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Sample records for aa5052 aluminium alloy

  1. Electrochemical and DFT studies of quinoline derivatives on corrosion inhibition of AA5052 aluminium alloy in NaCl solution

    Science.gov (United States)

    Wang, Dapeng; Yang, Dong; Zhang, Daquan; Li, Kang; Gao, Lixin; Lin, Tong

    2015-12-01

    Two quinoline derivatives, 8-aminoquinoline (8-AQ) and 8-nitroquinoline (8-NQ), have been used as inhibitors to examine their corrosion protection effect on AA5052 aluminium alloy in 3% NaCl solution. The weight-loss and electrochemical measurement have indicated that 8-AQ and 8-NQ play as anodic inhibitor to retard the anodic electrochemical process. SEM/EDS analysis clearly shows that 8-AQ and 8-NQ form a protective film on the AA5052 alloy surface. Density functional theory (DFT) calculation confirmed the formation of strong hybridization between the p-orbital of reactive sites in the inhibitor molecules and the sp-orbital of the Al atom. 8-aminoquinoline and 8-nitroquinoline may be useful as effective corrosion inhibitors for aluminium alloys.

  2. 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 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

  3. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.C. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)], E-mail: wcliu@engr.uky.edu; Radhakrishnan, B. [Oak Ridge National Laboratory, P.O. Box 2008, MS-6140, Oak Ridge, TN 37831-6140 (United States); Li, Z. [Aleris International Inc., 1505 Bull Lea Road, Lexington, KY 40511 (United States); Morris, J.G. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)

    2008-01-15

    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 {beta} fiber rolling texture. After the third pass, a strong {beta} 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.

  6. 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.

  7. Texture evolution rate in continuous cast AA5052 aluminum alloy during single pass hot rolling

    International Nuclear Information System (INIS)

    Continuous cast AA5052 Al alloy slab was hot rolled by a single pass with entrance and exit temperatures of 482 deg. C and 400 deg. C, respectively. The thickness of the slab was reduced from 21.5 mm to 8.6 mm. The evolution of texture and microstructure during the rolling was investigated by X-ray diffraction, SEM and optical microscopy. It was found that the grain structure changed from equiaxed to elongated in shape in the alloy at a rolling reduction over 38%. With increase in rolling reduction, the ?-fiber texture was increased rapidly in the expense of the remainder component, while the rest of the texture components were only changed slightly during the hot rolling. The evolution of different texture components during the hot rolling process was quantified using modified Johnson-Mehl-Avrami-Kolmogorov-type equations. The corresponding evolution rates were also computed from these equations. Among the three main components (copper, brass and S) in ?-fiber, the copper component was the strongest, having the fastest evolution rate, and S the weakest, during hot rolling

  8. The optimum combination of tool rotation rate and traveling speed for obtaining the preferable corrosion behavior and mechanical properties of friction stir welded AA5052 aluminum alloy

    International Nuclear Information System (INIS)

    Highlights: • No reports available on study both corrosion–mechanical properties of FSWed AA5052. • Optimum corrosion and mechanical properties of SZ were attained at (? = 400, ? = 250). • An extremely fine grain structure was obtained in the SZ at (? = 400, ? = 250). • At (? = 400, ? = 250), further grain reinforcement in SZ accelerated the passivation. • Grain reinforcement in weld at (? = 400, ? = 250) improved the mechanical properties. - Abstract: This study attempts to find an optimum combination of the welding tool rotation rate (?) and traveling speed (?), concerning the corrosion and mechanical properties of Friction Stir Welded (FSWed) AA5052 Aluminum alloy. The effect of the tool speeds on the FSWed AA5052 are investigated via potentiodynamic polarization, open circuit potential (OCP) monitoring, test of the susceptibility to intergranular corrosion, weight loss, tension and micro-hardness tests. Optical microscope and Scanning Electron Microscopy (SEM) were employed for studying the morphology and analyzing the probable intergranular attacks. It was found that by increasing ? up to 200 mm/min at ? = 400 rpm, the microstructural evolution is in a way that the finer grain structure intensifies the anodic reactivity of the Stir Zone (SZ). At faster ? (about 250 mm/min), further grain reinforcement resulted in a predominant effect of passive film formation and thereby an unexpected high corrosion resistant SZ with a proper mechanical characteristics was attained

  9. 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

  10. 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)

  11. Silicon Alloying On Aluminium Based Alloy Surface

    International Nuclear Information System (INIS)

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  12. Cluster strengthening in aluminium alloys

    International Nuclear Information System (INIS)

    We consider the elastic effect of clusters and propose a size misfit strengthening model. Our approach is similar to solute strengthening, where the size misfit of clusters is assumed to be the sum of elementary atomic misfits. The proposed model is compared to the coherency strengthening model, and the results indicate that our model is applicable to clusters ?<1 nm in diameter. The prediction of the model is reasonably consistent with the reported experiments of aluminium alloys

  13. 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

  14. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    Susceptibility of aluminium and its alloys towards hydrogen embrittlement has been well established. Still a lot of confusion exists on the question of transport of hydrogen and its possible role in stress corrosion cracking. This paper reviews some of the fundamental properties of hydrogen in...... aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...

  15. 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.)

  16. Investigation & Analysis of Different Aluminium Alloys t

    Directory of Open Access Journals (Sweden)

    Nibedita Sethi*¹,

    2014-01-01

    Full Text Available Aluminium alloy LM-29, A-356 AND A-6060 was fabricated in sand casting method. Mach inability of aluminium alloy LM-29, A-356 AND A-6060 was investigated and evaluate the mach inability studying the different parameter such as cutting force, surface roughness, chip thickness, and power consumption during turning at different cutting speed and constant depth of cut and feed rate. In this paper also studies the mechanical properties means hardness, density and tensile strength of aluminium alloy LM-29,A-356 AND A-6060 by the help of tensile test ,hardness test and density test

  17. Alloys of uranium and aluminium with low aluminium content

    International Nuclear Information System (INIS)

    Uranium, as obtained after spinning in phase γ, 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 α) 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.)

  18. Fracture performance of high strength steels, aluminium and magnesium alloys during plastic deformation

    Directory of Open Access Journals (Sweden)

    Yu Haiyan

    2015-01-01

    Full Text Available A series of uniaxial tension tests were performed for 5052 and 6061 aluminum alloys, AZ31B magnesium alloy, TRIP600 and DP600 steels, to obtain a better understanding of their fracture performance. Scanning electron microscope (SEM observation of the microstructure evolution was conducted. The dimple structure, orientation relationship between the fracture surface and tensile direction, necking behavior were analyzed. The fracture mechanism and fracture mode of each material was discussed in detail. The results show that TRIP600 steel is subject to a typical inter-granular ductile fracture combined by shear fracture. DP600 steel belongs to mainly ductility mixed with normal fracture. Both 5052 and 6061 aluminum alloys are subject to a mixed ductility fracture and brittle fracture. AA5052 and AA6061 belong to a typical shear fracture and a normal fracture, respectively. Magnesium AZ31B is typical of a brittle fracture combined with normal fracture.

  19. Investigation & Analysis of Different Aluminium Alloys t

    OpenAIRE

    Nibedita Sethi*¹,; , Ajit Senapati²

    2014-01-01

    Aluminium alloy LM-29, A-356 AND A-6060 was fabricated in sand casting method. Mach inability of aluminium alloy LM-29, A-356 AND A-6060 was investigated and evaluate the mach inability studying the different parameter such as cutting force, surface roughness, chip thickness, and power consumption during turning at different cutting speed and constant depth of cut and feed rate. In this paper also studies the mechanical properties means hardness, density and tensile strength o...

  20. Scandium alloying of aluminium copper-containing alloys

    International Nuclear Information System (INIS)

    Scandium alloyed commercial alloys on the basis of the Al-Mg, Al-Zn-Mg, Al-Mg-Li systems have been worked out. Scandium alloying of aluminium alloys containing copper as alloyng component should be realized with caution, since scandium binds copper into a chemical compound. As a result strength poroperties of semifinished products, as well as their ductility and fracture toughness, deteriorate due to increase in the volumetric part of excess phases. Conditions of scandium alloying of copper-containing aluminium alloys have been defined. 9 refs.; 5 figs.; 4 tabs

  1. 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)

  2. Alloys oxidation of aluminium-scandium system

    International Nuclear Information System (INIS)

    Alloys and compounds of rare earth metals with aluminium thanks to their high corrosion stability, durability and small specific weight find to apply in various new techniques. On the base of carried out investigation it could be recommend as de oxidizing and alloying compositions containing 15-50 % of scandium as in possession of minimal oxidation

  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. Roll casting of 5182 aluminium alloy

    Directory of Open Access Journals (Sweden)

    T. Haga

    2009-06-01

    Full Text Available Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed. 5182 could be cast at 10 times higher speed than a conventional twin roll caster for aluminium alloy. 5182 could be cast by the mild steel roll using no-parting material without sticking.Research limitations/implications: is that ability of casting of the wide strip, that is wider than 600 mm, could not be investigated.Practical implications: 600 mm-width 5182 strip could be cast and this width is enough for some structural parts. 5182 could be cast into the strip at high productivity and low energy using the economy equipment and no-consumable good.Originality/value: The method to make economy sheet metal of aluminium alloy is imported. The economy alloy and economy process are essential to get economy aluminium alloy sheet.

  5. 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.

  6. Potential for improved mechanical properties in cast aluminium alloys

    OpenAIRE

    Bäckman, Jonas; Svensson, Ingvar L

    1999-01-01

    The aim of this work is to investigate the potential to improve the mechanical properties of some aluminium alloys, in order to obtain castings with optimum properties. Experiments have been made with pure aluminium, aluminium alloyed with 1% Si and 0,9% Mg and four aluminium cast alloys with 7-12% Si and various amounts of iron, magnesium, copper and manganese. To achieve the best possible solidification, gradient solidification technology of tensile specimen has been used, in order to explo...

  7. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

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

    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......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...

  8. 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.

  9. Alloys of uranium and aluminium with low aluminium content; Alliages uranium-aluminium a faible teneur en aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Cabane, G.; Englander, M.; Lehmann, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Uranium, as obtained after spinning in phase {gamma}, 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 {alpha}) 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 (UAl{sub 2}) 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 UAl{sub 2} 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.)

  10. Mechanical behaviour of aluminium-lithium alloys

    Indian Academy of Sciences (India)

    N Eswara Prasad; A A Gokhale; P Rama Rao

    2003-02-01

    Aluminium-lithium alloys hold promise of providing a breakthrough response to the crying need for lightweight alloys for use as structurals in aerospace applications. Considerable worldwide research has gone into developing a range of these alloys over the last three decades. As a result, substantial understanding has been developed of the microstructure-based micromechanisms of strengthening, of fatigue and fracture as well as of anisotropy in mechanical properties. However, these alloys have not yet greatly displaced the conventionally used denser Al alloys on account of their poorer ductility, fracture toughness and low cycle fatigue resistance. This review aims to summarise the work pertaining to study of structure and mechanical properties with a view to indicate the directions that have been and can be pursued to overcome property limitations.

  11. Neutron irradiation of dilute aluminium alloys

    International Nuclear Information System (INIS)

    Aluminium alloys containing up to 0.4% silicon and 0.1% indium were irradiated at various doses up to 1021n/cm2 (E>0.1 MeV) at pile temperature. Indium was found to enhance and silicon to suppress the nucleation of voids. The reasons for this are discussed in terms of possible nucleation processes. The changes in 0.2% proof stress were correlated with the change in microstructure. (Auth.)

  12. FSW characterization of 6082 aluminium alloys sheets

    OpenAIRE

    K. Mroczka; A. Pietras

    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...

  13. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    N Vidhya Sagar; K S Anand; A C Mithun; K Srinivasan

    2006-12-01

    Friction factor has been determined for CP aluminium and aluminium–zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits sticking whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier than that of CP aluminium at 773 K. As zinc content increases up to 10 wt% the friction factor decreases up to 0.02.

  14. Study of fatigue behaviour of 7475 aluminium alloy

    Indian Academy of Sciences (India)

    B B Verma; J D Atkinson; M Kumar

    2001-04-01

    Fatigue properties of a thermomechanically treated 7475 aluminium alloy have been studied in the present investigation. The alloy exhibited superior fatigue life compared to conventional structural aluminium alloys and comparable stage II crack growth rate. It was also noticed that the fatigue crack initiated from a surface grain and the crack extension was dominated by ductile striations. Analysis also revealed that this alloy possessed fracture toughness and tensile properties superior to that noticed with other structural aluminium alloys. Therefore the use of this alloy can safely reduce the overall weight of the aircraft.

  15. 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

  16. Characterisation of electron beam welded aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cam, G.; Ventzke, V.; Dos Santos, J.F.; Kocak, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung; Jennequin, G.; Gonthier-Maurin, P. [CNIM, Zone Industrielle de Bregaillon, La Seyne-Sur-Mer (France)

    2001-07-01

    Electron beam (EB) welding was performed on three different aluminium alloys, namely alloys 2024, 5005, and 6061 (plate thickness 5 mm except alloy 5005 which was 3 mm in thickness), to establish the local microstructure-property relationships that would satisfy the service requirements for an electron beam welded aluminium alloy component with weld zone strength undermatching. Microstructural characterisation of the weld metals was carried out by optical and scanning electron microscopy. A very low level of porosity was observed in all EB welds owing to surface cleaning before welding and the vacuum environment of the EB welding process. Extensive microhardness measurements were also conducted in the weld regions of the joints. Global tensile properties and fracture toughness properties (in terms of crack tip opening displacement, CTOD) of the EB joints were determined at room temperature. The effects of strength mismatch and local microstructure on fracture toughness of the EB joints are discussed. The purpose of the present paper is to report the partial results of the European Brite-Euram project ASPOW (assessment of quality of power beam weld joints; BRPR-CT95-0021), which has been undertaken predominantly by industrial companies to establish a European framework for destructive and non-destructive testing and assessment criteria for laser and electron beam welds of over 20 metallic materials. (orig.)

  17. Fluidity of Aluminium Foundry Alloys

    OpenAIRE

    Di Sabatino, Marisa

    2007-01-01

    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...

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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...

  3. 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

  4. Influence of aluminium alloy type on dissimilar friction stir lap welding of aluminium to copper

    OpenAIRE

    Galvão, I; Verdera, D.; Gesto, D; Loureiro, A.; Rodrigues, D. M.

    2013-01-01

    A heat-treatable (AA 6082) and a non-heat treatable (AA 5083) aluminium alloys were friction stir lap welded to copper using the same welding parameters. Macro and microscopic analysis of the welds enabled to detect important differences in welding results, according to the aluminium alloy type. Whereas important internal defects, resulting from ineffective materials mixing, were detected for the AA 5083/copper welds, a relatively uniform material mixing was detected in the AA 6082/copper wel...

  5. Examples of liquid metal embrittlement in industrial aluminium alloys

    International Nuclear Information System (INIS)

    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)

  6. Examples of liquiq metal embrittlement in industrial aluminium alloys

    Science.gov (United States)

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

    2002-09-01

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

  7. 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)

  8. 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.

  9. Niobium and aluminium segregation in nickel alloy welds

    International Nuclear Information System (INIS)

    The segregation of niobium and aluminium in nickel-niobium and nickel-aluminium binary alloy joints has been studied. The segregation evaluations according to estimation patterns and those of X-ray microspectral analysis of element distribution were compared. A very clearly marked niobium tendency to segregation has been found in nickel binary alloy joints. Aluminium shows an insignificant segregation. Niobium, to a great degree, supresses grain boundary migration and intercrystalline sliding, and reduces hot cracking resistance. Nb and Al segregation data are shown to be in a good agreement with the theoretical ones

  10. 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.

  11. 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.

  12. Computer modelling of age hardening for cast aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Linda; Ferguson, W George, E-mail: ywu034@aucklanduni.ac.nz [Department of Chemical and Materials Engineering, the University of Auckland, Private Bag 92019, Auckland (New Zealand)

    2009-08-15

    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.

  13. Application of Pre-heating to Improve the Consistency and Quality in AA5052 Resistance Spot Welding

    Science.gov (United States)

    Luo, Zhen; Ao, Sansan; Chao, Yuh Jin; Cui, Xuetuan; Li, Yang; Lin, Ye

    2015-09-01

    Making consistent resistance spot welds of aluminum alloy with good quality and at high volume has several obstacles in automotive industry. One of the difficult issues arises from the presence of a tough non-conducting oxide film on the aluminum sheet surface. The oxide film develops over time and often is non-uniform across the surface of the aluminum alloy sheet, which makes the contact resistance characteristics irregular at the faying interface during welding. The consistency in quality of the final spot welds is therefore problematic to control. To suppress the effect of the irregular oxide film on the spot weld quality, application of a pre-heating treatment in the welding schedule for aluminum alloy 5052 is investigated in this present work. The current level of the pre-heating required to reduce the scatter of the contact resistance at the W/W (workpiece-to-workpiece) faying interface is quantified experimentally. The results indicate that the contact resistance at the W/W faying interface with a pre-heating treatment becomes much consistent and can be reduced by two orders of magnitude. Having the uncertain variation of the contact resistance at the W/W faying surface virtually reduced or removed, the quality of the spot welds in terms of the peak load and nugget diameter is examined and shows a great improvement. The proposed method may provide a robust method for high-volume spot welding of aluminum alloy sheets in auto industry.

  14. Application of Pre-heating to Improve the Consistency and Quality in AA5052 Resistance Spot Welding

    Science.gov (United States)

    Luo, Zhen; Ao, Sansan; Chao, Yuh Jin; Cui, Xuetuan; Li, Yang; Lin, Ye

    2015-10-01

    Making consistent resistance spot welds of aluminum alloy with good quality and at high volume has several obstacles in automotive industry. One of the difficult issues arises from the presence of a tough non-conducting oxide film on the aluminum sheet surface. The oxide film develops over time and often is non-uniform across the surface of the aluminum alloy sheet, which makes the contact resistance characteristics irregular at the faying interface during welding. The consistency in quality of the final spot welds is therefore problematic to control. To suppress the effect of the irregular oxide film on the spot weld quality, application of a pre-heating treatment in the welding schedule for aluminum alloy 5052 is investigated in this present work. The current level of the pre-heating required to reduce the scatter of the contact resistance at the W/W (workpiece-to-workpiece) faying interface is quantified experimentally. The results indicate that the contact resistance at the W/W faying interface with a pre-heating treatment becomes much consistent and can be reduced by two orders of magnitude. Having the uncertain variation of the contact resistance at the W/W faying surface virtually reduced or removed, the quality of the spot welds in terms of the peak load and nugget diameter is examined and shows a great improvement. The proposed method may provide a robust method for high-volume spot welding of aluminum alloy sheets in auto industry.

  15. 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.

  16. Dilute aluminium alloys: their potential in superconducting devices

    International Nuclear Information System (INIS)

    Until an inexpensive, lightweight, high strength, low resistivity stabilizing material is developed, the full potentialities of large superconductive devices will not be realized. The use of aluminium as a replacement for copper, which is normally used at the moment, would solve both the cost and the materials shortage problems, if a high strength aluminium alloy could be developed -provided the alloy had a resistance ratio (rhosub(273 K)/rhosub(4.2 K)) equivalent to that of OFHC copper. This paper presents an assessment of the possibilities of developing such an alloy. The factors which influence yield strength and resistivity are outlined and a series of experiments are described. These experiments, conducted on dilute aluminium - gold alloys describe the process by which optimization of strength and resistivity can be achieved. (author)

  17. 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...

  18. Use of acoustic energy in sand casting of aluminium alloys

    OpenAIRE

    Puga, Hélder; Barbosa, J.; Oliveira, Joana

    2013-01-01

    During the last years, some researchers have focused the development of ultrasonic microstructure refinement /modification techniques of die-casting aluminium alloys, to improve their properties. The developed techniques are highly efficient when applied to the die-casting process, but their capability with sand and ceramic moulding are unknown. Sand/ceramic aluminium castings are prone to coarse microstructure, porosities and inclusions due to low cooling rates and turbulent gravity pouri...

  19. Stress corrosion cracking of silver-bombarded aluminium alloys

    International Nuclear Information System (INIS)

    Aluminium alloys of the type used in the aircraft industry are often subject to stress corrosion cracking. Bulk alloying with small quantities of silver improves the resistance of the alloys against this type of corrosion. (1-5) X 1016 Ag+ ions cm-2 at 150 keV were implanted into the Al-Zn-Mg-Cu alloy test specimen. The alloys were tested in 3% or 3.5% NaCl solution at 21 and 800C under constant strain rate or under a constant load. (Auth.)

  20. Failures of dies for die-casting of aluminium alloys

    OpenAIRE

    Kosec, B.

    2008-01-01

    Die-casting dies for casting of aluminum alloys fail because of a great number of different and simultaneously operating factors. Material selection, die design, and thermal stress fatigue generated by the cyclic working process (heat checking), as well as to low and inhomogeneous initial die temperature contribute to the failures and cracks formation on/in dies for die-casting of aluminium alloys. In the frame of the presented investigation work the intensity and homogeneity of the temperatu...

  1. 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)

  2. Extractive-photometric determination of boron in aluminium alloys

    International Nuclear Information System (INIS)

    A method for determination of boron in aluminium alloys without preliminary isolation is developed. The method is based on extraction of the ion associate of the tetrafluoroborate ion with brilliant green by butyl acetate. The interval of determinable concentrations of boron is 0.1-0.8 ?g/ml

  3. Influence of alloying elements and etching treatment on the passivating films formed on aluminium alloys

    OpenAIRE

    Feliu Jr., S.; Bartolomé, Mª. J.

    2007-01-01

    This paper studies the characteristics of aluminium oxide layers present on the surface of commercial aluminium specimens after thermomechanical processing and after subsequent etching in an alkaline solution, highlighting the main differences observed.Anattempt ismade to establishpossible relationships between alloying elements and the characteristics of these layers

  4. 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.

  5. 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.

  6. High-temperature and electrochemical corrosion of aluminium-scandium alloys

    International Nuclear Information System (INIS)

    The methods of gravimetry and thermogravimetry in isothermal and polithermal conditions are used to shown that scandium and aluminium additions decrease aluminium oxidation rate. The performed assessment of corrosion-electrochemical properties of the above alloys points to the appropriateness of low alloying of aluminium with scandium to improve corrosion resistance of the former. 8 refs.; 4 figs.; 3 tabs

  7. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    K T Kashyap; T Chandrashekar

    2001-08-01

    Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific literature. The nucleant effects i.e. which particle and its characteristics nucleate -Al, has been the subject of intensive research. Lately the solute effect i.e. the effect of dissolved titanium on grain refinement, has come into forefront of grain refinement research. The present paper attempts to review the literature on the nucleant effects and solute effects on grain refinement and addresses the importance of dissolved titanium in promoting nucleation of -Al on nucleant particles.

  8. The effects of radiation on aluminium alloys in the core of energy nuclear reactors

    International Nuclear Information System (INIS)

    One of the attractive directions in the worldwide practice of nuclear installations is the replacement of expensive zirconium alloy with more cheap materials, particularly aluminium allo. For Heat Supply Nuclear Plants (HSNP) with approximately 473 K core temperatures, the use of heat-resistant aluminium alloys seems to be reasonable. The present work is concerned with the studies on radiation effects on aluminium alloy, and interaction between the alloy and coolant in the reactor core. (author). 2 refs., 3 figs., 1 tab

  9. 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.

  10. 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

  11. Gas accumulation at grain boundaries during 800 MeV proton irradiation of aluminium and aluminium-alloys

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Horsewell, Andy; Sommer, W. F.; Lohmann, W.

    1986-01-01

    Samples of pure aluminium (99.9999%) and commercial Al-2.7%Mg(AlMg3) and Al-1.1%Mg-0.5%Si(Al6061) alloys were irradiated with 800 MeV protons at the Los Alamos Meson Physics Facility (LAMPF) at a temperature between 40-100°C to a maximum dose of 0.2 dpa. Transmission electron microscopy (TEM) showed a complete absence of voids or bubbles in the grain interiors of the aluminium and the aluminium-alloys. Bubbles were clearly visible by TEM at grain boundaries in pure Al and the AlMg3 alloy; but bu...

  12. On the effect of heat and metallurgical treatments on the thermal conductivity of cast aluminium alloys

    OpenAIRE

    Rauta, Veijo

    2015-01-01

    In this research the goal was to find possible ways, such as optimization of alloy composition, heat and melt treatments, to improve thermal conductivity of aluminium castings, especially aluminium die castings. The main target was to increase the thermal conductivity (TC) of aluminium die cast parts up to 190 W/mK or to the same level as extruded aluminium wrought alloys have and the goal was reached. Casting methods were die casting, sand, permanent mould and rheocasting. Studied alumini...

  13. Vibrational strength behaviour of fiber-reinforced aluminium alloys. Schwingfestigkeitsverhalten faserverstaerkter Aluminium-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, K.; Trautmann, K.H. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Werkstoff-Forschung); Girot, F. (Bordeaux Univ., 33 (France))

    1990-01-01

    The mechanical properties at monotonous tensile and compressive stress and fatigue stress (R=0.1 and R=-1) were studied in an aluminium-2.5% lithium alloy reinforced unidirectionally with 30% Al{sub 2}O{sub 3} fibres. Considerably higher tensile and compressive stresses were achieved at monotonous loading. The fatigue lives achieved were higher than those of unreinforced Al alloys. Cyclic solidification was recorded during fatigue loading. Significant differential features were found at the fracture areas of the fatigue samples compared to the static samples. (orig.).

  14. TORSIONAL DEFORMATION AND FATIGUE BEHAVIOUR OF 6061 ALUMINIUM ALLOY

    Directory of Open Access Journals (Sweden)

    marini marno

    2012-02-01

    Full Text Available Torsional deformation and fatigue behaviour of both solid and thin-walled tubular specimens were made from as-received and heat treated 6061 aluminium alloy were studied. 6061 aluminium alloy have been widely used as a candidate material in automobile, aerospace, aircraft and structural application because of their superior mechanical properties such as high strength to weight ratio, good ductility and others. The differences in cyclic deformation and fatigue behaviours between round and solid specimens where a stress gradient exist, and thin-walled tubular specimens where a uniform stress state is commonly assumed, are also discussed. Von Mises and Tresca criteria has been used to predict the monotonic and cyclic deformation curve and compared to the torsional data obtained from the experiment. The S-N curve was used to present and evaluate the fatigue life of the specimens. Through fractographic analysis, failure criteria of fracture surfaces were observed and discussed. 

  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. Oxidation of solid aluminium-magnesium alloy doped by scandium

    International Nuclear Information System (INIS)

    The oxidation of solid aluminium-magnesium alloy with scandium was studied by means of thermogravimetry method. The kinetic and energy parameters of oxidation process were defined. The kinetics of oxidation was studied by means of thermogravimetry method. The apparent activation energy was defined as well. The products of oxidation were studied by means of X-ray analysis method. It was shown that the main products of oxidation were ?-Al2O3 and Mg O.

  17. 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...

  18. Research progress of aluminium alloy endplates for PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yu.; Hou, Junbo [Fuel Cell system and Engineering Laboratory, Dalian Institute of Chemical and Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Hou, Ming; Yan, Xiqiang; Luo, Xiaokuan; Shao, Zhigang; Yi, Baolian [Fuel Cell system and Engineering Laboratory, Dalian Institute of Chemical and Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2007-04-15

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

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

    OpenAIRE

    Prabhkiran Kaur; D.K. Dwivedi; P.M. Pathak; Sunil Kumar

    2014-01-01

    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 ear...

  1. PROCESS CAPABILITY STUDY OF A RAPID CASTING SOLUTION FOR ALUMINIUM ALLOYS USING THREE-DIMENSIONAL PRINTING

    OpenAIRE

    Singh, R.

    2011-01-01

    In the present work, the best shell wall thickness of a mould cavity was investigated in a process capability study of a rapid casting solution for aluminium alloys using three-dimensional printing (3DP). Starting from the identification of a component/benchmark, an aluminium-alloy casting prototype was produced with different shell wall thicknesses by three dimensional printing. The results of the study suggest that, at the best shell wall thickness (5 mm) for aluminium alloys, the rapid cas...

  2. Asymmetric rolling of 5182 aluminium alloy and interstitial free steel sheets

    OpenAIRE

    Tamimi, Saeed

    2013-01-01

    This Ph.D. research focuses on asymmetric rolling (ASR), as an alternative method for improving mechanical responses of aluminium-magnesium alloy and interstitial free (IF) steel regarding industrial requirements. Aluminium alloys are attractive materials in various industries due to their appropriate properties such as low density and corrosion resistance; however, their low formability has limited their applications. As formability of aluminium alloys can be improved throu...

  3. Aluminium alloys in sulfuric acid. Pt. 2: Aluminium-oxygen cells

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.; Holzer, F.; Desilvestro, J.; Haas, O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-12-01

    Aluminium alloys were tested in Al/O{sub 2} cells with strongly acidic electrolytes containing minor amounts of chloride ions. The faradaic efficiency, the maximum discharge capacity and the peak power of various Al/O{sub 2} cells were evaluated. The temperature dependence of the faradaic efficiency was measured for an Al/O{sub 2} cell over the temperature range from 15 to 50{sup o}C. With a zinc-containing aluminium alloy, a faradaic efficiency of 84% and a cell voltage of 1.6 V at open circuit and 0.7 V at 100 mA cm{sup -2} could be reached. The highest peak power 120 mW cm{sup -2}, was obtained with an Al-Zn/Sn alloy. On the basis of the solubility of the anode products in the electrolyte, a limiting specific energy of 70 Wh kg{sup -1} was estimated. The cell voltage depends on the Al-alloys and on the catalyst used in the oxygen electrode. The cell voltage could be increased by about 200 mV when replacing the Pt-catalysed oxygen electrode with a noble-metal-free (CoCAA/DCD) electrode. (author)

  4. The kinetics of oxidation of solid aluminium-lithium alloys alloyed by alkali earth metals

    International Nuclear Information System (INIS)

    For the investigation of influence of alkali earth metals on kinetics of oxidation of aluminium-lithium alloys by authors was synthesised the series of alloys with containing of alkali earth metals from 0.01 til 0.01% on mass. For the investigation of kinetics oxidation of above mentioned alloys applied thermogravimetric method. Investigation was carried out in the air atmosphere at temperature 723 and 793 K

  5. Gas accumulation at grain boundaries during 800 MeV proton irradiation of aluminium and aluminium-alloys

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Horsewell, Andy; Sommer, W. F.; Lohmann, W.

