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

Science.gov (United States)

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

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

2013-09-01

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

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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

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

International Nuclear Information System (INIS)

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

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Effect of hot and cold deformation on the {beta} fiber rolling texture in continuous cast AA 5052 aluminum alloy  

Energy Technology Data Exchange (ETDEWEB)

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

Liu, W.C. [Department of Chemical and Materials Engineering, Light Metals Research Laboratories, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)]. E-mail: wcliu@engr.uky.edu; Morris, J.G. [Department of Chemical and Materials Engineering, Light Metals Research Laboratories, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)

2005-06-15

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

Energy Technology Data Exchange (ETDEWEB)

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

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; Man, C.-S. [Department of Mathematics, University of Kentucky, 715 Patterson Office Tower, Lexington, KY 40506 (United States); Raabe, D. [Max-Planck-Institut fuer Eisenforschung, Microstructure Physics, Max-Planck-Str. 1, 40237, Duesseldorf (Germany); Morris, J.G. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)

2005-12-15

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

International Nuclear Information System (INIS)

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

8

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

9

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

Science.gov (United States)

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.

Theohari, S.; Kontogeorgou, Ch.

2013-11-01

10

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

International Nuclear Information System (INIS)

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

11

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

Energy Technology Data Exchange (ETDEWEB)

Commercially produced hot bands of AA 5052 continuous cast (CC) and direct chill (DC) cast aluminum alloys were cold rolled to (thickness) reductions of 70%, 80%, and 90% followed by annealing at different conditions. The recrystallization kinetics are found equivalent for both the CC and DC materials. Recrystallization microstructures are different between the CC and DC materials. Evolution of recrystallization texture in the CC and DC materials were investigated by using three-dimensional orientation distribution functions (ODFs) that were determined by X-ray diffraction. The recrystallization texture was correlated with cold rolling reduction (prior to annealing), annealing temperature, and annealing time. Results showed that the R {l_brace}124{r_brace}<211> and cube {l_brace}001{r_brace}<100> are dominant recrystallization texture components in both CC and DC materials. During annealing, the intensity and volume fraction of the cube component strongly depend on the prior cold rolling history. In contrast, the intensity and volume fraction of the R component remains almost constant regardless of the different cold rolling reductions prior to annealing. After complete recrystallization, the intensity and volume fraction of both R and cube components appear to be independent of the annealing temperature and annealing time.

Liu Jiantao [Material Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg MD 20899-8553 (United States) and Department of Chemical and Materials Engineering, University of Kentucky, Lexington KY 40506-0046 (United States) and Physics Department, Catholic University of America, Washington DC 20064 (United States)]. E-mail: jiantao.liu@alcoa.com; Morris, James G. [Department of Chemical and Materials Engineering, University of Kentucky, Lexington KY 40506-0046 (United States)

2004-11-15

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

International Nuclear Information System (INIS)

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

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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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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

Tiago Valdameri, Capelari; José Antônio Esmerio, Mazzaferro.

2009-09-01

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SURFACE MELTING OF ALUMINIUM ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

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Soldering of aluminium alloys  

International Nuclear Information System (INIS)

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

16

Hydrogen generation from aluminium corrosion in reactor containment spray solutions  

International Nuclear Information System (INIS)

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

17

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.)

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Investigation & Analysis of Different Aluminium Alloys t  

Directory of Open Access Journals (Sweden)

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

Nibedita Sethi*¹,

2014-01-01

19

Alloys of uranium and aluminium with low aluminium content  

International Nuclear Information System (INIS)

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

20

Characterization of Casting Defects in Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, typical defects in aluminium alloys cast by conventional pouring of liquid metal into a cylindrical alumina crucible and an induction melting process are characterized by using macroetching, optical microscopy and scanning electron microscopy. Oxide film defects are generated in both processing methods. Oxide films formed during casting are a major type of defect observed in the microstructures of aluminium alloys products. It has been found that pouring of molten metal into a ...

Wu, G.; O Reilly, K.; Galano, M.

2012-01-01

 
 
 
 
21

Heat resistant cast aluminium alloys with iron  

International Nuclear Information System (INIS)

On the base of structural approach principal possibility of development of cheaper high-iron cast heat resisting aluminium alloys is proved. Perspective Al-Fe-Ce-Zr-Cr and Al-Fe-Ni-Zr-Cr compositions are proposed. The alloys proposed have high heat resistance, mechanical and casting properties

22

Steam generated conversion coating on aluminium alloys  

DEFF Research Database (Denmark)

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.

Din, Rameez Ud; Jellesen, Morten Stendahl

23

Intermetallic phase particles in 6082 aluminium alloy  

Directory of Open Access Journals (Sweden)

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.

M. Wierzbiñska

2007-02-01

24

Potential for improved mechanical properties in cast aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Ba?ckman, Jonas; Svensson, Ingvar L.

1999-01-01

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Softening Behaviour of Selected Commercially Pure Aluminium Model Alloys  

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A characterization of the softening behaviour of four different commercially pure aluminium alloys has been carried out. The work is related to the MOREAL project (Modelling towards value-added recycling friendly aluminium alloys), where the main goal is to quantify the effect of the elements in recyclable aluminium alloys on microstructure and mechanical properties during thermo-mechanical processing. Typical elements are iron (Fe), silicon (Si) and manganese (Mn), and the alloys studied in ...

Sande, Gunnar

2012-01-01

26

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

1955-07-01

27

Neutron radiography of aluminium alloy corrosion damage  

International Nuclear Information System (INIS)

The results of a collaborative program between the Australian Atomic Energy Commission (AAEC) and the Aeronautical Research Laboratories (ARL) to evaluate the use of neutron radiography as a non-destructive technique for the detection and assessment of corroded aluminium alloys in aircraft structures are reported. A series of corroded aluminium alloy specimens was supplied by ARL for neutron radiography at the AAEC's Moata facility, a 100kW Argonaut type reactor. The specimens represented various aircraft structural configurations damaged by different types and levels of corrosion. An initial assessment of the sensitivity of neutron radiography for corrosion detection was performed using the Moata reactor. This evaluation was subsequently broadened to include assessments of neutron radiographs from thermal neutron reactor facilities and mobile sources in the USA

28

FSW characterization of 6082 aluminium alloys sheets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Mroczka, K.; Pietras, A.

2009-01-01

29

Thermophysical properties of cast aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermophysical properties of several binary aluminium - silicon alloys castings were studied using Differential scanning calorimetry and Dilatometry. In this research is investigated the behaviour of the material during the first heating after casting. The temperature range examined is 100 – 500 °C with a scan rate of 10 K/min. Therefore, only phase transformations of the solid-state are involved. The results have shown an evident thermal effect around 270 – 300 °C for all the samples i...

Mazzarini, Nicolo

2014-01-01

30

Weldability of aluminium alloy-1915  

International Nuclear Information System (INIS)

Weldability of the semi-finished sheets of 1915 alloy, 3.0 and 6.0 mm thick, with the extension of the weld test temperature range from -253 to 200 deg C is investigated. Weldability of 1915 alloy at argon-arc welding with the use of the non-consumable tungsten electrode is estimated by reference to its tendency towards formation of the crystallization cracks in accordance with the cross sample, mechanical properties of the welded joints, effect of deposit -welding on the mechanical properties of the welded joints. Within the temperature range of 200 to -196 deg C the strength characteristics of the welded joints continuously grow up, whereas at a temperature of -253 deg C these charactericteristics are somewhat reduced. It is established that the plastic characteristics of the welded joints and their sensitivity to notching become less at a temperature below -70 deg C. The ultimate resistance of the welded joints of 1915 alloy with AMG6N alloy is not less than 34 kgf/mm2, the bending angle is not less than 100 degrees

31

Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate  

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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

Bobic, B.; Mitrovic, S.; Babic, M.; Bobic, I.

2010-01-01

32

FSW characterization of 6082 aluminium alloys sheets  

Directory of Open Access Journals (Sweden)

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.

K. Mroczka

2009-12-01

33

Rapid titrimetric determination of scandium in aluminium alloys  

International Nuclear Information System (INIS)

A selective and simple complexometric method of 0.1-5% scandium determination in aluminium alloys without the alloy components isolation has been developed using xylenol orange as a reagent. Relative standard deviation amounted to 0.03-0.08

34

Roll casting of 5182 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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....

Haga, T.; Mtsuo, M.; Kunigo, D.; Hatanaka, Y.; Nakamuta, R.; Watari, H.; Kumai, S.

2009-01-01

35

TEM microstructure investigations of aluminium alloys used for laser alloying  

Directory of Open Access Journals (Sweden)

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.

K. Labisz

2012-12-01

36

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Birch, M.; Cowell, A.

1987-01-01

37

Manganese-aluminium complex alloy for steel reduction  

International Nuclear Information System (INIS)

Mn-Al(Ma) alloy for steel reduction has been developed and applied for 20 K and 12Kh1MF steels melting. MA alloy reduction is shown to promote a uniform distribution of aluminium, a decrease of sulfide contamination and oxygen content in steel, and to prevent the formation of lines of inclusions. It is noted that alloys with high manganese-to-aluminium content ratios provide the fastest purification from oxidation products

38

The diffusion of 65Zn in liquid aluminium alloys  

International Nuclear Information System (INIS)

The temperature and concentration dependences of the diffusion coefficients of 65Zn in aluminium and its alloys measured by radioactive tracer techniques are described. The adequate knowledge of diffusion processes is important in respect of the temperature and time parameters for the manufacturing process of aluminium alloys. The experiments involved the study of the diffusion accelerating effects of the alloying atoms of Mg, Zn, Cu and Si. Their characteristic coefficients increase in the order of Mg, Zn, Cu, Si. The explanation of the results, made by the aid of micro- and macroscopic models showed that non-transient metal impurities in aluminium caused only a slight degree of perturbation. (Sz.J.)

39

Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

40

Structure and thermodynamic properties of aluminium-lanthanum alloys  

International Nuclear Information System (INIS)

This article is devoted to structure and thermodynamic properties of aluminium-lanthanum alloys. Therefore, the microstructure and hardness of alloys are studied. By means of semiempirical formula and comparative evaluation the melting temperature of intermetallic compounds of present system is defined. The enthalpy rates of alloys dissolution in the calorimeter with isothermal cover are found.

