminium capacity was achieved, as the average loading was 1.6 g of U and Pu into 1 g of aluminium and the maximum achieved loading was 2.3 g. For recovery of the actinides from aluminium, a process based on chlorination and a subsequent sublimation of AlCl{sub 3} is proposed. (authors)

  1. ALUHAB — The Superior Aluminium Foam

    NASA Astrophysics Data System (ADS)

    Babcsan, N.; Beke, S.; Makk, P.; Soki, P.; Számel, Gy; Degischer, H. P.; Mokso, R.

    A new metal foaming technology has been developed to produce aluminum foams with controlled cell sizes, a wide range of alloy compositions, and attractive mechanical properties. ALUHAB aluminium foams are manufactured from a special foamable aluminium alloy containing ultrafine particles (80-3000 nm). The technology uses high temperature ultrasonication to homogeneously disperse the particles and thus create a stable, foamable aluminum melt. Oscillating gas injector (loud-nozzle) technology permits the injection of optimally sized bubbles into the melt that are independent of the injector orifice diameter. Using this direct gas injection method, bubble size is regulated by the frequency and the power of the ultrasound, producing uniform bubble sizes in the sub-millimeter range. The technology results in extremely stable metal foams which can be cast into complex forms and re-melted without loss of foam integrity. Processing methods and properties of the ALUHAB foams will be discussed.

  2. Oxide film on 5052 aluminium alloy: Its structure and removal mechanism by activated CsF-AlF3 flux in brazing

    NASA Astrophysics Data System (ADS)

    Xiao, Bing; Wang, Dongpo; Cheng, Fangjie; Wang, Ying

    2015-05-01

    The oxide-film structure on the 5052 Al alloy and the film-removal mechanism by activated CsF-AlF3 flux in brazing were studied. Characterisation of the oxide film shows that thermally activated Mg, segregated from the alloy's interior, was significantly enriched and oxidised during medium-temperature brazing. Thus, the outer oxide surface consisted of the amorphous MgO-like phase, and the interior of the oxide film comprised mainly the amorphous MgO-like phase and dispersely distributed and less-ordered MgAl2O4. The MgO-like phase was the main obstacle to oxide removal in brazing. The activated ZnCl2-containing CsF-AlF3 flux effectively removed the oxide film, and the 5052 Al alloy was successfully brazed by the Zn-Al filler metal and activated flux. When Zn2+ in the molten flux permeated the oxide film through cracks, its chemical reaction with the Al substrate loosened the oxide film, which was eventually pushed out as the filler metal spread over the alloy surface.

  3. Aluminium radiopacity standards for dentistry: an international survey.

    PubMed

    Watts, D C; McCabe, J F

    1999-01-01

    The aims of this study were to determine the appropriate composition and purity limits of aluminium alloy radiopacity standards for dental biomaterials, taking into account the current status in representative laboratories worldwide, and to formalise the calculation procedure for processing radiopacity data. A series of aluminium step-wedges were obtained from academic and industrial research laboratories. These were analysed by energy dispersive X-ray procedures. The set of step-wedges were independently characterised for radiopacity at two University dental schools. The percentage of aluminium together with the percentages of minor alloying elements (magnesium, manganese, iron and silicon) have been determined as mass percentages. For each centre, the optical density versus step-height for all wedges was judged to fall on a common curve, with the main exception of one step-wedge that was found to contain 4% copper, by mass. A suitable calculation procedure was described explicitly. Of the examined representative step-wedges, all but the aluminium--4% copper material were satisfactory and gave results comparable with wedges of high purity. Limits should therefore be revised for composition of aluminium radiopacity step-wedges or test blocks to a more realistic level of purity. Alloys with more than 0.05% copper or 1.0% iron should be excluded and the aluminium content should be at least 98% by mass. In the calculations deployed for deriving radiopacity as 'equivalent aluminium thicknesses', an appropriate linear regression procedure should be employed and considerable care taken in the evaluation of materials of low or borderline radiopacity, relative to specification limits. The method described is principally suitable for materials with radiopacity greater than 1 mm. For materials with radiopacity less than 1 mm aluminium, thicker specimens (2 mm) should be used.

  4. Electron Conditioning of Technical Aluminium Surfaces: Effect on the Secondary Electron Yield

    SciTech Connect

    Le Pimpec, F.

    2004-12-13

    The effect of electron conditioning on commercially aluminium alloys 1100 and 6063 were investigated. Contrary to the assumption that electron conditioning, if performed long enough, can reduce and stabilize the SEY to low values (< 1.3, value of many pure elements [1] ), the SEY of aluminium did not go lower than 1.8. In fact, it reincreases with continued electron exposure dose.

  5. Experimental comparison of the MIG, friction stir welding, cold metal transfer and hybrid laser-MIG processes for AA 6005-T6 aluminium alloy

    NASA Astrophysics Data System (ADS)

    Caruso, Serafino; Sgambitterra, Emanuele; Rinaldi, Sergio; Gallone, Antonello; Viscido, Lucio; Filice, Luigino; Umbrello, Domenico

    2016-10-01

    In this study, the mechanical properties of welded joints of AA 6005-T6 aluminum alloy obtained with hybrid laser-MIG and cold metal transfer (CMT) welding were analyzed. The performance of hybrid laser-MIG and CMT welded joints were identified using tensile, bending, shear and fatigue life tests. Taking into account the process conditions and requirements, hybrid laser-MIG and CMT welding processes were compared with friction stir welding (FSW) and conventional metal inert gas (MIG) welding processes, shown in a previous work, to understand the advantages and disadvantages of the processes for welding applications of studied Al alloy. Better tensile, bending and shear strength and fatigue life behavior were obtained with hybrid laser-MIG and FSW welded joints compared with conventional MIG processes.

  6. The effect of MAO processing time on surface properties and low temperature infrared emissivity of ceramic coating on aluminium 6061 alloy

    NASA Astrophysics Data System (ADS)

    Al Bosta, Mohannad M. S.; Ma, Keng-Jeng; Chien, Hsi-Hsin

    2013-09-01

    MAO ceramic coatings were prepared on aluminium 6061 surfaces at different treating durations (10, 20, ... 60 min), using alkali silicate electrolyte and pulsed bipolar current mode. The surface microstructures and properties were studied using SEM, XRD, EDX and a surface roughness tester. Image-Pro Plus and MATCH! softwares were used to analyze SEM micrographs and XRD results, respectively. The infrared emissivities of the ceramic coatings were measured at the 70 °C using FTIR spectrometer. We found a linear correlation between the volcano-like area and the surface roughness. The compositions and phases were associated with the volcano-like population and area. The curve of IR spectral emissivity was influenced by surface roughness, γ-alumina, sillimanite and cristobalite phases. The emissivity was enhanced by the surface roughness in the ranges 4.0-9.6 μm and 10.5-14.8 μm. In the range 7.0-8.0 μm, α-alumina and sillimanite phases enhanced the emissivity, while the cristobalite has a negative impact to the emissivity. A negative contributions were found for α-alumina in the region 9.6-16.0 μm and for the surface thickness in the region 15.0-16.0 μm. Overall, the average of long wave infrared (LWIR) emissivity ranged from 87.05% to 91.65%.

  7. The effect of thermal cycling on the bond strength of low-fusing porcelain to commercially pure titanium and titanium-aluminium-vanadium alloy.

    PubMed

    Tróia, Manoel G; Henriques, Guilherme E P; Nóbilo, Mauro A A; Mesquita, Marcelo F

    2003-12-01

    Titanium-ceramic restorations are currently used in spite of the pending problem of titanium-ceramic bonding, which has only been partially solved. In addition, some titanium-ceramic systems appear to be susceptible to thermal cycling, which can cause weaker bond strength. The objective of this study was to evaluate the bonding characteristics of titanium porcelain bonded to commercially pure titanium (Ti-Cp) or titanium-aluminum-vanadium (Ti-6Al-4V) alloy as well as the effect of thermal cycling on bond strength. A three-point-flexure-test was used to evaluate the bond strength of titanium porcelain bonded to commercially pure titanium and Ti-6Al-4V alloy according to DIN 13.927. To evaluate the effect of thermal cycling on the samples, half were thermal cycled in temperatures ranging from 4 degrees C (+/-2 degrees C) to 55 degrees C (+/-2 degrees C). Results were compared with palladium-silver (Pd-Ag) alloy bonded to conventional porcelain (control). Scanning electron microscope (SEM) photomicrographs were taken to characterize the failed surfaces in the metal-ceramic interface. Anova and Tukey's multiple comparison tests were used to analyze the data at a 5% probability level. Thermal cycling did not significantly weaken the bond strength of porcelain to titanium interfaces. There was no significant difference in bond strength between commercially pure titanium (23.60 MPa for thermal cycled group and 24.99 MPa for non-thermal cycled group) and Ti-6Al-4V groups (24.98 and 25.60 MPa for thermal cycled and non-thermal cycled groups, respectively). Bond strength values for the control group (47.98 and 45.30 MPa, respectively) were significantly greater than those for commercially pure titanium and Ti-6Al-4V combinations. The bond strength of low fusing porcelain bonded to cast pure titanium or Ti-6Al-4V alloy was significantly lower than the conventional combination of porcelain-Pd-Ag alloy. Thermal cycling did not affect the bond strength of any group.

  8. Diamond grooving of rapidly solidified optical aluminium

    NASA Astrophysics Data System (ADS)

    Abou-El-Hossein, Khaled; Hsu, Wei-Yao; Ghobashy, Sameh; Cheng, Yuan-Chieh; Mkoko, Zwelinzima

    2015-10-01

    Traditional optical aluminium grades such as Al 6061 are intensively used for making optical components for applications ranging from mould insert fabrication to laser machine making. However, because of their irregular microstructure and relative inhomogeneity of material properties at micro scale, traditional optical aluminium may exhibit some difficulties when ultra-high precision diamond turned. Inhomogeneity and micro-variation in the material properties combined with uneven and coarse microstructure may cause unacceptable surface finish and accelerated tool wear, especially in grooving operation when the diamond tool edge is fully immersed in the material surface. Recently, new grades of optical aluminium that are featured by their ultra-fine microstructure and improved material properties have been developed to overcome the problem of high tool wear rates. The new aluminium grades have been developed using rapid solidification process which results in extremely small grain sizes combined with improved mechanical properties. The current study is concerned with investigating the performance of single-point diamond turning when grooving two grades of rapidly solidified aluminium (RSA) grades: RSA905 which is a high-alloyed aluminium grade and RSA443 which has a high silicon content. In this study, two series of experiments employed to create radial microgrooves on the two RSA grades. The surface roughness obtained on the groove surface is measured when different combinations of cutting parameters are used. Cutting speed is varied while feed rate and depth of cut were kept constant. The results show that groove surface roughness produced on RSA443 is higher than that obtained on RSA905. Also, the paper reports on the effect of cutting speed on surface roughness for each RSA grade.

  9. Volatilisation and oxidation of aluminium scraps fed into incineration furnaces

    SciTech Connect

    Biganzoli, Laura; Gorla, Leopoldo; Nessi, Simone; Grosso, Mario

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Aluminium packaging partitioning in MSW incineration residues is evaluated. Black-Right-Pointing-Pointer The amount of aluminium packaging recoverable from the bottom ashes is evaluated. Black-Right-Pointing-Pointer Aluminium packaging oxidation rate in the residues of MSW incineration is evaluated. Black-Right-Pointing-Pointer 80% of aluminium cans, 51% of trays and 27% of foils can be recovered from bottom ashes. - Abstract: Ferrous and non-ferrous metal scraps are increasingly recovered from municipal solid waste incineration bottom ash and used in the production of secondary steel and aluminium. However, during the incineration process, metal scraps contained in the waste undergo volatilisation and oxidation processes, which determine a loss of their recoverable mass. The present paper evaluates the behaviour of different types of aluminium packaging materials in a full-scale waste to energy plant during standard operation. Their partitioning and oxidation level in the residues of the incineration process are evaluated, together with the amount of potentially recoverable aluminium. About 80% of post-consumer cans, 51% of trays and 27% of foils can be recovered through an advanced treatment of bottom ash combined with a melting process in the saline furnace for the production of secondary aluminium. The residual amount of aluminium concentrates in the fly ash or in the fine fraction of the bottom ash and its recovery is virtually impossible using the current eddy current separation technology. The average oxidation levels of the aluminium in the residues of the incineration process is equal to 9.2% for cans, 17.4% for trays and 58.8% for foils. The differences between the tested packaging materials are related to their thickness, mechanical strength and to the alloy.

  10. On the effect of silicon and phosphorus during the precipitation of kappa-carbide in Iron-Manganese-Aluminium-Carbon alloys

    NASA Astrophysics Data System (ADS)

    Bartlett, Laura Nicole

    Implementation of lightweight high manganese and aluminum steels for use in high energy absorbing applications requires a detailed knowledge of how alloying additions and impurities affect age hardening and high strain rate fracture properties. Dynamic fracture toughness is an important design criterion but has not been reported previously in these alloys. In addition, previous studies have shown that silicon and phosphorus increased the strength and aged hardness; however, the mechanism was unknown. This research mainly focuses on the effect of silicon and phosphorus on the precipitation of kappa-carbide and alloy partitioning during aging. Short range ordering, SRO, of Fe-Al-C into relative atomic positions described by the E21 superlattice structure preceded and occurred concurrent to spinodal decomposition. Short range diffusion of phosphorus increased the kinetics of ordering resulting in a decrease in the time required for subsequent spinodal decomposition and an increase the amplitude of carbon concentration with time. Silicon increased the strength and hardness as a result of increased carbon partitioning into the kappa-carbide during aging. Dynamic fracture toughness was found to depend upon aluminum and carbon. Increasing the amount of solid solution carbon increased the dynamic fracture toughness in solution treated specimens. However, increasing carbon in aged specimens increased the amount of kappa-carbide and produced brittle fracture. Additions of aluminum from three to nine weight percent decreased toughness regardless of the heat treatment. Dynamic fracture toughness was a strong function of AlN content. A good combination of high strength and dynamic toughness with a corresponding density reduction of 10 to 12% is obtained with aluminum additions between 6 and 7% and carbon below 1.2%.

  11. Aluminium toxicity during regular haemodialysis.

    PubMed

    Elliott, H L; Dryburgh, F; Fell, G S; Sabet, S; Macdougall, A I

    1978-04-29

    In the west of Scotland the incidence of dialysis encephalopathy has been confined to three geographical areas where the concentration of aluminium in the water supply is greatly increased owing to the addition of aluminium sulphate. Eight patients with encephalopathy who dialysed at home in these areas had greatly increased serum aluminium concentrations, and a significant correlation was found between serum aluminium concentrations and the concentrations of aluminium in the water supply. This study provides further evidence that the dialysis encephalopathy syndrome is due to aluminium intoxication, the major source of aluminium being the water supply from which dialysis fluid prepared.

  12. Aluminium toxicity during regular haemodialysis.

    PubMed Central

    Elliott, H L; Dryburgh, F; Fell, G S; Sabet, S; Macdougall, A I

    1978-01-01

    In the west of Scotland the incidence of dialysis encephalopathy has been confined to three geographical areas where the concentration of aluminium in the water supply is greatly increased owing to the addition of aluminium sulphate. Eight patients with encephalopathy who dialysed at home in these areas had greatly increased serum aluminium concentrations, and a significant correlation was found between serum aluminium concentrations and the concentrations of aluminium in the water supply. This study provides further evidence that the dialysis encephalopathy syndrome is due to aluminium intoxication, the major source of aluminium being the water supply from which dialysis fluid prepared. PMID:638617

  13. The effect orientation of features in reconstructed atom probe data on the resolution and measured composition of T1 plates in an A2198 aluminium alloy.

    PubMed

    Mullin, Maria A; Araullo-Peters, Vicente J; Gault, Baptiste; Cairney, Julie M

    2015-12-01

    Artefacts in atom probe tomography can impact the compositional analysis of microstructure in atom probe studies. To determine the integrity of information obtained, it is essential to understand how the positioning of features influences compositional analysis. By investigating the influence of feature orientation within atom probe data on measured composition in microstructural features within an AA2198 Al alloy, this study shows differences in the composition of T1 (Al2CuLi) plates that indicates imperfections in atom probe reconstructions. The data fits a model of an exponentially-modified Gaussian that scales with the difference in evaporation field between solutes and matrix. This information provides a guide for obtaining the most accurate information possible.

  14. Processing silicon, silumin and aluminium from feldspars -- A method to regulate the Si, AlSi alloys and Al amounts by a continuous way

    SciTech Connect

    Stubergh, J.R.

    1996-10-01

    Feldspars are mixed with cryolite and electrolyzed at about 1,000 C. In the first bath silicon metal is deposited in a high purity state and in a desired chosen amount. A carbon cathode is placed at the top of the bath and the carbon anode in the bottom of the bath. By the electrolysis CO{sub 2} is formed at the anode and bubbles through the bath in contact with the silicon crystals. In the second bath the rest of Si(IV) in the electrolyte and the rest of the deposited silicon metal from the first bath is then thermally reduced by aluminum metal at the same temperature. Silicon is deposited in aluminum metal as silumin alloys which is removed from the bottom of the bath. In the third bath the Si(IV)-poor electrolyte is electrolyzed by using aluminum metal as a cathode. The Al metal is deposited in the bottom of the bath.

  15. Launcher Roadmap for the CrVI Substitution of Surface Treatments. Screening of Trivalent-Chromium Conversion Solutions and First Promising Results for Repair Applications on Aluminium Alloys

    NASA Astrophysics Data System (ADS)

    Debout, Vincent; Pettier, Sophie

    2014-06-01

    Airbus Defence and Space, Space System is involved in a global roadmap for launchers in order to substitute hexavalent chromium (CrVI) and Cadmium in the current surface treatments on metallic structures.Within this framework, a screening of trivalent chromium (CrIII) conversion solutions for touch-up applications has been carried out since this step is crucial to perform local application or to repair minor damages on launcher structures but it leads to higher risks of exposure for the workers.Three commercial CrIII conversion solutions have been evaluated on high performance aluminum alloys such as AA2024 T3 and AA7175 T7351 that are often used as structural materials.This preliminary investigation highlights the effect of surface preparation, rinsing and conversion process on the final corrosion performance of conversion coatings (CCs). The results are also discussed in terms of visual aspect and adhesion with new Cr-free primers.Two operating sets of parameters are identified with promising results that represent the first steps towards the development of a new Cr-free touch-up process.

  16. Corrosion protection of Al alloys and Al-based metal-matrix composites by chemical passivation

    SciTech Connect

    Mansfeld, F.; Lin, S.; Sim, S.; Shih, H.

    1989-08-01

    Chemical passivation by immersion of aluminium alloys and aluminium 6061/ silicon carbide and aluminium 6061/graphite metal-matrix composites in cerium chloride solution produces very corrosion-resistant surfaces. Aluminium 6061 and aluminium 7075-T6 that had been immersed in 1000 ppm cerium chloride for one week did not suffer from pitting corrosion during immersion in acerated 0.5 N NaCl for three weeks. For aluminium 7075-T7l3 some improvement of the corrosion resistance was also achieved, but to a much lesser extent. Chemical passivation in cerium chloride was also successful for aluminium/silicon carbide and Allgraphite.

  17. Study on aluminium-based single films.

    PubMed

    Vinod Kumar, G S; García-Moreno, F; Babcsán, N; Brothers, A H; Murty, B S; Banhart, J

    2007-12-28

    In the present paper the authors studied isolated metallic films made from the same material used for making metallic foams, and then characterised their properties. Metal films were made from a liquid aluminium alloy reinforced with ceramic particles of known concentration. Melts without such particles were also investigated. It is shown that stable films could not be made from Al-Si alloy having no particles, and just extremely thin and fragile films could be made from commercially-pure Al. In contrast, aluminium alloys containing particles such as SiC and TiB(2) allowed pulling thin, stable films, which did not rupture. Significant thinning of films was observed when the particle concentration in the melt decreased. By in situ X-ray monitoring of liquid films during pulling, film thickness and drainage effects within the liquid film could be studied. The morphology and microstructure of films was characterised after solidification. Our work shows that the question of how foams are stabilised can be studied using a simplified system such as a film, instead of having to deal with the multitude of different structural elements present in a foam.

  18. Buckling tests of aluminium columns at elevated temperatures

    SciTech Connect

    Langhelle, N.K.; Amdahl, J.; Eberg, E.; Lundberg, S.

    1996-12-31

    Accidental fires are events with severe catastrophe potential for all offshore structures, and in particular for aluminium structures. Due to aluminium`s rapid strength degradation at elevated temperatures, this is particular true for aluminium structures. Accurate prediction of fire resistance is therefore essential. Experimental tests are needed to evaluate current design rules and state-of-the-art material models for aluminium under elevated temperatures. An experimental investigation was undertaken in order to study the behavior of AA 6082 alloy aluminium columns at elevated temperatures. Some of the tests were carried out at constant load with increasing temperature. Other tests experienced constant temperature and increasing load. Buckling tests at ambient temperature were also conducted. Particular emphasis was put on high temperature creep effects. The purpose of the tests was to provide data for verification of the material model implemented in the computer program USFOS, for analysis of progressive collapse analyses of space frame structures. The performance of the tempers T4 and T6 as well as columns with transversal welds are compared internally as well as to column buckling curves given in current design codes.

  19. Volatilisation and oxidation of aluminium scraps fed into incineration furnaces.

    PubMed

    Biganzoli, Laura; Gorla, Leopoldo; Nessi, Simone; Grosso, Mario

    2012-12-01

    Ferrous and non-ferrous metal scraps are increasingly recovered from municipal solid waste incineration bottom ash and used in the production of secondary steel and aluminium. However, during the incineration process, metal scraps contained in the waste undergo volatilisation and oxidation processes, which determine a loss of their recoverable mass. The present paper evaluates the behaviour of different types of aluminium packaging materials in a full-scale waste to energy plant during standard operation. Their partitioning and oxidation level in the residues of the incineration process are evaluated, together with the amount of potentially recoverable aluminium. About 80% of post-consumer cans, 51% of trays and 27% of foils can be recovered through an advanced treatment of bottom ash combined with a melting process in the saline furnace for the production of secondary aluminium. The residual amount of aluminium concentrates in the fly ash or in the fine fraction of the bottom ash and its recovery is virtually impossible using the current eddy current separation technology. The average oxidation levels of the aluminium in the residues of the incineration process is equal to 9.2% for cans, 17.4% for trays and 58.8% for foils. The differences between the tested packaging materials are related to their thickness, mechanical strength and to the alloy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Fatal aluminium phosphide poisoning

    PubMed Central

    Mittal, Sachin; Rani, Yashoda

    2015-01-01

    Aluminium phosphide (AlP) is a cheap solid fumigant and a highly toxic pesticide which is commonly used for grain preservation. AlP has currently aroused interest with a rising number of cases in the past four decades due to increased use for agricultural and non-agricultural purposes. Its easy availability in the markets has increased also its misuse for committing suicide. Phosphine inhibits cellular oxygen utilization and can induce lipid peroxidation. Poisoning with AlP has often occurred in attempts to commit suicide, and that more often in adults than in teenagers. This is a case of suicidal consumption of aluminium phosphide by a 32-year-old young medical anesthetist. Toxicological analyses detected aluminium phosphide. We believe that free access of celphos tablets in grain markets should be prohibited by law. PMID:27486362

  1. Tribological properties of aluminium-based materials

    NASA Astrophysics Data System (ADS)

    Iglesias Victoria, Patricia

    In order to improve the tribological performance of the aluminium-steel contact, two research lines have been followed: (1) Use of the ordered fluids liquid crystals and ionic liquids as lubricant additives. (2) Tribological behaviour of new powder metallurgy aluminium materials processed by mechanical milling. A parafinic-naftenic base oil modified by a 1wt% of four additives has been used: Three liquid crystals with increasing polarity: 4,4' -dibutylazobenzene (LC1) < colesteryl linoleate (LC2) < n-dodecyl ammonium chloride (LC3), and the ionic liquid 1-ethyl, 3-methyl-imidazolonium tetrafluoroborate. This is the first time that a ionic liquid is studied as lubricant additive. Viscosity measurements at 25 and 100°C, maximum number of molecules by unit aluminium surface and comparative costs of the additives showed the advantage of the ionic additives over the neutral ones. Pin-on-disk tests were performed according to ASTM G99. Influence of load, speed and temperature on friction and wear was studied for each additive. While the ionic liquid gives low friction (<0.1) and wear (≤10-5 mm3m-1), the performance of the liquid crystalline additives depends on the conditions. LC3 shows a higher lubricating ability than the neutral LC1 and LC2 under high load, speed or temperature. Only the ionic liquid shows tribochemical interaction (by SEM and EDS) with the steel and aluminium surfaces, with an increment in the fluorine content inside the wear track. The second line was to study the influence of the process conditions on the dry and lubricated wear of new powder-metallurgy aluminium materials. MA Al-NH3 milled under NH3 atmosphere was compared with (MA Al-Air) processed in air and with Al-1 which has not been mechanically alloyed. Conditions for mild to severe wear transition have been established. Al-1 is always under a severe wear regime. MA Al-NH3 shows transition to severe wear at 150°C, showing a 60% reduction in wear rate with respect to MA Al-Air and a two

  2. Time-resolved aluminium laser-induced plasma temperature measurements

    NASA Astrophysics Data System (ADS)

    Surmick, D. M.; Parigger, C. G.

    2014-11-01

    We seek to characterize the temperature decay of laser-induced plasma near the surface of an aluminium target from laser-induced breakdown spectroscopy measurements of aluminium alloy sample. Laser-induced plasma are initiated by tightly focussing 1064 nm, nanosecond pulsed Nd:YAG laser radiation. Temperatures are inferred from aluminium monoxide spectra viewed at systematically varied time delays by comparing experimental spectra to theoretical calculations with a Nelder Mead algorithm. The temperatures are found to decay from 5173 ± 270 to 3862 ± 46 Kelvin from 10 to 100 μs time delays following optical breakdown. The temperature profile along the plasma height is also inferred from spatially resolved spectral measurements and the electron number density is inferred from Stark broadened Hβ spectra.

  3. Interfacial morphology of low-voltage anodic aluminium oxide

    SciTech Connect

    Hu, Naiping; Dongcinn, Xuecheng; He, Xueying; Argekar, Sandip; Zhang, Yan; Browning, Jim; Schaefer, Dale

    2013-01-01

    X-ray reflectivity (XRR) and neutron reflectivity (NR), as well as ultra-smallangle X-ray scattering (USAXS), are used to examine the in-plane and surfacenormal structure of anodic films formed on aluminium alloy AA2024 and pure aluminium. Aluminium and alloy films up to 3500 A thick were deposited on Si wafers by electron beam evaporation of ingots. Porous anodic aluminium oxide (AAO) films are formed by polarizing at constant voltage up to 20 V noble to the open circuit potential. The voltage sweet spot (5 V) appropriate for constant-voltage anodization of such thin films was determined for both alloy and pure Al. In addition, a new concurrent voltage- and current-control protocol was developed to prepare films with larger pores (voltages higher than 5 V), but formed at a controlled current so that pore growth is slow enough to avoid stripping the aluminium substrate layer. USAXS shows that the pore size and interpore spacing are fixed in the first 10 s after initiation of anodization. Pores then grow linearly in time, at constant radius and interpore spacing. Using a combination of XRR and NR, the film density and degree of hydration of the films were determined from the ratio of scattering length densities. Assuming a chemical formula Al2O3xH2O, it was found that x varies from 0.29 for the native oxide to 1.29 for AAO grown at 20 V under concurrent voltage and current control. The average AAO film density of the porous film at the air surface is 2.45 (20) g cm3. The density of the barrier layer at the metal interface is 2.9 (4) g cm3, which indicates that this layer is also quite porous

  4. Corrosion of Aluminium Alloys by IRFNA

    DTIC Science & Technology

    1991-09-01

    250C). GA6 was electropolished and anodised. The electropolishing solution was a mixture of Na2CO3 (150g/dm- 3 ) and Na3PO4 (50g/dm-3 ) in deionised...established more rapidly. 2.2.6 Electropolished and Anodised Cell (GA6) Cell GA6 was electropolished in a Na2CO3/ Na3PO4 mixture (14V, 6Adm-2 , 800C

  5. Improved Durability Aluminium Alloys for Airframe Structures

    DTIC Science & Technology

    2000-04-01

    propagation. ,° " Sensitivity to IGC itself is a purely electrochemical C phenomenon (see e.g.1 ,2) determined by the existence of a " , microgalvanic...which is discussed later. S , Beside this main aspect of fatigue, it is necessary to assess the fatigue resistance of the bulk material1 1. Improved...Warner (1994) International patent Kc(MPa4m)* application WO 96/12829. T-L 100 / 150 90 / 130 8 Warner, T J ; Shahani, R A ; Lassince, P ; Raynaud , G M

  6. Fracture and Fatigue Behaviour of Aluminium Matrix Composite Automotive Pistons

    NASA Astrophysics Data System (ADS)

    García-Romero, Ane M.; Egizabal, Pedro; Irisarri, Angel M.

    2010-02-01

    The fracture and fatigue behaviour of prototype automotive pistons produced in an aluminium alloy matrix composite in industrial conditions has been studied. Fracture toughness increased when the testing temperature rose from 20° to 75°C and kept near constant up to 250°C, when a significantly lower value was recorded. A change in the failure operating mechanism, which can explain this trend, was observed by analysing the fracture surfaces in the scanning electron microscope. Room temperature fatigue tests performed with R = 0.1 stress ratio led to an average value of the Paris law exponent higher than those reported in aluminium alloys but low for an industrially produced brittle composite. A higher exponent and a much larger scattering were observed in those fatigue tests carried out under R = 0.5 stress ratio.

