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Sample records for aa5052 aluminium alloy

  1. Microstructural evaluation of friction stir weld of dissimilar aluminium alloys AA 5052 and AA 6061

    International Nuclear Information System (INIS)

    Friction stir welding (FSW), a solid state joining technique is being extensively used in the similar as well as dissimilar joining of Al, Mg, Cu, Ti and their alloys. In this process, the plates to be welded are abutted and a non-consumable tool rotating at higher speeds is plunged through the thickness at the joint. It is then moved along the joint line, frictionally heating the material which leads to material softening, which then easily moves behind the tool and forms a solid state weld as the stirred material is consolidated. With this process a wide range of combination of dissimilar materials (which previously were considered incompatible for welding) is possible today. Friction stir welding trials of 5 mm thick plates of two aluminium alloys - AA 6061 and AA 5052 were carried out at tool rotation speeds of 1120 and 1400 rpm and tool traverse speeds of 60, 80 and 100 mm/min. The transverse cross section of the weld was used for optical as well as electron microscopy observations. A microhardness profile was obtained in the mid- thickness region across the weld structure using a load of 50 g and a 10 s dwell time. For analytical microscopy, a Cameca SX100 electron probe microanalyzer (EPMA) equipped with three wavelength dispersive spectrometers was used. Standard tensile specimen having gauge length of 25 mm and gauge width of 5 mm were cut using electro discharge machine (EDM) from the welded plates by keeping the tensile axis perpendicular to the welding dirsile axis perpendicular to the welding direction and were tested using screw driven Instron machine at a strain rate of 10-4 sec-1. The fractured surfaces were further examined using secondary electron microscopy (SEM). In this study, a brief description of FSW of dissimilar aluminium alloys is enumerated

  2. The growing rate and the type of corrosion products of aluminium alloy AA 5052 in deionized water at temperature up to 3000C

    International Nuclear Information System (INIS)

    The process of corrosion concerning the aluminum alloy AA5052 in deionized water at temperatures of 400C, 800C, 900C, 1400C, 2000C and 2800C is studied. The following methods are used: periodic weighting of the test samples; analysis by neutronic activation of the corrosion products dissolved in water; thermogravimetric and thermodiferential analysis; analysis through X-ray diffraction and from metalografic observations of the crystals produced in the corrosion process; an optical microscope using polarized and normal light and a scanning electronic microscope. The activation energies are calculated for the corrosion film formation, and for the dissolution of the corrosion products in the deionized water. (ARHC)

  3. [Comparison of texture distribution of cold rolled DC and CC AA 5052 aluminum alloy at different positions through thickness direction by XRD].

    Science.gov (United States)

    Chen, Ming-biao; Ma, Min; Yang, Qing-xiang; Wang, Shan; Liu, Wen-chang; Zhao, Ying-mei

    2013-09-01

    To provide gist of DC AA 5052 and CC AA 5052 aluminum alloy to industry production and application, the texture variation of cold rolled sheets through thickness direction was studied by X-ray diffraction method, and the difference in texture at surface, quarter and center layer was analyzed. The hot plates of direct chill cast (DC) AA 5052 and continuous cast (CC) AA 5052 aluminum alloy were annealed at 454 degrees C for 4 hours and then cold rolled to different reductions. The strength and volume fraction of the fiber in CC AA 5052 aluminum alloy is larger than in DC AA 5052 aluminum alloy after same rolling reduction The volume fraction of the recrystallization texture cube in the CC AA 5052 aluminum alloy is less than in the DC AA 5052 aluminum alloy, which result in that CC AA 5052 aluminum alloy needs less cold rolling reduction than DC AA 5052 aluminum alloy for generating the texture with same intensity and volume fraction at surface layer, quarter layer and center layer. The manufacturability and performance of CC AA 5052 aluminum alloy is superior to DC AA 5052 aluminum alloy for use in stamping. PMID:24369675

  4. Through-thickness texture gradient in continuous cast AA 5052 aluminum alloy sheet

    International Nuclear Information System (INIS)

    The development of through-thickness texture gradient during continuous cast (CC) processing of AA 5052 aluminum alloy was investigated by X-ray diffraction. The CC slab and the hot bands after each of three rolling passes were obtained from an industrial CC processing operation. The results show that a through-thickness texture gradient exists near the surface after the first pass. The subsurface layer exhibits a very weak texture, while the center layer shows the ? fiber rolling texture. After the third pass, a strong ? fiber rolling texture is obtained at different through-thickness layers. The roll-gap geometry does not produce any shear deformation at the intermediate layer. After recrystallization annealing, the through-thickness texture gradient still exists in the AA 5052 aluminum alloy sheets. As the measured position moves towards the center from the surface, the cube recrystallization texture strengthens

  5. Effect of hot and cold deformation on the ? fiber rolling texture in continuous cast AA 5052 aluminum alloy

    International Nuclear Information System (INIS)

    The texture evolution of continuous cast AA 5052 aluminum alloy during hot rolling was investigated by X-ray diffraction. The ? fiber rolling texture formed under various hot and cold deformation conditions was compared. The results show that deformation at elevated temperatures results in a stronger ? fiber rolling texture than that at room temperature

  6. Effect of hot and cold deformation on the recrystallization texture of continuous cast AA 5052 aluminum alloy

    International Nuclear Information System (INIS)

    The effect of different relative amounts of hot and cold deformation on the recrystallization texture of a continuous cast AA 5052 aluminum alloy was investigated by X-ray diffraction. The results show that hot deformation promotes the cube and Goss components at the expense of the r-cube and remainder components. The formation of the R component does not appear to be affected by hot and cold deformation

  7. Effect of temperature on the anodizing process of aluminum alloy AA 5052

    Science.gov (United States)

    Theohari, S.; Kontogeorgou, Ch.

    2013-11-01

    The effect of temperature (10-40 °C) during the anodizing process of AA 5052 for 40 min in 175 g/L sulfuric acid solution at constant voltage (15 V) was studied in comparison with pure aluminum. The incorporated magnesium species in the barrier layer result in the further increase of the minimum current density passed during anodizing, as the temperature increases, by about 42% up to 30 °C and then by 12% up to 40 °C. Then during the anodizing process for 40 min a blocking effect on oxide film growth was gradually observed as the temperature increased until 30 °C. The results of EDAX analysis on thick films reveal that the mean amount of the magnesium species inside the film is about 50-70% less than that in the bulk alloy, while it is higher at certain locations adjacent to the film surface at 30 °C. The increase of anodizing temperature does not influence the porosity of thin films (formed for short times) on pure aluminum, while it reduces it on the alloy. At 40 °C the above mentioned blocking effects disappear. It means that the presence of magnesium species causes an impediment to the effect of temperature on iss, on the film thickness and on the porosity of thin films, only under conditions where film growth takes place without significant loss of the anodizing charge to side reactions.

  8. Recrystallization microstructures and textures in AA 5052 continuous cast and direct chill cast aluminum alloy

    International Nuclear Information System (INIS)

    Commercially produced hot bands of AA 5052 continuous cast (CC) and direct chill (DC) cast aluminum alloys were cold rolled to (thickness) reductions of 70%, 80%, and 90% followed by annealing at different conditions. The recrystallization kinetics are found equivalent for both the CC and DC materials. Recrystallization microstructures are different between the CC and DC materials. Evolution of recrystallization texture in the CC and DC materials were investigated by using three-dimensional orientation distribution functions (ODFs) that were determined by X-ray diffraction. The recrystallization texture was correlated with cold rolling reduction (prior to annealing), annealing temperature, and annealing time. Results showed that the R {124} and cube {001} are dominant recrystallization texture components in both CC and DC materials. During annealing, the intensity and volume fraction of the cube component strongly depend on the prior cold rolling history. In contrast, the intensity and volume fraction of the R component remains almost constant regardless of the different cold rolling reductions prior to annealing. After complete recrystallization, the intensity and volume fraction of both R and cube components appear to be independent of the annealing temperature and annealing time

  9. Fatigue life estimation of different welding zones of oxy acetylene welded aluminum alloy (AA 5052-H32)

    International Nuclear Information System (INIS)

    Fatigue life of aluminum alloys are reviewed mainly on the basis of experimental results. Fatigue strength and failure history of the representative AA5052- H32 are summarized with respect to surface temperature effects during the welding process. In oxy acetylene welding three different zones named as welded zone (WZ), heat affected zone (HAZ) and base metal (BM) are formed having totally varying properties depending on their specific grain structure. Fatigue life and hardness of these different zones are determined in three successive phases of experiments. It is viewed that the grains are shifted from large rough round to elongated oval shaped from WZ to HAZ and relatively small and fine in BM respectively. Depending on grain configuration the fatigue strength increases from WZ to BM due to concentration of grain boundaries, a hindrance in fatigue crack propagation. (author)

  10. Avaliação da geometria de ferramenta e parâmetros do processo FSW na soldagem da liga de alumínio AA 5052 / Process parameters and tool geometry evaluation in the FSW of AA 5052 aluminum alloy

    Scientific Electronic Library Online (English)

    Tiago Valdameri, Capelari; José Antônio Esmerio, Mazzaferro.

    2009-09-01

    Full Text Available A soldagem de ligas de alumínio sem degradação excessiva das propriedades originais do metal base apresenta-se como um obstáculo a ser superado pelas indústrias em seus processos de fabricação, uma vez que o alumínio tem sido usado cada vez de forma mais intensiva. Neste sentido, o processo de solda [...] gem denominado Friction Stir Welding (FSW) tem recebido atenção por suas potencialidades onde o aporte de calor deve ser minimizado ou quando metais dissimilares devem ser soldados. Neste processo, uma ferramenta de alta resistência mecânica e com um perfil especial é utilizada para, por meio de atrito com as peças a serem soldadas, gerar calor e misturar mecanicamente o material da junta, consolidando a solda. Este trabalho visa implementar o processo FSW utilizando uma fresadora universal de elevada rigidez na soldagem de chapas de alumínio AA 5052-H34 com 6,35mm de espessura. Para tanto, três geometrias de ferramentas de soldagem foram projetadas, fabricadas e testadas, de forma a definir-se parâmetros de soldagem compatíveis com as condições fornecidas pela máquina fresadora, por meio de testes preliminares. Definidos estes parâmetros, juntas foram obtidas com as três geometrias de ferramenta disponíveis e seus desempenhos foram comparados. Ensaios mecânicos de dobramento e tração, medição do perfil de microdurezas e análise macrográfica da seção transversal das soldas foram os métodos empregados na caracterização das propriedades resultantes. Em adição, soldas pelo processo MIG também foram obtidas e sujeitas às mesmas avaliações. considerando-se a tensão de escoamento como parâmetro de comparação, as três geometrias testadas apresentaram desempenho similar (em torno de 80% da tensão de escoamento do metal base). Porém, se comparadas com respeito aos valores de ductilidade ou aos testes de dobramento transversal, observou-se que uma das geometrias testadas tem desempenho inferior às demais devido a presença de uma descontinuidade longitudinal no cordão de solda. O perfil de microdureza das amostras soldadas pelo processo FSW demonstrou homogeneidade entre as diferentes zonas microestruturais existentes ao longo da seção transversal, ao passo que as amostras soldadas através do processo MIG apresentaram variação característica dos processos ao arco elétrico. Abstract in english Welding of aluminum alloys with no considerable degradation of the properties of the base metal is a problem to be overcomed by industry manufacturing processes. In the aeronautical industry, no-melt joining processes such as adhesive bonding or riveting are often considered when designing aluminum [...] connections. Alternatively, a welding process named Friction Stir Welding (FSW) is receiving crescent attention for its potential applications where heat input shall be minimized or when dissimilar metals must be joined. In this process a high strength rotating tool with a special profile is introduced at the interface of the materials to be joined and translated along the joint at controlled speeds. Heat generated softens the material and allows the tool to stir while traveling along the joint. This work aimed to product welds on AA 5052-H34 plates, 6.35mm (0,25 inches) thickness, using a conventional milling machine. In order to do that, three tool geometries were designed, manufactured and tested so as to define which welding parameters could generate the best results. Once these parameters were chosen, each tool produced three welds and their performance was evaluated. Transversal bending, tensile tests, micro-hardness measurements along the weld cross-section and macrographical analysis were carried out in order to assess weld properties. In addition, MIG welds were produced and subjected to the same test conditions. Considering yield stress as an efficiency parameter, all the tested tools presented similar results (around 80% of the base metal yield stress). However one of these tools showed inferior performance when considering elongation or transversal bend

  11. Avaliação da geometria de ferramenta e parâmetros do processo FSW na soldagem da liga de alumínio AA 5052 Process parameters and tool geometry evaluation in the FSW of AA 5052 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Tiago Valdameri Capelari

    2009-09-01

    Full Text Available A soldagem de ligas de alumínio sem degradação excessiva das propriedades originais do metal base apresenta-se como um obstáculo a ser superado pelas indústrias em seus processos de fabricação, uma vez que o alumínio tem sido usado cada vez de forma mais intensiva. Neste sentido, o processo de soldagem denominado Friction Stir Welding (FSW tem recebido atenção por suas potencialidades onde o aporte de calor deve ser minimizado ou quando metais dissimilares devem ser soldados. Neste processo, uma ferramenta de alta resistência mecânica e com um perfil especial é utilizada para, por meio de atrito com as peças a serem soldadas, gerar calor e misturar mecanicamente o material da junta, consolidando a solda. Este trabalho visa implementar o processo FSW utilizando uma fresadora universal de elevada rigidez na soldagem de chapas de alumínio AA 5052-H34 com 6,35mm de espessura. Para tanto, três geometrias de ferramentas de soldagem foram projetadas, fabricadas e testadas, de forma a definir-se parâmetros de soldagem compatíveis com as condições fornecidas pela máquina fresadora, por meio de testes preliminares. Definidos estes parâmetros, juntas foram obtidas com as três geometrias de ferramenta disponíveis e seus desempenhos foram comparados. Ensaios mecânicos de dobramento e tração, medição do perfil de microdurezas e análise macrográfica da seção transversal das soldas foram os métodos empregados na caracterização das propriedades resultantes. Em adição, soldas pelo processo MIG também foram obtidas e sujeitas às mesmas avaliações. considerando-se a tensão de escoamento como parâmetro de comparação, as três geometrias testadas apresentaram desempenho similar (em torno de 80% da tensão de escoamento do metal base. Porém, se comparadas com respeito aos valores de ductilidade ou aos testes de dobramento transversal, observou-se que uma das geometrias testadas tem desempenho inferior às demais devido a presença de uma descontinuidade longitudinal no cordão de solda. O perfil de microdureza das amostras soldadas pelo processo FSW demonstrou homogeneidade entre as diferentes zonas microestruturais existentes ao longo da seção transversal, ao passo que as amostras soldadas através do processo MIG apresentaram variação característica dos processos ao arco elétrico.Welding of aluminum alloys with no considerable degradation of the properties of the base metal is a problem to be overcomed by industry manufacturing processes. In the aeronautical industry, no-melt joining processes such as adhesive bonding or riveting are often considered when designing aluminum connections. Alternatively, a welding process named Friction Stir Welding (FSW is receiving crescent attention for its potential applications where heat input shall be minimized or when dissimilar metals must be joined. In this process a high strength rotating tool with a special profile is introduced at the interface of the materials to be joined and translated along the joint at controlled speeds. Heat generated softens the material and allows the tool to stir while traveling along the joint. This work aimed to product welds on AA 5052-H34 plates, 6.35mm (0,25 inches thickness, using a conventional milling machine. In order to do that, three tool geometries were designed, manufactured and tested so as to define which welding parameters could generate the best results. Once these parameters were chosen, each tool produced three welds and their performance was evaluated. Transversal bending, tensile tests, micro-hardness measurements along the weld cross-section and macrographical analysis were carried out in order to assess weld properties. In addition, MIG welds were produced and subjected to the same test conditions. Considering yield stress as an efficiency parameter, all the tested tools presented similar results (around 80% of the base metal yield stress. However one of these tools showed inferior performance when considering elongation or transversal bending test as a comparison parameter due

  12. A crystallographic texture perspective formability investigation of aluminium 5052 alloy sheets at various annealing temperatures

    International Nuclear Information System (INIS)

    Formability, an important mechanical property of the sheet metal is strongly reliant on the crystallographic texture. Consequently deep drawability is also influenced. This paper deals with the perspective of crystallographic texture and its relevance with the formability of AA 5052 aluminium alloy sheet of 2 mm thickness annealed at four different temperatures namely 200 deg. C, 250 deg. C, 300 deg. C and 350 deg. C. Forming limit diagrams determined and plotted experimentally, their crystallographic textures obtained and their ODF plots prepared by X-ray diffraction were analyzed. The Forming limit diagrams (FLDs) of AA 5052 sheets annealed under different temperatures were examined with respect to the crystallographic texture point of view. The FLDs and crystallographic textures were then correlated with normal anisotropy of the sheet metal. It was found that the formability of aluminium alloy AA 5052 annealed at 350 deg. C possessed good formability, optimal texture and high normal anisotropy value

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

    Directory of Open Access Journals (Sweden)

    Hasan GÖKKAYA

    2006-03-01

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

  14. SURFACE MELTING OF ALUMINIUM ALLOYS

    OpenAIRE

    Veit, S.; Albert, D.; Mergen, R.

    1987-01-01

    The wear properties of aluminium base alloys are relatively poor. Laser surface melting and alloying has proved successful in many alloy systems as a means of significantly improving the surface properties. The present work describes experiments designed to establish the scope of laser treatment of aluminium alloys. Aluminium does not absorb CO2 laser light as well as other metals which necessitated first a general study of absorption caotings. Aluminium alloys offer fewer opportunities than ...

  15. Soldering of aluminium alloys

    International Nuclear Information System (INIS)

    A literature survey about soldering in general and aluminium alloys soldering in particular is presented. The existing methods of soldering aluminium alloys are described. These include soldering with flux, soldering after preliminary plating, vacuum brazipressure and temperature (NTP), sample age calculation based on 14C half life of 5570 and 5730 years, age correction for NTP, dendrochronological corrections and the relative radiocarbon concentration. All results are given with one standard deviation. Input data test (Chauvenet's criterion), gas purity test, standard deviation test and test of the data processor are also included in the program. (author)

  16. Hydrogen generation from aluminium corrosion in reactor containment spray solutions

    International Nuclear Information System (INIS)

    The aluminium corrosion experiments in reactor containment spray solutions, under the conditions expected to prevail during LOCA in BWR and PWR, were performed in order to investigate relationships between temperature, pH and hydrogen production rates. In order to simulate the conditions in a BWR containment realistic ratios between aluminium surface and water volume and between aluminium surface and oxygen volume were used. Three different aluminium alloys were exposed to spray solutions: AA 1050, AA 5052 and AA 6082. The corrosion rates were measured for BWR solutions (deaerated and aerated) with pH 5 and 9 at 50, 100 and 1500C. The pressure was constantly 0.8 MPa. The hydrogen production rate was measured by means of gas chromatography. In deionized BWR water the corrosion rates did not exceed about 0.05 mm/year in all cases, i.e. were practically independent of temperature and pH. Hydrogen concentrations were less than 0.1 vol.% in cooled dry gas. Corrosion rates and hydrogen production in PWR alkaline solution measured at pH 9.7 and 1500C were very high. AA 5052 alloy was the best material

  17. Inhibition properties and adsorption behavior of imidazole and 2-phenyl-2-imidazoline on AA5052 in 1.0 M HCl solution

    International Nuclear Information System (INIS)

    Highlights: • IM and 2-PI show corrosion inhibition for AA5052 in HCl solution. • Synergistic effect between IM and 2-PI is observed and its mechanism is assumed. • Adsorption properties are estimated using ?Gads0, ?Hads0 and Ea, respectively. • Adsorption structures and inhibition mechanism for AA5052 are proposed. - Abstract: The inhibition behavior of imidazole (IM) and 2-phenyl-2-imidazoline (2-PI) for AA5052 was investigated by weight loss, electrochemical, contact angle measurements and scanning electron microscopy. The results show that IM and 2-PI can inhibit the corrosion of AA5052 and the inhibition efficiency of 2-PI is higher. The adsorption properties of them are estimated using ?Gads0, ?Hads0 and Ea. The results reveal that the adsorption processes are exothermic reactions mainly by a monolayer chemisorption mechanism, and follow Langmuir adsorption isotherm. The differences of the monolayer adsorption structure between IM and 2-PI on AA5052 surface are analyzed, and the inhibition mechanisms are proposed

  18. Recent developments in advanced aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Highlights: • To compete with composites, performance of aluminium alloys should be increased. • Al–Li alloys have higher strength, fracture and fatigue/corrosion resistance. • Improvements of aerospace Al alloys are due to optimised solute content and ratios. • In selecting new materials, there should be no reduction in the level of safety. • The use of hybrid materials could provide additional opportunities for Al alloys. - Abstract: Aluminium alloys have been the primary material for the structural parts of aircraft for more than 80 years because of their well known performance, well established design methods, manufacturing and reliable inspection techniques. Nearly for a decade composites have started to be used more widely in large commercial jet airliners for the fuselage, wing as well as other structural components in place of aluminium alloys due their high specific properties, reduced weight, fatigue performance and corrosion resistance. Although the increased use of composite materials reduced the role of aluminium up to some extent, high strength aluminium alloys remain important in airframe construction. Aluminium is a relatively low cost, light weight metal that can be heat treated and loaded to relatively high level of stresses, and it is one of the most easily produced of the high performance materials, which results in lower manufacturing and maintenance costs. There have been important recent advances in aluminium aircraft alloys that can effectively compete with modern composite materials. This study covers latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques. The mechanical properties on newly developed 2000, 7000 series aluminium alloys and new generation Al–Li alloys are compared with the traditional aluminium alloys. The advantages and disadvantages of the joining methods, laser beam welding and friction stir welding, are also discussed

  19. Shot peening of aluminium alloys

    International Nuclear Information System (INIS)

    Shot peening is a process of cold-hammering where a metallic surface is pelted with spherical grains. Each grain bumping into the surface acts as a hammer head and creates a small crater. The overlapping of these craters produces a residual compression layer just underneath the surface. It is well known that cracks cannot spread in a compression zone. In most cases of fatigue rupture and stress corrosion cracks propagate from the surface towards the inside so shot peening allows a longer lifetime of castings. Moreover most materials present a better resistance due to the cold-hammering effect of shot peening. Metallic surfaces can be treated in workshops or directly on site. Typical pieces that undergo shot peening on site are storing tanks, gas and steam turbines, tubes of steam generators and piping in oil or nuclear or chemical industries. This article describes shot peening from a theoretical and general point of view and presents the application to aluminium-lithium alloys. In the case of aluminium alloys shot peening can be used to shape the piece (peen-forming). (A.C.)

  20. Continuous casting of semisolid aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Motegi, Tetsuichi; Tanabe, Fumi; Sugiura, Eiji [Chiba Inst. of Tech., Dept. of Metallurgical Engineering, Tsudanuma, Narashino (Japan)

    2002-07-01

    In order to make up wrought Al-1.63mass%Si-0.54mass%Mg alloy billets for thixoforming and thixocasting, semisolid continuous casting was carried out. An inclined cooling plate was used to make numerous {alpha} aluminium crystal seeds which dispersed in the molten alloy before casting. Seeds of primary {alpha} aluminium crystals in the molten alloy grew in the tundish prior to entering the mould of the casting machine. (orig.)

  1. Alloys of uranium and aluminium with low aluminium content

    International Nuclear Information System (INIS)

    Uranium, as obtained after spinning in phase ?, presents an heterogeneous structure with large size grains. The anisotropic structure of the metal leads to an important buckling and surface distortion of the fuel slug which is incompatible with its tubular cladding for nuclear fuel uses. Different treatments have been made to obtain an isotropic structure presenting high thermal stability (laminating, hammering and spinning in phase ?) without success. Alloys of uranium and aluminium with low aluminium content present important advantage in respect of non allied uranium. The introduction of aluminium in the form of intermetallic compound (UAl2) gives a better resistance to thermal fatigue. Alloys obtained from raw casting present an improved buckling and surface distortion in respect of pure uranium. This improvement is obtained with uranium containing between 0,15 and 0,5 % of aluminium. An even more improvement in thermal stability is obtained by thermal treatments of these alloys. These new characteristics are explained by the fine dispersion of the UAl2 particles in uranium. The results after treatments obtained from an alloy slug containing 0,4 % of aluminium show no buckling or surface distortion and no elongation. (M.P.)

  2. Electron irradiation of dilute aluminium alloys

    International Nuclear Information System (INIS)

    Zone-refined aluminium and dilute alloys with silicon and indium have been irradiated inside a high voltage electron microscope. Interstitial dislocation loops nucleated and grew in all samples, but no voids could be observed. The precipitation of silicon was observed during irradiation. The effect of alloying on the loop growth rate is discussed. (author)

  3. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl

    Aluminium and its alloys are widely used in aerospace industry owing to their high strength to weight ratio. The surface of aluminium under normal conditions has a thin oxide film (2.5-10 nm) responsible for its inherent corrosion resistance. This oxide film can further be converted or transformed into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium is strictly regulated due to its toxic nature and suspected carcinogenicity. So, it is highly imperative to develop other alternatives for chrome conversion coatings. Treatment of aluminium with natural water at elevated temperatures results in the formation of different forms of aluminium oxide (?-AlO(OH) , Al(OH)3) depending on the preparation parameters/conditions. Moreover, with the knowledge of factors controllingfilm growth, composition and morphology, such oxide layers carry huge potential for practical applications. Pure aluminium (AA1090, 99.94 wt. %) and other aluminium alloy surfaces were exposed to high pressure steam produced by an autoclave at a temperature of 107 – 121 °C and pressure of 15 -17 psi for 10 minutes to produce a thin coating of aluminium oxide. The aim of this study is to understand the effect of high pressure steam with and without different chemical additives on surface morphology and growth of oxide film on different intermetallic particles and corrosion behaviour of such alloys.Surface morphology was observed by using FEG-SEM, EDX and FIB-SEM. Metal oxide surface characterization and compositional depth profiling were investigated by using XPS and GD-OES respectively. Potentiodynamic polarization measurements and acid salt spray testing were used to study corrosion behavior of the produced coatings.

  4. Intermetallic phase particles in 6082 aluminium alloy

    Directory of Open Access Journals (Sweden)

    M. Wierzbiñska

    2007-02-01

    Full Text Available Purpose: In the technical 6xxx Al alloys besides the intentional additions Mg i Si, transition metals andimpurities (Fe and Mn are always present. Even not large amount of these impurities causes the formation a newphase components. The exact composition of the alloy and casting condition will directly influence the selectionand volume fraction of intermetallic phases. During casting of 6xxx alloys, a wide variety of Fe-containingintermetallics phases Al-Fe, Al-Fe-Si and Al-Fe-Mn-Si are formed among the aluminium dendrites. The aim ofthis work was to examine the composition and morphology of complex microstructure of the intermetallics in6082 aluminium alloy.Design/methodology/approach: Light microscopy (LM, electron microscopy techniques (SEM and TEMin combination with X-ray analysis (SEM/EDS, and X-ray diffraction (XRD were used.Findings: The examinations of the as-cast alloy after slow solidification at a cooling rate 2°C/min reveal that themicrostructure consisted a wide range of intermetallics phases, namely: ß-Al5FeSi, ?-Al15(FeMn3Si, Al9Mn3Si,?-Al12Fe3Si, Mg2Si.Research limitations/implications: To facilitate confirmation of the achieved results it is recommended toexecute supplementary analysis of the aluminium alloys, 6xxx series in particular.Practical implications: Since the, what involves changes of alloy properties, From a practical position it isimportant to understand formation conditions of the intermetallics in order to control final components of thealloy microstructure. The importance of this is due to the fact that morphology, crystallography and chemicalcomposition of the intermetallics strongly affect the properties of the alloy.Originality/value: This work has provided essential data about almost all possible intermetallic phasesprecipitating in 6000 series aluminium alloys.

  5. Thixoforming of normally wrought aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, H.V.; Kapranos, P.; Liu, D.; Chayong, S.A.; Kirkwood, D.H. [Sheffield Univ. (United Kingdom). Dept. of Engineering Materials

    2002-07-01

    Thixoforming - or semi-solid processing - is the shaping of metal components in the semi-solid state. The commercial process uses casting alloys such as 356, 357 and A357 and millions of thixoformed automotive parts are produced with these alloys annually. The challenge is to extend thixoforming to higher performance alloys, which are normally wrought. There is growing evidence that the high strength wrought specification aluminium alloys can be successfully thixoformed, perhaps with some minor modifications to composition or indeed some tighter constraints in the bounds allowed in the alloy specification. Considerable development work is required but the prize will be a significant extension in the potential applications of thixoforming. In this paper some of the results obtained from an ongoing systematic study of thixoforming 2000 series, 6000 series and 7000 series alloys will be presented, along with mechanical properties of thixoformed materials. (orig.)

  6. Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Yuksel, Serkan

    2013-01-01

    Corrosion resistance of aluminium alloys is related to the composition and morphology of the oxide film on the surface of aluminium. In this paper we investigated the use of steam on the surface modification of aluminium to produce boehmite films. The study reveals a detailed investigation of the effect of vapour pressure, structure of intermetallic particles and thickness of boehmite films on the corrosion behaviour of aluminium alloys.

  7. FSW characterization of 6082 aluminium alloys sheets

    OpenAIRE

    Mroczka, K.; Pietras, A.

    2009-01-01

    Purpose: The purpose of the investigations was to elaborate a set of FSW parameters for connecting 6082 aluminium alloy sheets allowing to produce welds of highest strength.Design/methodology/approach: The FSW was tried at different speeds and at additional cooling. The welds microstructure was studied using optical and scanning electron microscopes. The mechanical properties of produced connections are discussed regarding their tensile test and microhardness measurements.Findings: The FSW we...

  8. Aluminium alloys containing iron and nickel

    International Nuclear Information System (INIS)

    The first part of this report addresses mechanism, kinetics and structure factors of aluminium alloys containing iron and nickel in water and high temperature steam. The studied alloys contain from 0.3 to 0.7 per cent of iron, and 0.2 to 1.0 per cent of nickel. Corrosion resistance and corrosion structure have been studied. The experimental installation, process and samples are presented. Corrosion structures in water at 350 C are identified and discussed (structure of corrosion products, structure of metal-oxide interface), and then in steam at different temperatures (350-395 C). Corrosion kinetics is experimentally studied (weight variation in time) in water at 350 C and in steam at different temperatures. Reactions occurring at over-heated steam (more than 400 C) are studied, and the case of welded alloys is also addressed. The second part addresses the metallurgical mechanism and processes influencing aluminium alloy resistance to corrosion by high temperature water as it appeared that separated phases protect the solid solution through a neighbourhood action. In order to avoid deep local corrosions, it seems necessary to multiply protective phases in an as uniform as possible way. Some processes enabling this result are described. They belong to conventional metallurgy or to powder metallurgy (with sintering and extrusion)

  9. The Mechanism of Dross Formation on Aluminium and Aluminium Magnesium Alloys

    OpenAIRE

    Impey, S. A.

    1989-01-01

    Metal loss is an unavoidable consequence of the large scale melting of aluminium and its alloys. The objective of such processing must be to minimise losses, both from an economic viewpoint and to ensure optimum quality of cast and wrought products. Aluminium losses during melting and casting are primarily due to the formation of dross, a mixture of oxide and melt. Many of the commercially important aluminium alloys contain appreciable levels of magnesium (up to 5%) which...

  10. Fluidity of Aluminium Foundry Alloys

    OpenAIRE

    Di Sabatino, Marisa

    2005-01-01

    The fluidity of an alloy plays a key role for the foundry and transport industries as it affects the quality and soundness of the cast products. Particularly, fluidity influences the reject rates, hence casting costs and the production of thinwalled, hence light components. Fluidity is a complex technological property and depends on many parameters. However, many aspects of this subject are still not fully understood. The motivation of the research presented in this doctoral thesis was, there...

  11. FSW characterization of 6082 aluminium alloys sheets

    Directory of Open Access Journals (Sweden)

    K. Mroczka

    2009-12-01

    Full Text Available Purpose: The purpose of the investigations was to elaborate a set of FSW parameters for connecting 6082 aluminium alloy sheets allowing to produce welds of highest strength.Design/methodology/approach: The FSW was tried at different speeds and at additional cooling. The welds microstructure was studied using optical and scanning electron microscopes. The mechanical properties of produced connections are discussed regarding their tensile test and microhardness measurements.Findings: The FSW welds, aside some zigzag lines connected probably with the incorporation of the surface oxides, were found to be devoid of any macro defects. The weld microstructure showed strong grain refining with the smallest of ~14 ?m located in their centre. The highest ultimate tensile strength of such connections of ~230 MPa was obtained for experiments performed at a linear velocity of 710 rpm, rate of rotation 560 mm/min and applied intensive cooling of the joined plates. The welds showed lowest hardness in the centre rising by ~20% at its sides. The friction stir welding connections retain plastic properties of 6082 aluminium alloy presenting ductile fracture.Research limitations/implications: In the further studies bending tests and transmission electron microscopy investigations are planned. Additionally, the stability of microstructure of the welds at higher temperature will be analysed.Practical implications: The elaborated parameters for FSW of 6082 welding can be applied as starting data for industry FSW tests for such alloy.Originality/value: The results of present experiments are adding new information on FSW of the aluminium alloys, especially 6082 type. The applied welding parameters provide good quality of welds.

  12. Solidification microstructures of aluminium-uranium alloys

    International Nuclear Information System (INIS)

    The solidification of microstrutures of aluminium-uranium alloys in the range of 4 to 20% uranium is investigated. The solidification was obtained both in ingot molds and under controlled directional solidification. The conditions for the presence of primary crystals and eutectic are discussed and an analysis of the influence of variables (growth rate and thermal gradient in the liquid) on the alloy structure is made. The effect of cooling rate on the alloy structures has been determined. It is found that the resulting structure can be derived from the kinectics concept, as required by the coupled-zone theory. Suggestions on the qualitative intervals of composition and temperatures with eutectic growth are presented

  13. Melt spun aluminium alloys for moulding optics

    Science.gov (United States)

    Gubbels, G.; Tegelaers, L.; Senden, R.

    2013-09-01

    Melt spinning is a rapid quenching process that makes it possible to create materials with a very fine microstructure. Due to this very fine microstructure the melt spinning process is an enabler for diamond turning optics and moulds without the need of post-polishing. Using diamond turning of melt spun aluminium one can achieve coating concept RSA-905 can be upgraded to a competitive alternative to steel in terms of price, performance and logistics. This paper presents some recent developments for improved mould performance of such concept. Hardness, wear resistance and adhesion are topics of interest and they can be applied by special coatings such as diamond-like carbon (DLC) and chromium nitride (CrN). These coatings make the aluminium alloy suitable for moulding mass production of small as well as larger optics, such as spectacle lenses.

  14. Aluminium Alloy Cast Shell Development for Torpedoes

    Directory of Open Access Journals (Sweden)

    Vijaya Singh

    2005-01-01

    Full Text Available The sand-cast aluminium alloy cylindrical shells were developed for the advanced experimental torpedo applications. The components had intricate geometry, thin-walled sections, and stringent property requirements. The casting defects, such as shrinkage, porosity, incomplete filling of thin sections, cold shuts, inclusions and dimensional eccentricity, etc were found inthe initial castings trials. improvements in casting quality were achieved through modified methodology, selective chilling, risering, and by introducing ceramic-foam filters in the gatingsystem. The heat-treated and machined components met radiographic class I grade C/E standards, mechanical properties to BS1490 specifications, and leakage and hydraulic pressure testrequirements relevant for such applications.

  15. Deviatoric response of the aluminium alloy, 5083

    Science.gov (United States)

    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.

  16. TEM microstructure investigations of aluminium alloys used for laser alloying

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2012-12-01

    Full Text Available Purpose: In this paper there are presented results of Transmission Electron Microscope investigation concerning the structure of the AlSi7Cu4 cast aluminium alloy using for alloying and remelting with the high power diode laser (HPDL. There are also presented the results of the thermo-derivative analysis performed using the UMSA (Universal Metallurgical Simulator and Analyser device, allowing to determine the specific points of the solidifying alloy, what is helpful for phase determination occurred in this alloy. In this work especially the changes of the precipitation type, size and shape were determined.Design/methodology/approach: The investigations were performed using electron microscopy for the microstructure and phases determination. By mind of the transmission electron microscopy, especially selected area diffraction method appliance it was possible to determine the phases occurred in the alloy in the as cast state. The morphology and size of the Mg2Si was also possible to determine as well the lattice parameters for this phase.Findings: : The reason of this work was also to present the laser treatment technology, which will be used for further alloying and remelting with ceramic powders – especially carbides and oxides. Particularly the overview will be directed on the laser power to achieve good layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in external conditions. The structure of the surface laser tray changes in a way, that there are very high roughness of the surface zone and the flatness or geometry changes in an important manner, crucial for further investigation.Research limitations/implications: The aluminium samples were examined metallographically using transmission electron microscope with different image techniques.Practical implications: Developing of new technology with appliance of Al alloys, High Power Diode Laser and diverse ceramic powders will be possible to obtain, based in findings from this research project. Some other investigation should be performed in the future, but the knowledge found in this research concerning the proper process parameters for each type of alloy shows an interesting investigation direction.Originality/value: The combination of metallographic investigation for cast aluminium alloys - including electron microscope investigation - and HPDL treatment parameters makes the investigation very attractive for automobile, aviation industry, and others where aluminium alloys plays an important role.

  17. Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys

    OpenAIRE

    Hamilta de Oliveira Santos; Marilene Morelli Serna; Nelson Batista de Lima; Isolda Costa; Jesualdo Luiz Rossi

    2005-01-01

    Aluminium-silicon alloys have been wide accepted in the automotive, electric and aerospace industries. Preferred orientation is a very common condition for metals and alloys. Particularly, aluminium induces texture during the forming process. The preparation of an aggregate with completely random crystal orientation is a difficult task. The present work was undertaken to analyse the texture by X-ray diffraction techniques, of three spray formed hypereutectic Al-Si alloys. Samples were taken f...

  18. Local electrochemical behaviour of 7xxx aluminium alloys:

    OpenAIRE

    Andreatta, F.

    2004-01-01

    Aluminium alloys of the 7xxx series (Al-Zn-Mg-Cu) are susceptible to localized types of corrosion like pitting, intergranular corrosion and exfoliation corrosion. This represents a limitation for the application of these alloys in the aerospace components because localized corrosion might have a negative effect on safety and costs. This PhD thesis investigates the relation between electrochemical behaviour and microstructure of a number of 7xxx aluminium alloys: AA7075, AA7349 and an experime...

  19. TITANIUM CARBON ALUMINIUM : A NOVEL GRAIN REFINER FOR ALUMINIUM-LITHIUM ALLOYS

    OpenAIRE

    Birch, M.; Cowell, A.

    1987-01-01

    This work explores the possibility of achieving grain size control in aluminium-lithium alloys with the titanium carbon aluminium (TiCAl) master alloys invented at the Technical University of Berlin and developed by London and Scandinavian Metallurgical Co Ltd (LSM). Grain refining tests were conducted on a single batch of 8090 alloy using addition rates of 0.2wt% and 0.4wt% of TiCAl and 3/1 titanium boron aluminium (TiBAl). Other tests using 0.4wt% of binary TiAl gave poor results, showing t...

  20. Disagglomeration in thixoformed wrought aluminium alloy 2014

    International Nuclear Information System (INIS)

    Thixoforming is a type of semi-solid metal processing, which involves the processing of alloys in the semi-solid state. Disagglomeration of solid globules during thixoforming of wrought aluminium alloy 2014 was investigated by electron back-scatter diffraction. The recrystallisation and partial melting route was used to produce the thixotropic feedstock for thixoforming. The starting material was commercially extruded wrought aluminium alloy 2014 in the T6 temper condition. The crystallographic orientations of the grains and misorientation between neighbouring grains were investigated in the starting material, isothermally heat-treated material (heat treated at temperatures up to 901 K to mimic the treatment which the thixoformed sample undergoes prior to forming) and in as-thixoformed material. The starting material showed strong {1 1 0} and {1 1 2} components, which were replaced by strong {1 0 0} texture during heat treatment. Thixoforming of the material almost completely randomised the texture, indicating that disagglomeration has occurred. About a quarter of the boundaries in the as-received material are low angle grain boundaries. This declines to about 18% in the heat-treated but the as-thixoformed misorientation data suggests a very high proportion of LAGBs. This is thought to be an artefact associated with the fact that the EBSD programme is attempting to resolve the microstructure within what was liquid and to allocate orientations withs liquid and to allocate orientations within that. The data do not represent the parameter which is sought viz. the misorientation between what were neighbouring solid spheroids in the semi solid state because these are now separated by solidified liquid. The data on misorientation in systems which have been semi-solid must therefore, be treated with circumspection

  1. Disagglomeration in thixoformed wrought aluminium alloy 2014

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [Department of Engineering, University of Leicester, University Road, Leicester LE17RH (United Kingdom); Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S13JD (United Kingdom); Atkinson, H.V. [Department of Engineering, University of Leicester, University Road, Leicester LE17RH (United Kingdom)]. E-mail: d1458@le.ac.uk; Higginson, R.L. [IPTME, Loughborough University, Loughborough LE113TU (United Kingdom)

    2005-02-15

    Thixoforming is a type of semi-solid metal processing, which involves the processing of alloys in the semi-solid state. Disagglomeration of solid globules during thixoforming of wrought aluminium alloy 2014 was investigated by electron back-scatter diffraction. The recrystallisation and partial melting route was used to produce the thixotropic feedstock for thixoforming. The starting material was commercially extruded wrought aluminium alloy 2014 in the T6 temper condition. The crystallographic orientations of the grains and misorientation between neighbouring grains were investigated in the starting material, isothermally heat-treated material (heat treated at temperatures up to 901 K to mimic the treatment which the thixoformed sample undergoes prior to forming) and in as-thixoformed material. The starting material showed strong {l_brace}1 1 0{r_brace}<3 2 2> and {l_brace}1 1 2{r_brace}<1 1 1> components, which were replaced by strong {l_brace}1 0 0{r_brace}<0 0 1> texture during heat treatment. Thixoforming of the material almost completely randomised the texture, indicating that disagglomeration has occurred. About a quarter of the boundaries in the as-received material are low angle grain boundaries. This declines to about 18% in the heat-treated but the as-thixoformed misorientation data suggests a very high proportion of LAGBs. This is thought to be an artefact associated with the fact that the EBSD programme is attempting to resolve the microstructure within what was liquid and to allocate orientations within that. The data do not represent the parameter which is sought viz. the misorientation between what were neighbouring solid spheroids in the semi solid state because these are now separated by solidified liquid. The data on misorientation in systems which have been semi-solid must therefore, be treated with circumspection.

  2. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  3. Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon

    OpenAIRE

    Tchotang, T.; Soh Fotsing, B. D.; Kenmeugne, B.; Anago, G. F.; Fogue?, M.; Nguena, E.

    2013-01-01

    This article is a comparative study of metallurgical characteristics of the different aluminium alloys gotten through recycling of recovered aluminium in Cameroon. A simple experimental device for the foundry of secondary aluminium blend, of very good quality built around a movable charcoal furnace is presented. It enables better energy efficiency, a better distribution of the heat around the crucible and indirectly assures good quality of the products obtained, while respecting the economic ...

  4. Cold rolling and lubricated wear of 5083 aluminium alloy

    International Nuclear Information System (INIS)

    The effect of cold deformation on the lubricated wear of 5083 aluminium alloy was investigated. SAE 10W was selected as liquid lubricant. The aluminium alloy was submitted to a cold rolling process, until the average thickness of the specimens was reduced by 7% and 15% respectively. From the experimental results obtained, the Stribeck curves for the as received and cold rolled aluminium alloy specimens were exacted. In all cases the three lubrication regimes were identified. In addition, the cold deformation process has led to a decrease of the friction coefficient of the tribosystem: 5083 aluminium alloy-410 stainless steel, for the same wear conditions (applied load, sliding speed and lubricant). The dominant wear mechanisms in each lubrication regime were studied via Scanning Electron Microscopy (SEM).

  5. Internal friction in iron-aluminium alloys having a high aluminium content

    International Nuclear Information System (INIS)

    By using a torsion pendulum to measure the internal friction of iron-aluminium alloys containing between 25 and 50 atom per cent of aluminium, it has been possible to show the existence of three damping peaks due to interstitial carbon. Their evolution is followed as a function of the carbon content, of the thermal treatment and of the aluminium content. A model based on the preferential occupation of tetrahedral sites is proposed as an interpretation of the results. A study of the Zener peak in these substitution alloys shows also that a part of the short distance disorder existing at high temperatures can be preserved by quenching. (author)

  6. Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Ivan Michalec

    2013-01-01

    Full Text Available Joining thin sheets of aluminium and its alloys is a promising area in the field of joining materials. Nowadays, joining methods that do not melt the material itself are increasingly being utilised. This paper deals with adhesive bonding of aluminium alloy A5754 by two-component epoxy resins. Theresults show that joints bonded by Hysol 9466 have appropriate mechanical properties, but that joints bonded by Hysol 9492 have better thermal stability.

  7. A study on the recycling of aluminium alloy 7075 scrap

    Energy Technology Data Exchange (ETDEWEB)

    Oezer, Goekhan [Yildiz Technical Univ., Yildiz (TR). Balkan Centre of Advanced Casting Technologies (BACAT); Marsoglu, Muezeyyen [Yildiz Technical Univ., Yildiz (Turkey). Dept. for Metal and Materials Science Engineering; Burgucu, Sarp

    2012-07-01

    Aluminium and its alloys have recently become an important metal whose area and amount of usage increase more and more, due to their mechanical properties, recycling ability, and penetrability. If it is considered that the bauxite, which is the raw material of aluminium is rare on earth, and also the area and amount of aluminium usage increases over time, the importance of aluminium recycling goes up. aluminium recycling has become crucial by means of both, the potential of the scrap's dependant increase on usage and the primary aluminium production, as it is providing energy and cost savings. 7xxx grades of scrap are collected with other scrap of aluminium alloys in one turn and recycled all together. As the regain of these alloys is not done by isolation of the various grades, the finally recycled ingots result in lower grades. High value aluminium scrap is regrettably not recovered, as it was anticipated. This study is dealing with 7075 aluminium alloys originated from discharged blow molding tools and the rest piece cuttings of blocks and plates. The material has been subjected to an induction furnace, and has been remelted into small ingots and hardened according to 7075 aluminium alloy parameters (hardening aluminium tooling). [German] Aluminium und seine Legierungen sind in den letzten Jahren aufgrund ihrer mechanischen Eigenschaften, ihrer Recyclingfaehigkeit und ihrer Durchlaessigkeit immer bedeutendere metallische Werkstoffe geworden. Unter Beruecksichtigung, dass Bauxit als Rohmaterial selten auf der Erde vorkommt und der Verbrauch mit der Zeit steigt, waechst die Bedeutung des Recyclings von Aluminium. Aluminiumrecycling, zumal es Energieund Kosteneinsparungen ermoeglicht, ist sowohl fuer die schrottabhaengigen Verwendungspotentiale und die PrimaerAluminiumproduktion gleichermassen bedeutend geworden. Die 7xxxx Schrottlegierungen werden in einem Arbeitsgang mit dem Schrott aus anderen Aluminiumlegierungen gesammelt und recycled. Da die Wiedergewinnung dieser Legierungen nicht nach isolierten Legierungstypen erfolgt, bestehen die schliesslich recycelten Barren aus niedrigeren Graden. Hochwertiges Aluminium wird bedauerlicherweise nicht wie vorgesehen wiedergewonnen. Dieser Beitrag behandelt Material, das entladenen Blasformteilwerkzeugen sowie Reststuecken aus Schnitten von Bloecken und Platten entstammt. Das Material wurde in einem Induktionsofen wieder in kleinen Gussstuecken zerschmolzen und entsprechend der ueblichen Parameter fuer die Aluminiumlegierung 7075 gehaertet (Aushaertung von Werkzeugen aus Aluminium).

  8. Effect of Fe and Si content in Aluminium Alloys as a result of increased recycling : Testing of high purity Aluminium Alloys in uniaxial tension

    OpenAIRE

    Slagsvold, Marius

    2011-01-01

    The recycling of aluminium from used aluminium scrap leads to an unavoidable presence of pollutions in the form of elements of various amounts. Two such elements are iron and silicon. These will always be present to some extent in an aluminium alloy as they are introduced to the alloy during processing. Iron and silicon are accumulative elements, meaning that they can never be completely eliminated once introduced into the aluminium. Some alloys have very narrow compositional windows, they ha...

  9. Computer modelling of age hardening for cast aluminium alloys

    International Nuclear Information System (INIS)

    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.

  10. Computer modelling of age hardening for cast aluminium alloys

    Science.gov (United States)

    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. Modelling of micro- and macrosegregation for industrial multicomponent aluminium alloys

    Science.gov (United States)

    Ellingsen, K.; Mortensen, D.; M'Hamdi, M.

    2015-06-01

    Realistic predictions of macrosegregation formation during casting of aluminium alloys requires an accurate modeling of solute microsegregation accounting for multicomponent phase diagrams and secondary phase formation. In the present work, the stand alone Alstruc model, a microsegregation model for industrial multicomponent aluminium alloys, is coupled with the continuum model ALSIM which calculates the macroscopic transport of mass, enthalpy, momentum, and solutes as well as stresses and deformation during solidification of aluminium. Alstruc deals with multicomponent alloys accounting for temperature dependent partition coefficients, liquidus slopes and the precipitation of secondary phases. The challenge associated with computation of microsegregation for multicomponent alloys is solved in Alstruc by approximating the phase diagram data by simple, analytical expressions which allows for a CPU-time efficient coupling with the macroscopic transport model. In the present work, the coupled model has been applied in a study of macrosegregation including thermal and solutal convection, solidification shrinkage and surface exudation on an industrial DC-cast billet.

  12. Forming limit diagram and void coalescence analysis of AA5052 coated with molybdenum-based ceramic nanocomposites

    International Nuclear Information System (INIS)

    Highlights: • Ceramic nanocomposite was coated using sputtering process. • Studies on fracture using double edge notch tensile geometry. • Adiabatic shear deformation are analyzed during tension. • The void coalescence analysis of ceramic nanocomposite carried. • Potential application in TBC in automobile, aerospace industries, etc. - Abstract: Aluminium 5052 alloy sheets of size 75 × 25 mm and 3 mm thickness with double edge semicircular notches of diameter from 2–8 mm have been coated with MoSi2–SiC nanocomposite coatings by sputtering process. The structural morphology of the ceramic coatings was explored by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The coated and uncoated sheet samples were subjected to tension–compression state of strain up to fracture by varying the notch sizes using INSTRON Universal Testing Machine (UTM). Fracture behaviour studies of the sheets were performed and forming limit diagram (FLD) was drawn. The void coalescence analysis was also carried out by using SEM images and the effect of coating behaviour of combined forming and fracture were analyzed. In the coated sheet, the L/W ratio was very close to 1.0. Thus, no oblate/prolate voids were observed and the heat generated during deformation was retained for longer time and thereby adiabatic shear band formation has occurred with increased formability

  13. Thermal and structure analysis of the aluminium alloy

    Directory of Open Access Journals (Sweden)

    Mariusz Król

    2015-05-01

    Full Text Available The microstructure that is attributable from the specific casting method dictates further mechanical and physical properties of the material. In order to understand how to control the microstructure of the casting, it is important to understand the changes in microstructure during crystallization. The work focused on thermal analysis, metallurgical characterization and laser treatment of an aluminium alloy. The research show that the thermal analysis carried out on UMSA Technology Platform is an efficient tool for collect and calculates thermal parameters. The paper contributes to better understanding non-equilibrium metallurgical characterization of aluminium alloys. The solidification of the aluminium dendritic network, iron containing intermetallic phases, the aluminium-silicon eutectic and magnesium containing intermetallic phases were characterized. 

  14. Mechanical Properties of Spray Cast 7XXX Series Aluminium Alloys

    OpenAIRE

    SALAMCI, Elmas

    2002-01-01

    Mechanical properties of spray deposited and extruded 7xxx series aluminium alloys were investigated in peak aged condition. To study the influence of Zn additions on the mechanical behaviour of spray deposited materials, three alloy compositions were selected, namely: SS70 (11.5% Zn), N707 (10.9% Zn) and 7075 (5.6% Zn). After ageing treatment, notched and unnotched specimens of spray deposited alloys were subjected to tensile tests at room temperature. Experimental results showed...

  15. Influência do superaquecimento nas variáveis térmicas de solidificação e na formação da microestrutura de ligas de alumínio / Overheating influence on solidification - thermal variables and microstructure formation of aluminium alloy

    Scientific Electronic Library Online (English)

    Jean Robert Pereira, Rodrigues; Tonnyfran Xavier de Araujo, Sousa; Ricardo Batista de, Andrade; Rezende Gomes dos, Santos; Mírian de Lourdes Noronha Motta, Mello.