 
 
 
 
41

Creep behaviour of the aluminium-nickel-alloys  

International Nuclear Information System (INIS)

Hypoeutectic Aluminium-Nickel alloys have been tested for creep in the range of high temperature. A time-dependent change of the structure is different for cast and extruded AlNi alloys. High deformation as extrusion at elevated temperature leads to a more stable structure in comparison with cast alloys. (orig.)

42

Thin-film cryogenic resistors from aluminium alloys  

Science.gov (United States)

The temperature dependence of the resistances of thin films sputtered from three commercially available aluminium alloys (5052, 5086, 5456) has been measured in the temperature range 1.5-4.2 K. The 5052-alloy films had a positive temperature coefficient of resistance (TCR) throughout this temperature range, whereas films of the other two alloys had a negative TCR.

Tadros, N. N.; Holdeman, L. B.

43

Investigation of aluminium and aluminium alloys by Moessbauer effect and positron annihilation  

International Nuclear Information System (INIS)

A general overview of the investigation of aluminium and some aluminium alloys by using Moessbauer spectroscopy and positron annihilation spectroscopy is presented. The detection of iron and cobalt impurities in aluminium, and the determination of Fe-Al bond by Moessbauer technique is described in detail. The various possibilities of positron annihilation spectroscopy, including 2? angular correlations, Doppler broadening, positronium detection, electronic structure studies, various lattice defect studies, investigations of Al-Zn, Al-Mg, Al-Mn, Al-Si, Al-Ge, Al-Sn alloys, vacancies, and surface studies are also presented. (R.P.)

44

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)

45

Potentiodynamic study of aluminium alloys with zinc and strontium  

International Nuclear Information System (INIS)

This article is devoted to influence of strontium additives on electrochemical corrosion of aluminium-zinc alloys in neutral medium. Study was conducted by means of potentiodynamic method in neutral medium of 3% NaCl.

46

Anodization of cast aluminium alloys produced by different casting methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Labisz, K.; Dobrzan?ski, L. A.; Konieczny, J.

2008-01-01

47

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

Scientific Electronic Library Online (English)

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

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

2009-12-01

48

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

Scientific Electronic Library Online (English)

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

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

49

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

Directory of Open Access Journals (Sweden)

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

Jean Robert Pereira Rodrigues

2009-12-01

50

Damage tolerance of aluminium alloys in aircraft applications  

Energy Technology Data Exchange (ETDEWEB)

The keen competition among airlines challenges the aircraft industry to continuously increase the economic efficiency of modern aircraft, in particular in terms of payload, range and long services intervals. This leads to aircraft with severely loaded structures requiring aluminium alloys with excellent damage tolerance properties. The lack of knowledge about the microstructural features controlling the crack growth behaviour and limited experience regarding the long term properties in recently developed aluminium alloys were the key drivers for starting the EU-project ''Investigation on Damage Tolerance Behaviour of Aluminium Alloys (IDA)'', which aims at the identification of the complex microstructure - crack growth relationship. Subject of the investigation are the alloy system AA2 x 24 (sheet and plate), AA6056 (sheet) and AA7449 (plate) and the alloy AA6056, examined also in the laser beam welded condition. Moreover, advanced simulation models for predicting fatigue crack growth based on microstructural features shall be developed. (orig.)

Reese, E.D. [EADS, Munich (Germany)

2004-07-01

51

Corrosion fatigue behaviour of 5083-H111 and 6061-T651 aluminium alloy welds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In addition to being one of the highest strength non-heat treatable aluminium alloys, magnesium-alloyed wrought aluminium 5083 displays excellent corrosion resistance and good weldability. Aluminium alloy 6061, alloyed with magnesium and silicon, displays high strength, excellent formability, adequate weldability and good corrosion resistance. These aluminium alloys find application in the ship building and transport industries where 5083 is often joined to 6061 to produce welded structures s...

Mutombo, Faustin Kalenda

2012-01-01

52

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A soldagem de ligas de alumínio sem degradação excessiva das propriedades originais do metal base apresenta-se como um obstáculo a ser superado pelas indústrias em seus processos de fabricação, uma vez que o alumínio tem sido usado cada vez de forma mais intensiva. Neste sentido, o processo de soldagem denominado Friction Stir Welding (FSW) tem recebido atenção por suas potencialidades onde o aporte de calor deve ser minimizado ou quando metais dissimilares devem ser soldados. Neste...

Tiago Valdameri Capelari; José Antônio Esmerio Mazzaferro

2009-01-01

53

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.

54

Behaviour of hydrogen impurity in aluminium alloys during anodizing  

International Nuclear Information System (INIS)

The present study examines the behaviour of hydrogen impurity in an Al-6.5 at.% W alloy during anodizing, using elastic recoil detection and nuclear reaction analyses. Increased concentrations of hydrogen are found near the alloy/anodic film interface, amounting to ?2x1015 H atoms cm-2 for the particular alloy, containing 0.1-0.3 at.% hydrogen in the bulk regions, and conditions of anodizing. The enrichment arises from hydrogen in the alloy (i) diffusing to the interface, which acts as a trap, or (ii) accumulating at the interface, due to the growth of the anodic film, or a combination of both processes. Diffusion is consistent with the known mobility of hydrogen in aluminium near ambient temperature. Further, accumulation, and subsequent oxidation, of hydrogen are expected based on the general behaviour of alloying elements in anodized aluminium. The anodic films contained ?0.1-0.3 at.% hydrogen, originating from either the electrolyte or the alloy

55

Use of acoustic energy in sand casting of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Puga, He?lder; Barbosa, J.; Oliveira, Joana

2013-01-01

56

Instrumental proton activation analysis of some aluminium and magnesium alloys  

International Nuclear Information System (INIS)

We have been made extensive systematic studies of the aluminium and magnesium light alloys by proton activation analysis (PAA) combined with y-ray spectrometry based on a germanium semiconductor detector. The incident energy of the projectiles has been chosen of the order of 11 MeV. We analyzed more than 10 types of light alloys. It has been shown that under our experimental conditions the determination of 25 chemical elements concentrations in aluminium alloys is possible. We have determined the traces of 16 chemical elements in magnesium alloys. The detection limits for Li, B, N, Na, Mg, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Mo, Ce, W, Pb are of the order of 0,1-1?g/g

57

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)

58

Residual stress magnitudes and related properties in quenched aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The surface and through thickness residual stress magnitudes present in heat treated high strength aluminium alloy components are frequently reported to exceed the uniaxial yield stress of small specimens of the same alloy measured immediately after quenching. In thick section plate and forgings, it is proposed that these high residual stress magnitudes are a consequence of hardening precipitation that occurs during quenching which allows a greater elastic stress to be supported. To investiga...

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

2006-01-01

59

Anisotropy and Inhomogeneity in Extrudates of Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Anisotropy and inhomogeneity of mechanical properties and texture of microstructure originating in hot extrusion process depend not only on the type of the alloy, state of the billet and extrusion parameters, but also on the shape and size of extrudates. Tensile properties in longitudinal and transversal directions of model extrudates having simple cross-sections have been tested on four types of aluminium alloys. Values of ultimate strength and yield stress in longitudinal direction are high...

Macek, K.; Oc?ena?s?ek, V.; Sedla?c?ek, V.

2000-01-01

60

Failures of dies for die-casting of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Kosec, B.

2008-01-01

 
 
 
 
61

Fast neutron activation analysis of silicon in aluminium alloys  

International Nuclear Information System (INIS)

The silicon content in an aluminium-silicon alloy was measured by nondestructive fast neutron activation analysis with fission spectrum neutrons. A boron nitride irradiation container reduced the flux of thermal and epithermal neutrons at the sample position, enhancing the 29Si(n,p)29Al reaction. A detection limit of 0.4% silicon in a 0.5 g alloy sample was obtained. (author)

62

Fast neutron activation analysis of silicon in aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The silicon content in an aluminium-silicon alloy was measured by nondestructive fast neutron activation analysis with fission spectrum neutrons. A boron nitride irradiation container reduced the flux of thermal and epithermal neutrons at the sample position, enhancing the /sup 29/Si(n,p)/sup 29/Al reaction. A detection limit of 0.4% silicon in a 0.5 g alloy sample was obtained.

Sorek, H. (Ford Motor Co., Dearborn, MI (USA)); Griffin, H.C. (Michigan Univ., Ann Arbor (USA). Dept. of Chemistry)

1983-01-01

63

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Directory of Open Access Journals (Sweden)

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.

Hamilta de Oliveira Santos

2005-06-01

64

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2005-06-01

65

Oxygen solubility and reactivity in Fe-Co-Ni-Cu alloys containing zirconium, hafnium and aluminium  

International Nuclear Information System (INIS)

Effect of zirconium, zirconium-aluminium, hafnium, hafnium-aluminium on oxygen activity Fe-Co-Ni-Cu alloys at 1600 deg C is investigated. Deoxidizing ability of zirconium and hafnium in Fe-Co-Ni-Cu alloys is lower, than in iron. Activity decrease of zirconium and hafnium in Fe-Co-Ni-Cu alloy, as opposed to pure iron, is explained by presence of cobalt, nickel and aluminium in alloy composition

66

Fatigue behaviour of 6061 aluminium alloy and its composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Hwa, Ping

2001-01-01

67

Research of Properties of Sprayed Coatings on the Aluminium Alloys  

Directory of Open Access Journals (Sweden)

Full Text Available In article the cathodic cleaning processes of aluminum alloyAW 5754 and cleaned substrate surface coating by plasmawith Ni-Cr-Fe-Si powder were researched. Aluminium substrateroughness after cathodic treatment at different cathodic treatmentparameters was established during the experiments. During theinvestigation a comparison of the calculated medium power1.6 to 9 kW plasma torch voltage-current characteristics withthe experimental results was made. The optimized parametersof aluminium cathode substrate cleaning process were selected;porosity and morphology of plasma sprayed nickel-based coatingwere determined.

Raimonda Lukauskait?