  7. Aluminium and human breast diseases.

    PubMed

    Darbre, P D; Pugazhendhi, D; Mannello, F

    2011-11-01

    The human breast is exposed to aluminium from many sources including diet and personal care products, but dermal application of aluminium-based antiperspirant salts provides a local long-term source of exposure. Recent measurements have shown that aluminium is present in both tissue and fat of the human breast but at levels which vary both between breasts and between tissue samples from the same breast. We have recently found increased levels of aluminium in noninvasively collected nipple aspirate fluids taken from breast cancer patients (mean 268 ± 28 μg/l) compared with control healthy subjects (mean 131 ± 10 μg/l) providing evidence of raised aluminium levels in the breast microenvironment when cancer is present. The measurement of higher levels of aluminium in type I human breast cyst fluids (median 150 μg/l) compared with human serum (median 6 μg/l) or human milk (median 25 μg/l) warrants further investigation into any possible role of aluminium in development of this benign breast disease. Emerging evidence for aluminium in several breast structures now requires biomarkers of aluminium action in order to ascertain whether the presence of aluminium has any biological impact. To this end, we report raised levels of proteins that modulate iron homeostasis (ferritin, transferrin) in parallel with raised aluminium in nipple aspirate fluids in vivo, and we report overexpression of mRNA for several S100 calcium binding proteins following long-term exposure of MCF-7 human breast cancer cells in vitro to aluminium chlorhydrate. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Hydrogenated vacancies lock dislocations in aluminium

    SciTech Connect

    Xie, Degang; Li, Suzhi; Li, Meng; Wang, Zhangjie; Gumbsch, Peter; Sun, Jun; Ma, Evan; Li, Ju; Shan, Zhiwei

    2016-11-03

    Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ~103 s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strong locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. In conclusion, vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment.

  9. Hydrogenated vacancies lock dislocations in aluminium

    DOE PAGES

    Xie, Degang; Li, Suzhi; Li, Meng; ...

    2016-11-03

    Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ~103 s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strongmore » locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. In conclusion, vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment.« less

  10. Hydrogenated vacancies lock dislocations in aluminium

    NASA Astrophysics Data System (ADS)

    Xie, Degang; Li, Suzhi; Li, Meng; Wang, Zhangjie; Gumbsch, Peter; Sun, Jun; Ma, Evan; Li, Ju; Shan, Zhiwei

    2016-11-01

    Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ~103 s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strong locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. Vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment.

  11. Hydrogenated vacancies lock dislocations in aluminium

    PubMed Central

    Xie, Degang; Li, Suzhi; Li, Meng; Wang, Zhangjie; Gumbsch, Peter; Sun, Jun; Ma, Evan; Li, Ju; Shan, Zhiwei

    2016-01-01

    Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ∼103 s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strong locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. Vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment. PMID:27808099

  12. Aluminium, antiperspirants and breast cancer.

    PubMed

    Darbre, P D

    2005-09-01

    Aluminium salts are used as the active antiperspirant agent in underarm cosmetics, but the effects of widespread, long term and increasing use remain unknown, especially in relation to the breast, which is a local area of application. Clinical studies showing a disproportionately high incidence of breast cancer in the upper outer quadrant of the breast together with reports of genomic instability in outer quadrants of the breast provide supporting evidence for a role for locally applied cosmetic chemicals in the development of breast cancer. Aluminium is known to have a genotoxic profile, capable of causing both DNA alterations and epigenetic effects, and this would be consistent with a potential role in breast cancer if such effects occurred in breast cells. Oestrogen is a well established influence in breast cancer and its action, dependent on intracellular receptors which function as ligand-activated zinc finger transcription factors, suggests one possible point of interference from aluminium. Results reported here demonstrate that aluminium in the form of aluminium chloride or aluminium chlorhydrate can interfere with the function of oestrogen receptors of MCF7 human breast cancer cells both in terms of ligand binding and in terms of oestrogen-regulated reporter gene expression. This adds aluminium to the increasing list of metals capable of interfering with oestrogen action and termed metalloestrogens. Further studies are now needed to identify the molecular basis of this action, the longer term effects of aluminium exposure and whether aluminium can cause aberrations to other signalling pathways in breast cells. Given the wide exposure of the human population to antiperspirants, it will be important to establish dermal absorption in the local area of the breast and whether long term low level absorption could play a role in the increasing incidence of breast cancer.

  13. Reactive ion beam figuring of optical aluminium surfaces

    NASA Astrophysics Data System (ADS)

    Bauer, Jens; Frost, Frank; Arnold, Thomas

    2017-03-01

    Ultra-smooth and arbitrarily shaped reflective optics are necessary for further progress in EUV/XUV lithography, x-ray and synchrotron technology. As one of the most important technological mirror optic materials, aluminium behaves in a rather difficult way in ultra-precision machining with such standard techniques as diamond-turning and subsequent ion beam figuring (IBF). In particular, in the latter, a strong surface roughening is obtained. Hence, up to now it has not been possible to attain the surface qualities required for UV or just visible spectral range applications. To overcome the limitations mainly caused by the aluminium alloy structural and compositional conditions, a reactive ion beam machining process using oxygen process gas is evaluated. To clarify the principle differences in the effect of oxygen gas contrary to oxygen ions on aluminium surface machining, we firstly focus on chemical-assisted ion beam etching (CAIBE) and reactive ion beam etching (RIBE) experiments in a phenomenological manner. Then, the optimum process route will be explored within a more quantitative analysis applying the concept of power spectral density (PSD) for a sophisticated treatment of the surface topography. Eventually, the surface composition is examined by means of dynamic secondary ion mass spectrometry (SIMS) suggesting a characteristic model scheme for the chemical modification of the aluminium surface during oxygen ion beam machining. Monte Carlo simulations were applied to achieve a more detailed process conception.

  14. A 3D printed superconducting aluminium microwave cavity

    SciTech Connect

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Tobar, Michael E.; Sercombe, Timothy B.

    2016-07-18

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  15. A 3D printed superconducting aluminium microwave cavity

    NASA Astrophysics Data System (ADS)

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Sercombe, Timothy B.; Tobar, Michael E.

    2016-07-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  16. The toxicity of aluminium in humans.

    PubMed

    Exley, C

    2016-06-01

    We are living in the 'aluminium age'. Human exposure to aluminium is inevitable and, perhaps, inestimable. Aluminium's free metal cation, Alaq(3+), is highly biologically reactive and biologically available aluminium is non-essential and essentially toxic. Biologically reactive aluminium is present throughout the human body and while, rarely, it can be acutely toxic, much less is understood about chronic aluminium intoxication. Herein the question is asked as to how to diagnose aluminium toxicity in an individual. While there are as yet, no unequivocal answers to this problem, there are procedures to follow to ascertain the nature of human exposure to aluminium. It is also important to recognise critical factors in exposure regimes and specifically that not all forms of aluminium are toxicologically equivalent and not all routes of exposure are equivalent in their delivery of aluminium to target sites. To ascertain if Alzheimer's disease is a symptom of chronic aluminium intoxication over decades or breast cancer is aggravated by the topical application of an aluminium salt or if autism could result from an immune cascade initiated by an aluminium adjuvant requires that each of these is considered independently and in the light of the most up to date scientific evidence. The aluminium age has taught us that there are no inevitabilities where chronic aluminium toxicity is concerned though there are clear possibilities and these require proving or discounting but not simply ignored. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Aluminium Involvement in Neurotoxicity

    PubMed Central

    Fulgenzi, Alessandro; Vietti, Daniele; Ferrero, Maria Elena

    2014-01-01

    The aetiology of neurodegenerative diseases (ND) seems to involve susceptibility genes and environmental factors. Toxic metals are considered major environmental pollutants. Following our study of a case of multiple sclerosis (MS) improvement due to removal of aluminium (Al) and other toxic metals, we have examined the possible relationship between Al intoxication and ND. We used the slow intravenous treatment with the chelating agent EDTA (calcium disodium ethylene diamine tetraacetic acid) (chelation test) to remove Al and detected it in the urine collected from the patients for 12 hours. Patients affected by MS represented 85.6% of total ND. Al was present in 44.8% of cases comprehensive of ND and healthy patients. Al levels were significantly higher in ND patients than in healthy subjects. We here show that treatment of patients affected by Al burden with ten EDTA chelation therapies (EDTA intravenous administration once a week) was able to significantly reduce Al intoxication. PMID:25243176

  18. Dependence in Classification of Aluminium Waste

    NASA Astrophysics Data System (ADS)

    Resti, Y.

    2015-06-01

    Based on the dependence between edge and colour intensity of aluminium waste image, the aim of this paper is to classify the aluminium waste into three types; pure aluminium, not pure aluminium type-1 (mixed iron/lead) and not pure aluminium type 2 (unrecycle). Principal Component Analysis (PCA) was employed to reduction the dimension of image data, while Bayes’ theorem with the Gaussian copula was applied to classification. The copula was employed to handle dependence between edge and colour intensity of aluminium waste image. The results showed that the classifier has been correctly classifiable by 88.33%.

  19. Aluminium surface treatment with ceramic phases using diode laser

    NASA Astrophysics Data System (ADS)

    Labisz, K.; Tański, T.; Brytan, Z.; Pakieła, W.; Wiśniowski, M.

    2016-07-01

    Ceramic particles powder feeding into surface layer of engineering metal alloy is a well-known and widely used technique. New approach into the topic is to obtain finely distributed nano-sized particles involved in the aluminium matrix using the traditional laser technology. In this paper are presented results of microstructure investigation of cast aluminium-silicon-copper alloys surface layer after heat treatment and alloying with ceramic carbides of WC and ZrO2 using high-power diode laser. The surface layer was specially prepared for the reason of reducing the reflectivity, which is the main problem in the up-to-date metal matrix composites production. With scanning electron microscopy, it was possible to determine the deformation process and distribution of WC and ZrO2 ceramic powder phase. Structure of the surface after laser treatment changes, revealing three zones—remelting zone, heat-affected zone and transition zone placed over the Al substrate. The structural changes of ceramic powder, its distribution and morphology as well as microstructure of the matrix material influence on functional properties, especially wear resistance and hardness of the achieved layer, were investigated.

  20. Consolidation of copper and aluminium powders by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Saiprasad, M.; Atchayakumar, R.; Thiruppathi, K.; Raghuraman, S.

    2016-09-01

    Processing in the powder metallurgy route has emerged as an economical process for the production of near net shaped components with a wide range of desired mechanical properties suitable for various applications of industrial needs. This research work was conducted with an objective of studying the improvisation of density and hardness of Copper-Aluminium alloy prepared by spark plasma sintering. Cu-Al alloy with a composition of 95% copper and 5% aluminium was prepared by SPS process. SPS is a low voltage, DC pulse current activated, pressure-assisted sintering, which enables sintering at lower temperatures and shorter durations. The combination offered by Cu-Al alloy of high strength and high corrosion resistance results their applications under a wide variety of conditions. The density and hardness of the prepared sample were measured by conducting appropriate tests. Apparently, the values of hardness and density of the specimen prepared by SPS seemed to be better than that of conventional sintering. The experimental procedure, testing methodologies and analysis are presented.

  1. Special issue on aluminium plasmonics

    DOE PAGES

    Gerard, Davy; Gray, Stephen K.

    2015-04-08

    Plasmonics is a rapidly growing field that takes advantage of the intense and confined electromagnetic fields that appear near metallic nanostructures illuminated at frequencies near their surface plasmon resonances. As plasmonics continues to develop, it faces the need to find new materials supporting well-defined surface plasmon resonances in different frequency ranges. In the visible and near-infrared ranges the noble metals, most typically gold and silver, exhibit relatively low losses. This is why they are quite ubiquitous in plasmonics literature. However it is somewhat ironic to see that a non-noble metal, aluminium, the metal upon which surface plasmons where first evidencedmore » in the 1950s, is now reappearing after fifty years of near oblivion as one of the 'hottest' materials for plasmonics. Several reasons explain the return of aluminium to the centre stage. First, aluminium exhibits good plasmonic properties in the ultraviolet and deep ultraviolet—a spectral range where gold and silver no longer behave as metals. Second, aluminium is cheap and widely available (Al is the third most abundant element in the earth's crust), criteria of paramount importance when discussing industry-related applications. It is furthermore compatible with complementary metal–oxide–semiconductor (CMOS) technology. In conclusion, this is why an ever-increasing number of papers report new advances on aluminium plasmonics.« less

  2. Special issue on aluminium plasmonics

    SciTech Connect

    Gerard, Davy; Gray, Stephen K.

    2015-04-08

    Plasmonics is a rapidly growing field that takes advantage of the intense and confined electromagnetic fields that appear near metallic nanostructures illuminated at frequencies near their surface plasmon resonances. As plasmonics continues to develop, it faces the need to find new materials supporting well-defined surface plasmon resonances in different frequency ranges. In the visible and near-infrared ranges the noble metals, most typically gold and silver, exhibit relatively low losses. This is why they are quite ubiquitous in plasmonics literature. However it is somewhat ironic to see that a non-noble metal, aluminium, the metal upon which surface plasmons where first evidenced in the 1950s, is now reappearing after fifty years of near oblivion as one of the 'hottest' materials for plasmonics. Several reasons explain the return of aluminium to the centre stage. First, aluminium exhibits good plasmonic properties in the ultraviolet and deep ultraviolet—a spectral range where gold and silver no longer behave as metals. Second, aluminium is cheap and widely available (Al is the third most abundant element in the earth's crust), criteria of paramount importance when discussing industry-related applications. It is furthermore compatible with complementary metal–oxide–semiconductor (CMOS) technology. In conclusion, this is why an ever-increasing number of papers report new advances on aluminium plasmonics.

  3. Synergistic effects of carboxymethyl cellulose and ZnO as alkaline electrolyte additives for aluminium anodes with a view towards Al-air batteries

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Wang, Dapeng; Zhang, Daquan; Gao, Lixin; Lin, Tong

    2016-12-01

    The synergistic effects of carboxymethyl cellulose (CMC) and zinc oxide (ZnO) have been investigated as alkaline electrolyte additives for the AA5052 aluminium alloy anode in aluminium-air battery by the hydrogen evolution test, the electrochemical measurements and the surface analysis method. The combination of CMC and ZnO effectively retards the self-corrosion of AA5052 alloy in 4 M NaOH solution. A complex film is formed via the interaction between CMC and Zn2+ ions on the alloy surface. The carboxyl groups adsorbed on the surface of aluminium make the protective film more stable. The cathodic reaction process is mainly suppressed significantly. AA5052 alloy electrode has a good discharge performance in the applied electrolyte containing the composite CMC/ZnO additives.

  4. Comparative study using MS and XRD of Fe80Al20 alloy produced by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Hadef, F.; Otmani, A.; Grenèche, J. M.

    2013-08-01

    An X-ray diffraction and 57Fe Mössbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe(Al) solid solution was formed after 2 h of milling, while the analysis of Mössbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to: (i) rapid nanocrystallization of aluminium and/or (ii) small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.

  5. Aluminium phosphide-induced leukopenia

    PubMed Central

    Ntelios, Dimitrios; Mandros, Charalampos; Potolidis, Evangelos; Fanourgiakis, Panagiotis

    2013-01-01

    Acute intoxication from the pesticide aluminium phosphide is a relatively rare, life-threatening condition in which cardiovascular decompensation is the most feared problem. We report the case of a patient exposed to aluminium phosphide-liberated phosphine gas. It resulted in the development of a gastroenteritis-like syndrome accompanied by severe reduction in white blood cell numbers as an early and prominent manifestation. By affecting important physiological processes such as mitochondrial function and reactive oxygen species homeostasis, phosphine could cause severe toxicity. After presenting the characteristics of certain leucocyte subpopulations we provide the current molecular understanding of the observed leukopenia which in part seems paradoxical. PMID:24172776

  6. High Temperature Mass Spectrometry of Liquid Nickel-Aluminum Alloys at 2000 K

    DTIC Science & Technology

    1991-05-01

    cmporatlire range 1200 K to 1400 K. Malkin and Pokidyshev 1151 used electromotive force (emf) measurements on a high temperature galvanic cell with a molten...relation. Schaeffer [16] used emf measurements on a high temperature galvanic cell with a molten salt electrolyte to calculate aluminium activities of...measurements on a high temperature galvanic cell with a solid electrolyte to calculate aluminium activities of solid nickel-rich alloys with aluminium

  7. Role of ultrasonic treatment, inoculation and solute in the grain refinement of commercial purity aluminium.

    PubMed

    Wang, G; Wang, Q; Easton, M A; Dargusch, M S; Qian, M; Eskin, D G; StJohn, D H

    2017-08-29

    The present study investigates the influence of ultrasonic treatment on the grain refinement of commercial purity aluminium with a range of Al3Ti1B master alloy additions. When the aluminium contains the smallest amount of added master alloy, ultrasonics caused significant additional grain refinement compared to that provided by the master alloy alone. However, the influence of ultrasonics on grain size reduces with increasing addition of the master alloy which adds additional TiB2 particles and Ti solute with each incremental addition. Applying the Interdependence model to analyse the experimentally measured grain sizes revealed that the results of this study and those from similar experiments on an Al-2Cu alloy were consistent when the alloy compositions are converted to their growth restriction factors (Q) and that increasing Q had a major effect on reducing grain size and increasing grain number density. Compared with the application of ultrasonic treatment where an order of magnitude increase in the grain number density is achieved, an increase in the Ti content over the range of master alloy additions, causes the grain number density to increase by approximately three times.

  8. The prophylactic reduction of aluminium intake.

    PubMed

    Lione, A

    1983-02-01

    The use of modern analytical methods has demonstrated that aluminium salts can be absorbed from the gut and concentrated in various human tissues, including bone, the parathyroids and brain. The neurotoxicity of aluminium has been extensively characterized in rabbits and cats, and high concentrations of aluminium have been detected in the brain tissue of patients with Alzheimer's disease. Various reports have suggested that high aluminium intakes may be harmful to some patients with bone disease or renal impairment. Fatal aluminium-induced neuropathies have been reported in patients on renal dialysis. Since there are no demonstrable consequences of aluminium deprivation, the prophylactic reduction of aluminium intake by many patients would appear prudent. In this report, the major sources of aluminium in foods and non-prescription drugs are summarized and alternative products are described. The most common foods that contain substantial amounts of aluminium-containing additives include some processed cheeses, baking powders, cake mixes, frozen doughs, pancake mixes, self-raising flours and pickled vegetables. The aluminium-containing non-prescription drugs include some antacids, buffered aspirins, antidiarrhoeal products, douches and haemorrhoidal medications. The advisability of recommending a low aluminium diet for geriatric patients is discussed in detail.

  9. Occupational asthma caused by aluminium welding.

    PubMed

    Vandenplas, O; Delwiche, J P; Vanbilsen, M L; Joly, J; Roosels, D

    1998-05-01

    Work-related asthma has been documented in workers employed in the primary aluminium industry and in the production of aluminium salts. The role of aluminium in the development of occupational asthma has, however, never been convincingly substantiated. We investigated a subject who experienced asthmatic reactions related to manual metal arc welding on aluminium. Challenge exposure to aluminium welding with flux-coated electrodes, as well as with electrodes without flux, elicited marked asthmatic reactions. Manual metal arc welding on mild steel did not cause significant bronchial response. The results of inhalation challenges combined with exposure assessments provided evidence that aluminium can cause asthmatic reactions in the absence of fluorides. Awareness of this possibility may be relevant to the investigation of asthma in workers exposed to aluminium.

  10. Aluminium toxicity in chronic renal insufficiency

    SciTech Connect

    Savory, J.; Bertholf, R.L.; Wills, M.R.

    1985-08-01

    Aluminium is a ubiquitous element in the environment and has been demonstrated to be toxic, especially in individuals with impaired renal function. Not much is known about the biochemistry of aluminium and the mechanisms of its toxic effects. Most of the interest in aluminium has been in the clinical setting of the hemodialysis unit. Here aluminium toxicity occurs due to contamination of dialysis solutions, and treatment of the patients with aluminium-containing phosphate binding gels. Aluminium has been shown to be the major contributor to the dialysis encephalopathy syndrome and an osteomalacic component of dialysis osteodystrophy. Other clinical disturbances associated with aluminium toxicity are a microcytic anemia and metastatic extraskeletal calcification. Aluminium overload can be treated effectively by chelation therapy with desferrioxamine and hemodialysis. Aluminium is readily transferred from the dialysate to the patient's -bloodstream during hemodialysis. Once transferred, the aluminium is tightly bound to non-dialysable plasma constituents. Very low concentrations of dialysate aluminium in the range of 10-15 micrograms/l are recommended to guard against toxic effects. Very few studies have been directed towards the separation of the various plasma species which bind eluminium. Gel filtration chromatography has been used to identify five major fractions, one of which is of low molecular weight and the others appear to be protein-aluminium complexes. Recommendations on aluminium monitoring have been published and provide safe and toxic concentrations. Also, the frequency of monitoring has been addressed. Major problems exist with the analytical methods for measuring aluminium which result from inaccurate techniques and contamination difficulties. 136 references.

  11. Corrosion of dental aluminium bronze in neutral saline and saline lactic acid.

    PubMed

    Tibballs, J E; Erimescu, Raluca

    2006-09-01

    To compare the corrosion behaviours of two aluminium bronze, dental casting alloys during a standard immersion test and for immersion in neutral saline. Cast specimens of aluminium bronzes with 1.4 wt% Fe (G) and 4 wt% Fe (N) were subject to progressively longer periods (up to in total 7 days) immersed in 0.1 M saline, 0.1 M lactic acid solutions and examined by scanning electron microscopy with EDX analysis. Immersion in 0.1M neutral saline was for 7 days. In the acidic solution, exposed interdendritic volumes in alloy N corroded completely away in 7 days with dissolution of Ni-enriched precipitate species as well as the copper-rich matrix. Alloy G begins to corrode more slowly but by a similar mechanism. The number density of an Fe-enriched species is insufficient to maintain a continuous galvanic potential to the copper matrix, and dissolution becomes imperceptible. In neutral saline solution, galvanic action alone caused pit-etching, without the dissolution of either precipitate species. The upper limit for the total dissolution of metallic ions in the standard immersion test can be set at 200 microg cm(-2). Aluminium bronze dental alloys can be expected to release both copper and nickel ions into an acidic oral environment.

  12. Downscaled anodic oxidation process for aluminium in oxalic acid

    NASA Astrophysics Data System (ADS)

    Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A.; Lampke, T.

    2017-03-01

    The increasing multi-functionality of parts and assemblies in several fields of engineering demands, amongst others, highly functionalised surfaces. For the different applications, on the one hand, there is a need to scale up surface modification processes originating in the nano- and micro-scale. On the other hand, conventional macro-scale surface refinement methods offer a huge potential for application in the said nano- and micro-scale. The anodic oxidation process, which is established especially for aluminium and its alloys, allows the formation of oxide ceramic layers on the surface. The build-up of an oxide ceramic coating comes along with altered chemical, tribological and electrical surface properties. As a basis for further investigations regarding the use of the anodic oxidation process for micro-scale-manufacturing, the scale effects of oxalic acid anodising on commercially pure aluminium as well as on the AlZn5.5MgCu alloy are addressed in the present work. The focus is on the amount of oxide formed during a potentiostatic process in relation to the exchanged amount of charge. Further, the hardness of the coating as an integral measure to assess the porous oxide structure is approached by nano-indentation technique.

  13. Experimental study of friction in aluminium bolted joints

    NASA Astrophysics Data System (ADS)

    Croccolo, D.; de Agostinis, M.; Vincenzi, N.

    2010-06-01

    This study aims at developing an experimental tool useful to define accurately the friction coefficients in bolted joints and, therefore, at relating precisely the tightening torque to the bolt preloading force in some special components used in front motorbike suspensions. The components under investigation are some clamped joints made of aluminium alloy. The preloading force is achieved by applying a torque wrench to the bolt head. Some specific specimens have been appropriately designed and realized in order to study the tribological aspects of the tightening phase. Experimental tests have been performed by applying the Design of Experiment (DOE) method in order to obtain a mathematical model for the friction coefficients. Three replicas of a full factorial DOE at two levels for each variable have been carried out. The levels include cast versus forged aluminium alloy, anodized versus spray-painted surface, lubricated versus unlubricated screw, and first tightening (fresh unspoiled surfaces) versus sixth tightening (spoiled surfaces). The study considers M8x1.25 8.8 galvanized screws.

  14. Bumblebee Pupae Contain High Levels of Aluminium

    PubMed Central

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer’s disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline. PMID:26042788

  15. Bumblebee pupae contain high levels of aluminium.

    PubMed

    Exley, Christopher; Rotheray, Ellen; Goulson, David

    2015-01-01

    The causes of declines in bees and other pollinators remains an on-going debate. While recent attention has focussed upon pesticides, other environmental pollutants have largely been ignored. Aluminium is the most significant environmental contaminant of recent times and we speculated that it could be a factor in pollinator decline. Herein we have measured the content of aluminium in bumblebee pupae taken from naturally foraging colonies in the UK. Individual pupae were acid-digested in a microwave oven and their aluminium content determined using transversely heated graphite furnace atomic absorption spectrometry. Pupae were heavily contaminated with aluminium giving values between 13.4 and 193.4 μg/g dry wt. and a mean (SD) value of 51.0 (33.0) μg/g dry wt. for the 72 pupae tested. Mean aluminium content was shown to be a significant negative predictor of average pupal weight in colonies. While no other statistically significant relationships were found relating aluminium to bee or colony health, the actual content of aluminium in pupae are extremely high and demonstrate significant exposure to aluminium. Bees rely heavily on cognitive function and aluminium is a known neurotoxin with links, for example, to Alzheimer's disease in humans. The significant contamination of bumblebee pupae by aluminium raises the intriguing spectre of cognitive dysfunction playing a role in their population decline.

  16. Aluminium content of Spanish infant formula.

    PubMed

    Navarro-Blasco, I; Alvarez-Galindo, J I

    2003-05-01

    Levels of aluminium in 82 different infant formulae from nine different manufacturers in Spain were determined by acid-microwave digestion and graphite furnace atomic absorption spectrophotometry. The influence of aluminium content in tap water in reconstituted powder formulae was examined and an estimate was made of the theoretical toxic aluminium intake in comparison with the provisional tolerable weekly intake (PTWI). Possible interactions between aluminium and certain essential trace elements added to infant formulations have been studied according to the type or main protein-based infant formula. In general, the infant formulae contained a higher aluminium content than that found in human milk, especially in the case of soya, preterm or hydrolysed casein-based formulae. Standard formulae gave lower aluminium intakes amounting to about 4% PTWI. Specialized and preterm formulae resulted in a moderate intake (11-12 and 8-10% PTWI, respectively) and soya formulae contributed the highest intake (15% PTWI). Aluminium exposure from drinking water used for powder formula reconstitution was not considered a potential risk. In accordance with the present state of knowledge about aluminium toxicity, it seems prudent to call for continued efforts to standardize routine quality control and reduce aluminium levels in infant formula as well as to keep the aluminium concentration under 300 microg l(-1) for all infant formulae, most specifically those formulae for premature and low birth neonates.

  17. The study of aluminium anodes for high power density Al/air batteries with brine electrolytes

    NASA Astrophysics Data System (ADS)

    Nestoridi, Maria; Pletcher, Derek; Wood, Robert J. K.; Wang, Shuncai; Jones, Richard L.; Stokes, Keith R.; Wilcock, Ian

    Aluminium alloys containing small additions of both tin (∼0.1 wt%) and gallium (∼0.05 wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2 A cm -2 can be obtained at potentials close to the open circuit potential, ∼-1500 mV versus SCE. The tin exists in the alloys as a second phase, typically as ∼1 μm inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated.

  18. Localised anodic oxidation of aluminium material using a continuous electrolyte jet

    NASA Astrophysics Data System (ADS)

    Kuhn, D.; Martin, A.; Eckart, C.; Sieber, M.; Morgenstern, R.; Hackert-Oschätzchen, M.; Lampke, T.; Schubert, A.

    2017-03-01

    Anodic oxidation of aluminium and its alloys is often used as protection against material wearout and corrosion. Therefore, anodic oxidation of aluminium is applied to produce functional oxide layers. The structure and properties of the oxide layers can be influenced by various factors. These factors include for example the properties of the substrate material, like alloy elements and heat treatment or process parameters, like operating temperature, electric parameters or the type of the used electrolyte. In order to avoid damage to the work-piece surface caused by covering materials in masking applications, to minimize the use of resources and to modify the surface in a targeted manner, the anodic oxidation has to be localised to partial areas. Within this study a proper alternative without preparing the substrate by a mask is investigated for generating locally limited anodic oxidation by using a continuous electrolyte jet. Therefore aluminium material EN AW 7075 is machined by applying a continuous electrolyte jet of oxalic acid. Experiments were carried out by varying process parameters like voltage or processing time. The realised oxide spots on the aluminium surface were investigated by optical microscopy, SEM and EDX line scanning. Furthermore, the dependencies of the oxide layer properties from the process parameters are shown.

  19. Application of in situ thermography for evaluating the high-cycle and very high-cycle fatigue behaviour of cast aluminium alloy AlSi7Mg (T6).

    PubMed

    Krewerth, D; Weidner, A; Biermann, H

    2013-12-01

    The present paper illustrates the application of infrared thermal measurements for the investigation of crack initiation point and crack propagation in the high-cycle and the very high-cycle fatigue range of cast AlSi7Mg alloy (A356). The influence of casting defects, their location, size and amount was studied both by fractography and thermography. Besides internal and surface fatigue crack initiation as a further crack initiation type multiple fatigue crack initiation was observed via in situ thermography which can be well correlated with the results from fractography obtained by SEM investigations. In addition, crack propagation was studied by the development of the temperature measured via thermography. Moreover, the frequency influence on high-cycle fatigue behaviour was investigated. The presented results demonstrate well that the combination of fractography and thermography can give a significant contribution to the knowledge of crack initiation and propagation in the VHCF regime. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Tensile and fatigue behaviour of self-piercing rivets of CFRP to aluminium for automotive application

    NASA Astrophysics Data System (ADS)

    Kang, J.; Rao, H.; Zhang, R.; Avery, K.; Su, X.

    2016-07-01

    In this study, the tensile and fatigue behaviour of self-piercing rivets (SPRs) in carbon fibre reinforced plastic (CFRP) to aluminium 6111 T82 alloys were evaluated. An average maximum lap-shear tensile load capacity of 3858 N was achieved, which is comparable to metal-to-metal SPR lap-shear joints. The CFRP-Al SPRs failed in lap-shear tension due to pull-out of the rivet head from the CFRP upper sheet. The CFRP-Al SPR lap- shear specimens exhibited superior fatigue life compared to previously studied aluminium-to- aluminium SPR lap-shear joints. The SPR lap-shear joints under fatigue loads failed predominantly due to kinked crack growth along the width of the bottom aluminium sheet. The fatigue cracks initiated in the plastically deformed region of the aluminium sheet close to the rivet shank in the rivet-sheet interlock region. Scatter in fatigue life and failure modes was observed in SPR lap-shear specimens tested close to maximum tensile load.