    2009-12-01

    Full Text Available O objetivo do trabalho é o desenvolvimento de uma análise comparativa do processo de solidificação da liga de alumínio com diferentes taxas de superaquecimento. Os principais parâmetros de solidificação foram determinados experimentalmente afetados pelo grau de superaquecimento e sua influência na f [...] ormação da microestrutura. Foi escolhida a liga de AA5052 contendo 3% de magnésio pelo seu interesse comercial. A liga foi vazada com três diferentes graus de superaquecimento, em um dispositivo que permite a solidificação unidirecional e o monitoramento, através de um sistema de aquisição de dados, das variações de temperatura em diferentes posições da peça. A partir dos resultados de temperatura são determinados outros parâmetros do processo. Os espaçamentos interdendríticos são determinados a partir das micrografias. Através da análise experimental, é determinada a influência do grau de superaquecimento nos seguintes parâmetros relativos ao processo de solidificação: coeficiente de transferência de calor na interface metal/molde, velocidade de avanço da frente de solidificação, gradiente de temperatura em frente à isoterma liquidus, taxa de resfriamento, tempo local de solidificação e espaçamentos interdendríticos primário e secundário. Também é analisada a transição entre a estrutura colunar e equiaxial. Abstract in english A comparative analysis of the 5052 aluminum alloy solidification process involving different overheating ranges is presented herein. Experimentally determined, the main parametersof the solidification process were affected in the overheating range and influenced the microstructure arrangement. The 5 [...] 052 aluminium alloy was selected.It contains about 3% magnesium and is used for commercial purposes. The aluminium alloy was poured into a device that allows unidirectional solidification and was programmed with three different overheating ranges. Temperature variation at different sample positions was monitored using a data acquisition system. From the temperature results, the other parameters of the process were determined. The dendritic spacing was determined by the micrographs. Through experimental analysis, the influence of the overheating range was established at the following parameters related to the solidification process: the heat transfer coefficient at the metal/mold interface, the solidification rate, the thermal gradient at the liquidus isotherm, the cooling rate, the local solidification time and secondary arm spacing. The change between the columnar and equiaxed structure was also studied.

  16. Influência do superaquecimento nas variáveis térmicas de solidificação e na formação da microestrutura de ligas de alumínio Overheating influence on solidification - thermal variables and microstructure formation of aluminium alloy

    Directory of Open Access Journals (Sweden)

    Jean Robert Pereira Rodrigues

    2009-12-01

    Full Text Available O objetivo do trabalho é o desenvolvimento de uma análise comparativa do processo de solidificação da liga de alumínio com diferentes taxas de superaquecimento. Os principais parâmetros de solidificação foram determinados experimentalmente afetados pelo grau de superaquecimento e sua influência na formação da microestrutura. Foi escolhida a liga de AA5052 contendo 3% de magnésio pelo seu interesse comercial. A liga foi vazada com três diferentes graus de superaquecimento, em um dispositivo que permite a solidificação unidirecional e o monitoramento, através de um sistema de aquisição de dados, das variações de temperatura em diferentes posições da peça. A partir dos resultados de temperatura são determinados outros parâmetros do processo. Os espaçamentos interdendríticos são determinados a partir das micrografias. Através da análise experimental, é determinada a influência do grau de superaquecimento nos seguintes parâmetros relativos ao processo de solidificação: coeficiente de transferência de calor na interface metal/molde, velocidade de avanço da frente de solidificação, gradiente de temperatura em frente à isoterma liquidus, taxa de resfriamento, tempo local de solidificação e espaçamentos interdendríticos primário e secundário. Também é analisada a transição entre a estrutura colunar e equiaxial.A comparative analysis of the 5052 aluminum alloy solidification process involving different overheating ranges is presented herein. Experimentally determined, the main parametersof the solidification process were affected in the overheating range and influenced the microstructure arrangement. The 5052 aluminium alloy was selected.It contains about 3% magnesium and is used for commercial purposes. The aluminium alloy was poured into a device that allows unidirectional solidification and was programmed with three different overheating ranges. Temperature variation at different sample positions was monitored using a data acquisition system. From the temperature results, the other parameters of the process were determined. The dendritic spacing was determined by the micrographs. Through experimental analysis, the influence of the overheating range was established at the following parameters related to the solidification process: the heat transfer coefficient at the metal/mold interface, the solidification rate, the thermal gradient at the liquidus isotherm, the cooling rate, the local solidification time and secondary arm spacing. The change between the columnar and equiaxed structure was also studied.

  17. FACTORS INFLUENCING THE ENVIRONMENTAL BEHAVIOUR OF ALUMINIUM-LITHIUM ALLOYS

    OpenAIRE

    Gray, A.

    1987-01-01

    This paper discusses the microstructural features of aluminium-lithium alloys that influence their corrosion and stress corrosion behaviour. Emphasis has been given to the effect of microstructure on stress corrosion crack initiation and propagation in Al-Li-Cu-Mg-Zr alloys (e.g. 8090 and 8091). In particular, the use of both isothermal and duplex ageing routes to develop overaged microstructures with increased resistance to stress corrosion crack initiation has been assessed and significantl...

  18. Research about the properties of aluminium-lithium alloy

    International Nuclear Information System (INIS)

    The mechanical properties and microstructural characteristics of an aluminium-lithium alloy which also contains other elements such as copper, magnesium, zinc and zirconium has been investigated. This was done through optical and electron microscopy as well as mechanical testings and Auger spectroscopy analysis. The results have shown an embrittlement effect for the condition corresponding to aging heat treatments that give the highest resistance to this alloy. (author)

  19. Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys

    Directory of Open Access Journals (Sweden)

    Hamilta de Oliveira Santos

    2005-06-01

    Full Text Available Aluminium-silicon alloys have been wide accepted in the automotive, electric and aerospace industries. Preferred orientation is a very common condition for metals and alloys. Particularly, aluminium induces texture during the forming process. The preparation of an aggregate with completely random crystal orientation is a difficult task. The present work was undertaken to analyse the texture by X-ray diffraction techniques, of three spray formed hypereutectic Al-Si alloys. Samples were taken from a billet of an experimental alloy (alloy 1 and were subsequently hot-rolled and cold-rolled (height reduction, 72% and 70%, respectively. The other used samples, alloys 2 and 3, were taken from cylinders liners. The results from the Laue camera showed texture just in the axial direction of alloy 3. The pole figures also indicated the presence of a typical low intensity deformation texture, especially for alloy 3. The spray formed microstructure, which is very fine, hinders the Al-Si texture formation during mechanical work.

  20. Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys

    Scientific Electronic Library Online (English)

    Hamilta de Oliveira, Santos; Marilene Morelli, Serna; Nelson Batista de, Lima; Isolda, Costa; Jesualdo Luiz, Rossi.

    2005-06-01

    Full Text Available Aluminium-silicon alloys have been wide accepted in the automotive, electric and aerospace industries. Preferred orientation is a very common condition for metals and alloys. Particularly, aluminium induces texture during the forming process. The preparation of an aggregate with completely random cr [...] ystal orientation is a difficult task. The present work was undertaken to analyse the texture by X-ray diffraction techniques, of three spray formed hypereutectic Al-Si alloys. Samples were taken from a billet of an experimental alloy (alloy 1) and were subsequently hot-rolled and cold-rolled (height reduction), 72% and 70%, respectively. The other used samples, alloys 2 and 3, were taken from cylinders liners. The results from the Laue camera showed texture just in the axial direction of alloy 3. The pole figures also indicated the presence of a typical low intensity deformation texture, especially for alloy 3. The spray formed microstructure, which is very fine, hinders the Al-Si texture formation during mechanical work.

  1. Weldability of high strength aluminium-scandium alloys

    International Nuclear Information System (INIS)

    Australia possesses a significant percentage of the world reserves of the ores required for the production of light alloys such as aluminium, magnesium and titanium. However, most of these minerals deposits are exported for processing, losing the potential of value adding benefits. Scandium has been known for some time to possess excellent grain refining properties when alloyed with aluminium. Although this adds considerable benefits to the mechanical properties of these alloys, it has not been fully exploited due to the high cost of producing the scandium metal. Deposits of scandium containing ore have recently been identified in Australia that are far more accessible than other deposits throughout the world. CSIRO Manufacturing Science and Technology had initiated a research project to investigate the effect of scandium and other grain refining additions on the properties of selected aluminium alloys in order to develop the market and maximise the potential benefits from Australian resources. The major objective of the project is to develop high strength aluminum alloys that exhibit good processing characteristics, particularly good weldability

  2. Fatigue behaviour of 6061 aluminium alloy and its composite

    OpenAIRE

    Hwa, Ping

    2001-01-01

    Fatigue behaviour of an artificial aged powder metallurgy 6061 aluminium alloy, and a composite made of this alloy with 15% volume fraction of SiCp was investigated. The alloy was subjected to T6 heat treatment, as was the composite material chosen (which incorporated SiC particles of average size 30pm). An extensive experimental programme was carried out in which fatigue lives were determined using load-controlled axial loading of unnotched cylindrical samples, at stress ratios of-1 and 0.1....

  3. TEM microstructure investigations of aluminium alloys used as coating substrate

    Directory of Open Access Journals (Sweden)

    T. Ta?ski

    2013-01-01

    Full Text Available Purpose: The aim of this paper was investigated structure and properties of gradient coatings produced in PVD process on AlSi9Cu aluminium alloys.Design/methodology/approach: The following results concern the structures of the substrates and coatings with the application of electron transmission and scanning microscopy; phase composition of the coatings using X-ray diffraction and grazing incident X-ray diffraction technique (GIXRD; microhardness and wear resistance.Findings: The deposited coatings are characterized by a single, double, or multi-layer structure according to the applied layers system, and the individual layers are coated even and tightly adhere to the substrate as well to each other. The analysis of coatings obtained on the surface of cast aluminium alloys by the PVD processes show a clear - over 100% - increase of the microhardness, compared to the base material microhardness.Practical implications: Achieving of new operational and functional characteristics and properties of commonly used materials, including the Al-Si-Cu alloys is often obtained by heat treatment, ie, precipitation hardening and/or surface treatment due to application or manufacturing of machined surface layer coatings of materials in a given group of materials used for different surface engineering processes.Originality/value: The paper presents the research involving the PVD coatings obtained on an unconventional substrate such as aluminium alloys. Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The above mentioned requirements and expectations regarding the contemporary materials are met by the non-ferrous metals alloys used nowadays, including the aluminium alloys.

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

    CERN Document Server

    International Organization for Standardization. Geneva

    1996-01-01

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

  5. Deoxidation and alloying of magnetically hard alnico alloys with titanium and aluminium

    International Nuclear Information System (INIS)

    The effect of deoxidation and alloying with aluminium and titanium on the alnico alloys has been studied by subjecting cast specimens and sprayed specimens to metallographic, X-ray diffraction and differential thermal analyses. The alloy was found to contain aluminium oxides, titanium oxides, titanium nitrides as well as complex oxides - Al2O3xTiO2. Addition of titanium enhances the crystal lattice of the alloy promoting oxygen solubility. However due to the changing oxygen, titanium and aluminium activity, the oxygen content in alnico alloy is reduced. Titanium inhibits the alpha-solid solution extending its range and increases the strength and hardness. The concentration of effective electrons of conductivity is not increased thereby but remains constant at 1.86x1021 cm-3

  6. Shear bands in aluminium-lithium alloys

    International Nuclear Information System (INIS)

    The formation of shear bands in Al-Li alloys in cold rolling and their influence on mechanical properties of rolled and heat treated sheets are under consideration. It is shown that shear bands as well as the network of recrystallized grains along previous bands are undesirable structural constituents in aluminum alloy sheets as they decrease processing and operational properties of alloys. In further metal forming the localization of strain is observed along shear bands or zones of recrystallized grains. To avoid failure due to shear band formation it is recommended to roll alloys in as-annealed state and properly regulate reduction degree

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

    Science.gov (United States)

    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. PMID:20837560

  8. Positron annihilation observations of shot peened aluminium alloys

    International Nuclear Information System (INIS)

    Samples of two aluminium alloys, 7075 and 2024, were used to examine the damage caused by surface shot peening. The 7075 alloy was in the T6 condition, which significs solution heat treatment and artificial aging to maximum hardness. The 2024 alloy was in the T3 condition, which signifies solution heat treatment followed by cold work. 2024 - T3 is quite sensitive to positron measurements of damage when compared with 7075 - T6 alloy. The main reason for the intensitivity of the 7075 - T6 to positron measurements is very likely the presence of a fully developed state of precipitation hardening as denoted by the T6 coding. The cold work used in the T3 condition did not bring the 2024 - T3 alloy above the upper limit of detectability for positron trapping prior to peening

  9. Grain refinement of zinc-aluminium alloys

    International Nuclear Information System (INIS)

    It is now well-established that the structure of the zinc-aluminum die casting alloys can be modified by the binary Al-Ti or the ternary Al-Ti-B master alloys. in this paper, grain refinement of zinc-aluminum alloys by rare earth materials is reviewed and discussed. The importance of grain refining of these alloys and parameters affecting it are presented and discussed. These include parameters related to the Zn-Al alloys cast, parameters related to the grain refining elements or alloys and parameters related to the process. The effect of addition of other alloying elements e.g. Zr either alone or in the presence of the main grain refiners Ti or Ti + B on the grain refining efficiency is also reviewed and discussed. Furthermore, based on the grain refinement and the parameters affecting it, a criterion for selection of the optimum grain refiner is suggested. Finally, the recent research work on the effect of grain refiners on the mechanical behaviour, impact strength, wear resistance, and fatigue life of these alloys are presented and discussed. (author)

  10. Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon

    Directory of Open Access Journals (Sweden)

    T. Tchotang

    2013-07-01

    Full Text Available This article is a comparative study of metallurgical characteristics of the different aluminium alloys gotten through recycling of recovered aluminium in Cameroon. A simple experimental device for the foundry of secondary aluminium blend, of very good quality built around a movable charcoal furnace is presented. It enables better energy efficiency, a better distribution of the heat around the crucible and indirectly assures good quality of the products obtained, while respecting the economic constraints and users' safety. Six refining methods are proposed by the addition of polyvinyl chloride (method A, coke rich in carbon CHS (method C, ammonium chloride NH4Cl (method E, manganese dioxide MnO (method T, acrylic nitrite (C2H3Cln (method P and sodium chloride NaCl (method S. A critical analysis of the different recycling techniques is presented as well as a proposed process of melting and refining that enables the obtaining products with high degrees of purity. The results are then compared to the results obtained from the industrial methods of aluminium refining such as fractional crystallization (FC, granular filtration (GF and dissolution in a metal solvent (DS. The later (DS gives the rate of 6.540% of accumulated alloy elements and enables the best purification (93.460%, while the NaCl gives the lowest global rate of additive elements (9.478%, with the best purity index (90.522% amount the proposed methods. Results obtained show that this method of refining improves the metallurgical properties of secondary aluminium alloy blends and guarantees better safety, as well as reducing the risks of environmental pollution.

  11. Measurement of 63Ni in aluminium alloy samples

    International Nuclear Information System (INIS)

    In order to develop a new method of measuring 63Ni in aluminium alloy samples in reactor, the decontamination effect of the pretreatment and the relative questions of measuring 63Ni with the liquid scintillation counter were studied. In order to confirm decontamination factor, the corresponding impurity ions were measured after pretreated by joining some impurity ions to the aluminium alloy samples. Decontamination factor is more than 102 for every impurity ion. The correspond parameters of measuring 63Ni with the liquid scintillation counter were researched, including the acidity, the volume ratio of the sample and the scintillant liquid as well as the effect of the measure efficiency by joining Ni carrier. The standard deviation is 0.11. The relatively standard deviation is 15.9%. The detection limit of the method is 3.15 Bq/g. (authors)

  12. Viscous pressure bulging of aluminium alloy sheet at warm temperatures

    International Nuclear Information System (INIS)

    Improving the formability of aluminium alloy sheet metal by using warm or elevated temperature has become a valid approach. In this paper, viscous pressure bulging (VPB) at warm temperature is proposed. The coupled thermomechanical finite element method and experimental method were used to investigate the VPB of aluminium alloy AA3003 at warm temperature. The temperature distributions of sheet metal and viscous medium were analyzed for non-isothermal VPB. The influence of forming temperature on thickness distribution, forming load and failure location of sheet metal were investigated. Research results show the temperature gradient field in sheet metal forms when the initial temperature of viscous medium is lower than that of sheet metal. The formability and failure location of sheet metal changes with initial temperature of viscous medium

  13. Intermetallic phase particles in 6082 aluminium alloy

    OpenAIRE

    M. Wierzbiñska; G. Mrówka-Nowotnik; J. Sieniawski

    2007-01-01

    Purpose: In the technical 6xxx Al alloys besides the intentional additions Mg i Si, transition metals andimpurities (Fe and Mn) are always present. Even not large amount of these impurities causes the formation a newphase components. The exact composition of the alloy and casting condition will directly influence the selectionand volume fraction of intermetallic phases. During casting of 6xxx alloys, a wide variety of Fe-containingintermetallics phases Al-Fe, Al-Fe-Si and Al-Fe-Mn-Si are form...

  14. Cavitation-aided grain refinement in aluminium alloys:

    OpenAIRE

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditions of the stable grain refinement effect in different alloying systems; and (3) to apply the knowledge gained as a result of an experimental work on a small scale to direct chill (DC) casting proc...

  15. Grain boundary phenomena and failure of aluminium alloys

    OpenAIRE

    Haas, Marc-Jan de,

    2001-01-01

    In this thesis, grain boundary phenomena leading to intergranular failure of commercial aluminium alloys from the 6XXX- and 7XXX-series are investigated and explained. Both ductile and more brittle types of grain boundary fracture are considered. As the former type is very often related to precipitation of second phase particles at the grain boundary, a physical model is used in order to understand and quantify processes as grain boundary segregation and precipitation. The influence of the in...

  16. TEM microstructure investigations of aluminium alloys used as coating substrate

    OpenAIRE

    T. Ta?ski; K. Labisz; L.A. Dobrza?ski; M. Wi?niowski; Matysiak, W.

    2013-01-01

    Purpose: The aim of this paper was investigated structure and properties of gradient coatings produced in PVD process on AlSi9Cu aluminium alloys.Design/methodology/approach: The following results concern the structures of the substrates and coatings with the application of electron transmission and scanning microscopy; phase composition of the coatings using X-ray diffraction and grazing incident X-ray diffraction technique (GIXRD); microhardness and wear resistance.Findings: The deposited c...

  17. Emission properties of aluminium-lithium alloy

    International Nuclear Information System (INIS)

    High secondary emission properties at comparatively low operation temperatures were obtained when investigating aluminum-lithium alloy Al - 2.2 mass % Li. The maximal value of the coefficient of secondary electron emission for alloy, activated under optimal conditions, is achieved at comparatively low energy of primary electrons, equal to 600 eV. Low value of the first critical potential (15 ± 2 eV) was obtained. It is important for operation of secondary emission cathodes. 12 refs.; 4 figs

  18. LASER CLADDING ON ALUMINIUM BASE ALLOYS

    OpenAIRE

    Pilloz, M.; Pelletier, J.; Vannes, A.; Bignonnet, A.

    1991-01-01

    laser cladding is often performed on iron or titanium base alloys. In the present work, this method is employed on aluminum alloys ; nickel or silicon are added by powder injection. Addition of silicon leads to sound surface layers, but with moderated properties, while the presence of nickel induces the formation of hard intermetallic compounds and then to an attractive hardening phenomena ; however a recovery treatment has to be carried out, in order to eliminate porosity in the near surface...

  19. Machinability of magnesium and aluminium alloys. Part I: cutting resistance

    International Nuclear Information System (INIS)

    Aluminium (2.7 g/cm3) and magnesium (1.7 g/cm3) are two competing light metals with similar mechanical properties and excellent possibilities for recycling. The forming of magnesium is often seen as an impediment to its use. New forming techniques using magnesium shavings are being developed, particularly in Japan. The machining of magnesium alloys by removal of metal raises safety concerns (risk of fire), which limits many potential applications of magnesium. The purpose of this work is to clarify and compare the machining properties of these two types of metal and better understand the mechanisms that may explain the differences in behaviour. Such a comparison could eventually provide an estimate of the cost of producing shavings for the manufacture of aluminium and magnesium parts through forging and extrusion, which would limit environmental pollution. Based on an analysis of cutting resistance during machining, it was demonstrated that magnesium alloys are easier to machine than similar aluminium alloys. Magnesium shavings are shorter than those of 6061-T6, but are especially more regular than those of A356, and their size is independent of cutting speed. It was also demonstrated that the fragility of materials can be characterized based on the results of cutting resistance produced during drilling

  20. Grain refinement of Aluminium alloys using friction stir processing

    International Nuclear Information System (INIS)

    Full text.Friction Stir Processing (FSP) is a new advanced material processing technique used to refine and homogenize the microstructure of sheet metals. FSP is a solid state processing technique that uses a rapidly rotating non-consumable high strength tool steel pin that extends from a cylindrical shoulder. The rotating pin is forced with a predetermined load into the work piece and moved along with the work pieces, while the rotating pin deforms and stirs the locally heated material. It is a hot working process in which a large amount of deformation is imparted to the sheet. FS processed zone is characterized by dynamic recrystallization which results in grain refinement . this promising emerging process needs further investigations to develop optimum process parameters to produce the desired microstructure. In this work, we present preliminary results on the effects of rotational and translational speeds on grain refinement of AA5052. Under certain processing conditions, sub-micron grain structure was produced using this technique

  1. Production technology of zirconium and aluminium-zirconium master alloy

    International Nuclear Information System (INIS)

    India is endowed with vast deposits of zircon, which is the chief source material for zirconium in the country. With the launching of the atomic energy programme, research and development work was initiated at the Bhabha Atomic Research Center on various aspects of zirconium technology and a complete flowsheet has been developed for the processing of zirconium right from the mining and separation of zircon to metal production, alloying and fabrication of reactor components. work has also been carried out on the production of aluminium-zirconium master alloy and zirconium metal powder. The present paper describes briefly the entire flowsheet developed here for the production of reactor grade zirconium metal starting from Indian zircon. Production processes evolved for detonator grade zirconium metal powder and aluminum zirconium master alloy have also been dealt with

  2. Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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.

  4. Improvement in Wear Properties of a Hypereutectic Aluminium Silicon Alloy with Manganese

    Directory of Open Access Journals (Sweden)

    Prabhkiran Kaur

    2014-08-01

    Full Text Available Improvement in wear properties of rare earth Cerium base hypereutectic Aluminium-Silicon alloy with Manganese modification has been reported in this paper. Wear studies were carried out on cast samples of hypereutectic Aluminium-Silicon alloy (Al-Si with rare earth Cerium oxide (CeO2 and Manganese (Mn modification. Final wear properties of rare earth Cerium oxide and Manganese modified hypereutectic Aluminium Silicon alloy were compared with the values of author?s previous work on rare earth Cerium oxide modified hypereutectic Aluminium Silicon alloy and hypereutectic Aluminium Silicon base alloy. Rare earth Cerium oxide and Manganese modification in hypereutectic Aluminium Silicon base alloy reduced the wear rates as compared to rare earth Cerium oxide modified hypereutectic Aluminium Silicon alloy and hypereutectic Aluminium Silicon base alloy. A comparison of wear rates at same velocity, load and sliding distance was made between above three different conditions and it was observed that rare earth Cerium oxide and Manganese modified alloy performed with least wear rates. Wear rates for rare earth Cerium oxide and Manganese modified hypereutectic Aluminium Silicon alloy was 6.36 times lesser than wear rate of hypereutectic Aluminium Silicon base alloy and was 2.97 times lesser than rare earth Cerium oxide modified hypereutectic Aluminium Silicon alloy. Wear rates were also calculated for rare earth Cerium oxide and Manganese modified hypereutectic Aluminium Silicon alloy at various velocities ranging from 0.2 m/s to 1.0 m/s at an equal interval of 0.2 m/s. It was noticed that minimum wear occurred at 1.0 m/s velocity and maximum at 0.2 m/s velocity. Further, scanning electron micrographs (SEM of worn surfaces and wear debris of rare earth Cerium oxide and Manganese modified hypereutectic Aluminium Silicon alloy were compared at low velocity (0.2 m/s and high velocity (1.0m/s conditions at constant load (30 N and sliding distance (500 m. It was observed that worn surface and wear debris of rare earth Cerium oxide and Manganese modified hypereutectic Aluminium Silicon alloy, showed mild oxidative wear irrespective of lower velocity.

  5. Grain Refinement of Commercial EC Grade 1070 Aluminium Alloy for Electrical Application

    OpenAIRE

    Hassanabadi, Massoud

    2015-01-01

    The aluminium alloys for electrical conductivity applications are generally not grain refinedsince the addition of grain refiners drops the electrical conductivity by introducing impuritiesinto the melt. Non-grain refined aluminium may lead to bar fracture and cracks during themetalworking process. The present study focuses to find an optimum balance between the grain refiner addition andthe electrical conductivity of commercial EC grade 1070 aluminium alloy for electricalapplication. In orde...

  6. Subgrain Growth, Recovery Kinetics and Nucleation of Recrystallization of Cold Deformed Aluminium Alloys

    OpenAIRE

    Bunkholt, Sindre

    2013-01-01

    Phenomena related to annealing of aluminium alloys are among the least understood in aluminium metallurgy but very important for industrial thermo-mechanical processing i.e. deformation and annealing. Physical models are used to predict recovery and recrystallization behaviour, and associated material properties, industrially. However, alloy development, e.g. to incorporate more recycled aluminium, has shown that current softening models are not satisfactory. Thus, improvements do require a b...

  7. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    International Nuclear Information System (INIS)

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl3. A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl3 is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl5 and UCl6. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

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

    Science.gov (United States)

    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.

  9. Deviatoric Response of AN Armour-Grade Aluminium Alloy

    Science.gov (United States)

    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.

  10. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  11. Friction stir welding of 6061 aluminium alloy

    International Nuclear Information System (INIS)

    6061 AA (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance such as marine frames, pipelines, storage tanks, and aircraft components [1]. It is also used for the manufacturing of fuel elements in the nuclear research reactors. Compared to many of the fusion welding processes that are routinely used for joining structural alloys, friction stir welding (FSW) is a solid state joining process in which the material that is being welded is not melted and recast [2]. The welding parameters such as tool rotational speed, welding traverse speed, and tool profile play a major role in deciding the weld quality. Several FSW tools (differ from each other in pin angle, shoulder diameter, and shoulder concavity) have been used to fabricate a number of joints in order to obtain a tool with which a sound weld can be produced. It was found that the FSW tool with tapered cone pin, concave shoulder, and shoulder diameter equal to four times the welded plate thickness is suitable to produce a sound weld. The effect of the traverse speed on the global and local tensile properties of friction stir welded joints has been investigated in the 6061-T6 AA. The global tensile properties of the FSW joints were improved with increasing the traverse speed at constant rotation rate. It is found that the global tensile strength of the FSW joint is limited by the local tensile strength of themited by the local tensile strength of the nearest region to the weld center at which the cross section is composed mainly of the HAZ. The effect of the initial butt surface on the formation of the zigzag line on the tensile properties of the welds was examined by using three types of welding samples differ in the preparation of the initial butt surface. The first type of samples welded without removing the oxide layer from the initial butt surface (uncleaned butt surfaces joint). In the second type of samples the oxide layer was removed from the butt surfaces before welding (cleaned butt surfaces joint). In the third type of samples there was no initial butt surface (stirred joint). The zigzag line appears only within the cross section of the uncleaned butt surface joints, and no zigzag line observed within the cross section of the cleaned butt surface joints or the stirred joints. The three types of welds exhibited similar tensile properties, so the zigzag line has no effect on the tensile properties in the as welded condition

  12. Modelling technological properties of commercial wrought aluminium alloys

    International Nuclear Information System (INIS)

    The purpose of this paper is to model three important technological properties for aluminium alloys, based on their performance indices. The models are based on the chemical compositions and microstructure characteristics which are calculated using thermodynamical calculations. The properties that were modelled are the general corrosion, the weldability (MIG and TIG) and the machinability. The results from these models are to be used in materials selection and optimisation. The models clearly show that the general corrosion resistance is reduced for all alloy additions, except for small amounts of titanium. The largest influence on the corrosion is from copper and zinc. The weldability is negatively influenced by the copper and zinc-content, and for small additions of zirconium and titanium it is increased. The machinability is positively influenced by the hardness of the alloy or by adding lead or bismuth. For the non-heat-treatable alloys there was no influence from the composition to the corrosion resistance or the weldability. Copper and zinc which are added to increase the strength to the alloy strongly reduce both the weldability and the corrosion resistance but due to the increase in hardness increase the workability.

  13. Anisotropy and Inhomogeneity in Extrudates of Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    K. Macek

    2000-01-01

    Full Text Available Anisotropy and inhomogeneity of mechanical properties and texture of microstructure originating in hot extrusion process depend not only on the type of the alloy, state of the billet and extrusion parameters, but also on the shape and size of extrudates. Tensile properties in longitudinal and transversal directions of model extrudates having simple cross-sections have been tested on four types of aluminium alloys. Values of ultimate strength and yield stress in longitudinal direction are higher up to 100 MPa as compared to those in transversal direction, whereas differences in elongation are small. Pronounced anisotropy and inhomogeneity of mechanical properties have been detected in cross-sections of the model extrudates. Quantitative metallography was used for determination of subgrain size, specific number of intermetallic phases, volume fraction of recrystallized grains and for assessment of metallographic texture. Certain implications for the die design based on obtained results are finaly presented.

  14. Frictional conditions between alloy AA6060 aluminium and tool steel

    Science.gov (United States)

    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.

  15. Frictional conditions between alloy AA6060 aluminium and tool steel

    International Nuclear Information System (INIS)

    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. Image analysis used for aluminium alloy microstructure investigation

    Directory of Open Access Journals (Sweden)

    M. Krupi?ski

    2010-09-01

    Full Text Available Purpose: In this work the metallographic microstructure analysis of the investigated AlSi7Cu3Mg aluminium cast alloy was performed for samples cooled with different cooling rate settings. The preformed investigations are subjected to the analysis of cooling rate influence on the phase morphology.Design/methodology/approach: The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The influence of the cooling rate on the alloy microstructure was investigated using computer aided image analysis, in this work also the content of particular phases was analysed, as well the percentage of pinholes compared to the chosen cooling rate.Findings: The treated sample is without holes, cracks and defects as well as has a slightly higher hardness value compared to the as-cast material.Research limitations/implications: The investigated samples were made of the cylindrical shape and were cooled in the range of 0.2°C/s to 1.25°C/s. In this work also the derivative thermoanalysis was performed to determine the correlation between the chosen cooling rate and the microstructure as well changes in the derivative curve shape. For alloy cooling with chosen cooling rate as well for the derivative thermo-analysis the UMSA analysator was applied.Practical implications: The investigated material can find its use in the foundry industry; an improvement of component quality depends mainly on better control over the production parameters.Originality/value: The originality of this work is based on applying of regulated cooling rate of aluminium alloy for structure and mechanical properties changes. As an effect of this study it will be possible to understand and to influence the mechanism of structure forming, refinement and nucleation. Also a better understanding of the thermal characteristics will be provided to achieve a desirable phase morphology required for application of this material under production conditions.

  17. Study of interaction between VT-6 titanium alloy and an aluminium base alloy forming a composite

    International Nuclear Information System (INIS)

    Results of investigation of interaction processes of a metal melt on the aluminium base (LK4-1) with a hard alloy on the titanium base (VT-6) are presented. It is shown that in the 750-850 deg C range titanium is dissolved in the aluminium melt with the following production of titanium aluminides in the reaction zone. The conclusion is made on the formation mechanism of the reaction zone. The coefficients of diffusion and activation energy of the zone formation processes are given. It is shown that at small dimensions of the reaction zone strong bond between the composition components is formed

  18. Characterization and structure of precipitates in 6xxx Aluminium Alloys

    Science.gov (United States)

    Holmestad, Randi; Bjørge, Ruben; Ehlers, Flemming J. H.; Torsæter, Malin; Marioara, Calin D.; Andersen, Sigmund J.

    2012-07-01

    Solute atom nanoscale precipitates are responsible for the favourable mechanical properties of heat treatable aluminium alloys such as Al-Mg-Si (6xxx). The shape, structure and strengthening properties of age-hardening precipitates depend on alloy composition and thermo-mechanical history. We seek an improved understanding of the physics related to nucleation and precipitation on the atomistic level in these alloys. Once these mechanisms are sufficiently well described and understood, the hope is that 'alloy design' simulations can assist tailoring of materials with desired properties. In pure Al-Mg-Si we have determined the structure of nearly all the known metastable precipitate phases, by combining advanced TEM techniques (such as high resolution TEM and nano-beam diffraction) with atom probe tomography and density functional theory. We are now studying effects of additions /substitutions of Cu, Ag and/or Ge that promote formation of more disordered precipitates, employing aberration corrected high angle annular dark field scanning TEM. We find that all metastable precipitates contain variations of a widely spaced 'Si/Ge network'. In spite of disorder or defects, this network is surprisingly well ordered, with hexagonal projected sub-cell dimensions a = b ? 0.4 nm and c (along the fully coherent precipitate main growth direction) equal to 0.405 nm or a multiple of it.

  19. Characterization and structure of precipitates in 6xxx Aluminium Alloys

    International Nuclear Information System (INIS)

    Solute atom nanoscale precipitates are responsible for the favourable mechanical properties of heat treatable aluminium alloys such as Al-Mg-Si (6xxx). The shape, structure and strengthening properties of age-hardening precipitates depend on alloy composition and thermo-mechanical history. We seek an improved understanding of the physics related to nucleation and precipitation on the atomistic level in these alloys. Once these mechanisms are sufficiently well described and understood, the hope is that 'alloy design' simulations can assist tailoring of materials with desired properties. In pure Al-Mg-Si we have determined the structure of nearly all the known metastable precipitate phases, by combining advanced TEM techniques (such as high resolution TEM and nano-beam diffraction) with atom probe tomography and density functional theory. We are now studying effects of additions /substitutions of Cu, Ag and/or Ge that promote formation of more disordered precipitates, employing aberration corrected high angle annular dark field scanning TEM. We find that all metastable precipitates contain variations of a widely spaced 'Si/Ge network'. In spite of disorder or defects, this network is surprisingly well ordered, with hexagonal projected sub-cell dimensions a = b ? 0.4 nm and c (along the fully coherent precipitate main growth direction) equal to 0.405 nm or a multiple of it.

  20. Precipitation kinetics in a severely plastically deformed 7075 aluminium alloy

    International Nuclear Information System (INIS)

    In this paper we report a quantitative study, using small-angle X-ray scattering, of the precipitation kinetics during ramp heating and isothermal ageing in an AA7075 aluminium alloy processed by high-pressure torsion. The precipitation behaviour has been compared with that of the same material processed in a conventional manner and observations are supplemented by transmission electron microscopy for precipitate and grain size characterization using automated crystal orientation mapping. After severe plastic deformation and natural ageing, the material is shown to contain a high density of GP zones. During ageing, the precipitate size distribution becomes bimodal, with small precipitates behaving similarly to those of the conventionally processed material and large ones associated with the crystalline defects and reaching large sizes at considerably lower temperatures and shorter times as compared to the conventionally processed material

  1. Cold Spray Deposition of Titanium onto Aluminium Alloys

    Scientific Electronic Library Online (English)

    M., Barbosa; N., Cinca; S., Dosta; J. M., Guillemany.

    2010-06-01

    Full Text Available A liga de alumínio 7075-T6 é amplamente utilizada na aeronáutica devido à sua elevada relação resistência mecânica/peso. Porém está sujeita a diversas formas de corrosão resultantes dos diferentes ambientes em que se encontra inserida. Uma possível solução para melhorar o comportamento desta liga em [...] situações de corrosão é o seu revestimento com uma camada de titânio puro. Porém, uma vez que o titânio é um metal extremamente sensível à oxidação, a sua deposição no estado puro encontra-se limitada a processos como a Electrodeposição, Chemical Vapour Deposition ou Vacuum Plasma Spray, que são técnicas lentas e dispendiosas. Este trabalho propõe a deposição deste metal num substrato de alumínio 7075 através de uma tecnologia inovadora de deposição a frio conhecida como Cold Spray. A influência de diferentes parâmetros de deposição é estudada (temperatura e pressão do gás de processo, velocidade de alimentação do pó) e foi possível obter um revestimento de titânio puro superior a 300µm, de forma rápida e fácil, sem quaisquer alterações microestruturais. Após optimização dos parâmetros de deposição, o processo de Cold Spray, quando comparado às técnicas de projecção térmica convencional, permite obter revestimentos com boas propriedades mecânicas de forma rápida e económica, tornando-o ideal para aplicações industriais. Abstract in english The aluminium alloy 7075-T6 is widely used in aeronautic engineering due to its high mechanical resistance to weight ratio. Depending upon the environmental conditions, many types of corrosion mechanisms have been found to occur in aircraft structural aluminium alloys. A possible solution to improve [...] the alloy’s behaviour is the deposition of a pure Titanium coating. At present the deposition of Titanium is limited to processes such as Electroplating, Chemical Vapour Deposition and Vacuum Plasma Spray. These traditional approaches are generally slow and expensive, while the common thermal spray processes have two major limitations which are the presence of porosity and oxides in the spray-deposited material. Since Titanium is a metal very sensitive to oxidation, it is proposed in the present work to deposit it onto Aluminium substrates by a novel thermal spray process known as “Cold Spray”. In this work, the influence of the gas pressure and temperature, and the powder feeding rate on the cold spray process and in the final coating characteristics was studied, and a dense pure titanium coating onto aluminium 7075 substrates, with thickness higher than 300µm and no microstructural changes was easily and fast obtained. It was possible to conclude that after optimization, the cold spray process when compared to the conventional thermal spray techniques, results in coatings with very good properties and cost-time effective (higher coating thickness can be achieved in less time and with less money investment), making it ideal for industrial applications.

  2. Peculiar features of structural transformations in fusion zone of welded joints of aluminium-beryllium alloys

    International Nuclear Information System (INIS)

    Reasons of beryllium redistribution in the fusion zone of welded joints of aluminium-beryllium alloys are considered. The leading role of thermal diffuson in the enrichment with beryllium of sections adjacent to the joint is substantiated

  3. Machinability of magnesium and aluminium alloys. Part II: formation of shavings

    International Nuclear Information System (INIS)

    This work compares the methods of forming shavings during the machining of magnesium and aluminium alloys. The microstructural analysis of shavings explains the phenomena observed during machining. It has been confirmed that the shearing angle during machining of magnesium alloys is greater than that obtained with aluminium alloys. This also confirms the ductile/fragile behaviour of these two materials, the effects of which are seen in cutting resistance. Shavings obtained during drilling of magnesium alloys are shorter than those of 6061-T6, but are especially more regular than those of A356, and their size is independent of cutting speed. All of these results explain the major difference in behaviour of these two types of material: magnesium alloys are clearly easier to machine than aluminium alloys

  4. On the friction stir welding of aluminium alloys EN AW 2024-0 and EN AW 5754-H22

    OpenAIRE

    Ozarpa, C.; Ogur, A.; Cam, G.; Vural, M.

    2007-01-01

    Purpose: Purpose of this paper is investigate the friction stir welding capability of the EN AW 2024-0 and EN AW 5754-H22 Al alloys are studied, because two aluminium alloys are widely used in the industry and friction stir welding is getting widened to be used to join the aluminium alloys.Design/methodology/approach: Friction stir welding (FSW) is a new solid fhase technique invented and patented for aluminium alloys. EN AW 2024-0 and EN AW 5754-H22 are aluminium alloys can be welded...

  5. Inhibition effect of cerium in hybrid sol–gel films on aluminium alloy AA2024

    OpenAIRE

    Paussa, L.; Rosero-navarro, Nataly Carolina; Andreatta, F.; Castro, Y.; Dura?n, A.; Aparicio, M.; Fedrizzi, L.

    2009-01-01

    Aluminium alloys such as AA2024 are susceptible to severe corrosion attack in aggressive solutions (e.g. chlorides). Conversion coatings, like chromate, or rare earth conversion coatings are usually applied in order to improve corrosion behaviour of aluminium alloys. Methacrylate-based hybrid films deposited with sol–gel technique might be an alternative to conversion coatings.Barrier properties,paint adhesion andpossibly self-healing ability are important aspects for replacement o...

  6. A review of friction stir welding of AA 6061 aluminium alloy

    OpenAIRE

    Bhanodaya Kiran Babu, N.; Prabhu Kumar, A.; Joseph Davidson, M.

    2011-01-01

    This paper discuss about the friction stir welding of joining heat treatable aluminium alloys for aerospace and automobile industries. These welded joints have higher tensile strength to weight ratio and finer microsturcture. FSW of aluminium alloys have the potential to hold good mechanical and metallurgical properties. The aim of this study was to investigate the effect of process parameters on the tensile strength of the welded joints.

  7. Numerical Simulation and Experimental Verification of Upsetting Temperature Optimization of Aluminium Alloy

    OpenAIRE

    Maros Martinkovic; Maria Kapustova

    2012-01-01

    Warm forming of metal materials represents a profitable method of precise forming pieces production due to energy and time savings, obtaining of higher surface quality and dimension precision of forming pieces in comparison with hot forming. An optimal forming temperature was selected from experimental measurement of mechanical properties, plasticity and workability of an aluminium alloy. Upsetting forming process of aluminium alloy AlSiMg type was simulated using finite element method at war...

  8. A review of friction stir welding of AA 6061 aluminium alloy

    Directory of Open Access Journals (Sweden)

    N. Bhanodaya Kiran Babu

    2011-04-01

    Full Text Available This paper discuss about the friction stir welding of joining heat treatable aluminium alloys for aerospace and automobile industries. These welded joints have higher tensile strength to weight ratio and finer microsturcture. FSW of aluminium alloys have the potential to hold good mechanical and metallurgical properties. The aim of this study was to investigate the effect of process parameters on the tensile strength of the welded joints.

  9. Corrosion Inhibitive Effect of Ocimum Gratissimum Extract on Zinc - Aluminium Alloy in Hydrochloric Acid

    OpenAIRE

    Nkiko, Mojisola O.; Bamgbose, Janet T.

    2011-01-01

    The inhibitive effect of Ocimum gratissimum by seed extract on the corrosion of zinc - aluminium (ZA) alloy in 2 M hydrochloric acid (HCl) solution has been studied using gravimetric methods. Inhibition increases with concentration of extract but decreases with temperature. This observation implies that Ocimum gratissimum seed extract is an effective and non toxic inhibitor of the corrosion of zinc - aluminium alloy. Adsorption of the extract on the surface obeyed the Freundlich adsorption is...

  10. Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode

    International Nuclear Information System (INIS)

    This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

  11. The effect of surface treatment and gaseous rust protection paper on the atmospheric corrosion stability of aluminium alloy

    International Nuclear Information System (INIS)

    The experimental results of atmospheric corrosion of 166 aluminium alloy of Al-Mg-Si-Cu system and 167 aluminium alloy of Al-Mg-Si-Cu-Fe-Ni system for different surface treatment and different wrapping papers used are introduced. The results show: 1. The composition of aluminium alloy has some effect on the performance of atmospheric corrosion stability and the local corrosion depth for 167 aluminium alloy specimen is considerable. 2. After 8 years storage, the 167 aluminium alloy tubular specimen, which was treated with surface treatment in deionized water at 100 ? 230 C degree, has no spot of atmospheric corrosion found. 3. Within the test period, the performance of atmospheric corrosion stability by sulphuric-acid anodization film is remarkable. 4. The No. 19 gaseous rust protection paper has no effect of atmospheric corrosion stability on the 166 and 167 aluminium alloys which were treated with quenching and natural ageing method

  12. Intercorrelation of surface free energy and anode capacity of aluminium alloy anodes

    International Nuclear Information System (INIS)

    Surface free energies have been evaluated from Young's moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ? 1.47 % Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ? 0.08 mA/cm2 current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surfacefiree energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum. (Author)

  13. Directionality in the Mechanical Properties of Spray Cast and Extruded 7XXX Series Aluminium Alloys

    OpenAIRE

    SALAMCI, Elmas

    2003-01-01

    Three 7xxx series aluminium SS70, N707 and 7075 alloys have been produced by the spray deposition process. The alloys were extruded and subsequently heat treated in the T6 and T7 temper conditions. Texture analysis of as-received and solution treated alloys revealed and fibre textures leading to higher mechanical properties in the longitudinal direction. Anisotropic behaviour was observed in these alloys. In addition, the influence of recrystallizing, heat treatment, stretching, ...

  14. Determination of ultratrace amounts of uranium and thorium in aluminium and aluminium alloys by electrothermal vaporization/ICP-MS

    International Nuclear Information System (INIS)

    A method has been developed for determining the 0.01 ng g-1 level of uranium and thorium in aluminium and aluminium alloys by electrothermal vaporization (ETV)/ICP-MS. This method was found to be significantly interfered with any matrices or other elements contained. An ion-exchange technique was therefore applied to separate uranium and thorium from aluminium and other elements. It was known that uranium are adsorbed on an anion-exchange resin and thorium are adsorbed on cation-exchange resin. However, aluminium and copper were eluted with 6 M hydrochloric acid. Dissolve the sample with hydrochloric acid containing copper which was added for analysis of pure aluminium, and oxidize with hydrogen peroxide. Concentration of hydrochloric acid in the solution was adjusted to 6 M, and then passed the solution through the mixed ion-exchange resin column. After the uranium and thorium were eluted with 1 M hydrofluoric acid-0.1 M hydrochloric acid, the solution was evaporated to dryness. It was then dissolved with 1 M hydrochloric acid. Uranium and thorium were analyzed by ETV/ICP-MS using tungsten and molybdenum boats, respectively, since the tungsten boat contained high-level thorium and the molybdenum boat contained uranium. The determination limit of uranium and thorium were 0.003 and 0.005 ng g-1, respectively. (author)

  15. Development of Al-TiC Alloys Using Powder Metallurgy as Grain Refiners for Aluminium and Its Alloys

    OpenAIRE

    Omran, Abdel-nasser M.

    2014-01-01

    Al-Ti-C master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-Ti-C master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3), 5(4), 6.25(5) and 7.5(6) Wt% TiC(Wt% Ti). The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 oC in a tube furnace u...

  16. Potentiodynamic study of alloys of aluminium-vanadium and aluminium-niobium systems

    International Nuclear Information System (INIS)

    The study of the effect of transition metals on corrosion-electrochemical behaviour of aluminium in a neutral medium in potentiodynamic regime is continued. The investigations were carried out in the medium of 3 % sodium chloride solution. It is shown that aluminium doping by small additions of vanadium (up to 5 %) does not impair its electrochemical characteristics and corrosion stability and doping with niobium decreases the rate of aluminium corrosion by a factor of 2-3

  17. Elastic and plastic properties of iron-aluminium alloys. Special problems raised by the brittleness of alloys of high aluminium content

    International Nuclear Information System (INIS)

    The present study embodies the results obtained with iron-aluminium alloys whose composition runs from 0 to nearly 50 atoms per cent aluminium. Conditions of elaboration and transformation have been studied successively, as well as the Young's modulus and the flow stress; the last chapter embodies, a study of the Portevin-le-Chatelier effect in alloys of 40 atoms per cent of aluminium. I) The principal difficulty to clear up consisted in the intergranular brittleness of ordered alloys; this brittleness has been considerably reduced with appropriate conditions of elaboration and transformation. II) The studies upon the Young's modulus are in connection with iron-aluminium alloys; transformation temperatures are well shown up. The formation of covalent bonds on and after 25 atoms per cent show the highest values of the modulus. III) The analysis of variations of the flow stress according to the temperature show some connection with ordered structures, the existence of antiphase domains and the existence of sur-structure dislocations. IV) In the ordered Fe Al domain the kinetics of the Portevin-le-Chatelier effect could be explained by a mechanism of diffusion of vacancies. The role they play has been specified by the influence they exert upon the dislocations; this has led us to the inhomogeneous Rudman order; this inhomogeneous order could explain the shape of the traction curves. (author)

  18. Comparison of modification with strontium and the refining with antimony in A 356 aluminium alloys

    International Nuclear Information System (INIS)

    Strontium and Antimony treated A356 aluminium alloy samples were metallographically characterized in the as cast and solution and aged conditions. Antimony treated alloy has shown slower spheroidizing kinetics of the Silicon particles during solution treatment, lower porosity level and higher tensile strength and elongation than Strontium treated one. (author)

  19. Effect of Alloying Elements to Aluminium on the Wettability of AL/SiC System

    OpenAIRE

    Candan, Ercan

    2002-01-01

    The wettability at a liquid Al-alloy/SiC interface was evaluated by the sessile drop method at 750oC. The wetting angle, q ,of a sessile drop on SiC substrate decreased with the addition of Pb, Mg and Ca to pure aluminium. The reduction in q of the Al-Pb alloy was proportional to the reduction in surface tension, glv, of aluminium, whereas in Al-Mg and Al-Ca alloys the reduction in q was greater than the reduction in g lv of Al. This was attributed to reactions that took place at the Al-all...

  20. High temperature deformation of friction stir processed 7075 aluminium alloy

    International Nuclear Information System (INIS)

    The mechanical and microstructural properties of 7075 aluminium alloy resulting from Friction Stir Processing (FSP), into sheets of 7 mm thickness, were analysed in the present study. The sheets were processed perpendicularly to the rolling direction; the tensile mechanical properties were evaluated at room temperature in the transverse and longitudinal directions with respect to the processing one. Tensile tests were also performed at higher temperatures and different strain rates in the nugget zone, in order to analyse the superplastic properties of the recrystallized material and to observe the differences from the parent material as a function of the strong grain refinement due to the Friction Stir Process. The high temperature behaviour of the material was studied, in the parallel direction, by means of tensile tests in the temperature and strain rate ranges of 150-500 deg. C and 10- 2-10- 4 s- 1 respectively, electron microscopy (FEGSEM) observations were carried out to investigate more closely the fracture surfaces of the specimens tested at different temperatures and strain rates

  1. Galvanic corrosion of laser weldments of AA6061 aluminium alloy

    International Nuclear Information System (INIS)

    Galvanic corrosion of laser welded AA6061 aluminium alloy, arising from the varying rest potentials of the various weldment regions, was examined. The weld fusion zone is found to be the most cathodic region of the weldment while the base material is the most anodic region. The rate of galvanic corrosion, controlled by the cathodic process at the weld fusion zone, increases with time until a steady state maximum is reached. On galvanic corrosion the corrosion potential of the weld fusion zone shifts in the positive direction and the free corrosion current increases. It is proposed that the cathodic process at the weld fusion zone causes a local increase in pH that in turn causes dissolution of the surface film resulting in the loss of Al to solution and the increase of intermetallic phases. The increase in galvanic corrosion may result from either the build up of the intermetallic phases in the surface layer and/or significant increase in surface area of the weld fusion zone due to the porous nature of the surface layer

  2. Embedding of SBR feed sewage sludge in aluminium alloys

    International Nuclear Information System (INIS)

    The aim of the work was to develop a process for embedding SBR feed sewage sludge in a matrix of aluminium and Al alloys. The composition of the feed sewage sludge to be expected was researched and a suitable simulate was derived from it. The tuning behaviour of the feed sewage sludge and, building on this, the heat developed and the dose of the compounds loaded with feed sewage sludge during the intended storage time were calculated. Three processes for producing the corresponding storage compound were tested with a hydraulic press. The experiments were done with FKS simulates. For to processes, pressing into boxes and the socalled 'total synthesis', in which all components of the compound are present in powder form, compounds were produced, which comply with the given quality requirements. For a remotely operated plant in a 'hot cell', to achieve a high entry rate, total synthesis is recommended while if the technical effort is to be minimised, pressing into boxes is recommended. (orig.)

  3. Examples of liquid metal embrittlement in industrial aluminium alloys; Exemples de fragilisation par les metaux liquides dans des alliages d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Brechet, Y.; Veron, M.; Peron, S.; Deschamps, A. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie de Grenoble - ENSEEG, Lab. de Thermodynamique et Physico-Chimie Metallurgiques - LTPCM, INP Grenoble, 38 - Saint Martin d' Heres (France); Rodine, A. [MISA, Dept. of Physical Chemistry, Moscow (Russian Federation)

    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. (authors)

  4. Evaluation of mechanical properties of aluminium alloy–alumina–boron carbide metal matrix composites

    International Nuclear Information System (INIS)

    Highlights: • Fabrication of MMC with aluminium alloy–alumina–boron carbide is done. • Different proportions of reinforcements are added. • The effects of varying proportions are studied. • Investigation on mechanical properties above composites is performed. • Failure morphology analysis is done using SEM. - Abstract: This paper deals with the fabrication and mechanical investigation of aluminium alloy, alumina (Al2O3) and boron carbide metal matrix composites. Aluminium is the matrix metal having properties like light weight, high strength and ease of machinability. Alumina which has better wear resistance, high strength, hardness and boron carbide which has excellent hardness and fracture toughness are added as reinforcements. Here, the fabrication is done by stir casting which involves mixing the required quantities of additives into stirred molten aluminium. After solidification, the samples are prepared and tested to find the various mechanical properties like tensile, flexural, impact and hardness. The internal structure of the composite is observed using Scanning Electron Microscope (SEM)

  5. Localised corrosion on 2219 aluminium alloy coated with a titanium based conversion coating

    OpenAIRE

    Grilli, R.; Watts, Jf; Baker, Ma; Dunn, B.