2014-02-01

68

TEM microstructure investigations of aluminium alloys used as coating substrate  

Directory of Open Access Journals (Sweden)

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

T. Ta?ski

2013-01-01

69

Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon  

Directory of Open Access Journals (Sweden)

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

T. Tchotang

2013-07-01

70

Aluminium alloys, properties and production for the automotive industry; Aluminium Werkstoffe und Herstellungsverfahren fuer den Automobilbau  

Energy Technology Data Exchange (ETDEWEB)

Aluminium-based materials, ie. self-hardening Al-Mg-Mn alloys and age-hardenable Al-Mg-Si alloys, are increasingly used in the automotive industry. The paper details specific properties of available materials and defined objectives of further development in order to meet special requirements. Various semi-finished rolled materials are used as examples illustrating the possibilities of varying and optimizing the material properties at the alloying and fabrication process steps, also referring to the metallurgical process of development of microstructure and the role of alloying elements and post-alloying treatments such as cold and hot rolling, or annealing, in this process. Recent new materials and applications are discussed in this context. (orig./cB) [German] Aluminium-Werkstoffe aus naturharten Al-Mg-Mn und aushaertbaren Al-Mg-Si Legierungen finden im Automobilbau z.Zt. in stetig zunehmendem Masse Verwendung. Die speziellen Eigenschaften und deren gezielte Weiterentwicklung zur Erfuellung besonderer Anforderungen werden vorgestellt. Ihre wesentlichen Eigenschaften sind ausreichend hohe Festigkeit, Korrosionsbestaendigkeit, gute Umformbarkeit und Schweissbarkeit. Ihr unterschiedlicher Erfuellungsgrad bestimmt die Auswahl der geeigneten Legierung. Dies und die Moeglichkeiten zur Beeinflussung und Optimierung der Eigenschaften durch Legierung und Fertigung werden am Beispiel von Walzhalbzeug dargestellt. Es wird auf die metallkundlichen Vorgaenge bei der Gefuegeentwicklung und deren gezielte Einstellung durch Legierungselemente und Steuerung des Fertigungsprozesses (Warm- und Kaltwalzen, Gluehbehandlungen) eingegangen. Die Ausfuehrungen werden an Beispielen aktueller Erfahrungen und neuen Anwendungen im Automobilbau erlaeutert. (orig.)

Hirsch, J. [Vereinigte Aluminium-Werke AG (VAW), Bonn (Germany)

2000-07-01

71

Cerium molybdate nanowires for active corrosion protection of aluminium alloys  

International Nuclear Information System (INIS)

Highlights: ? New methodology for synthesis of cerium molybdate nanowires is reported. ? Solutions with cerium molybdate nanowires provide inhibition to aluminium alloy 2024-T3. ? Inhibition associated with the formation of a thin dense barrier layer consisting of molybdenum oxides/hydroxides. - Abstract: In this paper the inhibitive performance of cerium molybdate nanowires prepared by a novel methodology is reported. The methodology is based on a low-temperature, controlled-rate mixing process. Structurally, cerium molybdate nanowires were found to be amorphous-like materials whose inhibiting action towards aluminium alloy 2024-T3 was demonstrated by DC polarization and electrochemical impedance spectroscopy (EIS), corroborated by microstructural surface analysis of the metallic substrate. The observed inhibiting action is attributed to the higher solubility of the cerium molybdate nanomaterials with respect to crystalline sodium cerium molybdate obtained at room temperature.

72

Results of the Experiment: Welding of Aluminium Alloy in Microgravity  

Science.gov (United States)

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

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

2002-01-01

73

Intermetallic phase particles in 6082 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Wierzbin?ska, M.; Mro?wka-nowotnik, G.; Sieniawski, J.

2007-01-01

74

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

DEFF Research Database (Denmark)

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 higher than in the pure Al. The amount of gas accumulation at grain boundaries was found to depend on gas generation rate, alloying and cold-work microstructure

Singh, Bachu Narain; Horsewell, Andy

1986-01-01

75

Reducing residual stress in 2014 aluminium alloy die forgings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Closed die forgings manufactured from 2014 aluminium alloys have been subject to both standard and non-standard heat treatments in order to reduce the as-quenched residual stress magnitudes. Warm water (60 degrees C) and boiling water quenches are investigated. The influence of changing the surface finish of the forgings during boiling water quenching on the mechanical properties and residual stress has also been determined. In addition, high temperature (200 degrees C) and dual aging treatme...

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

2008-01-01

76

Grain boundary phenomena and failure of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Haas, Marc-jan

2001-01-01

77

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.

78

Cavitation-aided grain refinement in aluminium alloys:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Atamanenko, T. V.

2010-01-01

79

Interaction of positrons with defects in aluminium alloys  

International Nuclear Information System (INIS)

Positron lifetime studies were performed on pure aluminium and on Al-Fe (0.1 wt%) and Al-Fe (0.05 wt%) alloys, heat treated in a broad temperature range. The results give evidence on the interactions between slowed-down positrons and structural defects. The annihilation parameters allowed conclusions to be drawn on the evolution of defect-patterns at different temperatures. (author)

80

Advances in recycling of wrought aluminium alloys for added value maximisation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent decades an increasingly large fraction of the world?s wrought aluminium alloys supply has come from the aluminium scrap recovered from industrial waste and discarded post-consumer items. The reason for that is the creation of an additional net surplus of the added value commenced from the production of wrought alloys. However, the replacing even a minor part of primary aluminium in wrought alloys with recycled counterpart originated from lower grades of scrap (typically scrap conta...

Kevorkijan, Varuz?an

2012-01-01

 
 
 
 
81

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Singh, R.

2011-01-01

82

LASER CLADDING ON ALUMINIUM BASE ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1991-01-01

83

Grain refinement of Aluminium alloys using friction stir processing  

International Nuclear Information System (INIS)

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

84

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

85

Corrosion and inhibition of medium-strength aluminium alloys  

International Nuclear Information System (INIS)

The use of chromates in aluminium alloys with aeronautical applications has been limited because of the high toxicity of these compounds. This has spurred intensive efforts to develop alternative effective and innocuous inhibitors. In this work, corrosion inhibition of a light and high strength. Al-Li-Cu alloy (8090) is studied in NaCl solutions with CeCl3 and LaCl3 lanthanide salts added. The corrosion rate is reduced at least one order of magnitude with concentrations between 100-10,000 ppm. SEM, EDS and XPS techniques are used to characterize the rare earth cations incorporated into the surface as oxide and hydroxides. (Author) 9 refs

86

Fatigue properties of particle reinforced aluminium alloys  

International Nuclear Information System (INIS)

In this work the particle reinforced Al-alloys 359 T6 + 20 % SiC and 2124 + 17 % SiC which differ significantly in their production and microstructure are investigated. Standard and in-situ tensile tests show, that in the powder metallurgically produced alloy 2124 reinforcement leads to a higher Young's modulus, yield and ultimate tensile stress where the cast alloy 359 + 20 % SiC exhibit increased stiffness, but low ductility due to cast porosity of some 100 ?m. The failure mechanism governed by microstructural parameters is found to play an important role for ductility. The fatigue properties are investigated with specific regard to the influence of the in-service condition (load ratio, temperature, variable amplitude loading) in the foreseen applications in the automobile- and aerospace industry. Standard fatigue tests point out that the endurance limit is improved by reinforcement, but is strongly dependent on the size of given initial defects. The fatigue crack properties are characterised by standard crack growth curves and r(esistance)-curves for the threshold of stress intensity factor range. Both composites exhibit a higher effective threshold than their unreinforced alloys. Furthermore the fatigue resistance described by the R-curve as well as the long crack threshold are improved in the alloy 2124 + 17 % SiC. While in crack growth tests under constant amplitude loading the alloy 2124 + 17 % SiC shows lower crack growth rates than its unreinforced alloy, the opposite case is in the alloy 359 + 20 % SiC at high DK. Periodic overloads lead in the 359 + 20 % SiC to particle fracture at the crack tip and to a steeper increase in the crack growth rate. In the 2124 + 17% SiC the fatigue crack grows predominately in the matrix and a retardation effect due to overloads is observed. In order to describe the fatigue limit of components as a function of initial defect size an analytical concept is developed assuming that the fatigue limit is controlled by the condition of propagation/non-propagation of given small defects. The dependence of the threshold on the crack length is taken into account by the experimentally determined R-curves. The R-curve concept is applied on both composites to describe the influence of microstructure and load ratio on the fatigue limit. The model is assessed and successfully validated by fatigue tests on standard specimens and component testing. (author)

87

Wear of conventional and experimental aluminium bearing alloys sliding under lubrication  

Energy Technology Data Exchange (ETDEWEB)

Two compositions of aluminium alloys Al-1.2 wt.% Cu-0.9 wt.% Ni-0.7 wt.% Si and Al-1.1 wt.% Cu were chosen to produce conventional bearing alloys with about 6 and 20 wt.% of tin respectively and other two alloys with same basic compositions were produced using lead as dispersoid in same amount instead of tin. The alloys were prepared by impeller mixing and bottom discharge chill casting technique. Their density, microstructure, mechanical properties were evaluated at room temperature. Sliding wear characteristics of these alloys under lubrication were studied in detail. Debris and worn surface analysis was also done. Tin and lead decreased tensile and compression strength of aluminium matrix alloys, percentage elongation was increased in both the cases. Strength properties of aluminium-tin alloys are slightly more than the equivalent experimental aluminium-lead alloys. Wear rate of leaded alloys is lower than the aluminium-tin alloys. Leaded aluminium bearing alloys exhibit superior wear resistance with slightly lower mechanical properties, to that of aluminium-tin alloys. (orig.)

Pathak, J.P.; Mohan, S. [CAS, Dept. of Met. Engg., BHU, Varanasi (India)

2005-03-01

88

Corrosion-electrochemical and mechanical properties of aluminium-berylium alloys alloyed by rare-earth metals  

International Nuclear Information System (INIS)

In order to study influence of rare earth metals on corrosion-electrochemical and mechanical properties of aluminium-berylium alloys the alloys contain 1 mass % beryllium and different amount of rare earth metals were obtained.-electrochemical and mechanical properties of aluminium-berylium alloys. The electrochemical characteristics of obtained alloys, including stationary potential, potentials of passivation beginning and full passivation, potentials of pitting formation and re passivation were defined.