  1. Nano-crystalline P/M aluminium for automotive applications

    NASA Astrophysics Data System (ADS)

    Hummert, K.; Schattevoy, R.; Broda, M.; Knappe, M.; Beiss, P.; Klubberg, F.; Schubert, T. H.; Leuschner, R.

    2009-01-01

    The reduction of total vehicle weight and lowering of moving masses within the engine are key elements to overcome future emission challenges of the automotive industry. Within a German BMBF funded project the melt spinning technology will be driven to a series production status. The very fast cooling condition of the melt leads to a nano-structure of the aluminium material. This results in new material properties of known alloys. The strength increases dramatically without lowered forming behaviour. With this process the freedom of designing complex alloys is very flexible. Different alloys have been investigated for several applications, where high strength at room and elevated temperatures and/or high wear resistance is required. This paper presents some results regarding the processing, microstructure and mechanical properties of a developed Al-Ni-Fe alloy. This joined research project with partners from the automotive industry as well as automotive suppliers and universities is funded by the German BMBF "NanoMobile" Program under Project number 03X3008.

  2. A review of semi-solid aluminium-steel joining processes

    NASA Astrophysics Data System (ADS)

    Obeidi, Muhannad; McCarthy, Éanna; Brabazon, Dermot

    2016-10-01

    The semi-solid metal (SSM) forming process can be applied to achieve near net shape forming of metal alloys, and provides superior component properties compared to those achievable with conventional casting methods. The technique, also commonly called thixoforming, relies on achieving a spheroidal microstructure within the metal alloy so that its fluidity can be adjusted to achieve a controlled laminar filling of the die. Despite the better quality and the higher mechanical properties of an SSM product, thixoforming still represents only 1% of the total aluminium production, which can be explained by the higher premium cost of the processing equipment compared to conventional die casting. The method has also proven successful as a joining method, for joining similar and dissimilar materials. This paper reviews semisolid forming as a forming method and as a joining method, in particular the joining of dissimilar materials such as stainless steel to aluminium.

  3. Aluminium in foodstuffs and diets in Sweden.

    PubMed

    Jorhem, L; Haegglund, G

    1992-01-01

    The levels of aluminium have been determined in a number of individual foodstuffs on the Swedish market and in 24 h duplicate diets collected by women living in the Stockholm area. The results show that the levels in most foods are very low and that the level in vegetables can vary by a factor 10. Beverages from aluminium cans were found to have aluminium levels not markedly different from those in glass bottles. Based on the results of the analysis of individual foods, the average Swedish daily diet was calculated to contain about 0.6 mg aluminium, whereas the mean content of the collected duplicate diets was 13 mg. A cake made from a mix containing aluminium phosphate in the baking soda was identified as the most important contributor of aluminium to the duplicate diets. Tea and aluminium utensils were estimated to increase the aluminium content of the diets by approximately 4 and 2 mg/day, respectively. The results also indicate that a considerable amount of aluminium must be introduced from other sources.

  4. Enriched alloy layer on an Al-Cu alloy studied by cyclic voltammetry

    NASA Astrophysics Data System (ADS)

    García Vergara, S. J.; Blanco Pinzon, C. E.; Skeldon, P.

    2017-01-01

    The behaviour of enriched Al-0.7at.%Cu alloy is investigated using cyclic voltammetry. Enriched alloy layers at the interface between the alloy/oxide film were developed by alkaline etching at 5mAcm-2 in 0.1M sodium hydroxide solution at 298K, with the time of etching determining the extent of enrichment. Cyclic voltammograms were recorded at a scan rate of 10mV s-1 in naturally aerated 0.1M ammonium pentaborate solution at 298K. The current overshoot of the enriched alloys was different from that for non-enriched alloy. The latter material revealed the usual single peaks, which are very similar. In contrast, the overshoot comprised two or more components for the enriched alloys. The behaviour is suggested to be associated with the atomic bonding of aluminium in copper-rich and aluminium-rich regions of the enriched alloy layer, with influence on the activation potentials for oxidation of aluminium.

  5. Effect of the layer of anodized 7075-T6 aluminium corrosion properties

    NASA Astrophysics Data System (ADS)

    Montoya Z, R. D.; L, E. Vera; Pineda T, Y.; Cedeño, M. L.

    2017-01-01

    Aluminium alloys are widely used in various sectors of industry. The 7075-T6 alloy corresponding to an Al-Zn T6, is mostly used as structural component in the aviation industry, due to the good relationship between weight and mechanical properties. However, the negative point of this alloys is the resistance to corrosion, which is why they need to be coated with an anodic film. Different surface treatments, such as anodizing, are used to improve corrosion resistance. Anodizing is an electrolytic process by which a protective layer on aluminium known as “alumina” is formed, this is formed by the passage of an electric current in an acidic electrolyte. This investigation presents a study of the effect of the thickness of layers of alumina deposited by anodized method, in the corrosion resistance of 7075-T6 aluminium. This study was performed by using in a solution of tartaric acid - sulfuric acid and an inorganic salt. To evaluate the influence alumina layer thickness on the corrosion properties some tests were carried out by using the electrochemical spectroscopy impedances (EIS) technique and Tafel polarization curves. It was found that the grown of the thickness of film favourably influences in the corrosion resistance.

  6. Aluminium Pneumoconiosis I. In Vitro Comparison of Stamped Aluminium Powders Containing Different Lubricating Agents and a Granular Aluminium Powder

    PubMed Central

    Corrin, B.

    1963-01-01

    The discrepancy in previous reports of the action of aluminium on the lung may be explained by differences between stamped and granular aluminium powders. A stamped powder of the variety causing pulmonary fibrosis showed a brisk reaction with water, but a granular powder was unreactive. This difference is primarily due to the granular particles being covered by inert aluminium oxide, the formation of which is partially prevented in the stamping process by stearine and mineral oil. The reactivity of the flake-like stamped particles is also dependent on their large surface area per unit volume. The appearance of aluminium pneumoconiosis in Britain is explained by the introduction of mineral oil into the stamping industry for, in contrast to stearine, mineral oil permits the powder to react with water. The lung damage is believed to be caused by a soluble form of aluminium. PMID:14072616

  7. A Study on 3-Body Abrasive Wear Behaviour of Aluminium 8011 / Graphite Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Latha Shankar, B.; Anil, K. C.; Patil, Rahul

    2016-09-01

    Metals and alloys have found their vital role in many applications like structural, corrosive, tribological, etc., in engineering environment. The alloys/composites having high strength to low weight ratio have gained attention of many researchers recently. In this work, graphite reinforced Aluminium 8011 metal matrix composite was prepared by conventional stir casting route, by varying the weight % of reinforcement. Uniform distribution of Graphite in matrix alloy was confirmed by optical micrographs. Prepared composite specimens were subjected to 3-body abrasive testing by varying applied load and time, the silica particles of 400 grit size were used as abrasive particles. It was observed that with the increase of weight% of Graphite the wear resistance of composite was also increasing and on comparison it was found that reinforced composite gives good wear resistance than base alloy.

  8. New metallic alloys incorporating fullerenes and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Doome, R. J.; Fonseca, A.; Nagy, J. B.

    1998-08-01

    In order to open new routes to fullerenes application, we have investigated the effect of fullerenes and nanotubes in metallic alloys. Fullerenes mixture and carbon nanotubes have been used as new carbon sources in the synthesis of metallic alloys (Al, Fe and Ni). After melting under inert atmosphere, macroscopic homogeneous alloys were obtained with iron and nickel but the aluminium based alloys looked rather inhomogeneous due to an incomplete melting. From the samples analysis by chemical reactions and XPS, it was concluded that the carbon is essentially located on the alloy surface as carbide and sp2 structures. Except for the aluminium based alloy where some fullerenes were still detected, thermal treatment as well as metal catalytic effect led to the decomposition of the fullerenes in the alloys. Nevertheless, carbon nanotubes kept their structure and were trapped in the alloys. The hardness of these new alloys were determined and compared to values of common alloys incorporating graphite and norit-A as carbon sources. The preliminary results showed slightly higher hardness values for alloys incorporating fullerenes and weaker values for alloys incorporating carbon nanotubes.

  9. Lactobacillus plantarum CCFM639 alleviates aluminium toxicity.

    PubMed

    Yu, Leilei; Zhai, Qixiao; Liu, Xiaoming; Wang, Gang; Zhang, Qiuxiang; Zhao, Jianxin; Narbad, Arjan; Zhang, Hao; Tian, Fengwei; Chen, Wei

    2016-02-01

    Aluminium (Al) is the most abundant metal in the earth's crust. Al exposure can cause a variety of adverse physiological effects in humans and animals. Our aim was to demonstrate that specific probiotic bacteria can play a special physiologically functional role in protection against Al toxicity in mice. Thirty strains of lactic acid bacteria (LAB) were tested for their aluminium-binding ability, aluminium tolerance, their antioxidative capacity, and their ability to survive the exposure to artificial gastrointestinal (GI) juices. Lactobacillus plantarum CCFM639 was selected for animal experiments because of its excellent performance in vitro. Forty mice were divided into four groups: control, Al only, Al plus CCFM639, and Al plus deferiprone (DFP). CCFM639 was administered at 10(9) CFU once daily for 10 days, followed by a single oral dose of aluminium chloride hexahydrate at 5.14 mg aluminium (LD50) for each mouse. The results showed that CCFM639 treatment led to a significant reduction in the mortality rates with corresponding decrease in intestinal aluminium absorption and in accumulation of aluminium in the tissues and amelioration of hepatic histopathological damage. This probiotic treatment also resulted in alleviation of hepatic, renal, and cerebral oxidative stress. The treatment of L. plantarum CCFM639 has potential as a therapeutic dietary strategy against acute aluminium toxicity.

  10. High aluminium content of infant milk formulas.

    PubMed Central

    Weintraub, R; Hams, G; Meerkin, M; Rosenberg, A R

    1986-01-01

    The aluminium content of several commercially available infant milk formulas was measured by electrothermal atomic absorption spectrometry. Results were compared with those for fresh breast milk, cow's milk, and local tap water. Differences in aluminium concentration of greater than 150-fold were found, with the lowest concentrations in breast milk. PMID:3767424

  11. Chelometric determination of aluminium in vaccines*

    PubMed Central

    Meijerman, G. W.; van Lier, K. L.

    1965-01-01

    A rapid and accurate chelometric method is described for the determination of aluminium in aluminium-phosphate-adsorbed vaccines. Thiomersal preservative in the vaccine is first destroyed and the aluminium content is determined by addition of excess disodium edetate (Na2-EDTA) and back-titration with zinc sulfate using dithizone as an indicator. Phosphate does not interfere with the method. The aluminium content of the samples under investigation varied from 0.3 mg/ml to 1.0 mg/ml. In analysis of vaccines containing inactivated poliomyelitis virus, aluminium was determined with a standard deviation of 0.0014 mg and in other vaccines with a standard deviation of approximately 0.0040 mg. PMID:5294262

  12. Aluminium Diphosphamethanides: Hidden Frustrated Lewis Pairs.

    PubMed

    Styra, Steffen; Radius, Michael; Moos, Eric; Bihlmeier, Angela; Breher, Frank

    2016-07-04

    The synthesis and characterisation of two aluminium diphosphamethanide complexes, [Al(tBu)2 {κ(2) P,P'-Mes*PCHPMes*}] (3) and [Al(C6 F5 )2 {κ(2) P,P'-Mes*PCHPMes*}] (4), and the silylated analogue, Mes*PCHP(SiMe3 )Mes* (5), are reported. The aluminium complexes feature four-membered PCPAl core structures consisting of diphosphaallyl ligands. The silylated phosphine 5 was found to be a valuable precursor for the synthesis of 4 as it cleanly reacts with the diaryl aluminium chloride [(C6 F5 )2 AlCl]2 . The aluminium complex 3 reacts with molecular dihydrogen at room temperature under formation of the acyclic σ(2) λ(3) ,σ(3) λ(3) -diphosphine Mes*PCHP(H)Mes* and the corresponding dialkyl aluminium hydride [tBu2 AlH]3 . Thus, 3 belongs to the family of so-called hidden frustrated Lewis pairs.

  13. Biological indicators of exposure to total and respirable aluminium dust fractions in a primary aluminium smelter.

    PubMed Central

    Röllin, H B; Theodorou, P; Cantrell, A C

    1996-01-01

    OBJECTIVES: The study attempts to define biological indicators of aluminium uptake and excretion in workers exposed to airborne aluminium compounds in a primary aluminium smelter. Also, this study defines the total and respirable aluminium dust fractions in two different potrooms, and correlates their concentrations with biological indicators in this group of workers. METHODS: Air was sampled at defined work sites. Non-destructive and conventional techniques were used to find total and respirable aluminium content of the dust. Blood and urine was collected from 84 volunteers employed at various work stations throughout the smelter and from two different cohorts of controls matched for sex, age, and socioeconomic status. Aluminium in serum samples and urine specimens was measured by flameless atomic absorption with a PE 4100 ZL spectrometer. RESULTS: The correlation of aluminium concentrations in serum and urine samples with the degree of exposure was assessed for three arbitrary exposure categories; low (0.036 mg Al/m3), medium (0.35 mg Al/m3) and high (1.47 mg Al/m3) as found in different areas of the smelter. At medium and high exposure, the ratio of respirable to total aluminium in the dust samples varied significantly. At high exposure, serum aluminium, although significantly raised, was still within the normal range of an unexposed population. The workers with low exposure excreted aluminium in urine at levels significantly higher than the controls, but still within the normal range of the population. However, potroom workers with medium and high exposure had significantly higher urinary aluminium than the normal range. CONCLUSIONS: It is concluded that only urinary aluminium constitutes a practical index of occupational exposure at or above 0.35 mg Al/m3, and that the respirable fraction of the dust may play a major role in the biological response to exposure to aluminium in a smelter environment. PMID:8758038

  14. Intestinal absorption of aluminium in renal failure.

    PubMed

    Drüeke, Tilman B

    2002-01-01

    The proportion of the daily ingested aluminium that is absorbed in the intestinal tract has remained a matter of debate for many years because no reliable method of measurement was available. Studies with earlier analytic techniques reported fractional absorption of aluminium from as little as 0.001% to as much as 27% of an oral dose. Measurement of (26)Al by high-energy accelerator mass spectrometry has permitted more accurate analyses. In normal young rats, 0.05-0.1% of ingested aluminium is absorbed in the intestine, of which roughly half goes to the skeleton within 2 h, whereas the remaining half is excreted in the urine, most of it within 48 h. Deposition in organs other than the skeleton appears to be negligible. In healthy human volunteers, the most recent estimates of fractional intestinal (26)Al absorption were also in the range of 0.06-0.1%. In both rats and humans, intestinal absorption of aluminium is subject to many systemic and local factors. The latter include various compounds with which aluminium is complexed in the gut lumen, and gastric acidity. The influence of food is controversial; however, absorption appears higher in the fasted than the post-prandial state. Luminal phosphate concentration decreases aluminium absorption, whereas citrate increases it. For theoretical reasons, silicates should prevent aluminium absorption, but experimental evidence has not supported this theory. Whether water hardness affects aluminium bioavailability remains a matter of debate. General conditions may also modify aluminium absorption and deposition in bone. Examples of these general factors include the uraemic syndrome, diabetes mellitus, secondary hyperparathyroidism, vitamin D status, Alzheimer's disease and Down's syndrome. Awareness of intestinal absorption of aluminium is particularly important, given that aluminium-based binders continue to be used in uraemic patients, despite the hazards of aluminium accumulation. The lessons we have learned about

  15. Abrasive wear of alumina fibre-reinforced aluminium

    NASA Astrophysics Data System (ADS)

    Axen, N.; Alahelisten, A.; Jacobson, S.

    1994-04-01

    The friction and abrasive wear behaviour of an Al-Si1MgMn aluminium alloy reinforced with 10, 15 and 30 vol.% of alumina fibers has been evaluated. The influence of fiber content, matrix hardness, applied load as well as the hardness and size of the abrasive grits was investigated. The tests were performed with a pin-on-drum two-body abrasion apparatus. The wear mechanisms were studied using scanning electron microscopy. It is shown that fiber reinforcement increases the wear resistance in milder abrasive situations, i.e. small and soft abrasives and low loads. However, in tougher abrasive situations, meaning coarse and hard abrasives and high loads, the wear resistance of the composites is equal to or, in some cases, even lower than that of the unreinforced material. It is also shown that the coefficient of friction decreases with increasing fiber content and matrix hardness of the composites.

  16. Aluminium segregation of TiAl during single crystal growth

    SciTech Connect

    Bi, Y.J.; Abell, J.S.

    1997-09-15

    {gamma}-TiAl single crystals have been successfully prepared by an induction-heated cold crucible Czochralski technique which offers more flexibility than vertical float zoning. Compositional analysis of the Czochralski grown single crystals indicates a homogeneous composition after initial transition; and the average composition is close to the peritectic composition. However, {gamma}-TiAl single crystals prepared by vertical float zoning show a small aluminium segregation profile along the growth direction; and the average composition of the as-grown crystals is close to that of the starting alloy. Compositional analysis further demonstrated the banded structure with alternative single {gamma}-phase and {alpha}{sub 2} + {gamma} lamellar regions in the vertical float zoned Ti-54 at.% Al.

  17. Alveolar proteinosis associated with aluminium dust inhalation.

    PubMed

    Chew, R; Nigam, S; Sivakumaran, P

    2016-08-01

    Secondary alveolar proteinosis is a rare lung disease which may be triggered by a variety of inhaled particles. The diagnosis is made by detection of anti-granulocyte-macrophage colony-stimulating factor antibodies in bronchoalveolar lavage fluid, which appears milky white and contains lamellar bodies. Aluminium has been suggested as a possible cause, but there is little evidence in the literature to support this assertion. We report the case of a 46-year-old former boilermaker and boat builder who developed secondary alveolar proteinosis following sustained heavy aluminium exposure. The presence of aluminium was confirmed both by histological examination and metallurgical analysis of a mediastinal lymph node. Despite cessation of exposure to aluminium and treatment with whole-lung lavage which normally results in improvements in both symptoms and lung function, the outcome was poor and novel therapies are now being used for this patient. It may be that the natural history in aluminium-related alveolar proteinosis is different, with the metal playing a mediating role in the disease process. Our case further supports the link between aluminium and secondary alveolar proteinosis and highlights the need for measures to prevent excessive aluminium inhalation in relevant industries. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Aluminium in Biological Environments: A Computational Approach

    PubMed Central

    Mujika, Jon I; Rezabal, Elixabete; Mercero, Jose M; Ruipérez, Fernando; Costa, Dominique; Ugalde, Jesus M; Lopez, Xabier

    2014-01-01

    The increased availability of aluminium in biological environments, due to human intervention in the last century, raises concerns on the effects that this so far “excluded from biology” metal might have on living organisms. Consequently, the bioinorganic chemistry of aluminium has emerged as a very active field of research. This review will focus on our contributions to this field, based on computational studies that can yield an understanding of the aluminum biochemistry at a molecular level. Aluminium can interact and be stabilized in biological environments by complexing with both low molecular mass chelants and high molecular mass peptides. The speciation of the metal is, nonetheless, dictated by the hydrolytic species dominant in each case and which vary according to the pH condition of the medium. In blood, citrate and serum transferrin are identified as the main low molecular mass and high molecular mass molecules interacting with aluminium. The complexation of aluminium to citrate and the subsequent changes exerted on the deprotonation pathways of its tritable groups will be discussed along with the mechanisms for the intake and release of aluminium in serum transferrin at two pH conditions, physiological neutral and endosomatic acidic. Aluminium can substitute other metals, in particular magnesium, in protein buried sites and trigger conformational disorder and alteration of the protonation states of the protein's sidechains. A detailed account of the interaction of aluminium with proteic sidechains will be given. Finally, it will be described how alumnium can exert oxidative stress by stabilizing superoxide radicals either as mononuclear aluminium or clustered in boehmite. The possibility of promotion of Fenton reaction, and production of hydroxyl radicals will also be discussed. PMID:24757505

  19. Aspects of ultra-high-precision diamond machining of RSA 443 optical aluminium

    NASA Astrophysics Data System (ADS)

    Mkoko, Z.; Abou-El-Hossein, K.

    2015-08-01

    Optical aluminium alloys such as 6061-T6 are traditionally used in ultra-high precision manufacturing for making optical mirrors for aerospace and other applications. However, the optics industry has recently witnessed the development of more advanced optical aluminium grades that are capable of addressing some of the issues encountered when turning with single-point natural monocrystalline diamond cutters. The advent of rapidly solidified aluminium (RSA) grades has generally opened up new possibilities for ultra-high precision manufacturing of optical components. In this study, experiments were conducted with single-point diamond cutters on rapidly solidified aluminium RSA 443 material. The objective of this study is to observe the effects of depth of cut and feed rate at a fixed rotational speed on the tool wear rate and resulting surface roughness of diamond turned specimens. This is done to gain further understanding of the rate of wear on the diamond cutters versus the surface texture generated on the RSA 443 material. The diamond machining experiments yielded machined surfaces which are less reflective but with consistent surface roughness values. Cutting tools were observed for wear through scanning microscopy; relatively low wear pattern was evident on the diamond tool edge. The highest tool wear were obtained at higher depth of cut and increased feed rate.

  20. Process Simulation of Aluminium Sheet Metal Deep Drawing at Elevated Temperatures

    SciTech Connect

    Winklhofer, Johannes; Trattnig, Gernot; Sommitsch, Christof

    2010-06-15

    Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this disadvantage is deep drawing at elevated temperatures. In this way the formability of aluminium sheet metal can be improved significantly, and the number of necessary production steps can thereby be reduced. This paper introduces deep drawing of aluminium sheet metal at elevated temperatures, a corresponding simulation method, a characteristic process and its optimization. The temperature and strain rate dependent material properties of a 5xxx series alloy and their modelling are discussed. A three dimensional thermomechanically coupled finite element deep drawing simulation model and its validation are presented. Based on the validated simulation model an optimised process strategy regarding formability, time and cost is introduced.

  1. Investigation of mechanical properties of aluminium reinforced glass fibre polymer composites

    NASA Astrophysics Data System (ADS)

    Kumar, G. B. Veeresh; Pramod, R.

    2017-07-01

    This paper presents the recent work about reinforcing E-glass into Aluminium foil to attain high strength to weight ratio. Aluminium is corrosion resistant, light in weight and ductile, also when alloyed through other metals deliver the greater strengths as desirable for high-tech applications. The density of pure Aluminium is 2.7 g cm3. Electrical grade glass formally known as E-glass, is by far the most used fiber in reinforced plastic composites. It is a high strength material with light weight compared to steel and corrosive resistant. The matrix and reinforcement is bonded with a resin, named Araldite Ly556, which has density at 25 °C, 1.15-1.20 g cm3. Thus gives a good binding structure. In the present work, Aluminium, E-Glass and Epoxy are combined to fabricate a laminate by Hand-Lay process. Hand-lay is the oldest and simplest method used for producing reinforced plastic laminates. The fabricated metal matrix composites are tested for their mechanical properties. The metal laminate is found to render high strength, hardness, flexural strength and increased wear resistance. Further theoretical simulations was carried out to validate the experimental results.

  2. Process Simulation of Aluminium Sheet Metal Deep Drawing at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Winklhofer, Johannes; Trattnig, Gernot; Lind, Christoph; Sommitsch, Christof; Feuerhuber, Hannes

    2010-06-01

    Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this disadvantage is deep drawing at elevated temperatures. In this way the formability of aluminium sheet metal can be improved significantly, and the number of necessary production steps can thereby be reduced. This paper introduces deep drawing of aluminium sheet metal at elevated temperatures, a corresponding simulation method, a characteristic process and its optimization. The temperature and strain rate dependent material properties of a 5xxx series alloy and their modelling are discussed. A three dimensional thermomechanically coupled finite element deep drawing simulation model and its validation are presented. Based on the validated simulation model an optimised process strategy regarding formability, time and cost is introduced.

  3. Modelling of stress fields during LFEM DC casting of aluminium billets by a meshless method

    NASA Astrophysics Data System (ADS)

    Mavrič, B.; Šarler, B.

    2015-06-01

    Direct Chill (DC) casting of aluminium alloys is a widely established technology for efficient production of aluminium billets and slabs. The procedure is being further improved by the application of Low Frequency Electromagnetic Field (LFEM) in the area of the mold. Novel LFEM DC processing technique affects many different phenomena which occur during solidification, one of them being the stresses and deformations present in the billet. These quantities can have a significant effect on the quality of the cast piece, since they impact porosity, hot-tearing and cold cracking. In this contribution a novel local radial basis function collocation method (LRBFCM) is successfully applied to the problem of stress field calculation during the stationary state of DC casting of aluminium alloys. The formulation of the method is presented in detail, followed by the presentation of the tackled physical problem. The model describes the deformations of linearly elastic, inhomogeneous isotropic solid with a given temperature field. The temperature profile is calculated using the in-house developed heat and mass transfer model. The effects of low frequency EM casting process parameters on the vertical, circumferential and radial stress and on the deformation of billet surface are presented. The application of the LFEM appears to decrease the amplitudes of the tensile stress occurring in the billet.

  4. Usinage des composites a matrice d'alliage d'aluminium GrA-Ni(Reg)

    NASA Astrophysics Data System (ADS)

    Songmene, Victor

    2001-07-01

    Aluminium Metal Matrix Composites (MMC) reinforced with ceramic particles have been increasingly developed during the last decade. Ceramic particles used as reinforcement that improve the wear resistance of composites also cause high abrasive wear on cutting tools. This thesis investigates the machinability of graphitic MMC consisting of an aluminium alloy matrix reinforced with both soft nickel-coated graphite particles and hard (SiC or Al2O 3) particles. These composites were developed seven years ago, but the lack of optimised machining data to machine GrA-NIRTM composites cost effectively have been slowing down their use in engineering applications. Turning, milling and drilling tests were performed to evaluate the machinability of different GrA-NIRTM and to establish cutting conditions. It was found that: (1) The machinability of GrA-NiRTM composites depends on the nature and the percentage of the reinforcing particles. GrA-NiRTM containing alumina and graphite are easier to machine than those reinforced with silicon carbide and graphite. (2) Polycrystalline (PCD) and diamond-coated carbide (DCC) are the tool material of choice for machining GrA-NiRTM. DCC tools are most cost effective while PCD tools produce better part finishes. (3) The cutting force required to machine the GrA-NIRTM composites is similar to that used for aluminium alloys such as Al 380.

  5. Ionic fluids in lubrication of aluminium-steel contacts. Surface and tribochemical interactions

    NASA Astrophysics Data System (ADS)

    Jimenez Ballesta, Ana Eva

    Room-temperature ionic liquids (ILs) are high performance fluids with a wide thermal stability range. They are being studied as new lubricants in a variety of sliding contacts. One of their more interesting tribological applications is that of steel-aluminium lubrication. In this work we study the influence of the lateral alkyl chain length and of the anion on the lubricating ability of six imidazolium ILs, a pyridinium and a phosphonium derivative. For first time, these ILs have been studied as neat lubricants and as 1wt.% base oil additives in variable conditions of velocity, load and temperature in pin-on-disk tests for AISI 52100 steel-ASTM 2011 aluminium contacts. In this work we present the first study of ILs as lubricants under extreme temperature conditions. The tribological performance of ILs has been compared with that of a mineral oil and of a synthetic ester. Under these conditions, ILs show lower friction and wear values than conventional oils at all temperatures. As 1wt.% additives, the conditions of optimum lubrication and the transitions between regimes and lubrication mechanisms have been determined. We have also studied the performance of ILs as 1wt.% additives of the synthetic oil. A relationship between additive polarity and wear index has been established. If the more soluble phosphonium IL additive is used, no friction or wear reduction takes place due to competition between solvation and adsorption processes. Electronic microscopy (SEM), energy dispersive (EDS) and X-ray photoelectron (XPS) spectroscopies have been used to study the wear mechanisms and tribochemical processes that take place in the contact. Finally, we have studied the performance of three aluminium alloys in corrosion and erosion-corrosion tests. In immersion tests with free-water ILs, the aluminium alloy 2011 shows a good resistance to corrosion, but dilution of 1-ethyl, 3-methylimidazolium tetrafluoroborate in water produces the hydrolysis of the anion and the corrosion of

  6. Novel method for joining CFRP to aluminium

    NASA Astrophysics Data System (ADS)

    Möller, F.; Thomy, C.; Vollertsen, F.; Schiebel, P.; Hoffmeister, C.; Herrmann, A. S.

    The current state of the art in joining of carbon-fibre reinforced composites (CFRP) to metals such as aluminium is - for the case of aircraft structures, e.g.- riveting or bolting. However, to reduce structural weight and improve structural performance, integral, load-bearing aluminium-CFRP-structures are desirable. To produce such structures, a novel joint configuration together with an appropriate thermal, laser-based joining process is suggested by the authors. In this paper, the joint configuration (based on CFRP-Ti-aluminium joints) and the laser beam conduction welding process will be presented, and first specimens obtained will be discussed with respect to their properties. It will be shown that the novel approach is in principle suitable to produce load-bearing CFRP-aluminium structures.

  7. The removal of iron from molten aluminium

    SciTech Connect

    Donk, H.M. van der; Nijhof, G.H.; Castelijns, C.A.M.

    1995-12-31

    In this work an overview is given about the techniques available for the removal of metallic impurities from molten aluminium. The overview is focused on the removal of iron. Also, some experimental results are given about the creation of iron-rich intermetallic compounds in an aluminium system, which are subsequently removed by gravity segregation and filtration techniques. This work is part of an ongoing research project of three major European aluminium companies who are co-operating on the subject of recycling of aluminium packaging materials recovered from household waste by means of Eddy-Current techniques. Using this technique the pick-up of some contaminating metals, particularly iron, is almost unavoidable.