    2010-01-01

    High strength aluminium alloys are widely employed in aerospace applications. However, specific environmental conditions may trigger corrosion and therefore these alloys require additional protection. Most current conversion coatings used for this purpose are Cr(VI) based, and thus environmentally undesirable. A possible replacement is a Ti-based coating, Nabutan STI/310. The aim of this work is to gain a better understanding of corrosion mechanisms of the Al alloy surfaces coated with Nabuta...

  6. STUDIES ON CASTING FLUIDITY AND POROSITY ON SOLIDIFICATION OF ALUMINIUM SILICON EUTECTIC ALLOY

    OpenAIRE

    Anju Ramesh; N. Saleem; N. M Najarajan

    2014-01-01

    Aluminium Silicon eutectic alloy called LM-6 contains 10 to 13% of Silicon by weight. It has good casting properties such as high strength to weight ratio and excellent corrosion resistance. So this alloy finds application in automobile, aircraft and marine industries. In this project work, modifier is added to improve the mechanical properties of LM-6 alloy such as tensile strength, fluidity and also the variation in porosity distribution. Modification is a chemical treat...

  7. Researches focused on structure of aluminium alloys processed by rapid solidification, used in automotive industry

    International Nuclear Information System (INIS)

    The paper present some new results focused on an aluminium high temperature alloy, obtained by 'melt spinning method'. alloy composition, processing conditions, resulted structures and the influence between them are presented. There are studied the two zone structures of the alloy and the relation between processing conditions and the characteristics of the zones, with implications on mechanical behavior in real conditions. The final conclusion show that is possible to control the structure in order to improve material behavior. (author)

  8. Effect of Slow Cooling in Reducing Pore Size in a Sintered Powder Metallurgical 6061Aluminium Alloy

    OpenAIRE

    S. Solay Anand; B. Mohan; T. R. Parthasarathy

    2011-01-01

    The usage of powder metallurgy aluminium compacts in lieu of ferrous components in automotives helps to lower vehicle weight. The major drawback in the commercially available press sintered aluminium alloy is porosity which is mainly dependent on the powder metallurgical process parameters such as compaction pressure, sintering temperature and cooling rate after sintering. In this paper the effect of particle size and furnace controlled cooling after sintering on porosity level and micro hard...

  9. Characterization of steam generated anti-corrosive oxide films on Aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl

    2014-01-01

    Aluminium and its alloys are widely used in structural and transportation industry owing to their high strength to weight ratio. The surface of aluminium under normal conditions has a thin oxide film (2.5-10 nm) responsible for its inherent corrosion resistance. This oxide film can further be converted or transformed into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium is strictly regulated due to its toxic nature and suspected carcinogenicity. So, it is highly imperative to develop other alternatives for chrome conversion coatings. Treatment of aluminium with natural water at elevated temperatures results in the formation of different forms of aluminium oxide (?-AlO(OH) , Al(OH)3) depending on the preparation parameters/conditions. Moreover, with the knowledge offactors controlling film growth, composition and morphology, such oxide layers carry huge potential for practical applications. Pure aluminium (AA1090, 99.94 wt. %) and other aluminium alloy surfaces were exposed to high pressure steam produced by an autoclave at a temperature of 107 – 121 °C and pressure of 15 -17 psi for 10 minutes to produce a thin coating of aluminium oxide. The aim of this study is to understand the effect of high pressure steam with and without different chemical additives on surface morphology and growth of oxide film on different intermetallic particles and corrosion behaviour of such alloys.Surface morphology was observed by using FEG-SEM, EDX and FIB-SEM. Metal oxide surface characterization and compositional depth profiling were investigated by using XRD, XPS and GD-OES respectively. Potentiodynamic polarization measurements and acid salt spray testing were used to study corrosion behavior of the produced coatings.

  10. Influence of friction stir welding parameters on properties of 2024 T3 aluminium alloy joints

    OpenAIRE

    Eramah Abdsalam M.; Rakin Marko P.; Velji? Darko M.; Tadi? Sr?an; Radovi? Nenad A.; Zrili? Milorad; Perovi? Milenko M.

    2014-01-01

    The aim of this work is to analyse the process of friction stir welding (FSW) of 3mm thick aluminium plates made of high strength aluminium alloy - 2024 T3, as well as to assess the mechanical properties of the produced joints. FSW is a modern procedure which enables joining of similar and dissimilar materials in the solid state, by the combined action of heat and mechanical work. This paper presents an analysis of the experimental results obtained by testi...

  11. Modelling research of hydrogen desorption from liquid aluminium and its alloys

    OpenAIRE

    M. Saternus

    2011-01-01

    The refining process is essential for the removing undesirable hydrogen and harmful impurities from liquid aluminium and its alloys. Physical modelling allows to observe the level of refining gas dispersion in the liquid aluminium. Test stand for physical modelling of the barbotage process of aluminum for the bath reactor (URO-200) and continuous reactor (URC-7000) were built. Measurements of the oxygen removal from water were carried out as analogy of the hydrogen desorption process from liq...

  12. The role of magnesium in the electrochemical behaviour of 5XXX aluminium-magnesium alloys:

    OpenAIRE

    Flores Ramirez, J. R.

    2006-01-01

    An investigation concerning the effects of magnesium on the intergranular corrosion susceptibility of AA5XXX aluminium alloys was carried out. In the present work, magnesium is found to be highly mobile in the bulk metal as well as in the aluminium oxide. This mobility is also found to be dependent on the temperature and bulk magnesium concentration. Interestingly, the corrosion susceptibility of the AA5XXX series appears to be directly related to the magnesium mobility as well. It was found ...

  13. Investigation of the properties of aluminium alloys used in the construction of nuclear research reactors

    International Nuclear Information System (INIS)

    In the paper there are described the results of the studies of the properties of aluminium alloys using in the construction of research reactors, especially of the Polish alloy PAR-1 which belongs to the group of Al-Mg-Si alloys. The influence of the heat treatment on structure of the alloy as well as on the mechanical and corrosion properties was studying. In the paper the results of some properties of PAR-1 alloy after irradiation were done. (author). 27 refs, 43 figs, 9 tabs

  14. Recycling of Glass Fibre Reinforced Aluminium Laminates and Silicon Removal from Aerospace Al Alloy:

    OpenAIRE

    Zhu, G.

    2012-01-01

    Aerospace aluminium alloys (7xxx and 2xxx series Al alloy) is one of the important Al alloys in our life. The recycling of aerospace Al alloy plays a significant role in sustainable development of Al industry. The fibre reinforced metal laminates GLARE including 67 wt.% 2024 Al alloy was used as upper fuselage in Airbus A380, but the solution for GLARE recycling is not available. Thermal recycling which uses high temperature to decompose the resin and separate the reinforcement fibres and fi...

  15. HIGH PURITY ALUMINIUM-LITHIUM MASTER ALLOY BY MOLTEN SALT ELECTROLYSIS

    OpenAIRE

    Watanabe, Y.; Toyoshima, M.; Itoh, K.

    1987-01-01

    The aim of this work is to develop the economical production process of the Al-Li master alloy free from metallic sodium, calcium and potassium. This master alloy can be used for aluminium-lithium alloys for structual materials of aircrafts, automobiles and robots. Moreover the Al-Li master alloy with lithium content of 18-20wt. % is applicable to the blanket of fusion reactors and the active mass of batteries. This Al-Li master alloy can be produced by means of LiCl-KCl molten salt electroly...

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

    International Nuclear Information System (INIS)

    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.

  17. Modelling of Local Necking and Fracture in Aluminium Alloys

    International Nuclear Information System (INIS)

    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 appurpose 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

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

    Directory of Open Access Journals (Sweden)

    Oladele Isiaka Oluwole

    2010-06-01

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

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

    Scientific Electronic Library Online (English)

    Oladele Isiaka, Oluwole; Omotoyinbo Joseph, Ajibade.

    2010-06-01

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

  20. Possibilities for electrochemical refining of uranium alloys with aluminium in chloride melts

    International Nuclear Information System (INIS)

    High performance of uranium separation from plutonium and closely related in electrochemical behavior basic fission products at liquid aluminium electrode is demonstrated by thermodynamic calculations experimentally, and composition of salt electrolyte for uranium-plutonium alloys electrofining is selected. Distribution of uranium and plutonium between salt (KCl-NaCl-UCl3-PuCl3) and metal (Al) phases is studied at 690 Deg C. Electrolyte composition and electrolysis conditions, when uranium and aluminium dissolve at anode and transform to cathode product at the same ratio as they are in the anode alloy, are selected

  1. Treatment of titanium alloy by pulsed heterogeneous plasma with surface burning off and alloying by aluminium and nickel

    International Nuclear Information System (INIS)

    Methods of metallography, scanning electron microscopy and X-ray analysis were used to study the effect of technological parameters on thickness, alloying degree, phase composition, structure and properties of titanium alloy surface modified by aluminium and nickel impulse alloying with surface partial melting by heterogeneity plasma of capacitor discharge. Regimes of plasmacondensate coatings formation and surface modification are determined. Fine-grained alloyed layers of a few tens microns depth have homogeneous by depth multiphase composition dependent on treatment regime. Intermetallic hardening leads to increase of hardness and wear resistance of surface layers

  2. Analysis of intermetallic particles in AlSi1MgMn aluminium alloy

    Directory of Open Access Journals (Sweden)

    G. Mrówka-Nowotnik

    2007-01-01

    Full Text Available Purpose: The main objective of this study was to analyze the morphology and composition of complexmicrostructure of the intermetallic phases in AlSi1Mg alloy.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy(LM, transmission (TEM and scanning (SEM electron microscopy in combination with X-ray analysis (EDSusing polished sample, and X-ray diffraction (XRD to identify intermetallics in AlSi1MgMn aluminium alloy.Findings: The results show that the as-cast microstructure of AlSi1MgMn alloy after slow solidification ata cooling rate 2?C/min, consisted a wide range of intermetallics phases. By using various instruments (LM,SEM, XRD and techniques (imagine, EDS the: ?-Al5FeSi, ?-Al15(FeMn3Si, Al9Mn3Si, ?-Al12Fe3Si, Mg2Siintermetallic phases were identified.Research limitations/implications: In order to complete and confirm obtained results it is recommended toperform further analysis of the 6000 series aluminium alloys. Therefore it is planned to include in a next study,microstructure analysis of the alloy by using transmission electron microscopy technique (TEM.Practical implications: Since the morphology, crystallography and chemical composition affect the intermetallicproperties, what involves changes of alloy properties, from a practical point of view it is important to understandtheir formation conditions in order to control final constituents of the alloy microstructure. This paper hasprovided essential data about various intermetallic phases precipitating in 6000 series aluminium alloys.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phasesoccurring in the 6xxx series aluminium alloys, provide wide description of the intermetallics formation throughall possible reactions and data about their chemical composition, morphology and crystallography.

  3. Finite element simulation of deep drawing of aluminium alloy sheets at elevated temperatures

    Directory of Open Access Journals (Sweden)

    G. Venkateswarlu

    2010-07-01

    Full Text Available More and more automobile companies are going for weight reduction of their vehicles for fuel economy and other features. They have started using more tailored blanked bodies using advanced joining techniques. Such material combinations usually called as “Tailor Welded Blanks” offer better characteristics. However, owing to the presence of different materials their formability is a challenge. The objective of the present study is to determine the effect of blank temperature on forming behavior of sheets and damage factor of such aluminium sheet alloys of 6061 and 7075 at elevated temperatures. An insight into such a study will throw light on the different temperatures required by the above materials when they are made into TWBs. In this present investigation, a series of simulations were carried out on the formability behaviour of cylindrical deep drawing of aluminium alloys in the temperature range 50-500 0 C using DEFORM-2D. The damage factor based on Cockcroft Latham algorithm was taken as the constraint for defect free product. The results show that forming at elevated temperature can yield significant increase in product height, especially for aluminium 7075. The deep drawing of aluminium 6061 alloys show very good formability in a temperature range between 150-2500c and 400-5000c for aluminium 7075. Both the metals gave identical cup heights when drawn at 4750c.

  4. Recent developments of the aluminium-lithium system alloys for aircraft uses

    International Nuclear Information System (INIS)

    A brief review is made of the latest developments in the production of Aluminium-Lithium alloys. The necessity for new materials in the field of aeronautics has speeded up research on metallic and non-metallic materials. Lately, a good part of the research in the field of metallic components has been directed at Al-Li alloys. More recently, with the development of quaternary alloys Al-Li-X-X, the old problem of low toughness was overcome. The finality of this study is to cover the developments of the mentioned alloys, including the fundamentals of physical metallurgy of the complex system recently developed Al-Li-Cu-Mg. (author)

  5. Galvanic corrosion of rare earth modified AM50 and AZ91D magnesium alloys coupled to steel and aluminium alloys

    International Nuclear Information System (INIS)

    Electrochemical and gravimetric measurements were used to examine the effects of neodymium and gadolinium additions on the galvanic corrosion behaviour of AM50 and AZ91D magnesium alloys coupled to A 570 Gr 36 carbon steel and AA2011-AA6082 aluminium alloys. Rare earth modified alloys showed Al2Nd/Al2Gd and Al-Mn-Nd/Al-Mn-Gd intermetallics, reduced area fraction of ?-Mg17Al12 phase and increased corrosion resistance due to increased surface passivity and suppression of micro-galvanic couples. Neodymium and gadolinium additions improved the galvanic corrosion resistance of AM50 alloy, but were less effective in case of the AZ91D alloy. The AA6082 alloy was the most compatible material and the AA2011 alloy was the least compatible. (Author)

  6. Galvanic corrosion of rare earth modified AM50 and AZ91D magnesium alloys coupled to steel and aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, M.; Arrabal, R.; Pardo, A.; Paucar, A.; Merino, M. C.; Matykina, E.; Mingo, B.; Garces, G.

    2014-04-01

    Electrochemical and gravimetric measurements were used to examine the effects of neodymium and gadolinium additions on the galvanic corrosion behaviour of AM50 and AZ91D magnesium alloys coupled to A 570 Gr 36 carbon steel and AA2011-AA6082 aluminium alloys. Rare earth modified alloys showed Al{sub 2}Nd/Al{sub 2}Gd and Al-Mn-Nd/Al-Mn-Gd intermetallics, reduced area fraction of {beta}-Mg{sub 1}7Al{sub 1}2 phase and increased corrosion resistance due to increased surface passivity and suppression of micro-galvanic couples. Neodymium and gadolinium additions improved the galvanic corrosion resistance of AM50 alloy, but were less effective in case of the AZ91D alloy. The AA6082 alloy was the most compatible material and the AA2011 alloy was the least compatible. (Author)

  7. Evaluation of the mechanical properties of microarc oxidation coatings and 2024 aluminium alloy substrate

    CERN Document Server

    Xue Wen Bin; Deng Zhi Wei; Chen Ru Yi; Li Yong Liang; Zhang Ton Ghe

    2002-01-01

    A determination of the phase constituents of ceramic coatings produced on Al-Cu-Mg alloy by microarc discharge in alkaline solution was performed using x-ray diffraction. The profiles of the hardness, H, and elastic modulus, E, across the ceramic coating were determined by means of nanoindentation. In addition, a study of the influence of microarc oxidation coatings on the tensile properties of the aluminium alloy was also carried out. The results show that the H-and E-profiles are similar, and both of them exhibit a maximum value at the same depth of coating. The distribution of the alpha-Al sub 2 O sub 3 phase content determines the H- and E-profiles of the coatings. The tensile properties of 2024 aluminium alloy show less change after the alloy has undergone microarc discharge surface treatment.

  8. Recovery of actinides from actinide–aluminium alloys by chlorination: Part II

    International Nuclear Information System (INIS)

    A chlorination route is being investigated for recovery of actinides from actinide–aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl–KCl. In the present work, the most important steps of this route were experimentally tested using U–Pu–Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the salt adhered on the electrode, chlorination of the alloy by chlorine gas and sublimation of the AlCl3 formed. The processes parameters were set on the base of a previous thermochemical study and an experimental work using pure UAl3 alloy. The present experimental results indicated high efficiency of salt distillation and chlorination steps, while the sublimation step should be further optimised

  9. Recovery of actinides from actinide–aluminium alloys by chlorination: Part II

    Energy Technology Data Exchange (ETDEWEB)

    Sou?ek, P., E-mail: pavel.soucek@ec.europa.eu [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Génie Chimique (LGC), Département Procédés Electrochimiques, CNRS-UMR 5503, Université de Toulouse III – Paul Sabatier, 31062 Toulouse Cedex 9 (France); Eloirdi, R.; Malmbeck, R.; Meier, R.; Nourry, C.; Claux, B.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2014-04-01

    A chlorination route is being investigated for recovery of actinides from actinide–aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl–KCl. In the present work, the most important steps of this route were experimentally tested using U–Pu–Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the salt adhered on the electrode, chlorination of the alloy by chlorine gas and sublimation of the AlCl{sub 3} formed. The processes parameters were set on the base of a previous thermochemical study and an experimental work using pure UAl{sub 3} alloy. The present experimental results indicated high efficiency of salt distillation and chlorination steps, while the sublimation step should be further optimised.

  10. Effect of alloying components on passivation of alloys based on titanium and aluminium in molten alkali carbonates

    International Nuclear Information System (INIS)

    The corrosion-electrochemical behaviour of alloys on the basis of titanium and aluminium in the eutectic mixture of lithium, sodium and potassium carbonates at the temperature of 773-973 K is studied. Roentgenographic analysis of products of interaction of metals with a melt is carried out and their corrosion is calculated

  11. Development of Al-TiC Alloys Using Powder Metallurgy as Grain Refiners for Aluminium and Its Alloys

    Directory of Open Access Journals (Sweden)

    Abdel-Nasser .M. Omran

    2014-07-01

    Full Text Available Al-Ti-C master alloys have been widely investigated for many years as grain refiner for aluminium and its alloys. In this work, the Al-Ti-C master alloys are synthesized using powder metallurgy technique through the mixing of aluminium and TiC powders with different TiC contents 3.75 (3, 5(4, 6.25(5 and 7.5(6 Wt% TiC(Wt% Ti. The mixing powders with different contents of TiC were pressed in cylinder shape. The pressed specimens were sintered from 450 oC in a tube furnace under argon atmosphere for 2 hrs. The produced alloys before and after sintering are examined using SEM, EDX and XRD. The results indicate that, the Al-TiC alloy containing fine TiC particles dispersed in all matrix was successfully prepared. The prepared Al-TiC alloys with different contents of TiC were evaluated using the KBI test mold as grain refiner for pure aluminum and its alloys. The results indicate that the prepared Al-TiC master alloy is high grain refining efficiency for pure aluminum and its alloys.

  12. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Cecchetto, L. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France); Ambat, R. [School of Engineering Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Davenport, A.J. [School of Engineering Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Delabouglise, D. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France)]. E-mail: Didier.Delabouglise@lepmi.inpg.fr; Petit, J.-P. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France); Neel, O. [Centre de Recherche de Voreppe, Pechiney, Parc economique Centr' Alp, 38340 Voreppe (France)

    2007-02-15

    AA5182 aluminium alloy cold rolled samples were coated by thin films of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very effective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains factors:- a weak redox activity of the polymer which passivate the metal, - a proton involving self-healing process taking place at the polymer-metal interface, which contributes to delay local acidification in first steps of corrosion on EB coated aluminium surfaces.

  13. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan

    2007-01-01

    AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains factors: • a weak redox activity of the polymer which passivate the metal, • a proton involving self-healing process taking place at the polymer–metal interface, which contributes to delay local acidiWcation in Wrst steps of corrosion on EB coated aluminium surfaces.

  14. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    International Nuclear Information System (INIS)

    AA5182 aluminium alloy cold rolled samples were coated by thin films of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very effective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains factors:- a weak redox activity of the polymer which passivate the metal, - a proton involving self-healing process taking place at the polymer-metal interface, which contributes to delay local acidification in first steps of corrosion on EB coated aluminium surfaces

  15. High Pressure Die Casting of Aluminium and Magnesium Alloys :Grain Structure and Segregation Characteristics

    OpenAIRE

    Laukli, Hans Ivar

    2004-01-01

    Cold chamber high pressure die casting, (HPDC), is an important commercial process for the production of complex near net shape aluminium and magnesium alloy castings. The work presented in the thesis was aimed at investigating the microstructure formation in this type of casting. The solidification characteristics related to the process and the alloys control the formation of grains and defects. This again has a significant impact on the mechanical properties of the castings. The investigati...

  16. Possibility of the elimination of intermetallic inclusions in heat affected zone during aluminium alloy welding

    International Nuclear Information System (INIS)

    A study was made on possibility of reduction of heat affected zone structure (the region of overaging) of 1201 aluminium heat-treatable alloy by transfer of atoms of alloying admixtures from intermetallic inclusions into solid solution and the folloWing artificial ageing. It was shown that 14 MeV electron irradiation at -186 deg C produces solvent effect on stable phase precipitations. Possibility of application of such process to welding technology was evaluated

  17. MICROSTRUCTURAL CHARACTERISATION AND CORROSION BEHAVIOUR OF TOP SURFACE OF TIG WELDED 2219?T87 ALUMINIUM ALLOY

    OpenAIRE

    Venkatasubramanian, G.; A. Sheik Mideen; Abhay K. Jha

    2013-01-01

    The microstructural characterisation and corrosion behaviour of top surface of tungsten inert gas (TIG) welded 2219?T87 aluminium alloy (AA2219–T87) in 0.6 M NaCl solution was studied by optical microscopy, scanning electron microscopy (SEM), potentiodynamic polarisation, and electrochemical impedance spectroscopy (EIS). The optical microscopy and SEM analyses revealed that the welding of base metal (BM) with ER2319 filler alloy caused the formation of micro pores and micro cracks on the ...

  18. Arc welding of high strength aluminium alloys for armour systems applications

    OpenAIRE

    Pickin, Craig Graeme

    2011-01-01

    The ternary Al-Cu-Mg system 2xxx series aluminium alloys were examined as construction materials for armour system applications based upon comparable ballistic properties to the currently employed Al-7xxx series alloys. Utilising MIG welding solidification cracking was evident when welding constrained Al-2024 candidate base material using Al-2319 filler, the only available consumable wire for this series. A previously developed thermodynamic model suggested that an incompatible...

  19. Use of acoustic energy in the processing of molten aluminium alloys

    OpenAIRE

    Puga, He?lder; Barbosa, J.; Costa, So?nia; Ribeiro, Carlos Silva

    2013-01-01

    During the last years aluminium alloys have been gaining increased acceptance as structural materials in the automotive and aeronautical industries, mainly due to their light weight, good formability and corrosion resistance. However, improvement of mechanical properties is a constant in research activities, either by the development of new alloys or by microstructure manipulation. This presentation focuses a novel effective dynamic methodology to perform microstructural refinement / modi...

  20. Latest investigations for determination of oxygen content in aluminium and its alloys

    International Nuclear Information System (INIS)

    Thin layer on the surface of metal prevents to determine oxygen content in the high purity aluminium and in its alloys. Experiments and their results have been presented, directed towards elimination of errors appearing due to the surface oxides during activation analysis by means of a neutron generator application

  1. Vacuum brazing of aluminium metal matrix composite (55 vol.% SiCp/A356) using aluminium-based filler alloy

    International Nuclear Information System (INIS)

    Highlights: ? The proper filler metal has been developed, especially for contents of Mg and Si. ? The pressure device has been designed for specimen in vacuum brazing process. ? The accurate measurement method for shear strength of lap joint has been found. ? The brazing temperature of 560 °C has been optimised. ? The micro-mechanism has been discussed for SiCp/Al composites’ brazing joint. - Abstract: Aluminium matrix composites with high volume fractions of SiC particles, as the reinforcements, are potentially suitable materials for electronic packaging. These composites, due to their poor weldability, however, have very limited applications. The microstructure and shear strengths of the bonds made in 55 vol.% SiCp/A356 composite, using an aluminium based filler alloy containing Cu, Si, Mg and Ni, were investigated in this paper. The brazing temperature had a clear effect on the bond integrity, and the samples brazed at 560 °C demonstrated good bonding between the filler alloy and the SiC particles. The maximum shear strength achieved in this work was 102 MPa.

  2. Effect of mechanical alloying and Ti addition on solution and ageing treatment of an AA7050 aluminium alloy

    Scientific Electronic Library Online (English)

    Kátia Regina, Cardoso; Dilermando Nagle, Travessa; Asunción García, Escorial; Marcela, Lieblich.

    2007-06-01

    Full Text Available In this work, solution heat treatments at different temperatures were performed in a commercial based AA7050 aluminium alloy, with and without titanium addition, produced by mechanical alloying and hot extrusion with the aim to investigate the effect of titanium addition and mechanical alloying in t [...] he precipitates stability. The same heat treatment conditions were used in a reference sample obtained from a commercial AA7050 alloy. Solution heat treated samples were characterised by differential scanning calorimetry (DSC), optical microscopy and hardness test. Once the better temperature for the solution treatment of modified alloys was defined, the ageing curve at 120 °C was obtained to verify the effect of milling and Ti addition in the precipitation and in the maximum values of hardness obtained for the alloys.

  3. Structure and selected properties of high-aluminium Zn alloy with silicon addition

    Directory of Open Access Journals (Sweden)

    A. Zyska

    2011-07-01

    Full Text Available The results of examinations concerning the abrasive wear resistance, hardness, and thermal expansion of high-aluminium zinc alloys are presented. The examinations were carried out for five synthetic ZnAl28 alloys with variable silicon content ranging from 0.5% to 3.5%, and – for the purpose of comparison – for the standardised ZnAl28Cu4 alloy. It was found that silicon efficiently increases the tribological properties and decreases the coefficient of thermal expansion of zinc alloys. The most advantageous set of the examined properties is exhibited by the alloys containing over 2.5% Si. They are characterised by higher parameters as compared with the standardised alloy. Observations of microstructures reveal that silicon precipitates as a separate compact phase, and its morphology depends on t he Si content in the alloy. The performed examinations show that silicon can satisfactorily replace copper in high aluminium Zn alloys, thus eliminating the problem of dimensional instability of castings.

  4. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    International Nuclear Information System (INIS)

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl3. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl2/UAl3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl5 and UCl6. The results showed high efficient chlorination at a temperature of 150 deg. C.

  5. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Energy Technology Data Exchange (ETDEWEB)

    Cassayre, L., E-mail: cassayre@chimie.ups-tlse.fr [Laboratoire de Genie Chimique (LGC), Departement Procedes Electrochimiques, CNRS-UMR 5503, Universite de Toulouse III - Paul Sabatier, 31062 Toulouse (France); Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    2011-07-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl{sub 3}. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl{sub 3} alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl{sub 2}/UAl{sub 3} molar ratio, providing complete chlorination of the alloy without formation of volatile UCl{sub 5} and UCl{sub 6}. The results showed high efficient chlorination at a temperature of 150 deg. C.

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

    Science.gov (United States)

    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. PMID:14761750

  7. Development of multilayer coatings for forming dies and tools of aluminium alloy from liquid state

    International Nuclear Information System (INIS)

    In this work, a nanocomposite (Cr,Al)xN1-x/Si3N4 coating system was deposited on H11 hot work tool steel, using the Lateral Arc Rotating Cathodes (LARC (registered) ) deposition system and modulating the chemical composition of the chromium and aluminium-silicon content. Structural characterizations were performed using scanning electron microscopy, equipped with energy dispersive spectroscopy probe, and applying x-ray diffraction, for the evaluation of phase constitution and crystallite size. In addition to the structural features, the coatings' resistance to cyclic immersions in molten aluminium alloy was evaluated. The deposited CrAlSiN coatings exhibited an fcc-Cr1-xAlxN type structure with different aluminium contents, which directly influence hardness and wear and fatigue resistance in cyclic immersion tests. The main failure modes that occurred on the coatings' surface were soldering and thermal fatigue cracks mainly in the form of heat checks. The aluminium rich coatings were able to withstand about 15 000 cycles, whereas the decrease in the aluminium content in the coatings results in a decrease in the resistance to the immersion in molten aluminium bath. It is worthwhile to note that uncoated H11, subjected to similar testing conditions, withstood at maximum 5000 cycles.

  8. STUDIES ON CASTING FLUIDITY AND POROSITY ON SOLIDIFICATION OF ALUMINIUM SILICON EUTECTIC ALLOY

    Directory of Open Access Journals (Sweden)

    Anju Ramesh

    2014-08-01

    Full Text Available Aluminium Silicon eutectic alloy called LM-6 contains 10 to 13% of Silicon by weight. It has good casting properties such as high strength to weight ratio and excellent corrosion resistance. So this alloy finds application in automobile, aircraft and marine industries. In this project work, modifier is added to improve the mechanical properties of LM-6 alloy such as tensile strength, fluidity and also the variation in porosity distribution. Modification is a chemical treatment of metal in molten condition which is done along with fluxing, grain refining and degassing. Therefore LM-6 alloy can be strengthened by modification. These properties of LM-6 alloy with modification and without modification are also compared in this project. Test results reveal that modification enhances strength of LM-6 alloy considerably and also it reduces porosity. A small amount of reduction is noted in fluidity,while increasing the addition of modifier.

  9. Appearance of anodised aluminium: Effect of alloy composition and prior surface finish

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Canulescu, Stela

    2014-01-01

    Effect of alloy composition and prior surface finish on the optical appearance of the anodised layer on aluminium alloys was investigated. Four commercial alloys namely AA1050, Peraluman 706, AA5754, and AA6082 were used for the investigation. Microstructure and surface morphology of the substrate prior to anodising were analysed using scanning electron microscopy and atomic force microscopy. The optical appearance of the anodised surface with and without sealing was investigated using a photography setup, photospectrometry and bidirectional reflectance distribution function. It was found that the roughness of the as-etched surface increases with the degree of alloying due to second phase particles making the reflection more diffused, and that the as-etched surface morphology is similar to the oxide–substrate interface after anodising. Proper polishing is achieved on hard alloys and the glossy appearance was kept for alloys of high purity. Sealing made the specular reflection of the mechanically polished specimens more distinct.

  10. An approach for continuous cooling transformation (CCT) diagrams of aluminium alloys

    International Nuclear Information System (INIS)

    Two different kinds of time temperature transformation (TTT) diagrams are known. The first one are isothermal transformation (IT) diagrams and the second one continuous cooling transformation (CCT) diagrams. These diagrams are important for the correct heat treatment of aluminium alloys, because they provide information about the required quenching rate, which is necessary to obtain a supersaturated solid solution during age hardening. Furthermore, it is possible to determine the lowest quenching rate, which permits both a high strength and a small distortion of the component after age hardening. In the literature IT diagrams for different aluminium alloys are available. To determine these diagrams, a solution annealing followed by quenching to defined temperatures is necessary. At these temperatures the alloy is kept isothermally until a transformation has started. These diagrams are not directly portable on continuous cooling, because of the different cooling paths. (orig.)

  11. The influence of alloying elements in aluminium on the grain refinement with ALTI5B1

    Directory of Open Access Journals (Sweden)

    Nagli? I.

    2009-07-01

    Full Text Available This work deals with the influence of alloying elements in aluminium on the grain refinement with various additions of AlTi5B1. Grain-refinement tests were made at a cooling rate of 15 °C/s. The results revealed that in both aluminium and an Al-Fe alloy the grain size decreases with increasing additions of the AlTi5B1 grain refiner. We found that for the same boron content the grain size was smaller in the case of the Al-Fe alloy. The difference in the grain sizes for the same content of boron was approximately 15 ?m; this is considerably smaller than the difference between the grain sizes in samples with the same difference of growth-restricting factor made at slower cooling rates.

  12. Microstructural and electrochemical characterization of environmentally friendly conversion layers on aluminium alloys

    OpenAIRE

    Palomino Luis Enrique M.; Castro João Fábio W. de; Aoki Idalina V.; Melo Hercílio G. de

    2003-01-01

    Cerium conversion layers (CeCL) have been investigated as a replacement for chromium conversion layers to protect Al alloys against corrosion. In this work the microstructure and the electrochemical behaviour of aluminium alloy 2024 with and without CeCL were investigated using, respectively, SEM-EDX and EIS. EDX results have shown that the presence of dispersed plated Cu particles on the alloy surface enhances the formation of the CeCL increasing the intensity of Ce peaks in the EDX spectra....

  13. Influence of corrosion and creep on intergranular fatigue crack path in 2XXX aluminium alloys

    OpenAIRE

    Hénaff, Gilbert; Menan, Frédéric; Odemer, Grégory

    2010-01-01

    In this paper, two examples of the influence of time-dependent processes on crack path in two 2XXX aluminium alloys are presented. The first example is concerned with corrosion–fatigue crack growth resistance of a 2024 T351 alloy cracked in the S–L direction in 3.5% NaCl solution at free corrosion potential. The second example deals with the elevated temperature crack growth resistance of a 2650 T6 alloy that might be used in future supersonic aircraft fuselage panels. The common idea is to c...

  14. Investigation into the strength of components made of UFG aluminium alloys

    OpenAIRE

    Lang, H.; Bruzek, B.; Leidich, E.; Semmler, U.

    2008-01-01

    Aluminium is a very important light metal used in nearly all fields of engineering. Several high strength alloys are available, especially alloys of the EN AW-6XXX- and 7XXX-type. In spite of the fact that these alloys are suitable for heat treatment in order to reach minimum ultimate tensile strength of 310 MPa for EN AW-6082 and 560 MPa for EN AW-7075 respectively there is the need to improve several material properties like ultimate strain or corrosion resistance. A possible way to optimiz...

  15. Electrospark Coatings Based on WC-Co Alloys with Aluminium Oxide and Carbon Additives

    Directory of Open Access Journals (Sweden)

    Nikolay A. Suy

    2013-03-01

    Full Text Available The structure and properties of coatings based on WC-Co alloys containing additives of 1% - 5% aluminium oxide and 2.5% - 4.5% carbon were investigated. The coatings had a nanocrystalline structure. Depending on the duration and frequency of the discharge pulses, the ratio between WC and W2C in the coatings was different. The additives in the hard alloy allowed us increase the microhardness and wear resistance of the coatings by a factor of 2 - 3 in comparison to coatings created using a conventional WC-10%Co alloy.

  16. Abrasive wear response of aluminium alloy-sillimanite particle reinforced composite under low stress condition

    International Nuclear Information System (INIS)

    The abrasive wear behaviour of aluminium alloy-sillimanite particle reinforced composite under low stress condition has been reported and the results have been compared with the corresponding matrix alloy which was produced and cast under similar conditions. The study showed that wear resistance (inverse of wear rate) of the composite was higher than the matrix alloy. The wear rate decreased with sliding distance and increased with applied load irrespective of materials. The worn surfaces and subsurfaces of the tested samples were examined in the scanning electron microscope in order to understand the material removal mechanism during low stress abrasive wear process

  17. Characterisation of early precipitation stages in 6xxx series aluminium alloys

    Science.gov (United States)

    Hasting, Håkon S.; Walmsley, John; Marioara, Calin D.; van Helvoort, ATJ; Holmestad, Randi; Danoix, Frederic; Lefebvre, Williams

    2006-02-01

    Advanced microscopy techniques such as high angular annular dark field scanning transmission electron microscopy and energy filtered transmission electron microscopy are being explored to study early precipitation stages of 6XXX-series aluminium alloys. Observations are combined with those from 3 dimensional atom probe studies of the same materials. GP-zones are imaged by annular dark field scanning transmission electron microscopy and plasmon mapping. Developed clusters are investigated and quantified by atom probe, and a high number density of clusters with a Mg/Si-ratio close to the alloy composition are confirmed to be present in the alloy.

  18. Characterisation of early precipitation stages in 6xxx series aluminium alloys

    International Nuclear Information System (INIS)

    Advanced microscopy techniques such as high angular annular dark field scanning transmission electron microscopy and energy filtered transmission electron microscopy are being explored to study early precipitation stages of 6XXX-series aluminium alloys. Observations are combined with those from 3 dimensional atom probe studies of the same materials. GP-zones are imaged by annular dark field scanning transmission electron microscopy and plasmon mapping. Developed clusters are investigated and quantified by atom probe, and a high number density of clusters with a Mg/Si-ratio close to the alloy composition are confirmed to be present in the alloy

  19. Gating System Design for Casting thin Aluminium Alloy (Al-Si) Plates

    OpenAIRE

    Victor ANJO; Reyaz KHAN

    2013-01-01

    The main problems caused by improper gating are entrained aluminium oxide films, cuts and washes, low casting yield and entrapped gas. This study describes the design of a gating system to produce thin Aluminium cast alloy plates of different sizes and thicknesses of 4mm, 6mm, 8mm, and 10mm using the non-pressurized gating with ratio of 1:4:4 and green sand moulding technique. The gating design was based on the laws of fluid mechanics and empirical rules of gating for non ferrous metals. The ...

  20. Effect of composition on the superplasticity of aluminium scandium alloys

    International Nuclear Information System (INIS)

    Several aluminum alloys have been shown to exhibit superplasticty in the as-rolled condition. Previous work has shown that aluminum-scandium alloys also exhibit this behavior, but only with the addition of ternary alloying elements such as lithium and magnesium. These additions raised the strain-rate sensitivity of these alloys to 0.4-0.5 for selected strain rates at temperatures above 400 degrees C. A systematic study was undertaken of five Al-Sc alloys with varying lithium and magnesium concentrations in order to fully characterize the high temperature deformation mechanism. Specimens were deformed at a constant strain rate to predetermined true strains for textural and microstructural characterization. In this paper work is presented that will elucidate the effect of these different ternary additives on the superplastic deformation mechanism in these alloys

  1. Surface modification of aluminium alloys using hybrid treatment techniques

    Science.gov (United States)

    Petrov, P.

    2012-03-01

    The application of electron and laser beams to the modification of metal and alloys opens up new possibilities of improving the materials properties. In recent years, the studies aimed at developing new materials have brought about the development of hybrid treatment techniques. These techniques perform an additional alloying in the zone treated, which has a substantial effect on the physical and mechanical properties of the materials processed. In this work we report results on the microstructural changes and mechanical properties of heat-treated AlSi12CuNiMg alloys resulting from additional alloying with Fe, Co, Ni, Cr by hybrid electron-beam techniques. It is established that the mechanical properties of Al-Si alloys can be improved by means of additional alloying with Fe, Co, Ni, Cr by hybrid electron-beam techniques. The specimens' properties practically do not change after heat-treatment (aging) for up to 200 hours at 250 °C.

  2. Laser surface treatment of magnesium alloys with aluminium oxide powder

    OpenAIRE

    Dobrzan?ski, L. A.; Malara, S.; Tan?ski, T.

    2009-01-01

    Purpose: The aim of this paper was to improve the magnesium cast alloys surface layer by laser surface treatment and to determine the laser treatment parameters.Design/methodology/approach: The laser treatment of magnesium alloys with alloying Al2O3 powder of the particle about 80?m was carried out using a high power diode laser (HPDL). The resulting microstructure in the modified surface layer was examined using scanning electron microscopy. Phase composition was determined by the X-ray dif...

  3. Understanding the role of oxidation in bonding of aluminium alloys

    OpenAIRE

    Wu, Guo; O‘Reilly, Keyna; Galano, Marina

    2014-01-01

    The main aim of this work is to study the bonding behaviour of Al alloys as a function of temperature, time and processing conditions from a perspective of oxidation so as to gain a comprehensive knowledge of the oxidation issues during processing and to design better bonding approaches for different alloy systems. Two major parts of work have been carried out during the study: (a) the use of a stacking approach and a double pouring approach to potentially join two Al alloys a...

  4. Superlattices in iron-rich iron-aluminium alloys

    International Nuclear Information System (INIS)

    The state of order of iron-rich iron-aluminium single crystals has been determined by diffuse elastic neutron scattering experiments. The atomic fraction of Al was between 0.2 and 0.3. Up to about 1300 K, all specimens have the DO3-superlattice. The long-range order parameter is always high. The size of the antiphase domains decreases as the temperature is raised or the Al-concentration lowered. (orig.)

  5. Wear Properties of Alumina Particles Reinforced Aluminium Alloy Matrix Composite

    OpenAIRE

    Faiz Ahmad; Rafi Raza, M.; Majdi Ab Rani, A.; Jason Lo, S. H.

    2011-01-01

    In this study results of wear and friction coefficient of alumina particles reinforced Aluminium Matrix Composite (AMCs) were presented. The wear of AMCs was tested against the brake pad material under various loads ranging from 50 to 200 N at fixed speed of 600 rpm. A pin on-disk apparatus was used for measurement of wear rate of AMCs and resulting microstructure at each load was examined under scanning electron microscope. The coefficient of friction was also measured for corresponding load...

  6. Wear Performance and Hardness Property Of A356.1 Aluminium Alloy Reinforced with Zirconium Oxide Nano Particle

    OpenAIRE

    Girisha.K.B1 ,; Chittappa, Dr H. C.

    2014-01-01

    Aluminium alloy reinforced with Nano-sized ZrO2 particles are widely used for high performance applications such as automotive, military, aerospace, and electricity industries because of their improved physical and mechanical properties. In this research, Zirconium Oxide (ZrO2) Nano particles were synthesized by Solution Combustion Synthesis process. The Nano particles were characterized by Powder X-ray diffraction (PXRD) and TEM. A356.1 Aluminium alloy was reinforced with 0.5...

  7. Impact toughness improvement of high strength aluminium alloy by intrinsic and extrinsic fracture mechanisms via hot roll bonding

    OpenAIRE

    Cepeda-Jiménez, C. M.; García-Infanta, J.M.; Pozuelo, M.; Ruano, Oscar Antonio; Carreño, Fernando

    2009-01-01

    A multilayer aluminium laminate comprising ten layers of Al-Zn-Mg-Cu alloy (82 vol.%) and nine layers of pure aluminium (18 vol.%) has been processed by hot rolling. The rolled laminate was characterized by electron backscattering diffraction, Charpy impact and shear tests. The multilayer laminate showed an outstanding Charpy impact toughness, being eighteen times higher than that for the as-received Al-Zn-Mg-Cu alloy. Damage tolerance improvement was due to the high volume fra...

  8. Predicting tensile strength of friction stir welded AA6061 aluminium alloy joints by a mathematical model

    International Nuclear Information System (INIS)

    AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, 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 tool pin profile play a major role in deciding the joint strength. An attempt has been made to develop a mathematical model to predict tensile strength of the friction stir welded AA6061 aluminium alloy by incorporating FSW process parameters. Four factors, five levels central composite design has been used to minimize number of experimental conditions. Response surface method (RSM) has been used to develop the model. Statistical tools such as analysis of variance (ANOVA), student's t-test, correlation co-efficient etc. have been used to validate the developed model. The developed mathematical model can be effectively used to predict the tensile strength of FSW joints at 95% confidence level

  9. Vacancies in aluminium and dilute Al alloys - an investigation by positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Aluminium and its alloys are widely applied in our daily lives as construction material, food packages and so on due to their unique properties, namely light weight and high strength. In case of age-hardenable Al alloys used e.g. in automotive and aviation industry they are greatly influenced by precipitates which are usually formed through vacancy driven diffusion. In Al alloys quenched-in vacancies will be trapped by solute atoms, but in pure aluminium they diffuse to the surface, grain boundaries, dislocations and disappear at room temperature. In this study HCl solution cooled to 203 K is used instead of water as quenching medium in order to optimize quenching rate, and to freeze vacancies at such temperature. Based on this quenching method a vacancy reference in pure aluminium is obtained by using positron annihilation techniques, which are especially suitable for the investigation of open volume defects, since positrons are highly sensitive to vacancies. The results are then compared to dilute Al alloys. In this way information about solute concentration around vacancies and/or their relaxation can be obtained.

  10. Application of spectral analysis of the electrochemical noise to the investigation of aluminium alloy pitting corrosion

    International Nuclear Information System (INIS)

    The objective of this research is to decode (at least partially) the nature of the information contained in the electrochemical noise associated with the pitting corrosion phenomenon in aluminium alloys. After a general presentation of aluminium and its alloys and a report of a bibliographical study on the electrochemical noise, the author gives an overview of a theoretical approach of stochastic phenomena, and of an experimental approach. Then, the experimental investigation of the electrochemical noise in the case of pitting corrosion leads to a noise control law, to a study of the structure of pitting growth, and to the elaboration of a procedure of assessment of spectral characteristics of this noise. The author reports a systematic study of the electrochemical noise with respect to the parameters of the control law. Results allow a quantitative characterization of pitting corrosion resistance of the studied alloys, notably by using the kinetic aspect of pitting growth and the structure of pitting corrosion. The author discusses the physicochemical nature of random fluctuations which build up the noise. He proposes a more precise explanation of phenomena related to initiation and propagation of pitting corrosion on aluminium alloys in marine environment

  11. Microstructure and interfaces of a reaction coating on aluminium alloys by laser processing

    International Nuclear Information System (INIS)

    This paper reports an approach to coat a ceramic layer on aluminium alloys by means of chemical reaction. The reaction product of Al2O3 layer of 100 ?m in thickness has been formed using a powder mixture of silicon oxide and aluminium by laser processing. It turns out that the large amount of heat from the exothermic reaction has a predominate effects on the formation of the oxide layer. Further, the negative free energy of the reaction may promote the metal/oxide wetting. The micro-hardness and wear tests proved that the oxide layer is hard and strong. A mullite intermediate layer between aluminium and oxide have been identified by TEM. The atomic structure and defects of the reaction layer have been imaged at high resolution electron microscope. (orig.)

  12. Modelling research of hydrogen desorption from liquid aluminium and its alloys

    Directory of Open Access Journals (Sweden)

    M. Saternus

    2011-10-01

    Full Text Available The refining process is essential for the removing undesirable hydrogen and harmful impurities from liquid aluminium and its alloys. Physical modelling allows to observe the level of refining gas dispersion in the liquid aluminium. Test stand for physical modelling of the barbotage process of aluminum for the bath reactor (URO-200 and continuous reactor (URC-7000 were built. Measurements of the oxygen removal from water were carried out as analogy of the hydrogen desorption process from liquid aluminium. In the research the distilled water saturated with the compressed oxygen was used. The level of water saturation with oxygen and then oxygen desorption from water was reached by means of the dissolved oxygen meter Elmetron CO-401.

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

    Science.gov (United States)

    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. PMID:20022189

  14. Corrosion of alloys of the niobium--titanium--aluminium system

    International Nuclear Information System (INIS)

    The mechanical properties and corrosion resistance of niobium--titanium--aluminum alloys in 20 percent HCl and 40--75 percent H2SO4 at 40 and 1000C are considered. Current density vs potential and corrosion rate vs potential potentiostatic curves plotted in 75 percent H2SO4 at 1400C for the alloys with different titanium contents at a constant content of aluminum and also for alloys with a constant titanium content at different contents of aluminum are given. It was shown that the corrosion resistance of the alloys in 75 percent H2SO4 at 1400C is an exponential function of the atomic content of the alloying components (Ti, Al) in them; aluminum vitiates the corrosion resistance very strongly

  15. Anti-corrosive Conversion Coating on Aluminium Alloys Using High Temperature Steam

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl

    Aluminium is extensively used as a structural material due to its excellent strength to weight ratio and corrosion resistance properties. The surface of aluminium under normal conditions has a thin oxide film (1-10nm) which provides corrosion resistance. However due to lower thickness, flaws and heterogeneity of native oxide layer does not provide long time corrosion resistance and adhesion of organic coating for a particular function in different environments. In order to enhance the corrosion resistance and adhesion of organic coating, the aluminium native oxide layer is treated to transform or convert to a functional conversion coating. In the last several decades chromate conversion coating (CrCCs) have been the most common conversion coatings used for aluminium alloys. Due to the toxicity of the hexavalent chrome, however, environmental friendly alternatives to CrCCs have been investigated extensively. Despite the intense research no equivalent substitute for (CrCCs) has been found. For these reasons, alternative conversion coatings are sought for substituting existing ones. Aluminium alloys AA 1090, Peraluman 706, and AA 6060 were subjected to high pressure steam treatment and various chemistries based on pH and oxidizing capabilities. Treatment is carried out in an autoclave at a temperature of 110 – 112 °C and pressure of 5 Psi for varying times. The growth and composition of the oxide layer was investigated in detail as a function of microstructure using GD-OES, FEG-SEM, EDX, FIB-SEM, XRD, and FTIR. Potentiodynamic polarization measurements and acid salt spray testing were used to study the corrosion behavior of the produced coatings. In average, thickness of the oxide layer formed was increased to ~1-1.5 µm with steam treatment and various chemistries, and the coverage on the surface was dependent on the microstructure of the alloy, particularly the composition of the intermetallics. Mechanism of the coating formation will be elucidated.

  16. Structural corrosion resisting aluminium base alloy having a good neutron shielding effect

    International Nuclear Information System (INIS)

    Purpose: To provide aluminium base alloys of good weldability, corrosion resistance, and strength well suited as a structural material for reactors and spent fuel storage. Constitution: The alloy of the present invention comprises suitable constituents selected from MgO; 0.5 - 5.5%, B; 0.4 - 3.4%, Zn; less than 2%, Mn; less than 1.5%, Fe Co Ni Cu Li; less than 1.0%, Cr Zr Ti V W Mo Cd; less than 0.5%, and the remainder, Al. For example, a spent fuel storage was constructed from alloys of Al - 4.5%, Mg - 1.2%, B - 0.6%, Mn - 0.1% Cr. As a result, welding strength was about twice of Al - Mg - Si group alloy, and about thrice of pure Al group. In a storage manufactured from normal aluminium alloy (not containing B), only 20 fuels may be stored in one storage, but in a storage manufactured from alloy of the present invention, nuclear reaction will no re-occur even if 30 fuels are stored therein. (Kamimura, M.)

  17. The Effect of Processing Parameters and Alloy Composition on the Microstructure Formation and Quality of DC Cast Aluminium Alloys

    OpenAIRE

    Jaradeh, Majed

    2006-01-01

    The objective of this research is to increase the understanding of the solidification behaviour of some industrially important wrought aluminium alloys. The investigation methods range from direct investigations of as-cast ingots to laboratory-scale techniques in which ingot casting is simulated. The methods span from directional solidification at different cooling rates to more fundamental and controlled techniques such as DTA and DSC. The microstructure characteristics of the castings have ...

  18. Impact toughness improvement of high-strength aluminium alloy by intrinsic and extrinsic fracture mechanisms via hot roll bonding

    International Nuclear Information System (INIS)

    A multilayer aluminium laminate comprising 10 layers of Al-Zn-Mg-Cu alloy (82 vol.%) and nine layers of pure aluminium (18 vol.%) has been processed by hot rolling. The rolled laminate was characterized by electron backscattering diffraction, Charpy impact and shear tests. The multilayer laminate showed an outstanding Charpy impact toughness, which was 18 times higher than that for the as-received Al-Zn-Mg-Cu alloy. The improvement in damage tolerance was due to the high volume fraction of the high-strength aluminium and extrinsic fracture mechanisms.

  19. Corrosion Inhibitive Effect of Ocimum Gratissimum Extract on Zinc - Aluminium Alloy in Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    Mojisola O. Nkiko

    2011-11-01

    Full Text Available The inhibitive effect of Ocimum gratissimum by seed extract on the corrosion of zinc - aluminium (ZA alloy in 2 M hydrochloric acid (HCl solution has been studied using gravimetric methods. Inhibition increases with concentration of extract but decreases with temperature. This observation implies that Ocimum gratissimum seed extract is an effective and non toxic inhibitor of the corrosion of zinc - aluminium alloy. Adsorption of the extract on the surface obeyed the Freundlich adsorption isotherm. The calculated rate constant (k shows a first order kinetics in the absence and presence of the inhibitor. The kinetic parameter B, measured for the reaction has a high negative value which implies that Ocimum gratissimum becomes more effective as the temperature increases. Synergistic effect of halide additives shows an increase in the efficiency of the extract. However synergism parameter shows that synergism of halide additives decreases with increased concentration of inhibitor.

  20. Development of Cube Recrystallisation Texture and Microstructure of an Aluminium Alloy Suitable for Cartridge Case Manufacturing

    Directory of Open Access Journals (Sweden)

    Prantik Mukhopadhyay

    2010-04-01

    Full Text Available Electron backscattered diffraction investigations on just fully recrystallised orientation image microstructures, showed that the cube-oriented grains had the largest size in all microstructures of an aluminium alloy, which have potential use in the cartridge case manufacturing for defence purpose. The simulation of cube microstructure and texture of that aluminium alloy was tried. The recrystallisation texture and microstructure simulation by the 3-D cellular automaton model with the consideration of highest mobility of 40º<111> grainboundary, predicted the volume fraction of the cube texture orientation which was validated by experiment.Defence Science Journal, 2010, 60(3, pp.330-336, DOI:http://dx.doi.org/10.14429/dsj.60.361

  1. Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    E. Matykina

    2010-01-01

    Full Text Available The corrosion rate of AZ31, AZ80, and AZ91D magnesium/aluminium alloys immersed in 3.5 wt.% NaCl was determined comparing gravimetric and electrochemical measurements. The findings revealed that, for all investigated materials, a fraction of the metallic surface exposed to the corrosive medium did not reveal a normal electrochemical response to the applied signal. This may be associated with phenomena such as partial disintegration of specimens into fine metallic particles, electrochemical formation of Mg+ ions, and/or anomalous chemical attack occurring simultaneously with the normal electrochemical corrosion attack. The abnormal electrochemical behaviour was more evident for lower amounts of aluminium in the bulk composition of the investigated materials. Thus, the electrochemical estimates of pure Mg and the AZ31 alloy were not reliable and tended to underestimate corrosion losses.