    Samples of pure aluminium (99.9999%) and commercial Al-2.7%Mg(AlMg3) and Al-1.1%Mg-0.5%Si(Al6061) alloys were irradiated with 800 MeV protons at the Los Alamos Meson Physics Facility (LAMPF) at a temperature between 40-100°C to a maximum dose of 0.2 dpa. Transmission electron microscopy (TEM......) showed a complete absence of voids or bubbles in the grain interiors of the aluminium and the aluminium-alloys. Bubbles were clearly visible by TEM at grain boundaries in pure Al and the AlMg3 alloy; but bubbles were not visible in the Al6061 alloy. The bubble density in the AlMg3 alloy was considerably...

  6. Influence of nanoporous structure on mechanical strength of aluminium and aluminium alloy adhesive structural joints

    Energy Technology Data Exchange (ETDEWEB)

    Spadaro, C; Dispenza, C; Sunseri, C [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita degli Studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2006-08-23

    The influence of surface treatments on the mechanical strength of adhesive joints was investigated. The attention was focused on AA2024 alloy because it is extensively used in both the automotive and aerospace industries. Adhesive joints fabricated with pure aluminium were also investigated in order to evidence possible differences in the surface features after identical treatments. Before joining with a commercial epoxy adhesive, metal substrates were subjected to different kinds of treatment and the surfaces were characterized by SEM analysis. The formation of a microporous surface in the AA2024 alloy, upon etching and anodizing, is discussed on the basis of the role of the intermetallic particles and their electrochemical behaviour with respect to the aluminium matrix. Moreover, nanostructured porous oxide layers on both type of substrate were also formed, as a consequence of the anodizing process. Differences in their morphologies were revealed as a function of both the applied voltage and the presence of alloying elements. On this basis, an explanation of the different values of fracture energy measured by means of T-peel tests carried out on the corresponding joints was attempted.

  7. 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.

  8. Development of promising aluminium alloy for bases of rigid magnetic disks with high recording density

    International Nuclear Information System (INIS)

    A study was made into the influence of additional alloying of the AMS aluminium base alloys on the structure of blanks for magnetic disk bases. A new alloy Amadis is developed as a result of researches. Comparison with commercial products from AMS and 1541 alloys confirmed high structural parameter of the new alloy. 12 refs., 5 figs., 3 tabs

  9. 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

  10. Hot Deformation Of 6xxx Series Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Mrówka-Nowotnik G.

    2015-06-01

    Full Text Available The hot deformation behavior of the 6xxx aluminum alloys was investigated by compression tests in the temperature range 100°C-375°C and strain rate range 10?4s?1 and 4×10?4s?1 using dilatometer DIL 805 BÄHR Thermoanalyse equipped with accessory attachment deformation allows the process to execute thermoplastic in vacuum and inert gas atmosphere. Associated microstructural changes of characteristic states of examined alloys were studied by using the transmission electron microscope (TEM. The results show that the stress level decreases with increasing deformation temperature and deformation rate. And was also found that the activation energy Q strongly depends on both, the temperature and rate of deformation. The results of TEM observation showing that the dynamic flow softening is mainly as the result of dynamic recovery and recrystallization of 6xxx aluminium alloys.

  11. Molten aluminium alloy fuel fragmentation experiments

    International Nuclear Information System (INIS)

    Experiments were conducted in which streams of molten aluminum alloys were injected into a 1.2-m deep pool of water. The parameters varied were (i) injectant material (8001 aluminum alloy and 12.3 wt% U-87.7 wt% Al), (ii) melt superheat (0 to 50 K), (iii) water temperature (313, 343 and 373 K) and (iv) size and geometry of the pour stream (5, 10 and 20 mm diameter circular and 57 mm annular). The pour stream fragmentation was dominated by surface tension with large particles (?30 mm) being formed from varicose wave breakup of the 10-mm circular pours and from the annular flow off a 57 mm diameter tube. The fragments produced by the 5 mm circular jet were smaller (?10 mm), and the 20 mm jet which underwent sinuous wave breakup produced ?100 mm fragments. The fragments froze in 313 K water to form large solid particles with high voidage which would be readily coolable. However, in water ?343 K the melt fragments did not freeze during their transit through 1.2 m of water and agglomerated into a melt pool at the bottom of the vessel. (orig.)

  12. ''Ventilated brake discs manufactured in aluminium matrix composites and hypereutectic aluminium alloys''

    Energy Technology Data Exchange (ETDEWEB)

    Goni, J.; Coleto, J.; Eguizabal, P.; Rubio, A. [Fundacion INASMET, San Sebastian (Spain); Garcia, A.; Sanchez, J. [Inst. Univ. de investigacion del Automovil, Madrid (Spain)

    2003-07-01

    Two different aluminium alloy materials have been used to produce ventilated brake discs, on one hand, AS17G0.6 hypereutectic alloy and on the other hand, AS7G0.6 reinforced with 20% in wt. of SiC particles. The casting production technique used has been low pressure casting (LPC) and some of the brake discs have been heat treated using a T6 treatment. Once the ventilated brake discs were produced and machined, they were tested in a dynamometer in order to compare the performance under service conditions of the aluminium alloy and grey cast iron (GCI) discs currently used in the market. (orig.)

  13. Validation and realization of advanced aluminium alloy coatings by thermal spraying process

    International Nuclear Information System (INIS)

    A process on how to apply new aluminium alloys by thermal spray coating is discussed. Aluminium-based high alloying compositions were selected as coating materials to protect soft substrates against friction, abrasion and others. The beneficial properties of these new alloys are its high hardness and low friction coefficient. The atomic structures of the alloys are either quasi-crystalline and/or crystalline, and in the latter case the structures obtained have a close structural relation with quasi-crystals

  14. 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.

  15. Secondary ageing in an aluminium alloy 7050

    International Nuclear Information System (INIS)

    Secondary precipitation takes place in alloy 7050 at 65 deg. C after underageing at 130 deg. C and quenching (T6I4-65 temper) and results in a significantly increased number density of the ?' platelets, the precipitates also formed in the T6 temper. The modified microstructure results in tensile properties comparable to that of the T6 temper, but with significantly improved fracture toughness. A combined transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) study has shown that secondary ageing at 65 deg. C results in evolution of the GPI zones formed during underageing into the ?' phase. Ageing at 65 deg. C alone results in the formation of GPII zones, which provide lesser strengthening than the ?' platelets. The DSC study revealed six exothermic reactions corresponding to the formation of six different types of precipitate during the DSC scan

  16. Anodization of cast aluminium alloys produced by different casting methods

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2008-08-01

    Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

  17. 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)

  18. Microplasma anodization of aluminium and its copper-containing alloy in potassium hyxafluorozirconate solution

    International Nuclear Information System (INIS)

    Specific features of oxide coating formation on the surface of aluminium and its copper-conaining alloy in potassium hexafluorozirconate solution have been studied under conditions of microplasma anodization. Potentiality of producing coatings on the surface of aluminium and its alloys, which consist of zirconium dioxide both of its crystalline modifications in combination with amorphous aluminium oxide and small amount of its crystal phase, has been considered by the method of microplasma anodization. Refs. 7, figs. 2

  19. Simultaneous spectrophotometric determination of titanium and scandium in aluminium alloys

    International Nuclear Information System (INIS)

    A method is suggested simultaneous spectrophotometric determination of titanium and scandium in aluminium-base alloys with the Ti>=0.01% and Sc>=0.002% concentration. The method is based on the formation at pH 3.8-4.0 of a complex via the reaction of arsenazo (3) with Ti(4) ions in the presence of sodium molybdate and complexone 3. The latter is introduced for the Sc-Mo-arsenazo 3 complex destruction. Ions of Fe, Ni, Cr, Be, Mg, Zn may be present is the amount of up to 20 mg in the volume being measured by photometry

  20. 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.

  1. Role of acidic chemistries in steam treatment of aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl

    2015-01-01

    The effect of acidic chemistry on the accelerated growth of oxide on aluminium alloys Peraluman 706TM and AA6060 under exposure to high temperature steam was investigated. Studied chemistries were based on citrates and phosphates. Results showed that the presence of citrate and phosphate anions initiate doxide growth at the intermetallic particles while growth and corrosion performance of oxide was found tobe a function of anions type and their concentration. Further, steam treatment with phosphates exhibited better performance under acetic acid salt spray and filiform corrosion test whereas delay in powder coating resulted in 1.5–3 times inferior performance.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cambronero, L.E.G.; Ruiz-Roman, J.M. [Grupo de Materiales Hibridos, ETSIM-UPM, Madrid, Rios Rosas 21, 28003 Madrid (Spain); Canadas, I.; Martinez, D. [Plataforma Solar de Almeria, CIEMAT, P.O. Box 22, 04200 Tabernas (Almeria) (Spain)

    2010-06-15

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

  3. Characterization of AA7050 aluminium alloy processed by ECAP

    International Nuclear Information System (INIS)

    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 ? phase, which evolves to equiaxial morphology as the number of passes increases. (author)

  4. Slip lines in scandium and lithium containing aluminium alloys

    International Nuclear Information System (INIS)

    Intensive slip lines in cold rolled sheets of scandium or lithium containing aluminium base alloys are under study. Slip lines are shown to be the places of concentrated shear strain which arise due to the occurrence of secondary ?'(Al3Li) and Al3Sc particles completely coherent to the matrix. The formation of slip lines has a detrimental effect on cold rolled sheet mechanical properties after heat hardening. To avoid the appearance of slip lines it is necessary to roll sheets with low reductions in area and to choose appropriate conditions of intermediate heat treatments. 5 refs., 5 figs., 2 tabs

  5. Precipitation kinetics of Si in aluminium alloys

    International Nuclear Information System (INIS)

    The precipitation kinetics of Si in an Al-1.7 wt.%Si alloy after different thermal treatments has been studied by means of transmission electron microscopy (TEM), dilatometry and differential scanning calorimetry (DSC). The results obtained are explained by a model based on simple nucleation and growth/dissolution laws and are compared with measured precipitate size distributions. The evolution of precipitates in water-quenched samples during linear heating depicts the exothermic formation of platelets and globular Si precipitates (200-300 deg. C). The endothermal dissolution of Si platelets starts at lower temperatures than that of the globular precipitates. Coarsening and finally dissolution of globular precipitates is observed with increasing temperature. Samples slowly cooled from the solution treatment temperature present mostly globular precipitates, which are nucleated during cooling. Here, an exothermal effect related to the growth of Si precipitates increasing their volume fraction is observed at relatively high temperatures (350-460 deg. C) during linear heating. The formed precipitates are stable up to ?460 deg. C, where the modelled critical radius becomes bigger than most of the Si precipitates formed so far

  6. Precipitation kinetics of Si in aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lasagni, Fernando [Institute of Materials Science and Technology, Vienna University of Technology, Karlsplatz 13/E308, A-1040 Vienna (Austria)], E-mail: lasagni@pop.tuwien.ac.at; Mingler, Bernhard [Institute of Materials Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Dumont, Myriam [TECSEN-UMR 6122, Universite Paul Cezanne Aix-Marseille III, Faculte des Science et Techniques de St-Jerome, Case 261, 13397 Marseille Cedex 20 (France); Degischer, Hans Peter [Institute of Materials Science and Technology, Vienna University of Technology, Karlsplatz 13/E308, A-1040 Vienna (Austria)

    2008-05-15

    The precipitation kinetics of Si in an Al-1.7 wt.%Si alloy after different thermal treatments has been studied by means of transmission electron microscopy (TEM), dilatometry and differential scanning calorimetry (DSC). The results obtained are explained by a model based on simple nucleation and growth/dissolution laws and are compared with measured precipitate size distributions. The evolution of precipitates in water-quenched samples during linear heating depicts the exothermic formation of platelets and globular Si precipitates (200-300 deg. C). The endothermal dissolution of Si platelets starts at lower temperatures than that of the globular precipitates. Coarsening and finally dissolution of globular precipitates is observed with increasing temperature. Samples slowly cooled from the solution treatment temperature present mostly globular precipitates, which are nucleated during cooling. Here, an exothermal effect related to the growth of Si precipitates increasing their volume fraction is observed at relatively high temperatures (350-460 deg. C) during linear heating. The formed precipitates are stable up to {approx}460 deg. C, where the modelled critical radius becomes bigger than most of the Si precipitates formed so far.

  7. 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.

  8. Selective anodic dissolution and corrosion of copper-aluminium alloys in chloride-alkaline solution

    International Nuclear Information System (INIS)

    Anode behaviour and corrosion of Cu, Al-alloys in 0.4 M NaCl+0.6 M NaOH solution (pH = 12.4) as functions of aluminium content in copper-base homogeneous solution are studied by means of potentiodynamic polarization, chronopotentiometry and atom-absorption spectroscopy. It is revealed that kinetics of selective dissolving of alloys is determined by diffusion rate of aluminium atoms in the alloy surface layer with diffusion factor of 10-12 - 10-13 cm2/s . The rate of dealuminizing of the alloy surface increases proportionally to aluminium content

  9. 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.

  10. Rolling and annealing texture of 3004 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.F.; Jiang, X.P.; Hu, Z.C.; Wang, F.; Zuo, L. [School of Materials and Metallurgy, Northeastern Univ., Shenyang (China)

    2002-07-01

    The 3004 aluminium alloy used for beverage cans, require stringent material properties and earing behavior of the final sheet is of great importance. Final texture and thereby earing is controlled by deformation and heating processes in a most complicated manner where hot rolling, cold rolling and recrystallization are key issues. The hot rolling, cold rolling and annealing textures of the 3004 aluminium alloys were studied by means of orientation distribution functions (ODFs). The results show that texture in the hot-rolled plate is (100)[uvw] and the rotated cube orientation {l_brace}100{r_brace} left angle 011 right angle is the strongest. The intensity of the rotated cube orientation {l_brace}100{r_brace} left angle 011 right angle increases with the increase of the reduction The cold rolling textures show a typical copper-type feature and the intensity of deformation texture increases with the increase reduction The final cold rolling textures are composed of S-, Cu- and Bs-components. After isothermal annealing for 2 h, the recrystallization textures are different from the deformation ones. The recrystallization textures are mainly composed of Cube-, annealing R/S and copper components. The desired cube texture is the strongest at 400 C. The evolution of texture during recrystallization is described in detail and possible origins of various components are discussed. (orig.)

  11. Contradictory effect of chromate inhibitor on corrosive wear of aluminium alloy

    International Nuclear Information System (INIS)

    Research highlights: ? Corrosive wear of aluminium alloy in inhibited artificial acid rain was studied. ? Tribometer with linear reciprocating ball-on-flat geometry was used.? Corrosion potential, polarization current and friction coefficient were measured. ? Chromate decreases corrosion of aluminium alloy under wear conditions. ? Chromate in general accelerates corrosive wear of the alloy in acid rain. - Abstract: The corrosive wear of D16T aluminium alloy in artificial acid rain was studied. A special tribometer with the linear reciprocating ball-on-flat geometry was used. The setup allows to measure simultaneously an open circuit potential, to carry out potentiostatic and potentiodynamic polarization studies of the alloy corrosion and to record the friction coefficient. It was established that the addition of strontium chromate inhibitor to the working environment decreases an electrochemical corrosion of the aluminium alloy under wear conditions, but in general accelerates its destruction due to insufficient wear resistance of a formed surface film.

  12. Low temperature oxidation of niobium alloy with silicon-aluminium coating

    International Nuclear Information System (INIS)

    Using the gravimetry methods heat resistance of niobium-titanium-aluminium alloy in the air and at 700 deg C in the initial state and when it is protected by silicide-aluminium coatings (with variable content of aluminium) is investigated. Using X-ray diffraction and micro X-ray diffraction analyses, mechanisms of the alloy oxidation and the coating protective effect are studied. The role of aluminium in the formation of coatings is analyzed and according to bend tests the plasticity of the coatings is evaluated

  13. Ultrasonic Welding of Aluminium to Titanium: Microstructure, Properties, and Alloying Effects

    OpenAIRE

    Zhang, Chaoqun

    2015-01-01

    Use of welded titanium alloy to aluminium alloy structures in the aerospace industry has a number of potential benefits for both cost and weight saving by enabling titanium to be used only in the most critical parts, with the cheaper and lighter aluminum alloy making up the rest of the structure. However, due to the formation of brittle intermetallic compounds (IMC) at interface and the enormous gap in melting point, the welding of titanium to aluminium remains a major challenge. Solid state ...

  14. A study of the anodic behaviour of aluminium alloys in alkaline electrolytes

    OpenAIRE

    Walters, B.N.

    1988-01-01

    Recent studies an the discharge performance of aluminium alloys in alkaline media have led to improved alloys with significantly lower corrosion rates and more anodic potentials. Performance, of various alkaline electrolytes have also been examined and considerable progress has been made in this area. A review of the available literature reveals a list of several elements which are suitable for alloying with aluminium as regards reducing corrosion and overpotential. Previous work at the Chemi...

  15. Fracture toughness behaviour of FSW joints aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Strombeck, A. v.; Santos, J.F. dos; Torster, F.; Laureano, P.; Kocak, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2000-07-01

    The friction stir welding (FSW) process can be successfully used to achieve defect-free joints in Al-alloys. However, a thorough characterisation of the joints is needed in order to satisfy the stringent requirements of advanced applications such as aerospace, automotive and shipbuilding. In this work, FSW was performed on four different aluminium alloys, namely 5005-H14, 2024-T351, 6061-T6, and 7020-T6 (plate thickness being 5 mm except alloy 5005 which is 3 mm thick). The main objective was to establish the local microstructure-property relationships and to determine the fracture toughness levels of welded plates with weld zone strength undermatching. The FSW welds were void and crack free in all of the investigated alloys. Tensile and fracture toughness properties (in terms of CTOD) of the FSW joints were determined at room temperature in addition to extensive hardness measurements and tensile tests. The effects of strength mismatch and local microstructure on the fracture toughness of these joints were discussed. (orig.)

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

    Science.gov (United States)

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

    2015-12-01

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

  17. Microstructure and mechanical properties of thixoformed A319 aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: • A319 was successfully thixoformed at 50% liquid, i.e. at 571 °C. • T6 heat treatment has increased the strength and hardness of the thixoformed alloy. • The elongation after T6 heat treatment is even significantly improved. • The iron-rich intermetallic phase reduces the strength of the thixoformed alloy. - Abstract: Thixoforming is a viable technology for forming alloys in a semisolid state into near net-shaped products. In the present study, the effect of a thixoforming process on the microstructure and mechanical properties of A319 aluminium alloy was investigated. The ingots obtained from the cooling slope were thixoformed in a press after they remained at 571 °C for 5 min, yielding a microstructure predominantly composed of ?-Al globules and inter-globular Si particles. Some of the thixoformed samples were treated with an ageing process (T6) and then, hardness and tensile samples were prepared from the as-cast, as-thixoformed and thixoformed T6. All the thixoformed samples were characterised using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) as well as hardness measurements and tensile tests. The results indicate that the mechanical properties of the thixoformed A319 alloy increased after the T6 heat treatment (hardness of 124.2 ± 3.2 HV, tensile strength of 298 ± 3.0 MPa, yield strength of 201 ± 2.6 MPa and elongation to fracture of 4.5 ± 0.3%). The fracture samples from the tensile test were analysed, revealing that the iron-rich intermetallic observed in the samples reduced the tensile strength and ductility of the thixoformed A319 alloys

  18. PROCESS CAPABILITY STUDY OF A RAPID CASTING SOLUTION FOR ALUMINIUM ALLOYS USING THREE-DIMENSIONAL PRINTING

    Directory of Open Access Journals (Sweden)

    R. Singh

    2011-12-01

    Full Text Available In the present work, the best shell wall thickness of a mould cavity was investigated in a process capability study of a rapid casting solution for aluminium alloys using three-dimensional printing (3DP. Starting from the identification of a component/benchmark, an aluminium-alloy casting prototype was produced with different shell wall thicknesses by three dimensional printing. The results of the study suggest that, at the best shell wall thickness (5 mm for aluminium alloys, the rapid casting solution using a 3DP process lies within the ±3.999 sigma (? limit.

  19. TECHNOLOGICAL PRINCIPLES OF THE HETEROGENEOUS ALUMINIUM ALLOYS PRODUCTION AT PARTIAL DISSOLUTION OF FAST-COOLED DISPERSE ALLOY

    Directory of Open Access Journals (Sweden)

    L. P. Dolgij

    2015-11-01

    Full Text Available The article is dedicated to the matters of improvement of special characteristics such as hightemperature strength, corrosion resistance, thermalphysic indices of alloys on the basis of aluminium by means of alloying them by elements of transition group. Influence of concentrations of elements in addition alloy, speed of its cooling, methods of introduction, portions of alloys introduction, content of applied fluxes and other factors on the structure and characteristics at production of heterogeneous aluminium alloys with the purpose of ensuring of high exploitation characteristics of castings is examined.

  20. Quantitative prediction of solute strengthening in aluminium alloys.

    Science.gov (United States)

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

    2010-09-01

    Despite significant advances in computational materials science, a quantitative, parameter-free prediction of the mechanical properties of alloys has been difficult to achieve from first principles. Here, we present a new analytic theory that, with input from first-principles calculations, is able to predict the strengthening of aluminium by substitutional solute atoms. Solute-dislocation interaction energies in and around the dislocation core are first calculated using density functional theory and a flexible-boundary-condition method. An analytic model for the strength, or stress to move a dislocation, owing to the random field of solutes, is then presented. The theory, which has no adjustable parameters and is extendable to other metallic alloys, predicts both the energy barriers to dislocation motion and the zero-temperature flow stress, allowing for predictions of finite-temperature flow stresses. Quantitative comparisons with experimental flow stresses at temperature T=78 K are made for Al-X alloys (X=Mg, Si, Cu, Cr) and good agreement is obtained. PMID:20676087

  1. High effective organic corrosion inhibitors for 2024 aluminium alloy

    International Nuclear Information System (INIS)

    The inhibiting effect of several organic compounds on the corrosion of 2024 aluminium alloy in neutral chloride solution was investigated in the present work. The candidates were selected based on the assumption that effective inhibitors should form highly insoluble complexes with components of AA2024. Along with organic complexing agents, the salts of rare-earth elements were included into screening electrochemical impedance spectroscopy (EIS) test for getting comparative data. Results of EIS analysis revealed three most effective organic inhibitors: salicylaldoxime, 8-hydroxyquinoline and quinaldic acid. Their anti-corrosion performance was additionally investigated via dc polarization, as well as localized techniques: scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy coupled with scanning Kelvin probe (SKPFM). Localized measurements at exactly the same microdimensional zones of the alloy before and after immersion into 0.05 M sodium chloride solution allowed tracing the evolution of the Volta potential, chemical composition, surface topography and formation of corrosion products on the surface and intermetallic inclusions during the corrosion tests. The results show that the quinaldic acid, salicylaldoxime and 8-hydroxyquinoline provide anti-corrosion protection for AA2024 forming a thin organic layer of insoluble complexes on the surface of the alloy. Inhibiting action is the consequence of suppression of dissolution of Mg, Al and Cu from the corrosion active intermetallic zones

  2. Alloy development and associated dimensional changes of aluminium alloys during liquid phase sintering

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.M.; Castro, F. [Centro de Estudios e Investigaciones Tecnicas de Guipuzcoa (CEIT) and TECNUN, San Sebastian (Spain)

    2003-07-01

    The sintering behaviour and microstructural evolution of two aluminium alloys, of the 2XXX and 7XXX series, has been studied under, both, laboratory and industrial conditions. Quenching experiments from selected temperatures during the heating cycles, coupled with microstructural characterisation by Electron Microscopy, were used to investigate the gradual approach towards equilibrium of the alloys, from the as-pressed powder mixtures to the consolidated state after sintering. Differential Scanning Calorimetry was used to identify the reactions leading to the formation of liquid phases during sintering while the associated dimensional changes were determined by Dilatometry. The sinterability of these alloys and the development of necks between the solid aluminium particles is based upon the initial formation of transient liquid phases that favour the incorporation of alloying additions, followed by the development of permanent liquid phases, mainly containing Zn/Mg/Al and Cu/Al for the 7XXX and 2XXX series, respectively, leading to the densification of the alloys. A series of geometrically complex components with adequate dimensional tolerance and properties were industrially produced for an automotive application using the 2XXX series P/M Al alloy. (orig.)

  3. Characterization of oxyde films and conversion layers on aluminium alloys

    International Nuclear Information System (INIS)

    Corrosion resistance and specific functional properties (dielectrical and decorative properties, adhesion, wear resistance) of aluminium alloys can be improved by surface treatments as electrochemical or chemical conversion reaction. The purpose of this study is to discuss the applicability of spectroscopic ellipsometry (SE) and electrochemical impedance spectrometry (EIS) for the characterization of the obtained conversion surface layers. It can be concluded that SE yields an accurate characterization for the thickness and the interfacial properties of both the barrier an porous oxide layer. The EIS allows to measure and to determine the sealing grade of the porous layer. These two complementary techniques can be used to investigate the growth mechanism of phosphate chromate conversion layers. (orig.)

  4. 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.

  5. THE PHYSICAL METALLURGY OF ALUMINIUM-LITHIUM-COPPER-MAGNESIUM-ZIRCONIUM ALLOYS-8090 AND 8091

    OpenAIRE

    Miller, W.; White, J.; Lloyd, D

    1987-01-01

    Aluminium alloys containing up to 3wt% lithium and cast using an ingot metallurgy route are currently being developed for aerospace applications. The objective of this paper is to review the current status of the metallurgical understanding of these alloys. Particular emphasis is placed on the alloy system Al-Li-Cu-Mg-Zr, which includes the alloys 8090 and 8090 developed in the United Kingdom by the Royal Aircraft Establishment and Alcan. Comparison is made with other alloy systems, where app...

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

    DEFF Research Database (Denmark)

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

    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...

  7. 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

  8. 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

  9. Sol-gel derived nanocomposite materials for corrosion protection of aluminium alloys

    OpenAIRE

    Schmidt, Helmut K.; Müller, Peter; Dittfurth, Carola; Albayrak, Sener; Puhl, Anne

    2000-01-01

    Thermally curable nanocomposite coating materials have been developed to seal and protect copper-containing aluminium alloys against corrosion. The coating material was prepared via the sol-gel-process starting from epoxy functionalised silanes, nanoscaled silica and organic diole crosslinker. This coating matrix was additionally supplied with a varying content of cerium oxide (1-20 wt.%). The corrosion protective efficiency of these coatings was investigated on aluminium alloys Al 6013-T6 an...

  10. 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.

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

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan; Davenport, A.J.; Delabouglise, D; Petit, J.-P.; Neel, O.

    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 ...

  12. Corrosion of aluminium-zinc-rare earth alloys in solutions of polyvanadic acid salts

    International Nuclear Information System (INIS)

    Electrochemical behaviour of aluminium alloys with rare earth metals (Sc, Y, Nd, Ce, P) in polyvanadium acid salt solutions has been studied by the method of anodic polarization curves. It has been ascertained that in the salt series NaVO3-KVO3-NH4VO3 their depolarizing activity as regards the aluminium-zinc alloys studied, decreases due to increase in vanadate-anions polymerization degree. 10 refs.; 2 figs

  13. Characterization and Modelling of the Anisotropic Behaviour of High-Strength Aluminium Alloy

    OpenAIRE

    Fourmeau, Marion

    2014-01-01

    The purpose of the present study is to describe and characterize the anisotropic flow and fracture behaviour of a high-strength aluminium alloy. To this end,  thick plates of AA7075-T651 aluminium alloy have been tested. Different specimen geometries were used to investigate various stress states. Each specimen was machined in different directions of the plate to enlighten the anisotropy of the material. For all tests, the plastic flow exhibited a slight anisotropy while the failure strain an...

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

    OpenAIRE

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

    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.

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

    OpenAIRE

    Mojisola O. Nkiko; Janet T. Bamgbose

    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...

  16. The adsorption of an epoxy acrylate resin on aluminium alloy conversion coatings

    OpenAIRE

    Grilli, R; Abel, ML; Baker, MA; Dunn, B; Watts, JF

    2011-01-01

    A thermodynamic study of the adsorption of an epoxy acrylate resin used for UV-cured coatings on two different anticorrosion pretreatments on aluminium alloys relevant to aerospace industry has been undertaken. Aluminium alloy Al2219 specimens, treated with an inorganic chromate based conversion coating (Alodine 1200S) and an organic titanium based conversion coating (Nabutan STI/310), were immersed in solutions of different concentrations of the resin and adsorption isotherms were determined...