  8. Aluminium speciation in effluents and receiving waters.

    PubMed

    Gardner, M J; Comber, S D W

    2003-12-01

    The respective speciation of aluminium in sewage effluent and in river water receiving effluent, has been examined. Results showed that concentrations of reactive aluminium changed over a timescale of hours and were controlled predominantly by pH. A minimum concentration of reactive aluminium occurred at a pH of approximately 6.8, coinciding with the prevalence of non-reactive, insoluble Al(OH)3 species. For receiving waters of low pH value, typically < pH 5, a large proportion of the 'naturally present' aluminium can be present in a reactive form at concentrations higher than the proposed Environmental Quality Standard (EQS). Mixing of waters of this type with effluent of a higher pH value leads to the precipitation of aluminium hydroxide. Mixing of effluent of pH value in the range 7.5-8.0 with river water in the same (or slightly higher) pH range appears to result in no appreciable change in the proportion of reactive aluminium; the change in concentration tends to be related simply to dilution. On the basis of a theoretical knowledge of aluminium speciation, results obtained in this work indicate that it is possible to make predictions about the proportion of reactive aluminium present in a receiving water, based on the pH values of the effluent water mixture and the concentration in the effluent. Reasonable comparisons between measured and predicted values were obtained at higher pH values, but the relationship was less certain at pH values less than 6.5 for which levels of reactive metal tended to be higher than the quality standard value.

  9. A Study on Effect of Graphite Particles on Tensile, Hardness and Machinability of Aluminium 8011 Matrix Material

    NASA Astrophysics Data System (ADS)

    Latha Shankar, B.; Anil, K. C.; Karabasappagol, Prasann J.

    2016-09-01

    Industrial application point of view, metal matrix composites in general and Aluminium alloy matrix composites in particular are ideal candidates because of their favourable engineering properties. Being lightweight Aluminium matrix composites are widely used in aircraft, defence and automotive industries. In this work Aluminium 8011 metal matrix was reinforced with fine Graphite particles of 50 μm. developed by two-step Stir casting method. Graphite weight %was varied in the range 2, 4, 6 and 8%. Uniform dispersion of graphite particle is examined under optical microscope. Tensile test coupons were prepared as per standard to determine % of elongation and tensile strength for various % of graphite particle. Hardness of developed composite for various % of graphite particle and Machinability parameters were also studied for effect on surface finish. It was observed that with increase of weight percentage of Graphite particles up to 8% in Aluminium 8011 alloy matrix there was increase in tensile strength, decrease in % of elongation with increase in hardness. Machinability study revealed that, there was decrease in surface roughness with increase in Graphite content.

  10. Effect of Steel slag on Wear Characterization of Aluminium Composite Using Taguchi Technique

    NASA Astrophysics Data System (ADS)

    Sridhar Raja, K. S.; Bupesh Raja, V. K.; Aaro Rinold, F.; Abhilash, L. S.

    2017-05-01

    A wear behavior of steel slag reinforced aluminium A356 composite was fabricated by stir casting technique. Here an attempt has been made by reinforcing steel slag particle of size (1-5micron) in the aluminium matrix alloy fabricated through stir casting process. Dry sliding wear behavior of the composite was studied by pin on disc method. The experiment was conducted through Taguchi technique. A L16 orthogonal array was developed using ANOVA and the regression analysis was determined to find the optimum parameter. The parameters such as applied load, sliding speed, percentage reinforcement, and the distance travelled are considered for wear test. By considering the’ smaller the best’ the dry sliding wear was analyzed. Based on analysis of variance (ANOVA) the single-to-noise ratio are used to investigate the wear rate parameters. By studying the SEM analysis the worn out parts are studied.

  11. Fabrication of Nano-Composite Surface Layers on Aluminium Employing Friction Stir Processing Technique

    SciTech Connect

    Bozorg, S. F. K.; Zarghani, A. S.; Zarei-Hanzaki, A.

    2010-03-11

    Al/Al{sub 2}O{sub 3} nano-composite surface layer was fabricated via friction stir processing technique. Commercial AA6082 aluminium alloy extruded bar and nanometric Al{sub 2}O{sub 3} powder were subjected to friction stir processing at a substrate travel speed of 80 mm/min and a tool rotation speed of 1000 rpm using a hardened H-13 tool steel. The grain structure and reinforcement particles were investigated by using optical and scanning electron microscopy. Results show that Al{sub 2}O{sub 3} particles can be more uniformly dispread in aluminium substrate by increasing the number of processing passes. Also, hardness enhancement of the nano-composite surface layer was found. This is attributed to uniform dispersion of Al{sub 2}O{sub 3} particles.

  12. Effect of magnesium addition on the wetting of alumina by aluminium

    NASA Astrophysics Data System (ADS)

    Sangghaleh, Ali; Halali, Mohammad

    2009-07-01

    In this report the wetting behaviour between polycrystalline alumina substrates and molten aluminium doped with magnesium as a wetting agent has been studied using the sessile drop technique. The time required for equilibrium attainment is investigated. To explore the formation of possible phases at the interface, electron microscopic studies along with EDX analysis have been employed. It is found that magnesium reduces the time and temperature required for equilibrium in the Al/Al 2O 3 system. The Al-7 wt% Mg and Al-10 wt% Mg alloys can wet alumina at temperatures as low as 900 °C. It is also found that molten aluminium doped with magnesium can wet polycrystalline alumina at temperatures below 1000 °C. A thin reaction layer was observed at the Al-Mg/Al 2O 3 interface in the present study.

  13. [Aluminium content in foods with aluminium-containing food additives].

    PubMed

    Ogimoto, Mami; Suzuki, Kumi; Kabashima, Junichiro; Nakazato, Mitsuo; Uematsu, Yoko

    2012-01-01

    The aluminium (Al) content of 105 samples, including bakery products made with baking powder, agricultural products and seafoods treated with alum, was investigated. The amounts of Al detected were as follows (limit of quantification: 0.01 mg/g): 0.01-0.37 mg/g in 26 of 57 bakery products, 0.22-0.57 mg/g in 3 of 6 powder mixes, 0.01-0.05 mg/g in all three agricultural products examined, 0.03-0.90 mg/g in 4 of 6 seafood samples, 0.01-0.03 mg/g in 3 of 11 samples of instant noodles, 0.04-0.14 mg/g in 3 of 4 samples of vermicelli, 0.01 mg/g in 1 of 16 soybean products, but none in soybeans. Amounts equivalent to the PTWI of a 16 kg infant were detected in two samples of bakery products, two samples of powder mixes and one sample of salted jellyfish, if each sample was taken once a week. These results suggest that certain foods, depending on the product and the intake, might exceed the PTWI of children, especially infants.

  14. Joining of Aluminium Alloy Sheets by Rectangular Mechanical Clinching

    SciTech Connect

    Abe, Y.; Mori, K.; Kato, T.

    2011-05-04

    A mechanical clinching has the advantage of low running costs. However, the joint strength is not high. To improve the maximum load of the joined sheets by a mechanical clinching, square and rectangular mechanical clinching were introduced. In the mechanical clinching, the two sheets are mechanically joined by forming an interlock between the lower and upper sheets by the punch and die. The joined length with the interlock was increased by the rectangular punch and die. The deforming behaviours of the sheets in the mechanical clinching were investigated, and then the interlock in the sheets had distribution in the circumference of the projection. Although the interlocks were formed in both projection side and diagonal, the interlock in the diagonal was smaller because of the long contact length between the lower sheet and the die cavity surface. The maximum load of the joined sheets by the rectangular mechanical clinching was two times larger than the load by the round mechanical clinching.

  15. A Brief Research Review for Improvement Methods the Wettability between Ceramic Reinforcement Particulate and Aluminium Matrix Composites

    NASA Astrophysics Data System (ADS)

    Razzaq, Alaa Mohammed; Majid, Dayang Laila Abang Abdul; Ishak, M. R.; B, Uday M.

    2017-05-01

    The development of new methods for addition fine ceramic powders to Al aluminium alloy melts, which would lead to more uniform distribution and effective incorporation of the reinforcement particles into the aluminium matrix alloy. Recently the materials engineering research has moved to composite materials from monolithic, adapting to the global need for lightweight, low cost, quality, and high performance advanced materials. Among the different methods, stir casting is one of the simplest ways of making aluminium matrix composites. However, it suffers from poor distribution and combination of the reinforcement ceramic particles in the metal matrix. These problems become significantly effect to reduce reinforcement size, more agglomeration and tendency with less wettability for the ceramic particles in the melt process. Many researchers have carried out different studies on the wettability between the metal matrix and dispersion phase, which includes added wettability agents, fluxes, preheating the reinforcement particles, coating the reinforcement particles, and use composting techniques. The enhancement of wettability of ceramic particles by the molten matrix alloy and the reinforcement particles distribution improvement in the solidified matrix is the main objective for many studies that will be discussed in this paper.

  16. Study of Magnetic Alloys: Critical Phenomena.

    DTIC Science & Technology

    MAGNETIC ALLOYS, TRANSPORT PROPERTIES), ELECTRICAL RESISTANCE, SEEBECK EFFECT , MAGNETIC PROPERTIES, ALUMINUM ALLOYS, COBALT ALLOYS, GADOLINIUM ALLOYS, GOLD ALLOYS, IRON ALLOYS, NICKEL ALLOYS, PALLADIUM ALLOYS, PLATINUM ALLOYS, RHODIUM ALLOYS

  17. Analysis of aluminium in rat following administration of allergen immunotherapy using either aluminium or microcrystalline-tyrosine-based adjuvants.

    PubMed

    McDougall, Stuart A; Heath, Matthew D; Kramer, Matthias F; Skinner, Murray A

    2016-03-01

    Investigation into the absorption, distribution and elimination of aluminium in rat after subcutaneous aluminium adjuvant formulation administration using ICP-MS is described. Assays were verified under the principles of a tiered approach. There was no evidence of systemic exposure of aluminium, in brain or in kidney. Extensive and persistent retention of aluminium at the dose site was observed for at least 180 days after administration. This is the first published work that has quantified aluminium adjuvant retention based on the quantity of aluminium delivered in a typical allergy immunotherapy course. The results indicate that the repeated administration of aluminium-containing adjuvants will likely contribute directly and significantly to an individual's body burden of aluminium.

  18. [Aluminium allergy and granulomas induced by vaccinations for children].

    PubMed

    Andersen, Rosa Marie Ø; Zachariae, Claus; Johansen, Jeanne Duus

    2015-04-27

    Vaccination with aluminium-adsorbed vaccines can induce aluminium allergy with persistent itching subcutaneous nodules at the injection site – vaccination granulomas. In this article we give an overview of childhood aluminium-adsorbed vaccines available in Denmark. Through literature studies we examine the incidence, the symptoms and the prognosis for the vaccination granulomas and the allergy. Finally we discuss the status in Denmark.

  19. Aluminium levels in spices and aromatic herbs.

    PubMed

    López, F F; Cabrera, C; Lorenzo, M L; López, M C

    2000-08-10

    We evaluated the levels of aluminium in a total of 72 samples of 17 different spices and aromatic herbs that are widely consumed in Spain, and in the Mediterranean diet, in general. Aluminium was determined in the samples mineralized with HNO3 and V2O5, using electrothermal atomization atomic absorption spectroscopy as the analytical technique. The accuracy and precision of the proposed method was verified against an NBS-certified reference material. Precision, expressed as relative standard deviation, ranged from 1.10 to 4.07%. The results obtained from recovery studies were of 97.90 +/- 1.20. Aluminium concentrations ranged from 3.74 to 56.50 microg/g (dry wt.). The presence of this metal was detected in all the samples we analysed.

  20. Aluminium and zinc phosphide poisoning.

    PubMed

    Proudfoot, Alex T

    2009-02-01

    Aluminium and zinc phosphides are highly effective insecticides and rodenticides and are used widely to protect grain in stores and during its transportation. Acute poisoning with these compounds may be direct due to ingestion of the salts or indirect from accidental inhalation of phosphine generated during their approved use. Both forms of poisoning are mediated by phosphine which has been thought to be toxic because it inhibits cytochrome c oxidase. While phosphine does inhibit cytochrome C oxidase in vitro, the inhibition is much less in vivo. It has been shown recently in nematodes that phosphine rapidly perturbs mitochondrial morphology, inhibits oxidative respiration by 70%, and causes a severe drop in mitochondrial membrane potential. This failure of cellular respiration is likely to be due to a mechanism other than inhibition of cytochrome C oxidase. In addition, phosphine and hydrogen peroxide can interact to form the highly reactive hydroxyl radical and phosphine also inhibits catalase and peroxidase; both mechanisms result in hydroxyl radical associated damage such as lipid peroxidation. The major lethal consequence of phosphide ingestion, profound circulatory collapse, is secondary to factors including direct effects on cardiac myocytes, fluid loss, and adrenal gland damage. In addition, phosphine and phosphides have corrosive actions. There is usually only a short interval between ingestion of phosphides and the appearance of systemic toxicity. Phosphine-induced impairment of myocardial contractility and fluid loss leads to circulatory failure, and critically, pulmonary edema supervenes, though whether this is a cardiogenic or non-cardiogenic is not always clear. Metabolic acidosis, or mixed metabolic acidosis and respiratory alkalosis, and acute renal failure are frequent. Other features include disseminated intravascular coagulation, hepatic necrosis and renal failure. There is conflicting evidence on the occurrence of magnesium disturbances. There

  1. Aluminium and the human breast.

    PubMed

    Darbre, P D

    2016-06-01

    The human population is exposed to aluminium (Al) from diet, antacids and vaccine adjuvants, but frequent application of Al-based salts to the underarm as antiperspirant adds a high additional exposure directly to the local area of the human breast. Coincidentally the upper outer quadrant of the breast is where there is also a disproportionately high incidence of breast cysts and breast cancer. Al has been measured in human breast tissues/fluids at higher levels than in blood, and experimental evidence suggests that at physiologically relevant concentrations, Al can adversely impact on human breast epithelial cell biology. Gross cystic breast disease is the most common benign disorder of the breast and evidence is presented that Al may be a causative factor in formation of breast cysts. Evidence is also reviewed that Al can enable the development of multiple hallmarks associated with cancer in breast cells, in particular that it can cause genomic instability and inappropriate proliferation in human breast epithelial cells, and can increase migration and invasion of human breast cancer cells. In addition, Al is a metalloestrogen and oestrogen is a risk factor for breast cancer known to influence multiple hallmarks. The microenvironment is established as another determinant of breast cancer development and Al has been shown to cause adverse alterations to the breast microenvironment. If current usage patterns of Al-based antiperspirant salts contribute to causation of breast cysts and breast cancer, then reduction in exposure would offer a strategy for prevention, and regulatory review is now justified. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Aluminium ring pulls: an invisible foreign body.

    PubMed Central

    Stewart, G D; Lakshmi, M V; Jackson, A

    1994-01-01

    The aluminium ring pulls associated with the latest designs of drinks cans can be relatively easily detached from their mounting on the top of the can and subsequently aspirated. Their small size predisposes them to lodge as foreign bodies (FBs) in the throat. The similarity of atomic number between soft tissue (7.5) and aluminium (13) makes detection of these FBs difficult on soft tissue radiography. If aspiration is suspected direct visualization and removal may be indicated even if radiography is negative. Images Fig. 1 Fig. 2 Fig. 3 PMID:7804592

  3. Serum aluminium and cobalt levels after ceramic-on-ceramic and metal-on-metal total hip replacement.

    PubMed

    Grübl, A; Weissinger, M; Brodner, W; Gleiss, A; Giurea, A; Gruber, M; Pöll, G; Meisinger, V; Gottsauner-Wolf, F; Kotz, R

    2006-08-01

    In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

  4. Fires in storages of LFO: Analysis of hazard of structural collapse of steel-aluminium containers.

    PubMed

    Rebec, A; Kolšek, J; Plešec, P

    2016-04-05

    Pool fires of light fuel oil (LFO) in above-ground storages with steel-aluminium containers are discussed. A model is developed for assessments of risks of between-tank fire spread. Radiative effects of the flame body are accounted for by a solid flame radiation model. Thermal profiles evolved due to fire in the adjacent tanks and their consequential structural response is pursued in an exact (materially and geometrically non-linear) manner. The model's derivation is demonstrated on the LFO tank storage located near the Port of Koper (Slovenia). In support of the model, data from literature are adopted where appropriate. Analytical expressions are derived correspondingly for calculations of emissive characteristics of LFO pool fires. Additional data are collected from experiments. Fire experiments conducted on 300cm diameter LFO pans and at different wind speeds and high-temperature uniaxial tension tests of the analysed aluminium alloys types 3xxx and 6xxx are presented. The model is of an immediate fire engineering practical value (risk analyses) or can be used for further research purposes (e.g. sensitivity and parametric studies). The latter use is demonstrated in the final part of the paper discussing possible effects of high-temperature creep of 3xxx aluminium. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Aluminium in over-the-counter drugs: risks outweigh benefits?

    PubMed

    Reinke, Claudia M; Breitkreutz, Jörg; Leuenberger, Hans

    2003-01-01

    In the early 1970s, aluminium toxicity was first implicated in the pathogenesis of clinical disorders in patients with chronic renal failure involving bone (renal osteomalacia) or brain tissue (dialysis encephalopathy). Before that time the toxic effects of aluminium ingestion were not considered to be a major concern because absorption seemed unlikely to occur. Meanwhile, aluminium toxicity has been investigated in countless epidemiological and clinical studies as well as in animal experiments and many papers have been published on the subject. It is now commonly acknowledged that aluminium toxicity can be induced by infusion of aluminium-contaminated dialysis fluids, by parenteral nutrition solutions, and by oral exposure as a result of aluminium-containing pharmaceutical products such as aluminium-based phosphate binders or antacid intake. Over-the-counter antacids are the most important source for human aluminium exposure from a quantitative point of view. However, aluminium can act as a powerful neurological toxicant and provoke embryonic and fetal toxic effects in animals and humans after gestational exposure. Despite these facts, the patient information leaflets from European antacids that are available OTC show substantial differences regarding warnings from aluminium toxicity. It seems advisable that all patients should receive the same information on aluminium toxicity from patient information leaflets, in particular with regard to the increased absorption through concomitant administration with citrate-containing beverages and the use of such antacids during pregnancy.

  6. Aluminium in Alzheimer's disease: are we still at a crossroad?

    PubMed

    Gupta, Veer Bala; Anitha, S; Hegde, M L; Zecca, L; Garruto, R M; Ravid, R; Shankar, S K; Stein, R; Shanmugavelu, P; Jagannatha Rao, K S

    2005-01-01

    Aluminium, an environmentally abundant non-redox trivalent cation has long been implicated in the pathogenesis of Alzheimer's disease (AD). However, the definite mechanism of aluminium toxicity in AD is not known. Evidence suggests that trace metal homeostasis plays a crucial role in the normal functioning of the brain, and any disturbance in it can exacerbate events associated with AD. The present paper reviews the scientific literature linking aluminium with AD. The focus is on aluminium levels in brain, region-specific and subcellular distribution, its relation to neurofibrillary tangles, amyloid beta, and other metals. A detailed mechanism of the role of aluminium in oxidative stress and cell death is highlighted. The importance of complex speciation chemistry of aluminium in relation to biology has been emphasized. The debatable role of aluminium in AD and the cross-talk between aluminium and genetic susceptibility are also discussed. Finally, it is concluded based on extensive literature that the neurotoxic effects of aluminium are beyond any doubt, and aluminium as a factor in AD cannot be discarded. However, whether aluminium is a sole factor in AD and whether it is a factor in all AD cases still needs to be understood.

  7. Effect of volatile elements on porosity formation in solidifying alloys

    NASA Astrophysics Data System (ADS)

    Couturier, G.; Rappaz, M.

    2006-03-01

    Besides dissolved gases such as hydrogen, the partial vapour pressure of volatile solute elements, such as zinc, has been accounted for in equations governing the nucleation and growth of pores in solidifying alloys. In particular, a simple analytical solution giving the porosity fraction as a function of the fraction of solid is proposed. This solution is then used to study the influence of zinc on porosity formation in aluminium- and copper-base alloys. It is shown that the zinc vapour pressure is too low to increase the porosity of aluminium-base alloys, whereas it has a significant effect in brasses. Implementing this contribution into an existing software which calculates the pressure drop in the mushy zone and the segregation of dissolved gases, simulations have been performed in order to assess in more realistic situations the influence of volatile solute elements on porosity.

  8. The interrelationship between silicon and aluminium in the biological effects of aluminium.

    PubMed

    Birchall, J D

    1992-01-01

    It is well established that aluminium is toxic at the cellular level and that pathological symptoms follow its entry into organisms (plants, fish, humans) when the normal exclusion mechanisms fail or are bypassed, as for example in renal dialysis. The present debate concerns the availability of environmental aluminium and the possible impact of its slow and insidious absorption and accumulation in vulnerable individuals. Silicon is considered as essential element but the mechanisms underlying its essentiality remain unknown and binding of the element (through oxygen) with biomolecules has not been demonstrated. There is, however, a unique affinity between aluminium and silicon, not only in solid state chemistry ([AlO4]5- and [SiO4]4- are isostructural), but also in aqueous solution chemistry as illustrated by the synthesis of zeolite from aluminate and silicate anions at high pH and under hydrothermal conditions. This affinity exists also in very dilute solution (< 10(-5) M) at near-neutral pH when hydroxyalumino-silicate species form. These species mediate the bioavailability and cellular toxicity of aluminium. The observed effects of silicon deficiency can be attributed to consequential aluminium availability. There are important implications for the epidemiology and biochemistry of aluminium-induced disorders and any consideration of one element must include the other.

  9. An ultrafast rechargeable aluminium-ion battery

    NASA Astrophysics Data System (ADS)

    Lin, Meng-Chang; Gong, Ming; Lu, Bingan; Wu, Yingpeng; Wang, Di-Yan; Guan, Mingyun; Angell, Michael; Chen, Changxin; Yang, Jiang; Hwang, Bing-Joe; Dai, Hongjie

    2015-04-01

    The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage. Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability, together with three-electron-redox properties leading to high capacity. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration, low cell discharge voltage (about 0.55 volts ref. 5), capacitive behaviour without discharge voltage plateaus (1.1-0.2 volts or 1.8-0.8 volts) and insufficient cycle life (less than 100 cycles) with rapid capacity decay (by 26-85 per cent over 100 cycles). Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g-1 and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g-1 (equivalent to ~3,000 W kg-1), and to withstand more than 7,500 cycles without capacity decay.

  10. Molecular breeding of cereals for aluminium resistance

    USDA-ARS?s Scientific Manuscript database

    Aluminium (Al3+) toxicity is the primary factor limiting crop production on acidic soils worldwide. In addition to an application of lime for soil amelioration, Al3+ resistant plant varieties have been deployed to raise productivity on such hostile soils. This has been possible due to the exploita...

  11. Effect of aluminium chloride on human spermatozoa

    SciTech Connect

    Kaur, S.

    1988-03-01

    Aluminium (Al), which is the most prevalent metal in the earth's crust, has been implicated as an etiological factor in a variety of clinical disorders. Only recently Al has been discussed in the pathogenesis of the parenteral nutrition - associated liver disease. Included in this report are the preliminary findings on its effects on the reproductive functions of human beings.

  12. Indentation of aluminium foam at low velocity

    NASA Astrophysics Data System (ADS)

    Shi, Xiaopeng; Miao, Yinggang; Liu, Shuangyan; Li, Yulong; Lu, Guoxing

    2015-09-01

    The indentation behaviour of aluminium foams at low velocity (10 m/s ˜ 30 m/s) was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ˜10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ˜10 m/s velocity may be caused by plastic wave effect.

  13. Toxicity of dissolved and precipitated aluminium to marine diatoms.

    PubMed

    Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

    2016-05-01

    Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as <0.025μm filtered, <0.45μm filtered (dissolved) and unfiltered (total) present in solution over the 72-h bioassay. The chronic population growth rate inhibition after aluminium exposure varied between diatom species. C. closterium was the most sensitive species (10% inhibition of growth rate (72-h IC10) of 80 (55-100)μg Al/L (95% confidence limits)) while M. polymorphus (540 (460-600)μg Al/L) and P. tricornutum (2100 (2000-2200)μg Al/L) were less sensitive (based on measured total aluminium). Dissolved aluminium was the primary contributor to toxicity in C. closterium, while a combination of dissolved and precipitated aluminium forms contributed to toxicity in M. polymorphus. In contrast, aluminium toxicity to the most tolerant diatom P. tricornutum was due predominantly to precipitated aluminium. Preliminary investigations revealed the sensitivity of C. closterium and M. polymorphus to aluminium was influenced by initial cell density with aluminium toxicity significantly (p<0.05) increasing with initial cell density from 10(3) to 10(5)cells/mL. No effects on plasma membrane permeability were observed for any of the three diatoms suggesting that mechanisms of aluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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.

  15. Bone aluminium in haemodialysed patients and in rats injected with aluminium chloride: relationship to impaired bone mineralisation.

    PubMed Central

    Ellis, H A; McCarthy, J H; Herrington, J

    1979-01-01

    Iliac bone aluminium was determined by neutron activation analysis in 34 patients with chronic renal failure and in eight control subjects. In 17 patients treated by haemodialysis there was a significant increase in the amount of aluminium (mean +/- SE = 152 +/- 30 ppm bone ash). In eight patients treated by haemodialysis and subsequent renal transplantation, bone aluminium was still significantly increased (92 +/- 4.5 ppm bone ash) but was less than in the haemodialysed patients. In some patients aluminium persisted in bone for many years after successful renal transplantation. There was no relationship between hyperparathyroidism and bone aluminium. Although no statistically significant relationship was found between the mineralisation status of bone and bone aluminium, patients dialysed for the longest periods tended to be those with the highest levels of aluminium, osteomalacia, and dialysis encephalopathy. In 20 rats given daily intraperitoneal injections of aluminium chloride for periods of up to three months, there was accumulation of aluminium in bone (163 +/- 9 ppm ash) to levels comparable to those obtained in the dialysis patients, and after about eight weeks osteomalacia developed. The increased bone aluminium and osteomalacia persisted after injections had been stopped for up to 49 days, although endochondral ossification was restored to normal. As a working hypothesis it is suggested that aluminium retained in the bone of the dialysis patients and the experimental animals interferes with normal mineralisation. Images Fig. 5 Fig. 6 PMID:389958

  16. Radiation-stimulated diffusion in Al-Si alloys

    NASA Astrophysics Data System (ADS)

    Kiv, A.; Fuks, D.; Munitz, A.; Zenou, V.; Moiseenko, N.

    A di-vacancy low-temperature diffusion is proposed to explain diffusion-controlled processes in Al-Si alloys responsible for neutron-induced silicon precipitation. Ab initio calculations of potential barriers for Si atom hopping in aluminium lattice showed that in the case of di-vacancy diffusion, they are small compared with that of mono-vacancy diffusion. The low temperature diffusivity of mono-vacancies is too small to account for the measured Si diffusivities in aluminium. The dependencies of radiation-stimulated diffusion on the neutron flux and on the temperature are obtained and can be used for the experimental verification of the developed model.

  17. Cell damage in vitro following direct contact with fine particles of titanium, titanium alloy and cobalt-chrome-molybdenum alloy.

    PubMed

    Evans, E J

    1994-07-01

    Fibroblastic cells in vitro were exposed to powders of titanium, titanium-aluminium-vanadium alloy and cobalt-chrome-molybdenum (Co-Cr-Mo) alloy, either in direct contact with the cells or separated from the cells by a microporous membrane. Fine particles of all the materials reduced cell growth when in direct contact with cells, but only the finest particles of Co-Cr-Mo alloy caused cell damage through the microporous membrane. This provides further evidence that there is a mechanism of cell damage in vitro which depends on a direct interaction between cells and particles and is largely independent of the chemical nature of the particle.

  18. Investigation of Structure, Properties and Deformation Mechanisms of Elevated Temperature Al Alloys with High Specific Properties

    DTIC Science & Technology

    2004-01-31

    ultimate strength is 10 – 12 %. Maximum strength after heat treatment by T6 mode was achieved in L11 alloy with scandium and hafnium . It is equal to about...presence of elongated, oriented along the direction of deformation grains of α-solid solution of the main components in aluminium , as well as η(MgZn2), T...metal properties in different sections of the welded joint. References 1. Commercial aluminium alloys: Ref. Book / Alieva S.G., Altman N.B

  19. Alloy materials

    DOEpatents

    Hans Thieme, Cornelis Leo; Thompson, Elliott D.; Fritzemeier, Leslie G.; Cameron, Robert D.; Siegal, Edward J.

    2002-01-01

    An alloy that contains at least two metals and can be used as a substrate for a superconductor is disclosed. The alloy can contain an oxide former. The alloy can have a biaxial or cube texture. The substrate can be used in a multilayer superconductor, which can further include one or more buffer layers disposed between the substrate and the superconductor material. The alloys can be made a by process that involves first rolling the alloy then annealing the alloy. A relatively large volume percentage of the alloy can be formed of grains having a biaxial or cube texture.

  20. A numerical analysis of empty and foam-filled aluminium conical tubes under oblique impact loading

    NASA Astrophysics Data System (ADS)

    Mat, Fauziah; Ismail, Khairul Azwan; Yaacob, Sazali

    2015-05-01

    In real impact applications, an energy absorber rarely sustains dynamic loading either axial or oblique but a combination of both. Established studies have proved that thin-walled tube is an excellent energy absorber under dynamic loading. Furthermore, the introduction of foam filling successfully enhanced the energy absorption capacity of thin-walled tube. However, the understanding of its response under oblique loading has yet been fully explored. Moreover, emerging in automotive industry has lead to increase interests on lightweight materials such as aluminium alloy. As such, this paper presents the crushing behaviour of empty and foam-filled aluminium alloy (AA6061-T6) conical tubes under oblique impact loading using a validated nonlinear finite element (FE) code, LS-DYNA. The study aims to assess the effect of foam filling on the energy absorption of AA6061-T6 tubes for variations in filler density. In fact, to the best of our knowledge, this study is the first attempt to evaluate a response of empty and foam-filled aluminum conical tube by using an experimentally validated model under oblique dynamic loading conditions. Good correlations between the numerical and experimental results were observed. The study show that initial peak force and the energy absorption increase with increasing filler density under axial and oblique loading. On the other hand, the effect of foam filling (0.534 g/cm3 aluminium foam filler) is less pronounced for the initial peak force under axial impact loading. Furthermore, the initial peak force and dynamic force of empty and foam-filled AA6061-T6 conical tubes decrease as the load angle increases from 0 deg to 20 deg hence reduces the energy absorption capacity.