89

Improving the wettability of 2024 aluminium alloy by means of cold plasma treatment  

Science.gov (United States)

Aluminium alloys are heavily used to manufacture structural parts in the aeronautic industry because of its lightness and its corrosion resistance. These alloys are successfully used in other industrial fields too, such as railway, automotive and naval industries. The need to contrast the severe use conditions and the heavy stresses developing in aeronautic field implies to protect the surfaces of the structures in aluminium alloy by any deterioration. To preserve by deterioration, it is necessary to make aluminium more suitable to be coated by protective paint. In the aeronautic industry, a complex and critical process is used in order to enhance both wettability and adhesive properties of aluminium alloy surfaces. Cold plasma treatment represents an efficient, clean and economic alternative to activate aluminium surfaces. The present work deals with air cold plasma treatment of 2024 aluminium alloy surfaces. The influence of dc electrical discharge cold plasma parameters on wettability of 2024 aluminium alloy surfaces has been studied. A set of process variables (voltage, time and air flow rate) has been identified and used to conduct some experimental tests on the basis of design of experiment (DOE) techniques. The experimental results show that the proposed plasma process may considerably increase aluminium alloy wettability. These results represent the first step in trying to optimise the aluminium adhesion by means of this non-conventional manufacturing process.

Polini, W.; Sorrentino, L.

2003-05-01

90

Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite  

International Nuclear Information System (INIS)

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

91

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

92

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.)

93

Anodization of cast aluminium alloys produced by different casting methods  

Directory of Open Access Journals (Sweden)

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.

K. Labisz

2008-08-01

94

A central role in automobile evolution - aluminium alloys and magnesium alloys  

Energy Technology Data Exchange (ETDEWEB)

The history of evolution in automobiles has been one of a continuing endeavor to increase speed, safety and efficiency. Aluminium alloys and other lightweight materials have served a central role in this evolution. This paper reviews the evolutionary process of aluminium alloys and magnesium alloys and how practical applications have been developed. It is important that economic factors be taken adequately into consideration for an automotive material when enhancing performance or function. Up until now, new alloy compositions have been found through a crystallographic or electron theory approach. It is also vital that the part shaping process be taken into consideration when deliberating practical application of a new material composition to an automotive component. (author)

Noguchi, M.; Shiina, H.; Suzuki, T. [Honda R and D Co. Ltd. (Japan)

1999-07-01

95

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

96

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)

97

Laser surface alloying of aluminium-transition metal alloys  

Directory of Open Access Journals (Sweden)

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

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

Almeida, A.

1998-04-01

98

Friction stir welding of 6061 aluminium alloy  

International Nuclear Information System (INIS)

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

99

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.

100

Anisotropy and Inhomogeneity in Extrudates of Aluminium Alloys  

Directory of Open Access Journals (Sweden)

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

K. Macek

2000-01-01

 
 
 
 
101

Frictional conditions between alloy AA6060 aluminium and tool steel  

International Nuclear Information System (INIS)

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

102

Frictional conditions between alloy AA6060 aluminium and tool steel  

Science.gov (United States)

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

Widerøe, Fredrik; Welo, Torgeir

2011-05-01

103

Failures of dies for die-casting of aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available 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 temperature fields on the working surface of the testing die were checked through thermographic measurements, and failures and cracks on the working surface of the die were analysed with non-destructive metallographic examination methods.

Kosec, B.

2008-01-01

104

THE SAFETY OF MOLTEN ALUMINIUM-LITHIUM ALLOYS IN THE PRESENCE OF COOLANTS  

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The conventional, large scale techniques employed for casting fabrication ingot in aluminium alloys allow, in certain circumstances, the molten alloy to come into contact with water. Industry codes of practice have been developed that reduce the likelihood of explosions in these "run-out" situations to a very low level. It has, however, been demonstrated that the hazard is much greater when aluminium alloys containing lithium come into contact with water. This paper describes experiments to a...

Page, F.; Chamberlain, A.; Grimes, R.

1987-01-01

105

Characterization and structure of precipitates in 6xxx Aluminium Alloys  

International Nuclear Information System (INIS)

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

106

Fracture toughness behaviour of FSW joints aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2000-07-01

107

Electron beam welding of aluminium-beryllium-magnesium system alloy  

International Nuclear Information System (INIS)

Experimentally studied was the effect of the conditions of vaporization of a metal in the fusion zone and that of the variation of the chemical composition of the said metal upon the character of formation and the mechanical properties of the weld with a view to eliminate defects in joints of the Al-30Be-5Mg alloy welded by the electron-beam technique. Experiments have shown that the ratios of vapour components change as a function of the duration of electron-beam vacuum fusion of samples of the Al-3OBe-5Mg alloy. The increase in the time of existence of welding pool lowers the concentration of magnesium in the melt, and thus minimizes its adverse effect upon weld formation. This was achieved by using electron beam oscillations at frequencies of 50 to 100 Hz, and amplitudes of 3 to 4 mm in longitudinal and in longitudinal-transversal directions. It has been established that the introduction of a filler of an aluminium alloy containing not more than 3.5% Mg into the butt joint eliminates internal discontinuities in the form of pores or blue holes when the amount of the said filler in the weld is not less than 45%. Mechanical properties of welded joints are the best when the filler is the AK8 alloy

108

Lubricated wear resistance of Al-Cu-Mn-Mg-Si and Al-Si-Cu-Mn-Mg alloys against JIS ADC12 aluminium diecast alloy  

Energy Technology Data Exchange (ETDEWEB)

Aluminium alloys are light, easy to shape by plastic working, and in the case of casting alloys, can give better products and higher productivity by diecasting. Accordingly, the demand for mechanical components made from aluminium alloys has increased. In addition to strength, wear resistance is often required since moving aluminium components that make sliding contact with each other are becoming more common as machinery becomes lighter. For such applications the wear resistance of aluminium alloys is not generally sufficient unless greatly improved by the use of a lubricant. Thus, designs in which aluminium alloy components slide against one another can be used when the contact conditions are appropriate. (orig.)

Tanaka, T. [Junior Coll., Hikone, Shiga (Japan)

1995-03-01

109

On expediency of introducing the concept of strength equivalents of alloying elements in titanium alloys by aluminium and molybdenum  

International Nuclear Information System (INIS)

A term of strength equivalents of ?-stabilizers and neutral strengtheners by aluminium and ?-stabilizers by molybdenum is introduced. The equivalents are evaluated by the hardening action which alloying elements affect on ultimate tensile strength of commercial titanium alloys as compared to that of aluminium and molybdenum. Commercial and some prospecting pilot alloys produced in Russia, the USA, Great Britain, Germany, France and China are compared in coordinates of strengthening aluminium equivalent - strengthening molybdenum equivalent. The zones corresponding to different strength levels are shown in this diagram

110

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

Directory of Open Access Journals (Sweden)

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.

R. Singh

2011-12-01

111

Cold Spray Deposition of Titanium onto Aluminium Alloys  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in portuguese 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.

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

2010-06-01

112

Cold compression residual stress reduction in aluminium alloy 7010  

Energy Technology Data Exchange (ETDEWEB)

7010 is one of the high strength aluminium alloys used mainly as plate and forgings in the aerospace industry. Its high strength is achieved through a quenching operation where the material is rapidly cooled from the solution heat treatment temperature (475 C) to room temperature. As with all rapid quenching operations, residual stresses develop, leaving the material unsuitable for further machining operations and for service. Regular shaped forgings are generally cold compressed after quenching to relieve residual stresses. The effect of friction, increasing/decreasing the amount of cold compression and applying cold compression in 'bites' on residual stress magnitudes is unknown. This paper aims to study the effect that these variables have on final residual stress patterns through use of a finite element model. (orig.)

Tanner, D.A. [Limerick Univ. (Ireland). Materials Research Centre; Robinson, J.S. [Dept. of Materials Science and Technology, Univ. of Limerick (Ireland); Cudd, R.L. [HDA Forgings Ltd., Redditch, Worchestershire (United Kingdom)

2000-07-01

113

Electron irradiation of aluminium-zinc alloys. Pt. 3  

International Nuclear Information System (INIS)

An aluminium-4.5 at% zinc alloy was irradiated at temperatures between 25 and 1700C to doses of 7 dpa to 14 dpa at a dose rate of ? 3.88x10-3 dpa/s. Irradiation produced a very high density of coherent G.P. zones in the temperature range ? 80-? 1300C, coherent plate shaped precipitates in the temperature range ? 130-? 1600C and, under some irradiation conditions, large Zn precipitates on the foil surfaces. No precipitates occurred along the grain boundaries in the irradiated area. The matrix precipitation was interpreted in terms of the theory of Cauvin and Martin. The surface precipitation is ascribed to surface segregation of Zn and the non-appearance of precipitates along the grain boundaries in the irradiated area is thought to be due to the high metastability of the precipitates on the boundaries under irradiation. (orig.)

114

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.)

115

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

116

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

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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...

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

2007-01-01

117

Recovery of actinides from actinide-aluminium alloys by chlorination: Part II  

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A chlorination route is being investigated for recovery of actinides from actinide-aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl-KCl. In the present work, the most important steps of this route were experimentally tested using U-Pu-Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the sal...

Soucek, Pavel; Cassayre, Laurent; Eloirdi, Rachel; Malmbeck, Rikard; Meier, Roland; Nourry, Christophe; Claux, Benoit; Glatz, Jean-paul

2014-01-01

118

A review of friction stir welding of AA 6061 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

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

2011-01-01

119

The determination of sulphur in copper, nickel and aluminium alloys by proton activation analysis  

International Nuclear Information System (INIS)

The 34S(p, n)sup(34m)Cl reaction induced by 13-MeV protons is used for the determination of sulphur in copper, nickel and aluminium alloys. The sup(34m)Cl is separated by repeated precipitation as silver chloride. The results obtained were 3.08 +- 0.47, 1.47 +- 0.17 and -1 for copper, nickel and aluminium alloys, respectively. (Auth.)