  17. Surface mechanical behaviour of composite Ni-P-fly ash/zincate coated aluminium alloy

    International Nuclear Information System (INIS)

    Ni-P-fly ash coatings were produced on zincate coated 5083 wrought aluminium alloy substrates with the aid of an electroless deposition technique. Structural and chemical characterization of the produced coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-P-fly ash coating was found to consist of an amorphous Ni-P matrix with dispersed fly ash particles. The wear resistance of the Ni-P-fly ash coating on zincate treated aluminium alloy was observed to be higher than that of the bare aluminium alloy, when sliding against a stainless steel counterface. In addition, the adhesion between the Ni-P-fly ash/zincate coating and the aluminium alloy substrate was also studied with a scratch testing apparatus. The adhesion strength of Ni-P-fly ash/zincate coating on the aluminium alloy substrate was observed to be higher in comparison to the Ni-P/zincate coating on the same aluminium alloy.

  18. 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)

  19. Incorporation of transition metal ions and oxygen generation during anodizing of aluminium alloys

    International Nuclear Information System (INIS)

    Enrichment of nickel at the alloy/film interface and incorporation of nickel species into the anodic film have been examined for a sputtering-deposited Al-1.2at.%Ni alloy in order to assist understanding of oxygen generation in barrier anodic alumina films. Anodizing of the alloy proceeds in two stages similarly to other dilute aluminium alloys, for example Al-Cr and Al-Cu alloys, where the Gibbs free energies per equivalent for formation of alloying element oxide exceeds the value for alumina. In the first stage, a nickel-free alumina film is formed, with nickel enriching in an alloy layer, 2 nm thick, immediately beneath the anodic oxide film. In the second stage, nickel atoms are oxidized together with aluminium, with oxygen generation forming gas bubbles within the anodic oxide film. This stage commences after accumulation of about 5.4 x 1015 nickel atoms cm-2 in the enriched alloy layer. Oxygen generation also occurs when a thin layer of the alloy, containing about 2.0 x 1019 nickel atoms m-2, on electropolished aluminium, is completely anodized, contrasting with thin Al-Cr and Al-Cu alloy layers on electropolished aluminium, for which oxygen generation is essentially absent. A mechanism of oxygen generation, based on electron impurity levels of amorphous alumina and local oxide compositions, is discussed in order to explain the observations

  20. 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

  1. 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, ...

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

    OpenAIRE

    Abdel-Nasser .M. Omran

    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...

  3. 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)

  4. Severe wear of a near eutectic aluminium-silicon alloy

    International Nuclear Information System (INIS)

    The severe wear of a near eutectic aluminium-silicon alloy is explored using a range of electron microscopic, spectroscopic and diffraction techniques to identify the residually strained and unstrained regions, microcracks and oxidized regions in the subsurface. In severe wear the contact pressure exceeds the elastic shakedown limit. Under this condition the primary and eutectic silicon particles fragment drastically. The fragments are transported by the matrix as it undergoes incremental straining with each cyclic contact at the asperity level. The grains are refined from ?2000 nm in the bulk to 30 nm in the near surface region. A large reduction in the interparticle distance compared with that for a milder stage of wear gives rise to high strain gradients which contribute to an enhancement of the dislocation density. The resulting regions of very high strain in the boundaries of the recrystallized grains as well as within the subgrains lead to the formation of microvoids/cracks. This is accompanied by the formation of brittle oxides at these subsurface interfaces due to enhanced diffusion of oxygen. We believe that the abundance of such microcracks in the near surface region, primed by severe plastic deformation, is what distinguishes a severe wear regime from mild wear.

  5. Ductility of aluminium alloy AA7075 at high strain rates

    Energy Technology Data Exchange (ETDEWEB)

    El-Magd, E.; Brodmann, M. [Technische Hochschule Aachen (Germany). Dept. of Mater. Sci.

    2000-09-01

    Under dynamic loading the stabilising effect of increased strain rate sensitivity of the material restrains neck formation in tension tests and leads to an increase in ductility. On the other hand the adiabatic character of the deformation process reduces the flow stress and promotes instability, localisation and adiabatic shear band initiation. Furthermore, the notch sensitivity of the material increases with increasing strain rate. Dynamic and quasi-static tension and compression tests were carried out on the age hardenable aluminium wrought alloy AA7075. There, dispers distributed precipitations are often the starting point for ductile fracture caused by impact due to the nucleation, growth and coalescence of voids and micro-cracks in case of tension. Neck formation under tensile loading and instabilities like shear bands in case of compression are discussed on the basis of the theory of imperfection under consideration of the increased strain rate sensitivity of the material and the adiabatic character of the deformation process at high strain rates. In case of tensile loading, tests with various notched geometries allowed the study of the influence of degree of multiaxiality. Through combination of experiment and simulation, the influence of strain rate on the local fracture strain could be determined for tensile and compression loading. (orig.)

  6. Residual stress measurements in laser clad aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Fatigue and corrosion damage of structural components threatens the safety and availability of civil and military aircrafts. There is no sign of relief from these threats as civil and military aircrafts worldwide are continuously being pushed further into and past their initial design fatigue lives in tight financial circumstances. Given fatigue and corrosion damage often initiates at the surface and sub-surface of the components, there has been extensive research and development worldwide focused on advanced aircraft repair technologies and surface enhancement methods. The Deep Surface Rolling (DSR) is one of advanced surface enhancement technologies that can introduce deep compressive residual stresses into the surface of aircraft metallic structure to extend its fatigue life. For the development of cost-effective aircraft structural repair technologies such as laser cladding, in this study, aluminium alloy 7075-T651 specimens with simulated corrosion damage were repaired using laser cladding technology. The surface of the laser cladding region was then processed by DSR. The experimental results from subsequent fatigue testing of laser cladded baseline, DSR and post-heat treated laser cladded specimens discovered that the DSR process can significantly increase fatigue life in comparison with the ascladded baseline. The three dimensional residual stresses were measured by neutron diffraction and the results confirmed the beneficial compressive residual stresses at the cladding surface can be achieved in depth more than 1.0 mm.

  7. Nanostructure of aluminium alloy 2024: Segregation, clustering and precipitation processes

    International Nuclear Information System (INIS)

    Variations in solute element distribution occurring in a commercial 2024 aluminium alloy during isothermal ageing treatments at 170 deg. C for up to 120 h have been characterized using atom probe tomography. An early (0.5 h at 170 deg. C) rapid increase in hardness was correlated with the formation of fine scale (average 24 atom) solute clusters, comprising principally Mg and Cu, but with minor concentrations of Si and Zn. There was, in addition, evidence of significant segregation of Mg, Cu and Si to at least some fraction of grain boundaries and existing matrix dislocations. At peak hardness (80 h at 170 deg. C) the microstructure comprised coarse precipitates of S phase, with a composition approaching stoichiometric Al2CuMg, a dense distribution of Guinier-Preston-Bagaryatsky zones elongated parallel to in a matrix of α-Al and a residual distribution of smaller equiaxed solute clusters. Both the clusters and zones contained predominantly Mg and Cu, with minor concentrations of Si and Zn. The S phase contained small but significant (0.5-1.8 at.%) concentrations of Si, which was non-uniformly distributed in elongated domains within the laths of the S phase. In overaged samples (114 h at 170 deg. C) the microstructure comprised almost exclusively coarse S phase, Al2Mg(Cu,Si), in assemblies suggestive of a combination of precipitate coarsening and coalescence.

  8. 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 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

  9. Mushy Zone Properties and Castability of Aluminium Foundry Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, A.K.

    1996-01-01

    The growing application and market share of aluminium castings demand better understanding of the mechanisms of defect formation during casting. Although casting is a cost-effective production route, inadequate reproducibility and quality of the cast structure often restrict the utilization of castings. This doctoral thesis aims to (1) determine how the solidification conditions affect the rheological behaviour in the partially solidified state, (2) to measure how alterations in solidification variables influence castability, and (3) to investigate the relationship between mushy zone rheology and castability. The development of mechanical strength in the mushy zone was measured as a function of chemical composition. Measurements of the dendrite coherency point provided accurate determination of the point where the dendrite network is established. The strength measurements confirm that the dendrites are largely independent and free-floating before dendrite coherency. The point and rate of strength development in the subsequently established interdendritic network strongly depend on the size and morphology of the dendrites and fraction solid. The castability investigation was limited to evaluations of fluidity and feeding. Fluidity measurements showed a complex effect of increased grain refinement. Alterations of the concentration and type of main alloying element gave a direct relationship between mushy zone rheology and fluidity. The range of the operating feeding mechanisms during solidification is directly related to the rheological properties of the mushy zone. 251 refs., 77 refs., 25 tabs.

  10. Excimer laser treatment for aluminium alloy mechanical property enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Sicard, E.; Boulmer-Leborgne, C. [Orleans Univ. (France). GREMI; Andreazza-Vignolle, C.; Andreazza, P. [CRMD, Universite d`Orleans, BP 6752, 45067, Orleans, cedex2 (France); Langlade, C.; Vannes, B. [IFOS, Ecole centrale de Lyon, 36 avenue de collongue, BP 163, 69131, Ecully, cedex (France)

    1998-03-01

    An excimer laser beam is focused (1-3 Jcm{sup 2}) on to an aluminium alloy (AlSi7Mg) surface target in a nitrogen atmosphere (760 Torr). A nitride layer (5 mm{sup 2} area per laser spot) is obtained by nitrogen diffusion in the bulk with a depth of several micrometres during the induced laser-plasma time interaction on the surface. For chemical, structural and tribological analyses, 1 x 1 cm{sup 2} samples are processed by scanning the laser beam on the surface, either by locating the laser-plasma spots side by side or by overlapping them. Different experimental conditions are investigated (laser fluence, laser pulse number, overlapping rate of laser-plasma spots), and then various analysis such as NRA, XRD, GIXD, SEM, EDS are performed. When a step-by-step process is used, the nitrogen concentration appears to be inhomogeneous depending on the surface location, and the surface roughness is too high for further applications. Nevertheless, the overlapping process yields homogeneous chemical composition layers with smooth surfaces. Tests are performed to characterise the friction behaviour of the treated surface under fretting conditions, and tribological results clearly indicate the best experimental conditions to be used for the enhancement of mechanical properties. (orig.) 16 refs.

  11. Radiation effects in the aluminium alloys irradiated with neutrons

    International Nuclear Information System (INIS)

    Full text: Materials of fuel elements for water cooled nuclear reactors are exposed to simultaneous action of an ionizing radiation, temperature and yields of water radiolysis. In particular, irradiation by fast neutrons (En> 0.1 MeV) in research reactors influences mainly the mechanical properties of aluminium alloys, increasing their strength and reducing the plasticity. Radiation can essentially affect the stability of the heat-generating assembly material, changing its structure state. The structure change may also be the result of post-radiation ageing. This paper presents the results of studying the influence of reactor neutrons (research reactor of INP AS RU) on microstructure, electrical characteristics and length changes of SAV-1 and AMG-2 aluminium alloys used in nuclear industry. These alloys are low-alloyed solid solutions and intermetallic phases of CuAl2, Mg2Si, CuMgAl2, CuMg4Al6, Al2Mg2 in an equilibrium state. Samples were cut with orientation in 111 crystallographic axis in the shape of disks with the diameter d= 15 mm and thickness h= 3 mm for the metallographic analysis, and rods with the length of 40 mm and width d = 5 mm for measuring specific electrical resistance and linear dimension changes prior and after irradiations. For precise measurements the sample surfaces were mechanically handled and polished in a chemical solution, and then washed out in the distilled water and ethanol. Further samples, were put into the aluminum container and irradiated in a vertical channel of the reactor to fluencies 1018, 1019, 1020 n/cm2. The relative elongation (extension) ? was calculated as the measured length ratio of the non-irradiated and irradiated sample: ?=L0/L1x100%. Determination of element composition and the metallographic analysis of studied samples were done at the X-ray microanalyzer 'Jeol' JSM 5910 IV. Specific resistance (?) values were measures with four probe technique by compensation method at the direct voltage. The sample lengths were measured by means of a micrometer. Under the irradiation the sample surface is oxidized, and local nonsoluble intermetallic phases of Al-Mg-Si-Fe system are shattered and diffused in the sample volume practically uniformly. Such smashing of local nonsoluble intermetallic phases, finally, leads to essential local change of the element composition, increase of phase interfaces, magnification of interior mechanical stresses, and, hence, to increase in deficiency. The considerable increase of the structure deficiency level of the irradiated alloy is shown first of all in the observed ? increase. For the SAV-1 sample the ? value increases from 3.53x10-6 Ohm·m for not irradiated reference up to 3.86x10-6 Ohm·m after the fluency increase to 1020 cm-2 and for alloy AMG-2 from 3.60x10-6 Ohm·m to 5.31x10-6 Ohm·m, respectively. The neutron irradiation induced change of ? depends on the impurity contents. For the SAV-1 sample the relative extension is incremented at the beginning to 0.52 % at 1018 cm-2, then decreases proportionally to a neutron fluence to 0.47 % at 1020 cm-2. For the AMG-2 alloy sample the fluence dependence of ? was found more complicate. At 1.3x1018 cm2 the length reduction was at first 0.23 %, then increases smoothly to 0.25 % at 1.5x1019 cm-2 and decreased to 0.1 % at 1.2x1020 cm2. The irradiation induced defects of crystal lattice entered have created the energy barrier system in the materials, and charge carriers scattered at the barriers that resulted in the ? magnification. The dislocation density increases in metal with smashing of intermetallic phases. However, their motion is interfered by major number of demarcations. As a result the explored alloys become a little strengthened while losing plasticity. Hardening is promoted also by other irregularities of the crystalline structure, such as atoms of the impurities dissolved in metal and alloying elements, inclusions of the secondary phases, boundaries of grains or blocks etc, and also by braking dislocation motion. Regarding the observed small values of ?, it is possible to conclude

  12. Investigation into structure and properties of the piston aluminium alloy processed by electron beam

    International Nuclear Information System (INIS)

    Mechanical properties of the piston aluminium alloys after hardening electron-beam processing are studied. Considerable structural alloy components dispersion caused by the hardness and wear-resistance increasing accordingly at 1.5-1.6 and 2-2.6 times compared to the initial state is determined

  13. 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)

  14. Influence of modification on structure, fluidity and strength of 226D aluminium alloy

    Directory of Open Access Journals (Sweden)

    A. Dolata-Grosz

    2008-08-01

    Full Text Available In the article the fluidity, solidification conditions, microstructure and tensile properties have been studied for the non-modified and modified 226D aluminium silicon alloy.Realized investigations concerned modification of alloy 226D for application as the matrix to carbon fibre reinforcement composite (MMC-Cf. One of main factors determining to good connection between metal matrix and fibres reinforcement is good wettability. It is possible to obtain suitable conditions of wettability by modification of chemical composition metal matrix alloy or proper sizing of reinforcement fibres. Into consideration of interaction between liquide aluminium and carbon fibers following modifiers were used for addition to the commercial aluminium alloy (226D. The magnesium (2%Mg, strontium (0,03%Sr and titanium (0,5%Ti with boron (0,01%B modifiers and their combination were used in the presented work.

  15. Investigation of interphase hydrogen distribution in aluminium alloys by autoradiographical analysis method

    International Nuclear Information System (INIS)

    The distribution of hydrogen in the structure of binary alloys of aluminium with silicon, titanium and zirconium has been studied. Specimens were activated by tritium in a special installation. It was shown of the intermetallic compounds formed by aluminium with hydride forming elements (Al3Ti, Al3Zr), the solubility of hydrogen is greater than in the solution of aluminium. A study of the microstructure and the autoradiogram of the Al-Zr alloy, in which the large intermetallic compound carries cracks, has established that hydrogen can be adsorbed on the surface of cracks and other micro-discontinuities inside the metal. A study of the autoradiogram of alloys subsequent to heat treatment has shown that the latter can affect substantially the character of distribution of hydrogen. The segregation of hydrogen on the inter-phase boundaries of intermetallic compounds can have a substantial effect upon the behaviour of alloy in plastic deformation and failure

  16. Investigation of aluminium-rich alloy system of aluminium-strontium-silicium

    International Nuclear Information System (INIS)

    An area of the solid solution based on aluminium was studied, and the surface was plotted of the liquidus adjoining the apex of the aluminium corner of the strontium-aluminium-silicon system. The investigation was carried out by microstructure and differential thermal analyses and by the measurement of the microhardness of the component phases. A combined solubility of silicon and strontium in aluminium was studied along three radial sections at Sr-to-Si ratios of 1/2, 1/1 and 2/1. The relationships of ''composition vs. Microhardness'', obtained in these sections, made it possible to define the boundaries of the phase regions in the aluminium corner of the strontium-aluminium-silicon system at 500 deg C. The greatest solubility is that along the Al-SrAl2Si2 section at a Sr/Si ratio of 1/2. A further increase in the content of strontium brings about a drop in the solubility of silicon in solid aluminium. The projection of the liquidus surface of the strontium-aluminium-silicon system, rich in aluminium, includes four surfaces of primary crystallization: ?-Al, SrAl4, SrAl2Si2 and Si. The system comprises a section of Al-SrAl2Si2 representing a quasibinary system of an eutectic type. The eutectic reaction takes place at a temperature of 640 deg C. The quasibinary Al-SrAl2Si2 section divides the aluminium corner of the Sr-Al-Si system into two independent systems Al-SrAl4-SrAl2Si2 and Al-Si-SrAl2Si2 of an eutectic type

  17. Corrosion Behaviour of Alpha Phase Aluminium Bronze Alloy in Selected Environments

    Directory of Open Access Journals (Sweden)

    Oluwayomi BALOGUN

    2014-02-01

    Full Text Available This research investigated the corrosion behaviour of aluminium (8 wt % bronze alloys produced via sand casting in acidic, alkaline, and marine environments. The aluminium bronze was produced from aluminium (6063 alloy and copper scraps by sand casting according to European standard specification (UNS. C61400-CuAl8, after which they were cut into smaller sizes and immersed in the selected corrosive media for corrosion test investigation. H2SO4, NaCl, NaOH, and HCl of 0.1 M, 0.2 M, 0.3 M, 0.4 M, and 0.5 M were setup for 45 days for the corrosion study. Selective phase attack was observed in the alloy, although it was much more pronounced in HCl, to the point where entire grains fell out while it exhibit minimal corrosion resistance in marine and alkaline media respectively. Intense chloride attack on the protective film formed on the surface of the aluminium bronze was observed to be responsible for the greater corrosion susceptibility of the alloy in HCl environments. Comparative studies of aluminium bronze in selected environments indicated that no corrosion was observed and the alloys have a greater tendency to be applicable in marine, alkaline and sulphuric acid environments.

  18. 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)

  19. 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...

  20. 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)

  1. Investigation of selective atomization and radiation-induced segregation of impurities in aluminium alloyed with scandium

    International Nuclear Information System (INIS)

    The methods of RBS and Auger-electron spectroscopy were applied to investigate selective atomization and radiation-induced segregation of impurities in AMG type aluminium alloys irradiated by 10 keV H+ ions. Introduction of 0.5% scandium into the alloy suppresses magnesium radiation-induced segregation to surface, that results in sharp decrease of its content in the composition of atomized particles, and the total coefficient of alloy atomization decreases approximately 2 times

  2. 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...

  3. Water chemistry during storage of the research reactor spent fuel assemblies, fabricated from aluminium base alloys

    International Nuclear Information System (INIS)

    The results of the experiment on the storage and examination of the aluminium samples of the research reactor spent fuel elements are described. The experiments were carried out in the MIR reactor spent fuel storage pool. The effect of the pool water-chemical mode (WCM) on the aluminium alloys corrosion is analyzed. The experimental results made it possible to determine the WCM optimal parameters for the reactor spent fuel storages

  4. Application of heat-removing aluminium coatings in welding zirconium alloys with 2.5% Nb

    International Nuclear Information System (INIS)

    Effect of heat-removing aluminium coatings of 1...2.7 mm thickness on thermal arc welding cycles of 2.5% niobium zirconium alloy of 7 and 2 mm thickness was considered. It is shown that use of such coatings permits to reduce heat affected zone width 2-3 times as well as to decrease metal stay time at temperatures above 1270 K owing to high thermal conductivity of aluminium and ideal thermal contact of cooled surface with coating

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

    OpenAIRE

    S. Solay Anand; Mohan, B.; 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...

  6. 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.

  7. Tribological Behaviour of W-DLC against an Aluminium Alloy Subjected to Lubricated Sliding

    OpenAIRE

    S Bhowmick; Banerji, A.; A.T. Alpas

    2015-01-01

    Diamond like carbon (DLC) coatings mitigate aluminium adhesion and reduce friction under the ambient conditions but their tribological behaviour under lubricated sliding need to be further investigated. In this study, tribological tests were performed to evaluate the friction and wear characteristics of W-DLC and H-DLC coatings sliding against an aluminium alloy (319 Al) under unlubricated (40 % RH) and lubricated sliding conditions. For unlubricated sliding, coefficient of friction (COF) val...

  8. 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 ...

  9. Synthesis and study of binary compounds of actinides and lanthanides. 21. On curium alloy formation with aluminium

    International Nuclear Information System (INIS)

    Microsamples of curium-244 alloys with aluminium, prepared by high-temperature condensation of one component vapors on a thin metallic film of the other component, have been studied. New data on the regularities of curium-aluminium alloy formation and influence of 244Cm intensive alpha-decay on crystal structure of the solid compounds formed have been obtained. 8 refs., 5 tabs

  10. 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...

  11. Electrochemical aspects of exfoliation corrosion of aluminium alloys: The effects of heat treatment

    International Nuclear Information System (INIS)

    Research highlights: ? Development of new aluminium alloys for aircraft industries. ? Impact of chemical composition change during tempering on exfoliation corrosion. ? Role of hydrogen in the exfoliation corrosion of aluminium-based alloys. ? Mechanical effects and hydrogen bubbling during exfoliation corrosion. - Abstract: Electrochemical approaches are used to investigate the exfoliation corrosion (EFC) of a 7XXX series aluminium alloy that has undergone different tempering treatments. EFC was produced under an artificial crevice at open circuit potential in neutral chloride solutions, and is found to be associated to current and potential transients. EFC was also produced under galvanostatic control conditions. Observations made through Scanning Electron Microscopy (SEM) suggest that these transients result from the progression of inter-granular cracks. Last, over-ageing heat treatments that are known to decrease both metal hardness and EFC sensitivity were found to decrease the number of transients.

  12. 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.

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

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan; Davenport, A.J.; Delabouglise, D; Petit, J.-P.; Neel, O.

    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...

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

    Science.gov (United States)

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

    2015-08-01

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

  15. 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

  16. 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.

  17. Electrochemical Study of 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 Electrochemical corrosion studies of industrial Aluminium alloy AA 5083 corrosion in natural gas containing mercury metal and water as impurities showed to be a complex process. Single scan voltamograms of amalgamated electrode presents peaks of electrochemical oxidation around E = -1.4 volt/SCE and a corrosion potential Ecor = -1.6 volt/SCE showing an active amalgamated surface. Oxydation peak, Ip relating rate of electrochemical oxidation of aluminium was depending on three factors: thickness of amalgam and diffusivity of aluminium in amalgam, rate of chemical dissolution of aluminium in mercury which is the limiting step at high scanning rate potential and low immersion time. Diffusional step which controls kinetics at highest immersion time and lowest scanning rate and an intermediate step which controlled by the two kinetics.

  18. MICROSTRUCTURAL AND MECHANICAL STUDY OF ALUMINIUM ALLOYS SUBMITTED TO DISTINCT SOAKING TIMES DURING SOLUTION HEAT TREATMENT

    Directory of Open Access Journals (Sweden)

    Valmir Martins Monteiro

    2014-12-01

    Full Text Available This work studies the microstructural characteristics and mechanical properties for different aluminium alloys (1100, 3104 and 8011 hot rolled sheets that were subjected to a solution heat treatment with distinct soaking times, in order to promote microstructural and mechanical changes on these alloys with solute fractions slightly above the maximum solubility limit. Scanning Electronic Microscopy (SEM / Energy Dispersive Spectroscopy X-Ray (EDS, X-Ray Diffraction (XRD and Hardness Tests were employed to observe the microstructural / compositional and mechanical evaluation. For the 1100 and 8011 alloys the more suitable soaking time occur between 1 and 2 hours, and for the 3104 alloy occurs between 2 and 3 hours.

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

    OpenAIRE

    A. Zyska; Konopka, Z.; M. ??giewka; M. Nadolski

    2011-01-01

    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...

  20. 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)

  1. Temperature dependence of radiation blistering in aluminium alloys under helium ion bombardment

    International Nuclear Information System (INIS)

    Invstigations into the radiation-induced blistering of AMg type aluminium alloys have been performed. The 40 and 80 keV helium ions were employed for irradiation of samples in the temperature range of 50 to 600 deg C with the incident ion beam normal to the target or at an angle. The coefficients of the alloy sputtering by 10 keV H+ ions have been measured. The effect of radiation-induced segregation of the magnesium atoms in the AMg alloy has been revealed. The AMg alloy with Sc-addition could be recommended as a possible material for the INTOR first wall

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

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl

    2015-01-01

    Surface treatment of aluminium alloys using steam with oxidative chemistries, namely KMnO4 and HNO3 resulted in accelerated growth of oxide on aluminium alloys. Detailed investigation of the corrosion performance of the treated surfaces was carried out using potentiodynamic polarisation and standard industrial test methods such as acetic acid salt spray (AASS) and filiform corrosion on commercial AA6060 alloy. Barrier properties of the film including adhesion were evaluated using tape test under wet and dry conditions. Electrochemical results showed reduced cathodic and anodic activity, while the protection provided by steam treatment with HNO3was a function of the concentration of NO3?ions. The coating generated by inclusion of KMnO4showed highest resistance to filiform corrosion. Overall, the performance of the steam treated surfaces under filiform corrosion and AASS test was a result of the local coverage of the alloy microstructure resulting from steam containing with KMnO4and HNO3.

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

    Science.gov (United States)

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

    2015-11-01

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

  4. 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)

  5. Corrosion monitoring of aluminium alloys in the TRIGA IPR-R1 research reactor

    International Nuclear Information System (INIS)

    Aluminium alloys and stainless steels have been used as cladding materials for nuclear fuel in research reactors, such as the TRIGA IPR-R1 reactor, located at the Centre for Development of Nuclear Energy in Belo Horizonte, Brazil. In order to develop a fundamental understanding of the corrosion problems with aluminium- and stainless steel-clad in the TRIGA IPR-R1 reactor, a monitoring programme has been initiated, as part of an IAEA sponsored Regional Technical Cooperation Project for Latin America (RLA/4/018). The programme consists of in-pool tests using corrosion surveillance coupons made of aluminium alloys and stainless steel. This paper presents the surveillance programme developed for the TRIGA IPR-R1 reactor and the analysis of the first corrosion rack removed from reactor in July 2003, after 1 year of exposure. (author)

  6. A beryllium window for electron beam injection and extraction in an aluminium alloy uhv system, TRISTAN

    International Nuclear Information System (INIS)

    The window for electron beam injection and extraction in the accumulation ring of TRISTAN consists of an aluminium alloy frame and a vacuum tight beryllium foil. A beryllium foil is used because of low loss in electron beam energy, mechanical strength necessary to isolate vacuum and atmosphere, high thermal conductivity and low residual radioactivity. When an electron beam welding method is used to make a joint between a beryllium foil and an aluminium alloy there can be problems with the reliability during the heat cycling. A simplified electron beam welding method is described to make a beryllium window. Results of helium leak tests on the beryllium window during thermal cycling using an aluminium Helicoflex seal are given. (U.K.)

  7. 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

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

    DEFF Research Database (Denmark)

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

    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...

  9. 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.

  10. 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.

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

    OpenAIRE

    Puga, Hélder; Barbosa, J; Costa, Sónia; 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...

  12. 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...

  13. 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...

  14. Development of tools for integrated optimisation and use of aluminium alloys

    OpenAIRE

    Zander, Johan

    2011-01-01

    Commercial alloys are continuously developed to improve their performance. Therefore it is useful to establish new optimisation software, which could be used in development of new materials or in materials selection. In the first part of the thesis, mechanical and technological properties, which are of importance in materials selection in mechanical design, are investigated. Two types of materials are analysed for the mechanical properties, aluminium alloys and stainless steels but only alumi...

  15. Corrosion Control of Friction Stir Welded AA2024-T351 Aluminium Alloys

    OpenAIRE

    Younes, Yousif Younes Abo

    2010-01-01

    Friction stir welding (FSW) is a modern solid state welding technique developed at thewelding institute (TWI) in 1991. The joining is achieved by heat generation, materialsoftening and plastic deformation following the travelling of non-consumable pin throughthe gap between the two workpieces to be joined.In present study, joining of AA 2024-T3 aluminium alloy, is achieved by FSW. Theinfluence of the FSW on the alloy microstructure and corrosion behaviour is determined.The effect of laser sur...

  16. 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 investigatio...

  17. 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...

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

    OpenAIRE

    K. Mroczka; Dutkiewicz, J; L. Lity?ska-Dobrzy?ska; A. Pietras

    2008-01-01

    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 ...

  19. New rapidly solidified aluminium alloys for elevated temperature applications on aerospace structures

    OpenAIRE

    Barbaux, Y.; Pons, G.

    1993-01-01

    This paper presents the results of a cooperative study between AEROSPATIALE, DASSAULT AVIATION, BRITISH AEROSPACE, ALENIA, IMPERIAL COLLEGE, CEREM, ALPOCO, RAUFOSS A/S, CENIM AND THE UNIVERSITYOF PISA supported by the CEC under BRITE EURAM contract BREU 0356 C which aims at developping a new Aluminium alloy for use at 250 - 300°C by Rapid Solidification /Powder Metallurgy technology. Tensile and creep properties at temperatures up to 350°C, fracture toughness and corrosion results on 11 alloy...