  1. Fabrication of ultra-fine grained aluminium tubes by RTES technique

    SciTech Connect

    Jafarzadeh, H. Abrinia, K.

    2015-04-15

    Recently, repetitive tube expansion and shrinking have been exploited as a means for producing ultra-fine grained and nano-crystalline microstructures for magnesium alloy tubes. This method includes two different half-cycles and was based on pressing a tubular part through an angular channel die with two shear zones. Since the aluminium alloys are the most widely used materials in industries, in this study, repetitive tube expansion and shrinking as a new severe plastic deformation technique was applied to commercially pure aluminium for fabricating ultra-fine grained aluminium tubes for the first time and the ability of this process in significant grain refinement is determined even after single cycle. Transmission electron microscopy and X-ray diffraction were used to evaluate the microstructure of the repetitive tube expansion and shrinking processed materials and the examinations showed ultra-fine grains with the average grain size of 320 nm after one cycle of repetitive tube expansion and shrinking. The yield strength, ultimate tensile strength increased notably by the factor of 2.17 and 1.27 respectively, after one cycle of repetitive tube expansion and shrinking, whereas the elongation to failure as well as the uniform elongation decreased. Furthermore, micro-hardness distribution through the part's section proposed the hardness increasing to ~ 55 HV from the initial value of ~ 28 HV after one cycle of repetitive tube expansion and shrinking. - Highlights: • RTES was introduced for fabricating the UFGed AA1050 tubes for the first time. • Nano-grained AA1050 tube was obtained by RTES process. • Grain size of ~ 320 nm was obtained after two half-cycles of RTES process. • Yield and ultimate strength increased by the factor of 2.17 and 1.27 respectively. • The microhardness increased to ~ 55 HV from the initial value of ~ 28 HV.

  2. Microemulsion extraction separation and determination of aluminium species by spectrofluorimetry.

    PubMed

    Lu, Jusheng; Tian, Jiuying; Guo, Na; Wang, Yan; Pan, Yichun

    2011-01-30

    A simple and sensitive microemulsion extraction separation method was developed for the speciation of aluminium in tea samples by spectrofluorimetry. With 8-hydroxyquinoline (8-HQ) as the chelating agent and Triton X-100 Winsor II microemulsion as the extractant, separation of aluminium species in different pH solutions was achieved by microemulsion extraction. The formation of microemulsion, the conditions of extraction and determination of aluminium species were studied. The results showed that, the contents of aluminium species in tea leaves and infusions samples, such as total aluminium, total soluble aluminium, total granular aluminium, inorganic aluminium except Al-F, and (Al-F+Al-org), were obtained successfully under the optimal conditions. The limit of detection was 0.23 μg L(-1) in pH 9.5 solution, and 0.59 μg L(-1) in pH 6.0 solution respectively; the precision (RSD) for 11 replicate measurements of 10 μg L(-1) aluminium was 2.1% in pH 9.5 solution, and 2.8% in pH 6.0 solution respectively; the recoveries for the spiked samples were 96.8-103.5%. The proposed method is simple and efficient, which has been applied to the speciation of aluminium in tea samples with satisfactory results.

  3. Aluminium in brain tissue in familial Alzheimer's disease.

    PubMed

    Mirza, Ambreen; King, Andrew; Troakes, Claire; Exley, Christopher

    2017-03-01

    The genetic predispositions which describe a diagnosis of familial Alzheimer's disease can be considered as cornerstones of the amyloid cascade hypothesis. Essentially they place the expression and metabolism of the amyloid precursor protein as the main tenet of disease aetiology. However, we do not know the cause of Alzheimer's disease and environmental factors may yet be shown to contribute towards its onset and progression. One such environmental factor is human exposure to aluminium and aluminium has been shown to be present in brain tissue in sporadic Alzheimer's disease. We have made the first ever measurements of aluminium in brain tissue from 12 donors diagnosed with familial Alzheimer's disease. The concentrations of aluminium were extremely high, for example, there were values in excess of 10μg/g tissue dry wt. in 5 of the 12 individuals. Overall, the concentrations were higher than all previous measurements of brain aluminium except cases of known aluminium-induced encephalopathy. We have supported our quantitative analyses using a novel method of aluminium-selective fluorescence microscopy to visualise aluminium in all lobes of every brain investigated. The unique quantitative data and the stunning images of aluminium in familial Alzheimer's disease brain tissue raise the spectre of aluminium's role in this devastating disease.

  4. Aspects of fabrication aluminium matrix heterophase composites by suspension method

    NASA Astrophysics Data System (ADS)

    Dolata, A. J.; Dyzia, M.

    2012-05-01

    Composites with an aluminium alloy matrix (AlMMC) exhibit several advantageous properties such as good strength, stiffness, low density, resistance and dimensional stability to elevated temperatures, good thermal expansion coefficient and particularly high resistance to friction wear. Therefore such composites are more and more used in modern engineering constructions. Composites reinforced with hard ceramic particles (Al2O3, SiC) are gradually being implemented into production in automotive or aircraft industries. Another application of AlMMC is in the electronics industry, where the dimensional stability and capacity to absorb and remove heat is used in radiators. However the main problems are still: a reduction of production costs, developing methods of composite material tests and final product quality assessment, standardisation, development of recycling and mechanical processing methods. AlMMC production technologies, based on liquid-phase methods, and the shaping of products by casting methods, belong to the cheapest production methods. Application of a suspension method for the production of composites with heterophase reinforcement may turn out to be a new material and technological solution. The article presents the material and technological aspects of the transfer procedures for the production of composite suspensions from laboratory scale to a semi-industrial scale.

  5. Laser welding of copper and aluminium battery interconnections

    NASA Astrophysics Data System (ADS)

    De Bono, Paola; Blackburn, Jon

    2015-07-01

    The adoption of lithium-ion and/or super-capacitor battery technologies is a current hot topic in the automotive industry. For both battery types, the terminals and busbars are manufactured from copper (Cu) and/or aluminium-based (Al-based) alloys, as a result of their high electrical and thermal conductivities. Laser welding is considered an attractive process to industry due to its easy automotability, high processing speed and highly repeatable cost-effective processing. However, laser welding of Cu-Cu and Al-Al joints presents several difficulties due to the high surface reflectivity at infrared (IR) wavelengths. This behaviour becomes even more critical when processing thin sheets and foils.This paper summarises recent work performed to develop laser welding techniques suitable for monometallic joining of Cu-Cu and Al-Al electrical interconnections. Laser welding of multiple overlapped foils (with thickness in the range of 17μm-100μm) were investigated.

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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.

  7. Mechanical Properties of SiC, Al2O3 Reinforced Aluminium 6061-T6 Hybrid Matrix Composite

    NASA Astrophysics Data System (ADS)

    Murugan, S. Senthil; Jegan, V.; Velmurugan, M.

    2017-06-01

    This paper contains the investigation of tensile, compression and impact characterization of SiC, Al2O3 reinforced Aluminium 6061-T6 matrix hybrid composite. Hybrid matrix composite fabrication was done by stir casting method. An attempt has been made by keeping Al2O3 percentage (7%) constant and increasing SiC percentage (10, 15, and 20%). After fabricating, the samples were prepared and tested to find out the various mechanical properties like tensile, compressive, and impact strength of the developed composites of different weight % of silicon carbide and Alumina in Aluminium alloy. The main objective of the study is to compare the values obtained and choose the best composition of the hybrid matrix composite from the mechanical properties point of view.

  8. Feet sunk in molten aluminium: The burn and its prevention.

    PubMed

    Alonso-Peña, David; Arnáiz-García, María Elena; Valero-Gasalla, Javier Luis; Arnáiz-García, Ana María; Campillo-Campaña, Ramón; Alonso-Peña, Javier; González-Santos, Jose María; Fernández-Díaz, Alaska Leonor; Arnáiz, Javier

    2015-08-01

    Nowadays, despite improvements in safety rules and inspections in the metal industry, foundry workers are not free from burn accidents. Injuries caused by molten metals include burns secondary to molten iron, aluminium, zinc, copper, brass, bronze, manganese, lead and steel. Molten aluminium is one of the most common causative agents of burns (60%); however, only a few publications exist concerning injuries from molten aluminium. The main mechanisms of lesion from molten aluminium include direct contact of the molten metal with the skin or through safety apparel, or when the metal splash burns through the pants and rolls downward along the leg. Herein, we report three cases of deep dermal burns after 'soaking' the foot in liquid aluminium and its evolutive features. This paper aims to show our experience in the management of burns due to molten aluminium. We describe the current management principles and the key features of injury prevention. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  9. What is the risk of aluminium as a neurotoxin?

    PubMed

    Exley, Christopher

    2014-06-01

    Aluminium is neurotoxic. Its free ion, Al(3+) (aq), is highly biologically reactive and uniquely equipped to do damage to essential cellular (neuronal) biochemistry. This unequivocal fact must be the starting point in examining the risk posed by aluminium as a neurotoxin in humans. Aluminium is present in the human brain and it accumulates with age. The most recent research demonstrates that a significant proportion of individuals older than 70 years of age have a potentially pathological accumulation of aluminium somewhere in their brain. What are the symptoms of chronic aluminium intoxication in humans? What if neurodegenerative diseases such as Alzheimer's disease are the manifestation of the risk of aluminium as a neurotoxin? How might such an (outrageous) hypothesis be tested?

  10. Evaluation of Thrust force in Drilling Woven roving Glass fibre reinforced Aluminium Sandwich laminates with TiAlN coated drill using Taguchi analysis

    NASA Astrophysics Data System (ADS)

    Ramya Devi, G.; Palanikumar, K.

    2017-05-01

    TiAlN is a high-performance coating which outshines in coarse and hard-to-machine materials like cast iron, aluminium alloys, tool steels, and nickel alloys. This paper presents the prediction and evaluation of thrust force and Torque in drilling of Woven roving Glass Fibre Reinforced Plastic and Aluminium sandwich laminate. The Prediction is based on Taguchi method. The experimental results specify that the feed rate and the drill diameter are the most significant factors affecting the thrust force, while the feed rate and spindle speed contribute the most to the surface roughness. In this study, the objective was to establish a correlation between the feed rate, spindle speed and drill diameter with the induced thrust force and Torque in drilling sandwich laminate.

  11. Separation of actinides from irradiated An-Zr based fuel by electrorefining on solid aluminium cathodes in molten LiCl-KCl

    NASA Astrophysics Data System (ADS)

    Souček, P.; Murakami, T.; Claux, B.; Meier, R.; Malmbeck, R.; Tsukada, T.; Glatz, J.-P.

    2015-04-01

    An electrorefining process for metallic spent nuclear fuel treatment is being investigated in ITU. Solid aluminium cathodes are used for homogeneous recovery of all actinides within the process carried out in molten LiCl-KCl eutectic salt at a temperature of 500 °C. As the selectivity, efficiency and performance of solid Al has been already shown using un-irradiated An-Zr alloy based test fuels, the present work was focused on laboratory-scale demonstration of the process using irradiated METAPHIX-1 fuel composed of U67-Pu19-Zr10-MA2-RE2 (wt.%, MA = Np, Am, Cm, RE = Nd, Ce, Gd, Y). Different electrorefining techniques, conditions and cathode geometries were used during the experiment yielding evaluation of separation factors, kinetic parameters of actinide-aluminium alloy formation, process efficiency and macro-structure characterisation of the deposits. The results confirmed an excellent separation and very high efficiency of the electrorefining process using solid Al cathodes.

  12. The aluminium content of infant formulas remains too high.

    PubMed

    Chuchu, Nancy; Patel, Bhavini; Sebastian, Blaise; Exley, Christopher

    2013-10-08

    Recent research published in this journal highlighted the issue of the high content of aluminium in infant formulas. The expectation was that the findings would serve as a catalyst for manufacturers to address a significant problem of these, often necessary, components of infant nutrition. It is critically important that parents and other users have confidence in the safety of infant formulas and that they have reliable information to use in choosing a product with a lower content of aluminium. Herein, we have significantly extended the scope of the previous research and the aluminium content of 30 of the most widely available and often used infant formulas has been measured. Both ready-to-drink milks and milk powders were subjected to microwave digestion in the presence of 15.8 M HNO3 and 30% w/v H2O2 and the aluminium content of the digests was measured by TH GFAAS. Both ready-to-drink milks and milk powders were contaminated with aluminium. The concentration of aluminium across all milk products ranged from ca 100 to 430 μg/L. The concentration of aluminium in two soya-based milk products was 656 and 756 μg/L. The intake of aluminium from non-soya-based infant formulas varied from ca 100 to 300 μg per day. For soya-based milks it could be as high as 700 μg per day. All 30 infant formulas were contaminated with aluminium. There was no clear evidence that subsequent to the problem of aluminium being highlighted in a previous publication in this journal that contamination had been addressed and reduced. It is the opinion of the authors that regulatory and other non-voluntary methods are now required to reduce the aluminium content of infant formulas and thereby protect infants from chronic exposure to dietary aluminium.

  13. The aluminium content of infant formulas remains too high

    PubMed Central

    2013-01-01

    Background Recent research published in this journal highlighted the issue of the high content of aluminium in infant formulas. The expectation was that the findings would serve as a catalyst for manufacturers to address a significant problem of these, often necessary, components of infant nutrition. It is critically important that parents and other users have confidence in the safety of infant formulas and that they have reliable information to use in choosing a product with a lower content of aluminium. Herein, we have significantly extended the scope of the previous research and the aluminium content of 30 of the most widely available and often used infant formulas has been measured. Methods Both ready-to-drink milks and milk powders were subjected to microwave digestion in the presence of 15.8 M HNO3 and 30% w/v H2O2 and the aluminium content of the digests was measured by TH GFAAS. Results Both ready-to-drink milks and milk powders were contaminated with aluminium. The concentration of aluminium across all milk products ranged from ca 100 to 430 μg/L. The concentration of aluminium in two soya-based milk products was 656 and 756 μg/L. The intake of aluminium from non-soya-based infant formulas varied from ca 100 to 300 μg per day. For soya-based milks it could be as high as 700 μg per day. Conclusions All 30 infant formulas were contaminated with aluminium. There was no clear evidence that subsequent to the problem of aluminium being highlighted in a previous publication in this journal that contamination had been addressed and reduced. It is the opinion of the authors that regulatory and other non-voluntary methods are now required to reduce the aluminium content of infant formulas and thereby protect infants from chronic exposure to dietary aluminium. PMID:24103160

  14. Improvement of photodynamic activity of aluminium sulphophthalocyanine due to biotinylation

    NASA Astrophysics Data System (ADS)

    Meerovich, Irina G.; Jerdeva, Victoria V.; Derkacheva, Valentina M.; Meerovich, Gennadii A.; Lukyanets, Eugeny A.; Kogan, Eugenia A.; Savitsky, Alexander P.

    2003-09-01

    The photodynamic activity of dibiotinylated aluminium sulphophthalocyanine in vitro and in vivo were studied. It was obtained that in vitro dibiotinylated aluminium sulphophthalocyanine provides the effective damage of small cell lung carcinoma OAT-75. In vivo dibiotinylated aluminium sulphophthalocyanine causes destruction of tumor (Erlich carcinoma), results in total necrosis of tumor tissue and expresses vascular damage (trombosis and destruction of vascular walls) even in concentration 0.25 mg/kg of a body weight.

  15. Exposure to chemical agents in aluminium potrooms.

    PubMed

    Doko Jelinić, Jagoda; Nola, Iskra Alexandra; Udovicić, Ruzica; Ostojić, D; Zuskin, Eugenija

    2007-01-01

    To assess the effects of modernization of aluminium production on reducing the chemical health hazards in the working environment in aluminium potrooms (smelter). Modernization included the introduction ofa technique of point feeding of alumina and aluminium fluoride into the pots, semi-automatic equipment and computerized control. Periodical environmental measurements of chemical substances, dusts containing alumina and fluorides, and gases, i.e., carbon monoxide, carbon dioxide, sulphur dioxide, hydrogen fluoride, nitrogen dioxide, and difluorosulphide, were performed at the same workplaces before (1986-1988) and sixteen years later, after modernization (2004). The measured values were compared with the recommended occupational safety and health standards. The concentrations of total dust (alumina and fluorides) and gases, i.e., carbon monoxide, carbon dioxide, sulphur dioxide, hydrogen fluoride and phenol, were above the recommended standards in 76.6% (95/124) of the samples before modernization and in only 23.8% (57/240) of the samples tested after modernization. Before modernization in almost all jobs the workers were simultaneously exposed to higher concentrations of all chemical agents present in the working environment. After modernization high concentrations of hydrogen fluoride were the primary pollutant in this plant (GM = 4.5451 ppm), while the presence of other gases was significantly reduced. Dusts containing alumina and fluorides and hydrogen fluoride gas were still present in considerable concentrations in the working environments of jobs such as changing and covering of anodes. The modernization of the aluminium smelter plant reduced the concentrations of the most harmful substances in the working environment and reduced the number of jobs where workers were simultaneously exposed to a variety of health hazards.

  16. An ultrafast rechargeable aluminium-ion battery.

    PubMed

    Lin, Meng-Chang; Gong, Ming; Lu, Bingan; Wu, Yingpeng; Wang, Di-Yan; Guan, Mingyun; Angell, Michael; Chen, Changxin; Yang, Jiang; Hwang, Bing-Joe; Dai, Hongjie

    2015-04-16

    The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage. Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability, together with three-electron-redox properties leading to high capacity. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration, low cell discharge voltage (about 0.55 volts; ref. 5), capacitive behaviour without discharge voltage plateaus (1.1-0.2 volts or 1.8-0.8 volts) and insufficient cycle life (less than 100 cycles) with rapid capacity decay (by 26-85 per cent over 100 cycles). Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g(-1) and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g(-1) (equivalent to ~3,000 W kg(-1)), and to withstand more than 7,500 cycles without capacity decay.

  17. Structural engineering of nanoporous anodic aluminium oxide by pulse anodization of aluminium.

    PubMed

    Lee, Woo; Schwirn, Kathrin; Steinhart, Martin; Pippel, Eckhard; Scholz, Roland; Gösele, Ulrich

    2008-04-01

    Nanoporous anodic aluminium oxide has traditionally been made in one of two ways: mild anodization or hard anodization. The first method produces self-ordered pore structures, but it is slow and only works for a narrow range of processing conditions; the second method, which is widely used in the aluminium industry, is faster, but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the mild and hard anodization processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic aluminium oxide films while maintaining high throughput. We use pulse anodization to delaminate a single as-prepared anodic film into a stack of well-defined nanoporous alumina membrane sheets, and also to fabricate novel three-dimensional nanostructures.

  18. The potential role of aluminium in Alzheimer's disease.

    PubMed

    Campbell, Arezoo

    2002-01-01

    Aluminium is a trivalent cation that does not undergo redox changes. It has, nonetheless, been implicated in a variety of neurological disorders that have been associated with an increase in the formation of reactive oxygen species (ROS). The exact mechanism of aluminium toxicity is not known. However, accumulating evidence suggests that the metal can potentiate oxidative and inflammatory events, leading to tissue damage. A review of the epidemiological and clinical evidence linking aluminium to Alzheimer's disease (AD) is presented. The article discusses the role of aluminium in two mechanisms that have been linked to neurodegenerative disorders, including AD. Studies are summarized that describe how aluminium can potentiate iron-induced oxidative events. Involvement of aluminium in inflammatory responses, mediated by interleukins and other inflammatory cytokines, is also discussed. Although a direct relationship between aluminium and AD has not been clearly demonstrated, a detailed mechanistic basis for the hypothesis that aluminium may exacerbate events associated with AD is clearly emerging. The results discussed here have broad implications for the role played by aluminium and other metals in neurodegenerative diseases, and suggest that long-term exposure to supra-physiological amounts these metals should be avoided.

  19. [Effect of casting techniques on castability of copper-aluminum alloys].

    PubMed

    Scaranelo, R M; Bombonatti, P E; de Barros, L E; Pellizzer, A J

    1990-01-01

    It was evaluated the castability of four copper-aluminium alloy according the melting casting method used. The specimens were made using polyester mesh screen, with 11 x 11 filaments of 0.26 mm thick, fixed along of two adjacent edges in wax bar, with the sprue attached at their junction. The alloys were in an electrical casting machine and a centrifugal casting machine with an air/gas torch. The castability values were obtained by the percentage of completed segments of the resulting cast alloy screen. It was verified that the use of the electrical casting machine produced higher castability values to the copper-aluminium alloys than those produced by a centrifugal casting machine with an air/gas torch.

  20. Plasma Electrolytic Oxidation (PEO) Coatings on an A356 Alloy for Improved Corrosion and Wear Resistance

    NASA Astrophysics Data System (ADS)

    Peng, Zhijing

    Plasma electrolytic oxidizing (PEO) is an advanced technique that has been used to deposit thick and hard ceramic coatings on aluminium (Al) alloys. This work was however to use the PEO process to produce thin ceramic oxide coatings on an A356 Al alloy for improving corrosion and wear resistance of the alloy. Effects of current density and treatment time on surface morphologies and thickness of the PEO coatings were investigated. The improvement of galvanic corrosion properties of the coated A356 alloy vs. steel and carbon fibre were evaluated in E85 fuel or NaCl environments. Tribological properties of the coatings were studied with comparison to the uncoated A356 substrate and other commercially-used engine bore materials. The research results indicated that the PEO coatings could have excellent tribological and corrosion properties for aluminium engine applications.

  1. Thermal treatment, grain boundary composition and intergranular attack resistance of Alloy 690

    SciTech Connect

    Smith, A.J.; Stratton, R.P.

    1992-12-31

    Commercial Alloy 690 PWR steam generator tubes and experimentally produced alloys with varying amounts of carbon, aluminium and titanium have been examined. After simulated mill annealing and thermal treatment, the microstructure and corrosion behaviour in corrosion tests have been investigated. Stress corrosion resistance of selected alloy 690 tubes and experimental alloys has been examined with environments based on pure water, sodium hydroxide and sodium hydroxide + sodium sulphate solutions. Effects of aluminium content and the thermal treatments on the susceptibility to intergranular attack have been examined, although they appear not to be very significant to the amounts of IGA. Samples used in thermal treatments have been further examined with a dedicated scanning transmission electron microscope to show compositional changes at grain boundaries.

  2. Ratcheting fatigue behaviour of Al-7075 T6 alloy: Influence of stress parameters

    NASA Astrophysics Data System (ADS)

    Amarnath, Lala; Bhattacharjee, Antara; Dutta, K.

    2016-02-01

    The use of aluminium and aluminium based alloys are increasing rapidly on account of its high formability, good thermal and electrical conductivity, high strength and lightness. Aluminium alloys are extensively used in aerospace, automobile, marine and space research industries and are also put into structural applications where chances of fatigue damage cannot be ruled out. In the current work, it is intended to study the ratcheting fatigue behavior of 7075-T6 aluminium alloy at room temperature. This Al alloy is potentially used in aviation, marine and automotive components as well as in bicycle parts, rock mounting equipment and parts of ammunition where there is every chance of failure of the parts due to deformation caused by ratcheting. Ratcheting is the process of accruement of plastic stain produced when a component is subjected to asymmetric cyclic loading under the influence of low cycle fatigue. To accomplish the requirements of the projected research, stress-controlled cyclic loading experiments were done using a ±250 kN servo-hydraulic universal testing machine (Instron: 8800R). The effect of stress parameters such as mean stress and stress amplitude were investigated on the ratcheting behavior of the selected aluminium alloy. It was observed that, ratcheting strain increased with increase in the value of stress amplitude at any constant mean stress while a saturation in strain accumulation attained in the investigated material after around 10-20 cycles, under all test conditions. The analyses of hysteresis loop generated during cyclic loading indicate that the material exhibits cyclic hardening in the initial fifty cycles which gets softened in further loading up to about 70-80 cycles and finally attains a steady state. The increase in the ratcheting strain value with stress parameters happens owing to increased deformation domain during cycling. The cyclic hardening accompanied by softening is correlated with characteristic precipitation features of

  3. Reciprocating Sliding Behaviour of Solid Lubricant Coating over Modified Titanium Alloy Surfaces

    NASA Astrophysics Data System (ADS)

    Jothi Prakash, V. M.; Sathish, S.; Gopalakrishnan, T.; Venugopal, S.

    2017-03-01

    Tribological behaviour of contacting surfaces rigid sphere is using flat plate the with influence of normal and tangential loading (shear traction) is analysed using FEA model and surfaces being coated on flat plate by Titanium Alloy, Aluminium Alloy Molybdenum Di-sulphide. The finite element model facilitates to Evaluating the surface variables like contact stress distribution with the surface level and surface, contact pressure, shear stress and displacement. The finite element solution is validated through the hertz solution and on the successful verification.

  4. Prevalence of beryllium sensitization among aluminium smelter workers

    PubMed Central

    Slade, M. D.; Cantley, L. F.; Kirsche, S. R.; Wesdock, J. C.; Cullen, M. R.

    2010-01-01

    Background Beryllium exposure occurs in aluminium smelters from natural contamination of bauxite, the principal source of aluminium. Aims To characterize beryllium exposure in aluminium smelters and determine the prevalence rate of beryllium sensitization (BeS) among aluminium smelter workers. Methods A population of 3185 workers from nine aluminium smelters owned by four different aluminium-producing companies were determined to have significant beryllium exposure. Of these, 1932 workers participated in medical surveillance programmes that included the serum beryllium lymphocyte proliferation test (BeLPT), confirmation of sensitization by at least two abnormal BeLPT test results and further evaluation for chronic beryllium disease in workers with BeS. Results Personal beryllium samples obtained from the nine aluminium smelters showed a range of <0.01–13.00 μg/m3 time-weighted average with an arithmetic mean of 0.25 μg/m3 and geometric mean of 0.06 μg/m3. Nine workers were diagnosed with BeS (prevalence rate of 0.47%, 95% confidence interval = 0.21–0.88%). Conclusions BeS can occur in aluminium smelter workers through natural beryllium contamination of the bauxite and further concentration during the refining and smelting processes. Exposure levels to beryllium observed in aluminium smelters are similar to those seen in other industries that utilize beryllium. However, compared with beryllium-exposed workers in other industries, the rate of BeS among aluminium smelter workers appears lower. This lower observed rate may be related to a more soluble form of beryllium found in the aluminium smelting work environment as well as the consistent use of respiratory protection. PMID:20610489

  5. There is (still) too much aluminium in infant formulas

    PubMed Central

    2010-01-01

    Background Infant formulas are sophisticated milk-based feeds for infants which are used as a substitute for breast milk. Historically they are known to be contaminated by aluminium and in the past this has raised health concerns for exposed infants. We have measured the aluminium content of a number of widely used infant formulas to determine if their contamination by aluminium and consequent issues of child health persists. Methods Samples of ready-made milks and powders used to make milks were prepared by microwave digestion of acid/peroxide mixtures and their aluminium content determined by THGA. Results The concentration of aluminium in ready-made milks varied from ca 176 to 700 μg/L. The latter concentration was for a milk for preterm infants. The aluminium content of powders used to make milks varied from ca 2.4 to 4.3 μg/g. The latter content was for a soya-based formula and equated to a ready-to-drink milk concentration of 629 μg/L. Using the manufacturer's own guidelines of formula consumption the average daily ingestion of aluminium from infant formulas for a child of 6 months varied from ca 200 to 600 μg of aluminium. Generally ingestion was higher from powdered as compared to ready-made formulas. Conclusions The aluminium content of a range of well known brands of infant formulas remains high and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies. Recent research demonstrating the vulnerability of infants to early exposure to aluminium serves to highlight an urgent need to reduce the aluminium content of infant formulas to as low a level as is practically possible. PMID:20807425

  6. Long-term effects of aluminium dust inhalation.

    PubMed

    Peters, Susan; Reid, Alison; Fritschi, Lin; de Klerk, Nicholas; Musk, A W Bill

    2013-12-01

    During the 1950s and 1960s, aluminium dust inhalation was used as a potential prophylaxis against silicosis in underground miners, including in Australia. We investigated the association between aluminium dust inhalation and cardiovascular, cerebrovascular and Alzheimer's diseases in a cohort of Australian male underground gold miners. We additionally looked at pneumoconiosis mortality to estimate the effect of the aluminium therapy. SMRs and 95% CI were calculated to compare mortality of the cohort members with that of the Western Australian male population (1961-2009). Internal comparisons on duration of aluminium dust inhalation were examined using Cox regression. Aluminium dust inhalation was reported for 647 out of 1894 underground gold miners. During 42 780 person-years of follow-up, 1577 deaths were observed. An indication of increased mortality of Alzheimer's disease among miners ever exposed to aluminium dust was found (SMR=1.38), although it was not statistically significant (95% CI 0.69 to 2.75). Rates for cardiovascular and cerebrovascular death were above population levels, but were similar for subjects with or without a history of aluminium dust inhalation. HRs suggested an increasing risk of cardiovascular disease with duration of aluminium dust inhalation (HR=1.02, 95% CI 1.00 to 1.04, per year of exposure). No difference in the association between duration of work underground and pneumoconiosis was observed between the groups with or without aluminium dust exposure. No protective effect against silicosis was observed from aluminium dust inhalation. Conversely, exposure to aluminium dust may possibly increase the risk of cardiovascular disease and dementia of the Alzheimer's type.