  2. Corrosion behaviour of magnesium/aluminium alloys in 3.5 wt.% NaCl

    International Nuclear Information System (INIS)

    Corrosion behaviour of commercial magnesium/aluminium alloys (AZ31, AZ80 and AZ91D) was investigated by electrochemical and gravimetric tests in 3.5 wt.% NaCl at 25 deg. C. Corrosion products were analysed by scanning electron microscopy, energy dispersive X-ray analysis and low-angle X-ray diffraction. Corrosion damage was mainly caused by formation of a Mg(OH)2 corrosion layer. AZ80 and AZ91D alloys revealed the highest corrosion resistance. The relatively fine ?-phase (Mg17Al12) network and the aluminium enrichment produced on the corroded surface were the key factors limiting progression of the corrosion attack. Preferential attack was located at the matrix/?-phase and matrix/MnAl intermetallic compounds interfaces

  3. Corrosion Inhibitive Effect of Ocimum Gratissimum Extract on Zinc - Aluminium Alloy in Hydrochloric Acid

    Scientific Electronic Library Online (English)

    Mojisola O., Nkiko; Janet T., Bamgbose.

    2011-11-01

    Full Text Available The inhibitive effect of Ocimum gratissimum by seed extract on the corrosion of zinc - aluminium (ZA) alloy in 2 M hydrochloric acid (HCl) solution has been studied using gravimetric methods. Inhibition increases with concentration of extract but decreases with temperature. This observation implies [...] that Ocimum gratissimum seed extract is an effective and non toxic inhibitor of the corrosion of zinc - aluminium alloy. Adsorption of the extract on the surface obeyed the Freundlich adsorption isotherm. The calculated rate constant (k) shows a first order kinetics in the absence and presence of the inhibitor. The kinetic parameter B, measured for the reaction has a high negative value which implies that Ocimum gratissimum becomes more effective as the temperature increases. Synergistic effect of halide additives shows an increase in the efficiency of the extract. However synergism parameter shows that synergism of halide additives decreases with increased concentration of inhibitor.

  4. Age hardening of the aluminium alloy EN 4017

    OpenAIRE

    Swanepoel, D.B.; Stumpf, Waldo E.

    2009-01-01

    Hulamin Rolled Products (Ltd) developed a high Mn and Si containing alloy, EN 4017 as a scrap consuming alloy from the waste generated in producing their range of clad products for brazing of inter alia automotive heat exchangers. The multifaceted composition of this alloy (Al -1.2 wt% Si -1.1 wt% Mn -0.2 wt% Mg -0.26 wt% Cu) suggested that it might display some degree of strengthening via precipitate formation of the Mg2Si-types. The aging isotherms constructed showed that EN 4017 with...

  5. A study of the relationship between precipitate structure and chemistry on the mechanical properties of aluminium alloys

    OpenAIRE

    Warren, Paul

    1993-01-01

    ?The microstructural chemistry of the commercial aluminium alloy 7150, containing Al, Zn, Mg, Cu and some trace impurities, was investigated in detail. This alloy is a precipitation hardening alloy, deriving most of its strength from the fine distribution of solute rich precipitates formed during thermal processing. At peak strength this alloy suffers from the common problem of stress corrosion cracking, leading to unpredictable premature failure in the presence of a corrosiv...

  6. Investigation on the Change Effected by the Tool Type on the Hardness of Friction Stir Processed AA6063 Aluminium Alloy

    OpenAIRE

    K. Ganesa Balamurugan; D. Peter Pushpanathan; K. Mahadevan

    2012-01-01

    Aluminium alloy 6063 is one of the most popular alloys in the 6000 series which provides good extrudability and surface finish. Various application of this alloy include architectural and building products, electrical components and conduit, pipes for irrigation systems, door and window frames, railings and furniture, etc. However improving its strength by improving the hardness would complement the existing advantages of this alloy. This study was intended to improve the hardness of this all...

  7. Ultrafine-grained aluminium alloys prepared by severe plastic defomation (ECAP).

    Czech Academy of Sciences Publication Activity Database

    Dám, Karel

    Leoben : The Austrian Society for Metallurgy and Materials, 2011, 203-207. ISBN 978-3-200-02155-6. [International student´s day of Metallurgy /18./. Leoben (AT), 17.03.2011-19.03.2011] R&D Projects: GA AV ?R KAN300100801 Institutional research plan: CEZ:AV0Z10100520 Keywords : Equal-Chanel Angular Pressing * aluminium alloys * grain refinement Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. Quench factor analysis of aluminium alloys using the Jominy End Quench technique

    OpenAIRE

    Dolan, G. P.; Flynn, R. J.; Tanner, D. A.; Robinson, J. S.

    2005-01-01

    Determination of the time-temperature property C curve for aluminium alloys usually involves a large number of quenches and isothermal holds to calibrate a set of constants that describes the shape of the C curve for a particular property. The authors have used the Jominy end quench test to minimise the amount of work required for this type of analysis. By matching the Vickers hardness at regular intervals along the length of the Jominy test specimen with cooling curves generated using finite...

  9. Thermal Analysis on Butt Welded Aluminium Alloy AA7075 Plate Using FEM

    OpenAIRE

    Pal Pandi, M.; Kannan, Dr R.

    2014-01-01

    Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat lo...

  10. Measurement and finite element prediction of residual stresses in aluminium alloy 7010 forgings

    OpenAIRE

    Tanner, D. A.

    1999-01-01

    The finite element code ABAQUS is used to simulate the quenching of aluminium alloy 7010 in an attempt to predict the residual stress distribution that develops in simple shapes. All of the thermal and mechanical property data is input into the ABAQUS code as a function of temperature. The problem is sub-divided into a heat transfer problem and a stress/displacement problem. The rate of heat transfer from the material is determined by using the finite element method to predict ...

  11. Heat line formation during roll-casting of aluminium alloys at thin gauges

    OpenAIRE

    Yun, M; Hunt, J; Edmonds, D.

    1993-01-01

    Heat line formation during roll-casting of aluminium alloys at thin gauges has been studied experimentally and numerically. It has been found that the thinner the strip, the less the risk of forming heat lines or the less severe the heat lines are should them form. This behaviour has been discussed in terms of the heat transfer between the strip and the roll within the contact region in the twin-roll casting process.

  12. Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys

    OpenAIRE

    Matykina, E.; Arrabal, R.; Merino, M. C.; Feliu, S.; Pardo, A.

    2010-01-01

    The corrosion rate of AZ31, AZ80, and AZ91D magnesium/aluminium alloys immersed in 3.5 wt.% NaCl was determined comparing gravimetric and electrochemical measurements. The findings revealed that, for all investigated materials, a fraction of the metallic surface exposed to the corrosive medium did not reveal a normal electrochemical response to the applied signal. This may be associated with phenomena such as partial disintegration of specimens into fine metallic particles, electrochemica...

  13. High-temperature mechanical properties of aluminium alloys reinforced with boron carbide particles

    International Nuclear Information System (INIS)

    The mechanical properties of particulate-reinforced metal-matrix composites based on aluminium alloys (6061 and 7015) at high temperatures were studied. Boron carbide particles were used as reinforcement. All composites were produced by hot extrusion. The tensile properties and fracture analysis of these materials were investigated at room temperature and at high temperature to determine their ultimate strength and strain to failure. The fracture surface was analysed by scanning electron microscopy

  14. Dynamic Yield Strength and Spall Strength of Alumina Short Fiber Reinforced ZL109 Cast Aluminium Alloy

    OpenAIRE

    Zhang, R.; Wang, C.; Zhao, G.; Zeng, X.

    1997-01-01

    This paper describes the results of plate impact experiments conducted on a alumina short fiber reinforced ZL109 cast aluminium alloy. The loading was produced by a 100mm bore light gas gun. The metal-matrix composite specimen was backed with a PMMA. Manganin gauges were used to measure the normal stress history at the interface between the specimen and the PMMA. The dynamic yield strength and spall strength of the metal-matrix composite were determined.

  15. The magnitude of heat treatment induced residual stresses and the thermal stress relief of aluminium alloys

    OpenAIRE

    Robinson, J. S.; Tanner, D.A

    2002-01-01

    To produce useful strengthening, precipitation hardenable aluminium alloys rely on rapid quenching from the solution heat treatment temperature to suppress the formation of coarse equilibrium second phases. An unavoidable consequence of the rapid quenching of thick sections is the severe thermal gradients that quickly develop in the material. The attendant inhomogeneous plastic flow can then result in the establishment of residual stresses. Established procedures exist to minim...

  16. On glass formation in rapidly solidified aluminium-based alloys

    International Nuclear Information System (INIS)

    Thermodynamic properties of the melts of several Al-Y and Al-Fe-Y alloys are studied by means of calibrated differential thermal analysis. The results can be used to optimize process parameters of rapid solidification which are important for glass formation in the Al-based alloys. Close examinations of the melt-spun alloys show that the process parameters, particularly the temperature of the melts, will influence not only the amorphicity and the chemical short range order but also the crystallization process of the glasses. A key point of glass formation in the Al-based alloys in found to be related to the content in the melts of certain amount of the intermetallic compounds which are gradually dissolved into the premelted ? Al matrix. (orig.)

  17. Tribological Properties of Aluminium 2024 Alloy Beryl Particulate MMC's

    Directory of Open Access Journals (Sweden)

    H.B. Bhaskar

    2012-12-01

    Full Text Available Metal Matrix Composites (MMCs are emerging as the most versatile materials for advanced structural, automotive, aviation, aerospace, marine, defense applications and other related sectors because of their excellent combination of properties. In the present investigation, Al2024-Beryl composites were fabricated by liquid metallurgy route by varying Weight Percentage (wt. % of reinforcement from 0 wt. % to 10 wt. % in steps of 2 wt. %. The dry sliding wear tests were conducted to examine the wear behavior of the Al2024 alloy and its composites. The sliding wear tests were conducted for various loads, speeds and sliding distances. The result reveals that wear rates of the composite is lower than that of the matrix alloy and friction coefficient was minimum when compared to monolithic alloy. The incorporation of beryl particles as reinforcement material in Al2024 alloy improves the tribological characteristics.

  18. Advances in aluminium alloy products for structural applications in transportation

    International Nuclear Information System (INIS)

    This paper describes the needs of the aviation and automotive markets for structural materials and presents examples of developments of aluminum alloy products to fill these needs. Designers of aircraft desire materials which will allow them to design lightweight, cost-effective structures which have the performance characteristics of durability and damage tolerance. Their needs are being met by new and emerging materials varying from Al-Li alloys for thick structure, high-strength plate and extrusions for wings, and new monolithic and aluminum-fiber laminates for fuselages. Increase in fuel economy because of lighter weight structure is the driving force for aluminum alloys in the automotive market, and cost is extremely important. Mechanical properties for automotive use also depend on the application, and corrosion resistance must be adequate. For ''hang-on'' components such as fenders and hoods, formability is typically the limiting mechanical property. Strength must be adequate to resist denting at a thickness which offers cost-effective weight savings over steel. Because formability often decreases with increasing yield strength, alloys which are highly formable in the T4 temper and which age harden during the paint bake operation were developed. Alloys such as 6009 and 6010 are now being challenged by 2008, 6111 and 6016. Body structure components must be made from materials which absorb energy and fail gracefully during a crash. Such components for an automotig a crash. Such components for an automotive space frame are being die cast from an Al-Si-Mg alloy. These ductile die castings are joined to thin 6XXX extrusions which must combine formability, strength, ductility and the ability to deform plastically on impact. Bumpers must combine strength and adequate formability; in the event that current alloys are inadequate for future needs, a new 7XXX alloy offers an improved combination of properties. (orig.)

  19. Advances in aluminium alloy products for structural applications in transportation

    OpenAIRE

    Staley, J.; Lege, D.

    1993-01-01

    This paper describes the needs of the aviation and automotive markets for structural materials and presents examples of developments of aluminum alloy products to fill these needs. Designers of aircraft desire materials which will allow them to design lightweight, cost-effective structures which have the performance characteristics of durability and damage tolerance. Their needs are being met by new and emerging materials varying from Al-Li alloys for thick structure, high-strength plate and ...

  20. Maeasurement of residual stress and microhardness of a welded aluminium alloy 5052-H32 using X-ray diffraction

    International Nuclear Information System (INIS)

    Aluminium alloy 5052-H32 is a material used for fuel and oil lines in aeroplanes. this paper describers the measurements of residual stress and microhardness of a welded aluminium alloy 5052-H32 using X-ray diffraction and vickers methods respectively. the welding electrode employed was pure tungsten with 60 ampre current and 1.6 mm filler metal diameter. The annelead aluminium data were taken on (422) diffraction peak at 5.10 and 15 mm from the welded centre. The results indicate that the residual stress in welded aluminium alloy 5052-H32 is affected by the distance from the welded centre and by the annealing temperature, the values of the microhardness are between 66.58 kg/mm2 and 79.02 kg/mm2. (author). 5 refs.; 6 figs

  1. On problem about nature of Portevin-le-Chatelier effect in irradiated aluminium alloys

    International Nuclear Information System (INIS)

    The influence of hardening return, deformation ageing and ?-irradiation on the Portevin-le-Chatelier effect in aluminium alloys: D16, D95, AK4, AK6 was investigated. It was shown, that the hardening temperature slightly influences on the discontinuous current nature, whereas the temperature and ageing on return causes the considerable changes of Portevin-le-Chatelier. It was shown that the irradiation of ?-quantum low doses causes the Portevin-le-Chatelier effect in natural-aged state of alloy and disappearance of its effect during the subsequent ageing or during the irradiation with high doses. 6 refs.; 4 figs.; 2 tables. (author)

  2. Analysis of intermetallic particles in AlSi1MgMn aluminium alloy

    OpenAIRE

    G. Mrówka-Nowotnik; J. Sieniawski; M. Wierzbi?ska

    2007-01-01

    Purpose: The main objective of this study was to analyze the morphology and composition of complexmicrostructure of the intermetallic phases in AlSi1Mg alloy.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy(LM), transmission (TEM) and scanning (SEM) electron microscopy in combination with X-ray analysis (EDS)using polished sample, and X-ray diffraction (XRD) to identify intermetallics in AlSi1MgMn aluminium alloy.Findings: The results sho...

  3. Precipitation hardening of cast Zr-containing A356 aluminium alloy

    International Nuclear Information System (INIS)

    The effect of small additions of zirconium on the hardness, grain size, precipitate type and size of cast A356 aluminium alloy was investigated. The cast alloys were solution treated and then artificially aged for different periods of time. Hardness tests and scanning electron microscope (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) studies were carried out on the as-cast, as-solutionised and age-hardened specimens. Incoherent, coarse Al3Zr particles formed in the microstructure during the solidification of the alloy and caused grain refinement in the as-cast structure. These particles dissolved and reprecipitated as smaller-size particles during the solution treatment, causing the hardness of the alloy to remain constant at high temperatures for long periods of time due to the slow diffusion of Zr in the ?-Al.

  4. Development of electron beam welding of 6061-T6 aluminium alloy for the Jules Horowitz Reactor - Development of the electron beam welding of the 6061-T6 aluminium alloy

    International Nuclear Information System (INIS)

    In a text and in a Power Point presentation, the author first evokes the interesting properties of the 6061-T6 aluminium alloy and the problems its raises as far as welding is concerned. He also evokes that hundreds of tests and characterizations (destructive and non destructive testing) of TIG, MIG and EB (electron beam) welding processes have been performed before the selection of the electron beam welding process. The author discusses the weldability of aluminium alloys, and more particularly that of the 6061-T6 alloy (control of mechanical properties of the welded joint, hot cracking during welding, solidification or liquation)

  5. Study on segregation of aluminium-uranium alloys

    International Nuclear Information System (INIS)

    The relations between alloy solidification and solute segregation were considered. The solidification structure and the solute redistribution during the solidification of alloys with dendritic micro morphology were studied. The macro and micro segregation theories were reviewed. The mechanisms that could change the solidification structure were taken into account in the context of more homogeneous alloy production. Aluminum alloys solidification structures and segregation were studied experimentally in the 13 to 45% uranium range, usually considering solidification in static molds. The uranium alloys with up to 20% uranium were studied both for solidification in ingot molds and for controlled directional solidification. It was verified that these alloy compositions had structures similar to those of hipoeutectic alloys, showing an a phase with dendritic morphology and inter dendritic eutectic. For the alloys with more than 25% uranium, it was observed the formation of UAl3 and UAl4 phases with dendritic morphology. The dendritic UAl3, phase morphology was affected both by the solute concentration in the alloy and by the growth rate. The dendritic UAl3 phase non-singular aspect could be destroyed with decrease of the alloy solute concentration. In the alloys obtained with higher cooling rates it was found a tendency for the formation of substantial quantities of equi axial crystals of the solute enriched phases in the central regions of the ingot upper half. In the more external regions it was observed dendritic growth of these phases, for alloy compositions with over 25% uranium. An adequate reduction in the cooling rate changed the solidification structure form and distribution, as well as the segregation type and intensity. The uranium content in the solidified macro structures is presented as a function of: cooling rate, superheating, mold size, mold form and its temperature, number of remelting and time for the melt homogenization and agitation. It was observed that the uranium concentration gradient increased with the deviation from the eutectic composition. The cooling rate reduction promoted horizontal segregation of the uranium, decreasing its vertical segregation. It was shown that the stability regions of certain structure forms found in the ingot could be obtained as a function of the growth rate and solute concentration. The uranium segregation for the alloys obtained with higher cooling rates, was anticipated for al-1 the compositions studied using the inverse segregation theory. The positive segregation in the ingot higher regions appeared when, in the solidification initial stages, it occurred nucleation and growth of crystals in a quantity larger than that corresponding to equilibrium. These particles moved later to the central axis of the ingot higher regions during the solidification in the ingot molds. The origin of the negative segregation close to the cooled ingot faces is due to two mechanisms: 1) movement of solute depleted liquid in the channels of dendritic or equi axial phases in the direction of the cooled faces; 2) movement of solute enriched phases to the last regions to be solidified. The uranium normal segregation is analysed using the concept of solute rejection in front of a growth interface with dendritic micro morphology. It is assumed that the composition of the primary phase dendrites do not stay effectively in the K Q C o value. Therefore, this fact contributes also for the segregation. It is discussed the possibility of occurring liquid currents induced by density differences, dendritic interactions, decanting of the solute-rich inter dendritic liquid, and porosity, that may have affected the segregation intensity. The segregation at the eutectic temperature and the deposition of solute enriched phases are also analysed. (author)

  6. Phase-oriented surface segregation in an aluminium casting alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Chuong L. [Light Metals Research Centre, University of Auckland (New Zealand); Department of Chemistry, University of Auckland (New Zealand); Atanacio, Armand [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation (Australia); Zhang, Wei [Light Metals Research Centre, University of Auckland (New Zealand); Prince, Kathryn E. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation (Australia); Hyland, Margaret M. [Department of Chemical and Materials Engineering, University of Auckland (New Zealand); Metson, James B., E-mail: j.metson@auckland.ac.nz [Light Metals Research Centre, University of Auckland (New Zealand); Department of Chemistry, University of Auckland (New Zealand)

    2009-02-15

    There have been many reports of the surface segregation of minor elements, especially Mg, into surface layers and oxide films on the surface of Al alloys. LM6 casting alloy (Al-12%Si) represents a challenging system to examine such segregation as the alloy features a particularly inhomogeneous phase structure. The very low but mobile Mg content (approximately 0.001 wt.%), and the surface segregation of modifiers such as Na, mean the surface composition responds in a complex manner to thermal treatment conditions. X-ray photoelectron spectroscopy (XPS) has been used to determine the distribution of these elements within the oxide film. Further investigation by dynamic secondary ion mass spectrometry (DSIMS) confirmed a strong alignment of segregated Na and Mg into distinct phases of the structure.

  7. Experimental research on the ultimate strength of hard aluminium alloy 2017 subjected to short-time radioactive heating

    International Nuclear Information System (INIS)

    Highlights: ? Ultimate strength at transient heating is critical to security design of missiles. ? We measure the ultimate strength of alloy 2017 subjected to transient heating. ? Experimental results at transient heating are lacking in strength design handbook. ? Ultimate strength of alloy 2017 experimented is much higher than handbook value. ? The results provide a new method for optimal design of high-speed flight vehicles. -- Abstract: Alloy 2017 (Al–Cu–Mg) is a hard aluminium alloy strengthened by heat treatment. Because of its higher strength, finer weldability and ductility, hard aluminium alloy 2017 has been widely used in the field of aeronautics and astronautics. However, the ultimate strength and other characteristic mechanical parameters of aluminium alloy 2017 in a transient heating environment are still unclear, as these key mechanical parameters are lacking in the existing strength design handbook. The experimental characterisation of these critical parameters of aluminium alloy 2017 is undoubtedly meaningful for reliably estimating life span of and improving safety in designing high-speed flight vehicles. In this paper, the high-temperature ultimate strength, loading time and other mechanical properties of hard aluminium alloy 2017 under different transient heating temperatures and loading conditions are investigated by combining a transient aerodynamic heating simulation system and a material testing machine. The experimental results reveal that the ultimate strength and loading capability of aluminium alloy 2017 subjected to transient thermal heating are much higher than those tested in a long-time stable high-temperature environment. The research of this work not only provides a substantial basis for the loading capability improvement and optimal design of aerospace materials and structures subject to transient heating but also presents a new research direction with a practical application value.

  8. Aluminium casting alloy for high strength/high temperature applications

    International Nuclear Information System (INIS)

    This patent describes an aluminum alloy. It comprises by weight the following: 7.0-13.0% copper, 0.4-1.2% manganese, 0.21-0.40% vanadium, 0.31-0.70% zirconium, impurities limited as follows: generally equal amounts silicon and iron with Fe less than 0.8% and Si less than 0.6%, up to 0.2% Zn, up to 0.1% Mg, up to 0.2% Ni, the remainder being essentially aluminum, the alloy having a tensile strength of 33 ksi or greater when exposed to a temperature of 500 degrees F for at least 1000 hours

  9. Structural aluminium base alloy having excellent neutron shielding effect

    International Nuclear Information System (INIS)

    Purpose: To obtain a neutron shielding material composed of an aluminum base alloy excellent in weldability, erosion resistance, workability and mechanical strength. Constitution: An aluminum base alloy comprising 0.4 - 2.4% B, 0.3 - 2.0% Mg, 0.2 - 1.8% Sn, and balance of Al and impurities, and additionally containing optional components selected from Fe, Co, Ni, Cr, Mn, Zr, Ti, V, Mo, W, Zn and Cu each in 0.05 - 0.7% is used as a structural material for a nuclear reactor and a spent fuel storage house. (Furukawa, Y.)

  10. Influence of vibrations under bending on fatigue strength of titanium and aluminium alloys in case of repeatedly-statical tension

    International Nuclear Information System (INIS)

    High-frequency vibraions under bending are studied for their effect on repeatedly-statical tension of titanium and aluminium alloys. It is established that application of additional vibrations results in the loss of strength in the material, which manifests in a decrease of a cyclic life. The experiments are accomplished on titanium alloys VT6, VT14 and OT4

  11. On the friction stir welding of aluminium alloys EN AW 2024-0 and EN AW 5754-H22

    Directory of Open Access Journals (Sweden)

    C. Ozarpa

    2007-01-01

    Full Text Available Purpose: Purpose of this paper is investigate the friction stir welding capability of the EN AW 2024-0 and EN AW 5754-H22 Al alloys are studied, because two aluminium alloys are widely used in the industry and friction stir welding is getting widened to be used to join the aluminium alloys.Design/methodology/approach: Friction stir welding (FSW is a new solid fhase technique invented and patented for aluminium alloys. EN AW 2024-0 and EN AW 5754-H22 are aluminium alloys can be welded by fusion welding, but many welding problems arises from fusion welding. While the friction stir welding is a solid state welding process, some problems may be prevented.Findings: It is found in the course that these two aluminium alloys can be friction stir welded if fhe welding parameters are carefully selected. Hardness value in weld area for EN AW 2024-0, there is an increase about 10-40 Hv. Because of this is recrystalization and getting smaller grains. For EN AW 5754-H22 there is a decrease of hardness value because of recrystalization. Welding performance of EN AW 2024-0 is reached to 96.6 %. This value is 57 % for EN AW 5754-H22. It is possible to perform dissimilar welding using different aluminium alloys. elding performance of dissimilar aluminium alloys EN AW 2024-0 and EN AW 5754-H22 is reached a value of 66.39%.Research limitations/implications: Research limitations are that the design of the welding probe which is used in the experiments is changed, the speed of the welding can be improved. The material of the welding probe can be changed.Originality/value: The aluminium alloys EN AW 2024-0 and EN AW 5754-H22 are widely used ones but the friction stir weldability is not investigated so far. It is found that if the welding parameters are carefully selected, these aluminium alloys can be friction stir welded succesfuly.

  12. Continuous cooling transformation diagrams for 6XXX aluminium alloys

    International Nuclear Information System (INIS)

    Continuous cooling transformation diagrams of aluminum solid solution decomposition in range of cooling rates 100-1900 deg. C/h were built for some alloys of Al-Mg-Si-Fe system. Influence of cooling rate and chemical composition on temperatures of start and finish of solution decomposition was determined.

  13. Continuous cooling transformation diagrams for 6XXX aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bryantsev, P Yu, E-mail: p_bryant@rambler.ru [State Technological University, Moscow Institute of Steel and Alloys, 4 Leninskiy prospect, 119049, Moscow (Russian Federation)

    2009-09-15

    Continuous cooling transformation diagrams of aluminum solid solution decomposition in range of cooling rates 100-1900 deg. C/h were built for some alloys of Al-Mg-Si-Fe system. Influence of cooling rate and chemical composition on temperatures of start and finish of solution decomposition was determined.

  14. Castability tests applied to an aluminium-copper alloy

    International Nuclear Information System (INIS)

    Simplified castability tests were performed on an Al-2%Cu alloy. Measured values of the fluid length can be represented by Ragone's model, giving an estimate for the metal-mould heat transfer coefficient. The grain structure can be considered as a case of columnar-to-equiaxed transition in relatively simple flow conditions. (orig.)

  15. Age hardening of the aluminium alloy EN 4017

    Scientific Electronic Library Online (English)

    D.B., Swanepoel; W.E., Stumpf.

    2009-12-01

    Full Text Available Hulamin Rolled Products (Ltd) developed a high Mn and Si containing alloy, EN 4017 as a scrap consuming alloy from the waste generated in producing their range of clad products for brazing of inter alia automotive heat exchangers. The multifaceted composition of this alloy (Al -1.2 wt% Si -1.1 wt% M [...] n -0.2 wt% Mg -0.26 wt% Cu) suggested that it might display some degree of strengthening via precipitate formation of the Mg2Si-types. The aging isotherms constructed showed that EN 4017 with 0.19% Mg reached a lower peak strength (YS~210 MPa and UTS~260 MPa) compared to the EN 4017 material with 0.43% Mg (YS~270 MPa and UTS~325 MPa). The higher Mg variant of EN 4017 was comparable with the age-hardenable reference alloy EN 6061. Selected area electron diffraction (SAED) studies proved that the microstructure of age hardened EN 4017 contained a combination of B" and U2 phase after being aged at 175ºC for 65 h. The general microstructure contained precipitate free zones as well as grain boundary Si films, although these did not lead to significant embrittlement. The role of Mn dispersoids in the fracture mechanism of 4017 is also discussed. The article will compare the behaviour of EN 4017 with that EN 6061.

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

    International Nuclear Information System (INIS)

    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.

  17. Continuous cooling transformation diagrams for 6XXX aluminium alloys

    Science.gov (United States)

    Bryantsev, P. Yu

    2009-09-01

    Continuous cooling transformation diagrams of aluminum solid solution decomposition in range of cooling rates 100-1900 °C/h were built for some alloys of Al-Mg-Si-Fe system. Influence of cooling rate and chemical composition on temperatures of start and finish of solution decomposition was determined.

  18. Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate

    International Nuclear Information System (INIS)

    Graphical abstract: Scanning electron micrographs of microtomed surface shows pristine surface free of corrosion related 'mud cracking' inset for an inhibited AA7050 specimen when only 150 ppm Ce(dpp)3 is present in 0.1 M NaCl solution. Display Omitted Research highlights: ? The thin film of hydrolysis products of Ce(dpp)3 and aluminium oxide is proposed to cause the inhibition. ? The film consists of discrete Ce rich particles and a thin film over the matrix of Ce, P and Al oxides. ? Discrete deposition of Ce is specifically influenced by Cu rich intermetallics. - Abstract: Cerium diphenyl phosphate (Ce(dpp)3) has previously been shown to be a strong corrosion inhibitor for aluminium-copper magnesium alloy AA2024-T3 and AA7075 in chloride solutions. Surface characterisation including SEM and ToF-SIMS coupled with electrochemical impedance spectroscopy (EIS) measurements are used to propose a mechanism of corrosion inhibition which appears to involve the formation of a complex oxide film of aluminium and cerium also incorporating the organophosphate component. The formation of a thin complex film consisting of hydrolysis products of the Ce(dpp)3 compound and aluminium oxide is proposed to lead to the observed inhibition. SEM analysis shows that some intermetallics favour the creation of thicker deposits predominantly containing cerium oxide compounds.

  19. A vertical type twin roll caster for an aluminium alloy clad strip

    Directory of Open Access Journals (Sweden)

    T. Haga

    2013-07-01

    Full Text Available Purpose: of this paper: Twin roll casters that can cast two layers and three layers clad strip of aluminium alloys were invented. One of the purposes of this paper is to report that the two layers and three layers clad strip could be cast by the twin roll caster of this study. The investigation of the characters of these casters and the clad strips was purpose of this paper, too. The connecting at the interface between the strips was most important in the casting of the clad strip. Therefore, the attention was paid on the conditions of the interface. Design/methodology/approach: A vertical type tandem twin roll caster and a twin roll caster equipped with a scraper were designed, assembled and tested. Castings of the two layers clad strip and the three layers clad strip directly from molten metal were tried using these twin roll casters. The connecting strength between strips was investigated by the continuous bending test and the cold rolling. The diffusion and re-melting at the interface was investigated by the SEM-EPMA.Findings: The twin roll casters invented in this study could cast the two layers and three layers clad strips directly from molten metal. These clad strips had clear interface between the strips. This means that the mixing of the two alloys did not occur at the interface. The diffusion of elements of the each strip into another strip did not occur at the interface. The connecting strength was enough to endure the peeling at the interface by continuous bending. The clad ratio could be controlled by the solidification length up to 10:1. Two layers clad strip assembled from Al-Mg alloy strip and another aluminium alloy strip could be cast without defect by the effect of the scraper. The three layers clad strip which base strip had lower melting point than that of the overlay strip could be cast.Practical implications: The three layers clad strip, which base strip is 3003 aluminium alloy and overlay strips are 4045 aluminium alloy, can be used for the brazing sheet of the radiator of the automobile. The twin roll caster of this paper could cast this type of clad strip. The process saving and the energy saving can be attain by the twin roll caster of this paper. The clad ratio between the base strip and the overlay strip was smaller than 10:1. Originality/value: The twin roll casters that could cast two and three layers clad strips were original invention. using the twin roll caster.

  20. Development of continuous cooling precipitation diagrams for aluminium alloys AA7150 and AA7020

    International Nuclear Information System (INIS)

    Highlights: • The DSC method was used for developing continuous cooling precipitation diagrams. • The quench-induced particles were observed by SEM for alloys AA7150 and AA7020. • There were more quench-induced particles in alloy AA7150. • Quench sensitivity of Al alloys can be evaluated by using the CCP diagrams. -- Abstract: Two commercial 7xxx series aluminium alloys with different solute contents and different quench-induced precipitation behaviour have been investigated by using a specialised differential scanning calorimetry (DSC) technique to record exothermal heat outputs during continuous cooling. Together with hardness testing and microstructural analysis, this DSC method was used to develop continuous cooling precipitation (CCP) diagrams for alloys AA7150 and AA7020. The results show that the total precipitation heat for each alloy decreases with increasing cooling rate. However, the excess specific heat at a given cooling rate in alloy AA7150 is much higher than that in alloy AA7020. It is evident that there are atleast three different quench-induced reactions in different temperature regimes for alloy AA7150 cooled at various linear cooling rates, but only equilibrium MgZn2 (?-phase) and Al2CuMg (S-phase) particles were observed by scanning electron microscopy (SEM). There are at least two main precipitation peaks that can be found for alloy AA7020, which correspond to Mg2Si and MgZn2 (?-phase). Furthermore, a method is developed to evaluate the quench sensitivity of an alloy based on a determination of the critical cooling rate. The maximum hardness values are reached at cooling rates that are faster than or similar to the critical cooling rate

  1. Gating System Design for Casting thin Aluminium Alloy (Al-Si Plates

    Directory of Open Access Journals (Sweden)

    Victor ANJO

    2013-11-01

    Full Text Available The main problems caused by improper gating are entrained aluminium oxide films, cuts and washes, low casting yield and entrapped gas. This study describes the design of a gating system to produce thin Aluminium cast alloy plates of different sizes and thicknesses of 4mm, 6mm, 8mm, and 10mm using the non-pressurized gating with ratio of 1:4:4 and green sand moulding technique. The gating design was based on the laws of fluid mechanics and empirical rules of gating for non ferrous metals. The equipments used for this experiment includes; a coal fired crucible furnace and an X-Ray machine. Materials used include; silica sand, clay, wood, glue and Aluminium alloy scraps. The experimental procedure involved: the gating design calculations, construction of wooden pattern and gating; using the wooden pattern and gating to produce the mould cavities and gating; melting, melt treatment and pouring of melt in the sand mould to produce the casting. The plate castings after removal from mould were visually examined for surface defects and after fettling and cleaning X-Ray radiography was used to find the internal soundness of the castings. From the results obtained in the experiment, it was found that there were no internal defects and quality castings were produced.

  2. Use of Waste Flyash in Fabrication of Aluminium Alloy Matrix Composite

    Directory of Open Access Journals (Sweden)

    Ajit Kumar Senapati

    2014-05-01

    Full Text Available Waste flyash from two different industries (named as type A and type B were utilized as reinforcement in fabricating aluminium alloy based matrix composites (AMC. The AMCs were fabricated by continuous stir-casting method in a bottom pouring furnace at 7000C. Casting was made in rectangular metal mould having dimension 250x20x45 mm3. Effect of adding different flyash contents were realized thorough various mechanical behaviour tests. For measuring mechanical properties such as Brinell hardness, impact strength, compression strength, tensile strength, and micro hardness of both the AMCs, samples were prepared as per the standards in the mechanical workshop. The flyash distributions in the AMCs were confirmed through microstructure examination conducted on image analyzer and scanning electron micrographs. Results revealed that there is a great effect of reinforcing different flyash in aluminium alloy matrix composites. Type B flyash gave more enhanced mechanical properties compared to type A flyash. Thus, selection of flyash for reinforcement was found one of the most important criteria for fabricating aluminium matrix composites.

  3. Creep properties of 7075 aluminium alloy under intermittent stressing

    International Nuclear Information System (INIS)

    AA-7075 aluminum alloys are being extensively used in aircraft structure and also as ultracentrifuge rotors. At times they are subjected to cyclic loading at high temperatures. We have investigated creep phenomena, under constant and intermittent stressing, of flow-turned AA-7075-T6 tubes of 1mm wall thickness using hydraulic pressure at 70 degree, maximum temperature to which a centrifuge rotor is usually subjected in operation. It has been concluded that AA-7075 under intermittent loading has lower creep rate than that at continuous loading due to the precipitation of G.P. Zones at a faster rate. These results are consistent with the theoretical expectations and are also in complete agreement with the observations made by other investigators on similar alloys. Such experiments can easily be used to forecast the life of an ultracentrifuge in uranium enrichment plant. (author)

  4. Effect of heat treatment on high strength aluminium silicon alloy

    International Nuclear Information System (INIS)

    To improve the mechanical properties of domestically manufactured motor cycle pistons, the modification of structure by heat treatment has been studied. Pistons were subjected to different heat treatment cycles and optimum parameters were determined. Optical microscopic techniques and mechanical testing have been employed to study the effect of heat treatment o the microstructure and mechanical properties. A comparison of the properties of the domestically manufactured and imported pistons has also been made. Aluminum Silicon based alloys have been widely used for the production of automobile pistons due to their promising features like low coefficient of thermal expansion, high strength and favorable tribological characteristics. These properties can be further modified by alloying and heat treatment. (author)

  5. Precipitation in an AA6111 aluminium alloy and cosmetic corrosion

    International Nuclear Information System (INIS)

    The near-surface deformed layer on AA6111 automotive closure sheet alloy, generated by mechanical grinding during rectification, has an ultrafine grain microstructure, of 50-150 nm diameter, and a sharp transition with the underlying bulk alloy microstructure. Grinding and heat treatment to simulate rectification and paint baking processes result in the nucleation and growth of ?20 nm diameter precipitates at grain boundaries within the near-surface deformed layer. High-resolution transmission electron microscopy has shown Q phase precipitates in the deformed layer, giving dramatically increased corrosion susceptibility compared with the bulk microstructure, and this is responsible for the rapid-onset filiform corrosion. Transmission electron microscopy of the corrosion attack showed directly that the mode of corrosion was intergranular and that the Q phase precipitates were preserved after the passage of the corrosion front

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

    Science.gov (United States)

    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. Dilatometer study of rapidly solidified aluminium-silicon based alloys

    International Nuclear Information System (INIS)

    Aluminum-Silicon alloys are sought in a large number of automotive and aerospace applications due to their low coefficient of thermal expansion and high wear resistance. The present study focused on structural transformations as a function of the temperature of rapidly solidified hypereutectic Al100-xSix (x = 12, 22 and 40) alloys. Different structures out of equilibrium have been obtained after casting in sand, graphite and copper moulds and by melt spinning. The retained Si content in supersaturated alpha Al and the precipitation of Si is discussed in the light of the dilatometer studies [1, 2, 3] complemented by metallographic microscopy, XRD and DSC [4] measurements. A Kissinger analysis was used to determine the activation energy for the precipitation of supersaturated Si content.

  8. TOUGHNESS AND HEAT TREATMENT. RELATIONSHIP IN A 2091 ALUMINIUM ALLOY

    OpenAIRE

    Hautefeuille, L.; Rahouadj, R.; Barbaux, Y.; Clavel, M.

    1987-01-01

    The 2091 alloy was tested to determine toughness levels with respect to heat treatment. A drastic decrease in fracture toughness was observed as a function of heat treatment. The occurence of such a toughness drop was clearly related to fracture modes : . Transgranular and intergranular precipitation and deformation modes were studied. The loss of grain boundary strength could be explained by the precipitation of the quasi crystalline phase T2

  9. Structural stability of the high-aluminium zinc alloys modified with Ti addition

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2012-01-01

    Full Text Available The subject of the paper is structural stability of the Zn-26 wt.% Al binary alloys doped with 2.2 wt.% Cu or 1.6 wt.% Ti addition. The structural stability of Zn-Al alloys with increased Al content is connected with stability of solid solution of zinc in aluminium ?', which is the main component of these alloys microstructure. Such a solution undergoes phase transformations which are accompanied, among others, by changes in dimensions and strength properties.The structural stability of the ZnAL26Cu2.2 and ZnAl26Ti1.6 alloys was investigated using XRD examinations during long term natural ageing after casting, as well as during long term natural ageing after super-saturation and quenching. On the basis of the performed examinations it was stated that small Ti addition to the binary ZnAl25 alloy, apart from structure refinement, accelerates decomposition of the primary ?' phase giving stable structure in a shorter period of time in comparison with the alloy without Ti addition. Addition of Ti in amount of 1.6 wt.%, totally replacing Cu, allows obtaining stable structure and dimensions and allows avoiding structural instability caused by the metastable ??CuZn4phase present in the ZnAl26Cu2.2 alloy.

  10. Anodic oxidation and dielectric behaviour of aluminium-niobium alloys

    International Nuclear Information System (INIS)

    The anodizing behaviour of sputtering-deposited Al-Nb alloys, containing 21, 31 and 44 at.% niobium, has been examined in 0.1 M ammonium pentaborate electrolyte with interest in the composition and the dielectric properties of the anodic oxides. RBS and TEM revealed amorphous oxides, containing units of Nb2O5 and Al2O3 in proportion to the alloy composition. Xenon marker experiments indicated their growth through migration of the Nb5+, Al3+ and O2- species, with cation transport numbers, in the range 0.31-0.35, and formation ratios, in the range 1.35-1.64 nm V-1, intermediate between those of anodic alumina and anodic niobia. Al3+ ions migrate slightly faster than Nb5+ ions, promoting a thin alumina layer at the film surface, although this layer is penetrated by fingers of the underlying niobium-containing oxide of relatively reduced ionic resistivity. The incorporation of units of Nb2O5 into anodic alumina increases the dielectric constant from about 9 to the range 11-22 for the investigated alloys

  11. WEAR STUDIES OF ALUMINIUM ZINC ALLOY METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    H.P.Varade

    2013-05-01

    Full Text Available In the present study, the effect of wear parameters like applied load, sliding velocity, sliding distance and weight percentage of Silicon Carbide on the dry sliding wear of the A l u m i n i u m Z i n c alloy metal matrix composites have been investigated experimentally. Wear tests of A l u m i n i u m Z i n c alloy metal matrix composites against AISI 1045 steel disc were carried out under dry sliding conditions using pinon- disc test machine. A plan of experiments, based on Taguchi method, was performed to acquire data incontrolled way and L27 orthogonal array along with the analysis of variance (ANOVA were employed to investigate the influence of process parameters on the wear of alloy composites. Multiple linear regression analysis was carried out to develop relation of amount of wear with applied load, sliding velocity, sliding distance and weight percentage of Silicon Carbide. Confirmation tests were conducted to verify the experimental results from the mentioned correlations.

  12. The solidification behavior of dilute aluminium-scandium alloys

    International Nuclear Information System (INIS)

    The solidification behavior of dilute Sc containing Al alloys has been investigated. In binary Al-Sc alloys, Sc additions greater than the eutectic composition (0.55 wt%) were found to produce a remarkable refinement in the grain size of aluminum castings, of two orders of magnitude, due to the formation of the primary Al3Sc intermetallic phase during solidification. The refinement in grain size only occurred in hypereutectic compositions and was shown to be far greater than can be achieved by conventional Al grain refiners. Grain refinement by the addition of Sc is accompanied by a change in growth morphology from dendritic, in the large unrefined grains, to fine spherical grains with a divorced eutectic appearing on the grain boundaries in the refined castings. Similar levels of refinement were observed in Al-Sc-Zr and Al-Cu-Sc alloys. In the latter, a change in the segregation behavior of Cu was observed, from a strongly interdendritic segregation pattern to a more homogeneous distribution. The supersaturated Al-Sc solid solution can decompose via a discontinuous precipitation reaction to form coherent rod-like precipitates of the L12 Al3Sc phase

  13. Effect of pulsed current welding on fatigue behaviour of high strength aluminium alloy joints

    International Nuclear Information System (INIS)

    High strength aluminium alloys (Al-Zn-Mg-Cu alloys) have gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminium alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 6 mm thickness have been used as the base material for preparing single pass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt%)) grade aluminium alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW) and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Fatigue properties of the welded joints have been evaperties of the welded joints have been evaluated by conducting fatigue test using rotary bending fatigue testing machine. Current pulsing leads to relatively finer and more equi-axed grain structure in gas tungsten arc (GTA) and gas metal arc (GMA) welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Grain refinement is accompanied by an increase in fatigue life and endurance limit

  14. Tensile behavior of dissimilar friction stir welded joints of aluminium alloys

    International Nuclear Information System (INIS)

    The heat treatable aluminium alloy AA2024 is used extensively in the aircraft industry because of its high strength to weight ratio and good ductility. The non-heat treatable aluminium alloy AA5083 possesses medium strength and high ductility and used typically in structural applications, marine, and automotive industries. When compared to fusion welding processes, friction stir welding (FSW) process is an emerging solid state joining process which is best suitable for joining these alloys. The friction stir welding parameters such as tool pin profile, tool rotational speed, welding speed, and tool axial force influence the mechanical properties of the FS welded joints significantly. Dissimilar FS welded joints are fabricated using five different tool pin profiles. Central composite design with four parameters, five levels, and 31 runs is used to conduct the experiments and response surface method (RSM) is employed to develop the model. Mathematical regression models are developed to predict the ultimate tensile strength (UTS) and tensile elongation (TE) of the dissimilar friction stir welded joints of aluminium alloys 2024-T6 and 5083-H321, and they are validated. The effects of the above process parameters and tool pin profile on tensile strength and tensile elongation of dissimilar friction stir welded joints are analysed in detail. Joints fabricated using Tapered Hexagon tool pin profile have the highest tensile strength and tensile elongation, whereas the Straight Cylinder tool pin profile have the lowest tensile strength and tensile elongation. The results are useful to have a better understanding of the effects of process parameters, to fabricate the joints with desired tensile properties, and to automate the FS welding process.

  15. Fabrication of MEMS components using ultrafine-grained aluminium alloys

    International Nuclear Information System (INIS)

    A novel process for the fabrication of a microelectromechanical systems (MEMS) metallic component with features smaller than 10 µm and high thermal conductivity was investigated. This may be applied to new or improved microscale components, such as (micro-) heat exchangers. In the first stage of processing, equal channel angular pressing (ECAP) was employed to refine the grain size of commercial purity aluminium (Al-1050) to the ultrafine-grained (UFG) material. Embossing was conducted using a micro silicon mould fabricated by deep reactive ion etching (DRIE). Both cold embossing and hot embossing were performed on the coarse-grained and UFG Al-1050. Cold embossing on UFG Al-1050 led to a partially transferred pattern from the micro silicon mould and high failure rate of the mould. Hot embossing on UFG Al-1050 provided a smooth embossed surface with a fully transferred pattern and a low failure rate of the mould, while hot embossing on the coarse-grained Al-1050 resulted in a rougher surface with shear bands.

  16. Wear Properties of Alumina Particles Reinforced Aluminium Alloy Matrix Composite

    Directory of Open Access Journals (Sweden)

    Faiz Ahmad

    2011-01-01

    Full Text Available In this study results of wear and friction coefficient of alumina particles reinforced Aluminium Matrix Composite (AMCs were presented. The wear of AMCs was tested against the brake pad material under various loads ranging from 50 to 200 N at fixed speed of 600 rpm. A pin on-disk apparatus was used for measurement of wear rate of AMCs and resulting microstructure at each load was examined under scanning electron microscope. The coefficient of friction was also measured for corresponding loading conditions studied. Results showed an increased wear rate of AMCs with increased load and decrease in friction coefficient. Micro structural analysis of AMCs showed a combination of adhesive and abrasive types of wear for sample tested at loads. The reduction in coefficient of friction was noted as the surface of AMCs became rougher tested at higher load. This was related to the removal of alumina particles from the surface of AMCs during wear test at higher load that rough reduced coefficient of friction.

  17. Temperature Influence and straining in condition of creep on phase distribution in aluminium alloy D16

    International Nuclear Information System (INIS)

    In the current work research results of simultaneous action of temperature and straining in mechanical testing conditions on creep up to destruction stage on phase redistribution in industrial aluminium alloy D16 were presented. Purpose of the work is a forecasting of the material behavior in the long operation process in complicated temperature-strain conditions. It is determined, that in the S-phase alloy relative distribution separation and poses size up to ?6 ?m have been observed. In the result of processing on homogenous solid solution the coagulation of S-separation takes place. After testing of the alloy on creep the phase separation of Al7FeCu2, and Cu3Al2 and FeSi2 in small amounts were revealed

  18. The study of iron carbon and aluminium magnesium alloys by internal friction at medium frequency

    International Nuclear Information System (INIS)

    Automatic internal friction measuring devices, their manufacture, and use in studying iron carbon and aluminium magnesium alloys are described. A brief review of the theory of internal friction in metals is given. A comparative study of various mechanical and electronic measuring devices is made. A flexing apparatus and a torsion balance, both permitting automatic measurements, are presented. Dilute carbon iron alloys were studied. The reorientation of the carbon and the precipitation kinetics were studied as a function of the purity-of the iron, the quenching rate and the ageing temperature. The results are interpreted in terms of the theories of Wert and Zener and then those of Damask, Danielson and Dienes. A systematic study was made of internal friction in Al Mg alloys at various frequencies with different magnesium contents, thermal treatments, and deformations. (author)

  19. An aluminium alloy for a non breeding blanket NET/INTOR

    International Nuclear Information System (INIS)

    All existing commercially available Al alloys contain a sufficient quantity of impurities, such as Fe, Ni, Mn, Zn..., so their activity is important. These materials should not be used in NET/INTOR first wall/blanket structures. In order to achieve low residual radioactivity a new alloy, based on a very high purity aluminium (99.995) and high purity alloying elements selected from the few low activity elements such as Mg, Si, V, C, N and O, has been developed by the authors. The major features (property area: mechanical, physical, chemical compatibility) of this material have been experimentally determined in order to evaluate it as a first wall material for NET/INTOR. (author)

  20. Quantitative study of the hardness property of laser surface alloyed aluminium AA1200

    Scientific Electronic Library Online (English)

    A.P.I., Popoola; S.L., Pityana; T., Fedotova; O.M., Popoola.

    2011-05-01

    Full Text Available Aluminium AA1200 was laser alloyed with a combination of nickel and titanium diboride using different weight ratios. Chemical reactions took place with the formation of different phases. The characterization of the alloyed surfaces was carried out by x-ray diffraction (XRD), optical and scanning ele [...] ctron microscopes. The alloyed surfaces are composed of the initial phase of Al-Ni dendrites and eutectics of TiB2/Al and TiB2/Ni distributed on the initial phase. Experimental results obtained showed that Al-Ni intermetallics brought about a significant increase in the hardness property of Al; however, these intermetallics are highly brittle and prone to fail by brittle fracture or stress corrosion cracking when put in service. The addition of TiB2 brought about a reduction in the formation of these intermetallic phases. A microhardness increase of over 10 times the hardness of the substrate was achieved.

  1. Coupled precipitation and yield strength modelling for non-isothermal treatments of a 6061 aluminium alloy

    International Nuclear Information System (INIS)

    In age-hardening alloys, high-temperature processes, such as welding, can strongly modify the precipitation state, and thus degrade the associated mechanical properties. The aim of this paper is to present a coupled approach able to describe precipitation and associated yield stresses for non-isothermal treatments of a 6061 aluminium alloy. The precipitation state (in terms of volume fraction and precipitate size distribution) is modelled thanks to a recent implementation of the classical nucleation and growth theories for needle-shaped precipitates. The precipitation model is validated through small-angle neutron scattering and transmission electron microscopy experiments. The precipitation size distribution is then used as an entry parameter of a micromechanical model for the yield strength of the alloy. Predicted yield stresses are compared to tensile tests performed with various heating conditions, representative of the heat-affected zone of a welded joint

  2. Monitoring precipitation kinetics in heat treatable aluminium alloys using in-situ resistivity in Gleeble thermomechanical simulator

    OpenAIRE

    Chobaut, Nicolas; Carron, Denis; Drezet, Jean-Marie

    2014-01-01

    A conventional way to determine precipitation kinetics in heat treatable aluminium alloys is to monitor the associated solute loss by in-situ resistivity. A Gleeble machine is used to perform so called isothermal quenching (IQ) resistivity measurements. IQ consists in quenching the alloy down to a given temperature and holding it at this temperature. The results are validated against measurements performed with a classical four-points method using continuous current on the same alloy.

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

    Science.gov (United States)

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

    2015-04-01

    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 H2O, 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°.

  4. Helium-4 and neutron activation analysis for phosphorus in aluminium-silicon alloys

    International Nuclear Information System (INIS)

    An instrumental determination of phosphorus in aluminium-silicon alloys by activation with 20-MeV helium-4 particles can be based on the 31P(?,n)sup(34m)Cl reaction. A mixture of aluminium powder and disodium hydrogenphosphate is used as a standard. For concentrations ranging from 1.7 to 25 ?g g-1, the experimental standard deviation ranges from 1 to 24% with an average of 8%. The method was compared with thermal neutron activation analysis based on the 31P(n,?)32P reaction. 32P was chemically separated by precipitation as ammonium molybdophosphate. This technique yielded results with a standard deviation between 0.3 and 7.5% with an average of 2%. The agreement between the two methods was satisfactory. The results were also compared with photometry and atomic absorption spectrometry. (Auth.)