  20. Aluminium Alloy AA6060 surface treatment with high temperature steam containing chemical additives

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Tabrizian, Naja; Jellesen, Morten S.; Ambat, Rajan

    The steam treatment process was employed to produce a conversion coating on aluminium alloy AA6060. The changes in microstructure and its effect on corrosion resistance properties were investigated. Various concentrations of KMnO4 containing Ce(NO3)3 was injected into the steam and its effect on...

  1. Coefficient of linear heat expansion of alloy's systems of aluminium-beryllium and rare metals

    International Nuclear Information System (INIS)

    The article considers about the results of experimental date coefficient of linear heat expansion of alloy's systems of aluminium-beryllium and rare earth metals (Al-Be-Rare Earth Metals) in dependence of temperature (temperature liquids nitrogen to the 637 K)

  2. Thermal-mechanical fatigue behaviour of the cast aluminium alloy AlSi7Mg

    Energy Technology Data Exchange (ETDEWEB)

    Luft, J.; Beck, T.; Loehe, D. [Univ. of Karlsruhe, Inst. fuer Werkstoffkunde I (Germany)

    2004-07-01

    The present report gives results of OP-TMF-tests and OP-TMF-tests (OP=out-of-phase) with superimposed mechanical high cycle fatigue (HCF) loading at the cast aluminium alloy AlSi7Mg0.3-T6. The results are interpreted on the basis of stress-strain curves, S-N-curves and metallographic examinations.

  3. 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

  4. Irradiation effects in surface layers of aluminium alloys and austenitic steels

    International Nuclear Information System (INIS)

    The regularities and features of physical processes (blistering, sputtering, radiation-induced segregation and radiation-intensified sublimation), occurring in surface-adjacent layers of aluminium alloys and austenitic steels under the action of the fluxes of accelerated charged ions and electrons are considered

  5. Approximation model of the stress-strain curve for deformation of aluminium alloys

    Directory of Open Access Journals (Sweden)

    J. Horsinka

    2011-04-01

    Full Text Available The main purpose of this paper is to give a mathematical description of flow stress of examined aluminium alloys on the basis of upsetting tests perdormed in a servohydraulic plastomer. Deformation curves have been described by means of the Sellars-Tegart-Garofalo equation, with the aid of linear regression analysis by the neural network method implemented in the NEUREX program.

  6. Cleaning of aluminium alloy chambers with ozonized water

    International Nuclear Information System (INIS)

    In the fabrication of aluminium vacuum chambers of the Taiwan Photon Source (TPS), a cleaning treatment with ozonized water followed machining in an ethanol environment. After cleaning with ozonized water, aluminium samples were analyzed according to Auger electron spectroscopy (AES) and measurement of the thermal outgassing rate and photon-stimulated desorption (PSD). The results showed that cleaning with ozonized water has a superior performance. A thermal outgassing rate q72 ? 6.4 x 10-12 Pa · m/s after baking and a photon-desorption yield ? ? 2 x 10-5 molecules/photon at an accumulated beam dose 3 x 1021 photons/cm2 were obtained

  7. 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.

  8. Recovery of tritium from lithium-sintered aluminium product (SAP) and lithium-aluminium alloys

    International Nuclear Information System (INIS)

    The tritium release rates of irradiated samples of lithium-containing aluminium (Li-Al) and sintered aluminium product (Li-SAP) were investigated to evaluate the potential application of both materials in fusion reactors. The observed release rates followed the pattern expected for bulk diffusion of tritium in a solid. Therefore, diffusion coefficients for tritium in Li-SAP were determined over a temperature range of 383 and 5000C and tritium in Li-Al at 4500C. At 4500C, the diffusion coefficients of tritium in Li-SAP and Li-Al are 2.988 x 10-10 cm2 sec-1 and 1.462 x 10-6 cm2 sec-1, respectively. (author)

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

    OpenAIRE

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

    2008-01-01

    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 pain...

  10. Elaboration in the area of aluminium containing alloys

    International Nuclear Information System (INIS)

    In the Institute of Chemistry was elaborated the experimental-industrial installation and technology of deep aluminium purification by the methods of zone melting and recrystallization. The developed technology let receive the metal of model A5 N A6 N dependence from number of induction zone passage

  11. Indium segregation in dilute indium-aluminium alloys

    International Nuclear Information System (INIS)

    Polycrystalline as well as single-crystal samples of aluminium containing 14-58 at. ppm indium were quenched from a temperature TQ=350-5500C to -900C and subsequently annealed during 15 min at step-wise increasing temperatures. After each step a PAC measurement was carried out. (orig./TW)

  12. 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.

  13. 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.

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Torres, E; Ugues, D [Politecnico di Torino DICHI, Corso Duca degli Abbruzzi 24, 10129 Torino (Italy); Brytan, Z [Politecnico di Torino, Sede di Alessandria, Viale T. Michel 5, 15100 Alessandria (Italy); Perucca, M [Clean NT Lab Division, Environment Park S.p.A. Via Livorno 58/60, Torino (Italy)], E-mail: eloy.torres@polito.it

    2009-05-21

    In this work, a nanocomposite (Cr,Al){sub x}N{sub 1-x}/Si{sub 3}N{sub 4} 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-Cr{sub 1-x}Al{sub x}N 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.

  16. 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.

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

    International Nuclear Information System (INIS)

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

  18. 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.

  19. 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.

  20. 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.

  1. The investigation on aluminium alloys automobile wheel with low-titanium content produced by electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Jingpei Xie [Key Lab. of Material physics, Ministry of Education, Zhengzhou Univ. (China); Coll. of Mater. Sci. and Eng. Henan Univ. of Science and Technology, Luoyang (China); Jiwen Li; Zhongxia Liu; Yonggang Weng; Tianfu Song; Zhiyong Liu; Jiefang Wang [Key Lab. of Material physics, Ministry of Education, Zhengzhou Univ. (China); Aiqin Wang [Coll. of Mater. Sci. and Eng. Henan Univ. of Science and Technology, Luoyang (China)

    2005-07-01

    The in-situ Ti alloying of aluminium alloys was fulfilled by electrolysis, and the material was made into A356 alloy and used in automobile wheels. The results show that the grains of the A356 alloy was refined and the second dendrites arm was shortened due to the in-situ Ti alloying. Trough 3-hour solution treatment and 2-hour aging treatment for the A356 alloy, the microstructures were homogeneous, and Si particles were spheroid and distribute in the matrix fully. The outstanding mechanical properties with tensile strength ({sigma}{sub b}{>=}300 Mpa) and elongation values ({delta}{>=}10%) have been obtained because the heat treatment was optimized. Compared with the traditional materials, tensile strength and elongation were increased by 7.6{proportional_to}14.1% and 7.4{proportional_to}44.3% respectively. The qualities of the automobile wheels were improved remarkably. (orig.)

  2. 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

  3. Precipitate assemblies formed on dislocation loops in aluminium-silver-copper alloys

    OpenAIRE

    Rosalie, Julian M; Bourgeois, Laure; Muddle, Barrington C.

    2012-01-01

    The precipitation microstructure of the \\gamma' (AlAg2) intermetallic phase has been examined in aluminium-silver-copper alloys. The microstructure developed in an Al-0.90at.%Ag-0.90at.%Cu alloy was significantly different from that reported for binary Al-Ag alloys. The orientation relationship between the matrix and precipitate was unchanged; however, the \\gamma' phase formed as aggregates with a two-dimensional open assemblies. Each such assembly contained two variants of the \\gamma' phase ...

  4. 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 ...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    The surface treatment of aluminium alloys under steam containing KMnO4 and HNO3resulted in the formation of an oxide layer having a thickness of up to 825 nm. The use of KMnO4 and HNO3 in the steam resulted in incorporation of the respective chemical species into the oxide layer. Steam treatment ...... particles resulting in poor coverage by the steam generated oxide layer compared to the coating formed using MnO4?ions. Further, increase in the concentration of NO3?ions in the solution retards precipitation of the steam generated aluminium hydroxide layer....

  6. Surface modification of aluminium alloys using hybrid treatment techniques

    International Nuclear Information System (INIS)

    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.

  7. ATOM-PROBE STUDY OF ALUMINIUM-LITHIUM ALLOYS

    OpenAIRE

    MENAND, A; Al Kassab, T.; Chambreland, S.; Sarrau, J.

    1988-01-01

    We analysed Al-Li based alloys by means of atom-probe. The influence of parameters such as the tip temperature and the pulse fraction on the apparent composition were investigated for an Al-2.7at%Li alloy and for an Al-7.5at%Li-1.2at%Cu alloy. A ternary Al-3.5wt%Li-3.6wt%Mg alloy aged 24h at 190° C was studied. Atom-probe results point out the presence of Mg in the ?' phase.

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

    Science.gov (United States)

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

    2015-11-01

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

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

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Piotrowska, Kamila

    2015-01-01

    The surface treatment of aluminium alloys under steam containing KMnO4 and HNO3resulted in the formation of an oxide layer having a thickness of up to 825 nm. The use of KMnO4 and HNO3 in the steam resulted in incorporation of the respective chemical species into the oxide layer. Steam treatment with solution containing HNO3 caused dissolution of Cu and Si from the intermetallic particles in the aluminium substrate. The growth rate of oxide layer was observed to be a function of MnO4?and NO3?ions present in the aqueous solution. The NO3?ions exhibit higher affinity towards the intermetallic particles resulting in poor coverage by the steam generated oxide layer compared to the coating formed using MnO4?ions. Further, increase in the concentration of NO3?ions in the solution retards precipitation of the steam generated aluminium hydroxide layer.

  10. 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.

  11. 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

  12. The relation between liquation and solidification cracks in pulsed laser welding of 2024 aluminium alloy

    International Nuclear Information System (INIS)

    It is a known fact that 2024 aluminium alloy is susceptible to solidification cracking in the weld metal and liquation cracking in the base metal when welded with fusion processes. The main purpose of this study is investigating whether these two types of cracks act independently or are related with each other in terms of initiation and propagation as this can lead to enhancing the understanding of the hot cracking phenomena in these alloys. Laser welding whether continuous or pulsed has promising outlooks for welding heat treatable aluminium alloys. But the fast heating and cooling rates involved in pulsed laser welding give rise to unique successively repeating microstructural features which provides an interesting base for studying the cracks. Thus, the experimentation involved Nd:YAG pulsed laser welding of 2024 aluminium alloy. The observations indicate that liquation cracks in the partially melted zone of wrought base metal have strong association with solidification cracks in the weld metal and accordingly it is proposed that the liquation cracks act as a strong initiation sites for solidification cracks. It is also shown that healing of liquated grain boundaries through backfilling can have a significant role on resistance to liquation cracking in the partially melted zone and that in turn can affect tendency for solidification cracking in the weld metal.

  13. Soudage homogène MIG de l'alliage d'aluminium 6061 MIG homogeneous welding of 6061 aluminium alloy

    Directory of Open Access Journals (Sweden)

    Benoit Alexandre

    2013-11-01

    Full Text Available Le soudage homogène (métal d'apport identique au métal de base de l'alliage d'aluminium 6061 avec un procédé dit semi-automatique (MIG n'a jamais été reporté jusqu'à maintenant dans la littérature. Nous montrons ici que l'utilisation d'un dérivé du procédé de soudage MIG, le MIG CMT (Cold Metal Transfer permet d'obtenir des cordons de soudures sains (sans fissuration à chaud. De plus des traitements thermiques ont permis de retrouver partiellement ou de restaurer totalement les propriétés de la soudure. Nos résultats sont comparés à des essais de soudage MIG CMT avec le métal d'apport préconisé pour le soudage de l'alliage 6061. The homogeneous welding (same filler metal as base metal of the 6061 aluminium alloy with MIG process has never been reported in the open access literature. This work shows that the CMT (Cold Metal Transfer MIG, a derivative of MIG, allows producing welds without hot-cracking. Moreover, further heat treatments partially increased or fully restore the mechanical properties of the weld. These results are compared with 6061 heterogeneous welds usually met in the industry.

  14. Investigation of Kelvin probe force microscopy efficiency for the detection of hydrogen ingress by cathodic charging in an aluminium alloy

    OpenAIRE

    Larignon, Céline; Alexis, Joël; Andrieu, Eric; Lacroix, Loïc; Odemer, Grégory; Blanc, Christine

    2013-01-01

    Detecting and locating absorbed hydrogen in aluminium alloys is necessary for evaluating the contribution of hydrogen embrittlement to the degradation of the mechanical properties for corroded or cathodically hydrogen-charged samples. The capability of Kelvin probe force microscopy (KFM) to overcome this issue was demonstrated. Aluminium alloy samples were hydrogenated by cathodic polarisation in molten salts (KHSO4/NaHSO4.H2O). The presence of absorbed hydrogen was revealed; the affected zon...

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

    OpenAIRE

    Nagel, A.; M. Kremzer; L.A. Dobrza?ski,

    2007-01-01

    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 po...

  16. Microstructure and mechanical properties of melt-spun aluminium alloys consolidated by spark plasma sintering and forging

    OpenAIRE

    Schubert, Thomas; Lorenz, Bernd; Steger, Jürgen; Weißgärber, Thomas; Neugebauer, Reimund; Kieback, Bernd

    2012-01-01

    Spark Plasma Sintering (SPS) is a promising sintering technology to produce nearly fully dense bulk pre-compacts from micro- or nano-structured aluminium alloys at lower temperatures and shorter sintering times. The densification behaviour and sintering response of melt-spun aluminium alloys sintered using SPS was studied depending on the processing parameters. The measured bending strength of the only SPSed material shows relatively low values due to the insufficient metallic bonding within ...

  17. ALUMINIUM-LITHIUM-COPPER-MAGNESIUM-ZIRCONIUM ALLOYS WITH HIGH STRENGTH AND HIGH TOUGHNESS - SOLVING THE PERCEIVED DICHOTOMY

    OpenAIRE

    Miller, W.; White, J.; Reynolds, M.; Mcdarmaid, D.; Starr, G.

    1987-01-01

    Throughout the past decade extensive research and development has been carried out on aluminium-lithium base alloys because of the attractive combination of lower density and higher modulus that can be achieved in this system compared with "conventional" aluminium alloys. Much of this effort has been directed at understanding and overcoming their "Achilles heel" of low ductility and poor fracture toughness (particularly for crack planes perpendicular to the short transverse direction). This s...

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

    OpenAIRE

    Girisha.K.B1 ,; Dr.H.C. Chittappa2

    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...

  19. 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

  20. Mechanical properties of submicrocrystalline aluminium alloys after severe plastic deformation using equal channel angular extrusion

    International Nuclear Information System (INIS)

    Influence of severe plastic deformation by means of equal-channel and complex angular extrusion and of submicrocrystalline (SMC) structure on static tensile strength at room temperature of basic compositions of thermally nonstrengthened and strengthened industrially deformed aluminium alloys (Al-Mg, Al-Mg-Li-Zr) was analyzed. It is shown that a unique combination of their strength and ductility can be achieved by complex treatment including severe plastic deformation and conventional methods of thermal and strain effects in thermally nonstrengthened and low-alloy thermally strengthened alloys. The conclusion is made that imparting SMC structure by means of severe plastic deformation by angular extrusion to most complex-alloyed industrial thermally strengthened alloys to improve their static strength is not effective

  1. 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.

  2. New process produces superplastic aerospace/automotive aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Troeger, L.P.; Starke, E.A. Jr. [Virginia Univ., Charlottesville, VA (United States). Dept. of Materials Science and Engineering

    2000-12-01

    A new thermomechanical process has been developed which renders an Al-Mg-Si-Cu alloy superplastic, making this material a candidate for superplastic forming (SPF). Industrial capabilities were taken into account during process development. The alloy investigated falls within the composition ranges of both aluminum alloys 6013 and 6111. The refined microstructure has an average grain diameter of approximately 10 mm and an average grain aspect ratio near 1.6 and exhibits superplasticity above 500 C. The uniaxial elongation reached 375%. (orig.)

  3. First results on nitriding aluminium alloys in a low-pressure RF plasma

    International Nuclear Information System (INIS)

    Full text: Aluminium alloys are now well established as materials of choice for many commercial applications, especially where strength-to-weight ratio is a critical parameter. However, their more widespread use is inhibited by their low surface hardness. For steels, similar problems can be overcome by nitriding. The nitrogen-rich surface layer has high hardness and load-bearing capacity, and is very well bonded to the substrate. The development of a similar surface-treatment process for aluminium alloys is clearly a desirable goal. It is therefore not surprising that many research groups worldwide have attempted to nitride aluminium. Much of this work studied pure aluminium, a material of no interest for structural applications. Previous investigations into nitriding aluminium alloys' had indifferent results. However, they have served to identify the key issues, which are the importance of a pre-cleaning steps to remove the surface oxide, of impurity control during the nitriding and the desirability of using as low a process temperature as possible. In all of these areas, our process using a low-pressure RF plasma is likely to be competitive. In view of this, we have undertaken a comparative study of a range of commercially available aluminium alloys. All treatments were carried out in the hot-wall nitriding reactor at ANSTO. The samples consist of disks 25mm in diameter and ∼3mm thick which were polished and ultrasonically cleaned in alcohol prior to treatment. The samples were stored in air at all times except when in the nitriding reactor. In a series of treatments, the treatment time was varied in the range 1-16 h and the temperature in the range 350-500 deg C. All treatments were preceeded by a plasma cleaning step in a H2/50%Ar mixture for a duration of 1.5-2.0 h while the reactor reached processing temperature. The treatments all used pure N2 at a pressure of 0.4Pa and a nitrogen flow rate of 12μmol s-1, with 245W of rf power at 13.56MHz applied to the antenna and a workpiece bias of -250V with respect to the reactor walls. All alloys displayed various surface colorations following treatment. This work was supported by the Australian Institute of Nuclear Science and Engineering, the Australian Research Council, and an Australian Postgraduate Research Award

  4. Corrosion of aluminium alloys in research reactor cores - processes and assessment

    International Nuclear Information System (INIS)

    Around 250 research reactors (RR) are presently operating and these consist of several types, use fuels of different designs and have varying power levels and core configurations. The commonly used RR core materials include aluminium alloys, stainless steels and zirconium alloys. Aluminium alloys are used for cladding fuels and absorbers, targets, thermal columns and other irradiation facilities. Regardless of reactor type or application, most RR cores are surrounded by water that functions as a coolant, moderator and biological shielding. In this metal/environment system, aluminium alloys are prone to different types of corrosion, namely uniform, pitting, crevice and galvanic corrosion. Parameters that affect these forms of corrosion are water chemistry, temperature, solids in suspension, flow rate, bimetallic contacts and crevices. Much information is available about Al corrosion and is used in the design stage of core components. Nevertheless, many factors cause these 'well designed components' to corrode and these include transients in specific water parameters, synergism in the effects of certain water parameters, planned but inappropriate design changes, lack of or inappropriate surveillance practices and other site-specific constraints. The corrosion resistance of Al alloys can be seriously impaired in the presence of very small quantities of chloride ions in the primary coolant water and by contact with other materials. Oxide growth on Al alloy surfaces depends on surface state, temperature and water parameters such as pH, conductivity, dissolved species, flow rate and heat flux. Aluminium alloys, like other metals that rely on surface oxide films for protection are particularly susceptible to pitting and crevice corrosion. Galvanic corrosion is driven by differences in electrochemical potential, ratio of surface areas of the metals in contact and the distance between the metals in contact. This paper will present: (a) a brief overview of the different forms of corrosion of Al alloys and the effect of specific chemical and physical parameters on corrosion; (b) details of the on-going and previous corrosion surveillance programs in the IEA-R1 reactor at IPEN; (c) guidelines to plan and execute a corrosion surveillance programme to monitor and assess corrosion degradation of Al alloy core components in RR; (d) use of on-line and off-line measurements of specific parameters as well as visual inspection techniques to monitor the status of core components; (e) two case studies to highlight interpretation of data from on-line measurements, video imaging, off-line measurements (SEM/EDS/XRD) and a corrosion surveillance programme to explain fuel cladding degradation in the IEA-R1 research reactor at IPEN in Brazil. (author)

  5. RESEARCH OF FATIGUE AND MECHANICAL PROPERTIES AlMg1SiCu ALUMINIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Mária Mihaliková

    2015-11-01

    Full Text Available The paper is concerned with an analysis of utility and fatigue properties of industrially produced aluminium alloy, specifically EN AW 6061 (AlMg1SiCu, reinforced with the particles of SiC. The following properties were subject to evaluation: microstructure and sub-structure, mechanical characteristics. All of these mechanical properties in pre- and post- equal channel angular pressed (ECAP state have been studied. The hardness was evaluated by Vickers hardness test at the load of HV10. The significant part the thesis was devoted to the fatigue properties at cyclic load in torsion. The presented results demonstrate well that the combination of fractography and microscopy can give a significant contribution to the knowledge of initiation and propagation crack in the aluminium alloy.

  6. Monte Carlo calculations for the simulation of channeling experiments on irradiated aluminium alloys

    International Nuclear Information System (INIS)

    One of the most useful application of the channeling technique is the location of solute atoms in irradiation produced mixed dumbbells of aluminium alloys. Therefore here the channeling process is simulated on the basis of Monte Carlo calculations regarding the collisions of the channeled He ions with the nearest target atom in momentum approximation. Flux distributions are determined as a function of the angle of incidence. The report contains 81 figures each of which represents , , and axial as well as {100}, {110}, and {111} planar angular yields of He ions backscattered from solute atoms in mixed dumbbells of different concentrations. The solute atom is assumed to be displaced from the lattice site in , , or direction. On the basis of these curves the positions of the Mn, Ag, Cu, Ge, and Zn atoms in mixed dumbbells of aluminium alloys could be determined from experimental scans. (orig.)

  7. 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.

  8. 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.

  9. Mechanical properties of an undercooled aluminium alloy Al-0.6Mg-0.7Si

    International Nuclear Information System (INIS)

    Compression tests of an undercooled aluminium alloy Al-0.6Mg-0.7Si have been performed in a quenching and deformation dilatometer. Samples have been solution annealed and quenched in the dilatometer with varying quenching rates (0.1 K/min to 1000 K/min) and varying quenching temperatures. Immediately after quenching, compression tests on quenching temperature have been performed in the dilatometer. The results have been correlated with the precipitation behaviour of the undercooled aluminium alloy Al-0.6Mg-0.7Si. Stress-strain-curves of quenching rates higher than the critical cooling rate for precipitation differ from those of quenching rates lower than the critical cooling rate. Further, stress-strain-curves of temperatures above and during precipitation differ from those of temperatures below precipitation.

  10. 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 (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.

  11. 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.

  12. High-Rate Compaction of Aluminium Alloy Foams

    International Nuclear Information System (INIS)

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

  13. Foundry performance in relation to the radiographic quality of aluminium alloy sand castings

    International Nuclear Information System (INIS)

    This article examines radiographic soundness and acceptance standards for aluminium alloy sand castings for aerospace and general engineering applications. A method is suggested by which foundries can evaluate their performance to provide evidence of capability with respect to radiographic quality; purchasers could use the same system to assess suppliers. The shortcomings of standards are briefly discussed in the light of an approach to radiographic acceptance on the horizon

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

    OpenAIRE

    M. Pal Pandi; Dr. R. Kannan

    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...

  15. 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

  16. 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.

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

    OpenAIRE

    Ajit Kumar Senapati; Purna Chandra Mishra; Bharat Chandra Routara

    2014-01-01

    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 hardn...

  18. Laser surface treatments for adhesion improvement of aluminium alloys structural joints

    Energy Technology Data Exchange (ETDEWEB)

    Spadaro, Chiara [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)]. E-mail: c.spadaro@dicpm.unipa.it; Sunseri, Carmelo [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Centro Interdipartimentale di Ricerca sui Materiali Compositi, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Dispenza, Clelia [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Centro Interdipartimentale di Ricerca sui Materiali Compositi, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2007-08-15

    Laser technology is proposed as a friendly alternative treatment to chemicals involved in conventional prebonding adherend treatments. Aluminium alloy 2024 substrates were laser treated with different beam diameters and energy densities, and bonded using a structural epoxy adhesive. The influence of irradiation conditions on adherends morphology and adhesive joints' fracture energy was investigated. On the basis of different morphologies observed, an explanation of the effect of the surface treatment upon joint mechanical behaviour is attempted.

  19. Passivating oxide film and growing characteristics of anodic coatings on aluminium alloys

    OpenAIRE

    Feliu Jr., S.; Bartolomé, Mª. Jesús; González Fernández, José Antonio; López Serrano, Víctor; S. Feliu

    2008-01-01

    The paper studies some aspects of the behaviour of four aluminium alloys under chemical etching by sodium hydroxide solution and during their subsequent anodizing in sulphuric acid solution. A correspondence is seen between etching rate, thickness of the passivating oxide film and porosity of the anodic layer. The possibility of an influence on these properties of precipitates and micro-heterogeneities in the metallic surface is suggested

  20. Passivating oxide film and growing characteristics of anodic coatings on aluminium alloys

    Science.gov (United States)

    Feliu, S.; Bartolomé, M. a.. J.; González, J. A.; López, V.; Feliu, S.

    2008-02-01

    The paper studies some aspects of the behaviour of four aluminium alloys under chemical etching by sodium hydroxide solution and during their subsequent anodizing in sulphuric acid solution. A correspondence is seen between etching rate, thickness of the passivating oxide film and porosity of the anodic layer. The possibility of an influence on these properties of precipitates and micro-heterogeneities in the metallic surface is suggested.

  1. Modelling stress reduction techniques of cold compression and stretching in wrought aluminium alloy products

    OpenAIRE

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

    2003-01-01

    Heat treatable aluminium alloy aerospace products undergo a rapid quench from the solution heat treatment temperature into water/organic quenchant/spray quenching system during processing. As a result of this rapid quenching operation, residual stresses of yield strength magnitude can develop, leaving the material in an unsuitable condition for further machining operations and for service. Rectilinear, open-die forgings are generally cold compressed after quenching to relieve residual stresse...

  2. Structure and properties of ultrafine-grained aluminium alloys prepared by equal-channel angular pressing.

    Czech Academy of Sciences Publication Activity Database

    Dám, Karel; Jäger, Aleš; Vystav?l, Tomáš; Lej?ek, Pavel

    Aachen : RWTH Aachen University, 2010 - (Epple, D.; Nick , M.; Strämke, M.; Zilkens, C.), s. 141-144 ISBN N. [ISDM 2010. Aachen (DE), 16.09.2010-18.09.2010] R&D Projects: GA AV ?R KAN300100801 Institutional research plan: CEZ:AV0Z10100520 Keywords : Equal-Channel Angular Pressing * aluminium alloys * grain refinement Subject RIV: BM - Solid Matter Physics ; Magnetism

  3. Characteristics of aluminium-scandium alloy thin sheets obtained by physical vapour deposition

    International Nuclear Information System (INIS)

    Thin sheets of an age-hardenable aluminium-scandium alloy were deposited by direct current magnetron sputtering. As targets an aluminium-scandium pre-alloy with a scandium content of 2.0 mass% (size 88 x 500 mm) was applied. The substrates to be coated consisted of thin steel sheets which after deposition were dissolved in an oxidizing medium. In this way, free-standing sheets of less than 30 ?m thickness of the aluminium-scandium alloy were received. Two deposition temperatures, 37 and 160 oC, were applied. The as-received sheets showed a typical columnar structure. Two post-treatments of the sheets were applied: a cold isostatic pressing and an artificial ageing for 1 h at temperatures between 200 and 400 oC. The strength of the sheets was measured by tensile tests. The employed specimens had a width of 10 mm and were gained from the sheets by cutting. During testing, load and strain were measured by a 1000 N load cell and a video extensometer, respectively. The as-deposited specimens show a tensile strength of 350 MPa. Artificial ageing at 300 oC increases the tensile strength to more than 400 MPa. It could be shown that during tensile tests cracks are initialized at coating defects.

  4. Inhibitive Behaviour of Corrosion of Aluminium Alloy in NaCl by Mangrove Tannin

    International Nuclear Information System (INIS)

    Anticorrosion potential of mangrove tannins on aluminium alloys AA6061 in NaCl solution has been studied using potentiodynamic polarisation method and scanning electron microscopy (SEM). The study was carried out in different pH of corrosive medium in the absence and presence of various concentrations of tannin. The corrosion inhibition behaviour of the mangrove tannin on AA6061 aluminium alloy corrosion was found to be dependant on the pH of NaCl solution. Our results showed that the inhibition efficiency increased with increasing tannins concentration in chloride solution at pH 6. Treatment of aluminium alloy 6061 with all concentrations of mangrove tannins reduced the current density, thus decreased the corrosion rate. Tannins behaved as mixed inhibitors at pH 6 and reduction in current density predominantly affected in cathodic reaction. Meanwhile, at pH 12, addition of tannins shifted the corrosion potential to more cathodic potentials and a passivating effect was observed in anodic potentials. SEM studies have shown that the addition of tannins in chloride solution at pH 12 reduced the surface degradation and the formation of pits. (author)

  5. Kinetic and energetic oxidation of liquids ferro silicium alloyed by aluminium

    International Nuclear Information System (INIS)

    By authors was investigated the oxidation process of ferro silicium by thermogravimetric method which based on continuous weighing of sample at interaction of air oxygen. The alloy oxidation containing 45% of silicon was carried out at 1573 and 1623 K temperature. The oxidation curves shows that with the rising of temperature the oxidation velocity is rising. The influence of aluminium additions on the oxidation kinetics was investigated on examples of F S 45 alloys as among ferroalloys the F S 45 has most application

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

    Science.gov (United States)

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

    2013-09-01

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

  7. 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)

  8. Ageing and work-hardening behaviour of a commercial AA7108 aluminium alloy

    International Nuclear Information System (INIS)

    In the 7xxx aluminium alloying system several mechanisms influence the hardening behaviour of the alloys, e.g. particle size and distribution, dislocation density and alloying elements in solid solution. This work is an experimental study of ageing and work-hardening considering a commercial AA7108 alloy in the as-cast and homogenized condition. Tensile specimens have been exposed to a solution heat treatment and a two-step age-hardening treatment with varying time at the final temperature. The tensile data for the different tempers have been evaluated in elucidation of already existing models based on a one-parameter framework. The precipitate size and distribution have been further investigated in the transmission electron microscope for a selection of tempers, and the influence of these parameters on the work-hardening behaviour has been discussed.