  7. There is (still) too much aluminium in infant formulas.

    PubMed

    Burrell, Shelle-Ann M; Exley, Christopher

    2010-08-31

    Infant formulas are sophisticated milk-based feeds for infants which are used as a substitute for breast milk. Historically they are known to be contaminated by aluminium and in the past this has raised health concerns for exposed infants. We have measured the aluminium content of a number of widely used infant formulas to determine if their contamination by aluminium and consequent issues of child health persists. Samples of ready-made milks and powders used to make milks were prepared by microwave digestion of acid/peroxide mixtures and their aluminium content determined by THGA. The concentration of aluminium in ready-made milks varied from ca 176 to 700 μg/L. The latter concentration was for a milk for preterm infants. The aluminium content of powders used to make milks varied from ca 2.4 to 4.3 μg/g. The latter content was for a soya-based formula and equated to a ready-to-drink milk concentration of 629 μg/L. Using the manufacturer's own guidelines of formula consumption the average daily ingestion of aluminium from infant formulas for a child of 6 months varied from ca 200 to 600 μg of aluminium. Generally ingestion was higher from powdered as compared to ready-made formulas. The aluminium content of a range of well known brands of infant formulas remains high and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies. Recent research demonstrating the vulnerability of infants to early exposure to aluminium serves to highlight an urgent need to reduce the aluminium content of infant formulas to as low a level as is practically possible.

  8. Preparation of SiC based Aluminium metal matrix nano composites by high intensity ultrasonic cavitation process and evaluation of mechanical and tribological properties

    NASA Astrophysics Data System (ADS)

    Murthy, N. V.; Prasad Reddy, A.; Selvaraj, N.; Rao, C. S. P.

    2016-09-01

    Request augments on a worldwide scale for the new materials. The metal matrix nano composites can be used in numerous applications of helicopter structural parts, gas turbine exit guide vane's, space shuttle, and other structural applications. The key mailman to ameliorate performance of composite matrix in aluminium alloy metal reinforces nano particles in the matrix of alloy uniformly, which ameliorates composite properties without affecting limit of ductility. The ultrasonic assisted stir casting helped agitation was successfully used to fabricate Al 2219 metal matrix of alloy reinforced with (0.5, 1, 1.5 and 2) wt.% of nano silicon carbide (SiC) particles of different sizes 50nm and 150nm. The micrographs of scanning electron microscopy of nano composite were investigated it reveals that the uniform dispersion of nano particles silicon carbide in aluminium alloy 2219 matrix and with the low porosity. How the specific wear rate was vary with increasing weight percentage of nano particles at constant load and speed as shown in results and discussions. And the mechanical properties showed that the ultimate tensile strength and hardness of metal matrix nano composite AA 2219 / nano SiC of 50nm and 150nm lean to augment with increase weight percentage of silicon carbide content in the matrix alloy.

  9. Further Precipitation Reactions Associated with Beta’ (Al3Zr) Particles in Al-Li-Cu-Mg-Zr Alloys

    DTIC Science & Technology

    1988-12-01

    Gregson 8’ precipitation in Al-Li-Mg-Cu-Zr alloys. H.M. Flower J. Mater. Sci. Lett., 3, 829 (1984) 5 P.L. Makin On the ageing of an aluminium-lithium...Technol., 2, 349 (1986) 8 H.M. Flower The effect of composition and heat treatment upon the et al microstructure/property relationships in Al-Li-Cu-Mg...1119 REFERENCES concluded) No. Author Title, etc 10 P.J. Gregon Microstructural control of toughness in aluminium- H.M. Flower lithium alloys. Acta

  10. Oxidation behaviors of the aluminide coated TZM alloy via pack cementation

    NASA Astrophysics Data System (ADS)

    Park, J.; Kim, J. M.; Lee, S.; Park, J. S.

    2014-12-01

    TZM is a traditional alloy for high temperature applications, in which (Ti, Zr)C particles are dispersed in a Mo matrix. However, due to easy formation of an oxide layer on the TZM alloy under ambient atmosphere, an oxidation protective coating is needed for any high temperature structural applications of TZM. In this study, aluminium pack cementation coatings have been carried out on TZM alloys, resulting in the formation of Al8Mo3 layer on the surface of TZM alloys. In order to examine the oxidation stability, the TZM alloy was exposed in an aerobic atmosphere. For the aluminide coated TZM alloys, an alumina layer was produced at the outer surface layer. The alminide coated TZM alloys showed excellent oxidation resistance. The coating layer kinetics and the corresponding oxidation stability are also discussed in terms of microstructural observations.

  11. Speciation analysis of aluminium and aluminium fluoride complexes by HPIC-UVVIS.

    PubMed

    Frankowski, Marcin; Zioła-Frankowska, Anetta

    2010-10-15

    The study presents a new analytical method for speciation analysis in fractionation of aluminium fluoride complexes and free Al(3+) in soil samples. Aluminium speciation was studied in model solutions and soil extract samples by means of high performance ion chromatography (HPIC) with UV-VIS detection using post-column reaction with tiron for the separation and detection of aluminium fluoride complex and Al(3+) forms during one analysis. The paper presents particular stages of the chromatographic process optimization involving selecting the appropriate eluent strength, type of elution or concentration and quantity of derivatization reagent. HPIC was performed on a bifunctional analytical column Dionex IonPac CS5A. The use of gradient elution and the eluents A: 1M NH(4)Cl and B: water acidified to pH of eluent phase, enabled full separation of fluoride aluminium forms as AlF(2)(+), AlF(3)(0), AlF(4)(-) (first signal), AlF(2+) (second signal) and form Al(3+) in a single analytical procedure. The proposed new method HPIC-UVVIS was applied successfully in the quantitative and qualitative analysis of soil samples. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Aluminium salt slag characterization and utilization--a review.

    PubMed

    Tsakiridis, P E

    2012-05-30

    Aluminium salt slag (also known as aluminium salt cake), which is produced by the secondary aluminium industry, is formed during aluminium scrap/dross melting and contains 15-30% aluminium oxide, 30-55% sodium chloride, 15-30% potassium chloride, 5-7% metallic aluminium and impurities (carbides, nitrides, sulphides and phosphides). Depending on the raw mix the amount of salt slag produced per tonne of secondary aluminium ranges from 200 to 500 kg. As salt slag has been classified as toxic and hazardous waste, it should be managed in compliance with the current legislation. Its landfill disposal is forbidden in most of the European countries and it should be recycled and processed in a proper way by taking the environmental impact into consideration. This paper presents a review of the aluminium salt slag chemical and mineralogical characteristics, as well as various processes for metal recovery, recycling of sodium and potassium chlorides content back to the smelting process and preparation of value added products from the final non metallic residue. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Aluminium removal from water after defluoridation with the electrocoagulation process.

    PubMed

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  14. Aluminium in Bone from Patients with Renal Failure

    PubMed Central

    Parsons, Victor; Davies, Christine; Goode, Clifford; Ogg, Chisholm; Siddiqui, J.

    1971-01-01

    Some samples of bone from patients with renal failure contained more aluminium than others, and the concentration tended to be highest in patients who had been uraemic or on dialysis longest. The significance of the association of raised concentrations of aluminium in bone with renal failure is discussed. PMID:5123910

  15. Effect of Weight Percentage and Cutting Parameter on Surface Finish of SiC Reinforced Aluminium Composite

    NASA Astrophysics Data System (ADS)

    Kadadevaramath, R. S.; Kotresh, M. C.; Srinivasan, D.

    2016-09-01

    In the present work, aluminium alloy of series 1100 is selected as a matrix material and SiC of 45 microns as reinforcement. The composites are synthesized by 2 stage stir casting route, by varying a weight % of reinforcement from 6 % and 10%. The surface roughness of prepared composite were examined after plain turning operation. The machining parameters like speed, feed, DOC, SiC Wt. % are varied at 3 different levels. In order to minimize the time, cost and material a taguchi L9 orthogonal array was used for experiment. From the studies it was observed that the roughness value will increase with the increasing in reinforcement percentage.

  16. Casting alloys.

    PubMed

    Wataha, John C; Messer, Regina L

    2004-04-01

    Although the role of dental casting alloys has changed in recent years with the development of improved all-ceramic materials and resin-based composites, alloys will likely continue to be critical assets in the treatment of missing and severely damaged teeth. Alloy shave physical, chemical, and biologic properties that exceed other classes of materials. The selection of the appropriate dental casting alloy is paramount to the long-term success of dental prostheses,and the selection process has become complex with the development of many new alloys. However, this selection process is manageable if the practitioner focuses on the appropriate physical and biologic properties, such as tensile strength, modulus of elasticity,corrosion, and biocompatibility, and avoids dwelling on the less important properties of alloy color and short-term cost. The appropriate selection of an alloy helps to ensure a longer-lasting restoration and better oral health for the patient.

  17. Aluminium Electroplating on Steel from a Fused Bromide Electrolyte

    SciTech Connect

    Prabhat Tripathy; Laura Wurth; Eric Dufek; Toni Y. Gutknecht; Natalie Gese; Paula Hahn; Steven Frank; Guy Fredrickson; J Stephen Herring

    2014-08-01

    A quaternary bromide bath (LiBr-KBr-CsBr-AlBr3) was used to electro-coat aluminium on steel substrates. The electrolyte was prepared by the addition of AlBr3 into the eutectic LiBr-KBr-CsBr melt. A smooth, thick, adherent and shiny aluminium coating could be obtained with 80 wt.% AlBr3 in the ternary melt. The SEM photographs of the coated surfaces suggest the formation of thick and dense coatings with good aluminium coverage. Both salt immersion and open circuit potential measurement suggest that the coatings did display good corrosion-resistance behavior. Annealing of the coated surfaces, prior to corrosion tests, suggested the robustness of the metallic aluminium coating in preventing the corrosion of the steel surfaces. Studies also indicated that the quaternary bromide plating bath can potentially provide a better aluminium coating on both ferrous and non-ferrous metals, including complex surfaces/geometries.

  18. Usage of Neural Network to Predict Aluminium Oxide Layer Thickness

    PubMed Central

    Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

    2015-01-01

    This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A·dm−2 and 3 A·dm−2 for creating aluminium oxide layer. PMID:25922850

  19. Galvanised steel to aluminium joining by laser and GTAW processes

    SciTech Connect

    Sierra, G.; Peyre, P.; Deschaux Beaume, F. Stuart, D.; Fras, G.

    2008-12-15

    A new means of assembling galvanised steel to aluminium involving a reaction between solid steel and liquid aluminium was developed, using laser and gas tungsten arc welding (GTAW) processes. A direct aluminium melting strategy was investigated with the laser process, whereas an aluminium-induced melting by steel heating and heat conduction through the steel was carried out with the GTAW process. The interfaces generated during the interaction were mainly composed of a 2-40 {mu}m thick intermetallic reaction layers. The linear strength of the assemblies can be as high as 250 N/mm and 190 N/mm for the assemblies produced respectively by laser and GTAW processes. The corresponding failures were located in the fusion zone of aluminium (laser assemblies), or in the reaction layer (GTAW assemblies)

  20. Multilayer roll bonded aluminium foil: processing, microstructure and flow stress

    SciTech Connect

    Barlow, C.Y.; Nielsen, P.; Hansen, N

    2004-08-02

    Bulk aluminium has been produced by warm-rolling followed by cold-rolling of commercial purity (99% purity) aluminium foil. The bonding appeared perfect from observation with the naked eye, light and transmission electron microscopy. By comparison with bulk aluminium of similar purity (AA1200) rolled to a similar strain (90%RA), the roll-bonded metal showed a much higher density of high-angle grain boundaries, similar strength and improved thermal stability. This study has implications for a number of applications in relation to the processing of aluminium. Roll bonding is of interest as a method for grain size refinement; oxide-containing materials have increased strength, enhanced work-hardening behaviour, and exhibit alterations in recrystallisation behaviour. The behaviour of the hard oxide film is of interest in aluminium processing, and has been investigated by characterising the size and distribution of oxide particles in the roll-bonded samples.

  1. Amélioration des performances du procédé de soudage TIG sur un acier au carbone et un alliage d'aluminium par dépôt de silice

    NASA Astrophysics Data System (ADS)

    Sire, Stéphane; Marya, Surendar

    This Note presents ways to improve the weld penetration potential of TIG process by optimising silica application around the joints in a plain carbon steel and an aluminium alloy 5086. Whereas for plain carbon steels, full coverage of joint improves penetration, the presence of a blank zone around the joint in the flux coating on aluminium 5086 using AC-TIG seems to be the best solution for cosmetic and deep welds. To cite this article: S. Sire, S. Marya, C. R. Mecanique 330 (2002) 83-89.

  2. Experimental fatigue curves for aluminium brazed areas

    NASA Astrophysics Data System (ADS)

    Dimitescu, A.; Babiş, C.; Niţoi, D. F.; Radu, C.

    2017-08-01

    An important factor for the quality of joints is the brazed area. The fatigue check occupies a major position among many test procedures and methods, especially by the joining technologies. The results of processing the fatigue data experiments for aluminium brazed samples are used to find the regression function and the response surface methodology. The fatigue process of mechanical components under service loading is stochastic in nature. The prediction of time-dependent fatigue reliability is critical for the design and maintenance planning of many structural components.

  3. Alumina Concentration Gradients in Aluminium Reduction Cells

    NASA Astrophysics Data System (ADS)

    Lavoie, Pascal; Taylor, Mark P.

    The length of aluminium electrolysis cells have constantly increased over the last decades. The drive to increase productivity resulted in the need to feed and dissolve more alumina in less electrolyte. There is mounting evidence that these two trends are pushing the electrolysis cells above their capability to maintain alumina concentration, through time and space, at levels preventing both conventional and non-propagating anode effects. Alumina concentration gradient measurements were performed within large industrial cells and showed that large gradients occurred between locations in cells.

  4. Scanning and transmission electron microscopy study of the microstructural changes occurring in aluminium matrix composites reinforced with SiC particles during casting and welding: interface reactions

    PubMed

    Urena; Gomez De Salazar JM; Gil; Escalera; Baldonedo

    1999-11-01

    Processing of aluminium matrix composites (AMCs), especially those constituted by a reactive system such as Al-SiC, presents great difficulties which limit their potential applications. The interface reactivity between SiC and molten Al generates an aluminium carbide which degrades the composite properties. Scanning and transmission electron microscopes equipped with energy-dispersive X-ray spectroscopes are essential tools for determining the structure and chemistry of the Al-SiC interfaces in AMCs and changes occurring during casting and arc welding. In the present work, an aluminium-copper alloy (AA2014) reinforced with three different percentages of SiC particles was subjected to controlled remelting tests, at temperatures in the range 750-900 degrees C for 10 and 30 min. Arc welding tests using a tungsten intert gas with power inputs in the range 850-2000 W were also carried out. The results of these studies showed that during remelting there is preferential SiC particle consumption with formation of Al4C3 by interface reaction between the solid SiC particle and the molten aluminium matrix. The formation of Al4C3 by the same mechanism has also been detected in molten pools of arc welded composites. However, in this case there was formation of an almost continuous layer of Al4C3, which protects the particle against further consumption, and formation of aciculate aluminium carbide on the top weld. Both are formed by fusion and dissolution of the SiC in molten aluminium followed by reaction and precipitation of the Al4C3 during cooling.

  5. Production and Compressive Characterization of Aluminium MMC Foam Manufactured Using Dual Foaming Agent

    NASA Astrophysics Data System (ADS)

    Haidar, S.; Ansary, S.; Rahman, A.

    2016-02-01

    Aluminium foams, produced by melting Aluminium alloy (LM6) containing blowing agent(s) and vigorous stirring. TiH2 is a known agent for this. As TiH2 begins to decompose into Ti and gaseous H2 when heated above about 465°C, large volumes of hydrogen gas are rapidly produced, creating bubbles that leads to a closed cell foam. A novel Strategy to enhance the mechanical properties of Al-MMC foams is discussed here, and it is demonstrated that titanium hydride (TiH2) in the form of 10-15 μm diameter particles can be pre-treated by selective oxidation to produce more uniform foams having better compressive properties (yield strength and energy absorption). It is found that the mechanical properties of the foams and the uniformity of cell size distribution is improved when the foam is blown with an optimized mixture of CaCO3 and pretreated TiH2. In order to define the relationship of mechanical properties with relative density of this material, correlations which uniquely defines the compressive behaviour of this modified Al- MMC foam has been developed.

  6. Investigation and in situ removal of spatter generated during laser ablation of aluminium composites

    NASA Astrophysics Data System (ADS)

    Popescu, A. C.; Delval, C.; Shadman, S.; Leparoux, M.

    2016-08-01

    Spatter generated during laser irradiation of an aluminium alloy nanocomposite (AlMg5 reinforced with Al2O3 nanoparticles) was monitored by high speed imaging. Droplets trajectory and speed were assessed by computerized image analysis. The effects of laser peak power and laser focusing on the plume expansion and expulsed droplet speeds were studied in air or under argon flow. It was found that the velocity of visible droplets expulsed laterally or at the end of the plume emission from the metal surface was not dependent on the plasma plume speed. The neighbouring area of irradiation sites was studied by optical and scanning electron microscopy. Droplets deposited on the surface were classified according to their size and counted using a digital image processing software. It was observed that the number of droplets on surface was 1.5-3 times higher when the laser beam was focused in depth as compared to focused beams, even though the populations average diameter were comparable. Three methods were selected for removing droplets in situ, during plume expansion: an argon gas jet crossing the plasma plume, a fused silica plate collector transparent to the laser wavelength placed parallel to the irradiated surface and a mask placed onto the aluminium composite surface. The argon gas jet was efficient only for low power irradiation conditions, the fused silica plate failed in all tested conditions and the mask was successful for all irradiation regimes.

  7. A separation method to overcome the interference of aluminium on zinc determination by inductively coupled plasma atomic emission spectroscopy

    NASA Astrophysics Data System (ADS)

    de Jesus, Djane S.; das Graças Korn, Maria; Ferreira, Sérgio L. C.; Carvalho, Marcelo S.

    2000-04-01

    The use of polyurethane foam (PUF) to separate zinc from large amounts of aluminium and its determination by inductively coupled plasma atomic emission spectroscopy technique (ICP-AES) in aluminium matrices is described. The proposed method is based on the solid-phase extraction of the zinc(II) cation as a thiocyanate complex. Parameters such as effect of pH on zinc sorption, zinc desorption from the foam and analytical features of the procedure were studied. Results showed that the zinc(II) cation within the range from 0.02 to 65.0 μg in 0.2 mol l -1 thiocyanate solution and pH range from 1.0 to 4.0, could be quantitatively extracted by 0.1 g of PUF. The precision of the method was calculated as the relative standard deviation from a series of seven measurements. It was 3.9% for 1.0 μg of zinc in a volume solution of 50 ml. The proposed procedure was used for zinc determination in both aluminium alloys and salts with zinc concentration in the range from 50 to 300 μg g -1. A standard addition technique was used and achieved results showing that this procedure has good accuracy and precision.

  8. Aluminium uptake and excretion in potroom workers of a new primary aluminium smelter during the construction stage.

    PubMed

    Röllin, H B; Theodorou, P; Nogueir, C M; Levin, J

    2001-12-01

    The aim of this study was to define bio-accumulation and excretion patterns of aluminium in newly employed potroom workers as well as changes in ambient aluminium levels in the potrooms of a modern aluminium smelter during the plant construction stage and one year into full production. A study was carried out on 115 newly employed volunteer potroom workers at various intervals, over a total period of 36 months. Before commencement of employment a structured questionnaire was completed by all study participants and the first collection of blood and urine specimens took place. As none of the subjects had ever worked in the aluminium industry before, they also served as their own controls. Atomic absorption spectroscopy was used to measure the aluminium content in the biological fluids and the content of the metal in the ambient air of the potrooms. Significantly, the study found an early and marked biological response to inhalation of very low levels of airborne aluminium. After only 12 months, the mean concentration of aluminium in serum had almost doubled; thereafter it levelled off. A mixed model analysis did not find any differences in the concentrations of aluminium in the serum of the subjects since the variation between subjects at any given time was much smaller than the variation within subjects. This may be an indication of the pronounced effect of aluminium inhalation on the kinetics of this metal in the human body. Furthermore, urinary excretion of aluminium by the potroom workers showed a linear increase reaching a concentration of only 49 microg l(-1) at the 36 month stage, suggesting a slow rate of elimination.

  9. Hearing conservation in the primary aluminium industry

    PubMed Central

    Frisch, N.; Dixon-Ernst, C.; Chesson, B. J.; Cullen, M. R.

    2016-01-01

    Background Noise-induced hearing loss has been an intractable problem for heavy industry. Aims To report our experience in reducing the incidence of age-corrected confirmed 10 dB hearing shifts (averaged over 2, 3 and 4kHz) in employees in the primary aluminium industry in Australia over the period 2006–13. Methods We analysed annual audiometric data to determine the number of permanent hearing shifts that occurred in employees in two bauxite mines, three alumina refineries and two aluminium smelters. Annual hearing shift rates were calculated based on the number of employees tested per year. Hearing conservation initiatives undertaken during the study period are described. An assessment of similar exposure group noise exposures was also undertaken to determine the magnitude of noise exposure reduction during the study period. Results Across all operations, hearing shift rates declined from 5.5% per year in 2006 to 1.3% per year in 2013 (P < 0.001). The decline in shift rates was greater in mines and refineries, where baseline shift rates were higher, than in smelter workers. Modest reductions in noise exposure occurred during the study period. Conclusions We observed a substantial decline in hearing shift rates during the study period. We describe the hearing conservation initiatives that were collectively associated with this decline. We suspect these initiatives could be deployed relatively easily and at modest cost in other industries with noise-exposed employees. PMID:26470945

  10. Hearing conservation in the primary aluminium industry.

    PubMed

    Donoghue, A M; Frisch, N; Dixon-Ernst, C; Chesson, B J; Cullen, M R

    2016-04-01

    Noise-induced hearing loss has been an intractable problem for heavy industry. To report our experience in reducing the incidence of age-corrected confirmed 10 dB hearing shifts (averaged over 2, 3 and 4 kHz) in employees in the primary aluminium industry in Australia over the period 2006-13. We analysed annual audiometric data to determine the number of permanent hearing shifts that occurred in employees in two bauxite mines, three alumina refineries and two aluminium smelters. Annual hearing shift rates were calculated based on the number of employees tested per year. Hearing conservation initiatives undertaken during the study period are described. An assessment of similar exposure group noise exposures was also undertaken to determine the magnitude of noise exposure reduction during the study period. Across all operations, hearing shift rates declined from 5.5% per year in 2006 to 1.3% per year in 2013 (P < 0.001). The decline in shift rates was greater in mines and refineries, where baseline shift rates were higher, than in smelter workers. Modest reductions in noise exposure occurred during the study period. We observed a substantial decline in hearing shift rates during the study period. We describe the hearing conservation initiatives that were collectively associated with this decline. We suspect these initiatives could be deployed relatively easily and at modest cost in other industries with noise-exposed employees. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine.

  11. Effect of hydrogen on the integrity of aluminium-oxide interface at elevated temperatures.

    PubMed

    Li, Meng; Xie, De-Gang; Ma, Evan; Li, Ju; Zhang, Xi-Xiang; Shan, Zhi-Wei

    2017-02-20

    Hydrogen can facilitate the detachment of protective oxide layer off metals and alloys. The degradation is usually exacerbated at elevated temperatures in many industrial applications; however, its origin remains poorly understood. Here by heating hydrogenated aluminium inside an environmental transmission electron microscope, we show that hydrogen exposure of just a few minutes can greatly degrade the high temperature integrity of metal-oxide interface. Moreover, there exists a critical temperature of ∼150 °C, above which the growth of cavities at the metal-oxide interface reverses to shrinkage, followed by the formation of a few giant cavities. Vacancy supersaturation, activation of a long-range diffusion pathway along the detached interface and the dissociation of hydrogen-vacancy complexes are critical factors affecting this behaviour. These results enrich the understanding of hydrogen-induced interfacial failure at elevated temperatures.

  12. Press hardening of alternative high strength aluminium and ultra-high strength steels

    NASA Astrophysics Data System (ADS)

    Mendiguren, Joseba; Ortubay, Rafael; Agirretxe, Xabier; Galdos, Lander; de Argandoña, Eneko Sáenz

    2016-10-01

    The boron steel press hardening process takes more and more importance on the body in white structure in the last decade. In this work, the advantages of using alternative alloys on the press hardening process is analysed. In particular, the press hardening of AA7075 high strength aluminium and CP800 complex phase ultra-high strength steel is analysed. The objective is to analyse the potential decrease on springback while taking into account the strength change associated with the microstructural modification carried out during the press hardening process. The results show a clear improvement of the final springback in both cases. Regarding the final mechanical properties, an important decrease has been measured in the AA7075 due to the process while an important increase has been found in the CP800 material.

  13. Cast aluminium single crystals cross the threshold from bulk to size-dependent stochastic plasticity

    NASA Astrophysics Data System (ADS)

    Krebs, J.; Rao, S. I.; Verheyden, S.; Miko, C.; Goodall, R.; Curtin, W. A.; Mortensen, A.

    2017-07-01

    Metals are known to exhibit mechanical behaviour at the nanoscale different to bulk samples. This transition typically initiates at the micrometre scale, yet existing techniques to produce micrometre-sized samples often introduce artefacts that can influence deformation mechanisms. Here, we demonstrate the casting of micrometre-scale aluminium single-crystal wires by infiltration of a salt mould. Samples have millimetre lengths, smooth surfaces, a range of crystallographic orientations, and a diameter D as small as 6 μm. The wires deform in bursts, at a stress that increases with decreasing D. Bursts greater than 200 nm account for roughly 50% of wire deformation and have exponentially distributed intensities. Dislocation dynamics simulations show that single-arm sources that produce large displacement bursts halted by stochastic cross-slip and lock formation explain microcast wire behaviour. This microcasting technique may be extended to several other metals or alloys and offers the possibility of exploring mechanical behaviour spanning the micrometre scale.

  14. Numerical and experimental analysis of cold stretching of aluminium sheets using an instrumented bench

    NASA Astrophysics Data System (ADS)

    El Gueder, Jawhar; Giraud, Eliane; Zhao, Nan; Dal Santo, Philippe

    2016-10-01

    Cold stretching is a forming process meanly used in aeronautic industry to obtain deep drawing parts from thin sheets. It's not very easy to characterize the process using industrial machines, due to production constraints and complexity of their structures. In this study, an instrumented bench is developed to analyse the forming of double curvature panels in 5754H111 Aluminium alloys. A numerical tool using ABAQUS software is developed to predict the behaviour of thin sheets during the stretching process and also to estimate the residual mechanical field in the formed shapes. The bench is calibrated by comparing experiments and numerical results in terms of deformed shape, in-plane strain levels and thickness evolution.

  15. Effect of hydrogen on the integrity of aluminium-oxide interface at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Li, Meng; Xie, De-Gang; Ma, Evan; Li, Ju; Zhang, Xi-Xiang; Shan, Zhi-Wei

    2017-02-01

    Hydrogen can facilitate the detachment of protective oxide layer off metals and alloys. The degradation is usually exacerbated at elevated temperatures in many industrial applications; however, its origin remains poorly understood. Here by heating hydrogenated aluminium inside an environmental transmission electron microscope, we show that hydrogen exposure of just a few minutes can greatly degrade the high temperature integrity of metal-oxide interface. Moreover, there exists a critical temperature of ~150 °C, above which the growth of cavities at the metal-oxide interface reverses to shrinkage, followed by the formation of a few giant cavities. Vacancy supersaturation, activation of a long-range diffusion pathway along the detached interface and the dissociation of hydrogen-vacancy complexes are critical factors affecting this behaviour. These results enrich the understanding of hydrogen-induced interfacial failure at elevated temperatures.

  16. VANADIUM ALLOYS

    DOEpatents

    Smith, K.F.; Van Thyne, R.J.

    1959-05-12

    This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

  17. BRAZING ALLOYS

    DOEpatents

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

    1963-02-26

    A brazing alloy which, in the molten state, is characterized by excellent wettability and flowability, said alloy being capable of forming a corrosion resistant brazed joint wherein at least one component of said joint is graphite and the other component is a corrosion resistant refractory metal, said alloy consisting essentially of 20 to 50 per cent by weight of gold, 20 to 50 per cent by weight of nickel, and 15 to 45 per cent by weight of molybdenum. (AEC)

  18. Development of corrosion resistant aluminum heat exchanger, Part 1: Development of new aluminum alloy sheets for sacrificial anode

    SciTech Connect

    Hagiwara, M.; Baba, Y.; Tanabe, Z.; Miura, T.; Hasegawa, Y.; Iijima, K.

    1986-01-01

    The sacrificial anodic effect of Al-Zn alloy reduced markedly in aluminium heat exchanger as car air conditioner manufactured by vacuum brazing conventionally used, as zinc elements preferentially evaporate in vacuum-heating. It was found that Al-Sn alloy had superior electrochemical characteristics than Al-Zn alloy (AA7072) as the sacrificial anodic material used in vacuum brazing. According to many experimental results, the new brazing sheet-fin with Al-Mn-Sn alloy core metal has been developed. This fin has favorable formability and prominent sacrificial anodic effect. Therefore, this fin is excellent material for car air conditioner manufactured by vacuum brazing.

  19. Unexpected loss of contact allergy to aluminium induced by vaccine.

    PubMed

    Gente Lidholm, Anette; Bergfors, Elisabet; Inerot, Annica; Blomgren, Ulla; Gillstedt, Martin; Trollfors, Birger

    2013-05-01

    In studies in Gothenburg, Sweden, in the 1990s of an aluminium hydroxide-adsorbed pertussis toxoid vaccine, 745 of ~76 000 vaccinated children developed long-lasting itchy subcutaneous nodules at the vaccination site. Of 495 children with itchy nodules patch tested for aluminium allergy, 376 (76%) were positive. To study the prognosis of the vaccine-induced aluminium allergy. Two hundred and forty-one children with demonstrated aluminium allergy in the previous study were patch tested again 5-9 years after the initial test, with the same procedure as used previously. Contact allergy to aluminium was no longer demonstrable in 186 of the retested 241 children (77%). A negative test result was more common in children who no longer had itching at the vaccination site; it was also related to the age of the child, the time after the first aluminium-adsorbed vaccine dose, and the strength of the reaction in the first test. Patch test reactivity to aluminium seems to disappear or weaken with time. © 2013 John Wiley & Sons A/S.