120

The determination of sulphur in copper, nickel and aluminium alloys by proton activation analysis  

International Nuclear Information System (INIS)

The 34S(p,n)34sup(m)Cl reaction, induced by 13 MeV protons is used for the determination of sulphur in copper, nickel and aluminium alloys. The 34sup(m)Cl is separated by repeated precipitation as silver chloride. The results obtained were resp. 3.08 +- 0.47, 1.47 +- 0.17 and -1 for copper, nickel and aluminium alloys. (orig.)

 
 
 
 
121

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nkiko, Mojisola O.; Bamgbose, Janet T.

2011-01-01

122

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Czulak, A.; Konieczny, J.; Gude, M.; Dobrzan?ski, L. A.; Hufenbach, W.

2007-01-01

123

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

Science.gov (United States)

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.

Panagopoulos, C. N.; Georgiou, E. P.

2009-04-01

124

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.

125

Mackay icosahedron explaining orientation relationship of dispersoids in aluminium alloys.  

Science.gov (United States)

The orientation relations (ORs) of the cubic icosahedral quasicrystal approximant phase ?-Al(Fe,Mn)Si have been studied after low temperature annealing of a 3xxx wrought aluminium alloy by transmission electron microscopy. From diffraction studies it was verified that the most commonly observed OR for the ?-Al(Fe,Mn)Si dispersoids is [1\\bar 11]? // [1\\bar 11]Al, (5\\bar 2\\bar 7)? // (011)Al. This orientation could be explained by assuming that the internal Mackay icosahedron (MI) in the ?-phase has a fixed orientation in relation to Al, similar to that of the icosahedral quasi-crystals existing in this alloy system. It is shown that mirroring of the normal-to-high-symmetry icosahedral directions of the MI explains the alternative orientations, which are therefore likely to be caused by twinning of the fixed MI. Only one exception was found, which was related to the Bergman icosahedron internal to the T-phase of the Al-Mg-Zn system. PMID:25274523

Muggerud, Astrid Marie F; Li, Yanjun; Holmestad, Randi; Andersen, Sigmund J

2014-10-01

126

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)

127

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

128

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

International Nuclear Information System (INIS)

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

129

Straining mechanisms in aluminium alloy 6056. In-situ investigation by transmission electron microscopy  

International Nuclear Information System (INIS)

TEM in-situ straining tests, performed in precipitation hardened aluminium alloy 6056-T6, show that precipitates are sheared or by-passed by dislocations. By-passing, assisted by dislocation cross-slip, results in the formation and stress-induced spreading of non-planar loops. The relationship between those elementary mechanisms and the mechanical properties of the alloy is discussed

130

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 bor...

Nagli? I.; Smolej A.; Doberšek M.

2009-01-01

131

Mushy Zone Properties and Castability of Aluminium Foundry Alloys  

Energy Technology Data Exchange (ETDEWEB)

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.

Dahle, A.K.

1996-01-01

132

Ductility of aluminium alloy AA7075 at high strain rates  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2000-09-01

133

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

Directory of Open Access Journals (Sweden)

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.

A. Dolata-Grosz

2008-08-01

134

Effect of aluminium additions to zinc melt on corrosion resistance of iron base alloys  

International Nuclear Information System (INIS)

Effect of aluminium additions (3-8%) to zinc melt on corrosion resistance of iron-base alloys containing less than 0.1% C and also Si-, Mg-, S-, P impurities has been studied. It has been established experimentally that iron alloying with those elements increases its corrosion resistance in a zirc-aluminium melt in the following order: Cr, V, W, Si, Al, Mo, Ni. Unalloyed steel and also iron alloyed with Mg have low corrosion resistance. It has been shown that in zinc melt with 3-8% Al additions at 420-450 deg C possibilities of the oxide film formation on sample surface may arise mainly at the expense of alloying element. Obviously, as this takes place, a rate of the film formation exceeds a rate of the intermetallide iron-zinc and iron-aluminium layer formation. The formed oxide film prevents the development of interaction between a melt and a sample

135

Effect of heat treatment on small scale fragmentation of aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Small scale explosions, using a detonator, of 7075 aluminium alloy cylinders, 15-100 mm outside diameter, were carried out to investigate the effects of heat treatment on fragmentation. This was the finest for the strongest as received alloy and coarsest for the softest overaged alloy. This effect was similar to that seen in investigations of the fragmentation of steel. Cylinders of 50 and 100 mm in diameter did not fragment but plastically deformed with maximum deformation ...

Edwards, M. R.; Deal, C.

2011-01-01

136

The state of surface anode oxide films on aluminium and titanium alloys  

International Nuclear Information System (INIS)

Properties of the surface anode oxide films formed on aluminium and titanium alloys in the processes of electrochemical treatment in different composition solutions have been investigated using the contact difference of potentials and chronoamperometric methods. Effects of alloy components and dope of solution for anode treatment on the properties of anode oxide films have been studied. The technological features of oxidizing or electropolishing processes of the alloys investigated are presented

137

Corrosion behaviour of mechanically polished AA7075-T6 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present study, the effects of mechanical polishing on the microstructure and corrosion behaviour of AA7075 aluminium alloy are investigated. It was found that a nano-grained, near-surface deformed layer, up to 400 nm thickness, is developed due to significant surface shear stress during mechanically polishing. Within the near-surface deformed layer, the alloying elements have been redistributed and the microstructure of the alloy is modified; in particular, the normal MgZn2 particles f...

Liu, Yanwen; Laurino, Adrien; Hashimoto, Teruo; Zhou, Xiaorong; Skeldon, Peter; Thompson, George; Scamans, Geoff; Blanc, Christine; Rainforth, W. Mark; Frolish, Mike F.

2010-01-01

138

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

139

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

DEFF Research Database (Denmark)

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.

Din, Rameez Ud; Jellesen, Morten Stendahl

2014-01-01

140

BEHAVIOUR OF COPPER AND ALUMINIUM ELECTRODES ON EDM OF EN-8 ALLOY STEEL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrical discharge machining (EDM) has been recognized as an efficient production method for precision machining of electrically conducting hardened materials. Copper and aluminium are used as electrode materials in this process with Kerosene oil as the dielectric medium. In this work, the behavior of copper and aluminium electrodes on electric discharge machining of EN-8 alloy steel had been studied. Keeping all other machining parameters same, the hardened work material was machined with ...

DHANANJAY PRADHAN; Jayswal, Dr S. C.

2011-01-01

 
 
 
 
141

Process for the manufacture of plates containing neutron poison from aluminium and aluminium alloys  

International Nuclear Information System (INIS)

A process for guaranteeing sub-critical arrangements of nuclear fuel in tranport and/or storage containers is described, in which a homogeneous distribution of neutron poison in the aluminium matrix is guaranteed. A homogeneous mixture of aluminium powder and neutron poison powder is produced, this is pressed into plates in several stages, dried and made into hollow aluminium profiles of rectangular cross-section. The open ends of the hollow profile are then closed and this is rolled to the required dimension at 470-5000C. (orig./HP)

142

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

International Nuclear Information System (INIS)

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

143

Study of crack propagation behavior on low cycle fatigue in squeeze cast aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

In order to clarify the effect of eutectic silicon particles on low cycle fatigue, low cycle fatigue tests were carried out using squeeze cast aluminium alloy (JIS AC4CH) and anti-corrosion aluminium alloy (JIS A6061-T6). AC4CH and A6061-T6 are both aluminium alloys that mainly contain silicon and magnesium. The crack propagation behavior from the crack initiation to the fracture was investigated in detail by observing the surface of specimens and their fracture section. Our experiments have clarified that AC4CH has two kinds of crack growth rate depending on two different crack propagation routes. That is, AC4CH has the same crack growth rate as A6061-T6 if the crack is propagated on the matrix region. The crack growth rate in AC4CH is faster than that in A6061-T6 if the crack is propagated through the high density region of eutectic silicon particles. (orig.)

Morino, K.; Nishimura, F.; Takahashi, K. [Tokuyama Coll. of Technology, Yamaguchi (Japan). Dept. of Mechanical and Electrical Engineering; Kim, Y.H. [Dept. of Mechanical and Materials Engineering, Korea Maritime Univ., Pusan (Korea); Nisitani, H. [Dept. of Mechanical Engineering, Kyushu Sangyo Univ., Fukuoka (Japan)

2000-07-01

144

Stereometry specification and properties of anodization surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties, thickness and structure of an anodic layer formed on aluminium casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT, abrasive wear test was made with using ABR-8251 equipment delivered by TCD Teknologi ApS and microstructure investigations were made with using a light microscope equipped with an electronic camera configured with a computer on two casting aluminium alloys which both were founding by pressure die casting and gravity casting.Findings: The researches included analyze of the influence of chemical composition, geometry, roughness and abrasive wear resistant of anodic layer obtained on aluminium casts.Research limitations/implications: Contributes to research on anodic layer for aluminium casting alloys.Practical implications: Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminium casting alloys, e.g. in the range of raising resistance on corrosion.Originality/value: The range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.

L.A. Dobrza?ski

2008-09-01

145

Aluminium alloys welding with high-power Nd:YAG lasers  

International Nuclear Information System (INIS)

Aluminium alloys have good mechanical properties (high strength-to-weight ratio, corrosion resistance) and good workability. their applications are growing up, specially in the transportation industry. Weldability is however poorer than in other materials; recent advances in high power YAG laser are the key to obtain good appearance welds and higher penetration, at industrial production rates. Results of the combination of high power YAG beams with small fiber diameters and specific filler wires are presented. It is also characterized the air bone particulate material, by-product of the laser process: emission rates, size distribution and chemical composition are given for several aluminium alloys. (Author) 6 refs

146

Kinetics of oxidation of liquid aluminium alloys with zink and cadmium  

International Nuclear Information System (INIS)

The kinetics of oxidation of liquid alloys was studied by means of thermogravimetric method based on continuous weighting of melted metal. The oxidation of pure aluminium was carried out at temperature ranges 1003, 1053, and 1103 K. All aluminium-zinc alloys were oxidated at temperature ranges 973, 1023, and 1073. It was found that at increasing of zink concentration till 7,5% the rate of oxidation decreases and the activation energy increases. But at increasing of zinc concentration till 10% the oxidation rate increases.