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

    Directory of Open Access Journals (Sweden)

    Palomino Luis Enrique M.

    2003-01-01

    Full Text Available 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. EIS measurements on conversion-coated samples have shown that the presence of the layer increases the impedance, and that its presence is detected by the presence of a high frequency time constant. Results of potentiodynamic experiments have shown that the corrosion protection afforded by the conversion layer is due to the hindrance of the oxygen reduction reaction and that the pitting potential of the alloy is not changed.

  10. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

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

    2015-08-01

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

  13. 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

  14. 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)

  15. Corrosion studies on anodized aluminium alloys by electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Anodized clad aluminum alloy 2024 is characterized by electrochemical impedance spectroscopy (EIS). The effect of sealing, storage in dry air and mechanical defects on impedance spectra are investigated. Corrosion phenomena are monitored. It is possible, to distinguish between general and localized corrosion attack. Effects of various corrosion inhibitors on EIS spectra are determined as well

  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. Cavitation erosion resistance of microarc oxidation coating on aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng [School of Mechanical Engineering, Southeast University, Nanjing, 211189 (China); Jiang, Shuyun, E-mail: jiangshy@seu.edu.cn [School of Mechanical Engineering, Southeast University, Nanjing, 211189 (China); Liang, Jun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2013-09-01

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

  18. Study of thermodynamic properties of binary and ternary liquid alloys of aluminium with the elements iron, cobalt, nickel and oxygen

    International Nuclear Information System (INIS)

    The present work deals with the thermodynamic study of aluminium liquid alloys with the metals iron, cobalt and nickel. The experiments carried out lead to the activity, at 1600 deg C, of aluminium in the (Al, Fe), (Al, Co), (Al, Ni) liquid alloys. The experimental method used consists in studying the partition of aluminium between the liquid immiscible phases made up with the pairs of metals (Fe, Ag), (Co, Ag), (Ni, Ag). The informations so obtained are used for drawing the isothermal equilibrium phases diagrams sections of (Al, Fe, Ag), (Al, Co, Ag), (Al, Ni, Ag) systems. The study of the partition of silver between lead and aluminium joined with the determinations of several authors allows us to determine the aluminium activity, analytically presented, in the metal M (iron cobalt and nickel). The Wagner's interaction parameters of aluminium in metal M are determined. The results obtained as the equilibrium phases diagrams of (Al, M) systems allow to compare the thermodynamic properties of the Al Fe system in liquid and solid states and to estimate the enthalpies of melting of the AlCo and AlNi intermetallic compounds. The activity, at 1600 deg C, of aluminium in (Al, Fe, Co), (Al, Fe, Ni), (Al, Co, Ni) liquid alloys is estimated through thermodynamic properties of binary components systems by application of several methods leading to results in good agreement. The study of aluminium-oxygen interactions in the liquid metallic solvants M allows us to propose an explanation for the shape of the deoxidation equilibrium line of iron, cobalt and nickel by aluminium and to compare the de-oxidizing power of aluminium toward iron, cobalt and nickel oxides. (author)

  19. 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.

  20. Formation of zirconium-based conversion coatings on aluminium and Al–Cu alloys

    International Nuclear Information System (INIS)

    Highlights: ? Formation of zirconium-based conversion coatings is investigated on aluminium. ? Copper alloying is shown to reduce the rate of coating growth. ? Copper is shown to promote the formation of corrosion product beneath the coating. ? Compositions of coatings are determined using ion beam analyses. ? Oxidation rates of substrates are determined using sputtering-deposited layers. - Abstract: The influence of copper addition to aluminium on the formation of a zirconium-based conversion coating is investigated using sputtering-deposited substrates. Coatings formed on aluminium are ?1.5 times the thickness of the aluminium consumed by oxidation, with an O:Zr atomic ratio of ?2.5. Copper additions reduce the coating growth rate, especially when added in amounts above a few at.%. In contrast, the copper has relatively little effect on the oxidation rate of the substrate. Copper also promotes the formation of a layer of corrosion product beneath the coating and appears to influence the adherence of the coating to the substrate.

  1. Liquid metal corrosion on cladding materials, especially aluminium alloys, for target elements of a spallation neutron source

    International Nuclear Information System (INIS)

    Liquid metal corrosion and embrittlement have been investigated under conditions expected for the lead based target element of the spallation neutron source. Emphasis has been put on the reaction between liquid lead aluminium, as well as on the reaction of mercury, one of the spallation products, with the aluminium cladding of the target element. Tensile tests after a pretreatment in liquid mercury show for an AlCuMg alloy a severe decrease of the ductility. For a thin sheet specimen of the Al 6061-T6 alloy a dramatic loss of the ductility was found. Static isothermal corrosion tests show a severe attack of liquid lead on the aluminium alloys. In cyclic loading tests of AlMgSi-alloys in mercury a decrease in cycles to fracture was found at higher stress levels, but the fatigue limit was unaffected. (orig.)

  2. 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)

  3. 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.

  4. 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.

  5. 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

  6. Galvanic corrosion of aluminium-copper model alloys

    OpenAIRE

    Idrac, Jonathan; Mankowski, Georges; Thompson, George; Skeldon, Peter; Kihn, Yolande; Blanc, Christine

    2007-01-01

    Galvanic coupling between different ? and ? phase-containing model Al–Cu alloys, deposited by magnetron sputtering, has revealed that the anodic ? phase did not suffer corrosion and remained in the passive state in sulphate solution. Conversely, sulphate ions induced pitting of the cathodic ? phase. Pitting susceptibility of the cathode increased when the difference between the copper content of the anode and cathode increased. Similar observations were made for all the galvanic couples; furt...

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. Sputtering of aluminium alloys by bombardment with 0.5 keV neon ions

    International Nuclear Information System (INIS)

    Film cathode structures find ever growing application in gas discharge devices. One of the main requirements for them is high sputtering stability. The authors suggest ways of producing cathode structures stable to ion bombardment. It is well known that the process of disastrous destruction of aluminium alloys starts on after 400 hours of irradiation with 0.5 keV neon ions at 3*1016 cm-2s-1 particle flow density and 400 Pa pressure in a gas discharge device while at lower flow densities and higher pressures the above effect is not observed. To improve the sputtering stability of materials they were modified with lithium and beryllium. The resistance to sputtering is assumed to be enhanced due to specific structure of the aluminium-lithium and aluminium-beryllium compounds and the specified texture of the bombarded surface through the adjustment of the angular distribution of the sputtered atoms. Modification was carried out by sputtering Be-Al-Li and Be-Al-Cu alloys (Al as a base, Be under 5%, Li and Cu under 2%) on the substrate with an Al-layer followed by heat treatment and ion bombardment. Heat treatment was undertaken in vacuum with the aim to stabilize the structure at 670-720 K. Ion bombardment was carried out to clean the surface with 0.5-1 keV neon ions prior to irradiation with 1 keV oxygen ions for producing an oxide film

  13. 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.

  14. 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 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

  15. 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.

  16. 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)

  17. 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.

  18. Mechanical metallurgy of aluminium alloys for the beverage can

    Energy Technology Data Exchange (ETDEWEB)

    Courbon, J. [Aluminium Pechiney, 38 - Voreppe (France). Centre de Recherches

    2000-07-01

    3104 and 5182 are established packaging alloys with millions of beverage cans and ends produced everyday worldwide. Yet their continuous downgauging requires marginal improvements. They rely on a framework of experienced tests and models : metallurgy simulator, finite element structural or forming analysis.. Advances incorporate contributions from many sciences, of which many examples are given in this review: new material models and criteria (prediction of ears), original statistical methods (assessment of tear-off rate at pilot scale), new tests in close connection with finite element modelling for their interpretation (trousers tearing test). (orig.)

  19. 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)

  20. Accumulation of radiation defects in aluminium-tin alloy under low-temperature electron irradiation

    International Nuclear Information System (INIS)

    Interaction of interstitial atoms (ISA) and impurity tin atoms in aluminium was studied by measuring residual electric resistivity by the method of inverse accumulation rate of radiation defects at irradiation temperatures from 54 K to 158 K. The aluminium-21 at. ppmSn alloy was irradiated in the linear electron accelerator at 5.5 MeV energy. It is shown that tin atoms are effective ISA traps. The relative capture radius for ISA by tin atoms is 0.6±0.1 at 54 K. In the spectrum 2 of the annealing stage there is one peak at 150 K caused by dissociation of ISA-Sn atom complexes. The binding energy of such complexes is about 0.34 eV. At irradiation temperatures higher than 85 K, when dissociation of these complexes has begeen, a sharp decrease of the capture parameters is observed. 9 refs.; 2 figs

  1. 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.

  2. 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.

  3. Contribution to the study of helium precipitation in an aluminium-lithium alloy

    International Nuclear Information System (INIS)

    In order to determine the swelling mechanisms we have studied the behaviour of helium in aluminium using transmission electron microscopy. The helium was introduced into the aluminium by irradiation of Al-Li6 alloys containing small amounts of lithium. The influence of various factors on the nucleation and the swelling of the bubbles has been studied, they are: - the helium concentration - the temperature - the number and the distribution of crystal defects in the metal. We have shown furthermore that the precipitation of rare-gas bubbles could in certain cases prevent the recrystallization of the metal as a result of a mechanism depending on the anchoring of the dislocations and grain boundaries by the bubbles. (authors)

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

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2015-04-01

    Full Text Available 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°.

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

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Soyama, Juliano; Dirscherl, Kai; Canulescu, Stela; Schou, Jørgen; Ambat, Rajan

    2011-01-01

    . 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...

  6. 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°.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z., E-mail: zuojia.liu@gmail.com; Curioni, M.; Jamshidi, P.; Walker, A.; Prengnell, P.; Thompson, G.E.; Skeldon, P.

    2014-09-30

    Highlights: • Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation in NaCl electrolyte. • The exposed carbon fibres on the side and front regions are responsible for a high cathodic current density. • The NaCl + CuSO{sub 4} electrolyte was used to investigate the cathodic polarization behaviour of the exposed carbon fibres. • Galvanic coupling behaviour between the composite and aluminium alloys (AA7075-T6 and AA1050) was measured in NaCl electrolyte. • The higher galvanic current density measured on AA1050 alloy introduced a higher dissolution rate than the AA7075-T6 alloy. - Abstract: The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO{sub 4} 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.

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

    International Nuclear Information System (INIS)

    Highlights: • Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation in NaCl electrolyte. • The exposed carbon fibres on the side and front regions are responsible for a high cathodic current density. • The NaCl + CuSO4 electrolyte was used to investigate the cathodic polarization behaviour of the exposed carbon fibres. • Galvanic coupling behaviour between the composite and aluminium alloys (AA7075-T6 and AA1050) was measured in NaCl electrolyte. • The higher galvanic current density measured on AA1050 alloy introduced a higher dissolution rate than the AA7075-T6 alloy. - Abstract: 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

  10. Thermal capacity of A5 N aluminium and its alloys with silicon, copper and rare - earth metals

    International Nuclear Information System (INIS)

    Present article is devoted to thermal capacity of A5 N aluminium and its alloys with silicon, copper and rare - earth metals. The experimental studies of specific heat and heat - transfer coefficient of A5 N aluminum and its alloys with silicon, copper and rare-earth metals was conducted. It is revealed that process cooling of aluminum and its alloys has relaxational character. (author)

  11. 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...

  12. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Sudhakar

    2015-03-01

    Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  13. Corrosion Characteristics and Kinetics of Zircaloys and Aluminium Alloys

    International Nuclear Information System (INIS)

    Corrosion rate characterization of cladding materials has been done by dynamic method. The materials are zircaloy-2,zircaloy-4,AIMg2,and AIMgSi.The zircaloy alloys are characterized in the electrolytes of boric ion,iodide ion,lithium ion and cesium ion with a pH variation.The aluminum alloys are characterized in the cooling water of RSG-GAS reactor in different temperatures and Ph values .The results, show that corrosion product of iodine on zircaloy is not passivated, meanwhile the corrosion product of cesium undergoes passivation. However, the deposited substance in the surface of the specimens as indicated using WDX-SEM shows the same deposition rate.it is concluded therefore that iodine is diffused into the materials without getting resistance from the deposited substances on the surface. The effect of pH to corrosion rate of iodine on the zircaloy fluctuates meanwhile the cesium has the minimum corrosion rate at pH 7.5 At the concentration of 0.1 gram/1,cesium ion is more reactive than iodine but at higher concentration the reactivity becomes competitive . Furthermore , the interaction between zircaloy and boric ion at concentration of 300 ppm and lithium ion at 10 ppm shows an outstanding corrosion rate, i.e. 0.1 mpy. if both substances are mixed then the corrosion rate decreases drastically in the order of 10-2 mpy.The reason of such a decrease may be due to the formation of complexes of boron lithium on the electrode surface. The arrhenius activation energies for such reaction have been found to be 37629.322 joule/mole 0K for Al Mg2 and 41609.822 joule /mole 0K for AIMgSi ,respectively. This underlies the argument that AI Mg2 is more reactive than AI Mg Si besides , AI Mg2 is more reactive under acid condition meanwhile AI Mg Si more reactive under basic condition. Both alloys over come the minimum corrosion rate at the pH in between 4.7 to 7.5 and the level of the corrosion rate in the pH interval was outstanding

  14. Analytic and experimental study for light alloy aluminium panels under compression

    Directory of Open Access Journals (Sweden)

    A. Fayza

    2007-11-01

    Full Text Available Purpose: Aluminium alloys have been indispensable for the progress of many technologies during the last decades. In particular, most stiffeners in aerospace structures are composed of aluminium panels often solicited with elastic and plastic bucking under particular boundary and loading conditions. The purpose of this paper is to enhance the difficulties encountered to predict the incipient elastic-plastic buckling for thin aluminium plates under combined compressive loads.Design/methodology/approach: The used methodology was an analytic non linear approach, validated further with an experimental investigation. In fact, the instability of thin elastic-plastic rectangular panels made of 2024 T45 alloys is analyzed. General concept of the Von Kaman’s equation with a set of trigonometric and harmonic functions was used in the analytic model. The computation of buckling loads concerns both elastic and plastic instability solutions. Developments in the plastic range were concerned with the (j2d deformation and the (J2f flow constitutive laws.Findings: A methodology to develop this kind of analytic resolution is pointed out and has been illustrated for a set of variables. Several 2d and 3d plots, which can be used to predict incipient buckling strengths for plates with flat initial configurations, have been presented for the various load conditions.Research limitations/implications: In the future it will be possible to apply the investigated analytic procedure to other particular cases.Practical implications: Plots obtained with analytic solution can be used to predict incipient buckling strengths for plates with flat initial configurations are presented for the various tests. The interest of three dimensional representations is to indicate when plastic buckling occurs for a square plate under biaxial loading.Originality/value: This paper presents a stable and low cost analytic solution to deal with instability phenomenon in elastic and plastic range for the design of light alloy aluminium plates. This approach is applied to assess the conditions for which plastic buckling can happen when particularly thin aluminium panels are used. This latter, can be implemented in finite element standard codes.

  15. 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.

  16. 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 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)

  17. Selection of welding process to fabricate butt joints of high strength aluminium alloys using analytic hierarchic process

    International Nuclear Information System (INIS)

    Selection of welding process is an unstructured decision problem involving multiple attributes (factors). To provide decision support for the welding or design engineer, an all encompassing analysis of multiple attributes is necessary. The present paper reports a new procedure using an analytic hierarchic process (AHP) for the selection of a welding process to fabricate butt joints of high strength aluminium alloy of AA 7075 grade, based on the qualitative factors of welding processes, when the quantitative factors appear to be equal. The following three welding processes from arc welding family are generally used to fabricate high strength aluminium alloys: (i) gas metal arc welding (GMAW) (ii) gas tungsten arc welding (GTAW), and (iii) plasma arc welding (PAW). Of the three available processes, the best process has been selected by doing qualitative analysis with the help of AHP and in the present case, for welding high strength aluminium alloy, the best process is GTAW

  18. 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.

  19. 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.

  20. 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 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)

  1. Spark-anodized layers on aluminium alloy in tungstate-borate electrolytes

    International Nuclear Information System (INIS)

    Influence of pH and sodium tungstate concentration in solution of 0.4 M H3BO3 on specific features of formation, phase and elementary composition of coatings produced on aluminium alloy during its spark-anodized oxidation under galvanostatic conditions was studied using the methods of elementary and x-ray phase analyses, as well as 11B NMR of electrolyte solutions. It was shown that formation of tungsten oxide layers on the anodic surface stems from formation of heteropolyanions featuring composition [BW11O39H]8- and/or [BW12O40]5- in tungstate-borate electrolytes

  2. Direct chill and electromagnetic casting of aluminium alloys: Thermomechanical effects and solidification aspects

    OpenAIRE

    Drezet, Jean-Marie

    2000-01-01

    The tolerances of semi-continuously cast products of aluminium alloys are very critical if the scalping of the ingot faces is to be minimised before rolling. In the steady state regime of casting, the dimensions of the section of the solidified ingot are lower than those of the mould in the Direct Chill Casting (DCC) or of the inductor in the Electromagnetic Casting (EMC). The contraction of the section, several percents, is larger than the value associated with the thermal contraction of the...

  3. Spectrophotometric determination of yttrium in alloys containing nickel, aluminium, and chromium

    International Nuclear Information System (INIS)

    A method of photometric determination of yttrium in alloys containing nickel, aluminium, and chromium in a hundredfold excess in reference to yttrium, is described. It is based on the difference in pH values of complex formation of metal ions with Arsenazo III reagent. The procedure allows one to improve the selectivity of yttrium determination in the presence of interfering elements without their masking and to determine yttrium within its concentration range of 1.5-11 ?g/ml and with yttrium content in the samples down to 0.4 wt %

  4. 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...

  5. 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.

  6. 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.

  7. 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)

  8. 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.

  9. Research of aluminium alloy aerospace structure aperture measurement based on 3D digital speckle correlation method

    Science.gov (United States)

    Bai, Lu; Wang, Hongbo; Zhou, Jiangfan; Yang, Rong; Zhang, Hui

    2014-11-01

    In this paper, the aperture change of the aluminium alloy aerospace structure under real load is researched. Static experiments are carried on which is simulated the load environment of flight course. Compared with the traditional methods, through experiments results, it's proved that 3D digital speckle correlation method has good adaptability and precision on testing aperture change, and it can satisfy measurement on non-contact,real-time 3D deformation or stress concentration. The test results of new method is compared with the traditional method.

  10. The role of silicon in the corrosion of AA6061 aluminium alloy laser weldments

    International Nuclear Information System (INIS)

    The galvanic corrosion temporal increase observed on examination of the weld fusion zone (WFZ) of AA6061 laser weldments in 3.5 wt.% NaCl solution cannot be attributed to electron tunnelling as the surface oxide layer is too thick, or the presence of Cl- within the surface layer as this element was not found to be present. Aluminium alloy and WFZ galvanic and surface analyses indicate that the cathodic WFZ corrosion characteristics are due to increases in silicate concentrations in the surface oxide layer, leading to increased ionic and/or p-type semi-conductor conductivity, intermetallic concentrations and surface area.

  11. Influence of boron impurity in aluminium alloy construction material at criticality of RB reactor

    International Nuclear Information System (INIS)

    Evaluations of criticality benchmark cores of RB reactor are prepared in 1999-2001 for the International Criticality Safety Benchmark Evaluation Project. It was shown that the greatest contribution to uncertainty of the calculations and experimental data for criticality arose from uncertainty of contents of boron impurity in Yugoslav produced aluminium alloy (YuAl) of reactor construction material. Study of that particular issue was carried out in recent years and the results are shown in this paper with recommendation that new value for boron concentration in the YuAl material composition has to be used in criticality calculation, based on results of experimental and calculation evaluations. (author)

  12. 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.

  13. Some of the properties of plutonium and the aluminium-plutonium alloy

    International Nuclear Information System (INIS)

    1- Study of the physical properties of plutonium. 1) Study of the allotropy of plutonium. a) Thermal analysis: the apparatus used and the measurement technique are briefly described. The transition point temperatures and the corresponding heats of transformation have been determined. Finally, the results of the particular study of certain transition points are given. b) Dilatometry. The dilatometric analysis of the phase changes of plutonium has been carried out by means of the Chevenard dilatometer with photographic recording. The testing conditions (heating and cooling speeds, isotherm plateaux) have been varied in order to determine accurately the characteristics of each transition, particularly the ? ? ? transition on cooling. 2) Micrography of plutonium. For the accurate preparation of metallographic samples the electrolytic polishing must be rapid, which implies a mechanical polishing of excellent quality. Information is given on new attacking reagents which show the structure of the metal very clearly. 2- Study of aluminium-plutonium alloys. Comparative study of Al-Pu and Al-U alloys rich in aluminium. a) Thermal analysis. The liquids and fusion temperatures of the eutectic Al-XAl4, have been accurately determined. From the measurement of the heats of fusion the exact composition of the eutectic alloy has been determined. b) Thermal treatments. The eutectic coalescence kinetics have been studied by a micrographic method and by following the evolution of hardness. The results obtained show that the phenomenon is more rapid in Al-Pu alloys than in Al-U alloys. c) Micrographic study of the transition XAl3 ? XAl4. The peritectic reaction XAl3 + liq. ? XAl4 has been suppressed by quenching. The transformation of the XAl3 phase to the solid phase has been studied as well as the effect of small additions of silicon on the kinetics of this reaction. (author)

  14. Electrorefining of metallic U-Zr and U-Pu-Zr-alloy fuel onto solid aluminium cathodes in molten chlorides

    International Nuclear Information System (INIS)

    Electrorefining in molten LiCl-KCl using solid aluminium cathodes is considered as a promising pyrochemical method for reprocessing metallic nuclear fuel, represented by U-Zr and U-Pu-Zr alloys in this study. Actinide-aluminium (An-Al) alloys are produced on the cathode during the process, forming a dense deposit. The maximum loading of the electrode with the actinides as a function of the deposition conditions was investigated as were the selectivity and efficiency of the process. The electrodes were characterised by SEM-EDX analysis and 'gamma'-spectroscopy. (authors)

  15. The effects of temperature on the kinetics of aluminium evaporation from the Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    G. Siwiec

    2014-04-01

    Full Text Available In the paper, results of the study on temperature effects on the rate of aluminium evaporation from the Ti-6Al-4V alloy during smelting in a vacuum induction furnace are presented. During smelting at 1 973 – 2 023 K, 10 Pa and 100 Pa, up to 26 % reduction in the aluminium content in the alloy compared to the initial value is observed. The determined values of overall mass transport coefficient are 1,48?10-5 m?s sup>-1 – 1,95?10 sup>-5m?s sup>-1.

  16. B2-ordered iron-aluminium alloys strengthening. Influence of additions (Ni and B) and microstructure

    International Nuclear Information System (INIS)

    We study the effects of additions (Ni and B) and microstructure on the mechanical behaviour of 40 at. % Al iron-aluminium alloys. From a macroscopic point of view, we show that nickel reinforces FeAl alloys over the whole temperature range, but that it simultaneously leads to emphasize the room temperature brittleness of these alloys through a cleavage stress decrease. We confirm powder metallurgy grain refining interest to enhance yield stress as well as fracture resistance. We show that nickel-induced yield stress effect is additive to 'Hall-Petch' one. Also, we point out that the strengthening phenomena (nickel or grain size) cause the yield stress anomaly, which these alloys usually present, to be hidden. Through a dislocation structures analysis of deformed materials we precise that low temperature nickel-induced solid solution hardening (SSH) cannot be explained on the basis of classical SSH theories but more probably through nickel influence upon the Peierls stress. Moreover, we show that the APB tubes dragging model may be compatible with our microscopic and macroscopic results about the anomaly. Eventually, we put into relation a dynamic super-dislocations multiplication process observation (in situ transmission microscopy) with the nickel-containing alloys tendency to cleavage. (author)

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

    Science.gov (United States)

    Rabah, Mahmoud A

    2003-01-01

    The purpose of this work is to recover standard aluminium-magnesium alloy(s) and some valuable salts from used beverage cans (UBCs). The suggested method updated the current recycling technology by augmenting removal of the coating paint, decreasing magnesium loss during melting process and improving hydrochloric acid leaching of the formed slag. Iron impurity present in the leaching solution, was removed by oxidation using oxygen gas or hydrogen peroxide and filtered as goethite. Results obtained revealed that a mixture of methyl ethyl ketone/dimethyl formamide entirely removes the paint coating at room temperature. The process compares favorably to the current methods involving firing or swell peeling. The coating decomposes to titanium dioxide by heating at 750 degrees C for 30 min. Standard compositions of Al-Mg alloys are formulated using secondary magnesium. The extent of recovery (R) of these alloy(s) is a function of the melting time and temperature and type of the flux. The maximum (R) value amounts to 94.4%. Sodium borate/chloride mix decreases magnesium loss to a minimum. The extent of leaching valuable salts from the slag increases with increasing the molarity, stoichiometric ratio and leaching temperature of the acid used. Removal of iron is a function of the potential of the oxidation process. Stannous chloride has been recovered from the recovered and dried salts by distillation at 700-750 degrees C. PMID:12623092

  18. 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

  19. Relation between feeding mechanisms and solidification mode in 380 aluminium alloy with different iron contents

    International Nuclear Information System (INIS)

    In the present work the effect of iron (0.15, 0.42 and 0.86%) content in feeding mechanisms for 380 aluminium alloy has been studied. The feeding capacity has been evaluated by a device that produces a barrier removable to allowing the movement of the inter dendritic liquid. The results show the flow of different quantity of liquid, it depends of the temperature of operating the device and of the iron content. For minimum and maximum iron content, the inter dendritic and bursts feeding mechanisms are fundamentally involved, for 0.42% of iron the feeding mechanisms was the inter dendritic. The authors establish this behavior by the solidification mode of alloy, which promotes the presence of particles of Si or plates of b-Al3FeDi phase, in the inter dendritic channels and produce the different feeding mechanisms. (Author) 15 refs

  20. 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.

  1. Microstructure and texture evolution during accumulative roll bonding of aluminium alloy AA5086

    International Nuclear Information System (INIS)

    Highlights: ? The alloy AA5086 was accumulatively roll-bonded up to 8 cycles. ? The layered microstructure contains both elongated and equiaxed grains (?200-300 nm). ? Significant substructure formation inside layered microstructure leads to shear banding. ? Characteristic deformation texture evolution after ARB with individual texture bands. ? Anisotropic mechanical properties after ARB with improvement in strength but loss in ductility. - Abstract: In the present investigation, a strongly bonded strip of an aluminium-magnesium based alloy AA5086 is successfully produced through accumulative roll bonding (ARB). A maximum of up to eight passes has been used for the purpose. Microstructural characterization using electron backscatter diffraction (EBSD) technique indicates the formation of submicron sized (?200-300 nm) subgrains inside the layered microstructure. The material is strongly textured where individual layers possess typical FCC rolling texture components. More than three times enhancement in 0.2% proof stress (PS) has been obtained after 8 passes due to grain refinement and strain hardening.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, W., E-mail: wyman.zhuang@dsto.defence.gov.au [Aerospace Division, Defence Science and Technology Organisation, 506 Lorimer Street, Fishermans Bend, Victoria 3207 (Australia); Liu, Q.; Djugum, R.; Sharp, P.K. [Aerospace Division, Defence Science and Technology Organisation, 506 Lorimer Street, Fishermans Bend, Victoria 3207 (Australia); Paradowska, A. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2232 (Australia)

    2014-11-30

    Highlights: • Deep surface rolling as a post-repair enhancement technology was applied to the laser cladded 7075-T651 aluminium alloy specimens that simulated corrosion damage blend-out repair. • The residual stresses induced by the deep surface rolling process were measured. • The deep surface rolling process can introduce deep and high magnitude compressive residual stresses beyond the laser clad and substrate interface. • Spectrum fatigue test showed the fatigue life was significantly increased by deep surface rolling. - Abstract: 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.

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

    International Nuclear Information System (INIS)

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

  11. Study on corrosion of LT-21 aluminium alloy samples hung in reactor

    International Nuclear Information System (INIS)

    The corrosion performance of LT-21 aluminium alloy samples hung in HWRR (heavy water research reactor) is studied. Heavy water quality in reactor has been maintained according to water quality standards, in which [Cl-]?0.1 x 10-6, [Cu2+]?0.05 x 10-6. Temperature of the heavy water is 5?90 degree C. The flow velocity is 0.06 m·s-1. Heavy water was covered by helium. Exposure time of the samples, which were divided in five batches, hung in HWRR are about 1, 2, 3, 4, 5 a, respectively. Neutron fluence of the samples are 0.94 x 1021, 1.42 x 1021, 1.96 x 1021, 2.68 x 1021, 3.21 x 1021 n·cm-2, respectively. General corrosion rate of LT-21 aluminium alloy?1 ?m·a-1. Pitting corrosion was slight. The values of oxide film thickness on sample surface for five batches are 3.1, 5.7, 5.5, 10.0, 12.5, respectively

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

    International Nuclear Information System (INIS)

    Highlights: • Deep surface rolling as a post-repair enhancement technology was applied to the laser cladded 7075-T651 aluminium alloy specimens that simulated corrosion damage blend-out repair. • The residual stresses induced by the deep surface rolling process were measured. • The deep surface rolling process can introduce deep and high magnitude compressive residual stresses beyond the laser clad and substrate interface. • Spectrum fatigue test showed the fatigue life was significantly increased by deep surface rolling. - Abstract: 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

  13. 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.