  20. Does allergen-specific immunotherapy induce contact allergy to aluminium?

    PubMed

    Netterlid, Eva; Hindsén, Monica; Siemund, Ingrid; Björk, Jonas; Werner, Sonja; Jacobsson, Helene; Güner, Nuray; Bruze, Magnus

    2013-01-01

    Persistent, itching nodules have been reported to appear at the injection site after allergen-specific immuno-therapy with aluminium-precipitated antigen extract, occasionally in conjunction with contact allergy to aluminium. This study aimed to quantify the development of contact allergy to aluminium during allergen-specific immunotherapy. A randomized, controlled, single-blind multicentre study of children and adults entering allergen-specific immunotherapy was performed using questionnaires and patch-testing. A total of 205 individuals completed the study. In the 3 study groups all subjects tested negative to aluminium before allergen-specific immunotherapy and 4 tested positive after therapy. In the control group 4 participants tested positive to aluminium. Six out of 8 who tested positive also had atopic dermatitis. Positive test results were found in 5/78 children and 3/127 adults. Allergen-specific immunotherapy was not shown to be a risk factor for contact allergy to aluminium. Among those who did develop aluminium allergy, children and those with atopic dermatitis were more highly represented.

  1. The varied functions of aluminium-activated malate transporters-much more than aluminium resistance.

    PubMed

    Palmer, Antony J; Baker, Alison; Muench, Stephen P

    2016-06-15

    The ALMT (aluminium-activated malate transporter) family comprises a functionally diverse but structurally similar group of ion channels. They are found ubiquitously in plant species, expressed throughout different tissues, and located in either the plasma membrane or tonoplast. The first family member identified was TaALMT1, discovered in wheat root tips, which was found to be involved in aluminium resistance by means of malate exudation into the soil. However, since this discovery other family members have been shown to have many other functions such as roles in stomatal opening, general anionic homoeostasis, and in economically valuable traits such as fruit flavour. Recent evidence has also shown that ALMT proteins can act as key molecular actors in GABA (γ-aminobutyric acid) signalling, the first evidence that GABA can act as a signal transducer in plants. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  2. The varied functions of aluminium-activated malate transporters–much more than aluminium resistance

    PubMed Central

    Palmer, Antony J.; Baker, Alison; Muench, Stephen P.

    2016-01-01

    The ALMT (aluminium-activated malate transporter) family comprises a functionally diverse but structurally similar group of ion channels. They are found ubiquitously in plant species, expressed throughout different tissues, and located in either the plasma membrane or tonoplast. The first family member identified was TaALMT1, discovered in wheat root tips, which was found to be involved in aluminium resistance by means of malate exudation into the soil. However, since this discovery other family members have been shown to have many other functions such as roles in stomatal opening, general anionic homoeostasis, and in economically valuable traits such as fruit flavour. Recent evidence has also shown that ALMT proteins can act as key molecular actors in GABA (γ-aminobutyric acid) signalling, the first evidence that GABA can act as a signal transducer in plants. PMID:27284052

  3. A Study of Al-Zn-Sn Alloy Sacrificial Anode Cathodic Protection Requirements for Structure Used In Seawater

    SciTech Connect

    Kamarudin, Siti Radiah Mohd; Daud, Muhamad; Sattar, Shariff; Daud, Abd. Razak

    2010-01-05

    The corrosion of aluminium (Al) alloys in seawater was investigated using potentiodynamic technique, complemented by Scanning Electron Microscopy (SEM), EDAX and XRD. SEM was used out to characterize the corroded surface and to observe the extent of corrosion attack on the Al alloys tested in seawater. EDAX analysis was used to identify elements present on the specimen surface. Where else XRD was to identify phase appearance. The results indicate that zinc (Zn), stanum (Sn) and copper (Cu) as alloying elements enhance corrosion behaviour of the aluminium in seawater by shifting the potential to a more negative value. In the presence of those elements, the Al alloys becomes more active, having potential of more than -1.0 V{sub SCE} and showed active corrosion behaviour.

  4. Aluminium migration into beverages: are dented cans safe?

    PubMed

    Veríssimo, Marta I S; Gomes, M Teresa S R

    2008-11-01

    Aluminium (Al) migration from cans to beer and tea was studied along time. Analyses of Al in the canned drinks were performed till the sell-by date, and, in seven months, aluminium migration was found to increase 0.14 mg L(-1) in beer, and 0.6 mg L(-1) in tea. This study included dented cans from which aluminium migration into tea was found to be particularly severe. Al concentration in dented canned tea increased 9.6 mg L(-1) in seven months.

  5. Recurrent sterile abscesses following aluminium adjuvant-containing vaccines.

    PubMed

    Klein, Nicola P; Edwards, Kathryn M; Sparks, Robert C; Dekker, Cornelia L

    2009-01-01

    Abscess formation following immunisation is a previously reported complication, generally associated with microbial contamination of the vaccine. Less commonly, such abscesses have been sterile. Here we describe two children evaluated in the Center for Disease Control and Prevention (CDC)-funded Clinical Immunization Safety Assessment (CISA) network who developed recurrent sterile abscesses after administration of vaccines containing aluminium adjuvant, either individually or in combination. Although the abscesses healed without sequelae, these occurrences support an association between receipt of aluminium adjuvant and sterile abscesses in susceptible patients. For patients with similar symptoms, clinicians may wish to choose a vaccine formulation containing the least amount of aluminium adjuvant.

  6. Renal excretion of aluminium in the rat: effect of citrate infusion.

    PubMed

    Lote, C J; Willmott, K; Wood, J A; Thewles, A; Freeman, M

    1995-12-01

    When aluminium is administered intravenously to rats, the speciation of the aluminium has a major effect on its renal excretion. Aluminium administered as citrate is much more effectively excreted than that administered as chloride or sulphate. This suggests that citrate could be therapeutically useful in patients who have been exposed to aluminium. Accordingly, we have performed two series of experiments in rats, in which a citrate infusion (intravenous), was begun either immediately after, or one hour after, the administration of an intravenous aluminium sulphate bolus. Both protocols led to markedly enhanced aluminium excretion compared to controls in which only 0.7% NaCl was infused. The enhancement of aluminium excretion was 783% if citrate infusion was begun immediately after aluminium administration, and 335% if the citrate infusion began after an hour delay. The increased excretion was due to an increase in the freely filterable fraction of aluminium. In the control experiments, in which aluminium sulphate administration was followed by 0.7% NaCl infusion, aluminium was found to be deposited in the liver. Administration of citrate one hour after the aluminium bolus did not reduce this liver deposition. The results indicate that a fraction of the plasma aluminium is accessible to the citrate infused and can thereby be converted into a filterable form which can be excreted. It appears that, for maximum therapeutic effect, citrate should be infused as rapidly as possible after an aluminium load, to limit aluminium binding to ligands which allow it to enter cells.

  7. Microstructure Analysis on 6061 Aluminum Alloy after Casting and Diffuses Annealing Process

    NASA Astrophysics Data System (ADS)

    Wang, H. Q.; Sun, W. L.; Xing, Y. Q.

    One factory using semi-continuous casting process produce the ф200×6000 mm 6061 aluminium alloy barstock, and then rotary forged for car wheels. 6061 distorting aluminium alloy is an forged aluminum alloy, and mainly containing Mg, Si, Cu and other alloying elements. The main strengthening phase is Mg2Si, and also has few phase of (FeMn) 3Si2Al15. In order to eliminate the segregation and separation which present in the crystal boundary, and make the distortion to be uniform, and does not present ear and fracture defects after the forging. So the 6061 distorting aluminium alloy adopt the diffusion annealing heat treatment before the forging process.According to the current conditions, we use the diffusion annealing which have the different heating temperature and different holding time.The best process we can obtain from the test which can improve the production efficiency and reduce the material waste, improve the mechanical properties, and eliminate the overheated film on the surface.Then,we using OM,SEM and EDS to analyse the microstructure and the chemical composition of compound between the surface and centre. The result shows that the amount of segregation were different in the surface and in the center, and the different diffusion annealing can cause the phase change in the surface and the center.

  8. Aluminium and iron air pollution near an iron casting and aluminium foundry in Turin district (Italy).

    PubMed

    Polizzi, Salvatore; Ferrara, Mauro; Bugiani, Massimiliano; Barbero, Domenico; Baccolo, Tiziana

    2007-09-01

    This work reports the results of an environmental survey carried out in an industrial area in the Province of Turin: its main aim is to assess the levels of iron and aluminium in the outside air during the period from July to September to assess the influence of industrial activity (a cast-iron and aluminium foundry) which is interrupted during the month of August, on the level of metals present in the air. Conducting the analysis during this period of time made it possible to avoid the confounding effect of pollution due to domestic central heating. The measurements were taken from nine areas at different distances from the foundry in the area and according to the direction of the prevailing winds, as deduced from the historical data. The results of this survey show a statistically significant difference in iron and aluminium levels in the outside air in the geographic areas between the two main periods examined: during August (no foundry activity) v/s July-September (foundry activity). The values recorded are: Aluminium 0.4+/-0.45 microg/m(3) v/s 1.12+/-1.29 microg/m(3) (p<0.0001); Iron 0.95+/-0.56 microg/m(3) v/s 1.6+/-1.0 microg/m(3) (p<0.0001). There were no statistically significant differences between the nine sampling points from the point of view of the sampling sites, climate conditions and wind directions. We found no correlation with car traffic, in terms of the number of vehicles, and metals. The values of iron tended to be higher in the areas farther away from the foundry site in the areas located along the path of the prevailing winds.

  9. Assessment of refining effectiveness of self-prepared nano-(TiNb)C/(NbTi)/Al complex powder inoculation on A356 alloy

    NASA Astrophysics Data System (ADS)

    Qiao, Gui-ying; Wu, Da-yong; Wei, Teng-fei; Liao, Bo; Xiao, Fu-ren

    2017-07-01

    Inoculation plays an effective role to refine the microstructure of as-cast aluminium alloys, which strongly depend on the effectiveness of the inoculants. In this work, a new concept of nano-(TiNb)C/(NbTi)/Al complex powder as an inoculant for refining the as-cast aluminium alloys was proposed, and the nano-(TiNb)C/(NbTi)/Al complex powder was prepared by mechanical alloying (MA) method, furthermore, the refining effectiveness of inoculation on A356 alloy was investigated. Results show that the nano-(TiNb)C/(NbTi)/Al complex powder consists of three phases of α-Al, nano-(TiNb)C and (NbTi) solid solution. The nano-(TiNb)C/(NbTi)/Al complex powder as an inoculant have higher refining effectiveness as well as good recyclability on the microstructure of cast A356 alloy, and improve the mechanical properties, especially the ductility.

  10. Tuning the Hydrogen Storage in Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Er, Suleyman; de Wijs, Gilles A.; Brocks, Geert

    2011-03-01

    We investigate the hydrogen storage properties of promising magnesium alloys. Mg H2 (7.6 wt % H) would be a very useful storage material if the (de)hydrogenation kinetics can be improved and the desorption temperature is markedly lowered. Using first principles calculations, we show that hydrides of Mg-transition metal (TM) alloys adopt a structure that promotes faster (de)hydrogenation kinetics, as is also observed in experiment. Within the lightweight TMs, the most promising alloying element is titanium. Alloying Mg with Ti alone, however, is not sufficient to decrease the stability of the hydride phases, which is necessary to reduce the hydrogen desorption temperature. We find that adding aluminium or silicon markedly destabilizes Mg-Ti hydrides and stabilizes Mg-Ti alloys. Finally, we show that controlling the structure of Mg-Ti-Al(Si) system by growing it as multilayers, has a beneficial influence on the thermodynamic properties and makes it a stronger candidate for hydrogen storage.

  11. A quest for super dense aluminium

    NASA Astrophysics Data System (ADS)

    Fiquet, G.; Narayana, C.; Bellin, C.; Shukla, A.; Esteve, I.; Mezouar, N.

    2013-12-01

    The extreme pressure phase diagram of materials is important not only for understanding the interiors of planets or stars, but also for the fundamental understanding of the relation between crystal structure and electronic structure. Structural transitions induced by extreme pressure are governed by the deformation of valence electron charge density which bears the brunt of increasing compression while the relative volume occupied by the nearly incompressible ionic core electrons increases. At extreme pressures common materials are expected to transform into new dense phases with extremely compact atomic arrangements that may also have unusual physical properties. In this report, we present new experiments carried out on aluminium. A simple system like Al is not only important as a benchmark for theory, but can also be used as a standard for pressures in the TPa range and beyond which are targeted at new dynamic compression facilities such as the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in the US or Laser Mégajoule (LMJ) in Bordeaux in France. For aluminium, first principle calculations have consistently predicted a phase transition sequence from fcc to hcp and hcp to bcc in a pressure range below 0.5 TPa [Tambe et al., Phys. Rev. B 77, 172102, 2008]. The hcp phase was identified at 217 GPa in a recent experiment [Akahama et al., Phys. Rev. Lett. 96, 45505, 2006] but the detection of the predicted bcc phase has been hampered by the difficulty of routine static high pressure experiments beyond 350 GPa. Here, we report on the overcoming of this obstacle and the detection of all the structural phase transitions predicted in Al by achieving a pressure in excess of 500 GPa in the static regime in a diamond-anvil cell. In particular, using X-ray diffraction at the high-pressure beamline ID27 at the European Synchrotron Radiation Facility (ESRF), we find a bcc super-dense phase of aluminium at a pressure of 380 GPa. In this report

  12. PILOT EVALUATION OF VANADIUM ALLOYS.

    DTIC Science & Technology

    ARCS, SHEETS, ROLLING(METALLURGY), HIGH TEMPERATURE, SCIENTIFIC RESEARCH, COMPRESSIVE PROPERTIES, DUCTILITY, CREEP, OXIDATION, COATINGS , SILICIDES , HARDNESS, WELDING, EXTRUSION, TANTALUM ALLOYS, MOLYBDENUM ALLOYS....VANADIUM ALLOYS, * NIOBIUM ALLOYS, MECHANICAL PROPERTIES, MECHANICAL PROPERTIES, TITANIUM ALLOYS, ZIRCONIUM ALLOYS, CARBON ALLOYS, MELTING, ELECTRIC

  13. Microstructures and characteristics of solid state recycling aluminium chips AA6061/Al-SiC composites fabricated by cold compaction method

    NASA Astrophysics Data System (ADS)

    Kadir, Muhammad Irfan Ab; Mustapa, Mohammad Sukri; Ibrahim, Mohd Rasidi; Samsi, Mohd Arif; Mahdi, Ahmed Sahib

    2017-05-01

    Solid state recycling methods allow the production of high density aluminium alloy parts directly from aluminium scrap. Direct conversion approach of recycling of aluminium is relatively easy, less energy usage and environmental friendly. In this paper, AA6061 chips were recycled to fabricate SiC particle (2.5, 5 and 7.5 wt.%) and Al powder (10, 30 and 50 wt.%) reinforced AA6061 alloy matrix composites by the combination cold pressing techniques and sintering process. The effects of various composition of Al and SiC powder on the microstructure of the recycled AA6061/Al-SiC composites showed that the Al and SiC powders in samples were distributed non-homogeneously and randomly between the AA6061 chip regions. The density of sample AA6061/10Al powder gave the closest value to theoretical at 2.43 g/cm3 and decreases when more Al powder were added. The AA6061/10Al-7.5SiC sample showed the highest hardness at 61.0 Hv.

  14. The Tungsten Inert GAS (TIG) Process of Welding Aluminium in Microgravity: Technical and Economic Considerations

    NASA Astrophysics Data System (ADS)

    Ferretti, S.; Amadori, K.; Boccalatte, A.; Alessandrini, M.; Freddi, A.; Persiani, F.; Poli, G.

    2002-01-01

    The UNIBO team composed of students and professors of the University of Bologna along with technicians and engineers from Alenia Space Division and Siad Italargon Division, took part in the 3rd Student Parabolic Flight Campaign of the European Space Agency in 2000. It won the student competition and went on to take part in the Professional Parabolic Flight Campaign of May 2001. The experiment focused on "dendritic growth in aluminium alloy weldings", and investigated topics related to the welding process of aluminium in microgravity. The purpose of the research is to optimise the process and to define the areas of interest that could be improved by new conceptual designs. The team performed accurate tests in microgravity to determine which phenomena have the greatest impact on the quality of the weldings with respect to penetration, surface roughness and the microstructures that are formed during the solidification. Various parameters were considered in the economic-technical optimisation, such as the type of electrode and its tip angle. Ground and space tests have determined the optimum chemical composition of the electrodes to offer longest life while maintaining the shape of the point. Additionally, the power consumption has been optimised; this offers opportunities for promoting the product to the customer as well as being environmentally friendly. Tests performed on the Al-Li alloys showed a significant influence of some physical phenomena such as the Marangoni effect and thermal diffusion; predictions have been made on the basis of observations of the thermal flux seen in the stereophotos. Space transportation today is a key element in the construction of space stations and future planetary bases, because the volumes available for launch to space are directly related to the payload capacity of rockets or the Space Shuttle. The research performed gives engineers the opportunity to consider completely new concepts for designing structures for space applications

  15. A Versatile Method for Nanostructuring Metals, Alloys and Metal Based Composites

    NASA Astrophysics Data System (ADS)

    Gurau, G.; Gurau, C.; Bujoreanu, L. G.; Sampath, V.

    2017-06-01

    A new severe plastic deformation method based on High Pressure Torsion is described. The method patented as High Speed High Pressure Torsion (HSHPT) shows a wide scope and excellent adaptability assuring large plastic deformation degree on metals, alloys even on hard to deform or brittle alloys. The paper present results obtained on aluminium, magnesium, titan, iron and coper alloys. In addition capability of HSHPT to process metallic composites is described. OM SEM, TEM, DSC, RDX and HV investigation methods were employed to confirm fine and ultrafine structure.

  16. Nonswelling alloy

    DOEpatents

    Harkness, S.D.

    1975-12-23

    An aluminum alloy containing one weight percent copper has been found to be resistant to void formation and thus is useful in all nuclear applications which currently use aluminum or other aluminum alloys in reactor positions which are subjected to high neutron doses.

  17. URANIUM ALLOYS

    DOEpatents

    Seybolt, A.U.

    1958-04-15

    Uranium alloys containing from 0.1 to 10% by weight, but preferably at least 5%, of either zirconium, niobium, or molybdenum exhibit highly desirable nuclear and structural properties which may be improved by heating the alloy to about 900 d C for an extended period of time and then rapidly quenching it.

  18. ZIRCONIUM ALLOY

    DOEpatents

    Wilhelm, H.A.; Ames, D.P.

    1959-02-01

    A binary zirconiuin--antimony alloy is presented which is corrosion resistant and hard containing from 0.07% to 1.6% by weight of Sb. The alloys have good corrosion resistance and are useful in building equipment for the chemical industry.

  19. Telangiectasia in aluminium workers: a follow up.

    PubMed

    Thériault, G; Gingras, S; Provencher, S

    1984-08-01

    A five step investigation was carried out to gain a better understanding of the morbidity that accompanied the development of telangiectasia on aluminium workers and to find its cause. Fifty workers with multiple telangiectasia when matched with normal controls showed the same amount of illness except that evidence of ischaemia on the ECG was found in nine cases and one control. The cases did not show an excess of abnormal biochemical tests. The basic histopathological lesion affected the surrounding tissue rather than the vessels themselves. Working in the current environment and wearing masks seems to protect young workers from developing the lesions. The Soderberg and not the prebake process was associated with the lesions; the causative agent is probably a gas that contains both hydrocarbons and fluoride components emitted from the electrolytic reactors.

  20. Telangiectasia in aluminium workers: a follow up.

    PubMed Central

    Thériault, G; Gingras, S; Provencher, S

    1984-01-01

    A five step investigation was carried out to gain a better understanding of the morbidity that accompanied the development of telangiectasia on aluminium workers and to find its cause. Fifty workers with multiple telangiectasia when matched with normal controls showed the same amount of illness except that evidence of ischaemia on the ECG was found in nine cases and one control. The cases did not show an excess of abnormal biochemical tests. The basic histopathological lesion affected the surrounding tissue rather than the vessels themselves. Working in the current environment and wearing masks seems to protect young workers from developing the lesions. The Soderberg and not the prebake process was associated with the lesions; the causative agent is probably a gas that contains both hydrocarbons and fluoride components emitted from the electrolytic reactors. PMID:6743585

  1. DNA strand patterns on aluminium thin films.

    PubMed

    Khatir, Nadia Mahmoudi; Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Majid, Wan Haliza Abd; Rahman, Saadah Abdul; Shahhosseini, Fatemeh

    2011-01-01

    A new patterning method using Deoxyribose Nucleic Acid (DNA) strands capable of producing nanogaps of less than 100 nm is proposed and investigated in this work. DNA strands from Bosenbergia rotunda were used as the fundamental element in patterning DNA on thin films of aluminium (Al) metal without the need for any lithographic techniques. The DNA strands were applied in buffer solutions onto thin films of Al on silicon (Si) and the chemical interactions between the DNA strands and Al creates nanometer scale arbitrary patterning by direct transfer of the DNA strands onto the substrate. This simple and cost-effective method can be utilized in the fabrication of various components in electronic chips for microelectronics and Nano Electronic Mechanical System (NEMS) applications in general.

  2. Electrochemical Codeposition of Al-Li-Mg Alloys at Solid Aluminum Electrode from LiCl-KCl-MgCl2 Molten Salt System

    NASA Astrophysics Data System (ADS)

    Ye, Ke; Zhang, Mi Lin; Chen, Ye; Han, Wei; de Yan, Yong; Cao, Peng

    2010-06-01

    The electrochemical codeposition of Mg and Li at an aluminium electrode in LiCl-KCl (50:50 wt pct) melts containing different concentrations of MgCl2 at 893 K (620 °C) to form Al-Li-Mg alloys was investigated. Cyclic voltammograms showed that the potential of Li metal deposition at an Al electrode, before the addition of MgCl2, is more positive than that of Li metal deposition at an Mo electrode, which indicated the formation of an Al-Li alloy. The underpotential deposition of magnesium at an aluminium electrode leads to the formation of Al-Mg alloys, and the succeeding underpotential deposition of lithium on predeposited Al-Mg alloys leads to the formation of Al-Li-Mg alloys. Chronopotentiometric measurements indicated that the codeposition of Mg and Li occurs at current densities lower than -0.668 A cm-2 in LiCl-KCl-MgCl2 (8 wt pct) melts at an aluminium electrode. The chronoamperometric studies indicated that the onset potential for the codeposition of Mg and Li is -2.000 V, and the codeposition of Mg and Li at an aluminium electrode is formed into Al-Li-Mg alloys when the applied potentials are more negative than -2.000 V. X-ray diffraction and inductively coupled plasma analysis indicated that Al-Li-Mg alloys with different lithium and magnesium contents were prepared via potentiostatic and galvanostatic electrolysis. The microstructure of typical dual phases of the Al-Li-Mg alloy was characterized by an optical microscope and by scanning electron microscopy. The analysis of energy dispersive spectrometry showed that the elements of Al and Mg distribute homogeneously in the Al-Li-Mg alloy. The lithium and magnesium contents of Al-Li-Mg alloys can be controlled by MgCl2 concentrations and by electrolytic parameters.

  3. Aluminium leaching from red mud by filamentous fungi.

    PubMed

    Urík, Martin; Bujdoš, Marek; Milová-Žiaková, Barbora; Mikušová, Petra; Slovák, Marek; Matúš, Peter

    2015-11-01

    This contribution investigates the efficient and environmentally friendly aluminium leaching from red mud (bauxite residue) by 17 species of filamentous fungi. Bioleaching experiments were examined in batch cultures with the red mud in static, 7-day cultivation. The most efficient fungal strains in aluminium bioleaching were Penicillium crustosum G-140 and Aspergillus niger G-10. The A. niger G-10 strain was capable to extract up to approximately 141 mg·L(-1) of aluminium from 0.2 g dry weight red mud. Chemical leaching with organic acids mixture, prepared according to A. niger G-10 strain's respective fungal excretion during cultivation, proved that organic acids significantly contribute to aluminium solubilization from red mud. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Manufacturing and Machining Challenges of Hybrid Aluminium Metal Matix Composites

    NASA Astrophysics Data System (ADS)

    Baburaja, Kammuluri; Sainadh Teja, S.; Karthik Sri, D.; Kuldeep, J.; Gowtham, V.

    2017-08-01

    Manufacturing which involves material removal processes or material addition processes or material transformation processes. One or all the processes to obtain the final desired properties for a material with desired shape which meets the required precision and accuracy values for the expected service life of a material in working conditions. Researchers found the utility of aluminium to be the second largest after steel. Aluminium and its metal matrix composite possess wide applications in various applications in aerospace industry, automobile industry, Constructions and even in kitchen utensils. Hybrid Al-MMCconsist of two different materials, and one will be from organic origin along with the base material. In this paper an attempt is made to bring out the importance of utilization of aluminium and the challenges concerned in manufacturing and machining of hybrid aluminium MMC.

  5. Aluminium assay and evaluation of the local reaction at several time points after intramuscular administration of aluminium containing vaccines in the Cynomolgus monkey.

    PubMed

    Verdier, François; Burnett, Roger; Michelet-Habchi, Claire; Moretto, Philippe; Fievet-Groyne, Françoise; Sauzeat, Elisabeth

    2005-02-03

    Aluminium hydroxide and aluminium phosphate have been widely used as vaccine adjuvants with a good safety record for several decades. The recent observation in human deltoid muscle of macrophage aggregates containing aluminium hydroxide spicules and termed Macrophagic Myofasciitis (MMF) has encouraged research on aluminium salts. This study was conducted in order to further investigate the clearance of aluminium at the vaccine injection site and the features of induced histopathological lesions. Two groups of 12 monkeys were immunised in the quadriceps muscle with Diphtheria-Tetanus vaccines, which were adjuvanted with either aluminium hydroxide or aluminium phosphate. Three, six or twelve months after vaccination, four monkeys from each group were sacrificed and histopathological examination and aluminium assays were performed on quadriceps muscle sections. Histopathological lesions, similar to the MMF described in humans, were observed and were still present 3 months after aluminium phosphate and 12 months after aluminium hydroxide adjuvanted vaccine administration. An increase in aluminium concentration, more marked in the area of the lesions, was also observed at the 3- and 6-month time points. These findings were localised at the injection site and no similar changes were observed in the distal or proximal muscle fragments. We conclude from this study that aluminium adjuvanted vaccines administered by the intramuscular route trigger histopathological changes restricted to the area around the injection site which persist for several months but are not associated with abnormal clinical signs.

  6. CHIP MORPHOLOGY AND HOLE SURFACE TEXTURE IN THE DRILLING OF CAST ALUMINUM ALLOYS. (R825370C057)

    EPA Science Inventory

    The effects of cutting fluid and other process variables on chip morphology when drilling cast aluminium alloys are investigated. The effects of workpiece material, speed, feed, hole depth, cutting-fluid presence and percentage oil concentration, workpiece temperature, drill t...

  7. CHIP MORPHOLOGY AND HOLE SURFACE TEXTURE IN THE DRILLING OF CAST ALUMINUM ALLOYS. (R825370C057)

    EPA Science Inventory

    The effects of cutting fluid and other process variables on chip morphology when drilling cast aluminium alloys are investigated. The effects of workpiece material, speed, feed, hole depth, cutting-fluid presence and percentage oil concentration, workpiece temperature, drill t...

  8. The binding, transport and fate of aluminium in biological cells.

    PubMed

    Exley, Christopher; Mold, Matthew J

    2015-04-01

    Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion. Copyright © 2014 Elsevier GmbH. All rights reserved.

  9. COS, CS2 and SO 2 in aluminium smelter exhaust : The contribution of aluminium production to the global COS budget.

    PubMed

    Harnisch, J; Borchers, R; Fabian, P

    1995-07-01

    Measurements of carbonyl sulfide (COS) and carbondisulfide (CS2) were carried out on samples drawn from a smoke stack of an aluminium smelter. Volume mixing ratios of 6 ppm COS and 0.1 ppm CS2 were measured for gases from the electrolysis unit that had previously passed an Al2O3 fluid bed reactor and electrostatic precipitators. Specific emissions of 1.6 kg COS and 0.03 kg CS2 per ton of primary aluminium were found. Extrapolating from this particular smelter's conditions to a world mix specific COS emissions of about 4 kg/t(Al) are calculated resulting in emissions of annually 0.08 Tg COS into the atmosphere due to electrolytic aluminium production in 1995. Besides the photochemical conversion of anthropogenic CS2 aluminium production is established to be the second major industrial source of COS probably exceeding automotive tire wear's and coal combustion's contributions.

  10. High-rate aluminium yolk-shell nanoparticle anode for Li-ion battery with long cycle life and ultrahigh capacity

    PubMed Central

    Li, Sa; Niu, Junjie; Zhao, Yu Cheng; So, Kang Pyo; Wang, Chao; Wang, Chang An; Li, Ju

    2015-01-01

    Alloy-type anodes such as silicon and tin are gaining popularity in rechargeable Li-ion batteries, but their rate/cycling capabilities should be improved. Here by making yolk-shell nanocomposite of aluminium core (30 nm in diameter) and TiO2 shell (∼3 nm in thickness), with a tunable interspace, we achieve 10 C charge/discharge rate with reversible capacity exceeding 650 mAh g−1 after 500 cycles, with a 3 mg cm−2 loading. At 1 C, the capacity is approximately 1,200 mAh g−1 after 500 cycles. Our one-pot synthesis route is simple and industrially scalable. This result may reverse the lagging status of aluminium among high-theoretical-capacity anodes. PMID:26243004

  11. High-rate aluminium yolk-shell nanoparticle anode for Li-ion battery with long cycle life and ultrahigh capacity.

    PubMed

    Li, Sa; Niu, Junjie; Zhao, Yu Cheng; So, Kang Pyo; Wang, Chao; Wang, Chang An; Li, Ju

    2015-08-05

    Alloy-type anodes such as silicon and tin are gaining popularity in rechargeable Li-ion batteries, but their rate/cycling capabilities should be improved. Here by making yolk-shell nanocomposite of aluminium core (30 nm in diameter) and TiO2 shell (∼3 nm in thickness), with a tunable interspace, we achieve 10 C charge/discharge rate with reversible capacity exceeding 650 mAh g(-1) after 500 cycles, with a 3 mg cm(-2) loading. At 1 C, the capacity is approximately 1,200 mAh g(-1) after 500 cycles. Our one-pot synthesis route is simple and industrially scalable. This result may reverse the lagging status of aluminium among high-theoretical-capacity anodes.