147

Enrichment factors for copper in aluminium alloys following chemical and electrochemical surface treatments  

International Nuclear Information System (INIS)

Surface treatments, including chemical polishing, alkaline etching, acid pickling, and electropolishing, of aluminium and copper-containing aluminium alloys lead to enrichment of solid solution copper in the metal just beneath the residual oxide films of the treatment processes. The paper presents the enrichment factor for copper as a function of the copper content of the bulk matrix material. The factor is defined as the ratio of the copper enrichment, measured in units of 1015 atoms cm-2, to the copper content of the matrix in at.%. Although absolute levels of enrichment increase with increase in copper content of the alloy, the enrichment factor increases in the opposite sense

148

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

Directory of Open Access Journals (Sweden)

Full Text Available Electron backscattered diffraction investigations on just fully recrystallised orientation image microstructures, showed that the cube-oriented grains had the largest size in all microstructures of an aluminium alloy, which have potential use in the cartridge case manufacturing for defence purpose. The simulation of cube microstructure and texture of that aluminium alloy was tried. The recrystallisation texture and microstructure simulation by the 3-D cellular automaton model with the consideration of highest mobility of 40º grainboundary, predicted the volume fraction of the cube texture orientation which was validated by experiment.

Prantik Mukhopadhyay

2010-05-01

149

Stress-strain relations for aluminium alloys experimental verification of the Ramberg-Osgood law  

International Nuclear Information System (INIS)

Stress-strain relations are significant when an analysis in elastic-plastic and plastic range of certain material is carried out. Moreover, in nonlinear numerical analysis is necessary to obtain mathematical formulation of these curves. In this paper is presented the way for obtaining a mathematical model of stress-strain curves for the aluminium alloy AlMgSi0.5, using the Ramberg-Osgood law and through the compression test of specimens. Finally, with comparison of the experimental and the theoretical results it is confirmed that the Ramberg-Osgood law satisfactory describe the stress-strain relations for certain aluminium alloy. (Author)

150

Predicting the thermal conductivity of aluminium alloys in the cryogenic to room temperature range  

Science.gov (United States)

Aluminium alloys are being used increasingly in cryogenic systems. However, cryogenic thermal conductivity measurements have been made on only a few of the many types in general use. This paper describes a method of predicting the thermal conductivity of any aluminium alloy between the superconducting transition temperature (approximately 1 K) and room temperature, based on a measurement of the thermal conductivity or electrical resistivity at a single temperature. Where predictions are based on low temperature measurements (approximately 4 K and below), the accuracy is generally better than 10%. Useful predictions can also be made from room temperature measurements for most alloys, but with reduced accuracy. This method permits aluminium alloys to be used in situations where the thermal conductivity is important without having to make (or find) direct measurements over the entire temperature range of interest. There is therefore greater scope to choose alloys based on mechanical properties and availability, rather than on whether cryogenic thermal conductivity measurements have been made. Recommended thermal conductivity values are presented for aluminium 6082 (based on a new measurement), and for 1000 series, and types 2014, 2024, 2219, 3003, 5052, 5083, 5086, 5154, 6061, 6063, 6082, 7039 and 7075 (based on low temperature measurements in the literature).

Woodcraft, Adam L.

2005-06-01

151

Analysis of intermetallic particles in AlSi1MgMn aluminium alloy  

Directory of Open Access Journals (Sweden)

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

G. Mrówka-Nowotnik

2007-01-01

152

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)

153

Recovery of actinides from actinide-aluminium alloys by chlorination: Part II  

Science.gov (United States)

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

Sou?ek, P.; Cassayre, L.; Eloirdi, R.; Malmbeck, R.; Meier, R.; Nourry, C.; Claux, B.; Glatz, J.-P.

2014-04-01

154

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

International Nuclear Information System (INIS)

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

155

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

International Nuclear Information System (INIS)

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

156

Evaluation Of Four Welding Arc Processes Applied To 6061 Aluminium Alloy  

Science.gov (United States)

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

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

2011-01-01

157

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

DEFF Research Database (Denmark)

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.

Ambat, Rajan

2007-01-01

158

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.)

159

THE METALLURGICAL ASPECTS OF ALUMINIUM-LITHIUM ALLOYS IN VARIOUS PRODUCT FORMS FOR HELICOPTER STRUCTURAL APPLICATIONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The reduced density and concommitant increased elastic modulus of aluminium-lithium based alloys have created intense interest throughout the aerospace industry and associated organisations since the beginning of the present decade. Many Companies and Establishments have evaluated the new alloys to have emerged with a view to potential incorporation into their specific products and this paper describes the results from a number of such metallurgical examinations undertaken at WESTLAND HELICOP...

Smith, A.

1987-01-01

160

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Laukli, Hans Ivar

2004-01-01

 
 
 
 
161

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form o...

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

2012-01-01

162

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Dolata-grosz, A.; Dyzia, M.; S?leziona, J.

2008-01-01

163

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

Directory of Open Access Journals (Sweden)

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.

J. Horsinka

2011-04-01

164

Study of localized corrosion in AA2024 aluminium alloy using electron tomography  

International Nuclear Information System (INIS)

Highlights: ? SEM tomography of localized corrosion has been achieved. ? Nanotomography provides evidence that links microstructure and corrosion propagation path. ? IGC stemmed from localized corrosion associated with buried clusters of intermetallics. ? IGC started beneath the alloy surface and may emerge on the alloy surface. - Abstract: SEM based tomography of localized corrosion has been achieved using selective detection of backscattered electrons. The high resolution tomography provides direct evidence that links the surface appearance of corroded alloy, the alloy microstructure and the corrosion propagation path. Stable localized corrosion of AA2024-T351 aluminium alloy was initiated at locations where large clusters of S phase particles were buried beneath the surface. Propagating away from the initiation sites, corrosion developed preferentially along the grain boundary network. The grain boundary attack started beneath the alloy surface, proceeded along preferred grain boundaries and may emerge at the alloy surface.

165

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.

166

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

167

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

168

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

Directory of Open Access Journals (Sweden)

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 the 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.

Kátia Regina Cardoso

2007-06-01

169

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2007-06-01

170

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

Directory of Open Access Journals (Sweden)

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.

A. Zyska

2011-07-01

171

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

172

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

Science.gov (United States)

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®) 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.

Torres, E.; Ugues, D.; Brytan, Z.; Perucca, M.

2009-05-01

173

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.

174

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

Science.gov (United States)

This study explores a combined pyro-hydrometallurgical method to recover pure aluminium, nickel-copper alloy(s), and some valuable salts from spent fluorescent lamps (SFLs). It also examines the safe recycling of clean glass tubes for the fluorescent lamp industry. Spent lamps were decapped under water containing 35% acetone to achieve safe capture of mercury vapour. Cleaned glass tubes, if broken, were cut using a rotating diamond disc to a standard shorter length. Aluminium and copper-nickel alloys in the separated metallic parts were recovered using suitable flux to decrease metal losses going to slag. Operation variables affecting the quality of the products and the extent of recovery with the suggested method were investigated. Results revealed that total loss in the glass tube recycling operation was 2% of the SFLs. Pure aluminium meeting standard specification DIN 1712 was recovered by melting at 800 degrees C under sodium chloride/carbon flux for 20 min. Standard nickel-copper alloys with less than 0.1% tin were prepared by melting at 1250 degrees C using a sodium borate/carbon flux. De-tinning of the molten nickel-copper alloy was carried out using oxygen gas. Tin in the slag as oxide was recovered by reduction using carbon or hydrogen gas at 650-700 degrees C. Different valuable chloride salts were also obtained in good quality. Further research is recommended on the thermodynamics of nickel-copper recovery, yttrium and europium recovery, and process economics. PMID:14761750

Rabah, Mahmoud A

2004-01-01

175

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

176

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

Directory of Open Access Journals (Sweden)

Full Text Available Warm forming of metal materials represents a profitable method of precise forming pieces production due to energy and time savings, obtaining of higher surface quality and dimension precision of forming pieces in comparison with hot forming. An optimal forming temperature was selected from experimental measurement of mechanical properties, plasticity and workability of an aluminium alloy. Upsetting forming process of aluminium alloy AlSiMg type was simulated using finite element method at warm forming temperatures. Numerical simulation of the alloy forming based on finite elements methods was verified, the results of the numerical simulation were compared with experimental result - degree of grain boundaries deformation obtained by stereological metallography. From the results an optimal temperature of warm forming was estimated.

Maros Martinkovic

2012-05-01

177

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

Directory of Open Access Journals (Sweden)

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.

Nagli? I.

2009-07-01

178

The effect of different shot peening intensities on fatigue life of AW 7075 aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available In this study the effect of different shot peening intensities, from very light peening with ceramic beads to severe shot peening with high coverage, on the fatigue life of aircraft AW 7075 aluminium alloy was investigated. Results were discussed in means of surface roughness, character of deformed surface layer and residual stress profile measured by XRD methods. Light peening intensity creates high and shallow compression residual stress field in the subsurface layers of material and increases the fatigue life of studied alloy. Increasing the peening intensity increases the depth of residual stress field, however the surface damage created by impact of shots at high velocity causes significant surface damage and rapidly degrade the fatigue properties of AW 7075 aluminium alloy.

Libor Trško

2013-12-01

179

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

DEFF Research Database (Denmark)

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.

Aggerbeck, Martin; Canulescu, Stela

2014-01-01

180

Characterisation of early precipitation stages in 6xxx series aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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.