  14. Structure and mechanical behaviour of an aluminium alloy AMg6 after severe plastic deformation and annealing: 2. Mechanical properties

    International Nuclear Information System (INIS)

    The peculiarities of the mechanical behavior at the room temperature of the AMg6 industrial aluminium alloy with submicro- and microcrystalline structures, obtained through intensive plastic deformation (IPD) by the equichannel angular pressing and subsequent annealing, are considered. The effect of the structural state on the discontinuous fluidity and characteristics of the alloy static strength, including crack resistance, is analyzed. The conclusion is made, that IPD of the AMg6 alloy increased its tensile properties at the room temperature. The obtained data, however, present no basis for the conclusion on the IPD favorable effect on the alloy plasticity

  15. Effects of cobalt, aluminium and potassium-boron additions on the performance of titanium based alloy electrodes

    International Nuclear Information System (INIS)

    In this paper, we report the study on the effects of cobalt, aluminium, and potassium-boron additions on the performance of titanium based hydrogen storage alloy electrodes. (1) The cycle life of Ti2Ni electrodes increases significantly with cobalt addition. Charge/discharge cycle life measurements show that the specific capacity of Ti2Ni electrodes increases with cobalt addition, reaches a maximum at a cobalt content of 0.67 at. % (Ti2Ni0.98Co0.02), and then falls with further addition. (2) The cycle life of Ti2Ni electrodes greatly increases with increasing addition of aluminium. The specific capacity of the electrode severely decreases with increasing aluminium content. (3) Addition of potassium-boron to Ti2Ni hydrogen storage alloy is effective in increasing the specific capacity and the charge/discharge cycle life of the electrode

  16. Positron annihilation spectroscopy as a tool to develop self healing in aluminium alloys

    International Nuclear Information System (INIS)

    Positron lifetime and Doppler broadening spectroscopy have been applied to probe the free volume generation (vacancies, dislocations and nano-cracks) during plastic deformation of a commercial aluminium AA2024 (T3) alloy. Aim of the total program is to study how solute atoms can be driven to the areas where initial cracking may occur in order to prevent the failure of the specimen. The phenomenon of closing the nano-crack is called Self Healing, and can provide extra strength and ductility to the alloy under some loading conditions. Plastic deformation of over-aged aluminum alloy at room temperature increases the average positron lifetime from initial value of 190 ps to 203 ps. The low momentum parameter S increases in agreement with the increase of open volume defects. The elastic deformation of the sample does not have a recordable effect on the positron annihilation data. It is also shown that the induced damage does not recover after loading the sample, i.e. the AA2024 in the T3 state is non self healing material, as expected, providing important first state result in the research of self healing Al alloys. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. The effect of strain rate on the microstructure of 2519A aluminium alloy plate impacted at 573 K

    International Nuclear Information System (INIS)

    The effect of strain rate on the microstructure of 2519A aluminium alloy plate impacted at 573 K was characterized by optical microscopy (OM) and transmission electron microscopy (TEM). Adiabatic shear lines, arc-like shearing bands and DRX grains due to the concentrated stress and heat were observed in impacted aluminum alloy plate. Highly regular dislocation networks due to dislocation climb and irregular dislocation networks pinned by the coarsened precipitates were obtained with the increasing strain rate.

  18. The effect of heat treatment on hardness and drye wear properties of a semisolid processed aluminium alloy

    OpenAIRE

    Menargues Muñoz, Sergi; Campillo Betbese, Manel; Baile Puig, Maria Teresa; Picas Barrachina, Josep Anton; Forn Alonso, Antonio

    2009-01-01

    Semisolid AlSiMg casting alloys are attractive alternatives for automotive and aeronautical applications. In this work the effects of heat treatments on hardness and tribological properties of A356 aluminium alloy obtained by Sub-Liquidus Casting (SLC) were studied. The optimum heat treatment conditions, in which the material presents the maximum hardening and wear resistance values, were determined. Heat treatment conditions investigated included: A356 SLC as cast, T5 and T6. Furthermore, AC...

  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. Alloy Designation, Processing, and Use of AA6XXX Series Aluminium Alloys

    OpenAIRE

    Prantik Mukhopadhyay

    2012-01-01

    The strength-to-weight ratio offered by AA6XXX alloys and their enhanced mechanical properties have become crucial criteria for their use in light weight military vehicles, rockets, missiles, aircrafts, and cars, used for both defence and civil purpose. The focus of this review paper is to put together the latest knowledge available from various sources on alloy design, industrial processing, development of properties, and potential use of AA6XXX alloys. The direct chill (DC) cast AA6XXX wrou...

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

    OpenAIRE

    SAVA?KAN, Temel; Gença?a PÜRÇEK

    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. Corrosion mechanisms of the AlFeNi aluminium alloy by water up to 250 deg

    International Nuclear Information System (INIS)

    Full text of publication follows: The AlFeNi aluminium alloy (1%Fe, 1%Ni, 1%Mg) will be used as nuclear fuel cladding in the Jules Horowitz research reactor. A better understanding of the corrosion mechanisms of this alloy in water is necessary to predict correctly the corrosion rate and the oxide thickness on the fuel plates. Corrosion tests in water at an average pH of 6.9 were hence performed on this alloy in static conditions at 70, 165 and 250 C, and in dynamic conditions at 70 C. The hydroxide film obtained on the samples corroded in autoclaves or at the slow flow rates is composed of two main layers: a dense and amorphous inner layer which grows by anionic diffusion and a porous crystalline outer layer which develops by cationic diffusion followed by a dissolution-precipitation process. The ratio of the amorphous oxide thickness to the corroded metal thickness decreases with corrosion time, thus indicating an increasing density of the amorphous oxide. Consequently, the diffusion through the inner oxide layer decreases drastically with corrosion time. The inner oxide thickness evolution is well described by a cationic diffusion model, with an apparent cationic diffusion coefficient decreasing exponentially with time. A comparison of the corrosion scales obtained in water and in vapour at 250 C showed that in the vapour, the outer precipitation oxide layer does not develop, and the inner oxide thickness is much lower. These results suggest that the anionic diffusion which controls the corrosion rate at the metal interface is coupled with the cationic diffusion and dissolution rate. The hydraulic conditions play therefore a dominant role in the corrosion rate. During dynamic experiments in once-through reactors at 70 C, the cationic release in the leaching water was measured at different times. Two leaching flow rates were used: 100 and 200 ml/h. After the first 3 hours, the aluminium and magnesium release follow a parabolic evolution, characteristic of a diffusion mechanism of these species. Because the magnesium does not precipitate in the outer oxide layer, its concentration in the water is much higher than that of the aluminium, and it is considered as a good tracer for the dissolution. It is shown that at 70 C, the apparent magnesium diffusion coefficient through the amorphous oxide increases with the flow rate. This apparent effect seems to be related to the flow rate dependence of the magnesium concentration at the water interface; indeed the cationic flux is proportional to the concentration gradient through the oxide scale

  3. 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...

  4. 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.

  5. 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 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)

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. Radiographic and ultrasonic testings of welded joints of 6063 aluminium alloy

    International Nuclear Information System (INIS)

    A study on evaluation of weld defects in aluminium butt joints was made in a comparative way through the radiographic and ultrasonic testing. This work was conducted with pipes 5 IPS (6,35 mm thickness) of 6063 aluminium alloy, circumferential TIG welded, due to the difficulty on performing non-destructive testing with this schedule. It was concluded thta ultrasonic testing has adequate sensitivity when setting gain adjustment is made with aid of a reference curve constructed by using a Reference Block (among others studied) with 1,5 mm dia. Hole as reference reflector, and a 5 MHz angle beam search-unit. In this case the ultrasonic testing is more accurate than radiographic testing to detect planar defects like lack of fusion and lack of penetration. Defect sizing by ultrasonic methods employed were 6 and 20 dB drop methods. In spite of your observed limitations concerning the establishment of the real size of defects, the procedure applied was precise for locate and define the weld defects that where found in this study. (author)

  11. Tribological Behaviour of W-DLC against an Aluminium Alloy Subjected to Lubricated Sliding

    Directory of Open Access Journals (Sweden)

    S. Bhowmick

    2015-09-01

    Full Text Available Diamond like carbon (DLC coatings mitigate aluminium adhesion and reduce friction under the ambient conditions but their tribological behaviour under lubricated sliding need to be further investigated. In this study, tribological tests were performed to evaluate the friction and wear characteristics of W-DLC and H-DLC coatings sliding against an aluminium alloy (319 Al under unlubricated (40 % RH and lubricated sliding conditions. For unlubricated sliding, coefficient of friction (COF values of H-DLC and W-DLC were 0.15 and 0.20. A lower COF value of 0.11 was observed when W-DLC was tested using lubricant oil incorporating sulphur while the H-DLC’s COF remained almost unchanged. The mechanisms responsible for the low friction of W-DLC observed during lubricated sliding were revealed by studying the compositions of the coating surfaces and the transfer layers formed on 319 Al. Micro-Raman spectroscopy indicated that the transfer layers formed during lubricated sliding of W-DLC incorporated tungsten disulphide (WS2.

  12. Microstructural evolution of aluminium/Al–Ni–Sm glass forming alloy laminates obtained by Controlled Accumulative Roll Bonding

    International Nuclear Information System (INIS)

    Highlights: • Elaboration of a UFG material by controlled ARB of Al/glass forming alloy multilayers. • Effect of the crystalline or amorphous nature of the reinforcement on the formability. • Investigation of the thermo-mechanical stability of the metallic glass. - Abstract: The current work deals with the early steps of the unprecedented elaboration of aluminium/Al based glass forming alloy laminates by only accumulative rolling at room temperature. The Al1?(x+y)NixSmy metallic glass forming alloy was introduced either in its original amorphous state or after total crystallization. This change of atomic structure, and therefore of both thermal and thermo-mechanical stability and mechanical behaviour, is shown to govern at once the processing parameters, the uniformity of the laminates microstructure and the bond strength at the matrix-reinforcement interfaces. The potential of the process so as to synthesize composite materials with a stable ultrafine structure is finally outlined

  13. Superficial modification of aluminium-base alloys (anodising and non-anodising) by silica coatings

    International Nuclear Information System (INIS)

    Transparent and colourless silica coatings were deposited on anadosing and non-anodising substrates of aluminium-base alloys (series 6063). Coatings were prepared by sol-gel (dipping method) from a silica alkoxide and a mixture of both silica alkolide and silica alkylalkoxide. Preparations were optimised from viscosity, density, surface tension, and contact angle measurements. Densification was carried out at 60 and 120 degree centigree. Reflectance attenuation of coated samples was analysed by UV-VIS-NIR spectroscopy. The results indicated that -10% of attenuation is reached. Durability and resistance against degradation tests of the metal/coating system were undertaken by immersion into aqueous solutions. Electrochemical impedance measurements and potential corrosion of the metallic substrate for variable times were performed. (Author) 7 refs

  14. Thermo-Mechanical Processing of Rapidly Solidified 5083 Aluminium Alloy - Structure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Tokarski T.

    2015-04-01

    Full Text Available Aluminium-magnesium 5083 alloy was rapidly solidified by means of melt spinning technique and plastically consolidated during subsequent hot extrusion process. As a result, rods 8 mm in diameter were obtained. Structure of as-extruded material is characterized by ultra-fined grains, which influences on increasement of mechanical properties of the material. The strengthening effect was further enhanced by application of thermo-mechanical treatment consist of cold rolling combined with isothermal annealing. As a result, reduction of grain size from ?710 nm to ?270 nm as well as enhancement of yield stress (330 MPa to 420 MPa and ultimate tensile strength (410 MPa to 460 MPa were achieved. Based on received results Hall-Petch coefficients (?0, k for 5083 RS material were determined.

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

    Science.gov (United States)

    Eslamian, S.; Sahari, B. B.; Ali, Aidy; Mahdi, El-Sadiq; Hamouda, A. M.

    2011-02-01

    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.

  16. 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

  17. Heat transfer and stress evolution behaviours of an aluminium alloy low pressure shell casting

    Science.gov (United States)

    Zhang, D. Q.; Zhou, J. X.; Chen, T.

    2015-06-01

    Considering the solidification, demoulding and heat treatment processes in low pressure casting, relatively complete processes of an aluminium alloy shell casting are simulated to investigate the heat transfer feature and stress behaviours variation of casting in each multi-processes stage. FDM is used to discrete thermal conduction model when studying the heat transfer process, while FEM is adopted to solve the elastic-plastic model when studying the stress behaviour variation. When matching the two models, we map the finite difference mesh to finite element mesh. Three different temperature conditions, namely 300 °C, 400 °C and 500 °C, are simulated when we research the influence of demoulding temperature on stress behaviour. The simulation results demonstrate that the higher demoulding temperature is, the greater casting deformation and the smaller stress value are. The final casting stress status and the initial heat treatment temperature have a different relationship as for different parts of casting.

  18. Finite element modelling of deformation behaviour in incremental sheet forming of aluminium alloy

    Directory of Open Access Journals (Sweden)

    Huang Tsung-Han

    2015-01-01

    Full Text Available In this paper, the finite element method (FEM is used to study the incremental sheet forming process of pyramidal shape. The material used is aluminium alloy 5052. The tool, a hemispherical ball-head with a diameter (d = 4?mm made of HSS tool steel, is used to press down on the sheet metal causing locally plastic deformation. The comparison between spiral tool path, spiral-step tool path and z-level tool path is carried out. Moreover, the final thickness distribution is investigated. The results indicate that the minimal thickness can be found on the corner of wall angle in SPIF process. Under the same step over, spiral-step tool path can obtain the deepest depth for pyramidal shape. The maximum formability for successful forming of the pyramidal shape with depth 60?mm is wall angles 65?.

  19. Cyclic deformation behavior of deep rolled as-quenched aluminium alloy AA6110 at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Juijerm, P.; Altenberger, I. [Kassel Univ. (Germany). Emmy Noether Group

    2007-06-15

    The as-quenched (solution-heat-treated) aluminium wrought alloy AA6110 (Al-Mg-Si-Cu) was mechanically surface treated (deep rolled) at room temperature. The deep rolled as-quenched AA6110 was cyclically deformed at room and elevated temperatures up to 250 C using stress-controlled push-pull fatigue tests. Cyclic deformation behavior and Woehler curves of the deep rolled as-quenched AA6110 have been investigated and compared to the polished condition as a reference. The effect of static/dynamic precipitation occurring during fatigue at elevated temperatures was analyzed and discussed. The stability of residual stresses as well as work hardening at elevated temperature was investigated using X-ray diffraction methods. Finally, from the S/N data, a borderline describing the effectiveness of deep rolling for different loading combinations in a stress amplitude-temperature diagram was established. (orig.)

  20. 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.

  1. Plastic anisotropy of ultrafine grained aluminium alloys produced by accumulative roll bonding

    Energy Technology Data Exchange (ETDEWEB)

    Beausir, B., E-mail: benoit.beausir@univ-metz.fr [Institut fuer Strukturphysik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Scharnweber, J. [Institut fuer Strukturphysik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Jaschinski, J. [Institut fuer Leichtbau und Kunststofftechnik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Brokmeier, H.-G. [GKSS Forschungszentrum, Max-Planck-Strasse, D-21494 Geesthacht (Germany); Oertel, C.-G.; Skrotzki, W. [Institut fuer Strukturphysik, Technische Universitaet Dresden, D-01062 Dresden (Germany)

    2010-05-25

    The plastic anisotropy of ultrafine grained aluminium alloys AA1050 and AA6016 produced by accumulative roll bonding (ARB) has been investigated by tensile deformation via the Lankford parameter. The average normal and planar anisotropies slightly increase (from 0.6 to 0.9) and decrease (from 0.6 to -0.7) as a function of ARB cycles, respectively. The global textures measured by neutron diffraction are used to simulate the Lankford and anisotropy parameters of the plates after 0, 2, 4, 6 and 8 ARB cycles with the help of the viscoplastic polycrystal self-consistent model. Simulation results are compared with those from experiment and discussed with regard to texture, strain rate sensitivity, grain shape and slip system activity.

  2. Recrystallization of Cold Worked Al-Al2 O3 Alloys and Commercial Purity Aluminium

    International Nuclear Information System (INIS)

    Recrystallization and grain growth of commercial purity aluminium and A1-A12 O3 alloys containing 0.6 and 1.0 wt.% A12 O3 have been studied after cold-rolling to a reduction of 90%. Heat treatment have been carried out in the temperature range 473 to 893 K and the annealing behavior of deformed specimens has been followed by microhardness testing, optical microscopy and X-ray diffraction studies. It has been observed that the presence of A12 O3 particles affects both the kinetics of recrystallization and the recrystallized grain size. It has also been found that the recrystallization temperature significantly can affect the grain size after recrystallization. These observations are analyzed and discussed on the basis of previous studies of the annealing behavior of deformed dispersion strengthened materials. 10 figs

  3. Mechanical spectroscopy of thermal stress relaxation in aluminium alloys reinforced with short alumina fibres

    Energy Technology Data Exchange (ETDEWEB)

    Carreno-Morelli, E.; Schaller, R. [Ecole Polytechnique Federale, Lausanne (Switzerland). Inst. de Genie Atomique; Urreta, S.E.

    1998-05-01

    The mechanical behaviour under low temperature thermal cycling of aluminium-based composites reinforced with short Al{sub 2}O{sub 3} SAFFIL fibres has been investigated by mechanical spectroscopy (mechanical loss and elastic shear modulus measurements). A mechanical loss maximum has been observed during cooling which originates in the relaxation of thermal stresses at the interfaces due to the differential thermal expansion between matrix and reinforcement. The maximum height increases with the volumetric fibre content. In addition, if the matrix strength is increased by the appropriated choice of alloy and thermal treatment, the maximum diminishes and shifts to lower temperatures. No damage accumulation at the interfaces has been detected during long period thermal cycling in the range 100 to 500 K. A description of the damping behaviour is made in terms of the development of microplastic zones which surround the fibres. (orig.) 9 refs.

  4. Protection against corrosion in marine environments of AA6060 aluminium alloy by cerium chlorides

    International Nuclear Information System (INIS)

    Lanthanide salts are being considered as an environmentally friendly alternative to the classic systems based on chromates. The addition of small concentrations of cerium chloride to aerated aqueous 3.5% NaCl solution inhibits uniform and pitting corrosion processes of AA6060. Full immersion tests combined with different electrochemical techniques were involved to determine the protection degree and the inhibition character supplied by the cerium ion. Their microscopic and compositional features have been analyzed using SEM and EDS spectra. The results obtained show that the protective layer has heterogeneous composition. An alumina layer covers the aluminium matrix while dispersed cerium-rich islands deposited over the cathodic sites of the alloy. In the case of AA6060, ?-Al(Fe,Mn)Si acts as permanent cathodic sites.

  5. 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

  6. Cerium-based conversion coatings to improve the corrosion resistance of aluminium alloy 6061-T6

    International Nuclear Information System (INIS)

    Highlights: • Cerium-based conversion coatings. • Cerium salt sources assisted with hydrogen peroxide. • Protective properties of the conversion coating. - Abstract: Cerium-based conversion coatings were deposited on aluminium alloy 6061-T6 by immersion in two cerium salt sources (chloride- and nitrate-based) assisted with hydrogen peroxide (H2O2). The morphology and composition of the coatings were analysed using scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrochemical measurements to assess corrosion behaviour were performed using free corrosion potential, polarisation and electrochemical impedance spectroscopy with a 3% NaCl solution. The influence of H2O2 on the generation of the coating was studied by cyclic voltammetry tests. The protective properties of the coating generated are heavily dependent upon the chelating effect, chaotropic anion, the pH and H2O2 content

  7. Analysis of the strain behaviour of a friction stir processed superplastic aluminium alloy

    Directory of Open Access Journals (Sweden)

    Sorgente Donato

    2015-01-01

    Full Text Available Superplastic forming is a well-established process by which very large, very complex shaped and also multi-sheets components can be manufactured in a single step. Combining this process with a suitable joining technique is of great industrial interest. In this work the strain behaviour of a friction stir processed aluminium alloy was investigated through free inflation tests. Principal parameters of the friction stir process were changed and free inflation tests were performed to assess the formability of the processed sheet. A strong influence of the friction stir process parameters was recorded on the formability of the processed material. Only a specified set of parameters assured a strain behaviour close to the one of the base material.

  8. Analysis of the Capabilities of a Hyperbolic Constitutive Equation for Al-5083 Superplastic Aluminium Alloy

    Science.gov (United States)

    Otegi, N.; Galdos, L.; Hurtado, I.; Leen, S. B.

    2011-05-01

    This paper describes the application of a hyperbolic, mechanisms-based constitutive equation set, modified to incorporate the effect of cavitation, to the prediction of the superplastic behaviour of a commercial Al-5083 superplastic aluminium alloy. The development of an algorithm for multi-stage identification of the complex set of constitutive parameters is presented and this approach is applied to characterise the constitutive behaviour of the Al-5083 at 500° C, based on constant strain-rate tensile test data. A large deformation, multiaxial formulation of the constitutive equation set is implemented and applied to finite element modelling of a bulge test forming process to characterise the cavitation evolution behaviour in the bulge test for different back pressure conditions.

  9. 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.

  10. 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

  11. Controlled grain size distribution and refinement of an EN AW-6082 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lampke, Thomas; Dietrich, Dagmar; Nickel, Daniela [Chemnitz Univ. of Technology (Germany). Inst. of Materials Science and Engineering; Bergmann, Markus [Chemnitz Univ. of Technology (Germany). Inst. for Machine Tools and Production Processes; Zachaeus, Rene [Fraunhofer-Institut fuer Werkzeugmaschinen und Umformtechnik (IWU), Chemnitz (Germany); Neugebauer, Reimund [Chemnitz Univ. of Technology (Germany). Inst. for Machine Tools and Production Processes; Fraunhofer-Institut fuer Werkzeugmaschinen und Umformtechnik (IWU), Chemnitz (Germany)

    2011-08-15

    An EN AW-6082 aluminium alloy was subjected to incremental deformation by a new process named gradation rolling. The process has been used to generate a grain size distribution in a rod-shaped billet. A grain size gradient ranging from coarse-grained in the billet core to ultrafine grained at the surface of the billet can be obtained. The grain size distribution has been confirmed by electron backscatter diffraction showing the grain refinement related to the true strain. The fibre texture of the base material has been transformed to a rolling texture in the surface region. This results in strain-hardening and grain-boundary strengthening in the surface region (130 HV0.5) as compared to the unchanged core material (110 HV0.5). (orig.)

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

    Directory of Open Access Journals (Sweden)

    Sancho Rafael

    2015-01-01

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

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

    Science.gov (United States)

    Sancho, Rafael; Cendón, David; Gálvez, Francisco

    2015-09-01

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

  14. 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.

  15. Corrosion of aluminium alloy test coupons in the TRIGA Mark III Research Reactor of Mexico

    International Nuclear Information System (INIS)

    The results of corrosion studies developed in the Instituto Nacional de Investigaciones Nucleares (ININ) are presented. The extent of corrosion of the aluminium alloy coupons exposed to the water of ININ TRIGA reactor pool was not significant. Few pits and oxides were observed on the coupon surfaces immersed for different times. This reduced extent of corrosion was similar to those on coupons exposed at other sites as per data obtained by visual inspection, metallographic analysis and image analysis. The water chemistry in the reactor pool was monitored throughout the duration of the project. The main parameters that influence the corrosion of Al alloy fuel cladding were measured. The conductivity of the water in the reactor pool was 1-3 ?S/cm, within recommended values to avoid corrosion. The chloride ion concentration was maintained below 1 ppm. Others ions (sulphates, calcium, nitrates) were also below 1 ppm. Another parameter that was measured was the amount of settled solids on coupon surfaces and their influence on corrosion. The sedimentation rate in the TRIGA Reactor pool was 17.66 ?g/cm2 and the sediment composition indicated iron oxides, aluminium-silicon compounds and some calcium carbonates. The sedimentation rate was similar in magnitude to that at other storage sites. However, the corrosion racks in the ININ TRIGA Reactor were exposed to high water flow rates, 1324.5 l/min. This high flow rate is considered to reduce the amount of deposited solids on coupon surfaces. The particles deposited on the coupon surfaces influenced pit initiation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk-Cieslak, Boguslawa, E-mail: badamczyk@inmat.pw.edu.pl; Mizera, Jaroslaw; Kurzydlowski, Krzysztof Jan

    2011-03-15

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

  17. Simulation calculations for the positron annihilation in aluminium alloys for the study of the segregate formation

    International Nuclear Information System (INIS)

    Highly solid aluminium alloys owe their properties to small, finely distributed segregations of alloy atoms. For the better understanding of the temperature treatment, which is required in order to control the segregate formation, it is important, to determine informations on the first early stages from few atoms. In the positron-annihilation spectroscopy (PAS) positrons are trapped in the vacancies of a solid and yield at their annihilation with surrounding electrons informations from their direct environment. because the formation of segregates requires a diffusion of the extraneous atoms by means of the vacancies, the PAS represents one of the few examination methods, by which already the formation of smallest segregations can be observed. By the comparison of measurement quantities of the PAS with simulations for different possible arrangements of extraneous atoms around the vacancy the atomic environment of the vacancy can be identified. In order to make this possible also in aluminium alloys, in which the number of the possible defect types is relatively large, a good description of the measurement values by the simulation is especially important. In the framework of this thesis the program AB2D was developed, by which the Doppler shift of the annihilation radiation can be determined. Contrarily to already existing approaches here valence-electron wave functions are used, which were calculated with the program ABINIT. By this way the main uncertainty by the description of the valence electrons in atomic superposition is cancelled. Because ABINIT is based on pseudopotentials, the projector augmented-wave method is used in order to describe the higher momenta of the electrons near the nuclei more realistically. With AB2D simulations for vacancy-extraneous-atom complexes and segregation phases in the alloy systems Al-Cu, Al-Mg-Cu, and Al-Mg-Si were performed. A comparison with measurements on samples, which were only few minutes stored at room temperature, showed thereby that the formation of first segregations in the environment of the vacancies runs very much faster than hitherto assumed.

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

    Science.gov (United States)

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

    2015-12-01

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

  19. High temperature oxidation of copper and copper aluminium alloys: Impact on furnace side wall cooling systems

    Science.gov (United States)

    Plascencia Barrera, Gabriel

    The high temperature oxidation behaviours of copper and dilute Cu-Al alloys were investigated. Experiments were carried out by: (i) Oxidizing under various oxygen potentials at different temperatures using a combined TG-DTA apparatus. (ii) Oxidizing in a muffle furnace (in air) at different temperatures for extended periods of time. The oxidation mechanisms were evaluated based upon the kinetic data obtained as well as by X-ray diffraction and microscopical (SEM and optical) analyses. It was found that oxidation of copper strongly depends on the temperature. Two distinct mechanisms were encountered. Between 300 and 500°C, the oxidation rate is controlled by lateral growth of the oxide on the metal surface, whereas between 600 and 1000°C oxidation is controlled by lattice diffusion of copper ions through the oxide scale. On the other hand, the partial pressure of oxygen only has a small effect on the oxidation of copper. Alloy oxidation is also dependent on the temperature. As temperature increases, more aluminium is required to protect copper from being oxidized. It was shown that if the amount of oxygen that dissolves in the alloy exceeds the solubility limit of oxygen in copper, an internal oxidation layer will develop, leading to the formation of a tarnishing scale. On the other hand if the oxygen content in the alloy lies below the solubility limit of oxygen in copper, no oxidation products will form since a tight protective alumina layer will form on the alloy surface. Surface phenomena may affect the oxidation behaviour of dilute Cu-Al alloys. Immersion tests in molten copper matte and copper converting slag, using laboratory scale cooling elements with various copper based materials, were conducted. Results from these tests showed that alloying copper with 3 to 4 wt% Al decreases the oxidation rate of pure copper by 4 orders of magnitude; however due to a significant drop in thermal conductivity, the ability to extract heat is compromised, leading to possible failures. Composite coolers were also tested and although their thermal conductivity is limited, they still are able to extract heat at a considerable rate.

  20. Rheological Analysis of Semi-Solid A380.0 Aluminium Alloy / Analiza W?a?ciwo?ci Reologicznych Stopu Aluminium A380.0 W Stanie Sta?o-Ciek?ym

    Directory of Open Access Journals (Sweden)

    Solek K.

    2015-12-01

    Full Text Available Knowledge of the rheological properties is crucial for the numerical modeling of technological processes. The main objective of this study was to conduct an analysis of the rheological properties of A380.0 (AlSi9Cu3(Fe aluminium alloy in the semi-solid state. The results could be used for identification of temperature range of the alloy, where thixoforming processes could be executed. Another purpose of the experimental work could be development of the mathematical models of the alloy apparent viscosity. The significant achievement of this particular study is an application of a viscometer which was specially designed for material tests executed at high temperatures, such as the measurement of liquid or semi-liquid aluminium viscosity. This paper presents the results of a rheological analysis of aluminium alloy.