  5. Development of nano cerium oxide incorporated aluminium alloy sacrificial anode for marine applications

    International Nuclear Information System (INIS)

    Aluminium-zinc alloy sacrificial anodes are extensively used for cathodic protection. The performance of the sacrificial anodes can be significantly improved by incorporation of microalloying elements in the aluminium matrix. In the present work nano cerium oxide particles of different concentrations, ranging from 0 to 1 wt% were incorporated for activating and improving the performance of the anode. The electrochemical test results revealed the increased efficiency of the anode. The electrochemical impedance spectroscopy revealed the information that the presence of nano cerium oxide in the anode matrix caused effective destruction of the passive alumina film, which facilitated enhancement of galvanic performance of the anode. Moreover, the biocidal activity of cerium oxide prevented the bio accumulation considerably which enables the anodes to be used in aggressive marine conditions

  6. Corrosion behaviour of 2124 aluminium alloy-silicon carbide metal matrix composites in sodium chloride environment

    International Nuclear Information System (INIS)

    Aluminium alloy based particle reinforced metal matrix composites (MMCs) are being considered for a range of applications. Their mechanical properties have been investigated in detail, but more information about their corrosion resistance is needed. In this investigation, the corrosion behaviour of silicon carbide particulates (SiCp)-2124 aluminium metal matrix composites was studied in 3 wt% sodium chloride solution by means of electrochemical technique and optical microscope. The effects of weight percentages and particle size of silicon carbide particulates on corrosion behaviour of the composite were studied in NaCl and it was observed that corrosion rate increases linearly with the increasing weight percentage of SiCp. The corrosion rate of the MMC increases by increasing the size of SiC particles. Anodization improved corrosion resistance of the composites. (author)

  7. Determination of lattice orientation in aluminium alloy grains by low energy gallium ion-channelling

    Energy Technology Data Exchange (ETDEWEB)

    Silk, Jonathan R. [Aerospace Metal Composites Ltd., RAE Road, Farnborough, GU14 6XE (United Kingdom); Dashwood, Richard J. [WMG, University of Warwick, Coventry, CV4 7AL (United Kingdom); Chater, Richard J., E-mail: r.chater@imperial.ac.u [Department of Materials, Imperial College, London SW7 2AZ (United Kingdom)

    2010-06-15

    Polished sections of a fine-grained aluminium, silicon carbide metal matrix composite (MMC) alloy were prepared by sputtering using a low energy gallium ion source and column (FIB). The MMC had been processed by high temperature extrusion. Images of the polished surface were recorded using the ion-induced secondary electron emission. The metal matrix grains were distinguished by gallium ion-channelling contrast from the silicon carbide component. The variation of the contrast from the aluminium grains with tilt angle can be recorded and used to determine lattice orientation with the contrast from the silicon carbide (SiC) component as a reference. This method is rapid and suits site-specific investigations where classical methods of sample preparation fail.

  8. Determination of lattice orientation in aluminium alloy grains by low energy gallium ion-channelling

    International Nuclear Information System (INIS)

    Polished sections of a fine-grained aluminium, silicon carbide metal matrix composite (MMC) alloy were prepared by sputtering using a low energy gallium ion source and column (FIB). The MMC had been processed by high temperature extrusion. Images of the polished surface were recorded using the ion-induced secondary electron emission. The metal matrix grains were distinguished by gallium ion-channelling contrast from the silicon carbide component. The variation of the contrast from the aluminium grains with tilt angle can be recorded and used to determine lattice orientation with the contrast from the silicon carbide (SiC) component as a reference. This method is rapid and suits site-specific investigations where classical methods of sample preparation fail.

  9. Hydrogen analysis and effect of filtration on final quality of castings from aluminium alloy AlSi7Mg0,3

    OpenAIRE

    M. Br?na; A. Sládek

    2011-01-01

    The usage of aluminium and its alloys have increased in many applications and industries over the decades. The automotive industry is the largest market for aluminium castings and cast products. Aluminium is widely used in other applications such as aerospace, marine engines and structures. Parts of small appliances, hand tools and other machinery also use thousands of different aluminium castings. The applications grow as industry seeks new ways to save weight and improve performance and rec...

  10. Effect of Cathodic Adsorbed Hydrogen on Industrial Aluminium Alloy AA 5083 Corrosion Induced by Elemental Mercury in LNG Industries

    OpenAIRE

    D. Zerouali; Z. Derriche; M.Y. Azri

    2006-01-01

    Natural gases contain impurities such as mercury and water, which both act simultaneously and cause a significant corrosion of aluminium alloys constituting the cryogenic exchangers tubes used in the industries of natural gas liquifaction. Corrosion creates many problems of liquifaction units (Groningen (Holland), Skikda, Bethioua (Algeria). The process of corrosion begins with an adsorption of mercury on aluminium surfaces, the formation of an amalgam and an electrochemical oxidation of alum...

  11. Effect of friction time on the properties of friction welded YSZ?alumina composite and 6061 aluminium alloy

    OpenAIRE

    Basheer, Uday M.; Mn, Ahmad Fauzi; Ismail, A. B.; Zuhailawati, H.

    2012-01-01

    The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ) composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP) and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried ou...

  12. High speed twin roll casting of 6016 aluminium alloy strip

    Directory of Open Access Journals (Sweden)

    H. Sakaguchi

    2007-01-01

    Full Text Available Purpose: of this paper is to clear the possibility of high speed roll casting of aluminum alloy strip. In the bodyof the automobiles, a sheet of 6016 aluminum alloy is adopted for the outer panel. Therefore, casting of 6016was tried in this study. Characteristics of roll cast 6016 were investigated.Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designedto overcome the low castability of the twin roll caster.Findings: are as below. 6016 alloy could be cast into the strip continuously at the speed of 60m/min. Thethickness of the strip was 3.4 mm. The microstructure at as-cast and after T4 heat treatment was shown. Themicrostructure was very fine. The mechanical properties were investigated by the tensile test and 180 degreesvending test. The as-cast strip could be cold rolled without homogenization to 1mm. Result of tensile test wastensile strength was 230MPa, 0.2% proof stress was 118MPa and elongation was 33%. 6016 strip of T4 heattreatment could be bent 180 degrees without occurrence of crack at the outer surface or breaking.Research limitations/implications: is the width of the strip was 100 mm. It is necessary to test twin roll casterequipped wide rolls.Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheetmetal for the automobile. The low productivity of the twin roll caster could be improved.Originality/value: is that 6016 strip could be cast continuously at speed 60 m/min and this strip had goodmechanical properties.

  13. The microstructure and precipitation kinetics of a cast aluminium alloy

    International Nuclear Information System (INIS)

    The microstructure of a cast Al-Si-Cu alloy was studied quantitatively in detail by a combination of differential scanning calorimetry, scanning electron microscopy, scanning tunnelling microscopy and transmission electron microscopy. The kinetics of coarsening can be described by the classical ripening theory. The plot of the rate constant of coarsening and the temperature follows an Arrhenius behaviour with an activation energy of about 140.4 kJ/mol-1, which is approximately the activation energy for diffusion of Cu and/or Si in Al, indicating diffusion-controlled precipitate growth

  14. Evolution of texture and its influence on the failure of components in some aluminium alloys

    Science.gov (United States)

    Narayanan Parameswaran, Ramesh; Satyam, Suwas; Parmeshwar Prasad, Sinha; Srinivasa, Ranganathan

    2015-04-01

    This paper describes the evolution of crystallographic texture in three of the most important high strength aluminium alloys, viz., AA2219, AA7075 and AFNOR7020 in the cold rolled and artificially aged condition. Bulk texture results were obtained by plotting pole figures from X-ray diffraction results followed by Orientation Distribution Function (ODF) analysis and micro-textures were measured using EBSD. The results indicate that the deformation texture components Cu, Bs and S, which were also present in the starting materials, strengthen with increase in amount of deformation. On the other hand, recrystallization texture components Goss and Cube weaken. The Bs component is stronger in the deformation texture. This is attributed to the shear banding. In-service applications indicate that the as-processed AFNOR7020 alloy fails more frequently compared to the other high strength Al alloys used in the aerospace industry. Detailed study of deformation texture revealed that strong Brass (Bs) component could be associated to shear banding, which in turn could explain the frequent failures in AFNOR7020 alloy. The alloying elements in this alloy that could possibly influence the stacking fault energy of the material could be accounted for the strong Bs component in the texture.

  15. Oxidation behavior of FeCr and FeCrY alloys coated with an aluminium based paint

    Directory of Open Access Journals (Sweden)

    Marina Fuser Pillis

    2008-09-01

    Full Text Available A variety of metallic components rely on properties that are specific to the alloy and its surface. Coatings have been extensively used to protect metallic surfaces from the aggressive effects of the environment to which it is exposed. In this investigation, the high temperature oxidation behavior of a FeCr and a FeCrY alloy coated with an aluminium based paint has been studied. The objective was to form the more resistant alumina surface layer on an aluminium free alloy. Aluminium based paint coated and uncoated specimens of the two alloys were oxidized for up to 200 hours at 1000 °C in air. The oxidized specimens were examined in a scanning electron microscope coupled to an energy dispersive system and the surfaces were analyzed by X ray diffraction analysis. The aluminium based paint coating increased the oxidation resistance of the alloys, mainly over extended periods. The FeCrY alloy coated with the Al based paint exhibited the highest oxidation resistance.

  16. Oxidation behavior of FeCr and FeCrY alloys coated with an aluminium based paint

    Scientific Electronic Library Online (English)

    Marina Fuser, Pillis; Olandir Vercino, Correa; Edval Gonçalves de, Araújo; Lalgudi Venkataraman, Ramanathan.

    2008-09-01

    Full Text Available A variety of metallic components rely on properties that are specific to the alloy and its surface. Coatings have been extensively used to protect metallic surfaces from the aggressive effects of the environment to which it is exposed. In this investigation, the high temperature oxidation behavior o [...] f a FeCr and a FeCrY alloy coated with an aluminium based paint has been studied. The objective was to form the more resistant alumina surface layer on an aluminium free alloy. Aluminium based paint coated and uncoated specimens of the two alloys were oxidized for up to 200 hours at 1000 °C in air. The oxidized specimens were examined in a scanning electron microscope coupled to an energy dispersive system and the surfaces were analyzed by X ray diffraction analysis. The aluminium based paint coating increased the oxidation resistance of the alloys, mainly over extended periods. The FeCrY alloy coated with the Al based paint exhibited the highest oxidation resistance.

  17. Determination of corundum, spinel and aluminium nitride in scum on aluminium alloy melt by an X-ray diffractometric method combined with selective dissolution

    International Nuclear Information System (INIS)

    An X-ray diffractometric method has been developed for determination of corundum (?-Al2O3), spinel (MgAl2O4) and aluminium nitride in the scum formed on melt of aluminium alloy. In order to remove aluminium for improved resolution of analysis, the scum was subjected to selective dissolution; Hydrochloric acid (1+1) was used for the determination of corundum and spinel, and a bromine-methanol solution under ultrasonic agitation was used for that of aluminium nitride. Silicon powder of 1/5 in mass was added to the residue as a reference material. Ratios of the integral intensities of strong diffraction lines from the compounds to the peak intensity of silicon (111) diffraction line were measured. The compounds were determined with linear relations of regression between the intensity ratios and the concentrations of standard specimens. Corundum and spinel in the range of 18-28% and aluminium nitride in the range of 2-6% were determined with standard deviations (SD) of 0.7-2.4% and 0.2%, respectively; Corundum of 0.8% was determined with an SD of 0.1%. (author)

  18. Residual Stress Measurement of Coarse Crystal Grain in Aluminium Casting Alloy by Neutron Diffraction

    International Nuclear Information System (INIS)

    Full text: Neutron stress measurement can detect strain and stress information in deep region because of large penetration ability of neutron beams. The present paper describes procedure and results in the residual stress measurement of aluminium casting alloy by neutron diffraction. Usually, the aluminium casting alloy includes the large crystal grains. The existence of large crystal grains makes it difficult to estimate the residual stresses in highly accuracy. In this study, the modified three axial method using Hook's equation was employed for neutron stress measurement. These stress measurements were performed under the two kinds of new techniques. One is a rocking curve method to calculate the principal strains in three directions. The peak profiles which appear discretely on rocking curves were translated to principle stresses by the Bragg law and the basic elastic theory. Another is the consideration of measurement positions and the edge effect in the neutron irradiated area (volume gage). The edge effect generates the errors of 2?-peak position in the neutron stress measurement. In this study, the edge effect was investigated in detail by a small bit of copper single crystal. The copper bit was moved and scanned on three dimensionally within the gage volume. Furthermore, the average strains of symmetrical positions are measure by the sample turning at 180 degrees, because the error distributions of the 2?-peak position followed to positions inside the gage n followed to positions inside the gage volume. Form these results of this study, the residual stresses in aluminium casting alloy which includes the large crystal grains were possible to estimate by neutron stress measurement with the rocking curve method and the correction of the edge effect. (author)

  19. Modelling the processing of aluminium alloys in the semi-solid state

    Energy Technology Data Exchange (ETDEWEB)

    Wahlen, A. [ARC Leichtmetallkompetenzzentrum Ranshofen GmbH, Ranshofen (Austria)

    2002-07-01

    Thixoforming, an innovative technique in which metals are formed in their semi-solid state, permits the cost-efficient production of components with improved properties and performance compared to conventional pressure die casting. Since this process is still relatively new, great technical advances can be expected in the near future. These advances should allow production of near-net-shape components with good mechanical properties, combined with low manufacturing cost. Due to the distinct thixotropic flow pattern of the semi-solid slurry, high production speeds similar to those of conventional pressure die casting can be achieved, yet the disadvantages of the latter are eliminated: thixoformed components possess a good combination of strength and ductility, and they are heat-treatable and weldable. The requirement for thixotropic flow behaviour is a particular microstructure in the semi-solid state. At the onset of forming, the solid phase of the material must exhibit a globular morphology, a feature that can be produced with a novel casting technique called new rheocasting (NRC). Cast billets of several aluminium alloys and resulting microstructures show the feasibility of the chosen process variant. Constitutive models for the distinct flow behaviour of thixotropic aluminium alloys in the semi-solid state are derived with respect to temperature, strain rate and microstructure. Experimental techniques such as deformation tests, backward extrusion experiments, differential thermal analysis and quantitative metallurgy provide the necessary data to calibrate the materials models. For the implementation in a special-purpose FE software package, constitutive models for the thixotropic flow stress, the specific thixotropic flow stress, the specific heat capacity and the thermal conductivity of cast and wrought aluminium alloys in the semi-solid state are provided. For the optimization of the thixoforming manufacturing process these models were implemented in the FE software package ThixoForm. The simulation results were compared with industrial experiments and used for process control with the objectives of high-quality parts and maximum productivity. (orig.)

  20. Microstructure and properties of FSW joints of 2017A/6013 aluminium alloys sheets

    Directory of Open Access Journals (Sweden)

    K. Mroczka

    2008-10-01

    Full Text Available Purpose: The aim of the studies was to analyse the structure and mechanical properties of FSW joints. Experiment were perform in order to study possibilities to join different aluminium alloys 2017A and 6013. The alloys differ one from the other with respect to chemical composition and mechanical properties especially, therefore the ability to perform the correct joints may be useful for special constructions.Design/methodology/approach: The joints were produced applying different parameters and temperatures. The microstructure was studied using optical, scanning electron and transmission electron microscopes. The mechanical properties are discussed with regard to microhardness profiles on the cross-sections of the joints.Findings: No cracks were found in the joints. Weld nuggets were formed in the 2017A alloy which was located on the advancing side during welding. Mixing process of the materials within the joints was observed as a formation of separate regions of the materials being joined. The hardness profiles showed sudden changes of hardness what correlates with structure observations. In the vicinity of the weld nugget higher dislocation density was observed. Lowering the temperature of sheets and welding with intensive cooling caused a decrease in size of the weld nugget.Research limitations/implications: In the further studies, tensile and bending tests are planned. Moreover, an attempt of explaining the influence of precipitates at the regions boundaries on the fracture process.Practical implications: Good quality of the joints can be stated on the basis of structure analysis. The chosen parameters of welding can be considered as proper ones.Originality/value: Comparison of the welding of the alloys2017A and 6013 are not common. The results of studies and conclusions presented in the paper are consecutive data complementing knowledge on FSW of the aluminium alloys. The applied welding parameters ensure good quality of joints with respect to the technology.

  1. Parametric study of friction stir spot welding of aluminium alloy 5754

    OpenAIRE

    Klobc?ar, D.; Tus?ek, J.; Skumavc, A.; Smolej, A.

    2014-01-01

    The paper presents a parametric analysis of friction stir spot welding (FSSW) of aluminium alloy 5754 in a lap joint. Experimental plan was done according to the response surface methodology (RSM), where tool rotation speed varied between 988 and 3511 rpm, plunge rate between 24,4 and 150 mm/min and dwell time between 1 and 3,5s. The plunge depth was held constant at 0,4 mm. The welds were tensile-shear tested and the microstructure was analysed. Mathematical models describing the relationshi...

  2. Relations between sample preparation and SKPFM Volta potential maps on an EN AW-6005 aluminium alloy

    International Nuclear Information System (INIS)

    Quantitative measurements of the chemical composition and the local Volta potential contrast on metal surfaces can be performed with sub-micrometer resolution using a combination of scanning electron microscopy (SEM) and scanning kelvin probe force microscopy (SKPFM). Sample preparation techniques based on metal removal by mechanical and electrochemical polishing, OPS and ion-sputtering, may distort the local chemical composition or microstructure on the surface. Surfaces with insignificant mechanical and chemical distortions can be produced by ultramicrotomy. Ultramicrotomy gives quantitatively reliable SEM and SKPFM results when applied on extruded samples of an EN AW-6005 aluminium alloy

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

    Science.gov (United States)

    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.

  4. Investigation into the causes of cracking of 2024 aluminium alloy during rolling operation

    International Nuclear Information System (INIS)

    Aluminium alloy 2024 bars cracked during cold rolling to produce strips conforming to T-3 temper designation. The specimens had reduced to 10 mm X 10 mm size by hot rolling rectangular ingots of size 25 mm X 25 mm in 3 passes using the rolling mill. Microscopic studies of the cracked specimens revealed the presence of inclusions on the grain boundaries and in the fracture valleys. Energy dispersive X-ray analysis (EDAX) indicated that inclusions were rich in iron. Fractrogapy of fracture specimens were carried out using both optical scanning electron microscopy which indicated brittle fracture due to the presence of iron inclusions. (author)

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

    OpenAIRE

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

    2012-01-01

    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 electro...

  6. Strength evaluation of aluminium alloy bolt by nano-indentation hardness test

    International Nuclear Information System (INIS)

    A high strength aluminium alloy bolt (A7050, T7 temper treatment) has been developed by the authors. The bolt has a small grain size in the whole area of the bolt because of the large equivalent strain followed by thermo-mechanical treatment. As the bolt made of A7050 has a risk of stress corrosion cracking, to improve the stress corrosion cracking resistance, each grain should be strengthened inside. It has been confirmed that the nano-indentation at each grain inside increased with the increase of the equivalent strain by thermo-mechanical treatment processing (Authors)

  7. SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    N. FATCHURROHMAN

    2012-04-01

    Full Text Available In this research solidification characteristic of metal matrix composites consisted of titanium carbide particulate reinforced aluminium-11.8% silicon alloy matrix is performed. Vortex mixing and permanent casting method are used as the manufacturing method to produce the specimens. Temperature measurements during the casting process are captured and solidification graphs are plotted to represent the solidification characteristic. The results show, as volume fraction of particulate reinforcement is increased, solidification time is faster. Particulate reinforcement promotes rapid solidification which will support finer grain size of the casting specimen. Hardness test is performed and confirmed that hardness number increased as more particulate are added to the system.

  8. Measurement of spall strength of aluminium alloy, Al2024-T4

    International Nuclear Information System (INIS)

    In a shock wave experiment performed on the aluminium alloy, Al2024-T4, the sample is subjected to a peak shock pressure of 4.38 GPa by impacting it with a flyer accelerated to a velocity of 0.56 km/s in gas gun. The velocity of the flyer just before the impact and free surface velocity profile of the target during unloading is measured. Stress at Hugoniot elastic limit (?HEL), dynamic yield strength and spall strength determined from this profile are 0.70 GPa, 0.355 GPa and 1.43 GPa, respectively. (author)

  9. Fracture prediction during sawing of DC cast high strength aluminium alloy rolling slabs

    OpenAIRE

    Drezet, Jean-marie; Ludwig, Olivier; Jaquerod, Christophe; Waz, Emmanuel

    2007-01-01

    The semicontinuous direct chill (DC) casting of large cross-section rolling sheet ingots of high strength aluminium alloys (2xxx and 7xxx series) gives birth to high residual (internal) stresses generated by a non-uniform cooling. These stresses must be relieved by a thermal treatment in order to be able to safely saw both ingot butt and head. Otherwise, saw pinching or blocking might occur due to the compressive residual stresses, or cut parts might be brutally released by erratic propagatio...

  10. A vertical type twin roll caster for an aluminium alloy clad strip

    OpenAIRE

    Haga, T.; Nakamura, R.; Kuma, S.; Watari, H.

    2013-01-01

    Purpose: of this paper: Twin roll casters that can cast two layers and three layers clad strip of aluminium alloys were invented. One of the purposes of this paper is to report that the two layers and three layers clad strip could be cast by the twin roll caster of this study. The investigation of the characters of these casters and the clad strips was purpose of this paper, too. The connecting at the interface between the strips was most important in the casting of the clad strip. Therefore,...

  11. Parametric study of friction stir spot welding of aluminium alloy 5754

    Directory of Open Access Journals (Sweden)

    D. Klob?ar

    2014-01-01

    Full Text Available The paper presents a parametric analysis of friction stir spot welding (FSSW of aluminium alloy 5754 in a lap joint. Experimental plan was done according to the response surface methodology (RSM, where tool rotation speed varied between 988 and 3511 rpm, plunge rate between 24,4 and 150 mm/min and dwell time between 1 and 3,5s. The plunge depth was held constant at 0,4 mm. The welds were tensile-shear tested and the microstructure was analysed. Mathematical models describing the relationship between welding parameters and spot strength, axial force and rotational moment were developed and the optimal FSSW parameters were found.

  12. Friction Stir Processing of an AlSi6Cu4 cast aluminium alloy

    OpenAIRE

    St We?glowski, M.; Dymek, S.

    2011-01-01

    The present paper deals with the Friction Stir Processing (FSP) of an AlSi6Cu4 cast aluminium alloy. The emphasis was placed on thedetermination of an influence FSP parameters and the torque action on the tool. It was found that an increase in rotational speed of the tool causes a decrease in the torque. Simultaneously, the results showed that an increase in travelling speed of the tool brings about an increase in the torque. The metallographic examination of the processed surface layer of th...

  13. Effect of Welding Parameters on Metallurgical Properties of Friction Stir Welded Aluminium Alloy 6063-O

    OpenAIRE

    K. Balachandar; A. Varun Kumar

    2012-01-01

    The effect of process parameters on metallurgical properties of friction stir welded aluminium alloy 6063-O was analysed in the present study. Samples were friction stir welded under tool rotational speed of 600, 800 and 1200 rpm and traversing speed of 0.6, 0.9 and 1.2 mm sec-1, with an axial load of 8000 kg constant for all trials and the process parameters were optimized by using Taguchi orthogonal array. Optical microstructure analysis were carried out to define the metallurgical properti...

  14. CFD modelling of DC casting of aluminium alloys

    International Nuclear Information System (INIS)

    Casting and solidification of metals is a process in which transport phenomena as heat flow, mass flow and fluid flow are highly coupled. The major drive for casting modelling is to improve the insight how process parameters affect casting performance and a major part of current solidification modelling applications is used for the prevention of casting defects. Solidification modelling activities are dope at nearly all the size scales for the physical processes involved: nucleation, dendrite tip growth, liquid metal flow through a mushy semi-solid dendritic network, etc.. In this paper we will concentrate on the coupled fluid flow effects during DC casting. Compositional differences over the whole cross-section of an ingot, defined as macrosegregation, can have a significant impact on the properties of the finished product, in particular for strong alloy applications. There are several hypotheses possible to explain macrosegregation, although they all have in common the attributed effect of fluid flow. A reliable calculation of macrosegregation during the casting of alloys depends on the accurate modelling of the associated physical mechanisms. Besides that the particular microsegregation model (Scheil, lever-rule) is of importance, the relative movement of the liquid and solid phase inside the mushy zone controls the amount of macrosegregation. In solving the solute concentration equation, the accuracy of the velocity field is thus of great concern. From the literatis thus of great concern. From the literature on computational fluid dynamics, we also know that in high Peclet number flows, the incorrect treatment of the convection terms causes numerical diffusion, which can completely overshadow the actual physical diffusion. Throughout the history of CFD, a great number of differencing schemes for the convection term have been proposed in order to reduce the numerical diffusion. In the current research several of these schemes are examined on their ability to correctly predict macrosegregation in the DC casting of an Al-4.5 wt% Cu alloy. The occurrence of oxides in the form of films and inclusions can give major problems during aluminum casting and processing. Inclusions and films move together with the main flow in the metal distribution system and can cause problems when trapped in the solidifying aluminum. The level of oxides and inclusions in standard DC casting practices is controlled with the use of in-line filter boxes and degassing units. However, during the transfer from these metal treatment systems to the casting station pick up of inclusions and oxides can occur. In our simulations we try to assess quantitatively some of the upstream fluid flow effects in relation to the filling behavior of the DC mould cavity and the number of inclusions trapped in the launder system. Placing baffles in the launder therefore modifies the fluid flow. The location of these baffles is an important parameter in modifying the fluid flow behavior. Both the controlled filling of the mould as well as entrapment of inclusions can be achieved. Results of numerical simulations of fluid flow with discrete particles of different mass and distribution are given. The results show that relatively subtle changes in the flow control can change the flow of inclusions drastically. Refs. 2 (author)

  15. Tribological Potential of Hybrid Composites Based on Zinc and Aluminium Alloys Reinforced with SiC and Graphite Particles

    Directory of Open Access Journals (Sweden)

    D. Džuni?

    2012-12-01

    Full Text Available The paper reviews contemporary research in the area of hybrid composites based on zinc and aluminium alloys reinforced with SiC and graphite particles. Metal matrix composites (MMCs based on ZA matrix are being increasingly applied as light-weight and wear resistant materials. Aluminium matrix composites with multiple reinforcements (hybrid AMCsare finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. The results of research show that the hybrid composites possess higher hardness, higher tensile strength, better wear resistance and lower coefficient of friction when compared to pure alloys.

  16. PRESSURE DURING CURING AND THE STRENGTH OF 2024, 2017A AND 1050 ALUMINIUM ALLOY SHEET ADHESIVE JOINTS

    Directory of Open Access Journals (Sweden)

    Anna Rudawska

    2015-05-01

    Full Text Available This paper is primarily devoted to one of adhesive curing process parameters – pressure applied during curing, as well as the type of adhesive. The aim of this work is to determine the influence of pressure applied during curing process of aluminium alloy sheet adhesive joints on the strength of adhesive joints formed with two epoxy adhesives: Loctite 9484 and Loctite 9466. Three types of aluminium alloy sheets were tested, namely AW 2024, AW 2017A and AW 1050, applied in many branches of engineering. During formation of adhesive joints, other conditions remained unchanged, and surface preparation operations included mechanical processing and degreasing.

  17. The effect of the volume fraction on precipitate coarsening in nickel-base superalloys and aluminium-lithium alloys

    International Nuclear Information System (INIS)

    Coarsening of ?'-precipitates in nickel-base superalloys and of ?'-precipitates in aluminium-rich aluminium-lithium alloys is investigated by analytical transmission electron microscopy. The growth rate of the particles increases with their volume fraction. This increase is described best by Ardell's model. The ?'-volume fractions of the superalloys are independent of the annealing time t. In the case of the Al-Li alloys the analogous statement holds only if t is long enough to yield average ?'-particle radii of 9.4 nm or more. For shorter heat-treatments the ?'-volume fraction increases strongly with t. (orig.)

  18. Supersonic laser spray of aluminium alloy on a ceramic substrate

    International Nuclear Information System (INIS)

    Applying a ceramic coating onto a metallic substrate to improve its wear resistance or corrosion resistance has attracted the interest of many researchers during decades. However, only few works explore the possibility to apply a metallic layer onto a ceramic material. This work presents a novel technique to coat ceramic materials with metals: the supersonic laser spraying. In this technique a laser beam is focused on the surface of the precursor metal in such a way that the metal is transformed to the liquid state in the beam-metal interaction zone. A supersonic jet expels the molten material and propels it to the surface of the ceramic substrate. In this study, we present the preliminary results obtained using the supersonic laser spray to coat a commercial cordierite ceramic plate with an Al-Cu alloy using a 3.5 kW CO2 laser and a supersonic jet of Argon. Coatings were characterized by scanning electron microscopy (SEM) and interferometric profilometry

  19. The role of strontium in modifying aluminium–silicon alloys

    International Nuclear Information System (INIS)

    Small amounts of strontium can transform the morphology of the eutectic silicon phase present in Al–Si casting alloys from coarse plate-like to fine fibrous networks. In order to understand this industrially important but hitherto insufficiently understood effect, the strontium distribution was studied in atomic resolution by atom probe tomography and in nanometre resolution by transmission electron microscopy. The combined investigations indicate that Sr co-segregates with Al and Si within the eutectic Si phase. Two types of segregations were found: (i) nanometre-thin rod-like co-segregations of type I are responsible for the formation of multiple twins in a Si crystal and enable its growth in different crystallographic directions; (ii) type II segregations come as more extended structures, restrict growth of a Si crystal and control its branching. We show how Sr enables both kinds of mechanisms previously postulated in the literature, namely “impurity-induced twinning” (via type I) and growth restriction of eutectic Si phase (via type II).

  20. The inhibition effect of mad Honey on corrosion of 2007-type aluminium alloy in 3.5% NaCl solution

    Scientific Electronic Library Online (English)

    Husnu, Gerengi; Haydar, Goksu; Pawel, Slepski.

    2014-02-01

    Full Text Available The inhibition effect of mad honey on corrosion of 2007-type aluminium alloy in 3.5% NaCl solution was investigated by Tafel extrapolarisation (TP), electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). All the studied parameters exhibited good anti- [...] corrosive properties against corrosion of 2007-type aluminium alloy in the test solution; the corrosion rates decreased with the increase of the mad honey concentration. The surface morphology of the alloy was examined under scanning electron microscopy (SEM) in the absence and presence of the inhibitor. The inhibitory adsorption processes of mad honey on the 2007-type aluminium alloy surfaces conformed to the Langmuir adsorption isotherm.

  1. Studies on Age Hardening for Improvement of 6261 and 6060 Extruded Aluminium Alloys

    Science.gov (United States)

    Au, Ka Ki (Katie); Hodgson, Michael; Pasang, Timotius; Chiu, Yu Lung

    The magnesium silicide precipitates in the 6XXX series alloy are the main components contributing to the heat treatable properties and T6 strength of the alloy, which is influenced by the size, morphology and distribution of this phase. During the extrusion process, the strength contributing phase, magnesium silicide is supposed to dissolve and form again in a controlled state during age hardening. Whereas the intermetallic AlFeSi phase has little if any influence on the strength, the ? phase of this intermetallic is known to cause brittle fracture of this alloy, as opposed to the less detrimental, more equiaxed ? phase formed during homogenisation. This study investigates the as-extruded 6060 and the more heavily alloyed 6261 aluminium alloys, as well as the subsequent heat treated forms to investigate the ageing conditions to optimise hardening and shorten age hardening times for higher cost effectiveness. The microstructure, texture and precipitate size and distributions were studied using optical microscopy, SEM, EBSD and DSC. SEM and EDAX results have indicated signs of evenly distributed ? AlFeSi and ? Magnesium Silicide precipitates. The phase responsible for hardening is believed to be the much smaller scaled ?" magnesium silicide, requiring much higher resolution studies.

  2. Microstructural aspects and mechanical properties of friction stir welded AA2024-T3 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Highlights: ? FSW is an attractive process for joining Al alloys. ? This solid state process results in a joint free of defects. ? Tensile strength values close to the base metal strength can be reached. ? Fatigue performance is better, when comparing to riveted joints. -- Abstract: In the present work, aluminium alloy AA2024-T3 thin sheets were joined by the Friction Stir Welding - FSW - process. Butt joints were obtained in 1.6 mm sheets, using an advancing speed of 700 mm/min. These joints were characterised by optical, scanning electron microscopy, tensile and fatigue mechanical tests. The results showed that the resulting microstructure is free of defects and the tensile strength of the welded joints is up to 98% of the base-metal strength. Fatigue tests result indicates an equivalent stress intensity factor (kt) of approximately 2.0 for the welded samples. Consequently, the FSW process can be advantageous compared to conventional riveting for airframe applications.

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

    International Nuclear Information System (INIS)

    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.

  4. Effect of Ultrasonic Treatment on the Microstructure of A201 Aluminium Alloy for Thixoforming

    International Nuclear Information System (INIS)

    It is known that the introduction of high intensity ultrasonic waves into liquid and solidifying metals leads to a non-dendritic and fine grain structure which is the requirement for semi-solid feedstock production. The effect of vibration time on the semi-solid microstructure of the A201 aluminium alloy billets fabricated with the ultrasonic treatment in the liquid state was studied in this paper. It was observed that the application of ultrasound technology can break up and distribute the dendrites which are present in the as-cast alloy. A suitable thixotropic microstructure with relatively rounded and fine globules could be obtained by ultrasonically treating liquid metal at 690 deg. C for a treatment time of 1 minute, cooling to room temperature and then reheating to the semi-solid state. This shows the ultrasonic treatment could be an economic and alternative route to produce A201 semi-solid feedstock for thixoforming.

  5. Effect of Ultrasonic Treatment on the Microstructure of A201 Aluminium Alloy for Thixoforming

    Science.gov (United States)

    Kandemir, Sinan; Atkinson, Helen V.; Lawes, Simon D. A.

    2011-05-01

    It is known that the introduction of high intensity ultrasonic waves into liquid and solidifying metals leads to a non-dendritic and fine grain structure which is the requirement for semi-solid feedstock production. The effect of vibration time on the semi-solid microstructure of the A201 aluminium alloy billets fabricated with the ultrasonic treatment in the liquid state was studied in this paper. It was observed that the application of ultrasound technology can break up and distribute the dendrites which are present in the as-cast alloy. A suitable thixotropic microstructure with relatively rounded and fine globules could be obtained by ultrasonically treating liquid metal at 690 °C for a treatment time of 1 minute, cooling to room temperature and then reheating to the semi-solid state. This shows the ultrasonic treatment could be an economic and alternative route to produce A201 semi-solid feedstock for thixoforming.

  6. Crystallization of alloys on aluminium base in a near-zero gravity state

    International Nuclear Information System (INIS)

    Crystallization of aluminium alloy systems (Al-W, Al-Sb and Al-Cu) in a near-zero gravite state, realized on the orbital scientific complex ''Salyut-6'' and ''Soyuz'', is studied; the effect of reduced gravitation on crystallization is established. It is shown that the absence of free convection in melts, observed in cosmic experiments, leads to decrease of crystal nucleation intensity and favours melt overcooling during crystallization to an even greater degree than on the Earth. The crystallization texture of Al-matrix of Al+5%Cu and Al+18%Sb alloys in the temperature gradient direction is different after cosmic experiments and the one, carried out on the Earth

  7. Microstructure evolution in a 2618 aluminium alloy during creep-fatigue tests

    Energy Technology Data Exchange (ETDEWEB)

    Novy, Frantisek; Hadzima, Branislav [Zilina Univ. (Slovakia). Dept. of Materials Engineering; Janecek, Milos; Kral, Robert [Charles Univ., Prague (Czech Republic). Dept. of Physics of Materials

    2012-06-15

    Microstructure changes in the 2 618 aluminium alloy during creep-fatigue tests were studied. These tests simulate the conditions of the application of this alloy in devices for the exhaustion of hot gasses generated during fire in closed or difficultly accessible areas. Creep-fatigue tests result in high dislocation density in subgrains and narrow subgrain boundaries, in contrast to creep tests reported in our previous work where large subgrains were observed with relatively wide subgrain boundaries and relatively low dislocation density in grains. Extensive precipitation occurred with denuded (precipitate-free) zones along grain boundaries. The coherent S-phase (Al{sub 2}CuMg) transformed into partially coherent needle-shaped S' precipitates. Superior stress amplitude caused reduced lifetime and wider denuded zones. A model of the formation of denuded zones along (sub)-grain boundaries was proposed. (orig.)

  8. Comparison of corrosion behaviour of friction stir processed and laser melted AA 2219 aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: ? Poor corrosion resistance of AA 2219 can be improved by surface treatments. ? FSP and LM leads to dissolution of second phase particles. ? No literature available on comparison of corrosion behaviour after FSP and LM. ? The study implies FSP is as good as LM in improving the corrosion resistance of AA 2219. -- Abstract: Dissolution of second phase particles (CuAl2) present in AA 2219 aluminium improves the corrosion resistance of the alloy. Two surface treatment techniques, viz., solid state friction stir processing and fusion based laser melting lead to the reduction in CuAl2 content and the effect of these processes on the corrosion behaviour of the alloy is compared in this study. Potentiodynamic polarization and electrochemical impedance spectroscopy tests were carried out to compare corrosion behaviour. The corrosion resistance achieved by friction stir processing is comparable to that obtained by the laser melting technique.

  9. Corrosion protection of Mg/Al alloys by thermal sprayed aluminium coatings

    International Nuclear Information System (INIS)

    The protective features of thermal sprayed Al-coatings applied on AZ31, AZ80 and AZ91D magnesium/aluminium alloys were evaluated in 3.5 wt.% NaCl solution by electrochemical and gravimetric measurements. The changes in the morphology and corrosion behaviour of the Al-coatings induced by a cold-pressing post-treatment were also examined. The specimens were characterized by scanning electron microscopy, energy dispersive X-ray analysis and low-angle X-ray diffraction. The as-sprayed Al-coatings revealed a high degree of porosity and poor corrosion protection, which resulted in galvanic acceleration of the corrosion of the magnesium substrates. The application of a cold-pressing post-treatment produced more compact Al-coatings with better bonding at the substrate/coating interface and higher corrosion resistance regardless of the nature of the magnesium alloy.

  10. Triazole and thiazole derivatives as corrosion inhibitors for AA2024 aluminium alloy

    International Nuclear Information System (INIS)

    The 1,2,4-triazole, 3-amino-1,2,4-triazole, benzotriazole and 2-mercaptobenzothiazole were evaluated in the present work as corrosion inhibitors for protection of the 2024 aluminium alloy in neutral chloride solutions. The corrosion protection performance was investigated by means of DC polarization and electrochemical impedance spectroscopy (EIS). Scanning Kelvin probe force microscopy (SKPFM) and atomic force microscopy (AFM) were used to study the evolution of the Volta potential distribution and the surface topography during corrosion tests. The results show that all inhibitors under study confer corrosion protection to the AA2024 alloy forming a thin organic layer on the substrate surface. Benzotriazole and 2-mercaptobenzothiazole offer better corrosion protection in comparison with the other two. The inhibitors studied act decreasing the rate of both the anodic and cathodic processes. In the latter case the dealloying of the copper-reach particles is hindered, slowing down the oxygen reduction

  11. TIG and MIG welding of 6061 and 7020 aluminium alloys. Microstructural studies and mechanical properties

    International Nuclear Information System (INIS)

    The aluminium alloys of the 6XXX and 7XXX series, are actually considered of medium and high strength, and are been profusely used in different industries such as aeronautical, automotive, etc.However, its wide application as structural material needs of the proper development of their joining process. The present work describes the results obtained from the microstructural evaluation, both with optical and scanning electronic micros copies (OM) and SEM), and of the mechanical one (hardness changes) of the weld produced in the alloys using different arc welding techniques: FTAW (TIG) and GMAW (MIG). For the last one, a filler metal with a composition of Al-5Mg, AWS denomination A5.10-92 (AA5356), has been used. (Author) 5 refs

  12. Galvanic corrosion of rare earth modified AM50 and AZ91D magnesium alloys coupled to steel and aluminium alloys

    Directory of Open Access Journals (Sweden)

    Mohedano, Marta

    2014-03-01

    Full Text Available Electrochemical and gravimetric measurements were used to examine the effects of neodymium and gadolinium additions on the galvanic corrosion behaviour of AM50 and AZ91D magnesium alloys coupled to A 570 Gr 36 carbon steel and AA2011-AA6082 aluminium alloys. Rare earth modified alloys showed Al2Nd/Al2Gd and Al-Mn-Nd/Al-Mn-Gd intermetallics, reduced area fraction of ?-Mg17Al12 phase and increased corrosion resistance due to increased surface passivity and suppression of micro-galvanic couples. Neodymium and gadolinium additions improved the galvanic corrosion resistance of AM50 alloy, but were less effective in case of the AZ91D alloy. The AA6082 alloy was the most compatible material and the AA2011 alloy was the least compatible.Se emplearon medidas electroquímicas y gravimétricas para examinar el efecto de la adición de neodimio y gadolinio en el comportamiento a la corrosión galvánica de las aleaciones AM50 y AZ91D en contacto con acero al carbono A 570 Gr 36 y aleaciones de aluminio AA2011 y AA6082. Las aleaciones modificadas con tierras raras mostraron intermetálicos Al2Nd/Al2Gd y Al-Mn-Nd/Al-Mn-Gd, menor fracción de fase ?-Mg17Al12 y un incremento de la resistencia a la corrosión debido al aumento de la pasividad de la superficie y a la eliminación de micro pares galvánicos. Las adiciones de neodimio y gadolinio mejoraron la resistencia a la corrosión galvánica de la aleación AM50, pero fueron menos efectivas en el caso de la aleación AZ91D. La aleación AA6082 fue el material más compatible y la aleación AA2011 el menos compatible.

  13. Effect of the temperature and the chlorine pressure, over the aluminium chlorides obtained by direct chlorination of the 6061 alloy

    International Nuclear Information System (INIS)

    The aluminium chloride is synthesized by direct chlorination of aluminium, in agreement with the following reaction: Al(s) + 3/2 Cl2 AlCl3 (s,g).The present work focuses on the preparation of aluminium chlorides by two methods: (a) Chlorination of 6061 aluminium alloy with gaseous chlorine in sealed containers, filled with different pressures of gas, from 0.8 to 74 Kpa and in the range of temperature between 2000 and 5000C.(b) Chlorination of the same alloy in chlorine flow between 1500 and 4000C.In the sealed systems, the hexahydrated aluminium trichloride predominated over the anhydrous form. For pressures lower than 14 Kpa and temperatures under 2500C, the chloride didn't appear.The residues were rich in aluminium, chlorine and magnesium.In the other systems, the anhydrous chloride was found in the areas of the reactor of temperatures above 1000C, for all the thermal treatments. The waste was composed by CrCl3 and AlCl3.6H2O.The influence of the chlorine pressures and the heating temperature over the characteristics of the product, was studied.The characterization techniques were x-ray diffraction and energy dispersive spectroscopy, and the evolution of the structure was followed by scanning electron microscopy

  14. Corrosion protection of aluminium alloy by cerium conversion and conducting polymer duplex coatings

    International Nuclear Information System (INIS)

    Highlights: ? Cerium conversion coating must be preceded by alkaline surface treatment. ? Cerium conversion coating promotes the anchoring of the PAni conducting polymer. ? PAni coating presents active corrosion protection associated with a barrier effect. ? Duplex coatings show superior corrosion protection than each coating alone. ? A scheme representing the treatment stages for the duplex coating is shown. - Abstract: The corrosion protection of AA6063 aluminium alloy by cerium conversion, polyaniline conducting polymer and by duplex coatings has been investigated. The electrochemical behaviour was evaluated in aerated 3.5 wt.% NaCl. All coatings tested shifted the corrosion and pitting potentials to more positive values, indicating protection against corrosion. The duplex coatings are significantly more effective than each coating alone: corrosion and pitting potentials were shifted by +183 and +417 mV(SCE), respectively, by duplex coatings in relation to the untreated aluminium alloy. Optical microscopy and scanning electron microscopy are in agreement with the electrochemical results, reinforcing the superior performance of duplex coatings.

  15. Investigating the Acid Failure of Aluminium Alloy in 2 M Hydrochloric Acid Using Vernonia amygdalina

    Directory of Open Access Journals (Sweden)

    Olugbenga A. Omotosho

    2012-04-01

    Full Text Available The acid failure of aluminium alloy in 2 M hydrochloric acid solution in the presence of Vernonia amygdalina extract was investigated using gasometric technique. Aluminium alloy coupons of dimension 4 cm by 1 cm were immersed in test solutions of free acid and also those containing extract volumes of 2, 3, 4 and 5 cm3 at ambient temperature for 30 minutes. The volumes of hydrogen gas evolved as a result of the rate of reaction were recorded and analyzed. Analysis revealed that maximum inhibitor efficiency which corresponds to the lowest corrosion rate was obtained at optimum inhibitor volumes of 5 cm3, with reduction in the corrosion rate observed to follow in order of increasing extract volumes. Adsorption study revealed that Temkin isotherm best described the metal surface interaction with the extract phytochemicals, with 12 minutes becoming the best exposure time for the phytochemicals to adsorb to the metal surface at all volumes. Statistical modelling of the corrosion rate yielded an important relationship suitable for estimating corrosion rate values once volumes of the extract is known. Microstructural studies, showed an indirect relationship between crack growth rates and extract volumes, while consistency of the irregular intermetallic phases increases with increasing extract volumes.

  16. Different Cold Spray Deposition Strategies: Single- and Multi-layers to Repair Aluminium Alloy Components

    Science.gov (United States)

    Rech, Silvano; Trentin, Andrea; Vezzù, Simone; Vedelago, Enrico; Legoux, Jean-Gabriel; Irissou, Eric

    2014-12-01

    Cold spraying is increasingly being used for reconstruction or repair of damaged aluminium alloy components, especially in the aviation industry. Both thin (coatings are necessary to achieve dimensional recovery of such components. Thin and above all thick coatings can be deposited in a single pass (single layer) or in several passes (multi-pass), resulting in different thermal and stress effects in the component and the coating itself. The thermal input, the amount and type of residual stresses and the porosity affect various characteristics such as adhesion, crack propagation and mechanical properties of the coating. In this study, two sets (single- and multi-pass) of aluminium alloy (AA6061) coatings with different thicknesses (0.5 mm to 2 mm) were deposited onto AA6061 substrates and compared using metallographic and fractographic analyses, four-point bending testing, residual stress analysis and Vickers microhardness indentation. Finally, the coating adhesion and cohesion were measured using the standard ASTM-C633 adhesion test and tubular coating tensile test. This study demonstrates that the single-layer strategy results in greater adhesion and lower porosity, while multilayer coatings have higher elastic modulus. Independent of the strategy, the compressive residual stress decreases as a function of coating thickness.

  17. Optimisation of the rivet joints of the CFRP composite material and aluminium alloy

    Directory of Open Access Journals (Sweden)

    A. Czulak

    2007-01-01

    Full Text Available Purpose: The project included analysis of strain, cracking, and failure of riveted joints of plate elements madefrom the carbon-fibre-reinforced plastics (CFRP and from the 6061 aluminium alloy.Design/methodology/approach: The modelled static tensile strength test carried out for the plates from CFRPand from the 6061 aluminium alloy joined with the steel rivet. Computer simulation was carried out with IDEASsoftware package employing the FEM.Findings: Simulations using the mesh with a bigger number of FEM elements do not yield better accuracy ofcalculations and do not improve convergence with the results of laboratory experiments. Only the calculationtime gets longer. Computer simulation has also show that the type of contacts employed between elementsaffects the results significantly.Research limitations/implications: For the composite materials, joints between materials and computersimulation examinations are planed.Practical implications: Results obtained for the mesh with 4 and 5 FEM elements are the closest to the resultsof laboratory experiments, which is confirmed by the strain plot. Simulations using the mesh with a biggernumber of FEM elements do not yield better accuracy of calculations and do not improve convergence with theresults of laboratory experiments. Only the calculation time gets longer. Computer simulation has show that thetype of contacts employed between elements affects the results significantly.Originality/value: The paper presents influence of fibre mesh closeness on convergence of the results with laboratorytests. Simulation results were collected and compared with the laboratory static tensile strength tests results.

  18. New iron-aluminium alloy with thermally stable coherent intermetallic nanoprecipitates for enhanced high-temperature creep strength

    International Nuclear Information System (INIS)

    Poor ductility and strength at high temperatures, especially under slow strain rate or creep conditions, have prevented the use of iron-aluminium alloys or aluminide intermetallics, despite decades of intensive research. The low strength at high temperature is due to the inability of hardening particles such as carbides to resist dissolution or coarsening at these temperatures. A new iron-aluminium alloy with zirconium and chromium additions has been discovered that forms fine coherent precipitates on annealing cast material that remain very fine even after extended annealing at temperatures as high as 900 deg. C. These precipitates have a complex Fe3Zr structure and form in a cube-on-cube orientation relationship in the body-centred cubic matrix. The excellent stability of these intermetallic precipitates, due to low solute solubility and diffusivity in the iron-aluminium matrix, and the low energy, near-coherent interface, allows important improvements in high-temperature creep stresses

  19. Experimental and numerical analysis of in- and out- of plane constraint effects on fracture parameters: Aluminium alloy 2024.

    Czech Academy of Sciences Publication Activity Database

    Seitl, Stanislav; Huta?, Pavel; García, T.; Canteli, A.

    7 2013, ?. 7 (2013), s. 53-64. ISSN 1802-680X Grant ostatní: Interní podpora AV ?R(CZ) M100411204 Keywords : LELM * stress intensity tensor * constraint * aluminium alloy * plane strain * plane stress Subject RIV: JL - Materials Fatigue, Friction Mechanics

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

    Science.gov (United States)

    Leszczy?ska-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. PMID:20500405

  1. Wear Behaviour of Zinc-Aluminium Alloys and the Bearings Produced from these Alloys

    OpenAIRE

    Savas?kan, Temel; Pu?rc?ek, Genc?ag?a

    2000-01-01

    In this study, two ternary zinc-aluminum-copper and two quaternary zinc-aluminum-copper-silicon alloys were produced by permanent mould casting. The wear behaviour of these alloys were investigated with a pin-on-disc machine The wear behaviour of the journal bearings produced from these alloys was investigated with a bearing test rig. The wear resistance of zinc-aluminum based alloys was found to be higher than that of CuSn12 bronze. ?n addition, the bearings produced from the zinc...

  2. Investigation of the effects of Magnesium Content and Cooling Rate on the Mechanical Properties of Aluminium-Magnesium Alloys Refined with Titanium-Boride Master Alloy

    OpenAIRE

    Fatai Olufemi ARAMIDE; Samuel Ademola IBITOYE; Obafunmilola Oluwatosin FAGADE

    2012-01-01

    Investigations into the effects of magnesium content and cooling rates on the mechanical properties of aluminium-magnesium alloys refined with titanium-boride master alloy was conducted. Experimental samples were produced from melt with Mg content ranging from 0% to 8%, poured and cooled in air, water and oil. Standard sample dimensions were produced for tensile and hardness tests. It was observed that both the Mg content and the cooling rate affect the mechanical properties; elongation (duct...

  3. A silanol-based nanocomposite coating for protection of AA-2024 aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: · A new silanol-based hybrid coating has been synthesized. · The incorporation of CeO2 and ZrO2 nanoparticles into the coating greatly improves the corrosion resistance of the coated aluminium alloy. · The effectiveness of the coating is increasingly evident for long term exposure to the sodium chloride solution. · The silanol-based nanocomposite coatings have self-healing ability. - Abstract: A new hybrid sol-gel type film, composed of tetraethylorthosilicate (TEOS) and tetraocthylorthosilicate (TEOCS), and modified with different nanoparticle systems, has been investigated as a coating for protection of AA-2024-T3 aluminium alloy. The nanoparticle systems considered were either ZrO2 or CeO2 or their combination. The zirconia nanoparticles were prepared from a Zr (IV) propoxide sol (TPOZ), using an organic stabilizer, and the CeO2 nanoparticles were developed spontaneously after adding cerium nitrate solution to the hybrid sol. The chemical composition and the structure of the hybrid sol-gel films were examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion resistance of the coated AA-2024 alloy was examined by potentiodynamic polarization. The results revealed that, for short exposure times in the electrolyte, incorporation of ZrO2 or CeO2 nanoparticles in the hybrid film does not provicles in the hybrid film does not provide an increase in the corrosion resistance of the coated AA-2024 alloy. Further, the resistance was significantly reduced by increasing the nanoparticle content. Conversely, by incorporating both nanoparticles (ZrO2 and CeO2), the corrosion resistance of the resulting hybrid films increased slightly. The behavior changed significantly when the coated alloy was exposed to the electrolyte for 5 days. The corrosion resistance of the coatings, unmodified and modified with CeO2 or ZrO2 nanoparticles, decreased by two or three orders of magnitude, while the film modified with both nanoparticles (CrO2 and ZrO2) showed a relatively high corrosion resistance and responsiveness to activation processes during anodic polarization.