Hasting, Haakon S [Norwegian University of Science and Technology NTNU, Department of Physics, Hogskoleringen 5, N-7491 Trondheim (Norway); Walmsley, John [Norwegian University of Science and Technology NTNU, Department of Physics, Hogskoleringen 5, N-7491 Trondheim (Norway); Marioara, Calin D [SINTEF Materials and Chemistry, 7465 Trondheim (Norway); Helvoort, ATJ van [Norwegian University of Science and Technology NTNU, Department of Physics, Hogskoleringen 5, N-7491 Trondheim (Norway); Holmestad, Randi [Norwegian University of Science and Technology NTNU, Department of Physics, Hogskoleringen 5, N-7491 Trondheim (Norway); Danoix, Frederic [CNRS, Groupe de Physique des Materiaux, 76801 Saint Etienne du Rouvray Cedex (France); Lefebvre, Williams [CNRS, Groupe de Physique des Materiaux, 76801 Saint Etienne du Rouvray Cedex (France)

2006-02-22

 
 
 
 
181

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

182

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

International Nuclear Information System (INIS)

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

183

Investigation into the strength of components made of UFG aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

184

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

He?naff, Gilbert; Menan, Fre?de?ric; Odemer, Gre?gory

2010-01-01

185

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Anjo, Victor; Khan, Reyaz

2013-01-01

186

Application of artificial neural networks for modelling correlations in age hardenable aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This paper discusses some of the preliminary results of an ongoing research on the applications of artificial neural networks (ANNs in modelling, predicting and simulating correlations between mechanical properties of age hardenable aluminium alloys as a function of alloy composition.Design/methodology/approach: Appropriate combinations of inputs and outputs were selected for neural network modelling. Multilayer feedforward networks were created and trained using datasets from public literature. Influences of alloying elements, alloy composition and processing parameters on mechanical properties of aluminium alloys were predicted and simulated using ANNs models.Two sample t-tests were used to analyze the prediction accuracy of the trained ANNs.Findings: Good performances of the neural network models were achieved. The models were able to predict mechanical properties within acceptable margins of error and were able to provide relevant simulated data for correlating alloy composition and processing parameters with mechanical properties. Therefore, ANNs models are convenient and powerful tools that can provide useful information which can be used to identify desired properties in new aluminium alloys for practical applications in new and/or improved aluminium products.Research limitations/implications: Few public data bases are available for modelling properties. Minor contradictions on the experimental values of properties and alloy compositions were also observed. Future work will include further development of simulated data into property charts.Practical implications: Correlations between mechanical properties and alloy compositions can help in identifying a suitable alloy for a new or improved aluminum product application. In addition, availability of simulated structure-process-property data or charts assists in reducing the time and costs of trial and error experimental approaches by providing near-optimal values that can be used as starting point in experimental work.Originality/value: Since the simulated data provides near-optimal values, manufacturers of new and/or improved aluminum alloys can use the simulated data as guidelines for narrowing down extensive experimental work. This in turn reduces the process design cycle times. Designers of new and/or improved aluminum products can also use the simulated data as a guideline for correlating property-application information, which is useful in preliminary design phase.

F. Musharavati

2010-07-01

187

Effect of aluminium and niobium on the magnetic properties and structure of Fe-Cr-Co alloy monocrystals  

International Nuclear Information System (INIS)

Effect of aluminium and niobium alloying on magnetic properties and structure of monocrystals of Fe-Cr-Co alloys with 18% Co is studied. Dependence of magnetic properties on crystallographical direction of the field and thermomagnetic treatment are considered. It is shown that at separate and combined alloying with aluminium and niobium in studied quantities the thermomagnetic treatment effect in alloys remains to be isotropic, i.e. the level of magnetic properties does not depend on crystallographic direction of the field of thermomagnetic treatment. Aluminium is concentrated mainly in ?1-phase, probably it is concerned to niobium. In all studied alloys the difference of lattice parameters of ?1 and ?2 phases is less than in ternary Fe-Cr-Co alloys

188

Magnesium die casting alloys for use in applications exposed to elevated temperatures: can they compete with aluminium?  

Energy Technology Data Exchange (ETDEWEB)

Ever since the development of the VW-Beetle engine and transmission, magnesium die cast parts have been seen as candidates for automotive drive train components. It was early recognised that the temperature exposure of the crankcase was challenging the mechanical properties of the commonly used alloy AZ81. This led to developments of alloys of the type AS41 and AS21, and even AS11 was tested. These alloys showed creep properties compatible with the increasing demands from the engine developers [1]. Automotive designers, used to design in aluminium, may have a tendency to see magnesium as a light version of aluminium. This is often supported by the sometimes overoptimistic attitudes of new entrants in the magnesium industry, strongly promoting proprietary alloy compositions. The present paper provides an overview of current magnesium die cast alloy candidates for elevated temperature applications. Properties are discussed relative to defined requirements, and compared with those of currently used aluminium die casting alloys. (orig.)

Westengen, H.; Bakke, P. [Norsk Hydro ASA, Porsgrunn (Norway)

2003-07-01

189

Surface modification of aluminium alloys using hybrid treatment techniques  

Science.gov (United States)

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.

Petrov, P.

2012-03-01

190

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.

191

Modelling research of hydrogen desorption from liquid aluminium and its alloys  

Directory of Open Access Journals (Sweden)

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.

M. Saternus

2011-10-01

192

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

Energy Technology Data Exchange (ETDEWEB)

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.

Ghaini, F. Malek, E-mail: fmalek@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, Jalal-e-Aleahmad, Tehran (Iran, Islamic Republic of); Sheikhi, M., E-mail: Sheikhi.mohsen@yahoo.com [Department of Materials Engineering, Tarbiat Modares University, Jalal-e-Aleahmad, Tehran (Iran, Islamic Republic of); Torkamany, M.J., E-mail: mjtorkamany@yahoo.com [Laser Science and Technology National Lab. (LSTNL), P.O. Box: Tehran 14665-576 (Iran, Islamic Republic of); Sabbaghzadeh, J. [Laser Science and Technology National Lab. (LSTNL), P.O. Box: Tehran 14665-576 (Iran, Islamic Republic of)

2009-08-30

193

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.

194

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

International Nuclear Information System (INIS)

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

195

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

196

Shear Strength Response of the Aluminium Alloy 6082-T6 During One-Dimensional Shock Loading  

Science.gov (United States)

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

Harrigan, John; Millett, Jeremy; Bourne, Neil

2007-06-01

197

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

International Nuclear Information System (INIS)

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

198

Influence of the composition and heat treatments in the mechanical properties of aluminium bronze alloys  

International Nuclear Information System (INIS)

Aluminium bronzes are copper-base alloys containing aluminium within the limits between 5-12%. Additions of Fe, Ni and Mn are used as alloying elements forming a family of complex alloys noted for their exceptional strength and corrosion resistance. In present paper sd the Ni:Fe ratio and heat treatments have been analyzed by determining the mechanical properties for three different aluminium bronze alloys containing Cu-Al10-Fe3, Cu-Al10-Fe5-Ni5 and Cu-Al10-Fe4-Ni8. The effect of as cast, quenched and quenched and tempered structures has been investigated regarding hardness, proof and ultimate tensile strength, elongation, modules of elasticity, Poisson ratio, fracture toughness, fatigue strength, crack propagation and Charpy impact properties. The influence of temperature has been studied by testing the elastic modules, Poisson ratio, the proof stress, tensile strength and the Charpy impact properties at -20 degree centigree, 24 degree centigree and 100 degree centigree. (Author)

199

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

Science.gov (United States)

In this work we show that nanocrystalline iron and iron-aluminium alloys can be electrodeposited from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py1,4]TfO, at 100 °C. The study comprises CV, SEM, XRD, and magnetic measurements. Two different sources of iron(ii) species, Fe(TfO)2 and FeCl2, were used for the electrodeposition of iron in [Py1,4]TfO. Cyclic voltammetry was employed to evaluate the electrochemical behavior of FeCl2, Fe(TfO)2, and (FeCl2 + AlCl3) in the employed ionic liquid. Thick iron deposits were obtained from FeCl2/[Py1,4]TfO at 100 °C. Electrodeposition of iron-aluminium alloys was successful in the same ionic liquid at 100 °C. The morphology and crystallinity of the obtained deposits were investigated using SEM and XRD, respectively. XRD measurements reveal the formation of iron-aluminium alloys. First magnetic measurements of some deposits gave relatively high coercive forces and power losses in comparison to commercial iron-silicon samples due to the small grain size in the nanometer regime. The present study shows the feasibility of preparing magnetic alloys from ionic liquids. PMID:24715034

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

2014-05-28

200

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

Directory of Open Access Journals (Sweden)

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.

Benoit Alexandre

2013-11-01

 
 
 
 
201

Mechanical properties of aluminium-uranium alloy and aluminium commercially pure at several temperatures  

International Nuclear Information System (INIS)

The mechanical properties of Ai-U (18,4 wt %) alloy with and without heat treatment were determined, and they were compared with the mechanical properties of aluminum alloy of commercial purity, AI-1100, at tempiratures of 25, 500, 550 and 6000C, the changes of both the yield point stress and the ultimate tensile strength as a function of temperature may be described through two emperical relationships. A fractography study was also made

202

Iron aluminium alloys with strengthening carbides and intermetallic phases for high-temperature applications  

Energy Technology Data Exchange (ETDEWEB)

An overview of materials developments of iron aluminium alloys with strengthening precipitate phases is given. The discussion is focussed on recent studies on Fe-Al-based alloys with strengthening precipitates, such as {kappa}-phase Fe{sub 3}AlC{sub x}, MC-carbide and Laves phase. Alloys of the following alloy systems were investigated: Fe-Al-C, Fe-Al-Ta, Fe-Al-Ni, Fe-Al-Ti-Nb, and Fe-Al-M-C (M = Ti, V, Nb, Ta). The investigations were centred on microstructure, constitution, and mechanical properties of such Fe-Al-based alloys with Al contents ranging from 10 to 30 at.%. Mechanisms and problems are discussed and perspectives are outlined. (orig.)

Schneider, A.; Sauthoff, G. [Max-Planck-Inst. fuer Eisenforschung, Duesseldorf (Germany)

2004-01-01

203

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

DEFF Research Database (Denmark)

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.