  1. Mechanical properties of a superplastic formed aluminium alloy; Mechanische Eigenschaften von umgeformtem AA5083. Pruefung von partiell pressverschweissten und bei schmelzpunktnahen Temperaturen bearbeiteten Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Heine, B. [Fachhochschule Aalen (Germany). Materialkunde; Stuttgart Univ. (Germany). Korrosions- und Verschleissschutz fuer Luft- und Raumfahrtanwendung

    2002-07-01

    Aluminium alloys represent one possibility to realize a light-weight automobile body. Beside this near-net-shape-forming-techniques are a further way to reduce production costs. One way to realize it is superplastic forming (SPF). Unfortunately because of specific alloying techniques and thermomechanical treatments the costs for superplastic-formable alloys are several times the prize of conventional alloys. Aim of a project was to apply conventional aluminium alloy and to optimize the configuration forming temperature and forming rate so that SPF-typical elongations without localized reduction of wall-thickness could be reached. Until now SPF-comparable fracture-elongations of roughly 170% could be achieved. Contents of the poster will be the influence of the sheet material, forming temperature and forming rate to strength and fracture elongation, the interpretation of these effects by using microstructural mechanisms as well as illustrations of structural parts produced by using a conventional aluminium alloy. (orig.)

  2. Influence of casting defects on the endurance limit of aluminium and magnesium cast alloys; Einfluss von Gussfehlern auf die Dauerfestigkeit von Aluminium- und Magnesiumgusslegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, U.; Lipowsky, Hj.; Mayer, H.; Tschegg, S.; Zettl, B. [Institut fuer Meteorologie und Physik, Wien (Austria); Papakyriacou, M. [ARC Leichtmetallkompetenzzentrum Ranshofen GmbH, Ranshofen (Austria); Stich, A. [Audi AG, Ingolstadt (Germany)

    2002-03-01

    The influence of porosity (voids and shrinkage) on the fatigue properties at very high numbers of cycles is shown for the alloys AZ91 hp, AM60 hp, AE42 hp, AS21 hp and AlSi9Cu3 produced by high pressure die casting. Fatigue tests performed with ultrasonic equipment up to 10{sup 9} cycles show that these alloys exhibit a fatigue limit. The mean endurance limits (50% failure probability) of the magnesium alloys are 8-50 MPa and of the aluminium alloy 75 MPa. Fatigue cracks initiate at porosity, and whether a specimen fractures or not depends on the stress amplitude and the area and the site of the defect. Regarding the cast defect as an initial crack, a critical stress intensity value (K{sub cr}) may be found to propagate a crack until final failure. K{sub cr} of the magnesium alloys is 0,80-1,05 MPa{radical}(m), and 1,80 MPa{radical}(m) was found for AlSi9Cu3. Using K{sub cr} it is possible to correlate the probability of different defect sizes and the failure probability at different stress amplitudes. Additionally, predictions of the influence of rare large casting defects on the endurance limit are possible. (orig.)

  3. 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.

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Haboudou, A.; Peyre, P.; Vannes, A.B.; Peix, G

    2003-12-20

    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.

  6. 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.

  7. Characterisation of semi-solid deformation behaviour of aluminium-copper alloys via combined x-ray microtomography and nite element modelling

    OpenAIRE

    Fuloria, Devashish

    2009-01-01

    The production of aluminium sheet is expensive and energy intensive despite the reduced environmental impact during use. Twin roll casting is a method of directly producing aluminium alloys in near net shape directly to sheet at a fraction of the energy costs of conventional DC casting / hot rolling. It also requires a fraction of the capital cost. Although sheet can be produced, defects (segregates, surface bleeds, buckling, etc.) can arise which limit the range of alloys w...

  8. Microstructure and high temperature stability of age hardenable AA2219 aluminium alloy modified by Sc, Mg and Zr additions

    Energy Technology Data Exchange (ETDEWEB)

    Naga Raju, P. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)], E-mail: puvvala_nagaraju@yahoo.com; Srinivasa Rao, K. [Metallurgical Engineering Department, Andhra University, Visakapatnam 530003 (India); Reddy, G.M. [Defence Metallurgical Research Laboratory, Hyderabad 500258 (India); Kamaraj, M.; Prasad Rao, K. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)

    2007-08-25

    The present work pertains to the improvement of high temperature stability of age hardenable AA2219 aluminium-copper (6.3%) alloy. Addition of scandium, magnesium and zirconium to the base metal AA2219 was adopted to improve this high temperature stability. These additions were systematically varied by preparing alloys of different composition using gas tungsten arc melting. Long time ageing studies and impression creep technique were used to study the high temperature stability of the alloys. These modified compositions of the alloy resulted in fine equiaxed grains, refined eutectics, large number of high temperature stable and finer precipitates. Among all the compositions, 0.8% Sc + 0.45% Mg + 0.2% Zr addition was found to be significant in improving the high temperature stability of AA2219 alloy. This may be attributed to the possible microstructural changes, solute enrichment of the matrix and pinning of the grain boundaries by the finer precipitates.

  9. Microstructure and high temperature stability of age hardenable AA2219 aluminium alloy modified by Sc, Mg and Zr additions

    International Nuclear Information System (INIS)

    The present work pertains to the improvement of high temperature stability of age hardenable AA2219 aluminium-copper (6.3%) alloy. Addition of scandium, magnesium and zirconium to the base metal AA2219 was adopted to improve this high temperature stability. These additions were systematically varied by preparing alloys of different composition using gas tungsten arc melting. Long time ageing studies and impression creep technique were used to study the high temperature stability of the alloys. These modified compositions of the alloy resulted in fine equiaxed grains, refined eutectics, large number of high temperature stable and finer precipitates. Among all the compositions, 0.8% Sc + 0.45% Mg + 0.2% Zr addition was found to be significant in improving the high temperature stability of AA2219 alloy. This may be attributed to the possible microstructural changes, solute enrichment of the matrix and pinning of the grain boundaries by the finer precipitates

  10. 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.

  11. Microstructure and texture evolution during accumulative roll bonding of aluminium alloy AA5086

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Shibayan; Singh D, Satyaveer [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Suwas, Satyam, E-mail: satyamsuwas@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Kumar, S.; Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2011-11-15

    Highlights: {yields} The alloy AA5086 was accumulatively roll-bonded up to 8 cycles. {yields} The layered microstructure contains both elongated and equiaxed grains ({approx}200-300 nm). {yields} Significant substructure formation inside layered microstructure leads to shear banding. {yields} Characteristic deformation texture evolution after ARB with individual texture bands. {yields} Anisotropic mechanical properties after ARB with improvement in strength but loss in ductility. - Abstract: In the present investigation, a strongly bonded strip of an aluminium-magnesium based alloy AA5086 is successfully produced through accumulative roll bonding (ARB). A maximum of up to eight passes has been used for the purpose. Microstructural characterization using electron backscatter diffraction (EBSD) technique indicates the formation of submicron sized ({approx}200-300 nm) subgrains inside the layered microstructure. The material is strongly textured where individual layers possess typical FCC rolling texture components. More than three times enhancement in 0.2% proof stress (PS) has been obtained after 8 passes due to grain refinement and strain hardening.

  12. Constitutive modelling of creep-ageing behaviour of peak-aged aluminium alloy 7050

    Directory of Open Access Journals (Sweden)

    Yang Yo-Lun

    2015-01-01

    Full Text Available The creep-ageing behaviour of a peak-aged aluminium alloy 7050 was investigated under different stress levels at 174??C for up to 8?h. Interrupted creep tests and tensile tests were performed to investigate the influences of creep-ageing time and applied stress on yield strength. The mechanical testing results indicate that the material exhibits an over-ageing behaviour which increases with the applied stress level during creep-ageing. As creep-ageing time approaches 8?h, the material's yield strength under different stress levels gradually converge, which suggests that the difference in mechanical properties under different stress conditions can be minimised. This feature can be advantageous in creep-age forming to the formed components such that uniformed mechanical properties across part area can be achieved. A set of constitutive equations was calibrated using the mechanical test results and the alloy-specific material constants were obtained. A good agreement is observed between the experimental and calibrated results.

  13. The formation of surface segregates during twin roll casting of aluminium alloys

    International Nuclear Information System (INIS)

    When a certain productivity/casting speed is exceeded during twin roll casting, surface segregations form in a number of aluminium alloys with wide freezing ranges. Such segregations limit the productivity as mechanical properties and surface quality suffer during and after subsequent rolling and forming. Simulation results obtained by a 2-D thermo-mechanical model for twin roll casting, AlStrip, have been combined with studies in scanning electron microscope SEM/microprobe to assess the responsible mechanisms for the formation of segregates. The proposed mechanism consists of a sequence of events, where the initial source for the segregation is the progressive enrichment of alloying elements in the interdendritic liquid during solidification (microsegregation). Under certain conditions, i.e. when the critical productivity/casting speed is exceeded, low-pressure zones develop in the surface regions. Due to this pressure distribution, the enriched liquid flows through the coherent solid network to the surface, where solidification and the subsequent formation of segregations take place

  14. 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

  15. 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

  16. 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.

  17. Mechanical properties of scandium-alloyed aluminium alloys and their welded joints at cryogenic temperatures

    International Nuclear Information System (INIS)

    The paper gives results of studies on mechanical properties, fatigue characteristics and fracture of alloys 1560, 01535, 01570 and 01571 and their welded joints over the temperature range from 293 to 20 K. Also included are microstructural and fracture surface analyses

  18. Oxidation of an aluminium-magnesium alloy in liquid state. Methodology of determination of mechanisms from not necessarily repeatable experiments

    International Nuclear Information System (INIS)

    This research thesis reports the study of the oxidation of an aluminium-5 pc magnesium alloy in its liquid state in an oxygen environment, using thermogravimetric analysis and that of magnesium in its solid state. In a first part, the author reports a thermodynamic and bibliographical study on magnesium transformation in its solid state (Mg/O2 and Mg/H2O systems, transformation with dry and humid synthetic air, oxidation inhibitors) and on Al-Mg alloy transformation in presence of oxygen (thermodynamic properties of aluminium-rich Al-Mg alloys, Al-Mg/O2/N2 and Al-Mg/O2/N2/H2O systems). The next parts address the selection of reaction systems for the different cases (oxidation of solid magnesium in oxygen, oxidation of the Al-Mg alloy in oxygen), the modelling of the formation of magnesia from solid magnesium and from the Al-Mg alloy, and the modelling of the liquid Al-Mg A5182 alloy oxidation in oxygen

  19. The effects of mass transferin the liquid phase on the rate of aluminium evaporation from the Ti-6Al-7Nb alloy

    Directory of Open Access Journals (Sweden)

    L. Blacha

    2014-01-01

    Full Text Available In the present paper, the rate of aluminium evaporation from the Ti-6Al-7Nb alloy during smelting with the use of VIM method at 5 to 1 000 Pa and 1 973 to 2 023 K has been discussed. It has been observed that pressure reduction and temperature rise affect aluminium elimination from the alloy. Based on the determined values of overall mass transfer coefficients and mass transfer coefficients in the liquid phase, it has been found that the resistance related to aluminium mass transfer in the liquid phase is about 8 % of the overall process resistance.

  20. 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.

  1. 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.

  2. 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.

  3. Process Parameters Optimization of an Aluminium Alloy with Pulsed Gas Tungsten Arc Welding (GTAW) Using Gas Mixtures

    OpenAIRE

    Sashikant Janardan Morey; Kishor Purushottamrao Kolhe; Pawan Kumar; Chanchal Kumar Datta

    2011-01-01

    This paper demonstrates the enhancement of mechanical properties and effective optimization of pulsed GTAW process parameters on aluminium alloy 6061 using sinusoidal AC wave with argon plus helium gas mixtures. Modified Taguchi Method (MTM) was employed to formulate experimental layout and to study effect of process parameter optimization on mechanical properties of the weld joints. Microstructural characterization of weld joint was carried out to understand the structural property correlati...

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

    OpenAIRE

    Chobaut, N.; Carron, D.; Arsene, S.; Schloth, P.; Drezet, J. -M.

    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...

  5. Evaluation of the performance of coated and uncoated carbide tools in drilling thick CFRP/aluminium alloy stacks

    OpenAIRE

    MONTOYA, Maxime; CALAMAZ, Madalina; GEHIN, Daniel; GIROT, Franck

    2013-01-01

    This paper aims to establish the wear mechanisms of coated and uncoated tungsten carbide drills when drilling carbon fibre reinforced plastics (CFRP)/aluminium alloy (Al) stacks. During the drilling experiments, thrust forces were measured. A scanning electron microscope (SEM) and a numerical microscope, provided with a scanning device, were periodically used to analyse tool wear mechanisms and to measure wear progression of the tool cutting edges. For both coated and uncoated drills, abrasio...

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

    OpenAIRE

    K.Rajasuthan2; S.Raja,

    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...

  7. 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 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

  8. Effect of temperature and frequency of dynamic loading in the viscoelastic properties of aluminium alloy 7075-T6

    OpenAIRE

    Rojas Gregorio, José Ignacio; Aguiar, Albert; Crespo Artiaga, Daniel

    2011-01-01

    The viscoelastic response of a material offers an alternative method for analyzing its microstructure, phase transformations and fatigue behaviour. In this work, the viscoelastic properties of commercial aluminium alloy (AA) 7075-T6 are studied with a Dynamic-Mechanical Analyzer (DMA), and results are combined with Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) data. In accordance with this analysis, we propose an analytical model fo...

  9. Effects of Mould and Pouring Temperatures on the Ultimate Tensile Strength of Aluminium Alloy Sand Castings: An ANOVA Approach

    OpenAIRE

    Nosa IDUSUYI; Buliamin KAREEM; John O. OJI

    2011-01-01

    An analysis of the effects of sand casting process parameters on the ultimate tensile strength of an aluminium alloy sand casting based on the Analysis of variance (ANOVA) technique is proposed in this paper. While other casting parameters were kept constant, the selected parameters were varied and the cast specimen tested to obtain their ultimate tensile strength. Formulation of the varied effects was then made and a statistical tool selected for the analysis. The result of this work shows t...

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

    Science.gov (United States)

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

    2014-12-01

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

  11. Simulating the galvanic coupling between S-Al2CuMg phase particles and the matrix of 2024 aerospace aluminium alloy

    OpenAIRE

    Lacroix, Loïc; Blanc, Christine; Pébère, Nadine; Thompson, George; Tribollet, Bernard; Vivier, Vincent

    2012-01-01

    Study of the corrosion behaviour of a magnetron sputtered Al–Cu/Al–Cu–Mg model alloy couple in sulphate solutions has been undertaken to gain insight into the galvanic coupling between the matrix and SAl2CuMg particles in the 2024 aluminium alloy (AA2024). Polarisation curves and local electrochemical impedance spectroscopy measurements (LEIS) were performed on the individual alloys and on the model alloy couple. SEM enabled correlation of electrochemical phenomena to the observed damage. The...

  12. 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)

  13. Influence of surface lithium-aluminium alloy covering the anode of 3V lithium cells on their electric characteristics

    International Nuclear Information System (INIS)

    Reasons for the change in electric characteristics after a long shelf life of 3-volt lithium elements with (CF)-n, MnO2- and V2O5-cathodes and with anodes coated with lithium-aluminium alloy have been studied. It has been ascertained that in lithium elements with organic electrolyte the alloy on the anode promotes formation of gel-like reduced polymer solvent of the (AlOOLi)n type, which gives rise to increase in the electrolyte viscosity and decrease in electric capacity of the element during storage. 9 refs.; 4 tabs

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

    OpenAIRE

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

    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 surf...

  15. Comparative study of corrosion resistance of various aluminium alloys under water chemistry conditions of reactor MIR storage pool

    International Nuclear Information System (INIS)

    Aimed to reveal the regularities of corrosion behaviour for a number of aluminium alloys (1100, 6061, 6063, SAV-1) commonly used for research reactor fuel cans, the alloy specimens in the form of disk 3 mm thick, with diameters of 100 and 70 mm and a central orifice of 30 mm are placed into the aqueous medium of a spent fuel storage pool for long standing (up to 5 years). Disk of large and small diameters arranged in pairs are strung on a stainless steel 316 pipe using ceramic disks as spacers. Pairs of specimens consist as of similar so of dissimilar aluminium alloys. Two pairs have small disks of stainless steel 316. The results of specimens examination after 1.5 years of exposure are presented. It is stated that among the specimens of 100 mm diameter the least absolute gain in weight is obtained for a 6063 alloy/stainless steel 316 pair. A pair consisting of alloy 6061 only shows the least gain in weight among 70 mm diameter disks. It is marked that all data on gain in weight are described well by a parabolic curve. A preliminary conclusion is made that the main share of gain in weight is accounted for by contact surfaces

  16. Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper

    International Nuclear Information System (INIS)

    Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ

  17. Soudage homogène MIG de l'alliage d'aluminium 6061 MIG homogeneous welding of 6061 aluminium alloy

    OpenAIRE

    Benoit Alexandre; Paillard Pascal; Baudin Thierry; Mottin Jean-Baptiste

    2013-01-01

    Le soudage homogène (métal d'apport identique au métal de base) de l'alliage d'aluminium 6061 avec un procédé dit semi-automatique (MIG) n'a jamais été reporté jusqu'à maintenant dans la littérature. Nous montrons ici que l'utilisation d'un dérivé du procédé de soudage MIG, le MIG CMT (Cold Metal Transfer) permet d'obtenir des cordons de soudures sains (sans fissuration à chaud). De plus des traitements thermiques ont permis de retrouver partiellement ou de restaurer totalement les propriétés...

  18. Elastic and plastic properties of iron-aluminium alloys. Special problems raised by the brittleness of alloys of high aluminium content; Proprietes elastiques et plastiques des alliages fer-aluminium. Problemes particuliers poses par la fragilite des alliages a forte teneur en aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Mouturat, P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-06-01

    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) [French] Cette etude comporte les resultats obtenus avec des alliages fer-aluminium dont la composition s'etend de 0 a pres de 50 atomes pour cent d'aluminium. Nous avons etudie successivement les conditions d'elaboration et de transformation, le module elastique et la limite elastique; un dernier chapitre est consacre a l'etude du phenomene Portevin-le-Chatelier dans les alliages a 40 atomes pour cent d'aluminium. I) La principale difficulte a resoudre residait dans la fragilite intergranulaire des alliages ordonnes; celle-ci a ete considerablement reduite par des conditions appropriees d'elaboration et de transformation. II) Les etudes de module d'elasticite sont en rapport avec les diagrammes fer-aluminium; les temperatures de transformation sont bien mises en evidence. La formation de liaisons covalentes a partir de 25 atomes pour cent se traduit par des valeurs plus elevees du module. III) L'analyse des variations de la limite elastique en fonction de la-temperature fait apparaitre certaines relations avec les structures ordonnees, la presence de domaines anti-phases et l'existence de dislocations de surstructure. IV) Dans le domaine Fe Al ordonne, la cinetique du phenomene Portevin-le- Chatelier reposerait sur un mecanisme de diffusion lacunaire; nous avons precise leur role par l'influence qu'elles ont sur les dislocations, ce qui nous a conduit a l'ordre inhomogene de Rudman qui pourrait expliquer les crochets observes sur les courbes de traction. (auteur)

  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. Slow fatigue crack growth in aluminium and magnesium cast alloys in ambient air and in a vacuum; Langsames Ermuedungsrisswachstum in Aluminium- und Magnesiumgusslegierungen in Raumluft und in Vakuum

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, U.; Mayer, H.; Tschegg, S.; Zettl, B. [Vienna Univ. (Austria). Inst. fuer Meteorologie und Geophysik; Lipowsky, Hj.; Stich, A. [Audi AG, Ingolstadt (Germany); Papakyriacou, M. [ARC Leichtmetallkompetenzzentrum Ranshofen GmbH, Ranshofen (Austria)

    2002-01-01

    The influence of ambient air on near threshold fatigue crack growth in the magnesium cast alloys AZ91 hp, AM60 hp and AS21 hp and in the aluminium cast alloy AlSi9Cu3 has been investigated. Fatigue crack growth properties at a cycling frequency of 20 kHz in ambient air and in a vacuum are significantly different. In a vacuum, the threshold stress intensity amplitude of the aluminium alloy is 30% higher than in ambient air, and the threshold values of the magnesium alloys in a vacuum are up to 85% higher than in ambient air. Moisture of ambient air is responsible for accelerated crack growth at growth rates below 1 - 3 x 10{sup -9} m/cycle (AlSi9Cu3) and 2 - 5 x 10{sup -8} m/cycle (magnesium alloys), respectively. In ambient air a minimum crack growth rate of 5 x 10{sup -11} - 2 x 10{sup -10} m/cycle was observed, whereas far lower minimum growth rates were found in a vacuum. (orig.) [German] Die Arbeit beschaeftigt sich mit dem Einfluss des Umgebungsmediums Raumluft auf das sehr langsame Ermuedungsrisswachstum in den druckgegossenen Magnesiumlegierungen AZ91 hp, AM60 hp und AS21 hp und in der druckgegossenen Aluminiumlegierung AlSi9Cu3. Die bei einer Beanspruchungsfrequenz von 20 kHz gemessenen Rissausbreitungskurven in Raumluft und Vakuum unterscheiden sich im Schwellwertbereich deutlich. Der Schwellwert der Aluminiumlegierung liegt in Vakuum 30% hoeher als in Raumluft, und die Schwellwerte der Magnesiumlegierungen liegen bis zu 85% hoeher. Die in der Raumluft enthaltene Luftfeuchtigkeit ist massgeblich fuer die Beschleunigung des Risswachstums, wobei ein Einfluss bei AlSi9Cu3 bis zu Risswachstumsgeschwindigkeiten von 1 - 3 x 10{sup -9} m/Lastspiel und bei den Magnesiumlegierungen bis zu 2 - 5 x 10{sup -8} m/Lastspiel gefunden wird. In Raumluft wachsen Ermuedungsrisse mit einer Wachstumsgeschwindigkeit von mindestens 5 x 10{sup -11} - 2 x 10{sup -10} m/Lastspiel, waehrend in Vakuum auch wesentlich niedrigere Wachstumsraten gefunden wurden. (orig.)

  1. Fracture mechanics analyses of friction-twist welds in aluminium alloys; Bruchmechanische Untersuchungen an reibruehrgeschweissten Aluminiumlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Strombeck, A. v.; Dos Santos, J.F.; Torster, F.; Kocak, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1999-07-01

    The paper discusses metallographic analyses for determining the strength and hardness of welds made by combined friction and twist welding for joining 3-5 mm thick plates consisting of four different aluminium alloys (Al2024, Al 5005, Al 6061, Al 7020). Further tests for additional information include tensile tests with flat tensile microspecimens, fracture toughness measurements (CTOD {delta}{sub 5}) with weld-center-notched CT-50 specimens (a/W=0.5). The results from transverse tensile tests show that in welded zones of all but the Al 7020 specimens, there is a loss of strength, compared to the parent material. These results are confirmed by the tests in the flat tensile microspecimens. The fracture mechanics examinations reveal an increase in fracture toughness of the welds, compared to the parent material. This can primarily be attributed to the microstructural changes in the welded joints. Only in the alloy Al 2024 T351 no significant increase of this kind is observed. (orig./MM) [German] In dieser Arbeit wurden 3 mm und 5 mm starke Platten aus vier verschiedenen Aluminiumlegierungen (Al 2024, Al 5005, Al 6061, Al 7020) untersucht, die mit Hilfe des Reibruehrschweissverfahrens gefuegt wurden. Die erzeugten Schweissverbindungen wurden einer metallographischen Analyse unterzogen und auf Haerte und Festigkeitseigenschaften untersucht. Ergaenzt wurden diese Untersuchungen durch Zugversuche an Mikroflachzugproben. Bruchzaehigkeitsmessungen (CTOD {delta}{sub 5}) erfolgten an CT-50-Proben (a/W=0,5), wobei die Kerbposition in der Mitte der Schweissnaht lag. Die Untersuchungsergebnisse an Querzugproben zeigen, dass es bei allen untersuchten Legierungen ausser Al 7020 im Bereich der Schweissnaht zu einem Festigkeitsverlust im Vergleich zum Grundwerkstoff kommt. Diese Ergebnisse wurden durch die Tests an den Mikroflachzugproben bestaetigt. Die bruchmechanischen Untersuchungen belegen, dass die Bruchzaehigkeit des Schweissnahtbereiches gegenueber dem Grundwerkstoff in den meisten Faellen erhoeht wird. Dies kann im wesentlichen auf die mikrostrukturellen Aenderungen in diesem Bereich zurueckgefuehrt werden. Lediglich bei der Legierung Al 2024 T351 wurde kein signifikanter Anstieg der Bruchzaehigkeit in der Schweissnaht beobachtet. (orig.)

  2. 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.

  3. 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.

  4. 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.

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

    Science.gov (United States)

    Jovovi?, J.

    2014-12-01

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

  6. Ductile damage in aluminium alloy thin sheets: Correlation between micro-tomography observations and mechanical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Thuillier, S., E-mail: sandrine.thuillier@univ-ubs.fr [LIMATB, Universite de Bretagne-Sud-rue de Saint Maude BP 92116 56321 Lorient Cedex (France); Maire, E. [MATEIS CNRS UMR 5510, INSA Lyon-7 avenue Jean Capelle 69621 Villeurbanne Cedex (France); Brunet, M. [LaMCoS CNRS UMR 5259, INSA Lyon-7 avenue Jean Capelle 69621 Villeurbanne Cedex (France)

    2012-12-15

    This work deals with the characterization of ductile damage in an aluminium alloy AA6016-T4 by X-ray micro-tomography, as a function of anisotropy and triaxiality. Interrupted tensile tests on notched samples with three different geometries were performed and the void volume fraction was measured for different strain values, up to rupture. It was shown that void volume fraction evolution with the strain is rather similar at 0 Degree-Sign and 90 Degree-Sign to RD but at 45 Degree-Sign to RD it shows a more rapid evolution. Moreover, for the same strain level, a higher void volume fraction was recorded for a higher triaxiality ratio. Whatever the orientation and the stress triaxiality ratio, void volume fraction values range from 5 Multiplication-Sign 10{sup -4} up to 0.04. A numerical model based on Gurson-Tvergaard-Needleman constitutive equations was used to simulate the different tests. Hardening of the material was identified from macroscopic tensile test nucleation material parameters were identified by a direct method from void volume fraction evolution. It can be seen that the influence of triaxiality on void volume fraction is underestimated, though void growth is nicely predicted for the highest triaxiality ratio, for strains below 0.5. The load level was correctly predicted, except for high strain, where coalescence seems necessary to be taken into account.

  7. Removal of porosity in cast aluminium alloys by equal channel angular extrusion

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, P.W.J.; Lapovok, R.; Wells, P.; Raviprasad, K. [School of Physics and Materials Engineering, Monash Univ. (Australia)

    2003-07-01

    The study of recovery of porosity by equal channel angular extrusion (ECAE) can be important for manufacturers as ECAE makes an inexpensive tool for improvement of the quality of continuous and semi-continuous cast billets of aluminium alloys prior to manufacturing in forming processes. It has been shown that pores can change their form under shear deformation and be closed under negative hydrostatic pressure if the pressure exceeds some critical level. In this work, this critical pressure level was shown to be dependent on initial pore size and orientation. Samples for ECAE were cast with the defined level of porosity. They were extruded by an ECAE machine with different back-pressures to manipulate the different processing routes. The existence of pores before and after processing was studied using stero x-radiography. The shape of a pore was approximated by an ellipsoid or sphere, and transformation of that shape due to finite simple shear deformation has been considered by theoretical and experimental methods. The condition of recovery of a pore relevant to its initial size and orientation was obtained. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Gibilaro, M. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France); Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P.; Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite Paul Sabatier, 31062 Toulouse Cedex 9 (France)

    2009-03-05

    The electrochemical behaviour of AlF{sub 3} was investigated in LiF-CaF{sub 2} 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{sup -} = Al The electrochemical reduction is controlled by the diffusion of AlF{sub 3} 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: AlNi{sub 3}, AlNi, Al{sub 3}Ni{sub 2} and Al{sub 3}Ni. Layers with a uniform composition of AlNi{sub 3}, AlNi and Al{sub 3}Ni{sub 2} were prepared by varying the electrolysis potential, the current density and duration of intermetallic diffusion.

  9. 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

  10. 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.

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

    International Nuclear Information System (INIS)

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

  12. 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.

  13. Characterization of Deformed and As-cast Microstructure of Copper-Aluminium-Iron Alloys (?-Phase)

    Science.gov (United States)

    Pal, Hiranmay; Pradhan, Swapan Kumar; De, Madhusudan

    1993-03-01

    The microstructure of aluminium iron bronze, having nominal compositions Cu-1.5Fe-5Al, Cu-1.5Fe-10Al and Cu-1.5Fe-15Al (in at.%) has been characterized in the deformed and as-cast state by employing X-ray diffraction line profile analysis, microhardness studies, optical and scanning electron microscopy and magnetic susceptibility studies. From X-ray studies the stacking fault density has been found to increase with increasing Al concentration relative to binary Cu-Al depicting the influence of small presence of Fe in the ternary alloys. The X-ray results further predict that stacking fault energy is lowered due to the influence of small presence of Fe. The results of the microhardness studies corroborate the findings of the X-ray study. Optical and scanning electron microscopy (SEM) studies reveal the grain and grain boundary structures containing Fe-rich precipitates. These precipitates are primarily responsible for the ferromagnetic behaviour of the materials.

  14. Shock induced spall fracture in aluminium alloy "Al2014-T4"

    Science.gov (United States)

    Joshi, K. D.; Rav, Amit; Sur, Amit; Das, P. C.; Gupta, Satish C.