  4. A silanol-based nanocomposite coating for protection of AA-2024 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.; Pavez, J.; Azocar, I.; Zagal, J.H. [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Zhou, X. [Corrosion and Protection Centre, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Melo, F. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Santiago (Chile); Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Paez, M.A., E-mail: maritza.paez@usach.cl [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile)

    2011-09-01

    Highlights: {center_dot} A new silanol-based hybrid coating has been synthesized. {center_dot} The incorporation of CeO{sub 2} and ZrO{sub 2} nanoparticles into the coating greatly improves the corrosion resistance of the coated aluminium alloy. {center_dot} The effectiveness of the coating is increasingly evident for long term exposure to the sodium chloride solution. {center_dot} The silanol-based nanocomposite coatings have self-healing ability. - Abstract: A new hybrid sol-gel type film, composed of tetraethylorthosilicate (TEOS) and tetraocthylorthosilicate (TEOCS), and modified with different nanoparticle systems, has been investigated as a coating for protection of AA-2024-T3 aluminium alloy. The nanoparticle systems considered were either ZrO{sub 2} or CeO{sub 2} or their combination{sub .} The zirconia nanoparticles were prepared from a Zr (IV) propoxide sol (TPOZ), using an organic stabilizer, and the CeO{sub 2} nanoparticles were developed spontaneously after adding cerium nitrate solution to the hybrid sol. The chemical composition and the structure of the hybrid sol-gel films were examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion resistance of the coated AA-2024 alloy was examined by potentiodynamic polarization. The results revealed that, for short exposure times in the electrolyte, incorporation of ZrO{sub 2} or CeO{sub 2} nanoparticles in the hybrid film does not provide an increase in the corrosion resistance of the coated AA-2024 alloy. Further, the resistance was significantly reduced by increasing the nanoparticle content. Conversely, by incorporating both nanoparticles (ZrO{sub 2} and CeO{sub 2}), the corrosion resistance of the resulting hybrid films increased slightly. The behavior changed significantly when the coated alloy was exposed to the electrolyte for 5 days. The corrosion resistance of the coatings, unmodified and modified with CeO{sub 2} or ZrO{sub 2} nanoparticles, decreased by two or three orders of magnitude, while the film modified with both nanoparticles (CrO{sub 2} and ZrO{sub 2}) showed a relatively high corrosion resistance and responsiveness to activation processes during anodic polarization.

  5. Selected properties of the aluminium alloy base composites reinforced with intermetallic particles

    Directory of Open Access Journals (Sweden)

    M. Adamiak

    2005-12-01

    Full Text Available Purpose: The main aim of this work is to investigate two types of intermetallics TiAl and Ti3Al as reinforcement and their influence on selected properties and microstructure of aluminium matrix composites.Design/methodology/approach: Aluminium matrix composites were produced employing the atomised aluminium alloy AA6061 as metal matrix, when as reinforcement TiAl and Ti3Al intermetallics particles were used. The powders were cold pressed and then hot extruded. To evaluate the effect of mechanical milling two types of ball mills were used: a low energy (horizontal ball mill and a high energy one (eccentric ball mill. Reinforcement contents for both processes 5, 10, 15 % by weight. To determine hardness Vickers tests were performed. Microstructure observations were made by optical microscopy and scanning electron microscopy SEM.Findings: Based on the examinations carried out one can state that the mechanical milling can produce composites powders with homogenous distribution of reinforcement particles. The mechanically milled and extruded composites show finer and better distribution of reinforcement particles what leads to better mechanical properties of obtained products.Research limitations/implications: In order to evaluate with more detail the possibility of applying these composite materials at practical application, further investigations should be concentrated on the interface reaction of the matrix and reinforcing particles during elevated temperature exposition and their influence on mechanical properties.Practical implications: The composites materials produced by this way have shown significant improvement of the mechanical properties in comparision with matrix materials. Good properties of the composites make them suitable for various technical and industrial applications.Originality/value: It should be stressed that the materials as intermetallic compounds with outstanding mechanical properties and good thermal stability were developed making them a powerful material to be used in this kind of composites as the alternative for the reinforcements usually investigated and utilized to the composites materials production - alumina or silicon carbide.

  6. The influence of artificial ageing on the corrosion behaviour of a 2050 aluminium–copper–lithium alloy

    International Nuclear Information System (INIS)

    Highlights: •The corrosion behaviour of the 2050 Al–Cu–Li alloy was studied. •Its corrosion behaviour was linked to the distribution of T1 precipitates. •The copper content in solid solution also influenced its corrosion behaviour. •In the T34 metallurgical state, the alloy was susceptible to intergranular corrosion. •During ageing at 155 °C, the alloy became susceptible to intragranular corrosion. -- Abstract: The influence of artificial ageing on the corrosion behaviour of the recently developed 2050 Al–Cu–Li aluminium alloy in chloride-containing solutions was studied. Corrosion tests showed that artificial ageing changed the corrosion morphology of the alloy from intergranular to intragranular and decreased the corrosion potential of the alloy. Transmission electron microscopy observations combined with small-angle X-ray scattering measurements were used to establish a link between the distribution of T1 precipitates and the corrosion behaviour

  7. Surface modification of aluminium - lithium alloy using prenitriding option and SixNy coating deposition

    Directory of Open Access Journals (Sweden)

    ?. Kaczmarek

    2009-12-01

    Full Text Available Purpose: EU directive of CO2 emission reduction causes many applied technologies to become unprofitable considering environmental protection. Due to that, there is an urgent need to create new or modify existing technological solutions - especially in the field of materials engineering. One of the options to reduce CO2 emission is replacement of parts made of steel by Aluminum -Lithium alloys mainly in such branches like automotive and aircraft industry.Design/methodology/approach: Prenitriding option was carried out in low pressure plasma discharge mode, at a substrate temperature below 200ºC followed by the deposition of 500 nm thick SixNy coating. Morphology and mechanical properties were compared with substrate without prenitriding treatment.Findings: In this paper, first promising results of surface treatment with the use of prenitriding option of Al-Li alloy are presented. The results showed that the wear resistance of the Al-Li alloy may be modified by application of plasma enhanced CVD [1-4]. Two different types of surface modification were applied.Research limitations/implications: In case of vehicles’ parts, subjected to wear or/and contact fatigue a use of light weight alloys gives rise to many difficulties, caused by their low surface parameters. The aluminium alloys applied for elements operated in wear contact even with the best possible mechanical properties at the moment, it is limited due to still not enough tribological properties. The research in this field may bring another reduction of vehicles total weight.Practical implications: At present, ultra light materials with high durability are elaborated for components,e.g. in automotive industry mainly to realize a light gearbox.Originality/value: Functional Gradient Coatings (FGC was deposited below temperature which could cause destruction of “tailored” structure of the substrate.

  8. Aluminium alloy selection for use as structural material in research reactors

    International Nuclear Information System (INIS)

    Information on a range of aluminium alloys commonly used in the construction of research, experimental or production reactors (series 5XXX and 6XXX)) has been reviewed to assess their capability to sustain a full 40 years life period of use as RPV, reflector tank or other core component material, taking into account their corrosion resistance, fracture properties and irradiation damage. The corrosion behaviour of the studied alloys is acceptable when used in nuclear grade water; they do not suffer of pitting corrosion, crevice corrosion or stress corrosion cracking (SCC). However, in certain conditions they may be susceptible to intergranular corrosion. Based on the available published information, it could be concluded that the alloy 6061-T6 would be the most suitable material to be employed in research reactor conditions (maximum working temperature 120 o C, normal radiation level, water flow, etc.) and sustain 40 years of service if a correct water control is assured. For working temperatures around 60 o C, 6061/T6 alloy would undergo a moderate irradiation hardening degree and show good ductility retention for over 40 years. In case of short temperature excursions, this material will not suffer of any significant overaging. However, this parameter must in all circumstances be maintained below 150 o C. From the activation point of view, the chromium content can be an additional advantage. Due to lack of information, especially threse to lack of information, especially threshold propagation data, the mechanical behaviour and loss of some important properties could not be assessed for periods as long as 40 years; among them, resistance to fatigue and in service material toughness, which are RPV life limiting factors. Nevertheless, based on shorter experience, 6061-T6 alloy could be used, provided a proper surveillance programme is carried out, which with this material could be efficiently done, in view of its mechanical characteristics. (author)

  9. Characterization of semi-solid processing of aluminium alloy 7075 with Sc and Zr additions

    Energy Technology Data Exchange (ETDEWEB)

    Rogal, ?., E-mail: l.rogal@imim.pl [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Dutkiewicz, J. [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Atkinson, H.V. [The University of Leicester, Department of Engineering University Road, Leicester, LE1 7RH (United Kingdom); Lity?ska-Dobrzy?ska, L.; Czeppe, T. [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Modigell, M. [RWTH Aachen—Department of Mechanical Process Engineering, 55 Templergraben St., Aachen (Germany)

    2013-09-15

    For thixoforming (semi-solid processing) it is necessary to have a fine globular microstructure in a semi-solid range. Here this has been obtained for 7075 aluminium alloy by addition of modifying agents: 0.5 weight % of scandium and zirconium. The thixoforming process was carried out at 632 °C which gave about 23 volume % of liquid phase. The microstructure of the thixo-formed part (a rotor) consisted of globular grains surrounded by precipitates of secondary phase. The average hardness of thixo-formed parts was 105 HV{sub 5} and the tensile strength 300 MPa. T6 heat treatments were performed with solutionisation at 450 °C for 30 min and 10 h. In both cases the ageing time was set as 18 h at 120 °C. The heat treatments led to an increase in average tensile strength up to 495 MPa. Transmission Electron Microscopy (TEM) analysis enabled the identification of precipitates of the metastable dispersoids of L1{sub 2}–Al{sub 3} (Zr, Sc) and ?? (MgZn{sub 2}) phases in the alloy after the thixoforming and T6 treatment. The measurements of rheological properties of 7075Al alloy with Sc and Zr additions in the semi-solid range indicated an increase of particle size and spheroidization leading to an observable decrease of viscosity during isothermal shearing. A shear rate jump experiment showed that with increasing shear rate the viscosity rapidly falls.

  10. Characterization of semi-solid processing of aluminium alloy 7075 with Sc and Zr additions

    International Nuclear Information System (INIS)

    For thixoforming (semi-solid processing) it is necessary to have a fine globular microstructure in a semi-solid range. Here this has been obtained for 7075 aluminium alloy by addition of modifying agents: 0.5 weight % of scandium and zirconium. The thixoforming process was carried out at 632 °C which gave about 23 volume % of liquid phase. The microstructure of the thixo-formed part (a rotor) consisted of globular grains surrounded by precipitates of secondary phase. The average hardness of thixo-formed parts was 105 HV5 and the tensile strength 300 MPa. T6 heat treatments were performed with solutionisation at 450 °C for 30 min and 10 h. In both cases the ageing time was set as 18 h at 120 °C. The heat treatments led to an increase in average tensile strength up to 495 MPa. Transmission Electron Microscopy (TEM) analysis enabled the identification of precipitates of the metastable dispersoids of L12–Al3 (Zr, Sc) and ?? (MgZn2) phases in the alloy after the thixoforming and T6 treatment. The measurements of rheological properties of 7075Al alloy with Sc and Zr additions in the semi-solid range indicated an increase of particle size and spheroidization leading to an observable decrease of viscosity during isothermal shearing. A shear rate jump experiment showed that with increasing shear rate the viscosity rapidly falls

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

    Science.gov (United States)

    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.

  12. Microstructure and tensile properties of heavily irradiated 5052-0 aluminium alloy

    International Nuclear Information System (INIS)

    During neutron irradiation of an Al-2.2% Mg solid solution alloy in the High Flux Isotope Reactor to fast and thermal fluences > 1027 neutrons(n)/m2 at 328 K (0.35 Tsub(m)) about seven percent insoluble, transmutant silicon was produced. Some of this silicon reacted with the dissolved magnesium to form a fine precipitate of Mg2Si. A tight dislocation structure was also created. The alloy showed good resistance to cavity formation. These microstructural features are responsible for pronounced strengthening and an associated marked loss in ductility as revealed by tensile tests at 323, 373, and 423 K (0.35, 0.40 and 0.45 Tsub(m)). These changes were greater than in magnesium-free aluminium and in alloys containing preexisting, thermally-aged Mg2Si precipitate. Increasing the thermal-to-fast flux ratio from 1.7 to 2.1 caused further strengthening beyond that expected from a simple increase in silicon level. (orig.)

  13. Mechanical alloying for fabrication of aluminium matrix composite powders with Ti-Al intermetallics reinforcement

    Directory of Open Access Journals (Sweden)

    M. Adamiak

    2008-12-01

    Full Text Available Purpose: The aim of this work is to report the effect of the high energy milling processes, on fabrication ofaluminium matrix composite powders, reinforced with a homogeneous dispersion of the intermetallic Ti3Alreinforcing particles.Design/methodology/approach: MA process are considered as a method for producing composite metalpowders with a controlled fine microstructure. It occurs by the repeated fracturing and re-welding of powdersparticles mixture in a highly energetic ball mill.Findings: Mechanical alloying, applied for composite powder fabrication, improves the distribution of theTi3Al intermetallic reinforcing particles throughout the aluminium matrix, simultaneously reducing their size.Observed microstructural changes influence on the mechanical properties of powder particles.Research limitations/implications: Contributes to the knowledge on composite powders production via MA.Practical implications: Gives the answer to evolution of the powder production stages, during mechanicalalloying and theirs final properties.Originality/value: Broadening of the production routes for homogeneous particles reinforced aluminium matrixcomposites.

  14. Optimization of Process Parameters to enhance the Hardness on Squeeze Cast Aluminium Alloy AA6061

    Directory of Open Access Journals (Sweden)

    M. Thirumal Azhagan

    2014-03-01

    Full Text Available The automotive and aerospace industries have been the main driving force behind the search of new production processes which are capable of producing components with high integrity. Squeeze casting is one such novel metal processing technique which combines the advantages of both casting and forging in one operation. Squeeze casting process is suited for all melting ranges of metals varying from lead to iron. But nowadays, light weight materials like aluminium and magnesium are mostly used in the industries. Aluminium alloy AA6061 is one such futuristic material that is widely used to produce automotive and aerospace components. Although the squeeze casting process has many obvious advantages in producing parts of light metals that can be utilized in structural applications, the full potential can only be realized after the process parameters have been optimized. In this attempt, cylindrical components of AA6061 were produced using squeeze casting process and their hardness values were found out. The optimal process parameter combination to obtain maximum hardness was calculated using Taguchi method and Genetic Algorithm approaches. It was observed that Genetic Algorithm yielded better solution when compared to the solution provided by Taguchi Method.

  15. Influence of friction stir welding parameters on properties of 2024 T3 aluminium alloy joints

    Directory of Open Access Journals (Sweden)

    Eramah Abdsalam M.

    2014-01-01

    Full Text Available The aim of this work is to analyse the process of friction stir welding (FSW of 3mm thick aluminium plates made of high strength aluminium alloy - 2024 T3, as well as to assess the mechanical properties of the produced joints. FSW is a modern procedure which enables joining of similar and dissimilar materials in the solid state, by the combined action of heat and mechanical work. This paper presents an analysis of the experimental results obtained by testing the butt welded joints. Tensile strength of the produced joints is assessed, as well as the distribution of hardness, micro-and macrostructure through the joints (in the base material, nugget, heat affected zone and thermo-mechanically affected zone. Different combinations of the tool rotation speed and the welding speed are used, and the dependence of the properties of the joints on these parameters of welding technology is determined. [Projekat Ministarstva nauke Republike Srbije, br. TR 34018 i br. TR 35006

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

    International Nuclear Information System (INIS)

    Anodic layer growth on 2024 aluminium alloy at 70 deg. 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 (0.4 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 deg. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V. [Laboratoire de Chimie des Materiaux et Interfaces (LCMI), 16 route de Gray, 25 030 Besancon Cedex (France)]. E-mail: virginie.moutarlier@univ-fcomte.fr; Pelletier, S. [Laboratoire de Chimie des Materiaux et Interfaces (LCMI), 16 route de Gray, 25 030 Besancon Cedex (France); Lallemand, F. [Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), Chemistry Department, Facultes Universitaires Notre Dame de la Paix, 61, Rue de Bruxelles, B-5000 Namur (Belgium); Gigandet, M.P. [Laboratoire de Chimie des Materiaux et Interfaces (LCMI), 16 route de Gray, 25 030 Besancon Cedex (France); Mekhalif, Z. [Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), Chemistry Department, Facultes Universitaires Notre Dame de la Paix, 61, Rue de Bruxelles, B-5000 Namur (Belgium)

    2005-12-15

    Anodic layer growth on 2024 aluminium alloy at 70 deg. C, under 40 V, during 60 min, in 50 g L{sup -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 deg. 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.

  18. Development of the electron beam welding of the aluminium alloy 6061-T6 for the Jules Horowitz reactor

    International Nuclear Information System (INIS)

    The aluminium alloy 6061-T6 has been selected for the construction of the Jules Horowitz's reactor vessel. This reactor vessel is pressurized and will be made through butt welding of ? 2 cm thick aluminium slabs. The electron beam welding process has been tested and qualified. It appears that this welding process allows: -) welding without pre-heating, -) vacuum welding, -) welding of 100% of the thickness in one passage, -) very low deforming welding process, -) very low density and very low volume of blow holes, -) weak ZAT (Thermal Affected Zones), and -) high reproducibility that permits automation. (A.C.)

  19. Passivation of screen-printed aluminium-alloyed emitters for back junction n-type silicon solar cells

    OpenAIRE

    Rauer, M.; Schmiga, C.; Hermle, M.; Glunz, S. W.

    2009-01-01

    We present a detailed study on effectively surface-passivated aluminium-doped p+ emitters to further enhance the efficiency of our n-type silicon solar cells featuring a full-area screen-printed Al-alloyed rear emitter. We investigated two different passivation layers both well suited for highly doped p+ silicon: plasma-enhancedchemical- vapour-deposited amorphous silicon (a-Si) and atomic-layer-deposited aluminium oxide (Al2O3). We show that for an effective emitter passivation (i) a careful...

  20. Towards 20% efficient n-type silicon solar cells with screen-printed aluminium-alloyed rear emitter

    OpenAIRE

    Schmiga, C.; Hermle, M.; Glunz, S. W.

    2008-01-01

    We present n-type silicon solar cells featuring an effectively passivated full-area screen-printed aluminium-alloyed rear emitter. Two different passivation stacks for Al-p+ emitters are investigated: The first one consists of a plasma-enhanced-chemical-vapour-deposited amorphous silicon film covered by a plasma silicon oxide layer, the second one of a plasma-assisted atomic-layer-deposited aluminium oxide also covered by a plasma silicon oxide. For our a-Si/SiOx-passivated back junction n+np...

  1. Microstructure strengthening mechanisms in an Al–Mg–Si–Sc–Zr equal channel angular pressed aluminium alloy

    International Nuclear Information System (INIS)

    Microstructure dislocation strengthening mechanisms in severely deformed aluminium strongly depend on the different boundary evolutions. Thereafter, models of proof stress determination should take into account the different nature of the boundaries that form during severe plastic deformation. In the last few decades, Hall–Petch modified relationship and other proof stress modelling were extensively discussed. This paper deals with further insights into the Hansen's and other authors approach to the modelling of aluminium poof stress after equal channel angular pressing. The present model is based on a detailed transmission electron microscopy microstructure characterization of the different strengthening contributions in an age-hardened Al–Mg–Si–Sc–Zr alloy.

  2. Microstructure mapping in friction stir welds of 7449 aluminium alloy using SAXS

    International Nuclear Information System (INIS)

    This paper describes the microstructural response of an age-hardenable, high-strength 7449 aluminium alloy to friction stir welding. Plates in the naturally aged (T3) and over-aged (T79) conditions were welded using two weld tool translation speeds. Maps of precipitate volume fraction and size were obtained by spatially resolved small-angle X-ray scattering over a cross-section of the welded plate, complemented by direct observations made by transmission electron microscopy. The spatial variations of precipitate volume fraction and size were assessed quantitatively for the characteristic zones of the welds, and supported by complementary hardness measurements. The effect of initial microstructure and welding speed, in particular in the heat-affected and thermomechanically affected zones, is discussed

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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.

  5. An investigation into some mechanical and metallurgical properties of stainless steel reinforced aluminium alloy powder compacts

    International Nuclear Information System (INIS)

    An experimental investigation into uniaxial tension and transverse bending of thin rectangular sheets made of stainless steel wire mesh and micro cable reinforced sintered 6061 aluminium alloy powder compacts was made in order to determine some of their mechanical and metallurgical properties. Theoretical predictions based on the rule of mixtures were made for the ultimate tensile strength and for the Young's modulus and the results were compared . Metallographic analysis involved optical and SEM photography on selected specimens and also an 'EDAX' analysis on the intermetallic phase formed between the matrix and the reinforcement in order to establish its composition. In general, it was observed that the introduction of the stainless steel reinforcement resulted in extra proportional strength of the reinforced material that outweighs based on the net density of the combination. (author)

  6. Emittance of boehmite and alumina films on 6061 aluminium alloy between 295 and 773 K

    International Nuclear Information System (INIS)

    The total hemispherical emittance of an oxide film that formed on 6061-T6 aluminium alloy parts in the Tower Shielding Reactor-II at Oak Ridge National Laboratory was measured from 295 to 773 K using an emissometer and/or a calorimeter. The emittance of this film was critically needed for heat transfer calculations in a simulated loss-of-coolant accident of the reactor. X-ray diffraction analysis identified the film as boehmite (Al2O3 x H2O), which dehydrated to alumina (Al2O3) upon heating above 473 K. The measured emittances for the alumina film are in excellent agreement with published values for anodized aluminum films and for bulk alumina. Published values of the emittance of boehmite could not be found for comparison, but evidence is presented that some anodization processes for aluminum yield boehmite and not alumina films

  7. Hot-crack test for aluminium alloys welds using TIG process

    Directory of Open Access Journals (Sweden)

    Deschaux-beaume F.

    2010-06-01

    Full Text Available Hot cracking is a critical defect frequently observed during welding of aluminium alloys. In order to better understand the interaction between cracking phenomenon, process parameters, mechanical factors and microstructures resulting from solidi?cation after welding, an original hot-cracking test during welding is developed. According to in-situ observations and post mortem analyses, hot cracking mechanisms are investigated, taking into account the interaction between microstructural parameters, depending on the thermal cycles, and mechanical parameters, depending on geometry and clamping conditions of the samples and on the thermal ?eld on the sample. Finally, a process map indicating the limit between cracking and non-cracking zones according to welding parameters is presented.

  8. Microscopic Study of 5083-H321 Aluminium Alloy Under Fretting Fatigue Condition

    Energy Technology Data Exchange (ETDEWEB)

    Eslamian, S; Sahari, B B [Institute Advanced Technology, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Ali, Aidy [Department of Mechanical and Manufacturing Engineering Faculty of Engineering, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Mahdi, El-Sadiq; Hamouda, A M, E-mail: saeed.eslamian@gmail.com [Mechanical and Industrial Engineering Department, College of Engineering, Qatar University 2713 Doha (Qatar)

    2011-02-15

    Fretting occurs where there is small amplitude oscillating motion between solid surfaces in contact. With even small loads or prolonged operation, fretting may lead to crack initiation followed by fretting fatigue. Its effect on fatigue is to speed up the nucleation of fatigue surface cracks and it can be extremely damaging. Fretting fatigue is a critical concern in aircraft structures and a widespread problem in naval structural components and is often the root cause of fatigue crack nucleation in machine components. In this investigation, fretting fatigue study is carried out using 5083-H321 marine/ aerospace aluminium alloy. The test rig and the experiments were designed with an emphasis to study the crack initiation behaviour in the fretted region using scanning electron microscope (SEM). Fretting damage and its relationship to the fretting fatigue life are presented and discussed.

  9. The effects of microstructure on the stress corrosion cracking characteristics of 7050 high strength aluminium alloy

    International Nuclear Information System (INIS)

    A 7050 high strength aluminium alloy was processed by three different methods to obtain the microstructures containing a large amount of deformed grains and the ones containing considerable amount of subgrains and recrystallized grains, respectively. The differences of the microstructure before and after T6 temper were investigated by optical and electron microscopes, and the average stress corrosion crack velocity vs. the stress intensity factor was measured by precracked CT specimens. The effect of the grain characteristics on the stress corrosion cracking susceptibility was more pronounced before T6 temper then after T6 temper. The resistance of the materials containing deformed grains and subgrains to stress corrosion cracking was superior to that of the materials containing recrystallized grains. The stress corrosion cracking susceptibility depended largely on the behavior of grain-boundary precipitates. (Author)

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

    Directory of Open Access Journals (Sweden)

    Bianchi S.

    2012-08-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  12. Residual Stress Analysis on High-Speed Face Milling of AA 7075-T6 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    F.V. Díaz

    2012-08-01

    Full Text Available Different states of residual stress generated by high-speed face milling in specimens of AA 7075-T6 aluminium alloy were meticulously evaluated. This assessment was carried out along the symmetry axes of the generated surfaces, and also in the centroids corresponding to the conventional and climb cutting zones. An indentation method, based on the use of a universal measuring machine, was employed to determine the normal and shear components of residual stress. It is noteworthy that the use of this method makes possible to significantly reduce the absolute error of measurement. Different Mohr's circles were evaluated to compare the residual stress states introduced in the conventional and climb cutting zones. Finally, the results were analyzed in terms of mechanical and thermal effects generated in the primary cutting zone.

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

    Science.gov (United States)

    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. PMID:20500429

  14. Natural aging behaviour of friction stir welded 6005A-T6 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Peng; Sun, Daqian; Li, Hongmei, E-mail: lihongmei@jlu.edu.cn

    2013-08-01

    By local thermal cycles and hardness measurements, supported by transmission electron microscopy, the post-weld natural aging behaviour of friction stir welded 6005A-T6 aluminium alloy was investigated. The results show that the softening in the nugget zone and thermo-mechanically affected zone immediately after welding is mainly caused by the high peak temperatures and rapid cooling rates, resulting in the original ?? precipitates dissolving and restraining re-precipitation. On the one hand, the hardness recovery in both microstructural zones during post-weld natural aging is attributed to the formation of clusters or GP zones depending on the natural aging time. On the other hand, the softening in the heat-affected zone after welding is due to the transformation of the ??? to ?? precipitates and the precipitation of Q?. Natural aging has little effect on the microstructure and hardness of the heat-affected zone. The mechanism of natural aging behaviour was discussed.

  15. Microstructural evolution and properties of friction stir welded aluminium alloy AA2219

    International Nuclear Information System (INIS)

    Low weld strength of fusion welded joints of aluminium alloy AA2219 is a concern in fabrication of pressure vessels and is attributable to the presence of weld defects, as well as various metallurgical factors. Friction stir welding (FSW), being a solid state joining process has obvious advantages over fusion welding. Results of preliminary FSW experiments conducted on 10 mm thick plate using a particular tool configuration are presented here. Microscopic studies show the presence of very fine equiaxed recrystallised grain at the weld nugget and a flow pattern of grains due to heavy deformation in defect-free weld coupons. Mechanical properties are correlated with the microstructure and process variables. Fractographic analysis complements the observations of optical microscopy and mechanical properties

  16. Friction Stir Processing of an AlSi6Cu4 cast aluminium alloy

    Directory of Open Access Journals (Sweden)

    M.St. W?glowski

    2011-04-01

    Full Text Available The present paper deals with the Friction Stir Processing (FSP of an AlSi6Cu4 cast aluminium alloy. The emphasis was placed on thedetermination of an influence FSP parameters and the torque action on the tool. It was found that an increase in rotational speed of the tool causes a decrease in the torque. Simultaneously, the results showed that an increase in travelling speed of the tool brings about an increase in the torque. The metallographic examination of the processed surface layer of the material has shown that the depth of the layer in which the microstructure was modified by the shoulder action depends to a large extent on the rotation speed and to a lesser extent on the travelling speed.

  17. Natural aging behaviour of friction stir welded 6005A-T6 aluminium alloy

    International Nuclear Information System (INIS)

    By local thermal cycles and hardness measurements, supported by transmission electron microscopy, the post-weld natural aging behaviour of friction stir welded 6005A-T6 aluminium alloy was investigated. The results show that the softening in the nugget zone and thermo-mechanically affected zone immediately after welding is mainly caused by the high peak temperatures and rapid cooling rates, resulting in the original ?? precipitates dissolving and restraining re-precipitation. On the one hand, the hardness recovery in both microstructural zones during post-weld natural aging is attributed to the formation of clusters or GP zones depending on the natural aging time. On the other hand, the softening in the heat-affected zone after welding is due to the transformation of the ??? to ?? precipitates and the precipitation of Q?. Natural aging has little effect on the microstructure and hardness of the heat-affected zone. The mechanism of natural aging behaviour was discussed

  18. Finite element simulations of the Portevin Le Chatelier effect in aluminium alloy

    Science.gov (United States)

    Hopperstad, O. S.; Børvik, T.; Berstad, T.; Benallal, A.

    2006-08-01

    Finite element simulations of the Portevin-Le Chatelier effect in aluminium alloy 5083-H116 are presented and evaluated against existing experimental results. The constitutive model of McCormick (1988) for materials exhibiting negative steady-state strain-rate sensitivity is incorporated into an elastic-viscoplastic model for large plastic deformations and implemented in LS-DYNA for use with the explicit or implicit solver. Axisymmetric tensile specimens loaded at different strain rates are studied numerically, and it is shown that the model predicts the experimental behaviour with reasonable accuracy; including serrated yielding and propagating bands of localized plastic deformation along the gauge length of the specimen at intermediate strain rates.

  19. Corrosion properties of aluminium alloys and surface treated alloys in tap water

    OpenAIRE

    Gustafsson, Sofia

    2011-01-01

    The aim of this thesis is to obtain a basic knowledge of the factors that affect corrosion of aluminium in tap water for different kinds of applications like water pipes for tap water, solar systems, HVAC&R-applications (like fan coil units on chillers) and heat sinks for electronic or industrial applications. Open systems are used in some applications and closed systems in others. There is a clear difference in the corrosion behaviour of these two systems. The main reasons for this diffe...

  20. Evaluation of the load-carrying capacity of hard coatings deposited onto a 7075-T6 aluminium alloy

    International Nuclear Information System (INIS)

    In the present work, the effect of the thickness of an electroless NiP load-support interlayer coating, on the initiation and development of plastic deformation in a 7075-T6 aluminium alloy substrate coated with a duplex coatings has been investigated. The duplex system has been obtained by means of the deposition of an electroless Ni-11 wt.% P (EN) onto the aluminium alloy substrate, followed by the deposition of a ZrN film (PVD) on top of the EN coating. The duplex systems that were investigated involved two different EN deposits, with thicknesses of 30 and 60 mm, respectively. The coatings were characterized regarding their morphology, thickness and absolute hardness. Indentation tests with spherical ind enters were performed employing 6 mm diameter WC-6Co balls and normal loads of 10,15, 25,50 and 75 N. All the indentations were modeled by means of the Elastic 2.1. code, in order to determine the through-thickness von Misses effective stress profile of the samples and the critical load for the initiation of the plastic deformation of the aluminium alloy substrate. the experimental results have been validate by means of such a theoretical analysis. it has been determined that the duplex system with an EN interlayer of 30 mm does not constitute a satisfactory load-support interlayer, for the load values employed in the tests. However, for the coated system with an EN interlayer of 60 mm, the critical load for the initiation of plastic deformation in the aluminium alof plastic deformation in the aluminium alloy substrate was found to be?16N, which indicates that such a load-support interlayer avoids the plastic deformation of the substrate at normal loads less than ? 15 N. (Author) 21 refs

  1. Fracture mechanisms of aluminium alloy AA7075-T651 under various loading conditions

    International Nuclear Information System (INIS)

    The fracture behaviour of the aluminium alloy AA7075-T651 is investigated for quasi-static and dynamic loading conditions and different stress states. The fracture surfaces obtained in tensile tests on smooth and notched axisymmetric specimens and compression tests on cylindrical specimens are compared to the fracture surfaces that occur when a projectile, having either a blunt or an ogival nose shape, strikes a 20 mm thick plate of the aluminium alloy. The stress state in the impact tests is much more complex and the strain rate significantly higher than in the tensile and compression tests. Optical and scanning electron microscopes are used in the investigation. The fracture surface obtained in tests with smooth axisymmetric specimens indicates that the crack growth is partly intergranular along the grain boundaries or precipitation free zones and partly transgranular by void formation around fine and coarse intermetallic particles. When the stress triaxiality is increased through the introduction of a notch in the tensile specimen, delamination along the grain boundaries in the rolling plane is observed perpendicular to the primary crack. In through-thickness compression tests, the crack propagates within an intense shear band that has orientation about 45o with respect to the load axis. The primary failure modes of the target plate during impact were adiabatic shear banding when struck by a blunt projectile and ductile hole-enlargement when struck by an ogival projectile. Delamination and fragmentation of the plates occurred for both loading cases, but was stronger for the ogival projectile. The delamination in the rolling plane was attributed to intergranular fracture caused by tensile stresses occurring during the penetration event.

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

    Science.gov (United States)

    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. PMID:21145675

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

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.S., E-mail: jeremy.robinson@ul.ie [Materials and Surface Science Institute, University of Limerick (Ireland); Tanner, D.A. [Materials and Surface Science Institute, University of Limerick (Ireland); Truman, C.E. [Department of Mechanical Engineering, University of Bristol (United Kingdom); Paradowska, A.M. [ISIS Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); Wimpory, R.C. [Helmholtz Centre Berlin for Materials and Energy, Hahn Meitner Platz 1, Berlin (Germany)

    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 of 7075 promotes significant microstructural differences to 7010. Black-Right-Pointing-Pointer When precipitation is accounted for, residual stress in both forgings are similar.

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

    International Nuclear Information System (INIS)

    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. S 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: ? Through thickness residual stress measurements made on large Al alloy forgings. ? Residual stress characterised using neutron diffraction and deep hole drilling. ? Biaxial compressive surface and triaxial subsurface residual stresses. ? Quench sensitivity of 7075 promotes significant microstructural differences to 7010. ? When precipitation is accounted for, residual stress in both forgings are similar.

  5. Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Gudla, Visweswara Chakravarthy

    2015-01-01

    Aluminium alloys were treated with steam of varying vapour pressures which resulted in the growth of aluminium oxyhydroxide layers of an average thickness of ~450–825 nm. The microstructure and composition of the generated layers were characterised by GD-OES, FEG-SEM, GI-XRD and TEM. The thickness of the oxide layeras well as the compactness increased with steam vapour pressure. The increase in vapour pressure also resulted in a better coverage over the intermetallic particles. Oxide layer showed a layered structure with more compact layer at the Al interface and a nano-scale needle like structure at the top. The kinetics of formation of film understeamwas rapid; approx. 350nm thick layers were generated within 5 s of steam treatment, however increase in thickness of the oxide retarded further growth. The enrichment or depletion of different alloying elements at the surface of aluminium as a result of alkaline etching pre-treatment influenced the thickness and growth of theoxide. Moreover the steam treatment resulted in the partial oxidation of second phase intermetallic particles present in the aluminium alloy microstructure.

  6. Microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system.

    Science.gov (United States)

    Yang, S S; Lin, J Y; Lin, Y T

    1998-09-01

    To investigate the microbiologically induced corrosion of aluminum alloys in fuel-oil/aqueous system, aluminum alloys A356, AA 5052, AA 5083 and AA 6061 were chosen as the test alloys and Cladosporium and several fuel-oil contaminated microbes isolated in Taiwan were used as test organisms. Aluminum alloy AA 5083 in fuel-oil/aqueous system was the most susceptible material for microbial corrosion, then followed by aluminum alloys AA 5052 and A356, and AA 6061 was more resistant to microbial aggression. Mixed culture had high capability of corrosion, then followed by Penicillium sp. AM-F5, Fusarium sp. AM-F1, Pseudomonas aeruginosa AM-B5, Ps. fluorescens AM-B9, C. resinae ATCC 22712, Penicillium sp. AM-F2, Candida sp. AM-Y1 and Ps. aeruginosa AM-B11. From energy dispersive spectrometer analysis, aluminum and magnesium contents decreased in the corrosion area, while chlorine and sulfur contents increased. The major organic acid produced in fuel-oil/aqueous system was acetic acid, and the total organic acids content had a positive correlation with the degree of microbial corrosion. PMID:10496152

  7. Reduction of porosity content generated during Nd:YAG laser welding of A356 and AA5083 aluminium alloys

    International Nuclear Information System (INIS)

    Porosity formation is greatly influenced in aluminium alloys by the low vaporisation point element (Mg, Zn) content, or by process instability such as key-hole closures that tend to entrap occluded gases during welding. Another important contribution comes from the hydrogen content, because of a very high solubility in molten aluminium that favours microporosity generation. In this paper, cw YAG laser welds on two aluminium alloys were carried out: a AA5083-O wrought alloy with a high Mg content (4.5%) and a A356 cast alloy with 7% Si and a cast oxide layer. The porosity content in laser beads was extensively studied, with the use of different experimental method (X-ray radiography+image analysis, tomography), in order to check the influence of mechanical surface preparation as well as process parameters (single or dual spot, different welding speeds). It was concluded that surface preparation as well as dual beam welding are adequate methods for reducing porosity formation tendency in laser assemblies

  8. Effect of Cathodic Adsorbed Hydrogen on Industrial Aluminium Alloy AA 5083 Corrosion Induced by Elemental Mercury in LNG Industries

    Directory of Open Access Journals (Sweden)

    D. Zerouali

    2006-01-01

    Full Text Available Natural gases contain impurities such as mercury and water, which both act simultaneously and cause a significant corrosion of aluminium alloys constituting the cryogenic exchangers tubes used in the industries of natural gas liquifaction. Corrosion creates many problems of liquifaction units (Groningen (Holland, Skikda, Bethioua (Algeria. The process of corrosion begins with an adsorption of mercury on aluminium surfaces, the formation of an amalgam and an electrochemical oxidation of aluminium. The cathodic process is recognized as hydrogen evolution which occurs with a high overpotential on mercury and produces free radical H. which enhanced oxidation of aluminium and diffused in metal bulk causing stress corrosion. The effect of cathodically adsorbed hydrogen on amalgamated surfaces was not developed in previous studies of aluminium corrosion; this is the object of this study. Potentiodynamic techniques on amalgamated industrial alloy AA 5083 have been used in this study. The results show different anodic behaviors depending on the pH of the medium and cathodic polarisation. For pH values less than 4, anodic behaviour of amalgamated electrodes gave two oxidation peaks at respective constant potentials of -1.40 and -1.25 volt/SCE; the current peaks increased with a decrease of pH. The first peak (E = -1.40 volt /SCE occurred in all experiments and showed oxidation of aluminium. The second peak (E = -1.25 volt/SCE appeared for a pH less than 4 and for a long time of cathodic polarisation, this peak showed an oxidation of adsorbed hydrogen. Evolution of intensities of the anodic peaks indicated the relation between rate of cathodic hydrogen adsorbed which depend on pH and on the time of exposure of amalgamated electrodes in aqueous solutions and on time of cathodic polarisation. The corrosion currents decreased very appreciably for a pH ranging between 4 and 8 corresponding to the passive domain of aluminium and aluminium alloys showing anomalous behaviour in presence of mercury. The corrosion potential varied between -1.52 to -1.62 volt/SCE at a pH of 1 to 13 reflecting a very active electrode. SEM observation of corroded electrodes showed different corrosions: stress corrosion, general corrosion and pitting.

  9. Wear Properties of Thixoformed and High Pressure Die Cast Aluminium Alloys for Connecting Rod Applications in Compressors

    Science.gov (United States)

    Birol, Yücel; Birol, Feriha

    2007-04-01

    Hypereutectic aluminium casting alloys are attractive candidates for connecting rod applications in compressors. The wear properties of these alloys are largely controlled by their microstructural features which in turn are affected by the processing route. Several hypo- and hypereutectic Al-Si alloys were produced by high pressure die casting and thixoforming in the present work. The former route produced a very fine microstructure while relatively coarser, globular ?-Al matrix dominated in thixoformed grades. A modified Falex Block on Ring equipment was employed to investigate the wear properties of these alloys. Wear tests were carried out under service conditions in the lubricated state at 75°C. The superior wear properties of hypereutectic alloys produced by high pressure die casting with respect to the thixoformed variety is accounted for by the very fine microstructure with a fine dispersion of primary Si particles in the former. Of the two production routes employed, thixoforming had a favorable effect on wear properties at equal Si levels.

  10. Wear Properties of Thixoformed and High Pressure Die Cast Aluminium Alloys for Connecting Rod Applications in Compressors

    International Nuclear Information System (INIS)

    Hypereutectic aluminium casting alloys are attractive candidates for connecting rod applications in compressors. The wear properties of these alloys are largely controlled by their microstructural features which in turn are affected by the processing route. Several hypo- and hypereutectic Al-Si alloys were produced by high pressure die casting and thixoforming in the present work. The former route produced a very fine microstructure while relatively coarser, globular ?-Al matrix dominated in thixoformed grades. A modified Falex Block on Ring equipment was employed to investigate the wear properties of these alloys. Wear tests were carried out under service conditions in the lubricated state at 75 deg. C. The superior wear properties of hypereutectic alloys produced by high pressure die casting with respect to the thixoformed variety is accounted for by the very fine microstructure with a fine dispersion of primary Si particles in the former. Of the two production routes employed, thixoforming had a favorable effect on wear properties at equal Si levels

  11. Investigation on the Change Effected by the Tool Type on the Hardness of Friction Stir Processed AA6063 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    K. Ganesa Balamurugan

    2012-01-01

    Full Text Available Aluminium alloy 6063 is one of the most popular alloys in the 6000 series which provides good extrudability and surface finish. Various application of this alloy include architectural and building products, electrical components and conduit, pipes for irrigation systems, door and window frames, railings and furniture, etc. However improving its strength by improving the hardness would complement the existing advantages of this alloy. This study was intended to improve the hardness of this alloy by FSP (friction stir processing technique. The effect of two tool types on the hardness of the friction stir processed surfaces was studied. It was found that the hardness values of the friction stir processed surfaces varied between the tool types. The surfaces processed with both tool types show considerable improvement in the hardness when compared to the hardness of the unprocessed bulk material. Experiments were conducted as per full factorial 23 design of experiment with various process parameter combinations for both tools.

  12. Influence of molybdenum ion implantation on the localized corrosion resistance of a high strength aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, C.M.; Cristobal, M.J.; Figueroa, R. [Department of Materials Science, University of Vigo, 36310 Vigo (Spain); Pena, G., E-mail: gpena@uvigo.es [Department of Materials Science, University of Vigo, 36310 Vigo (Spain)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Mo implanted 7075 aluminium alloy in T6 and T73 conditions is studied. Black-Right-Pointing-Pointer After implantation Mo is not bonded to Al forming a new phase. Black-Right-Pointing-Pointer Significant improvement in corrosion resistance of Mo implanted T6 alloy is detected. Black-Right-Pointing-Pointer Limited effect or even harmful in the Mo-implanted T73 samples. Black-Right-Pointing-Pointer Analysis of EIS spectra highlights induced changes in the corrosion mechanism. - Abstract: The effect of Mo{sup +} implantation on corrosion properties of AA 7075 (T6 and T73) has been studied. The induced modifications in the surfaces have been analysed by XPS and GAXRD. EXCO tests and electrochemical DC and AC techniques have been used to characterize the localized corrosion resistance. The effect of implantation is highly dependent on the ageing conditions. A marked increasing of the impedance of T6 samples after implantation has been measured, while the effect of Mo on T73 samples is less clear. Impedance spectra allow analysing the differences in the evolution of localized corrosion between both tempers.

  13. Oxide growth on aluminium alloys in the presence of ammonium fluoborate

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, J.; Paterson, P.; Flavell, T. [Royal Melbourne Inst. of Tech., VIC (Australia); Biddle, G. [Alcoa Rolled Products (Australia)

    1996-12-31

    The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH{sub 4}BF{sub 4}. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH{sub 4}BF{sub 4} atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig.

  14. MICROSTRUCTURAL CHARACTERISATION AND CORROSION BEHAVIOUR OF TOP SURFACE OF TIG WELDED 2219?T87 ALUMINIUM ALLOY

    Directory of Open Access Journals (Sweden)

    G. Venkatasubramanian

    2013-03-01

    Full Text Available The microstructural characterisation and corrosion behaviour of top surface of tungsten inert gas (TIG welded 2219?T87 aluminium alloy (AA2219–T87 in 0.6 M NaCl solution was studied by optical microscopy, scanning electron microscopy (SEM, potentiodynamic polarisation, and electrochemical impedance spectroscopy (EIS. The optical microscopy and SEM analyses revealed that the welding of base metal (BM with ER2319 filler alloy caused the formation of micro pores and micro cracks on the surface of weld zone (WZ while the welding heat caused the dissolution and segregation of CuAl2 intermetallic particles along the grain boundaries in the heat affected zone (HAZ. The anodic and cathodic branches of polarisation curves showed that the HAZ has lower corrosion resistance than WZ and BM. The decrease of charge transfer resistance of HAZ when comparedto WZ and BM obtained by electrochemical impedance spectroscopy (EIS further confirmed its higher corrosion rate in 0.6 M NaCl solution.

  15. Oxide growth on aluminium alloys in the presence of ammonium fluoborate

    International Nuclear Information System (INIS)

    The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH4BF4. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH4BF4 atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg C , AA5182 alloys undergo incipient melting at the grain boundaries with magnesium diffusing through to the surface. 5 refs., 1 fig

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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. PMID:20494588

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

    International Nuclear Information System (INIS)

    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 CO2 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

  19. Neutron and synchrotron measurements of residual strain in TIG welded aluminium alloy 2024

    International Nuclear Information System (INIS)

    Tungsten inert gas (TIG) welding is one method of joining aluminium alloys with potential application in the aerospace industry. However, for it to be seriously considered as an alternative to mechanical fasteners the interrelated problems of residual stress and distortion need to be addressed. In this paper neutron, laboratory and synchrotron X-ray diffraction methods are used to provide non-destructive information about the residual stress field in TIG-welded 2024 Al alloy. The results compare well despite the differing penetration and sampling volumes associated with each technique. It is found that the magnitudes of the tensile longitudinal stresses decrease along the plate due to progressive heating up of the plate ahead of the arc during welding, so that steady-state conditions are not achieved. Comparison of the data with a finite element model indicates that softening of the heat-affected region must be included to simulate the resulting stress field. The FE model is found to be in good agreement with the data especially in the vicinity of the weld slope-out

  20. Vacuum brazing of aluminium metal matrix composite (55 vol.% SiC{sub p}/A356) using aluminium-based filler alloy

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Jitai, E-mail: niujitai@163.com [Harbin Institute of Technology (China); Zhengzhou University (China); Luo, Xiangwei; Tian, Hao [Zhengzhou University (China); Brnic, Josip [University of Rijka (Croatia)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer The proper filler metal has been developed, especially for contents of Mg and Si. Black-Right-Pointing-Pointer The pressure device has been designed for specimen in vacuum brazing process. Black-Right-Pointing-Pointer The accurate measurement method for shear strength of lap joint has been found. Black-Right-Pointing-Pointer The brazing temperature of 560 Degree-Sign C has been optimised. Black-Right-Pointing-Pointer The micro-mechanism has been discussed for SiC{sub p}/Al composites' brazing joint. - Abstract: Aluminium matrix composites with high volume fractions of SiC particles, as the reinforcements, are potentially suitable materials for electronic packaging. These composites, due to their poor weldability, however, have very limited applications. The microstructure and shear strengths of the bonds made in 55 vol.% SiC{sub p}/A356 composite, using an aluminium based filler alloy containing Cu, Si, Mg and Ni, were investigated in this paper. The brazing temperature had a clear effect on the bond integrity, and the samples brazed at 560 Degree-Sign C demonstrated good bonding between the filler alloy and the SiC particles. The maximum shear strength achieved in this work was 102 MPa.

  1. Termodynamics of the production of zirconium-aluminium alloys by metal-thermal reduction of zirconium tetrafluoride

    International Nuclear Information System (INIS)

    Reactions of aluminium- and calcium-thermal reduction of zirconium tetrafluoride with the formation of zirconium aluminides melting congruently and eutectics of the Zr-Al system have been analyzed thermodynamically. It has been assumed that it is possible to obtain alloy ingots of the eutectic composition containing 11 mass.% of aluminium and intermetallides of the composition of Zr4Al3 and ZrAl2 by the method of calcium-thermal reduction of zirconium tetrafluoride without preliminary heating of the charge. Presented are the advantages of the proposed processes over the known method of zirconium alloy production by alumothermal reduction of K2ZrF6 in the melt of the reducing agent

  2. Wear Performance and Hardness Property Of A356.1 Aluminium Alloy Reinforced with Zirconium Oxide Nano Particle

    Directory of Open Access Journals (Sweden)

    Girisha.K.B1 ,

    2014-06-01

    Full Text Available Aluminium alloy reinforced with Nano-sized ZrO2 particles are widely used for high performance applications such as automotive, military, aerospace, and electricity industries because of their improved physical and mechanical properties. In this research, Zirconium Oxide (ZrO2 Nano particles were synthesized by Solution Combustion Synthesis process. The Nano particles were characterized by Powder X-ray diffraction (PXRD and TEM. A356.1 Aluminium alloy was reinforced with 0.5, 1.0, 1.5 and 2.0 Wt.% of the Synthesized Zirconium Oxide Nanoparticle via stir casting Technique. The composites were then characterized by scanning electron microscopy (SEM . Hardness and Wear tests were carried out at Varying Wt. % ratios with varying Conditions of Speed, Load and Time. The results reveal that the Nano Metal Matrix Composite (NMMC’s containing 2.0 Wt.% reinforcement particle has improved mechanical properties.

  3. Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754

    International Nuclear Information System (INIS)

    The aluminium alloy AA5754 is used for many technical applications. In this work, the accumulative roll bonding process is applied to this alloy in order to investigate the potential of an ultrafine-grained structure on the mechanical properties of this Al-Mg alloy. Sheets from AA5754 (AlMg3) were successfully processed by accumulative roll bonding in order to obtain an ultrafine-grained microstructure. The ARB process was performed at 230 0C or 250 0C up to 7 or 8 cycles respectively. Thus the grain size decreased from 10 ?m (initial state) to approximately 80 nm (ultrafine-grained state, normal direction). The microstructural evolution and the mechanical properties have been investigated by means of scanning electron microscopy, hardness measurements and tensile testing. After one ARB cycle the samples showed an increase in hardness by a factor of almost 2 in comparison to the as-received material. Further processing causes a linear increase of hardness with each additional cycle. Yield strength and tensile strength of the roll bonded specimens are highly increased in comparison to the as-received samples whereas the ductility declined. A considerable increase in ductility is obtained by heat treatment of the ARB specimens at 250 0C, but on the expense of a moderate decreased strength. The deformation behaviour is also influenced by the ultrafine-grained structure. The occurrence of the Portevin-Le Chatelier effect is manifested by vin-Le Chatelier effect is manifested by serrated stress-strain curves. The amplitude of serrations increases with increasing number of ARB cycles but can be reduced by the appliance of a higher strain rate. Lueders strain only occurs at the as-received, i.e. not strained, samples.

  4. Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754

    Science.gov (United States)

    Hausöl, T.; Höppel, H. W.; Göken, M.

    2010-07-01

    The aluminium alloy AA5754 is used for many technical applications. In this work, the accumulative roll bonding process is applied to this alloy in order to investigate the potential of an ultrafine-grained structure on the mechanical properties of this Al-Mg alloy. Sheets from AA5754 (AlMg3) were successfully processed by accumulative roll bonding in order to obtain an ultrafine-grained microstructure. The ARB process was performed at 230 °C or 250 °C up to 7 or 8 cycles respectively. Thus the grain size decreased from 10 ?m (initial state) to approximately 80 nm (ultrafine-grained state, normal direction). The microstructural evolution and the mechanical properties have been investigated by means of scanning electron microscopy, hardness measurements and tensile testing. After one ARB cycle the samples showed an increase in hardness by a factor of almost 2 in comparison to the as-received material. Further processing causes a linear increase of hardness with each additional cycle. Yield strength and tensile strength of the roll bonded specimens are highly increased in comparison to the as-received samples whereas the ductility declined. A considerable increase in ductility is obtained by heat treatment of the ARB specimens at 250 °C, but on the expense of a moderate decreased strength. The deformation behaviour is also influenced by the ultrafine-grained structure. The occurrence of the Portevin-Le Chatelier effect is manifested by serrated stress-strain curves. The amplitude of serrations increases with increasing number of ARB cycles but can be reduced by the appliance of a higher strain rate. Lüders strain only occurs at the as-received, i.e. not strained, samples.

  5. Effect of Friction Stir Welding on Mechanical Properties of Dissimilar Aluminium Aa6061 and Aa2014 Alloy Joints

    OpenAIRE

    Purushotham, P.

    2014-01-01

    In present study, Dissimilar Friction Stir Butt Welds made of 2014 and 6061 Aluminium alloys were performed with various welding parameter. The present study deals with the influence of Square Profile Pin on Friction Stir Welded joint. FSW parameter such as Tool Rotational Speed, Welding Speed and Axial Force plays a significant role in the assessment of mechanical properties. Using ANOVA and Signal to Noise ratio, influence of FSW process parameters is evaluated and optimum w...

  6. Quench induced residual stress prediction in heat treatable 7xxx aluminium alloy thick plates using Gleeble interrupted quench tests.

    OpenAIRE

    Chobaut, Nicolas; Carron, Denis; Arsène, Sylvie; Schloth, Patrick; Drezet, Jean-Marie

    2015-01-01

    In this paper, a simple but realistic approach is presented to predict the as-quenched residual stress distribution in thick 7xxx aluminium alloy plates. Instead of modelling precipitation that occurs during quenching, a thermo-mechanical model is used whose parameters are identified using a limited number of tensile tests achieved after representative interrupted cooling paths in a Gleeble machine. The material behaviour law accounts for recovery at high temperature in a simple way and negle...