  12. Aluminium Pneumoconiosis II. Effect on the Rat Lung of Intratracheal Injections of Stamped Aluminium Powders Containing Different Lubricating Agents and of a Granular Aluminium Powder

    PubMed Central

    Corrin, B.

    1963-01-01

    Three stamped aluminium powders were injected into the lungs of rats. One powder contained stearine and another mineral oil, whilst the third had had its lubricant removed. The powders produced a rapid and marked fibrosis of equal severity. It is concluded that aluminium rather than any additive in the powders is the fibrogenic agent. The protective action of stearine demonstrated in vitro was not confirmed in vivo, suggesting that pulmonary fibrosis may also occur in men handling stearine-containing powders. Such a case has recently been reported by McLaughlin et al. (1962), but this is exceptional to the general industrial experience. A granular aluminium powder was also injected into the lungs of rats. In accordance with the results of in vitro experiments, this produced only minimal fibrosis, contrasting strongly with the action of the stamped powders. Images PMID:14072617

  13. Azide SHS of aluminium nitride nanopowder and its application for obtaining Al-Cu-AlN cast nanocomposite

    NASA Astrophysics Data System (ADS)

    Titova, Y. V.; Sholomova, A. V.; Kuzina, A. A.; Maidan, D. A.; Amosov, A. P.

    2016-11-01

    Method of azide self-propagating high-temperature synthesis (SHS-Az), using sodium azide (NaN3) as a nitriding reagent, was used for obtaining the nanopowder of aluminum nitride (AlN) from precursor that was sodium hexafluoroaluminate (Na3AlF6). The product of burning the mixture of Na3AlF6 + 3NaN3 after water rinsing consisted of micro - and nanoparticles of AlN (65%) and the residue of salt Na3AlF6 (35%). This product of SHS-Az was mixed with copper powder and pressed into a briquette of nanopowdery master alloy Cu- 4%(65%AlN+35%Na3AlF6), which was successfully introduced into aluminium melt at a temperature of 850°C. The salt Na3AlF6 in the product of combustion played a role of flux during introducing into the aluminum melt and was not included in the final composition of the composite alloy. The microstructure of the obtained cast composite aluminum alloy with the calculated composition of Al-1.2%Cu-0.035%AlN showed that the reinforcing particles of AlN of different sizes, including nanoparticles, were distributed mainly along the grain boundaries of the aluminum alloy.

  14. Aluminum alloy

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  15. Aluminum alloy

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  16. PLUTONIUM ALLOYS

    DOEpatents

    Chynoweth, W.

    1959-06-16

    The preparation of low-melting-point plutonium alloys is described. In a MgO crucible Pu is placed on top of the lighter alloying metal (Fe, Co, or Ni) and the temperature raised to 1000 or 1200 deg C. Upon cooling, the alloy slug is broke out of the crucible. With 14 at. % Ni the m.p. is 465 deg C; with 9.5 at. % Fe the m.p. is 410 deg C; and with 12.0 at. % Co the m.p. is 405 deg C. (T.R.H.) l6262 l6263 ((((((((Abstract unscannable))))))))

  17. The influence of laser alloying on the structure and mechanical properties of AlMg5Si2Mn surface layers

    NASA Astrophysics Data System (ADS)

    Pakieła, W.; Tański, T.; Brytan, Z.; Labisz, K.

    2016-04-01

    The goal of this paper was focused on investigation of microstructure and properties of surface layer produced during laser surface treatment of aluminium alloy by high-power fibre laser. The performed laser treatment involves remelting and feeding of Inconel 625 powder into the aluminium surface. As a base metal was used aluminium alloy AlMg5Si2Mn. The Inconel powder was injected into the melt pool and delivered by a vacuum feeder at a constant rate of 4.5 g/min. The size of Inconel alloying powder was in the range 60-130 µm. In order to remelt the aluminium alloy surface, the fibre laser of 3 kW laser beam power has been used. The linear laser scan rate of the beam was set 0.5 m/min. Based on performed investigations, it was possible to obtain the layer consisting of heat-affected zone, transition zone and remelted zone, without cracks and defects having much higher hardness value compared to the non-alloyed material.

  18. Dialysis encephalopathy in a non-dialysed uraemic boy treated with aluminium hydroxide orally.

    PubMed

    Nathan, E; Pedersen, S E

    1980-11-01

    Brain aluminium concentration has been found significantly higher in patients dying with dialysis encephalopathy than in uraemic patients without this syndrome, and it has previously been reported only in haemodialysed patients. We report a case of high brain aluminium concentration in a uraemic boy showing symptoms of severe encephalopathy. He was never dialysed but only treated with aluminium hydroxide orally. Baluarte reported corresponding symptoms in nondialysed uraemic children, but brain aluminium concentrations were not reported. His patients as well as our had very high levels of parathormone which may play a role in the resorption and distribution of aluminium. Aluminium preparations should be avoided in children with renal failure.

  19. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  20. BRAZING ALLOYS

    DOEpatents

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.

    1962-02-20

    A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)

  1. Accumulation and toxicity of aluminium-contaminated food in the freshwater crayfish, Pacifastacus leniusculus.

    PubMed

    Woodburn, Katie; Walton, Rachel; McCrohan, Catherine; White, Keith

    2011-10-01

    The accumulation and toxicity of aluminium in freshwater organisms have primarily been examined following aqueous exposure. This study investigated the uptake, excretion and toxicity of aluminium when presented as aluminium-contaminated food. Adult Pacifastacus leniusculus were fed control (3 μg aluminium/g) or aluminium-spiked pellets (420 μg aluminium/g) over 28 days. Half the crayfish in each group were then killed and the remainder fed control pellets for a further 10 days (clearance period). Concentrations of aluminium plus the essential metals calcium, copper, potassium and sodium were measured in the gill, hepatopancreas, flexor muscle, antennal gland (kidney) and haemolymph. Histopathological analysis of tissue damage and sub-cellular distribution of aluminium were examined in the hepatopancreas. Haemocyte number and protein concentration in the haemolymph were analysed as indicators of toxicity. The hepatopancreas of aluminium-fed crayfish contained significantly more aluminium than controls on days 28 and 38, and this amount was positively correlated with the amount ingested. More than 50% of the aluminium in the hepatopancreas of aluminium-fed crayfish was located in sub-cellular fractions thought to be involved in metal detoxification. Aluminium concentrations were also high in the antennal glands of aluminium-fed crayfish suggesting that some of the aluminium lost from the hepatopancreas is excreted. Aluminium exposure via contaminated food caused inflammation in the hepatopancreas but did not affect the number of circulating haemocytes, haemolymph ion concentrations or protein levels. In conclusion, crayfish accumulate, store and excrete aluminium from contaminated food with only localised toxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Segregation phenomena at growing alumina/alloy interfaces

    SciTech Connect

    Hou, Peggy Y.

    2005-03-30

    The chemistry and structure at the scale/alloy interface are important factors governing scale adhesion. The chemical changes can occur from segregation of impurities in the alloy, such as sulphur and carbon, or alloying elements such as chromium, aluminium and reactive elements. This paper reviews studies of the changes of interfacial composition with oxidation time for Al{sub 2}O{sub 3} formed on several model alumina-forming alloys, and tries to relate that to the interfacial strength. Results show that sulphur segregation to oxide/metal interfaces can indeed occur, but the type and amount of segregants at the interface depend on the alloy composition and the interface structure. Co-segregation of impurities with alloying elements can also occur, resulting in multi-layer segregants at the interface. Sulphur-containing interfaces are indeed weaker, but the major role of sulphur is to enhance interfacial void formation. Reactive elements in the alloy not only gather sulfur but also exert an additional positive effect on scale adhesion.

  3. Formability Analysis of Magnesium Alloy Sheet Bulging Using FE Simulation

    SciTech Connect

    Mac Donald, B. J.; Hunt, D.; Yoshihara, S.; Manabe, K.

    2007-05-17

    There is currently much focus on the application of magnesium alloys to automotive structural components. This has arisen due to the positive environmental aspects associated with use of magnesium alloys such as weight reduction and recycling potential. In recent years many researchers have focused on the application of various forming processes to magnesium alloys. Magnesium alloys would seem highly suitable for sheet forming due to high N and r values, however, in application their formability has been inferior to, for example, aluminium alloys. It has thus been concluded that, when dealing with magnesium alloys, it is difficult to predict formability based on material properties. In order to improve formability and forming accuracy when using Mg alloys it is necessary to build a database and inference system which could decide the optimal forming parameters for complex automotive components. Currently not enough data is available to build such a database due to the limited number of studies available in literature. In this study an experimental analysis of hemispherical bulge forming at elevated temperature was undertaken in order to evaluate formability and hence build a database for forming process design. A finite element model based on the experiment has been built and validated against the experimental results. A ductile failure criterion has been integrated with the FE model and is used to predict the onset of failure. This paper discusses the development and validation of the finite element model with the ductile failure criterion and presents results from the experimental tests and FE simulations.

  4. Investigation of electrorefining of metallic alloy fuel onto solid Al cathodes

    NASA Astrophysics Data System (ADS)

    Cassayre, L.; Malmbeck, R.; Masset, P.; Rebizant, J.; Serp, J.; Soucek, P.; Glatz, J.-P.

    2007-01-01

    This work concerned the electrorefining of UZr and UPuZr alloys on a solid aluminium cathode, in the LiCl-KCl eutectic melt containing U 3+, Pu 3+, Np 3+, Zr 2+ or Zr 4+, Am 3+, Nd 3+, Y 3+, Ce 3+ and Gd 3+ chlorides. During constant current electrolyses, the use of a cathodic cut-off potential (-1.25 V versus Ag/AgCl) allowed to selectively deposit actinides (mainly U), while lanthanides remained in the salt. The aim was to determine the maximal load achievable on a single aluminium electrode. The total exchange charge was 4300 C, which represents the deposition of 3.72 g of actinides in 4.17 g Al, yielding a composition of 44.6 wt% An in Al. It was shown that the melting of the cathode contributed to increase the total amount of actinides deposited on the aluminium.

  5. [Association between serum aluminium level and methylation of amyloid precursor protein gene in workers engaged in aluminium electrolysis].

    PubMed

    Yang, X J; Yuan, Y Z; Niu, Q

    2016-04-20

    To investigate the association between serum aluminium level and methylation of the promoter region of amyloid precursor protein (APP)gene in workers engaged in aluminium electrolysis. In 2012, 366 electrolysis workers in an aluminium factory were enrolled as exposure group (working years >10 and age >40 years)and divided into low-exposure group and high-exposure group based on the median serum aluminium level. Meanwhile, 102 workers in a cement plant not exposed to aluminium were enrolled as control group. Graphite furnace atomic absorption spectrometry was used to measure serum aluminium level, methylation specific PCR was used to measure the methylation rate of the promoter region of APP gene, and ELI-SA was used to measure the protein expression of APP in lymphocytes in peripheral blood. The exposure group had a significantly higher serum aluminium level than the control group (45.07 μg/L vs 30.51 μg/L, P< 0.01). The exposure group had a significantly lower methylation rate of the promoter region of APP gene than the control group (18.85% vs 25.49%, P=0.025), and the high-exposure group had a significantly lower methylation rate of the promoter region of APP gene than the low-exposure group (15.84% vs 21.85%, P<0.05). The exposure group had a significantly higher protein expression of APP in lymphocytes in peripheral blood than the control group (66.73 ng/ml vs 54.17 ng/ml, P<0.05); compared with the low-exposure group (65.39 ng/ml), the high-exposure group showed an increase in the protein expression of APP in lymphocytes in peripheral blood (67.22 ng/ml), but there was no significant difference between these two groups (P>0.05). The multivariate logistic regression analysis showed that with reference to the control group, low aluminium exposure (OR=1.86, 95% CI 1.67~3.52)and high aluminium exposure (OR=2.98, 95% CI 1.97~4.15)were risk factors for a reduced methylation rate of the promoter region of APP gene. Reduced methylation of the promoter region of APP

  6. Computer Modelling of Age Hardening for Isothermally Aged Al-Mg-Si Alloys

    NASA Astrophysics Data System (ADS)

    Wu, Linda; Ferguson, W. George

    Computer modelling, due to it saving time and money, has been widely used in industrial simulation. The present model, which is based on the Shercliff-Ashby methodology for the ageing of aluminum alloys, can be used to predict the yield strength (or hardness) of Al-Mg-Si alloys for the artificial ageing temperature below the solvus temperature as a function of time. With suitable input data, this model can be applied to most Al-Mg-Si alloys, wrought or cast. In the present model, input data for aluminium alloys of A356, A357 and 6061 is taken from the open literature, and then the unknown constants are calibrated from these data. After calibration, the ageing curves are constructed for different isothermal ageing temperatures. Finally, experimentally ageing heat treatments at different temperatures for casting alloys of A356 were done to validate the model.

  7. Fuzzy Multicriteria Ranking of Aluminium Coating Methods

    NASA Astrophysics Data System (ADS)

    Batzias, A. F.

    2007-12-01

    This work deals with multicriteria ranking of aluminium coating methods. The alternatives used are: sulfuric acid anodization, A1; oxalic acid anodization, A2; chromic acid anodization, A3; phosphoric acid anodization, A4; integral color anodizing, A5; chemical conversion coating, A6; electrostatic powder deposition, A7. The criteria used are: cost of production, f1; environmental friendliness of production process, f2; appearance (texture), f3; reflectivity, f4; response to coloring, f5; corrosion resistance, f6; abrasion resistance, f7; fatigue resistance, f8. Five experts coming from relevant industrial units set grades to the criteria vector and the preference matrix according to a properly modified Delphi method. Sensitivity analysis of the ranked first alternative A1 against the `second best', which was A3 at low and A7 at high resolution levels proved that the solution is robust. The dependence of anodized products quality on upstream processes is presented and the impact of energy price increase on industrial cost is discussed.

  8. Neurocognitive effects in welders exposed to aluminium.

    PubMed

    Giorgianni, Concetto Mario; D'Arrigo, Graziella; Brecciaroli, Renato; Abbate, Adriana; Spatari, Giovanna; Tringali, Maria Antonietta; Gangemi, Silvia; De Luca, Annamaria

    2014-05-01

    Various authors who studied the effects of aluminium (Al) exposure on the neurocognitive system in the last 30 years have reached different and often contradictory conclusions. The aim of this study is to help clarify the effects that the metal causes on cognitive ability in a group of naval welders exposed to Al. The study was performed on a sample of 86 male Al welders in a shipyard in Messina. The average value of environmental Al, recorded in the workplace, was 19.5 mg/m(3). The blood levels of Al, zinc, manganese, lead and chromium were monitored in all the subjects. The reagents used for the neuropsychic study were the Wechsler Memory Scale (WMS), the Colour Word Test or Stroop Test and the Test of Attention Matrixes. The results were compared with those obtained in a similar control group not exposed to Al and with an Al-b value of 6.93 g/l. For all the mental reagents used, the reply is obtained in the sample of exposed subjects showed decreased cognitive response with regard to attention and memory performance. The comparison between the individual tests showed greater sensitivity of performance studied using the WMS and the Stroop Test compared with the Test of Attention Matrixes. The alterations encountered in the cognitive functions studied increased proportionally to time of exposure and quantity of metal absorbed. The study confirmed that occupational exposure to Al causes alteration in cognitive responses that are more evident in complex functions.

  9. Biological monitoring of welders exposed to aluminium.

    PubMed

    Rossbach, Bernd; Buchta, Mark; Csanády, György A; Filser, Johannes G; Hilla, Wolfgang; Windorfer, Klaus; Stork, Joachim; Zschiesche, Wolfgang; Gefeller, Olaf; Pfahlberg, Annette; Schaller, Karl-Heinz; Egerer, Ellen; Escobar Pinzón, Luis Carlos; Letzel, Stephan

    2006-04-10

    To evaluate an adequate strategy for biological monitoring of aluminium (Al), a group of 62 Al welders (age in 1999: 23-51 years, median 35 years) was surveyed annually from 1999 to 2003 by determination of pre- and post-shift Al in urine and plasma. Biomonitoring was supplemented by personal air measurements of the total dust concentration. The welders' internal exposure was compared to the exposure of 60 non-exposed assembly workers (age in 1999: 21-51 years, median: 36 years) who were surveyed in 1999, 2001 and 2003. Having a nearly constant dust exposure, median concentrations of Al in urine (Al in plasma) of the welders decreased from 40.1 microg/g to 19.8 microg/g creatinine (8.7 to 4.6 microg/l). For the control group the median levels of Al in urine (plasma) ranged from 4.8 microg/g to 5.2 microg/g creatinine (2.4-4.3 microg/l) indicating a higher sensitivity for the marker Al in urine. No systematic differences have been found between pre- and post-shift internal exposure. This might be caused by the slow elimination kinetics and low systemic bioavailability of Al. A correlation analysis did not yield close relationships between dust exposure, Al in plasma and Al in urine underlining the importance of biomonitoring for assessment of Al exposure.

  10. Corrosion of aluminium in soft drinks.

    PubMed

    Seruga, M; Hasenay, D

    1996-04-01

    The corrosion of aluminium (Al) in several brands of soft drinks (cola- and citrate-based drinks) has been studied, using an electrochemical method, namely potentiodynamic polarization. The results show that the corrosion of Al in soft drinks is a very slow, time-dependent and complex process, strongly influenced by the passivation, complexation and adsorption processes. The corrosion of Al in these drinks occurs principally due to the presence of acids: citric acid in citrate-based drinks and orthophosphoric acid in cola-based drinks. The corrosion rate of Al rose with an increase in the acidity of soft drinks, i.e. with increase of the content of total acids. The corrosion rates are much higher in the cola-based drinks than those in citrate-based drinks, due to the facts that: (1) orthophosphoric acid is more corrosive to Al than is citric acid, (2) a quite different passive oxide layer (with different properties) is formed on Al, depending on whether the drink is cola or citrate based. The method of potentiodynamic polarization was shown as being very suitable for the study of corrosion of Al in soft drinks, especially if it is combined with some non-electrochemical method, e.g. graphite furnace atomic absorption spectrometry (GFAAS).

  11. On the shock response of the magnesium alloy Elektron 675

    NASA Astrophysics Data System (ADS)

    Hazell, Paul; Appleby-Thomas, Gareth; Siviour, Clive; Wielewski, Euan

    2011-06-01

    Alloying elements such as aluminium, zinc or rare-earths allow precipitation hardening of magnesium (Mg). The low densities of such strengthened Mg alloys have led to their adoption as aerospace materials and (more recently) they are being considered as armour materials. Consequently, understanding their response to high-strain rate loading is becoming increasingly important. Here, the plate-impact technique was employed to measure longitudinal stress evolution in armour-grade wrought Mg-alloy Elektron 675 under 1D shock loading. The strength and spall behaviour was interrogated, with an estimate made of the material's Hugoniot elastic limit. Finally, electron backscatter diffraction (EBSD) techniques were employed to investigate post-shock microstructural changes.

  12. Corrosion of aluminium metal in OPC- and CAC-based cement matrices

    SciTech Connect

    Kinoshita, Hajime; Swift, Paul; Utton, Claire; Carro-Mateo, Beatriz; Collier, Nick; Milestone, Neil

    2013-08-15

    Corrosion of aluminium metal in ordinary Portland cement (OPC) based pastes produces hydrogen gas and expansive reaction products causing problems for the encapsulation of aluminium containing nuclear wastes. Although corrosion of aluminium in cements has been long known, the extent of aluminium corrosion in the cement matrices and effects of such reaction on the cement phases are not well established. The present study investigates the corrosion reaction of aluminium in OPC, OPC-blast furnace slag (BFS) and calcium aluminate cement (CAC) based systems. The total amount of aluminium able to corrode in an OPC and 4:1 BFS:OPC system was determined, and the correlation between the amount of calcium hydroxide in the system and the reaction of aluminium obtained. It was also shown that a CAC-based system could offer a potential matrix to incorporate aluminium metal with a further reduction of pH by introduction of phosphate, producing a calcium phosphate cement.

  13. MOCVD of aluminium oxide films using aluminium β-diketonates as precursors

    NASA Astrophysics Data System (ADS)

    Devi, A.; Shivashankar, S. A.; Samuelson, A. G.

    2002-06-01

    Deposition of Al203 coatings by CVD is of importance because they are often used as abrading material in cemented carbide cutting tools. The conventionally used CVD process for Al203 involves the corrosive reactant AICl3. In this paper, we report on the thermal characterisation of the metalorganic precursors namely aluminium tris-tetramethyl-heptanedionate [ Al(thd)3] and aluminium tris-acetylacetonate [ Al(acac)3] and their application to the CVD of Al203 films. Crystalline A1203 films were deposited by MOCVD at low temperatures by the pyrolysis of Al(thd)3 and AI(acac)3. The films were deposited on a TiN-coated tungsten carbide (TiN/WC) and Si(100) substrates in the temperature range 500-1100 °C. The as-deposited films were characterised by x-ray diffraction, optical microscopy, scanning and transmission electron microscopy, Auger electron spectroscopy. The observed crystallinity of films grown at low temperatures, their microstructure, and composition may be interpreted in terms of a growth process that involves the melting of the metalorganic precursor on the hot growth surface.

  14. Improving Efficiency of Aluminium Sacrificial Anode Using Cold Work Process

    NASA Astrophysics Data System (ADS)

    Asmara, Y. P.; Siregar, J. P.; Tezara, C.; Ann, Chang Tai

    2016-02-01

    Aluminium is one of the preferred materials to be used as sacrificial anode for carbon steel protection. The efficiency of these can be low due to the formation of oxide layer which passivate the anodes. Currently, to improve its efficiency, there are efforts using a new technique called surface modifications. The objective of this research is to study corrosion mechanism of aluminium sacrificial anode which has been processed by cold work. The cold works are applied by reducing the thickness of aluminium sacrificial anodes at 20% and 40% of thickness reduction. The cathodic protection experiments were performed by immersion of aluminium connected to carbon steel cylinder in 3% NaCl solutions. Visual inspections using SEM had been conducted during the experiments and corrosion rate data were taken in every week for 8 weeks of immersion time. Corrosion rate data were measured using weight loss and linear polarization technique (LPR). From the results, it is observed that cold worked aluminium sacrificial anode have a better corrosion performance. It shows higher corrosion rate and lower corrosion potential. The anodes also provided a long functional for sacrificial anode before it stop working. From SEM investigation, it is shown that cold works have changed the microstructure of anodes which is suspected in increasing corrosion rate and cause de-passivate of the surface anodes.

  15. Cancer risk among workers of a secondary aluminium smelter.

    PubMed

    Maltseva, A; Serra, C; Kogevinas, M

    2016-07-01

    Cancer risk in secondary aluminium production is not well described. Workers in this industry are exposed to potentially carcinogenic agents from secondary smelters that reprocess aluminium scrap. To evaluate cancer risk in workers in a secondary aluminium plant in Spain. Retrospective cohort study of male workers employed at an aluminium secondary smelter (1960-92). Exposure histories and vital status through 2011 were obtained through personal interviews and hospital records, respectively. Standardized mortality (SMRs) and incidence ratios (SIRs) were calculated. The study group consisted of 98 workers. We found increased incidence and mortality from bladder cancer [SIR = 2.85, 95% confidence interval (CI) 1.23-5.62; SMR = 5.90, 95% CI 1.58-15.11]. Increased incidence was also observed for prostate cancer and all other cancers but neither were statistically significant. No increased risk was observed for lung cancer. Results of this study suggest that work at secondary aluminium smelters is associated with bladder cancer risk. Identification of occupational carcinogens in this industry is needed. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Aluminium recycling and environmental issues of salt slag treatment.

    PubMed

    Xiao, Yanping; Reuter, Markus A; Boin, Udo

    2005-01-01

    Environmental friendly recycling is the trend toward total recycling of aluminium metal. In the secondary aluminium industry, due to the complexity of compositions and contaminants in the various types of aluminium scraps, an understanding of the behavior of different scraps during melting is crucial in the recycling process. Salt slags are the byproducts of the secondary aluminium industry, which should be recycled and processed in a proper way by taking the environmental impact into consideration. This article provides qualitative assessment on 10 different commercial aluminium scraps for their relative recyclability via well-designed and controlled laboratory experiments. It confirms that more nonmetallic contaminants, smaller size, and higher ratio of surface area to body volume generally lead to a lower metal recovery. Recycling the scraps with lower recyclability normally generates more salt slags. High slag viscosity leads to more fine aluminum metal entrapped in the salt slag and thus increases the load of salt slag recycling. It was found that viscosity of the salt flux is increased with the amount of entrapped nonmetallic components, which affect the settling of heavier materials. In addition, the slag samples from the melting tests were leached and analyzed to evaluate the behavior of carbon containing scrap. The elevated carbon content in the scrap resulted in more carbide formation in salt slags and thus more methane generation in salt slag recycling with a higher environmental impact.

  17. Online monitoring of aluminium in drinking water with fluorimetric detection.

    PubMed

    Alonso-Mateos, A; Almendral-Parra, M J; Curto-Serrano, Y; Rodríguez-Martín, F J

    2008-01-01

    We report a procedure for the online monitoring of aluminium in drinking water by flow injection analysis. The reaction used is the formation of a complex with morin. Under the working conditions, this can be accomplished in an ethanol-rich hydroalcoholic medium, which modifies the fluorescent characteristics of the complex, allowing the determination of aluminium concentrations higher than 3.1 microgl(-1), with a linear application range between 2 and 250 microgl(-1), an R.S.D. of 2.3% (n=10, 120 microgl(-1)) and a sampling frequency of 90 h(-1). The method can thus be considered one of the most sensitive and fastest for the continuous determination of aluminium. In the presence of anionic surfactants, the sensitivity of the determination is increased. In this form, aluminium is detected at concentrations higher than 2.8 microgl(-1), with a linear application range of 2-50 microgl(-1). The procedure was applied to the analysis of aluminium in drinking, river, and underground water. Under the proposed working conditions, only Fe(III), fluoride and phosphates interfere. The interference of Fe(III) can be avoided with hydroxylamine and that of phosphates and polyphosphates by acid digestion of the samples.

  18. Effects of aqueous aluminium on four fish ectoparasites.

    PubMed

    Pettersen, Ruben A; Vøllestad, L Asbjørn; Flodmark, Lars E W; Poléo, Antonio B S

    2006-10-01

    Effects of aqueous aluminium on four species of fish ectoparasites were studied. Fish infected by Gyrodactylus derjavini, G. macronychus and Anodonta anatina glochidia, and free living Argulus foliaceus were exposed to acidic Al-rich water (pH 5.8), acidic Al-poor water (pH 5.8) and control water (pH 6.3). The results showed that aqueous aluminium had a negative effect on the ectoparasites tested, without any apparent negative effect on the fish hosts. The effect of aluminium was dependent on the kind of organism tested. The gyrodactylids were eliminated, while the duck mussel glochidia showed a decrease in abundance when exposed to 200-260 mug Al/l at pH 5.8. The little fish louse showed increased mortality rate when exposed to aluminium. The effects of aluminium on the parasites in the present study confirm the importance of water quality in general, and acidification in particular, for the distribution and population dynamics of ectoparasites in freshwater environments.

  19. In situ observation and analysis of ultrasonic capillary effect in molten aluminium.

    PubMed

    Tzanakis, I; Xu, W W; Eskin, D G; Lee, P D; Kotsovinos, N

    2015-11-01

    An in situ synchrotron radiographic study of a molten Al-10 wt% Cu alloy under the influence of an external ultrasonic field was carried out using the Diamond-Manchester Branchline pink X-ray imaging at the Diamond Light Source in UK. A bespoke test rig was used, consisting of an acoustic transducer with a titanium sonotrode coupled with a PID-controlled resistance furnace. An ultrasonic frequency of 30 kHz, with a peak to peak amplitude at 140 microns, was used, producing a pressure output of 16.9 MPa at the radiation surface of the 1-mm diameter sonotrode. This allowed quantification of not only the cavitation bubble formation and collapse, but there was also evidence of the previously hypothesised ultrasonic capillary effect (UCE), providing the first direct observations of this phenomenon in a molten metallic alloy. This was achieved by quantifying the re-filling of a pre-existing groove in the shape of a tube (which acted as a micro-capillary channel) formed by the oxide envelope of the liquid sample. Analytical solutions of the flow suggest that the filling process, which took place in very small timescales, was related to micro-jetting from the collapsing cavitation bubbles. In addition, a secondary mechanism of liquid penetration through the groove, which is related with the density distribution of the oxides inside the groove, and practically to the filtration of aluminium melt from oxides, was revealed. The observation of the almost instantaneous re-filling of a micro-capillary channel with the metallic melt supports the hypothesised sono-capillary effect in technologically important liquids other than water, like metallic alloys with substantially higher surface tension and density.

  20. The chemical phenol extraction of intermetallic particles from casting AlSi5Cu1Mg alloy.

    PubMed

    Mrówka-Nowotnik, G; Sieniawski, J; Nowotnik, A

    2010-03-01

    This paper presents a chemical extraction technique for determination of intermetallic phases formed in the casting AlSi5Cu1Mg aluminium alloy. Commercial aluminium alloys contain a wide range of intermetallic particles that are formed during casting, homogenization and thermomechanical processing. During solidification, particles of intermetallics are dispersed in interdendritic spaces as fine primary phases. Coarse intermetallic compounds that are formed in this aluminium alloy are characterized by unique atomic arrangement (crystallographic structure), morphology, stability, physical and mechanical properties. The volume fraction, chemistry and morphology of the intermetallics significantly affect properties and material behaviour during thermomechanical processing. Therefore, accurate determination of intermetallics is essential to understand and control microstructural evolution in Al alloys. Thus, in this paper it is shown that chemical phenol extraction method can be applied for precise qualitative evaluation. The results of optical light microscopy LOM, scanning electron microscopy SEM and X-ray diffraction XRD analysis reveal that as-cast AlSi5Cu1Mg alloy contains a wide range of intermetallic phases such as Al(4)Fe, gamma- Al(3)FeSi, alpha-Al(8)Fe(2)Si, beta-Al(5)FeSi, Al(12)FeMnSi.