    2015-06-01

    The plate impact experiments have been carried out on 8mm thick target plates of aluminium alloy Al2014-T4 at impact velocities of 180 m/s, 290 m/s and 500m/s, respectively, using single stage gas gun facility. In each experiment, the of free surface velocity history of the sample plate is measured using VISAR instrument and utilized to determine the spall strength and dynamic yield strength of this material. The spall strength of 0.87 GPa, 0.97 GPa and 1.11 GPa, respectively, measured for impact velocities of 180 m/s, 290 m/s and 500 m/s with corresponding average strain rates varying from 1.36×104/s to 2.41×14/s has been found to display nearly linear dependence upon the strain rates. The dynamic yield strength with its value ranging from 0.395 GPa to 0.400 GPa, though, is higher than the quasi static value of 0.355GPa, appears to be relatively independent of impact velocities up to at least 500 m/s or equivalently strain rates up to ˜ 9.4×104/s.

  15. Precipitation of silicon in a solid quenched aluminium-silicon (1.3 at%) alloy studied by positron annihilation

    International Nuclear Information System (INIS)

    Doppler broadening of the positron annihilation line was measured for quenched and aged specimens of an aluminium-silicon (1.29 at% Si) alloy. One set of specimens was aged at room temperature (set A) and one set was isochronally (t = 30 min) aged at temperatures ranging from 347 to 884 K (set B). The lineshape parameter S measured in the as-quenched condition was larger than that of well-annealed pure aluminium. S decreased with time of ageing at room temperature, which might be ascribed to the formation of vacancy loops decorated with silicon atoms. After 1320 h at room temperature the specimens of set A were aged for 30 min at 353 K in vacuo. Then, the lineshape parameter S decreased further, which is interpreted as due to a further disappearance of the earlier formed vacancy loops. The behaviour of the lineshape parameter S for set B can be described as follows: 1. 350 to 450 K. Constant value of S, about the same as found for pure aluminium. 2. 450 to 580 K. Increase of S, ascribed to precipitation of vacancies near the Si aggregates/matrix interface relieving transformation strains. 3. above 580 K. Decrease of S to the pure-aluminium value. This efect is ascribed to the growth of silicon precipitates accompanied by annihilation of vacancies. The misfit between the silicon precipitates and the Al-rich matrix is accomodated by dislocations. (author)

  16. 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.

  17. Effect of aluminium on the passivation of zinc–aluminium alloys in artificial seawater at 80 °C

    International Nuclear Information System (INIS)

    Highlights: ? Pure Zn and Zn–Al alloys passivate and depassivate in artificial seawater. ? Al retards passivation of Zn–Al alloys. ? Passive film composes of the inner film and the outer charge transfer layers. ? Al increases current density but decreases corrosion resistance of passive films. ? Al increases the electrical conductivity and the capacitance of the films. - Abstract: The effect of Al (0.15, 0.3 and 1.0 wt.%) on the passivation of Zn–Al alloys in artificial seawater at 80 °C is investigated by electrochemical measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD). It is found that the presence of Al in Zn–Al alloys can retard passivation. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements show that Al increases the current density but decreases the corrosion resistance of passive films, respectively. Mott-Schottky analysis reveals that Al increases the electrical conductivity and the capacitance of the films. Passivation of Zn–Al alloys occurs in artificial seawater when the immersion time is between 120 and 288 h, due to the presence of various Zn and Al protective compounds at the surfaces. Depassivation occurs when the immersion time is between 288 and 720 h, probably due to the decrease of solution pH and the Cl? penetration mechanism.

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

    International Nuclear Information System (INIS)

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1-n-alkyl-3-methylimidazolium X- (X = BF4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF3SO3; n = 2 (IL4). X = (4-CH3C6H4SO3); n = 2 (IL5). X PF6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of ?-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations

  19. Electrorefining of U-Pu-Zr-alloy fuel onto solid aluminium cathodes in molten LiCl-KCl

    Energy Technology Data Exchange (ETDEWEB)

    Soucek, P.; Malmbeck, R.; Mendes, E.; Jardin, R.; Glatz, J.P. [European Commission, JRC, Karlsruhe (Germany). Inst. for Transuranium Elements; Cassayre, L. [Lab. de Genie Chimique (LGC), Univ. Paul Sabatier, UMR CNRS 5503, Toulouse (France)

    2008-07-01

    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)Al{sub 3} 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.)

  20. 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.)

  1. 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.

  2. Determination of hardness of AA 2024 aluminium alloy under ageing conditions by means of artificial neural networks method

    Energy Technology Data Exchange (ETDEWEB)

    Atik, E.; Meric, C. [Engineering Faculty, Celal Bayar Univ., Manisa (Turkey); Karlik, B. [Dept. of Computer Engineering, Halic Univ., Istanbul (Turkey)

    2004-07-01

    As known, 2XXX and 7XXX Aluminium wrought alloys can have high strength values by means of precipitation hardening heat treatment. Determination of the precipitation hardening conditions, which can give the most suitable strength values of an alloy, requires numerous tests. But the results of this process which require long time and high cost can be obtained in a shorter time and at a lower cost with less data by means of Artificial Neural Networks method. Since this method is used, less number of experiments and therefore less data are needed. Then other values are found by means of Artificial Neural Networks (ANN) method. This paper, presents the feed forward ANN to determine hardness of alloy for different temperatures. For this purpose, a classic Back-Propagation Algorithm was used that is structure as 1:2:4. (orig.)

  3. Quantum-to-continuum prediction of ductility loss in aluminium-magnesium alloys due to dynamic strain aging.

    Science.gov (United States)

    Keralavarma, S M; Bower, A F; Curtin, W A

    2014-01-01

    Negative strain-rate sensitivity due to dynamic strain aging in Aluminium-5XXX alloys leads to reduced ductility and plastic instabilities at room temperature, inhibiting application of these alloys in many forming processes. Here a hierarchical multiscale model is presented that uses (i) quantum and atomic information on solute energies and motion around a dislocation core, (ii) dislocation models to predict the effects of solutes on dislocation motion through a dislocation forest, (iii) a thermo-kinetic constitutive model that faithfully includes the atomistic and dislocation scale mechanisms and (iv) a finite-element implementation, to predict the ductility as a function of temperature and strain rate in AA5182. The model, which contains no significant adjustable parameters, predicts the observed steep drop in ductility at room temperature, which can be directly attributed to the atomistic aging mechanism. On the basis of quantum inputs, this multiscale theory can be used in the future to design new alloys with higher ductility. PMID:25087924

  4. 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

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    M. Br?na

    2011-01-01

    Full Text Available 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 recycling of metals has become an essential part of a sustainable industrial society. The process of recycling has therefore grown to be of great importance, also another aspect has become of critical importance: the achievement of quality and reliability of the products and so is very important to underst and the mechanisms of the formation of defects in aluminium melts, and also to have a reliable and simple means of detection.

  7. 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.

  8. 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.

  9. Effect of high homo-logical temperature on steam forming processes during superplastic deformation of aluminium-lithium 1420 alloy

    International Nuclear Information System (INIS)

    The processes of cavity formation in specimens of commercial aluminium-lithium alloy 1420 deformed under the optimum conditions of high-temperature superplasticity are studied. It is determined that the presence of the liquid particles on the interphase and intergrain boundaries leads to the formation of macroscopic discontinuities elongated along the tensile axis cavity in specimens during the superplastic deformation. Energy dispersion analysis of the chemical composition of fibers,which are formed from the liquid phase as a result of its viscous flow during the cavity opening, is made. It is determined that the fibers in solid state are riched of magnesia in comparison with the middle-equaled concentration of the aluminium based solid mixture

  10. Aluminium-stabilized multifilamentary superconductor and method of its manufacture

    International Nuclear Information System (INIS)

    A multifilamentary superconductor stabilized with pure aluminium is described comprising a plurality of ductile superconducting rods or wires (of Nb-Ti alloy) embedded in an aluminium alloy matrix, further enclosed in a sheath consisting essentially of pure aluminium. (author)

  11. 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.

  12. Effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded high strength aluminium alloy

    International Nuclear Information System (INIS)

    This paper reveals the effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded AA7075 aluminium alloy. This alloy has 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. 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. As welded joint strength is much lower than the base metal strength and hence, a simple aging treatment has been given to improve the tensile strength of the joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Post weld aging treatment is accompanied by an increase in tensile strength and tensile ductility

  13. 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.

  14. Deformation behaviour and microstructural development in 6061 aluminium alloy containing large Al2O3 particles at elevated temperature

    International Nuclear Information System (INIS)

    Hot deformation behaviour of 6061 aluminium alloy containing 15 vol.% of Al2O3 particles (average size 25 ?m) was studied in a temperature range of 200 to 500 deg C at constant strain rates 0.001-1s1. True stress-true strain curves of the composite shows that dynamic recovery is occurring during deformation at high temperature. Effect of temperature and strain rate on the deformation behaviour of the reinforced material was studied by evaluating stress exponent, n' and activation energy, Q. It was found that the reinforced material exhibited slightly higher n' and Q values than the unreinforced alloy. The composite displayed much higher strength compared to the monolithic alloy at low temperature and as temperature increased, the strength of the composite decreased rapidly, and the difference in the flow stresses for the two materials became smaller. Finer substructure was present in the reinforced alloy compared to the monolithic alloy under similar deformation conditions. Subgrain size was found to be inversely related to InZ (Z is temperature compensated strain rate) and flow stress, ?, for both reinforced and unreinforced alloys. 23 refs., 1 tab., 10 figs

  15. 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.

  16. 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

  17. Selective chelatometric titration of strontium in aluminium alloys with ((ethylenedioxy)diethylene dinitrilo)tetra-acetic acid

    International Nuclear Information System (INIS)

    Strontium is determined in aluminium alloys by chelatometric titration using ((ethylenedioxy)diethylene dinitrilo)tetra-acetic acid (EGTA, or Titriplex VI) as titrant and calcium solution as back-titrant, whilst different chelatometric indicators are compared. A liquid-liquid extraction procedure with sodium diethyl-dithiocarbamate as chelate and MIBK as organic solvent, combined with masking and correction methods are used to obtain better selectivity. The standard deviation and coefficient-of-variation have been found to be 3 ppm and (0.5-1.5%), respectively. (Author)

  18. 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.

  19. Optimization of squeeze casting parameters for non symmetrical AC2A aluminium alloy castings through Taguchi method

    International Nuclear Information System (INIS)

    This paper reports a research in which an attempt was made to prepare AC2A aluminium alloy castings of a non symmetrical component through squeeze casting process. The primary objective was to investigate the influence of process parameters on mechanical properties of the castings. Experiments were conducted based on orthogonal array suggested in Taguchi's offline quality control concept. The experimental results showed that squeeze pressure, die preheating temperature and compression holding time were the parameters making significant improvement in mechanical properties. The optimal squeeze casting condition was found and mathematical models were also developed for the process

  20. Optimization of squeeze casting parameters for non symmetrical AC2A aluminium alloy castings through Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Senthil, P. [Coimbatore Institute of Engineering and Technology, Coimbatore (India); Amirthagadeswaran, K. S. [Government College of Technology, Coimbatore (India)

    2012-04-15

    This paper reports a research in which an attempt was made to prepare AC2A aluminium alloy castings of a non symmetrical component through squeeze casting process. The primary objective was to investigate the influence of process parameters on mechanical properties of the castings. Experiments were conducted based on orthogonal array suggested in Taguchi's offline quality control concept. The experimental results showed that squeeze pressure, die preheating temperature and compression holding time were the parameters making significant improvement in mechanical properties. The optimal squeeze casting condition was found and mathematical models were also developed for the process.

  1. MIG welding and laser welding of die castings with welded profiles in aluminium alloys; Soudage MIG et soudage laser de pieces moulees sous pression avec des profils corroyes en alliages d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, S.; Rethmeier, M.; Wohlfahrt, H. [Brunswick Univ. Technique, Institut de Soudure (Germany)

    2003-11-01

    The welding of die castings offers a new perspective for the realization of complex structures of weak mass. For this reason, the use of die castings assembled by welding is currently a theme of research in the automotive industry. The welding of die castings is the most appropriate method for aluminium alloys. The MIG welding (metal inert gas welding) and TIG welding (tungsten inert gas welding) can be used for die castings with a lower gas amount. The use of laser welding is possible in the case where the process of die casting is optimized for the realization of castings with a very low gas amount. The laser-TIG welding is a method which has very specific advantages for die castings in aluminium alloys. The researches which are currently in progress reveal the very important influence of the type of aluminium alloy on the weldability of die castings. The alloys as AlSi seem to be better appropriate than the AlMg alloys for obtaining weldings of high qualities for die castings. (O.M.)

  2. Calculation of the s-n curve for cast aluminium alloys based on static tensile test and dendrite arm spacing; Berechnung der Woehler-Linie fuer Aluminium-Gusslegierungen aus dem statischen Zugversuch und dem Dendritenarmabstand

    Energy Technology Data Exchange (ETDEWEB)

    Stroppe, H. [Magdeburger Forschungsinstitut fuer Fertigungsfragen e.V. (MFF) am Institut fuer Fertigungstechnik und Qualitaetssicherung (IFQ) der Otto-von-Guericke-Universitaet Magdeburg (Germany)

    2009-10-15

    A fatigue life model based on fracture mechanics was developed in order to calculate the S-N curve for cast aluminium alloys due to the characteristic static tensile test values (0,2 % yield strength, tensile strength, elastic modulus) and to the secondary dendrite arm spacing of the casting structure. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Es wird ein bruchmechanisches Materialermuedungsmodell entwickelt, mit dem die Woehler-Linie fuer Aluminium-Gusslegierungen aus den Kenngroessen des statischen Zugversuchs 0,2 %-Dehngrenze, Zugfestigkeit und Elastizitaetsmodul sowie auch aus dem sekundaeren Dendritenarmabstand des Gussgefueges berechnet werden kann. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. Influence of hot working substructures on the room temperature mechanical properties in a commercial aluminium and aluminium-1% magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, H.; Rodriguez Ibabe, J.M.; Urcola, J.J. (Centro de Estudios e Investigaciones Tecnicas de Guipuzcoa (CEIT), San Sebastian (Spain))

    1991-01-01

    Isothermal hot deformation at constant strain rates by plane strain compression has been carried out in commercial Al and an Al-1% Mg alloy. The subgrain sizes after quenching the specimens immediately after the hot working have been measured for both materials by TEM, and correlated with the flow stress at high temperature. The proof stress at room temperature has also been measured by tensile testing, and has been correlated to the original subgrain size. The flow stress at different constant strains can be correlated to the subgrain size, being a contribution smaller for larger strains. As a consequence, the ductility, measured as the uniform elongation, is smaller as the subgrain size becomes smaller. (orig.).

  4. Combined Kelvin probe force microscopy and secondary ion mass spectrometry for hydrogen detection in corroded 2024 aluminium alloy

    International Nuclear Information System (INIS)

    The capability of Kelvin probe force microscopy (KFM) to detect and locate hydrogen in corroded 2024 aluminium alloy was demonstrated. Hydrogen was introduced inside the 2024 alloy following a cyclic corrosion test consisting of cycles of immersion in 1 M NaCl solution followed by exposure to air at ?20 °C. The combination of scanning electron microscopy, secondary ion mass spectrometry and KFM demonstrated that the grain and subgrain boundaries were preferential pathways for the short-circuit diffusion of hydrogen but also acted as a source of hydrogen diffusion in the lattice over distances of up to ten microns with non-negligible desorption when exposed to air at room temperature for 24 h

  5. Inhibitive effect of Ce(III) and La(III) cations for AA2219 aluminium alloy corrosion in sodium chloride medium

    Energy Technology Data Exchange (ETDEWEB)

    Venkatasubramanian, G., E-mail: venkatguru_1966@yahoo.co.in [Department of Chemistry, Sathyabama University, Jeppiaar Nagar, Chennai 600119 (India); Sheik Mideen, A. [Department of Chemistry, Sathyabama University, Jeppiaar Nagar, Chennai 600119 (India); Jha, Abhay K. [Materials Processing Division, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Thiruvananthapuram 695022 (India); Kulandainathan, M. Anbu [Electro Organic Chemistry Division, Central Electrochemical Research Institute, Karaikudi 630006 (India)

    2014-11-14

    In this paper, the rare earth chlorides were used to mitigate the dealloying of Al{sub 2}Cu intermetallic particles in aluminium alloy 2219-T87 plate exposed to 0.6 M NaCl solution. The negative shift of cathodic branches of potentiodynamic polarisation curves revealed the cathodic inhibition towards intermetallic dealloying. The low and high frequency time constants obtained from electrochemical impedance spectra revealed an increase in the corrosion resistance due to precipitation of rare earth oxides/hydroxides on the porous surface of native oxide film of aluminium alloy. Scanning electron microscopy coupled with energy dispersive X-ray analysis and atomic force microscopy revealed that intermetallic inclusions are the sites for the formation of cerium and lanthanum deposits which suppress copper redeposition and minimise galvanic interactions between the matrix and Al{sub 2}Cu particles. - Graphical abstract: Scanning electron microscopy and atomic force microscopy reveal the intermetallic inclusions, the sites for the formation of cerium and lanthanum oxide/hydroxide precipitates which prevent intermetallic de-alloying, suppress copper redeposition and minimise galvanic interactions in aluminium alloy 2219-T87 plate. - Highlights: • Ce{sup 3+} and La{sup 3+} act as cathodic inhibitors for AA2219-T87 aluminium alloy in 0.6 M NaCl. • Al{sub 2}Cu intermetallic particles are the sites for the formation of Ce and La precipitates. • The decrease in surface potential by rare earth chlorides confirms their inhibition.

  6. Inhibitive effect of Ce(III) and La(III) cations for AA2219 aluminium alloy corrosion in sodium chloride medium

    International Nuclear Information System (INIS)

    In this paper, the rare earth chlorides were used to mitigate the dealloying of Al2Cu intermetallic particles in aluminium alloy 2219-T87 plate exposed to 0.6 M NaCl solution. The negative shift of cathodic branches of potentiodynamic polarisation curves revealed the cathodic inhibition towards intermetallic dealloying. The low and high frequency time constants obtained from electrochemical impedance spectra revealed an increase in the corrosion resistance due to precipitation of rare earth oxides/hydroxides on the porous surface of native oxide film of aluminium alloy. Scanning electron microscopy coupled with energy dispersive X-ray analysis and atomic force microscopy revealed that intermetallic inclusions are the sites for the formation of cerium and lanthanum deposits which suppress copper redeposition and minimise galvanic interactions between the matrix and Al2Cu particles. - Graphical abstract: Scanning electron microscopy and atomic force microscopy reveal the intermetallic inclusions, the sites for the formation of cerium and lanthanum oxide/hydroxide precipitates which prevent intermetallic de-alloying, suppress copper redeposition and minimise galvanic interactions in aluminium alloy 2219-T87 plate. - Highlights: • Ce3+ and La3+ act as cathodic inhibitors for AA2219-T87 aluminium alloy in 0.6 M NaCl. • Al2Cu intermetallic particles are the sites for the formation of Ce and La precipitates. • The decrease in surface potential by rare earth chlorides confirms their inhibition

  7. Effects of surface treatment of aluminium alloy 1050 on the adhesion and anticorrosion properties of the epoxy coating

    Science.gov (United States)

    Sharifi Golru, S.; Attar, M. M.; Ramezanzadeh, B.

    2015-08-01

    The objective of this work is to investigate the effects of zirconium-based (Zr) conversion coating on the adhesion properties and corrosion resistance of an epoxy/polyamide coating applied on the aluminium alloy 1050 (AA1050). Field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectrum (EDS), atomic force microscope (AFM) and contact angle measuring device were employed in order to characterize the surface characteristics of the Zr treated AA1050 samples. The epoxy/polyamide coating was applied on the untreated and Zr treated samples. The epoxy coating adhesion to the aluminium substrate was evaluated by pull-off test before and after 30 days immersion in 3.5% w/w NaCl solution. In addition, the electrochemical impedance spectroscopy (EIS) and salt spray tests were employed to characterize the corrosion protection properties of the epoxy coating applied on the AA1050 samples. Results revealed that the surface treatment of AA1050 by zirconium conversion coating resulted in the increase of surface free energy and surface roughness. The dry and recovery (adhesion strength after 30 days immersion in the 3.5 wt% NaCl solution) adhesion strengths of the coatings applied on the Zr treated aluminium samples were greater than untreated sample. In addition, the adhesion loss of the coating applied on the Zr treated aluminium substrate was lower than other samples. Also, the results obtained from EIS and salt spray test clearly revealed that the Zr conversion coating could enhance the corrosion protective performance of the epoxy coating significantly.

  8. Some of the properties of plutonium and the aluminium-plutonium alloy; Quelques proprietes du plutonium et de l'alliage aluminium-plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Abramson, R.; Boucher, R.; Fabre, R.; Monti, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-07-01

    1- Study of the physical properties of plutonium. 1) Study of the allotropy of plutonium. a) Thermal analysis: the apparatus used and the measurement technique are briefly described. The transition point temperatures and the corresponding heats of transformation have been determined. Finally, the results of the particular study of certain transition points are given. b) Dilatometry. The dilatometric analysis of the phase changes of plutonium has been carried out by means of the Chevenard dilatometer with photographic recording. The testing conditions (heating and cooling speeds, isotherm plateaux) have been varied in order to determine accurately the characteristics of each transition, particularly the {delta} {yields} {gamma} transition on cooling. 2) Micrography of plutonium. For the accurate preparation of metallographic samples the electrolytic polishing must be rapid, which implies a mechanical polishing of excellent quality. Information is given on new attacking reagents which show the structure of the metal very clearly. 2- Study of aluminium-plutonium alloys. Comparative study of Al-Pu and Al-U alloys rich in aluminium. a) Thermal analysis. The liquids and fusion temperatures of the eutectic Al-XAl{sub 4}, have been accurately determined. From the measurement of the heats of fusion the exact composition of the eutectic alloy has been determined. b) Thermal treatments. The eutectic coalescence kinetics have been studied by a micrographic method and by following the evolution of hardness. The results obtained show that the phenomenon is more rapid in Al-Pu alloys than in Al-U alloys. c) Micrographic study of the transition XAl{sub 3} {yields} XAl{sub 4}. The peritectic reaction XAl{sub 3} + liq. {yields} XAl{sub 4} has been suppressed by quenching. The transformation of the XAl{sub 3} phase to the solid phase has been studied as well as the effect of small additions of silicon on the kinetics of this reaction. (author) [French] 1- Etude des proprietes physiques du plutonium. 1) Etude de l'allotropie du plutonium. a) Analyse thermique. On decrit brievement l'appareillage utilise et la technique de mesure. Les temperatures des points de transition et les chaleurs de transformation correspondantes ont ete determinees. Enfin, les resultats de l'etude particuliere de quelques points de transition sont exposes. b) Dilatometrie. L'analyse dilatometrique des changements de phase du plutonium a ete poursuivie a l'aide du dilatometre Chevenard a enregistrement photographique. On a fait varier les conditions de l'essai (vitesse de chauffe et de refroidissement, paliers isothermes, etc...) de maniere a preciser les caracteristiques de chaque transition notamment de la transition {delta} {yields} {gamma} au refroidissement. 2) Micrographie du plutonium. La preparation correcte des echantillons metallographiques exige une duree de polissage electrolytique tres courte, ce qui implique un polissage mecanique d'excellente qualite. On indique de nouveaux reactifs d'attaque qui revelent la structure du metal avec une grande nettete. 2- Etude des alliages aluminium-plutonium. Etude comparee des alliages Al-Pu et AI-U riches en aluminium. a) Analyse thermique. Les temperatures du liquidus et de fusion de l'eutectique Al-XAl{sub 4} ont ete precisees. La mesure des chaleurs de fusion a permis de determiner la composition exacte de l'alliage eutectique. b) Traitement thermique. La cinetique de coalescence de l'eutectique a ete etudiee par voie micrographique et en suivant l'evolution de la durete. Les resultats obtenus indiquent que le phenomene est plus rapide dans les alliages Al-Pu que dans les alliages AI-U. c) Etude micrographique de la transition XAI{sub 3} {yields} XAl{sub 4}. La reaction peritectique XAI{sub 3} + Iiq. {yields} XAI{sub 4} a ete supprimee par trempe. La transformation de la phase XAI{sub 3} a l'etat solide a ete etudiee ainsi que l'effet de faibles additions de silicium sur la cinetique de cette reaction. (auteur)

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

    Science.gov (United States)

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

    2013-05-01

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

  10. Non-destructive and three-dimensional measurement of local strain development during tensile deformation in an aluminium alloy

    Science.gov (United States)

    Kobayashi, M.; Miura, H.; Toda, H.

    2015-08-01

    Anisotropy of mechanical responses depending on crystallographic orientation causes inhomogeneous deformation on the mesoscopic scale (grain size scale). Investigation of the local plastic strain development is important for discussing recrystallization mechanisms, because the sites with higher local plastic strain may act as potential nucleation sites for recrystallization. Recently, high-resolution X-ray tomography, which is non-destructive inspection method, has been utilized for observation of the materials structure. In synchrotron radiation X-ray tomography, more than 10,000 microstructural features, like precipitates, dispersions, compounds and hydrogen pores, can be observed in aluminium alloys. We have proposed employing these microstructural features as marker gauges to measure local strains, and then have developed a method to calculate the three-dimensional strain distribution by tracking the microstructural features. In this study, we report the development of local plastic strain as a function of the grain microstructure in an aluminium alloy by means of this three-dimensional strain measurement technique. Strongly heterogeneous strain development was observed during tensile loading to 30%. In other words, some parts of the sample deform little whereas another deforms a lot. However, strain in the whole specimen was keeping harmony. Comparing the microstructure with the strain concentration that is obtained by this method has a potential to reveal potential nucleation sites of recrystallization.

  11. Effect of alloying with zinc on SFE of aluminium by study of lattice imperfections in cold worked Al–Zn alloys

    Indian Academy of Sciences (India)

    G Karmakar; R Sen; S K Chattopadhyay; A K Meikap; S K Chatterjee

    2002-08-01

    A detailed X-ray Fourier line shape analysis has been performed on three compositions of Al–Zn alloys viz. Al–3 55 wt% Zn, Al–14 7 wt% Zn and Al–19 3 wt% Zn in fcc phase. It has been found that deformation stacking faults, both intrinsic ' and extrinsic '' are absent in the cold worked state and twin fault is found to be slightly present in the deformed lattice of the two initial compositions of the alloys. Similar to the effect of solute germanium and copper, respectively in Al–Ge and Al–Cu systems, hexagonal zinc also fails to impart faulting in fcc Al–Zn system. This corroborates the fact that aluminium has high stacking fault energy.

  12. 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)

  13. On the mechanism of the anodic protection of aluminium alloy AA5182 by emeraldine base coatings

    International Nuclear Information System (INIS)

    Aluminium AA5182 coupons covered by a polyaniline film in the emeraldine base (EB) form showed increasing corrosion potential and decreasing corrosion current as a function of the thickness of the polymer layer. The cathodic reaction was proved not limited by diffusion of species inside the electrolyte solution and oxygen had no effect on the electrochemical behaviour of the coated samples. An EB coating on indium tin oxide conducting layer appeared slightly electroactive in neutral media. The IR spectra of aluminium coated samples, before and after heating in argon atmosphere, confirmed a redox reaction between the polymer film and the metal. This galvanic coupling can explain the good protective behaviour of emeraldine base against corrosion of aluminium

  14. 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

  15. 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.

  16. Equal-Channel Angular Pressing and Creeep in Ultrafine-Grained Aluminium and its Alloys.

    Czech Academy of Sciences Publication Activity Database

    Skleni?ka, Václav; Dvo?ák, Ji?í; Svoboda, Milan; Král, Petr; Kvapilová, Marie

    Rijeka : InTech, 2012 - (Zaki, A.), s. 3-45 ISBN 978-953-51-0861-0 R&D Projects: GA ?R(CZ) GAP108/11/2260; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : ultrafine-grained aluminium * ECAP * creep Subject RIV: JG - Metallurgy

  17. 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.

  18. 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)

  19. CeO2-filled sol-gel coatings for corrosion protection of AA2024-T3 aluminium alloy

    International Nuclear Information System (INIS)

    Hybrid organic-inorganic sol-gel-matrices, with up to 20 wt.% incorporated ceria nanoparticles, have been employed as coatings for an AA2024-T3 aluminium alloy. The morphology of the coatings and associated nanoparticles has been examined by conventional and high-resolution transmission electron microscopy, revealing a relatively uniform distribution of 5 nm size nanoparticles across the coating thickness. Electrochemical studies indicate a general beneficial effect of incorporation of ceria nanoparticles, although the performance of the coated alloy depends on the nanoparticle content. Electrochemical polarisation behaviour revealed that the coating decreased the anodic current density by about seven orders of magnitude compared with the uncoated alloy, with high breakdown potentials in chloride-containing solution. Accelerated salt spray testing showed that corrosion in an artificial scratch is blocked most efficiently by high ceria contents, whereas general corrosion is inhibited effectively with comparatively low ceria contents. Electrochemical impedance spectroscopy indicated degradation of the barrier properties of coatings with increased amounts of incorporated nanoparticles. Assessment of the abrasion and scratch resistance, and hydrophobicity also revealed additional beneficial functional properties of the coatings containing nanoparticles.

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

    Science.gov (United States)

    Purenovi?, J. M.; Randjelovi?, M. S.; Matovi?, B. Z.; Purenovi?, M. M.

    2015-03-01

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