  7. Probabilistic thermal-mechanical fatigue criterion for lost foam casting aluminium alloys based on 2D/3D porosities distribution

    Directory of Open Access Journals (Sweden)

    Szmytka F.

    2014-06-01

    Full Text Available A thermal-mechanical fatigue criterion is proposed to assess the lifetime of aluminium alloys produced by a lost foam casting process. It is based on the observed size distribution of pores sizes which are considered as critical zones for cracks initiation and gives reliable results when both pores sizes are identified from X-ray tomography and mean stresses are taken into account. Lifetime probabilities are finally successfully compared with experimental results.

  8. Comparative Study of Aluminium Alloy Plate AA2014/7075 under the Effect of Butt Welding Process

    OpenAIRE

    Rajasuthan, K.; , S.Raja2

    2014-01-01

    Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA2014/7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are ta...

  9. Effects of strain rate on the characteristics of PLC deformation bands for AA5083-H116 aluminium alloy

    OpenAIRE

    A. Benallal; Berstad, Torod; Borvik, Tore; Hopperstad, Odd Sture; Nogueira de Codes, Rodrigo

    2009-01-01

    Abstract An experimental, theoretical and numerical investigation of the Portevin-Le Chatelier (PLC) effect in the aluminium alloy AA5083-H116 is undertaken in this paper. Five different tests at different overall strain rates are carried out on smooth flat specimens in order to exhibit the effects of strain rate on the characteristics of the deformation bands and their propagation. Both digital image correlation and digital infrared thermography are used to capture and characteriz...

  10. Investigation of photocatalytic activity of titanium dioxide coating deposited on aluminium alloy substrate by plasma technique

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Soyama, Juliano

    2011-01-01

    Nowadays, there is an increased need for functionalized surfaces with self-cleaning and antibacterial properties. Titanium dioxide (TiO2) in the anatase crystalline structure is one of the most powerful photocatalytic materials available today, which can provide above functionalities. The photocatalytic process is initiated by UV-light in TiO2 which creates electron-/hole pairs in the conduction band (CB) and valence band (VB) of TiO2, respectively. The electron/hole pairs generated have sufficient energy to cause reduction and oxidation on its surface providing the self-cleaning effect. Literature consists of large number of publications on titanium dioxide coating for self-cleaning applications, with glass as the main substrate. Only little work is available on TiO2 coating of metallic alloys used for engineering applications. Engineering materials, such as light-weight aluminium and steel have wide spread technological applications, where a combination of self-cleaning properties has a huge business potential. The results presented in this paper demonstrate superior photocatalytic properties of TiO2 coated aluminium compared to nano-scale TiO2 coating on glass substrate. The thickness of the coating strongly influences the photocatalytic properties. In general, the photocatalytic activity increased with thickness. Quantification of images scanned with Atomic Force Microscope (AFM) revealed that there is a linear relationship between the thickness of the coating and the average cell size of the crystals. Furthermore, it manifested that the surface area of the coating increased linearly with crystal size. The optical measurements demonstrated that the ability of the coating to absorb light was depended on the thickness of the coating. As the coating became thicker, the absorption increased up to a certain thickness where a saturation limit was reached. Overall, the results from decomposition studies and electrochemical measurements indicated that the thickness of the coating has a profound influence on the photocatalytic properties.

  11. Plastic behaviour and microstructure characterization high manganese aluminium alloyed steel for the automotive industry

    Directory of Open Access Journals (Sweden)

    D. Kuc

    2012-03-01

    Full Text Available Purpose: Automotive industry constantly demands high-strength steels which are characterized by the energy absorption possibilities during a collision. Such materials may, in the future, replace the currently used conventional steels. The groups of steels which meet these criteria are the austenitic steels and austenitic-ferritic steels with high manganese content (15-30% and high aluminium content (1-9%. Design/methodology/approach: Susceptibility of steel to cracking at high temperatures was tested on Gleeble 3800 simulator: zero resistance temperature was determined (TZW, zero plasticity temperature was determined (TZP, plasticity reversal temperature was determined (TNP. Research was completed by determination of steel plasticity and stress applying in next stage the deformation of samples in temperature from 850 to 1175°C. This temperature range corresponding with the field of parameters of plastic processing. For samples after tension the ultimate tensile strength was determined (Rm together with contraction (Z. Character of fractures of stretched samples was tested with the use of scanning microscope Hitachi S-4200.Findings: The tests show that the tested steel is characterised by relatively lower temperatures in comparison with low-alloyed steels. Tested steel has high plasticity in temperature wear to temperature of plastic processing 1150-800°C.Practical implications: The obtained steel is characterised by beneficial properties which outbalance the austenitic steels type TWIP and may be applied in vehicle construction on elements connected with safety.Originality/value: Conducted simulation will be helpful by elaboration of technology of continuous casting and the choice of the right parameters for plastic processing of high-manganese steel with aluminium.

  12. Aluminium EN AC-AlSi12 alloy matrix composite materials reinforced by Al2O3 porous preforms

    Directory of Open Access Journals (Sweden)

    A. Nagel

    2007-10-01

    Full Text Available Purpose: The purpose of this work is to elaborate the method of manufacturing of composite materials based on porous ceramic preforms infiltrated by eutectic aluminium alloy.Design/methodology/approach: The material for investigations was fabricated by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC – AlSi12 was use as a matrix while as reinforcement were used ceramic preforms fabricated by sintering of Al2O3 Alcoa CL 2500 powder with addition of pore forming agents as carbon fibres Sigrafil C10 M250 UNS manufactured by SGL Carbon Group company. The observations of the structure were made on the light microscope and in the scanning electron microscope. EDS and XRD analysis of obtained composite materials have been also made.Findings: The developed technology of manufacturing of composite materials with the pore ceramic Al2O3 infiltration ensures expected structure and can be used in practice.Practical implications: The composite materials made by the developed method can find application as the alternative material for elements fabricated from light metal matrix composite material reinforced with ceramic fibrous preforms.Originality/value: The obtained results show the possibility of manufacturing the composite materials by the pressure infiltration method of porous sintered framework based on the ceramic particles with liquid aluminium alloy.

  13. Comparative Study of Aluminium Alloy Plate AA2014/7075 under the Effect of Butt Welding Process

    Directory of Open Access Journals (Sweden)

    K.Rajasuthan*

    2014-01-01

    Full Text Available Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA2014/7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are taken into account through boundary conditions for the outward heat flux. Linear FE transient thermal analysis is performed using surface heat source model with Gaussian distribution to compute highest temperature in AA2014 plates. The objective of this project is to simulate the welding process by using the finite element method. After the model is built and verified, the main objective of this project is to study the effects of varying the welding process parameters on the thermo-mechanical responses. In addition to that, the aim of this research is also to find a relationship between welding parameters and the responses of single pass butt welding are evaluated through the finite element analysis of Aluminium Alloy AA2014 and AA7075. The study of this paper covers the Comparative Study of Aluminium Alloy Plate 2014/7075 under the effect of Butt welding process by varying heat input, welding speed on the thermo-mechanical responses of the weldment after cooling down to room temperature.

  14. Studies of the subsurface zone created in aluminium and its alloys by means of positron annihilation and complementary methods

    International Nuclear Information System (INIS)

    There are presented the results of the studies of the subsurface zone created in aluminium and its alloys during sliding or other surface modification treatments. The application of the positron annihilation techniques due to their high sensitivity to crystal lattice defects enabled to determine defects profiles in the subsurface zone. The positron annihilation studies were correlated with other conventional measurements applied in tribology, i.e. microhardness measurements, scanning electron microscopy, X-ray diffraction and in a special case stress distribution calculated theoretically. It was shown that the positron annihilation spectroscopy is a useful tool for profiling of the subsurface zone created during sliding even for light metals their alloys and composites. The total range of the subsurface zone detected by the positron annihilation extends from 50 ?m to 450 ?m depending on the material studied and surface modification treatment. Additionally, the type of the main defects can be determined. The studies of the pure aluminium samples after dry sliding enabled to find the defect concentration of vacancy type in the depth less then 1 ?m and to correlate its value with the size of crystallites. It supports the conclusion on recovery processes taking place in this layer. There was made the attempt to apply the Doppler broadening coincidence spectroscopy to the studies of aluminium alloy and composite. In view of the interdisciplinary character the present thesis enclose also the review of the basic issues of tribology, measurement methods applied to the subsurface zone studies and positron annihilation experimental techniques. (author)

  15. Influence of the corrosive medium and applied load direction on the stress corrosion cracking behaviour of 7075 aluminium alloy

    International Nuclear Information System (INIS)

    The goal of this work is to prove the validity of using synthetic sea water as an alternative method instead of the NaCl solution used in stress corrosion crack growth tests in aluminium alloys, according to ASTM G 44. Several samples of 7075 alloy have been tested in different conditions and directions in both environments, which can be considered as equivalent. Only the samples tested in thickness direction have shown crack growth during the test. The use of sea water entails a great advantage in practice, by less superficial alteration, and less therefore a much more reliable measure of the crack. (Author) 8 refs

  16. Age-hardening characteristics of ?-alumina fibre reinforced aluminium-silicon LM-13 alloy metal matrix composites

    OpenAIRE

    Akbulut, H.; Durman, M.; Yilmaz, F.

    1993-01-01

    Metal Matrix Composites (MMCs) with an aluminium-silicon based LM-13 alloy and short-staple Saffil (?-alumina) fibres with volume fractions of 0.10, 0.15, 0.20, 0.25 and 0.30 have been produced using a pressure liquid infiltration process. The standard T6 heat treatment procedure was applied to both the unreinforced matrix alloy and the composites, and the effect of the fibres on the age-hardening characteristics of the composites has been investigated by means of hardness measurements.

  17. The Effects of Zinc Additions on the Corrosion Susceptibility of Aluminium Alloys in Various Tetraoxosulphate (VI Acid Environments

    Directory of Open Access Journals (Sweden)

    C.E. Ekuma

    2007-01-01

    Full Text Available The influence of zinc additions on the corrosion behaviour of aluminium alloys in H2SO4 solution of varying concentrations has been investigated. Aluminium-zinc alloys of 1.0, 2.0, 2.5, 3.5 and 4.0% zinc by weight were cast and machined to cuboidal test coupons of initial surface area averaging 12.71 cm2. The coupons were then weighed and immersed into beakers containing 0.5 M and 1.0 M H2SO4 solutions. The set-ups were allowed to stand for six days with a set withdrawn daily for corrosion rate characterization using standard procedures. The results showed that although, the normal corrosion rate profile (for passivating metals of an initial steep rise, then a progressive decline was observed in all the media as the fraction of the solute in the alloy increased, there was severity of attack on the 2.5% Zn alloy. It is concluded that the severity of attack on the 2.5% Zn alloy is due to increased grain boundary concentration possibly implying a maximum solid solubility (solvus line in Al-Zn binary systems within this range.

  18. Sintering behaviour of Alumix 321 and 6061 aluminium alloys; Sinterizacion de las aleaciones Alumix 321 y 6061

    Energy Technology Data Exchange (ETDEWEB)

    Romano, P.; Fogagnolo, J. B.; Garcia, A.; Ruiz-Navas, E. M.

    2005-07-01

    The sintering behaviour of two aluminium alloys, Alumix 321 and 6061, was studied in this paper. Both have a similar Mg, Cu and Si contents, but have been obtained by different methods. the Alumix 321 alloy is produced by mixing the initial elements as powders and the 6061 is obtained by water atomization. The work carried out includes the study of the green properties, the determination of the compressibility and green strength curves as well as the microstructural characterization of the powders. Thermal analyses (DTAs and Dilatometries) were performed in order to study the behaviour of both alloys with temperature. furthermore, different sintering temperatures were studied by characterizing the mechanical properties of the sintered materials. It can be concluded that the 6061 alloys has better properties than the Alumix 321, when both were sintered at 600 degree centigree. (Author) 27 refs.

  19. Processing and characterization of aluminium alloys or composites exhibiting low-temperature or high-rate superplasticity

    International Nuclear Information System (INIS)

    Wide applications of superplastic forming still face several problems, one is the high temperature that promotes grain growth, another is the low forming rate that makes economically inefficient. The current study is intended to develop a series of fabrication and thermomechanical processing, so as to result in materials possessing either low temperature superplasticity (LTSP) or high rate superplasticity (HRSP). The former has been achieved in the cast Al alloys, while the latter was accomplished in powder-metallurgy aluminium matrix composites. The aluminium alloys, after special thermomechanical processes, exhibited LTSP from 300 to 450 degree C with elongations varying from 300 to 700 %. The LTSP sheets after 700 % elongation at 350 degree C still possessed fine grains 3.7 ?m size and narrow surface solute depletion zones 11 ?m in with, resulting in a post-SP T6 strength of 500 MPa, significantly higher than that of the HTSP superplasticity alloys tested at 525 degree C or above. Meanwhile, it was found that LTSP materials may be transferred into HTSP materials simply by adding a preloading at 300-400 degree C for a small amount of work. As for the endeavor in making HRSP materials, 2024Al/SiC, 6061Al/SiC and Al/Al3Ti systems processed by powder metallurgy or mechanical alloying methods are under investigation. The average sizes of the reinforcing SiC or A13Ti particles, as well as the grain size are all around 1 ?m. The aluminium composites have exhibited HRSP at 525-620 degree C and 10-2-10-1 s-l, with elongations varying from 150 to 350 %. This ultimate goal is to produce an alloy or composite exhibiting low temperature and high strain rate superplasticity (LT and HRSP). (author)

  20. EVALUATION OF PARAMETERS OF FRICTION STIR WELDING FOR ALUMINIUM AA6351 ALLOY

    Directory of Open Access Journals (Sweden)

    AHMED KHALID HUSSAIN

    2010-10-01

    Full Text Available Friction Stir Welding (FSW is a solid state welding process in which the relative motion between the tool and the work piece produces heat which makes the material of two edges being joined by plastic atomicdiffusion. This method relies on the direct conversion of mechanical energy to thermal energy to form the weld without the application of heat from conventional source. The rotational speed of the tools, the axial pressure and welding speed and the (weld time are the principal variables that are controlled in order to provide the necessary combination of heat and pressure to form the weld. These parameters are adjusted so that the interface is heated into the plastic temperature range (plastic state where welding can take place. During the last stage of welding process, atomic diffusion occurs while the interfaces are in contact, allowing metallurgical bond to form between the two materials. The functional behaviour of the weldments is substantially determined by the nature of the weld strength characterized by the tensile strength, metallurgical behavior, surface roughness, weld hardness and micro hardness. In this project an attempt is made to determine and evaluate the influence of the process parameters of FSW on the weldments. The Vickers hardness, tensile strength and radiography are considered for investigation by varying tool speed, tool feed and maintaining onstant depth of penetration of weld. Experiments were conducted on AA6351 Aluminium alloy in a CNC Vertical Machining Centre. Theoutput factors are measured in UTM, Vickers hardness tester and Radiography equipment. Results show strong relation and robust comparison between the weldment strength and process parameters. Hence FSW process variable data base is to be developed for wide variety of metals and alloys for selection of optimum process parameters for efficient weld.

  1. The effect of molybdenum ion implantation on the general and pitting corrosion behaviour of pure aluminium and a high strength aluminium alloy

    International Nuclear Information System (INIS)

    The effect of Ar and Mo ion implantations on the corrosion behaviour of pure Al and a high strength aluminium alloy (7075-T6) has been investigated in Cl--free and Cl--containing sulphate solutions. In Cl-free environments, Mo implantation markedly affects the general corrosion behaviour of both the pure metal and the alloy. Ar implantation, on the other hand, has no permanent effect on the potentiodynamic polarization behaviour of pure Al but does alter somewhat the polarization characteristics of 7075-T6. In Cl--containing environments, Mo implantation significantly improves the resistance of pure Al to pitting corrosion, and increases the breakdown potential by about 200 mV. A similar, though less marked effect is observed with the alloy. Ar implantation has no major effect on the behaviour of either the pure metal or 7075-T6 in Cl--containing environments. On the basis of Rutherford backscattering and potential-time measurements it is suggested that the beneficial effect of Mo may be due to either the incorporation of Mo in the passive film or to dissolution and reprecipitation of some Mo-containing species on the passive film. (author)

  2. Microstructure and high temperature deformation of an ultra-fine grained ECAP AA7075 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Malek, Premysl; Turba, Krystof; Cieslar, Miroslav; Harcuba, Petr [Charles Univ., Prague (Czech Republic). Dept. of Physics of Materials

    2013-01-15

    An AA 7075 aluminium alloy with an ultra-fine grained structure was prepared through equal channel angular pressing (ECAP) at pressing temperatures T ECAP of 120, 170, and 220 C. A decrease in T{sub ECAP} from 220 to 120 C was found to lead to a more pronounced refinement of the microstructure and to worse stability of the microstructure - the onset of grain coarsening was displaced to lower temperatures. The material pressed with the highest T{sub ECAP} exhibited superplastic behaviour at temperatures close to 400 C and grain boundary sliding was identified as the dominant operating deformation mechanism. The materials prepared with both of the lower T{sub ECAP} exhibited only enhanced ductility of about 200%, however this behaviour was observed at temperatures as low as 200 C. It was found that this 'low temperature superplasticity' resulted from a combined operation of grain boundary sliding at selected grain boundaries and glide of lattice dislocations. (orig.)

  3. Effects of heat treatments on the microstructure and mechanical properties of a 6061 aluminium alloy

    International Nuclear Information System (INIS)

    Research highlights: ? Description of the mechanical behavior of AA6061-T6 at RT after various thermal histories. ? A fast-heating device has been designed to reproduce those thermal histories on tensile specimens. ? The thermal loadings are representative of the temperature change observed in the HAZ during welding. ? The variation of mechanical properties is the result of metallurgical evolution observed by TEM. ? The yield stress at RT decreases with the maximum temperature reached during the thermal cycle. - Abstract: This paper describes the mechanical behavior of the 6061-T6 aluminium alloy at room temperature for various previous thermal histories representative of an electron beam welding. A fast-heating device has been designed to control and apply thermal loadings on tensile specimens. Tensile tests show that the yield stress at ambient temperature decreases if the maximum temperature reached increases or if the heating rate decreases. This variation of the mechanical properties is the result of microstructural changes which have been observed by Transmission Electron Microscopy (TEM).

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

    Science.gov (United States)

    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.

  5. Electrochemical preparation of aluminium-nickel alloys by under-potential deposition in molten fluorides

    International Nuclear Information System (INIS)

    The electrochemical behaviour of AlF3 was investigated in LiF-CaF2 medium first with inert tungsten and then with reactive nickel electrodes. Cyclic voltammetry, square-wave voltammetry and chronopotentiometry indicated that the reduction of Al(III) in Al(0) is a single-step process exchanging three electrons: Al(III) + 3e- = Al The electrochemical reduction is controlled by the diffusion of AlF3 in the solution. On a nickel electrode, a depolarisation effect for Al(III) reduction was observed in cyclic voltammetry due to the formation of Al-Ni alloys when aluminium ions react with the nickel substrate. Galvanostatic and potentiostatic electrolyses on a nickel electrode led to the formation of four nickel aluminides characterised by SEM: AlNi3, AlNi, Al3Ni2 and Al3Ni. Layers with a uniform composition of AlNi3, AlNi and Al3Ni2 were prepared by varying the electrolysis potential, the current density and duration of intermetallic diffusion

  6. Prepare and Formation Mechanism of the Zirconia Coating on Aluminium Alloy by Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    XIN Shi-Gang,ZHAO Rong-Gen,DU Hui,SONG Li-Xin

    2009-01-01

    Full Text Available Zirconia coating was produced on aluminium alloy by plasma electrolytic oxidation (PEO. The alkaline electrolyte containing Zr(OHª4 powders was used. The composition and structure of the coating were investigated by XRD, EPMA. The results show that the coating consists of ª«t-ZrO2, ª«m-ZrO2, ª«¦?/SUB>-Al2O3 and ª«¦|/EM>-Al2O3. ª«t-ZrOª2 is the main phase and distributes in outer layer of the coating, however, ª«¦?/EM>-Al2O3 appears in inner layer of the coating. Many micro-particles appear on the coating surface with dimension of ª©1£2¦?ªª. In the process of plasma electrolytic oxidation, Zr(OHª4 powders move and deposite on the mouth of plasma discharge channel under the effect of electric field force, then it is transformed to ZrOª2 by the high temperature of plasma discharge.

  7. Experimental and numerical evaluation of friction stir welds of AA6061-T6 aluminium alloy

    Directory of Open Access Journals (Sweden)

    P. Prasanna

    2010-06-01

    Full Text Available Friction stir welding is a relatively new joining process, which involves the joining of metals without fusion or filler materials. The amount of the heat conducted into the work piece dictates a successful process which is defined by the quality, shape and microstructure of the processed zone, as well as the residual stress and the distortion of the work piece. The amount of the heat gone to the tool dictates the life of the tool and the capability of the tool to produce a good processed zone. Hence, understanding the heat transfer aspect of the friction stir welding is extremely important for improving the process. Many research works were carried out to simulate the friction stir welding using various soft wares to determine the temperature distribution for a given set of welding conditions. Very few attempted to determine the maximum temperature by varying the input parameters using ANSYS. The objective of this research is to develop a finite element simulation of friction stir welding of AA6061-T6 Aluminium alloy. Trend line equations are developed for Thermal conductivity, specific heat and density to know the relationship of these factors with peak temperature. Tensile and hardness values for the welded specimens are found for different rotational speed and feed. Variation of temperature with input parameters is also observed. The simulation model is tested with experimental results. The results of the simulation are in good agreement with that of experimental results.

  8. Friction stir processing of a Zr-modified 2014 aluminium alloy

    International Nuclear Information System (INIS)

    The mechanical and microstructural properties of a Zr-modified 2014 aluminium alloy resulting from friction stir processing were analysed. The sheets were processed parallel to the extrusion direction, the tensile mechanical properties were evaluated at room temperature in transverse and longitudinal direction respect to the processing one. Tensile tests were also performed at higher temperatures and different strain rates in the nugget zone, in order to analyse the superplastic properties of the recrystallized material and to observe the differences with the parent materials as a function of the strong grain refinement due to the friction stir process. The high temperature behaviour of the material was studied, in the parallel direction, by means of tensile tests in the temperature and strain rate ranges of 400-500 deg. C and 10-2 to 10-4 s-1, respectively. Scanning electron microscopy (field-emission gun) examinations were also carried out to investigate more closely the fracture surfaces of the specimens tested at different temperatures and strain rates. The dynamic recrystallized structure of the material was observed by employing optical and electron microscopy. The room temperature and high temperature tensile properties of the heavily refined structure resulted optimal for superplastic deformation thanks to very high levels of strain to fracture and strain-rate sensitivity exhibited at high strain rate levels (10-2 s-2 s-1)

  9. Thermal Analysis on Butt Welded Aluminium Alloy AA7075 Plate Using FEM

    Directory of Open Access Journals (Sweden)

    M. Pal Pandi

    2014-03-01

    Full Text Available Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are taken into account through boundary conditions for the outward heat flux. Linear FE transient thermal analysis is performed using surface heat source model with Gaussian distribution to compute highest temperature in AA7075 plates. The objective of this project is to simulate the welding process by using the finite element method. After the model is built and verified, the main objective of this project is to study the effects of varying the welding process parameters on the thermo-mechanical responses. In addition to that, the aim of this research is also to find a relationship between welding parameters and the responses of single pass butt welding are evaluated through the finite element analysis. The study of this paper covers the effects of varying heat input, welding speed on the thermo-mechanical responses of the weldment after cooling down to room temperature.

  10. Effect of friction stir lap welding conditions on joint strength of aluminium alloy 6060

    International Nuclear Information System (INIS)

    Strength of lap joints made by friction stir welding (FSW) depends strongly on how material flows forming the weld nugget zone during FSW and also on how the joint is loaded during testing. Understanding of this processing-property relationship is currently inadequate. In this study, the effects of pin length, welding speed and rotation rate on weld strength using aluminium alloy 6060 were investigated. It has been found that the pin length needed to be slightly greater than the thickness of the sheet for an adequate joint to be established. However, further increase in pin length did not benefit the joint strength. The major factor affecting joint strength has been found to be the rotation speed. An increase in rotation speed resulted in lowering the joint strength. Various modes of fracture have been observed and these modes relate to the degree of hooking and softening. Explanation of how the speed values relate to heat input and material flow and then to the joint strength is given.

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

    Science.gov (United States)

    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.

  12. WEIGHT LOSS CORROSION STUDIES OF ALUMINIUM-7075 ALLOY REINFORCED WITH SILICON CARBIDE PARTICULATES COMPOSITES IN ACID CHLORIDE MEDIUM

    Directory of Open Access Journals (Sweden)

    Nataraja.G

    2015-04-01

    Full Text Available The aim of the research work to investigate the corrosion behaviour of Silicon Carbide(SiC reinforced aluminium 7075 metalmatrix composites (MMCs in acid chloride solution using weight loss method. The composites are manufactured by liquid metallurgy technique using vortex method. Aluminium 7075 / SiC MMCs containing 2, 4 and 6 weight percentage of SiC particulates are casted. The corrosion characteristics of Aluminium 7075 /SiCcomposite and the unreinforced alloy were experimentally assessed. The corrosion test was carried out at different concentrations of 0.025M, 0.05M and 0.1 M solutions for different exposure time. The results indicated that corrosion rate of metal matrix composites was lower than that of matrix material Al 7075 under the corrosive atmosphere irrespective of exposure time and concentration of corrodent. Aluminium 7075 / SiC composite become more corrosion resistant as the SiC content is increased. This is because of the formation of stable oxide layer over the specimens.

  13. Experimental investigations of visco-plastic properties of the aluminium and tungsten alloys used in KE projectiles

    Directory of Open Access Journals (Sweden)

    Magier M.

    2012-08-01

    Full Text Available The main aim of studies on dynamic behaviour of construction materials at high strain rates is to determine the variation of mechanical properties (strength, plasticity in function of the strain rate and temperature. On the basis of results of dynamic tests on the properties of constructional materials the constitutive models are formulated to create numerical codes applied to solve constructional problems with computer simulation methods. In the case of military applications connected with the phenomena of gunshot and terminal ballistics it’s particularly important to develop a model of strength and armour penetration with KE projectile founded on reliable results of dynamic experiments and constituting the base for further analyses and optimization of projectile designs in order to achieve required penetration depth. Static and dynamic results of strength investigations of the EN AW-7012 aluminium alloy (sabot and tungsten alloy (penetrator are discussed in this paper. Static testing was carried out with the INSTRON testing machine. Dynamic tests have been conducted using the split Hopkinson pressure bars technique at strain rates up to 1,2 ? 104s?1 (for aluminium alloy and 6 ? 103s?1 (for tungsten alloy.

  14. Extrusion of powder-metallurgically prepared high-silicon aluminium alloys. Pt. 1; Strangpressen pulvermetallurgisch hergestellter, hochsiliziumhaltiger Aluminiumlegierungen. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, K.B.; Winsemann, U. [Technische Univ. Berlin (Germany). Forschungszentrum Strangpressen

    1999-04-01

    For applications in automotive engineering, aluminium alloys with a high silicon content have been developed, which can be made in various ways. For example, cylinder liners are made from a spray-compacted pre-material. For the highest strength requirements, there are alloys made from atomised alloy powder. This material can be completely compacted by extrusion. The present article describes experimental results obtained in the context of a research project on `Optimising the extrusion and heating conditions for the extrusion of powder-metallurgically prepared aluminium alloys` at the Extrusion Research Centre (Forschungszentrum Strangpressen, FZS) of the Technical University, Berlin. (orig.) [Deutsch] Fuer Automobilanwendungen sind Aluminiumlegierungen mit hohem Siliziumgehalt entwickelt worden, die auf unterschiedliche Arten hergestellt werden. Beispielsweise werden Zylinderlaufbuchsen aus spruehkompaktiertem Vormaterial gefertigt. Fuer hoechste Anforderungen an die Festigkeitseigenschaften bietet sich die Herstellung aus verduestem Legierungspulver an. Die vollstaendige Kompaktierung dieses Werkstoffs kann mittels Strangpressen erfolgen. Nachfolgend werden Versuchsergebnisse beschrieben, die im Rahmen des Forschungsvorhabens `Optimierung der Press- und Erwaermungsbedingungen fuer das Strangpressen pulvermetallurgisch hergestellter Aluminiumlegierungen` am Forschungszentrum Strangpressen (FZS) der Technischen Universitaet Berlin erarbeitet wurden. (orig.)

  15. Electrochemical etching of AA5083 aluminium alloy in trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ionic liquid

    International Nuclear Information System (INIS)

    Highlights: •Ionic liquids were employed in electrochemical pretreatment for AA5083 alloy. •Improved corrosion resistance was observed on the ionic liquid treated AA5083 alloy surface. •The improvement in corrosion was found to be due to an electrochemical etching process similar to acid etching. -- Abstract: Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P6,6,6,14][NTf2]) ionic liquid is shown to react with AA5083 aluminium alloy under a two-step anodic polarisation, leading to partial passivation of the surface. Surface characterisation established that an electrochemical etching process had occurred, comparable to acid etching of aluminium. Energy dispersive X-ray spectroscopy (EDXS) and X-ray photoelectron spectroscopy (XPS) results indicated that magnesium de-alloyed from Mg2Si intermetallic particles and metal fluorides were deposited onto the remaining Mg2Si sites, leading to a decrease in the anodic corrosion kinetics (to one third of that of the control) as well as a 100 mV vs. SCE increase in the corrosion and pitting potentials

  16. Electrorefining of U-Pu-Zr-alloy fuel onto solid aluminium cathodes in molten LiCl-KCl

    International Nuclear Information System (INIS)

    An electrorefining process in molten chloride salts using solid aluminium cathodes is being developed at ITU to recover actinides (An) from the spent nuclear fuel. The maximum possible loading of aluminium electrodes with actinides was investigated during the electrorefining of U-Pu-Zr alloy in a LiCl-KCl eutectic at 450 C. Two different electrolytic techniques were applied during the experiment and almost 6000 C has been passed, corresponding to 3.7 g of deposited actinides. A very high capacity of aluminium to retain actinides has been proven as the average Al: An mass ratio was 1: 1.58 for galvanostatic and 1: 2.25 for potentiostatic mode. The obtained deposits were characterized by XRD and SEM-EDX analysis and alloys composed of (U,Pu)Al3 were detected. The influence of zirconium co-oxidation during the process was also investigated and the presence of dissolved Zr ions in the melt yielded a significant deterioration of the quality of the deposit. (orig.)

  17. Metal head - dependent HTC in sand casting simulation of aluminium alloys

    Directory of Open Access Journals (Sweden)

    G.S. Cellini

    2008-07-01

    Full Text Available Purpose: In order to obtain reliable sand casting products, it is essential that the temperature distribution within the alloy during cooling is accurately known at each point by FEM simulation. This requires a great precision in setting the Heat Transfer Coefficients (HTC at the boundaries. In particular for castings of big size, chills are frequently at different heights, so that remarkable differences arise from the metal head effect.Design/methodology/approach: An A356 alloy was cast and cooled. The castings were mono-directionally solidified in a experimental equipment modified to accept a controlled variable metal-head. HTC were evaluated in a side arm, where a chill end ensured a dominant unidirectional heat flow during cooling. At the end of a square horizontal channel, an aluminium chill of the same section and 60 mm in depth determined nearly one-dimensional cooling conditions.Findings: The evolution of heat transfer coefficient (HTC in the sand casting of A357 aluminum alloy against aluminum chills is evaluated with different metal heads in order to study the effect of pressure on the HTC. Inverse modeling techniques based on Beck’s analysis were used to determine the experimental evolution of HTC as a function of time, casting temperature and chill temperature. The HTC evolution at the casting-chill boundary is then described as a function of local parameters such as casting-chill interface pressure (as long as they are in contact and interface gap (when solidification shrinkage occurs and the casting detaches from the chill.Practical implications: Finally, the experiments are reconstructed by means of coupled thermal-stress numerical analyses and the predicted cooling curves are fitted to the experimental ones by adjusting model parameters. As a result, the best parameters for describing the HTC evolution are found, thus allowing to extrapolate any possible HTC behavior on chills at different heights for the same casting.Originality/value: Some transient interface pressure can develop between casting and chill, the effect being negligible in HTC evaluation with the aim to precisely predict the cooling evolution inside the casting.

  18. Mechanical Behaviour of Friction Stir Welding Joints of Aluminium alloy of AA6351 with AA6351 and AA6351 with AA5083

    Directory of Open Access Journals (Sweden)

    G.Gopala Krishna

    2014-04-01

    Full Text Available Modern structural application demands reduction in both the weight and as well as cost of the fabrication and production of materials. Aluminium alloys are the best choice for the reduction of weight, cost and replacing steels in many applications and Friction Stir Welding (FSW process efficient and cost effective process. FSW is solid state welding process in which material is not melted during welding process so it overcomes many welding defects compared to conventional fusion welding process which is initially used for low melting materials. This process is initially developed for low melting materials like Aluminium, Magnesium, Zinc but now process is useful for high melting materials like steel and also for composites materials. The present study describes the effect of FSW process involving butt joining of similar Aluminium alloy combinations of AA6351 with AA6351 and dissimilar Aluminium ally combinations of AA6351 with AA5083 on the tensile, hardness and impact behaviour.

  19. Nanocomposite of polypyrrole and alumina nanoparticles as a coating filler for the corrosion protection of aluminium alloy 2024-T3

    Science.gov (United States)

    Tallman, Dennis E.; Levine, Kirill L.; Siripirom, Chavanin; Gelling, Victoria G.; Bierwagen, Gordon P.; Croll, Stuart G.

    2008-06-01

    Aluminium (Al) alloys such as 2024-T3 are widely used in industry as low weight construction materials with excellent mechanical properties. Until recently corrosion protection of Al alloys was carried out with coatings containing hexavalent chromium (Cr 6+). However, Cr 6+ is a health and environmental hazard and has to be replaced. Intrinsically conducting polymer (ICP) technology is the promising alternative to chromate coating technology because of good corrosion protection properties of ICPs, their moderate cost and good environmental compatibility. In this paper we report successful attempt of making nanocomposite comprised of alumina nanoparticles modified by polypyrrole for the purpose of corrosion protection of Al alloy. Modified nanoparticles were used as coating filler. Coating was designated to perform as an active barrier to electrolyte diffusion. Properties of the coating were examined by adhesion test, electrochemical impedance spectroscopy, X-rays elemental analysis, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy.

  20. Nanocomposite of polypyrrole and alumina nanoparticles as a coating filler for the corrosion protection of aluminium alloy 2024-T3

    International Nuclear Information System (INIS)

    Aluminium (Al) alloys such as 2024-T3 are widely used in industry as low weight construction materials with excellent mechanical properties. Until recently corrosion protection of Al alloys was carried out with coatings containing hexavalent chromium (Cr6+). However, Cr6+ is a health and environmental hazard and has to be replaced. Intrinsically conducting polymer (ICP) technology is the promising alternative to chromate coating technology because of good corrosion protection properties of ICPs, their moderate cost and good environmental compatibility. In this paper we report successful attempt of making nanocomposite comprised of alumina nanoparticles modified by polypyrrole for the purpose of corrosion protection of Al alloy. Modified nanoparticles were used as coating filler. Coating was designated to perform as an active barrier to electrolyte diffusion. Properties of the coating were examined by adhesion test, electrochemical impedance spectroscopy, X-rays elemental analysis, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy

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

    Science.gov (United States)

    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. PMID:25063163

  2. Influence of friction stir welding process and tool parameters on strength properties of AA7075-T6 aluminium alloy joints

    International Nuclear Information System (INIS)

    The aircraft aluminium alloys generally present low weldability by traditional fusion welding process. The development of the friction stir welding has provided an alternative improved way of satisfactorily producing aluminium joints, in a faster and reliable manner. In this present work, the influence of process and tool parameters on tensile strength properties of AA7075-T6 joints produced by friction stir welding was analysed. Square butt joints were fabricated by varying process parameters and tool parameters. Strength properties of the joints were evaluated and correlated with the microstructure, microhardness of weld nugget. From this investigation it is found that the joint fabricated at a tool rotational speed of 1400 rpm, welding speed of 60 mm/min, axial force of 8 kN, using the tool with 15 mm shoulder diameter, 5 mm pin diameter, 45 HRc tool hardness yielded higher strength properties compared to other joints.

  3. Effect of tool profile and fatigue loading on the local hardness around scratches in clad and unclad aluminium alloy 2024

    International Nuclear Information System (INIS)

    Nanoindentation has been used to study the hardness changes produced by scratching of aluminium alloy AA2024, with and without a clad layer of pure aluminium. The hardness was mapped around scratches made with diamond tools of different profiles. One tool produced significant plastic damage with associated hardening at the scratch root, whilst the other produced a 'cleaner' cut with no hardening. The different behaviours are attributed to whether the tool makes the scratch by a 'cutting' or a 'ploughing' mechanism. The degree of plastic damage around the scratches has been correlated with peak broadening data obtained using synchrotron X-ray diffraction. There was no change observed in the local hardness around the scratch with fatigue loading.

  4. Effect of friction time on the properties of friction welded YSZ?alumina composite and 6061 aluminium alloy

    Directory of Open Access Journals (Sweden)

    Uday M. Basheer

    2012-03-01

    Full Text Available The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried out under different rotational speeds and friction times, while friction force (0.5 ton-force was kept constant. Scanning electron microscopy was used to characterize the interface of the joints structure. The experimental results showed that the friction time has a significant effect on joint structure and mechanical properties.

  5. Effect of Friction Stir Welding on Mechanical Properties of Dissimilar Aluminium Aa6061 and Aa2014 Alloy Joints

    Directory of Open Access Journals (Sweden)

    P. Purushotham*

    2014-04-01

    Full Text Available In present study, Dissimilar Friction Stir Butt Welds made of 2014 and 6061 Aluminium alloys were performed with various welding parameter. The present study deals with the influence of Square Profile Pin on Friction Stir Welded joint. FSW parameter such as Tool Rotational Speed, Welding Speed and Axial Force plays a significant role in the assessment of mechanical properties. Using ANOVA and Signal to Noise ratio, influence of FSW process parameters is evaluated and optimum welding condition for maximizing mechanical properties of the joint is determined. An Artificial Neural Network (ANN model was developed for the analysis and simulation of the correlation between the Friction Stir Welding (FSW parameters of aluminium (Al plates and mechanical properties and compared the experimental values with the ANN predicted values.

  6. Influência do superaquecimento nas variáveis térmicas de solidificação e na formação da microestrutura de ligas de alumínio Overheating influence on solidification - thermal variables and microstructure formation of aluminium alloy

    OpenAIRE

    Jean Robert Pereira Rodrigues; Tonnyfran Xavier de Araujo Sousa; Ricardo Batista de Andrade; Rezende Gomes dos Santos; Mírian de Lourdes Noronha Motta Mello

    2009-01-01

    O objetivo do trabalho é o desenvolvimento de uma análise comparativa do processo de solidificação da liga de alumínio com diferentes taxas de superaquecimento. Os principais parâmetros de solidificação foram determinados experimentalmente afetados pelo grau de superaquecimento e sua influência na formação da microestrutura. Foi escolhida a liga de AA5052 contendo 3% de magnésio pelo seu interesse comercial. A liga foi vazada com três diferentes graus de superaquecimento, em um d...

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

    Science.gov (United States)

    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 ?m in thickness and an Al-Cu alloy of 30 ?m 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.

  8. Effect of Welding Parameters on Metallurgical Properties of Friction Stir Welded Aluminium Alloy 6063-O

    Directory of Open Access Journals (Sweden)

    K. Balachandar

    2012-01-01

    Full Text Available The effect of process parameters on metallurgical properties of friction stir welded aluminium alloy 6063-O was analysed in the present study. Samples were friction stir welded under tool rotational speed of 600, 800 and 1200 rpm and traversing speed of 0.6, 0.9 and 1.2 mm sec-1, with an axial load of 8000 kg constant for all trials and the process parameters were optimized by using Taguchi orthogonal array. Optical microstructure analysis were carried out to define the metallurgical properties at various zones of friction stir welded samples (Unaffected Base Material, Heat Affected Zone, Thermo Mechanically Affected Zone and Weld Nugget Zone and scanning electron microscopy analysis (SEM was carried out to determine the material flow path at the heat affected zone (HAZ and weld nugget zone (WN of friction stir welded samples. In present work two sets of experiments were carried out on AA 6063-O one with silicon carbide powder and without silicon carbide powder. Tool used for the FSW process is high carbon steel D3 (Heat treated 58-60 HRC, the SiC powders were inserted along the breadth of the plates by making a drill of 1 mm to a depth of 15 mm. Micro hardness survey was done across the weld regions using vickers hardness test. Correlation of micro hardness tests and metallurgical properties of the friction stir weldments were studied by optical microscope analysis, scanning electron microscopy analysis and the samples were chosen for (SEM using grey relational analysis (GRA. It was observed that the sample 9 with SiC powders, welded with a traverse speed of 1.2 mm sec-1, tool speed of 1200 rpm and axial load of 8000 Kg showed the best behavior.

  9. The study of intergranular corrosion in aircraft aluminium alloys using X-ray tomography

    International Nuclear Information System (INIS)

    Research highlights: ? IGC is stochastic, where initiation is statistical and growth kinetics was somewhat predictable. ? Dissolved oxygen concentration was more important than the concentration of salt in the droplet. ? A limiting depth occurred for AA2024, whereas no limiting depth occurs for AA7050 after 168 h exposure. ? A limiting depth may be controlled by the transport of dissolved oxygen down the corrosion fissure. ? A limiting IGC depth is dependent on the overpotential of the SDZ (adjacent to the grain boundary). - Abstract: Atmospheric corrosion is one of the leading causes of structural damage to aircraft. Of particular importance is pitting and intergranular corrosion, which can develop into fatigue cracks, stress corrosion cracks, or exfoliation. Therefore it is of interest to the Australian Defence Force (ADF) to understand how corrosion ensues in susceptible aircraft aluminium alloys, such as AA2024-T351 and 7050-T7451. However, there are many difficulties in measuring the extent of intergranular corrosion, since it is predominantly hidden below the surface. Traditionally, cross-sectioning has been used to view and measure the depth of attack. In the present work, 2 mm diameter pin specimens were contaminated with a droplet of 3.5% NaCl and exposed to constant humidity that resulted in intergranular corrosion. X-ray computed tomography was then used to non-destructively assess the depth and volume of corrosion both as a function of time in 97both as a function of time in 97% relative humidity, and as a function of relative humidity after 168 h exposure. Both corrosion depth and volume increased with time, but there was evidence for a limiting depth in AA2024. Depth and volume also increased with relative humidity of the environment, for which the time-of-wetness and oxygen concentration of the droplets were considered the important factors in driving the corrosion process.

  10. Influence of Hot Deformation on Mechanical Properties and Microstructure of a Twin-Roll Cast Aluminium Alloy EN AW-6082

    Science.gov (United States)

    Grydin, O.; Stolbchenko, M.; Nürnberger, F.; Schaper, M.

    2014-03-01

    Thin strips of medium- and high-strength age-hardening aluminium alloys are widely used in the automotive industry. Reducing their production costs caused by high energy consumption is an actual challenge. The implementation of the twin-roll casting technology is promising. However, mechanical properties of directly cast high-alloyed thin aluminium strips are oftentimes inadequate to standard specifications. In this work, the influence of a hot deformation following a twin-roll cast strip process on the mechanical properties and microstructure is investigated. For this study strips of age-hardening aluminium alloy EN AW-6082—manufactured at a laboratory scaled twin-roll caster—were single-pass rolled at temperatures of 420 °C and true strains of up to 0.5. The mechanical properties of the as-cast and by different strains hot deformed material in the soft-annealed and age-hardened states were characterized by tensile tests. The results reveal that the twin-roll cast material features the necessary strength properties, though it does not meet the standard requirements for ductility. Furthermore, the required minimum strain during hot rolling that is necessary to ascertain the standard specifications has been determined. Based on micrographs, the uniformity of the mechanical properties and of the microstructure as a result of recrystallization due to hot metal forming and heat treatment were determined. A fine-grain microstructure and satisfactory material ductility after prior rolling with a true strain above 0.41 for the age-hardened state T6 and above 0.1 for the soft-annealed state O have been established.

  11. Accelerated growth of oxide film on aluminium alloys under steam: Part II: Effects of alloy chemistry and steam vapour pressure on corrosion and adhesion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Bordo, Kirill

    2015-01-01

    The steam treatment of aluminium alloys with varying vapour pressure of steamresulted in the growth of aluminium oxyhydroxide films of thickness range between 450 - 825nm. The surface composition, corrosion resistance, and adhesion of the produced films was characterised by XPS, potentiodynamic polarization, acetic acid salt spray, filiform corrosion test, and tape test. The oxide films formed by steam treatment showed good corrosion resistance in NaCl solution by significantly reducing anodic and cathodic activities. The pitting potential of the surface treated with steam was a function of the vapour pressure of the steam. The accelerated corrosion and adhesion tests on steam generated oxide films with commercial powder coating verified that the performance of the oxide coating is highly dependent on the vapour pressure of the steam.

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

    Science.gov (United States)

    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'écoulement plastique en fonction de la vitesse de déformation pour des valeurs comprises entre 10^{-3} s^{-1} et 10^6 s^{-1}.

  13. Fatigue crack growth resistance of gas tungsten arc, electron beam and friction stir welded joints of AA2219 aluminium alloy

    International Nuclear Information System (INIS)

    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 effect of three welding processes on fatigue crack growth behaviour is reported in this paper. 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 FSW joints are exhibiting superior fatigue crack growth resistance compared to EBW and GTAW joints. This was mainly due to the formation of very fine, dynamically recrystallised grains and uniform distribution of fine precipitates in the weld region.

  14. Measurement of the residual stress field in MIG-welded Al-2024 and Al-7150 aluminium alloy compact tension specimens

    International Nuclear Information System (INIS)

    Neutron diffraction has been used to measure the residual-stress field in MIG-welded Al-2024 and Al-7150 aluminium alloy compact-tension (CT) specimens. The measurements were made on the POLDI time-of-flight diffractometer, which uses a multiple frame overlap method. Strains in the three principal directions of each specimen were determined from the measured lattice plane spacing as a function of position through the weld relative to stress-free reference lattice plane spacings obtained from a comb-like reference sample. The resultant calculated residual stresses are compared to those existing in the original welded plate from which the specimens were machined

  15. Aluminium alloy containing iron and nickel. Influence of structure and composition on the corrosion behaviour in high temperature water

    International Nuclear Information System (INIS)

    The corrosion structures are determined on a series of aluminium (A9) base alloys which contain a total Fe + Ni not superior to 3%. The tests are carried out to 5,000 hours in 350 deg. C deionized water in autoclave. The principal results were as follows: - For iron and nickel contents superior to 0,5%, the first factor is the distribution structure of insoluble intermetallic compounds: the particles must be as fine and randomly dispersed as possible. - The corrosion products developed on the surface may be subdivided in three distinct layers which total thickness tends rapidly towards a limit and stabilises itself. (author)

  16. Effect of tool design on the microstructure and microhardness of friction stir processed 5005-H34 aluminium alloy

    Science.gov (United States)

    Mikhail, J.; Ibrahim, R.; Lathabai, S.

    2013-08-01

    The effect of tool design on microstructure and properties of friction stir processed study aluminium alloy AA 5005-H34 (Al-Mg) was investigated using three different FSP tools with different pin designs. The application of FSP resulted in fine, fully recrystallised microstructures and the processed zone was defect-free for some of the pin designs. Significant grain refinement from an initial pancake-like microstructure with a grain size of about 192 ?m in the base material to 10- 20 ?m in the processed regions was achieved.

  17. Evolution of Artificial Neural Network (ANN) model for predicting secondary dendrite arm spacing in aluminium alloy casting

    Scientific Electronic Library Online (English)

    D., Hanumantha Rao; G. R. N., Tagore; G., Ranga Janardhana.

    2010-09-01

    Full Text Available Extensive solidification simulations are conducted using finite difference method on an aluminium alloy casting. Orthogonal experimental array layout is considered for running experimental simulations. Microstructural parameter Secondary Dendrite Arm Spacing (SDAS) at three different locations was p [...] redicted as response variable, through solidification simulations by varying the process parameters. The input process variables are pouring temperature, insulation on riser and chill volume heat capacity. An Artificial Neural Network (ANN) model was developed to predict the response variable for varied input process variables. Through sensitivity analysis the influence of input process variables on output response was obtained. The results obtained from solidification simulations and ANN model are validated experimentally.

  18. Study of Residual Stress Tensors in High-Speed Milled Specimens of Aluminium Alloys Using a Method of Indent Pairs

    Directory of Open Access Journals (Sweden)

    Felipe Víctor Díaz

    2010-12-01

    Full Text Available From data obtained using a method of indent pairs it was possible to analyse different residual stress states generated in high-speed milled specimens of AA 6082-T6 and AA 7075-T6 aluminium alloys. The present method integrates a special device of indentation into a universal measuring machine, allowing the introduction of elongated indents to significantly reduce the absolute error of measurement. Diverse protocols for operations of high-speed face milling allow us to compare residual stress tensors inherent to climb and conventional cutting zones. Through an exhaustive analysis of the Mohr’s circles corresponding to those zones, a relationship was detected, which expresses the sensitivity of both alloys to develop surface residual stresses.

  19. INVESTIGATION OF EFFECT OF COOLING CONDITIONS ON HARDNESS OF THE AA 2024 AND AA 2014 WROUGHT ALUMINIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Hülya KAÇAR DURMU?

    2003-01-01

    Full Text Available Mechanical properties of some aluminum alloys can be changed with precipitation hardening. This intermetallic precipitates are incoherent with the main structure and increased mechanical properties. Cooling rates after solid solution process effects properties after precipitation. In applications, however this is not taken into consideration. In this study, AA 2014 and AA 2024 Aluminium Alloy specimens were hold for one hour at 495±3 0C and formed a solid solution. Specimens were quenched at this temperature with different cooling rtes . later artificial aging was applied at 150 0C and 180 0C. The hardness and microstructure variations of the specimens were investigated depending on the cooling rates and artificial aging temperatures.

  20. Behaviour of different bare and anodised aluminium alloys in the atmosphere

    OpenAIRE

    Bartolome?, Mª J.; Ri?o, J. F. Del; Escudero, E.; Feliu Jr, S.; Lo?pez, Vi?ctor; Otero, Eduardo; Gonza?lez Ferna?ndez, Jose? Antonio

    2008-01-01

    Exposure tests in natural atmospheres are an indispensable means for determining the behaviour and durability of metallic materials in the atmosphere. The corrosion behaviour of bare aluminium and anodised aluminium with three different coating thicknesses has been evaluated for two years' exposure in two natural atmospheres of very different corrosivities: one urban and the other marine. Several techniques have been used to evaluate changes in the specimens during exposure, but spec...

  1. Investigation of Some Schiff Bases as Corrosion Inhibitors for Aluminium Alloy in 0.5 M Hydrochloric Acid Solutions

    Science.gov (United States)

    Muniandy, M. T.; Rahim, A. Abdul; Osman, H.; Shah, A. Mohd; Yahya, S.; Raja, P. Bothi

    The inhibitory effect of some Schiff bases viz. N,N?-bis(2-hydroxybenzylidene)-1,3-diaminobenzene (SB1), N,N?-bis(4-bromobenzylidene)-1,3-diaminobenzene (SB2) and N,N?-bis(2-hydroxy-5-bromobenzylidene)-1,3-diaminobenzene (SB3) on the corrosion of aluminium alloy in 0.5 M HCl acid have been studied using weight loss measurements, potentiodynamic polarization and Scanning Electron Microscopy (SEM). The experimental results showed that these Schiff bases SB1, SB2 and SB3 efficiently inhibit the corrosion of aluminium alloy in 0.5 M HCl medium and found to follow almost similar corrosion inhibition pattern. The potentiodynamic polarization curves revealed that, all the studied Schiff bases are mixed type inhibitors with a predominantly cathodic action and their inhibition efficiencies increased with increasing inhibitor concentration. The adsorption of Schiff bases was found to follow Langmuir adsorption isotherm. SEM study revealed that these compounds protect the metal corrosion by adsorption on its surface to form a protective layer. The inhibition performance depends strongly on the type of functional groups substituted on the benzene ring.

  2. Effect of Ni Content on the Hardness, Corrosion Rate and Heat Stability of Cladding Structure Material With an Aluminium Base Alloy

    International Nuclear Information System (INIS)

    The development of cladding structure material with an aluminium base alloy was performed by variation of Ni content in the alloy. Various of Ni content in alloy will generates material properties changes in mechanical, physical and thermal. The investigation and development of cladding structure material was studied in order to get materials which have good mechanical properties and corrosion resistance. The examination of the hardness of AlFeNi structure materials was observed using Vickers method. The microstructure observation was performed by optical metallography. The corrosion rate measurement was done by the potentiostat. The thermal analysis was done based on specific heat pattern. The hardness examination results of AlFeNi alloy with 1%, 2%, 3%, 4% wt Ni contents were respectively about 50 HV, 53 HV, 58 HV and 64 HV. The hardness of AlFeNi alloy showed improvement with increasing Ni content in the alloy. Result of optical metallographic observation showed microstructure of AlFeNi alloy change along with the increasing of Ni content in the alloy. Microstructure of the AlFeNi alloy with 1%, 2%, 3% and 4% wt Ni contents showed that grain structure was dendritic formed inclined smaller. The corrosion rate observation result of the AlFeNi alloy with 2%, 3% and 4% wt Ni contents were about 0.064 mpy, 0.16 mpy, 0.39 mpy and 0.96 mpy. The corrosion rate of AlFeNi alloy showed tend to increase with increasing of Ni content in the alloy. The specific heat analysis res the alloy. The specific heat analysis result of the aluminium and aluminium alloy at the variation temperature up to 400oC showed tendency of specific heat pattern changes were relatively the same. Thermal properties of AlFeNi alloy was relatively stable and its pattern relatively the same with the aluminium. The AlFeNi alloy without any thermal properties changes although at the higher temperature up to 240oC. (author)

  3. Determination of the alloyed amount of cerium and microdistribution of cerium in steel, cast iron and aluminium by radioassay and autoradiography

    International Nuclear Information System (INIS)

    An experimental method for the determination of the amount of rare earth alloyed in steel, cast iron, aluminium and its alloy and a coating-autoradiography technique have been developed. Microautoradiographs show that the cerium is distributed in the grains, but cerium mainly segregates along the grain boundaries and dendrite boundaries of aluminium, Al-Mg alloys and heat-resisting Fe-Cr-Al alloys. Cerium contained in the pearlite is more than that in the ferrite of 16Mn and 25MnTiB steels. There is little cerium in the ferrite and pearlite which surround the spheroidal graphite, while in the pearlite and ledeburite which are located far from the spheroidal graphite there is much cerium. Cerium is distributed uniformly in flake graphite, while it is distributed in various ways in spheroidal graphite. (orig.)

  4. Effect of Coupon Orientation on Corrosion Behaviour of Aluminium Alloy Coupons in the Spent Fuel Storage Section of the IEA-R1 Research Reactor

    International Nuclear Information System (INIS)

    Surveillance programmes to monitor the corrosion of aluminium clad spent research reactor fuels have used test racks containing horizontal metallic coupons. Spent MTR-type fuel elements are usually stored vertically, with their fuel plates, also vertical. Hence, the influence of coupon orientation on the corrosion behaviour of aluminium alloy coupons exposed to the spent fuel storage section of the IEA-R1 research reactor in Sao Paulo, Brazil, has been studied. Circular coupons of aluminium alloys AA 1050 and AA 6061, oriented both vertically and horizontally, were exposed to the storage section water for a year. Individual and coupled coupons were exposed to simulate general, crevice and galvanic corrosion. The storage section water parameters were periodically measured. Pitting was the main form of corrosion and coupon orientation had a marked effect on the extent of pitting. Vertically oriented coupons pitted less than horizontally oriented coupons. (author)

  5. Investigation of the effects of Magnesium Content and Cooling Rate on the Mechanical Properties of Aluminium-Magnesium Alloys Refined with Titanium-Boride Master Alloy

    Directory of Open Access Journals (Sweden)

    Fatai Olufemi ARAMIDE

    2012-11-01

    Full Text Available Investigations into the effects of magnesium content and cooling rates on the mechanical properties of aluminium-magnesium alloys refined with titanium-boride master alloy was conducted. Experimental samples were produced from melt with Mg content ranging from 0% to 8%, poured and cooled in air, water and oil. Standard sample dimensions were produced for tensile and hardness tests. It was observed that both the Mg content and the cooling rate affect the mechanical properties; elongation (ductility reduced with increased Mg content while the hardness of the samples increased with the Mg content. It was concluded that the sample poured and cooled in water possessed the optimum mechanical properties (combination of ductility and hardness within the range of composition of maximum ultimate tensile strength (UTS.

  6. Intermetallic phase particles in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys

    Directory of Open Access Journals (Sweden)

    G. Mrówka-Nowotnik

    2009-08-01

    Full Text Available Purpose: In the technical Al alloys even small quantity of impurities - Fe and Mn - causes the formation of new phase components. Intermetallic particles form either on solidification or whilst the alloy is at a relatively high temperature in the solid state, e.g. during homogenization, solution treatment or recrystallization. The exact composition of the alloy and casting condition will directly influence the selection and volume fraction of intermetallic phases. The main objective of this study was to analyze the morphology and composition of complex microstructure of intermetallic phases in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy (LM, scanning (SEM electron microscopy in combination with X-ray analysis (EDS using polished sample, and X-ray diffraction (XRD to identify intermetallics in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys.Findings: The results show that the microstructure of cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys in T6 condition consisted a wide range of intermetallic phases. By using various instruments (LM, SEM, XRD and techniques (imagine, EDS following intermetallic phases were identified: ?-Al5FeSi, ?-Al15(FeMn3Si - in AlSi5Cu1Mg alloy and Al7Cu4Ni, Al12Cu23Ni, Al2CuMg, AlCuFeNi - in AlCu4Ni2Mg2 alloy.Research limitations/implications: In order to complete and confirm obtained results it is recommended to perform further analysis of the investigated aluminium alloys. Therefore it is planned to include in a next studies, microstructure analysis of the alloys by using transmission electron microscopy technique (TEM.Practical implications: Since the morphology, crystallography and chemical composition affect the intermetallic properties, what involves changes of alloy properties, from a practical point of view it is important to understand their formation conditions in order to control final constituents of the alloy microstructure.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phases occurring in the cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys. This study has showed that the chemical phenol extraction method for the cast aluminium alloy is applicable.

  7. Structure and corrosion resistance of aluminium AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys

    Directory of Open Access Journals (Sweden)

    J. Szewczenko

    2010-07-01

    Full Text Available Purpose: The aim of the work was the evaluation of corrosion resistance and structure of aluminium AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys.Design/methodology/approach: The corrosion resistance tests of investigated alloys were carried out by means of potentiodynamic method registering anodic polarization curves in 3.5% NaCl solution at room temperature. Registering anodic polarization curves was conducted at the potential rate equal to 1mV/s. As the reference electrode was used saturated calomel electrode (SCE and the auxiliary electrode was platinum electrode. Mechanical properties were evaluated on the basis of Vickers hardness test. The test was realized with the use of Hauser hardness tester. The observations of the surface morphology after corrosive tests were carried out using Digital Scanning Electron Microscope DSM 940 OPTON.Findings: The investigations of corrosion resistance of examined aluminium alloys shows that the highest corrosion resistance in 3.5% NaCl solution was observed for AlZn5Mg1 aluminium alloy.Practical implications: The obtained results can be used for searching the appropriate way of improving the corrosion resistance of analysed alloys because better corrosion resistance, lightweight of aluminium and its alloys makes them as most attractive for the steel replacement in shipbuilding.Originality/value: The corrosion behaviour in chloride solution of AlMg2.5; AlMg5Mn and AlZn5Mg1 alloys was investigated.

  8. High-temperature brazing of graphite using aluminium as brazing alloy

    International Nuclear Information System (INIS)

    The possibility of enhancing the strength of brazed joints, as well as the effect of the parameters of resistance heating of graphite VPP with PA-4 aluminium on the structure, composition and strength of the joint have been studied. It has been established that brazing of graphite materials, using an aluminium solder will produce a heat-resistant joint of a graphitic composition if the brazing temperature exceeds 2200 deg C. Thermocycling in the course of brazing results in a substantial (1.5-fold) increase in the strength of brazed joints

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

    Science.gov (United States)

    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.

  10. Overload effects on a ferritic-baintic steel and a cast aluminium alloy: two very different behaviours

    Energy Technology Data Exchange (ETDEWEB)

    Saintier, N. [Arts et Metiers Paris Tech, I2M, UMR CNRS, Universite Bordeaux 1, Talene Cedex (France); El Dsoki, C.; Kaufmann, H.; Sonsino, C.M. [Fraunhofer-Institute for Structural Durability and System Reliability LBF, Darmstadt (Germany); Dumas, C. [RENAULT, Technocentre, Guyancourt Cedex (France); Voellmecke, F.J. [BORBET GmbH, Hallenberg-Hesborn (Germany); Palin-Luc, T.; Bidonard, H.

    2011-10-15

    Load controlled fatigue tests were performed up to 10{sup 7} cycles on flat notched specimens (K{sub t} = 2.5) under constant amplitude and variable amplitude loadings with and without periodical overloads. Two materials are studied: a ferritic-bainitic steel (HE400M steel) and a cast aluminium alloy (AlSi7Mg0.3). These materials have a very different cyclic behaviour: the steel exhibits cyclic strain softening whereas the Al alloy shows cyclic strain hardening. The fatigue tests show that, for the steel, periodical overload applications reduce significantly the fatigue life for fully reversed load ratio (R{sub {sigma}} = -1), while they have no influence under pulsating loading (R{sub {sigma}} = 0). For the Al alloy overloads have an effect (fatigue life decreasing) only for variable amplitude loadings. The detrimental effect of overloads on the steel is due to ratcheting at the notch root which evolution is overload's dependent. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. EVALUATION & COMPARISION OF MECHANICAL PROPERTIES OF ALUMINIUM ALLOY 5052 REINFORCED WITH SILICONCARBIDE, GRAPHITE AND FLY ASH HYBRID METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    ANKUSH SACHDEVA

    2013-10-01

    Full Text Available The engineering fraternity has always been looking forward to develop an outstanding and wonder-materials which would fit the ever-changing demands of the world. In order to fullfill the demands various newdiscoveries have been made by scientists, engineers and resrearchers. In todays competitive world many, materials have been tried for various unexplored conditions , but the never ending demand of the world encourages the researchers to develop the new material. Now the researchers are preparing the material by the combination of different materials called hybrid composite material.. Metal Matrix Composites (MMCs have emerged as a class of materials suitable for structural, aerospace, automotive, electronic, thermal and wearapplications owing to their advantages over the conventional materials. The present study was taken up to explore the possibility of using different reinforcements (silicon carbide, fly ash and graphite to enhance the properties of aluminium alloy (Al5052 composites. Different samples were prepared from the aluminium withvarying reinforcement composition. The mechanical properties studied after the experiment were strength, hardness and elongation.Further, these composites were characterized with the help of, mechanical testing and scanning electron microscopy.

  12. Identification of phase composition of AlSi5Cu2Mg aluminium alloy in T6 condition

    Directory of Open Access Journals (Sweden)

    M. Wierzbi?ska

    2008-04-01

    Full Text Available Purpose: The purpose of this paper is to present the results of studies of AlSi5Cu2Mg cast alloy in T6 condition at an angle of intermetallic phases composition. It was found that the investigated alloy microstructure consists of three different, as regards shape intermatallic phases.Design/methodology/approach: In this study, several methods were used, such as: optical light microscopy (LM scanning electron microscopy (SEM in combination with X-ray analysis (EDS using polished samples, and calorimetric analysis (DSC, to identify of phase composition in AlSi5Cu2Mg alloy.Findings: The results show that three intermetallic phases in AlSi5Cu2Mg alloy microstructure presented only one type of the phase, the ?–AlFeMnSi phase. The chemical composition, morphology, shape (needle or “Chinese script” and distribution of ? – AlFeMnSi phase depend on the parameters of the crystallization process. Netherless, it is possible to change this parameters during heat treatment process.Research limitations/implications: Although the morphology and ? – AlFeMnSi phase particles distribution have a significant impact on the mechanical properties (especially on the crack resistance of the AlSi5Cu2Mg alloy, the main strengthening factor is the existence of the dispersion phase which was not subjected to examination in the research presented in this paper. Therefore, in order to complete and confirm obtained results it is recommended to perform further analysis of the alloy by using transmission electron microscopy technique (TEM.Practical implications: From a practical point of view it is important, that there is a possibility to influence morphology, shape and distribution of intermetallic ? – AlFeMnSi phase by heat treatment parameters, to obtain optimal mechanical properties of AlSi5Cu1Mg alloy according to application.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phases occurrnig in the 4xxx series aluminium alloys, provide wide data about their chemical composition, morphology, shape and distribution.

  13. Microstructure, local and global mechanical properties of friction stir welds in aluminium alloy 6005A-T6

    International Nuclear Information System (INIS)

    The effect of the welding speed on the microstructure, local and overall mechanical properties of friction stir welded joints has been investigated in the aluminium alloy 6005A-T6. The fine hardening precipitation within the heat-affected zone has been characterized by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Post-welding heat treatments have been applied to obtain indications on the level of solid solution supersaturation in the as welded state. The local mechanical behaviour was determined using thin specimens extracted from various regions of the weld. The overall properties were measured on samples cut perpendicular to the weld. Specific attention was devoted to the relationship between the local microstructure and local hardening properties in the weakest region, which govern the overall strength and ductility of the welds

  14. Electrochemical corrosion characteristics of aluminium alloy 6061 T6 in demineralized water containing 0.1 % chloride ion

    International Nuclear Information System (INIS)

    Direct current electrochemical method is one of the techniques has been used to study the corrosion behaviour of metal/ alloy in its environment. This paper attempts to investigate the corrosion behaviour of Al 6061 T6 immersed in Reactor TRIGA Mark II pool water containing about 0.1 % NaCl content. The result shown that the corrosion rate value of the aluminium 6061 T6 increased with the presence of 0.1 % Ion Chloride content in the demineralized water reactor pool as compared to normal demineralized water. This is due to aggressiveness of chloride ion attack to metal surface. Beside corrosion rate analysis, the further tests such as corrosion behaviour diagram, cyclic polarization have been carried and the results have been reported. (Author)

  15. Electrochemical corrosion characteristics of aluminium alloy 6061 T6 in demineralized water containing 0.1 % chloride ion

    International Nuclear Information System (INIS)

    Direct current electrochemical method is one of the techniques has been used to study the corrosion behaviour of metal/alloy in its environment. This paper attempts to investigate the corrosion behaviour of Al 6061 T6 immersed in Reactor TRIGA Mark II pool water containing about 0.1% NaCl content. The result shown that the corrosion rate value of the aluminium 6061 T6 increased with the presence of 0.1 % Ion Chloride content in the demineralized water reactor pool as compared to normal demineralized water. This is due to aggressiveness of chloride ion attack to metal surface. Beside corrosion rate analysis, the further tests such as corrosion behaviour diagram, cyclic polarization have been carried and the results have been reported. (author)

  16. Characterization of AA7050 aluminium alloy processed by ECAP; Caracterizacao da liga de aluminio AA7050 processada por ECAP

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, K.R.; Guido, V. [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil). Inst. de Pesquisa e Desenvolvimento; Travessa, D.N. [Empresa Brasileira de Aeronautica (EMBRAER), Sao Jose dos Campos, SP (Brazil); Jorge Junior, A.M. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    The commercial AA7050 aluminium alloy in the solution heat treated condition (W) was processed by ECAP through route A. Two pressing temperatures (room and 150 deg C and velocities (5 and 30mm/min) were used, as well as different number of passes. The effect of such variables on the microstructure evolution was evaluated using optical and transmission electron microscopy with EDX microanalysis, and xray diffraction. It was found that the microstructure has been refined by ECAP, as a result of subgrains formed within deformation bands. ECAP at 150 deg C resulted in intense precipitation of plate like {eta} phase, which evolves to equiaxial morphology as the number of passes increases. (author)

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

    International Nuclear Information System (INIS)

    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 = ? min/? max = 0.1. The microstructure resulting from the FSW process was studied by employing optical and scanning electron microscopy

  18. Experimental and numerical analysis of in- and out- of plane constraint effects on fracture parameters: Aluminium alloy 2024

    Directory of Open Access Journals (Sweden)

    Huta? P.

    2013-06-01

    Full Text Available The influence of in- and out- of plane constraints on the behaviour of a crack under mode I loading conditions is studied. The independence of the stress intensity tensor, with respect to the specimen thickness B shows that under loss of constraint conditions higher order members of the Williams’ tensor expansion must be considered if the experimental results for increasing apparent fracture toughness resulting from decreasing specimen thickness are to be explained. This is achieved using the constraint curves that define the intensity field tensor along the crack propagation direction and can be alternative to the T-stress approach. This approach is then applied to crack instability assessment for program compact tension (CT — positive values of T-stress and three point bending (3PB— from negative to positive values of T-stress specimens with different thicknesses. The theoretical results are compared with experimental ones obtained from the research program on aluminium alloy 2024.

  19. Quantitative TEM study of the precipitation microstructure in aluminium alloy Al(MgSiCu) 6056 T6

    International Nuclear Information System (INIS)

    The precipitate microstructure in the last-generation aluminium alloy 6056 T6 [AlMgSiCu] is investigated using three complementary techniques of transmission electron microscopy (TEM) with a special focus on the density and volume fraction of strengthening particles. High-resolution TEM allows the identification of the precipitates and the measurement of the precipitate sizes to be performed. Conventional TEM is used to evaluate the number of precipitates in the investigated area as well as their distribution in the matrix. In situ TEM straining, via the analysis of the dislocation slip traces, permits to determine precisely the thickness and the volume of the foil in the region where the precipitates are analysed. Taking into account the shape and the dimensions of precipitates with respect to the foil thickness, a novel methodology for measuring the volume density and the volume fraction of precipitates is proposed

  20. Determination of vanadium (3) and vanadium (4) in the presence of each other in quartz glasses alloyed with aluminium

    International Nuclear Information System (INIS)

    A method is developed of vanadium (3) and vanadium (4) determination in the presence of each other in quartz glasses alloyed with aluminium. Analytical characteristics of vanadium (3) reaction with tiron are studied. Maximum hight absorption of a dyed vanadium (3) complex is observed at lambda=570 nm and pH=8-9. To eliminate the effect of Al, sodium fluoroborate is used as a masking agent. The vanadium (3) threshold determination equals 0.01 ?g/ml. The reaction with acid chrome blue is used for vanadium (4). The vanadium (4) threshold determination is 3.2x10-3 ?g. The total content of vanadium in glasses has been . established from the above reaction, the content of vanadium (3) has been determined from the reaction with tiron, and the number of vanadium (4)-according to the difference

  1. Activation analysis of high-purity metals. Electrical properties of dilute aluminium alloys with rare earth elements

    International Nuclear Information System (INIS)

    Residual electrical resistivity, the Hall coefficient and the transverse magnetoresistance coefficient have been measured at 4.2 K on dilute aluminium alloys with rare earth elements of about 10 at.ppm. The concentration of these elements, which is indispensable for the analysis of the data, has been determined by neutron activation analysis using the graphite irradiation facility. The resistivity contribution of rare earth element per at.ppm ranges between 0.1-0.2 p?m for lighter elements that Eu. On the other hand, this value for heavier elements than Dy rapidly increases and reaches 2.4 p?m. The anisotropy of the mean free path of conduction electrons is estimated from the Hall coefficient and the magnetoresistance coefficient according to the three-group model. The scattering features inherent in the rare earth elements are discussed. (author)

  2. Effect of weld morphology on mechanical response and failure of friction stir welds in a naturally aged aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: ? Friction stir welds of AA 6063-T4 are obtained using three tool pin profiles. ? Signature of weld defects in mechanical response of welds is investigated. ? Correlation between peak temperatures in HAZs and their hardness is studied. ? Reasons for strengthening of WNZ and softening of HAZs are found using TEM and XRD. ? A FEM model for the weld zone is developed and validated. -- Abstract: Friction stir butt welds in 6063-T4 aluminium alloy were obtained using square and two tapered tool pin profiles. Tensile tests at 0°, 45°, and 90° to the weld line, hardness contours in the weld cross-section, temperatures in the heat affected zones, cross-sectional macrographs, transmission electron micrographs, and X-ray diffraction studies were used to characterize the welds. In transverse weld specimen, tunnel defects appearing at higher weld speeds for tapered pin profiles, were found to result in mechanical instabilities, i.e. sharp drops in load–displacement curves, much before macroscopic necking occured. Further, in comparison to the base metal, a marked reduction in ductility was observed even in transverse specimen with defect free welds. Hardness contours in the weld cross-section suggest that loss in ductility is due to significant softening in heat affected zone on the retreating side. Transmission electron microscopy images demonstrate that while recovery and overaging are responsible for softening in the heat affected zone, grain size refinement from dynamic recrystallization is responsible for strengthening of the weld nugget zone. X-ray diffraction studies in the three weld zones: weld nugget zone, heat affected zone, and the base metal corroborate these findings. A weld zone model, for use in forming simulations on friction stir welded plates of naturally aged aluminium alloys, was proposed based on mechanical characterization tests. The model was validated using finite element analysis.

  3. Modification of the EN AC-42000 aluminium alloy with use of multicomponent electrolysis of sodium salt

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2014-01-01

    Full Text Available The present paper discusses results of research concerning the process of continuous modification of the EN AC-42000 (AlSi7Mg alloy with sodium, based on electrolysis of sodium salts, occurring directly in a melting pot with the liquid alloy. Sodium ions formed as a result of dissociation of the sodium salt and the electrolysis are “transferred” through walls of the retort made from solid electrolyte. Upon contact with the liquid alloy, as a cathode, sodium ions are transformed into atomic state, modifying the alloy. As a measure of the extent of the alloy modification impact strength, elongation A5 and analysis of the microstructure have been obtained, which confirmed the achievement of modification of the alloy under analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Strain hardening of aluminium alloy 3004 in the deep drawing and ironing processes

    OpenAIRE

    Courbon, J.; Duval, J.

    1993-01-01

    The evolution of material hardening resulting from the canmaking operations on aluminium beverage cans has been investigated. Tensile tests in cup walls revealed that deep drawing induced softening in the hoop direction and hardening in the meridian direction. This anisotropy is retained in the ironing operation. Changes in strain path on a heavily cold-rolled material probably cause such a complex behaviour. To determine hardening laws for deep drawing, simple shear tests were thus performed...

  6. Protecting Melted Zinc-Aluminium based Foundry Alloys Against Hydrogen Pick-Up

    Directory of Open Access Journals (Sweden)

    Krajewski W.K.

    2014-06-01

    Full Text Available Praca po?wi?cona jest badaniom rafinacyjnej skuteczno?ci ?u?li ochronnych i rafinatorów stosowanych w technologii przetapiania cynku oraz stopów cynk-aluminium. Wykonane badania wykaza?y, i? Zn i stopy podwójne Zn-Al przetapiane pod ?u?lami ochronnymi oraz przerafinowane przed odlaniem do formy wykazuj? zwi?kszon? plastyczno?? i zwi?kszon? czysto??, potwierdzon? podwy?szon? g?sto?ci? masy. Dodatkowo, wzrastaj? uzyski metalurgiczne.

  7. Thermoelectric power study of non-isothermal precipitation in commercial (8011) aluminium-iron-silicon alloys

    International Nuclear Information System (INIS)

    Precipitation processes in as-cast, homogenized and deformed samples of an 8011 commercial alloy have been studied by thermoelectric power under non-isothermal conditions, verifying the sensitivity of the thermoelectric power to the kinetics of the iron atoms in solid solution. The thermoelectric power versus temperature diagrams show that rolling favors the phase precipitation and that the kinetic behavior of the dominant alloying additions in the 8011 alloy is similar to the ones observed in other Al-Fe-Si alloys. The characteristic temperatures for each studied microstructural condition are reported. (orig.)

  8. Plastic Deformation at Moderate Temperatures of 6XXX-series Aluminium Alloys

    OpenAIRE

    Aastorp, Knut Iver

    2002-01-01

    The present work has been carried out in order to investigate Al-Mg-Si alloys that are deformed at moderate temperatures. These temperatures are in the range between 200 C and 300 C. Also some experiments are performed at room temperatures. Two deformation models have been applied in the experiments: material deformation by compression testing and by forward extrusion.

    The investigated alloys are AA6063, AA6082 and an alloy that is named “Alloy R” in this work. ...

  9. Influences of tool pin profile and tool shoulder diameter on the formation of friction stir processing zone in AA6061 aluminium alloy

    International Nuclear Information System (INIS)

    AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, 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 tool pin profile play a major role in deciding the weld quality. In this investigation an attempt has been made to understand the effect of tool pin profile and tool shoulder diameter on FSP zone formation in AA6061 aluminium alloy. Five different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular and square) with three different shoulder diameters have been used to fabricate the joints. The formation of FSP zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the FSP zone formation. From this investigation it is found that the square pin profiled tool with 18 mm shoulder diameter produced mechanically sound and metallurgically defect free welds compared to other tool pin profiles

  10. Optacial Appearance of Aluminium

    OpenAIRE

    Aggerbeck, Martin

    2010-01-01

    Three commercial aluminium alloys (1050, 5754 and 6082), with different surface treatments (combinations of etching and polishing) has been investigated by LOM, GDOES and photospectrometry, to study how and why alloy composition and surface treatment affects the optical appearance of an Al specimen. It is found that reflection colour is alloy dependent and reflection intensity depends on both surface treatment and alloy purity. Studies have shown that a specimen with high surfa...

  11. Design, Analysis and Optimization of Three Aluminium Piston Alloys Using FEA

    Directory of Open Access Journals (Sweden)

    Ajay Raj Singh

    2014-01-01

    Full Text Available This paper describes the stress distribution and thermal stresses of three different aluminum alloys piston by using finite element method (FEM. The parameters used for the simulation are operating gas pressure, temperature and material properties of piston. The specifications used for the study of these pistons belong to four stroke single cylinder engine of Bajaj Kawasaki motorcycle. This paper illustrates the procedure for analytical design of three aluminum alloy pistons using specifications of four stroke single cylinder engine of Bajaj Kawasaki motorcycle. The results predict the maximum stress and critical region on the different aluminum alloy pistons using FEA. It is important to locate the critical area of concentrated stress for appropriate modifications. Static and thermal stress analysis is performed by using ANSYS 12.1. The best aluminum alloy material is selected based on stress analysis results. The analysis results are used to optimize piston geometry of best aluminum alloy.

  12. Interfacial microstructure and mechanical property of resistance spot welded joint of high strength steel and aluminium alloy with 4047 AlSi12 interlayer

    International Nuclear Information System (INIS)

    Highlights: • Steel and aluminium alloy were resistance spot welded with interlayer successfully. • Welded joint of steel and aluminium alloy with 4047 interlayer was a brazed joint. • Fe2(Al,Si)5 and Fe4(Al,Si)13 were formed at the steel/aluminium interface. • Reaction diffusion at the interface was inhibited by introduction of silicon atoms. • Welded joint property was improved greatly with the interlayer thickness of 300 ?m. - Abstract: Dissimilar materials of H220YD galvanised high strength steel and 6008-T66 aluminium alloy were welded by means of median frequency direct current resistance spot welding with employment of 4047 AlSi12 interlayer. Effects of interlayer thickness on microstructure and mechanical property of the welded joints were studied. The welded joint with interlayer employed could be recognised as a brazed joint. The nugget diameter had a decreased tendency with increasing thickness of interlayer under optimised welding parameters. An intermetallic compound layer composed of Fe2(Al,Si)5 and Fe4(Al,Si)13 was formed at the interfacial zone in the welded joint, the thickness and morphology of which varying with the increase of interlayer thickness. Reaction diffusion at the steel/aluminium interface was inhibited by introduction of silicon atoms, which restricted growth of Fe2(Al,Si)5. Tensile shear load of welded joints experienced an increased tendency with increasing interlayer thickness from 100 to 300 ?m, and the maximum tensile shear load of 6.2 kN was obtained with interlayer thickness of 300 ?m, the fractured welded joint of which exhibiting a nugget pullout failure mode

  13. Crystalline textures in aluminium-uranium alloys determined by neutron diffraction

    International Nuclear Information System (INIS)

    Textures of hot-rolled aluminum-uranium alloys and aluminum were determined by neutron diffraction. Sheets of alloys containing 8.0, 21.5 and 23.7 wt pct U, as well as pure aluminum, were obtained in a stepped rolling process, 15% reduction each step, 75% total reduction. During the rolling the temperature was 600 deg C. Alloys with low uranium contents are two phase systems in which an intermetallic compound UAl4, orthorhombic, is dispersed in a pure aluminum matrix. The addition of a few percent of Si in such alloys leads to the formation of UAl3, simple cubic, instead of UAl4. The Al - 23.7 wt pct U alloy was prepared with 2,2 wt pct of Si. The (200), (040) and (121) pole figures of the phase UAl4 of the Al-21.5 wt pct U alloy show a high degree of orientation defined as (010) |100|. The (111) reflection of the phase UAl3 of the Al-23.7 wt pct U alloy showed no preferred orientations. The (111) pole figures of the matrix of the alloys 21.5 and 23.7 wt pct U can be described satisfactorily by the same weakly developed texture, namely {113} . The (111) pole figure for the matrix of the Al-8.0 wt pct U alloy has the texture {113} , which is an intermediate case between the {110} texture of aluminum and the texture of the higher uranium-bearing alloys. For pure aluminum and the 8.0pct alloy the degree of the textures is still weak however higher than in the preceding cases. The (200) and (121) pole figures for the UAl4 of the 8.0 pct alloy show the same texture as the 21,5 pct alloy though with considerable more spread. The results indicate that the texture of the matrix is more dependent on the uranium concentration than on the texture of the intermetallic phases. This work also presents an improvement in the technique applied to texture measurements by using a sample fully bathed in the neutron beam. The method takes advantage of the low neutron absorption of the studied materials as well as of the negligible variation in the multiple scattering which occurs in a conveniently shaped sample having a weakly developed texture. (author)

  14. Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes

    International Nuclear Information System (INIS)

    Research highlights: ? Effect of alloying on the corrosion activity of sacrificial Al anodes. ? Sn in solid solution form is a key alloying element for activation of Al anodes. ? Ternary additions that increase Sn solubility decrease the potential of Al alloys. ? Elements bigger than Al expand the Al lattice and allow more Sn to dissolve in Al. ? Large ternary dopants can reduce Sn's solubility in Al if they form compounds with Sn. - Abstract: This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.

  15. Stress corrosion cracking of B13, a new high strength aluminium lithium alloy

    International Nuclear Information System (INIS)

    The present paper focuses on the study of SCC behaviour of a new Al-Cu-Li alloy. For this purpose, two conventional media - NaCl and NaCl + H2O2 - were used for comparison with commercial alloys 7075 and 8090. This new alloy shows lower susceptibility to SCC than conventional alloys as it does not undergo environmentally-induced embrittlement in NaCl solutions and in 1 M NaCl + 0.3% H2O2 in which the 7075 and 8090 alloys, respectively, undergo environmentally-induced fracture. Solution composition was modified in order to determine the environmental conditions and strain rates under which this new alloy will crack due to a stress corrosion cracking phenomenon. The addition of 0.6 M sulphates to 1 M NaCl + 0.3% H2O2 solution allows the definition of a range of strain rate (between 10-7 and 10-6 s-1) in which this new alloy undergoes stress corrosion cracking

  16. Impact of M2-Hss Tool Pin Profile in Fsw Welded Joints On Mechanical Properties Of Aa7075-T6 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    Venugopal S

    2014-05-01

    Full Text Available Friction stir, “welding is a solid state joining process and is widely being considered for aluminium alloys. The main advantage of FSW is the material that is being welded undergoes only localized changes. The welding parameter and tool pin profile play a major role in deciding the weld quality. In this work an effort has been made to analyze microstructure of aluminium AA 7075-T6 alloy. Three different tool profiles (Taper Threaded, cylindrical and square have been used to construct the joints in particular rotational speed. Tensile, Impact, micro hardness of mechanical properties of the joints have been evaluated and the formation of FSP zone has been analyzed microscopically. From the investigation it is found that the threaded cylindrical profile produces highly (defined Strength in welds.

  17. Strain hardening of aluminium alloy 3004 in the deep drawing and ironing processes

    International Nuclear Information System (INIS)

    The evolution of material hardening resulting from the canmaking operations on aluminium beverage cans has been investigated. Tensile tests in cup walls revealed that deep drawing induced softening in the hoop direction and hardening in the meridian direction. This anisotropy is retained in the ironing operation. Changes in strain path on a heavily cold-rolled material probably cause such a complex behaviour. To determine hardening laws for deep drawing, simple shear tests were thus performed because of the strain path similarity. They allowed to determine hardening laws over larger strains than tension could reach and revealed a saturation of stress. Altogether they proved adapted to the understanding of deep drawing. (orig.)

  18. Mechanical Behaviour of Friction Stir Welding Joints of Aluminium alloy of AA6351 with AA6351 and AA6351 with AA5083

    OpenAIRE

    Gopala Krishna, G.; Ram Reddy, P.; Manzoor Hussain, M.

    2014-01-01

    Modern structural application demands reduction in both the weight and as well as cost of the fabrication and production of materials. Aluminium alloys are the best choice for the reduction of weight, cost and replacing steels in many applications and Friction Stir Welding (FSW) process efficient and cost effective process. FSW is solid state welding process in which material is not melted during welding process so it overcomes many welding defects compared to conventional fusion welding proc...

  19. In-situ Observation and Mathematical Modelling of the Nucleation and Growth of Intermetallics and Micropores During the Solidification of Aluminium Alloys

    OpenAIRE

    Wang, Junsheng

    2009-01-01

    The performance of aluminium alloy castings is limited by the level of two major defects: porosity and iron intermetallics, because both phases can lead to the initiation and propagation of cracks of casting components at high cyclic regime. To improve the fatigue life and thus increase usage of these energy-saving light metals, the mechanisms by which such microstructure features form and possible approaches to control them were investigated via a mathematical model which was ...

  20. Selective laser melting of aluminium die-cast alloy: Paper presented at Fraunhofer Direct Digital Manufacturing Conference 2014, March 12-14, 2014, Berlin, Germany

    OpenAIRE

    Buchbinder, D.; Meiners, W.; Wissenbach, K.; Poprawe, R.

    2014-01-01

    The additive manufacturing technology Selective Laser Melting (SLM) is used for direct fabrication of metal-based functional components. SLM is well established in serial production for dental restoration as well as for tooling. Main concern for industrial application remains the scope of processible materials and resulting mechanical properties. Towards processing of aluminium alloys commercially available systems exist with comparability in terms of applied process parameters and resulting ...

  1. Fatigue behavior of GMAW welded Aluminium alloy AA7020; Comportamiento a fatiga de uniones soldadas GMAW de la aleacion de aluminio AA 7020

    Energy Technology Data Exchange (ETDEWEB)

    Bloem, C. A.; Salvador, M. D.; Amigo, V.; Vicente, A.

    2007-07-01

    The aim of this investigation is to evaluate the influence on the fatigue behavior by the finishing of the bulge in a welded aluminium-zinc-magnesium alloy AA7020. It was determined that total or partial elimination of the bulge has very little influence on its behavior, giving a very similar result on both cases, where one is better than the other by only 3%. (Author) 20 refs.

  2. Composite materials based on AlMg1SiCu aluminium alloy reinforced with halloysite particles

    Directory of Open Access Journals (Sweden)

    B. Tomiczek

    2013-11-01

    Full Text Available Purpose: The present work describes microstructure and technological, as well as mechanical properties of AlMg1SiCu matrix composite materials reinforced with halloysite particles by powder metallurgy techniques and hot extrusion. Design/methodology/approach: Mechanical milling, compacting and hot extrusion successively are considering as a method for manufacturing metal composite powders with a controlled fine microstructure and enhanced mechanical properties. Findings: A structure of newly developed composite materials reinforced with halloysite nanotubes prove that a mechanical milling process allow to improve the arrangement of reinforcing particles in the matrix material. A homogenous structure with uniformly arranged reinforcing particles can be achieved by employing reinforcement with halloysite nanotubes if short time of milling is maintained thus eliminating an issue of their agglomeration. Strong plastic deformations and fine grain size and the dispersion of halloysite reinforcing particles caused by mechanical milling is substantially reinforcing the composite materials reinforced with halloysite nanotubes as expressed with nearly a threefold increase in the hardness of composite powders as compared to the value of this quantity before milling. Research limitations/implications: Contributes to knowledge about technology, structure and properties of aluminium alloy matrix composite material reinforced with mineral nanoparticles. Practical implications: As the fraction of halloysite nanotubes is growing to 15%, structural changes in the powders of composite materials subjected to mechanical milling are reaching the set condition 3 times faster as compared to the matrix material. Originality/value: It has been confirmed that halloysite nanotubes can be applied as an effective reinforcement in the aluminium matrix composites. Deformation, grain size reduction and dispersion conduce to strengthening of the composite powders.

  3. Computer simulations of martensitic transformations in iron-nickel and nickel-aluminium alloys

    CERN Document Server

    Meyer, R J

    1998-01-01

    This thesis focuses on the martensitic transformations in iron-nickel and nickel-aluminum alloys. Molecular-dynamics simulations have been done, employing potentials based on the so-called embedded-atom method (EAM). These potentials were obtained by a fit of parameterized functions to experimental data of the elements iron, nickel, and aluminum as well as the intermetallic compound NiAl. Many aspects of the austenitic transformation in iron-nickel alloys and both, the martensitic and austenitic transformations, in nickel-aluminum alloys were reproduced well by the simulations. The results allow to draw conclusions on the reasons of differences and similarities in the behavior of both alloy systems.

  4. Development and UHV qualification of aluminium alloy vacuum chambers for transport line-2 of CTF-3, CERN

    International Nuclear Information System (INIS)

    CLIC Test Facility (CTF-3) at CERN is a project to demonstrate the concept of high frequency RF generation for the particle acceleration using a drive electron beam. 63 numbers of Aluminium alloy A6061T6 vacuum chambers for transport line-2 (TL-2) of CTF-3 were developed in RRCAT under joint collaboration between RRCAT and CERN. These chambers have Race Track (RT) and Cylindrical (CY) cross section. RT and CY, both type straight chambers as well as bent chambers (for the dipole magnets) were required for the TL-2. There were 22 numbers RT straight chamber, 31 numbers CY straight chamber, 5 numbers RT Bent chamber, 3 numbers CY bent chambers and 2 numbers CY Bent spare chambers. UHV Section was responsible for the qualification of demountable joints made of A6061T6 and also responsible for exhaustive UHV testing of these chambers. During the development, 5 numbers of different type of prototype chambers were fabricated and rigorously tested for leak tightness, qualification of demountable joints and desired ultimate vacuum using number of baking cycles. Helium mass spectrometer leak detector was utilised for leak detection at various stages for insuring the leak tightness better than1x10-10 mbar-l/s. For ultimate vacuum testing three setups were developed for the three types of different vacuum chambers. Each test setup consisted of Sputter Ion Pump, Turbo Molecular Pump, BA Gauge and Residual Gas Analyser. All these UHV setups were qualified for their ultimate vacuum in 10-10 mbar range. The arrangements were made such that, 4 to 8 straight chambers could be assembled and tested together in single cycle on each setup. Similar chambers were assembled with special Diamond shaped Aluminium seals with optimised sealing torque and leak tightness of -11 mbar-l/s was ensured. The aluminium chambers were baked at 150? where as the SS setups were baked at 250? for 24 hours and ultimate vacuum in the range of 10-10 mbar was achieved in all the sixteen test cycles. (author)

  5. Design, Analysis and Optimization of Three Aluminium Piston Alloys Using FEA

    OpenAIRE

    Ajay Raj Singh; Dr. Pushpendra Kumar Sharma

    2014-01-01

    This paper describes the stress distribution and thermal stresses of three different aluminum alloys piston by using finite element method (FEM). The parameters used for the simulation are operating gas pressure, temperature and material properties of piston. The specifications used for the study of these pistons belong to four stroke single cylinder engine of Bajaj Kawasaki motorcycle. This paper illustrates the procedure for analytical design of three aluminum alloy pistons ...

  6. Impact and Ballistic Resistance of a New Aluminium Alloy for Ship Construction Elements

    Directory of Open Access Journals (Sweden)

    Jurczak Wojciech

    2015-01-01

    Full Text Available The article presents results of examination of the new alloy 7020M intended to be used in shipbuilding. The examination concerned impact properties, verified on a numerical model, and the resistance to perforation (ballistic resistance. Impact and ballistic resistance tests aimed at increasing the operational safety of marine construc-tions to be made of this alloy under the threat of gunfire or explosion.

  7. Researches and studies regarding brazed aluminium alloys microstructure used in aeronautic industry

    OpenAIRE

    Dimitrescu, A.; Nit?oi, D. F.; Dobrota?, D.; Apostolescu, Z.

    2015-01-01

    Brazing is applied to the merge of the pieces which are most required, tensile strength of the solder can reach high values. By brazing there can be assembled pieces of most metals and ferrous and nonferrous alloys, with high melting temperature. This paper presents an analysis of the microstructure of materials from a brazed merge of aluminum alloy L103 which is often used to produce pieces of aeronautical industry. Brazing material was performed using several technologies, and after examina...

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

    Science.gov (United States)

    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.

  9. Hydrogen Absorption and Desorption Performance of magnesium-aluminium alloys produced by powder metallurgy

    International Nuclear Information System (INIS)

    The main scope of this study is investigating the hydrogen storage and desorption performance of Mg: Al (90:10), Mg17Al12 and Mg2Al3 alloys using a volumetric method. In the experiments, hydrogen pressure introduced into a reference volume was at approximately 20 Bar. Mg-Al alloys were prepared by a powder metallurgy technique. Pressing pressure levels of alloys were altered as 200, 400 and 600 MPa. Upon XRD patterns, after the pressing and sintering, beta-Mg2Al3 and Mg:Al(90:10) phases decomposed into gama-Mg17Al12, Mg and Al compositions. Gama-Mg17Al12 was the main phase in the hydrogen absorption/desorption process. The highest absorption of hydrogen was observed in the Mg:Al (90:10) alloys. The hydrogen desorption performance of the alloys decreased with the increase of absorption performance. Therefore the lowest desorption was observed in the Mg:Al (90:10) alloys. (author)

  10. Influences of pin profile and rotational speed of the tool on the formation of friction stir processing zone in AA2219 aluminium alloy

    International Nuclear Information System (INIS)

    AA2219 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio. Compared to the many fusion welding processes that are routinely used for joining structural aluminium alloys, 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. The welding parameters and tool pin profile play a major role in deciding the weld quality. In this investigation an attempt has been made to understand the influences of rotational speed and pin profile of the tool on friction stir processed (FSP) zone formation in AA2219 aluminium alloy. Five different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular and square) have been used to fabricate the joints at three different tool rotational speeds. The formation of FSP zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the FSP zone formation. From this investigation it is found that the square tool pin profile produces mechanically sound and metallurgically defect free welds compared to other tool pin profiles

  11. Assessment of corrosion resistance in liquid media of FeAl intermetallic phase based alloys with varied aluminium content

    Directory of Open Access Journals (Sweden)

    J. Cebulski

    2006-04-01

    Full Text Available Purpose: The paper presented results of corrosion resistance investigations with FeAl intermetallic phase matrix and different aluminium content (38%, 40% and 42%.Design/methodology/approach: In the corrosion research electrolyser, potentiostat „Solartron 1285” and computer with „CorrWare 2” software were used. Results of the research were worked out with „CorrView” software. The potential’s values were determined in relation to normal hydrogen electrode (NEW. The temperature of the solutions was kept on 21ºC level. The recording of potential/density of current - time curve was conducted for 300 s. Sample polarization ranges from potential smaller by 300 mV from normal potential to 0 mV in case of the test in 0.2% HCl solution as well as to 1500 mV in case of 3% H2SO4 solution. Rate of changing the potential amounted 10 mV/min in each case. Observations of the surface state were conducted using scanning electron microscope (JSM – 35 with magnifications from 30 to 1000.Findings: The results were showed that electrochemical corrosion conducted in 0,2% HCl and 3% H2SO4 solution depend on aluminium content. The best electrochemical corrosion resistance in 0.2%HCl have samples of Fe-38Al intermetallic phase based alloy and in 3% H2SO4 have Fe-40Al. It was confirmed by the lowest value of corrosion current density, low value of passive current density, pitting corrosion resistance much higher than in other samples.Research limitations/implications: The results of potentiodynamic research of alloy examined in 0.2% HCl solution are presented in table 1, these for 3% H2SO4 in table 2. Results of the potentiostatic and galvanostatic tests are presented in table 3. In figures 1, 2 the potentiodynamic curve are presented. Table 4 presents results of the surface state after corrosion tests. Figures 3 - 8 present surface state of the samples after corrosion research, which was observed using the scanning electron microscope.Originality/value: Corrosion resistance in liquid media of FeAl intermetallic phase.

  12. Fatigue crack growth rate behaviour of friction-stir aluminium alloy AA2024-T3 welds under transient thermal tensioning

    International Nuclear Information System (INIS)

    Highlights: • FSW enables unweldable aircraft material AA2024-T3 to be welded without cracking. • FSW applied to aircraft structure is required to have superior fatigue resistance. • Transient thermal tensioning (TTT) is being developed for stress relieving in FSW. • The fatigue crack growth rates of FSW joints under TTT are studied. - Abstract: Friction stir welding (FSW) has become a serious candidate technology to join metallic fuselage panels for the next generation of civil aircrafts. However, residual stress introduced during welding which subsequently affects fatigue performance is still a major problem that needs to be paid attention. The present investigation aims to improve fatigue crack growth resistance of friction stir aluminium alloy AA2024-T3 welds using transient thermal tensioning (TTT) treatment. In this investigation, aluminium alloy AA2024-T3 plates were joined using FSW process with and without TTT. The welding parameters used including tool rotation speed (Rt) and the plate travelling speed (v) were 1450 rpm and 30 mm/min respectively. The TTT treatments were carried out by heating both sides of friction stir weld line using moving electric heaters ahead of, beside and behind the tool at a heating temperature of 200 °C. Subsequently, a sequence of tests was carried out including microstructural examination, hardness measurement, tensile test and fatigue crack growth rate (FCGR) test in combination with fractography using scanning electron microscopy (SEM). The FCGR test was carried out using a constant amplitude fatigue experiment with stress ratio (R) of 0.1 and frequency (f) of 11 Hz whereas specimens used were centre-crack tension (CCT) type with the initial crack located at the weld nugget. Results of this investigation showed that at low ?K, typically below 9 MPa m0.5, the friction stir welds under TTT treatments lowered fatigue crack growth rate (da/dN) and the lowest (da/dN) was achieved as the heaters were located ahead of the tool. This improved weld fatigue performance was associated with stretching effect generated by movingly localised secondary heating which might alter the magnitude and distribution of residual stress in weld region and in a such condition, TTT seemed to act as local preheating

  13. Determination of crystalline texture in aluminium - uranium alloys by neutron diffraction

    International Nuclear Information System (INIS)

    Textures of hot-rolled aluminum-uranium alloys and of aluminum were determined by neutron diffraction. Sheets of alloys containing 8.0, 21.5 and 23.7 wt pct U, as well as pure aluminum, were obtained in a stepped rolling process, 15% reduction each step, 75% total reduction. During the rolling the temperature was 6000C. Alloys with low uranium contents are two phase systems in which an intermetallic compound UAl4, orthorhombic, is dispersed in a pure aluminum matrix. The addition of a few percent of Si in such alloys leads to the formation of UAl3, simple cubic, instead of UAl4. The Al -- 23.7 wt pct U alloy was prepared with 2,2 wt pct of Si. The results indicate that the texture of the matrix is more dependent on the uranium concentration than on the texture of the intermetallic phases. An improvement in the technique applied to texture measurements by using a sample fully bathed in the neutron beam is also presented. The method takes advantage of the low neutron absorption of the studied materials as well as of the neglibible variation in the multiple scattering which occurs in a conveniently shaped sample having a weakly developed texture. (Author)

  14. Biochemical analysis of the Hormoconis resinae fungal mycelium in the corrosion of aeronautical aluminium alloys

    International Nuclear Information System (INIS)

    Biochemical analyses of the Hormoconis resinae fungal mycelium would explain behaviour differences of corrosive and non-corrosive strains of Al and its aeronautical alloys. In previous works its aggressiveness had been studied through SEM-EDX surface analysis, electrochemical techniques and immersion testing. In this paper separation of the proteins of the mycelium produced by a non-corrosive strain and its culture along three generations was performed. cultures were prepared in batch in the presence and absence of pure Al and AA 2024, AA 7005 and AA 7075 alloys. The mycelia grown throughout the three generations increasingly recovered usual characteristics at the third replication, included their corrosiveness on Al and its alloys previously shown by all out strains. Among the bio-molecule fractions isolated and analysed during this preliminary study only the proteins revealed changes with the generation grown. When this fungal strain was cultured in the presence of alloy metal sheets electrophoresis of the protean fraction was correlative with the distinct mycelia behaviour observed, including corrosiveness on Al and its alloys. (Author) 30 refs

  15. SIMS investigations on the distribution of trace elements in modified aluminium-silicon-magnesium alloys

    International Nuclear Information System (INIS)

    Strontium modified aluminum-silicon cast alloys are well known for their outstanding mechanical properties as they combine excellent strength with good ductility that is due to a modification of brittle Si in the eutectic with traces of Sr (0.3-0.5 wt%). Although the level of Sr addition is very low, formation of ternary AlSiSr phases with deleterious effects on the ductility can take place. Consequently, there is a certain need of alternative modifying elements. Following the theory of Lu and Hellawell which predicts an optimal atomic size for good modification, Eu, which has an atomic radius close to that optimal size, was additionally used as a modifying element. This study presents SIMS (secondary ion mass spectrometer) investigations of the 3D-distributions of the main alloying and trace elements in Al-Si feedstock alloys for thixocasting modified with Sr and Eu, respectively. (author)

  16. Irradiation-induced creep and microstructural development in precipitation-hardened nickel-aluminium alloys

    International Nuclear Information System (INIS)

    Irradiation-induced creep in solid-solution Ni-8.5 at% AL and precipitation-hardened Ni-13.1 at% Al alloys was studied by bombarding miniaturized specimens with 6.2 MeV protons at 3000C under different tensile stresses. After irradiation transmission electron microscopic (TEM) investigations were made to observe the precipitate structure under irradiation for different experimental parameters. Moreover, the irradiation-induced changes in precipitate structure and changes of Al-concentrations in the matrix in Ni-13.1 at% Al alloys were studied by electrical resistivity measurements during irradiation. For comparison, the electrical resistivity of unirradiated specimens was also measured after thermal aging for different times. For correlation, TEM analysis was performed on irradiated and unirradiated aged specimens. Tensile tests on annealed and aged Ni-Al alloys were also done at various temperatures. (orig./RK)

  17. Effect of Cooling Rate on Mechanical Behaviour of Bulk Cast of A380 Aluminium Alloy

    Directory of Open Access Journals (Sweden)

    M.Mohandass

    2014-03-01

    Full Text Available One of the major factors that influence the mechanical properties of the cast alloy is the cooling rate during the solidification process. The objective of the present research work was to examine the effects of cooling rate on the mechanical properties of the A380 aluminum alloy cast. To study the variations in the mechanical properties with respect to cooling rate, the alloy was cast by conventional air-cooled and water-cooled methods. In this study the mechanical properties like tensile strength, compressive strength and impact strength of both air-cooled and water cooled cast specimens were tested and the results were compared. Increases in tensile and compressive strengths of the water cooled cast specimen have been encountered from the present work. This result reveals that increase in cooling rate leads to enhancement of the mechanical properties and also the disparity in them at various regions of bulk castings.

  18. Role of aluminium concentration on the structure behaviour of Cu-Al alloys

    International Nuclear Information System (INIS)

    Effect of Al(5, 10, 15 and 20)% on the structure behaviour of Cu-Al alloys was investigated by both microhardness measurements and optical microscopic investigations. Pure Cu was used for comparison. The analysis of the hardness-temperature curve shows a type of dependence which obeys an empirical exponential law, but consists of several distinguishable regions. For Cu 20% Al, one region is observed, and two regions for pure Cu, while for alloys of 5 and 10% Al concentration three regions were observed. The activation energy varies between 0.03 and 0.9 ev. for these regions, depending on the Al-concentration as well as the annealing temperature. The recrystallization temperature was found to increase with increasing Al-concentration. It was also observed that Cu-20% Al alloy is very hard and brittle owing to the formation of ?2 phase, and also to phase separation as being detected from optical microscopic investigations. (author). 22 refs, 3 figs

  19. Inhibition of Corrosion of Aluminium and its Alloys by Extracts of Green Inhibitors

    Scientific Electronic Library Online (English)

    M., Sangeetha; S., Rajendran; J., Sathiyabama; A., Krishnavenic.

    2013-01-01

    Full Text Available Aluminium is the most widely used non ferrous metal. It is very needful to prevent this metal from corrosion .Corrosion inhibitors are one of the widely used methods to control corrosion. The purpose of this paper is to make people aware of organic corrosion inhibitors. Organic inhibitors are mainly [...] present in natural products. It has been found that plant extracts and natural products show inhibition efficiency up to 98%. They are also non-toxic, eco-friendly, very cheaper. In the present work, natural products are used at various conditions and their inhibition efficiency is calculated by different methods; they obey various adsorption isotherms; the protective films formed by the inhibitors are analyzed by techniques such as electrochemical methods, FTIR, HPLC-RP, SEM, EDS.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Tristan O.; Pacher, Ulrich; Giesriegl, Ariane; Soyka, Lukas; Trettenhahn, Günter; Kautek, Wolfgang, E-mail: wolfgang.kautek@univie.ac.at

    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.