Din, Rameez Ud; Jellesen, Morten Stendahl

204

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

205

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

Science.gov (United States)

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

Draissia, Mohamed; Debili, Mohamed-Yacine

2005-09-01

206

Friction welding of ultrahigh vacuum transition between aluminium alloy and stainless steel  

International Nuclear Information System (INIS)

Friction welding has been developed at KEK to join aluminium alloy vacuum chambers to stainless steel vacuum components of an electron storage ring. The stainless steel surface is electroplated with silver to a thickness of 10 ?m before welding. Additional procedures such as complicated pre-treatment for electroplating, various heat treatment and various cleaning procedures are not required. Fabricated transitions up to 100 mm in diameter have been obtained. Some units have been tested for mechanical and vacuum leak properties as beam ducts. It has been found that the strength of the bonding plane is very strong and fracture of the tensile specimens occurs not at the bonded plane but at the aluminium alloy part, and that vacuum leak does not occur for heat cycles up to 2000C. Welds torerate thermal shock to liquid nitrogen temperature and remain leak-tight. (author)

207

On the mechanism of creep in short fibre reinforced aluminium alloys  

International Nuclear Information System (INIS)

The present work studies creep damage accumulation in a squeeze cast, short fibre reinforced aluminium alloy containing 15 vol.% of Saffil fibres. Fibre breakage occurs early in creep life. Individual fibres can undergo more than one rupture event. Primary and tertiary creep are closely related processes and cannot be considered as being independent. The minimum creep rate is a result of a superposition of load transfer from the matrix to the fibres (decrease of creep rate) and fibre breakage (increase of creep rate). In summary, creep of short fibre reinforced aluminium alloys is governed by three elementary processes including (i) loading of fibres through the formation of a work hardened zone around the fibres, (ii) a recovery mechanism in the work hardened zone, and (iii) the breakage of fibres into subfibres. (orig.)

208

Fatigue damage rule of LY12CZ aluminium alloy under sequential biaxial loading  

Science.gov (United States)

A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ aluminium alloy. The loading paths of 90° out-of-phase, 45° out-of-phase and 45° in-phase are utilized. The fatigue damage cumulative rules under two-level step loading of three loading paths are analyzed. By introducing a parameter ? which is a function of the phase lag angle between the axial and the torsional loading, a new multiaxial nonlinear fatigue damage cumulative model is proposed. The proposed model is evaluated by the experimental data for two-level loading, multi-level loading of LY12CZ aluminium alloy, and multi-level loading of 45 steel. Fatigue lives predicted are within a factor of 2 scatter band.

Wang, YingYu; Zhang, DaChuan; Yao, WeiXing

2014-01-01

209

Friction and wear behavior of surface nanocrystallized aluminium alloy under dry sliding condition  

Energy Technology Data Exchange (ETDEWEB)

One way of improving the surface properties of engineering material is by reducing the grain size at the surface. Controlled ball impact process is developed for producing surface nanocrystallization and improves the surface mechanical properties by inducing compressive residual stress on the metallic materials. Improvement in the surface mechanical properties will affect the tribological properties. This paper reports the influence of the surface nanocrystallization on the tribological properties of aluminium alloy. Tribological properties were evaluated under dry sliding conditions using a reciprocating wear test facility. The friction coefficient of the treated surface is lower than that of the untreated samples and treatment improves the wear resistance of aluminium alloys. The improvement in the friction and wear properties is due to enhancement of surface strength, due to grain refinement and induction of compressive residual stress. The worn surfaces observed using scanning electron microscope reveal the dominant adhesive nature of wear and mild abrasive wear.

Prakash, N. Arun [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Gnanamoorthy, R., E-mail: gmoorthy@iitm.ac.i [Indian Institute of Information Technology, Design and Manufacturing (IIITD and M) Kancheepuram, Chennai 600036 (India); Kamaraj, M. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)

2010-04-15

210

Composite Ni-Co-fly ash coatings on 5083 aluminium alloy  

International Nuclear Information System (INIS)

Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite 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-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

211

Composite Ni-Co-fly ash coatings on 5083 aluminium alloy  

Science.gov (United States)

Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite 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-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

Panagopoulos, C. N.; Georgiou, E. P.; Tsopani, A.; Piperi, L.

2011-03-01

212

Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys  

Directory of Open Access Journals (Sweden)

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.

E. Matykina

2010-01-01

213

Weld metal grain refinement of aluminium alloy 5083 through controlled additions of Ti and B  

Energy Technology Data Exchange (ETDEWEB)

The refinement of the weld metal grain structure may lead to a significant change in its mechanical properties and in the weldability of the base metal. One possibility to achieve weld metal grain refinement is the inoculation of the weld pool. In this study, it is shown how additions of titanium and boron influence the weld metal grain structure of GTA welds of the aluminium alloy 5083 (Al Mg4.5Mn0.7). For this purpose, inserts consisting of base metal and additions of the master alloy Al Ti5B1 have been cast, deposited in the base metal and fused in a GTA welding process. The increase of the Ti and B content led to a significant decrease of the weld metal mean grain size and to a change in grain shape. The results provide a basis for a more precise definition of the chemical composition of commercial filler wires and rods for aluminium arc welding. (orig.)

Schempp, Philipp; Rethmeier, Michael [Federal Institute for Materials Research and Testing BAM, Berlin (Germany). Div. ' ' Safety of Joined Components' ' ; Fraunhofer Institute for Production Systems and Design Technology IPK, Berlin (Germany). Dept. ' ' Joining and Coating Technology' ' ; Schwenk, Christopher; Cross, Carl Edward [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

2011-07-01

214

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

Science.gov (United States)

Cold spraying is increasingly being used for reconstruction or repair of damaged aluminium alloy components, especially in the aviation industry. Both thin (mechanical properties of the coating. In this study, two sets (single- and multi-pass) of aluminium alloy (AA6061) coatings with different thicknesses (0.5 mm to 2 mm) were deposited onto AA6061 substrates and compared using metallographic and fractographic analyses, four-point bending testing, residual stress analysis and Vickers microhardness indentation. Finally, the coating adhesion and cohesion were measured using the standard ASTM-C633 adhesion test and tubular coating tensile test. This study demonstrates that the single-layer strategy results in greater adhesion and lower porosity, while multilayer coatings have higher elastic modulus. Independent of the strategy, the compressive residual stress decreases as a function of coating thickness.

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

2014-08-01

215

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

Directory of Open Access Journals (Sweden)

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.

Mojisola O. Nkiko

2011-11-01

216

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: English Abstract in english 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.

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

2011-11-01

217

Laser surface treatment of magnesium alloys with aluminium oxide powder  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of this paper was to improve the magnesium cast alloys surface layer by laser surface treatment and to determine the laser treatment parameters.Design/methodology/approach: The laser treatment of magnesium alloys with alloying Al2O3 powder of the particle about 80?m was carried out using a high power diode laser (HPDL. The resulting microstructure in the modified surface layer was examined using scanning electron microscopy. Phase composition was determined by the X-ray diffraction method using the XPert device. The measurements of microhardness of the modified surface layer were also studied.Findings: The alloyed region has a fine microstructure with hard carbide particles. Microhardness of laser surface alloyed layer was significantly improved as compared to an alloy without laser treatment.Research limitations/implications: The investigations were conducted for cast magnesium alloys MCMgAl12Zn1, MCMgAl9Zn1, MCMgAl6Zn1, MCMgAl3Zn1 and Al2O3 powder of the particle size about 80 ?m. One has used laser power in the range from 1.2to 2.0 kW.Practical implications: The results obtained in this investigation were promising comparing with the other conventional processes. High Power Diode Laser can be used as an economical substitute of Nd: YAG and CO2 to improve the surface magnesium alloy by feeding the carbide particles.Originality/value: The value of this paper is to define the influence of laser treatment parameters on quality, microstructure and microhardness of magnesium cast alloys surface layer.

L.A. Dobrza?ski

2009-11-01

218

Age hardening of the aluminium alloy EN 4017  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

219

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Tanner, D. A.

1999-01-01

220

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2003-01-01

 
 
 
 
221

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

International Nuclear Information System (INIS)

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

222

Spray formed and rolled aluminium-magnesium-scandium alloys with high scandium content  

Energy Technology Data Exchange (ETDEWEB)

Aluminium-magnesium-scandium alloys offer good weldability, high corrosion resistance, high thermal stability and the potential for high strength by precipitation hardening. A problem of aluminium-scandium alloys is the low solubility of about 0.3 mass-% scandium when using conventional casting methods. The solution of scandium can be raised by higher cooling rates during solidification. This was realised by spray forming of Al-4.5Mg-0.7Sc alloys as flat deposits. Further cooling rates after solidification should also be high to prevent coarse precipitation of secondary Al{sub 3}Sc. Therefore a cooling device was designed for the spray formed flat deposits. The flat deposits were rolled at elevated temperatures to close the porosity from spray forming. Microstructures, aging behaviour and tensile properties of the rolled sheets were investigated. Strength enhancements of about 100 MPa compared to conventional Al-Mg-Sc alloys were achieved. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [German] Aluminium-Magnesium-Scandium-Legierungen zeichnen sich durch gute Schweisseignung, hohe Korrosionsbestaendigkeit, hohe thermische Stabilitaet und ein hohes Potenzial zur Ausscheidungshaertung aus. Problematisch ist die relativ geringe Loeslichkeit von 0,3 Masse-% Scandium in Aluminium bei konventionellen Giessverfahren. Die Loeslichkeit von Scandium kann durch hoehere Abkuehlgeschwindigkeiten bei der Erstarrung gesteigert werden. Dies wurde mittels Spruehkompaktieren einer AlMg4,5Sc0,7-Legierung zu Flachprodukten realisiert. Auch nach der Erstarrung muss die Abkuehlgeschwindigkeit ausreichend hoch sein, um grobe sekundaere Al{sub 3}Sc-Ausscheidungen zu unterdruecken. Dies wurde mittels einer Kuehlvorrichtung fuer die spruehkompaktierten Flachprodukte realisiert. Anschliessend wurden die Flachprodukte warmgewalzt, um die Porositaet zu schliessen. Gefuege, Auslagerungsverhalten und Kenngroessen des Zugversuchs der gewalzten Bleche wurden untersucht. Die Festigkeit konnte um ca. 100 MPa gegenueber konventionellen Al-Mg-Sc-Legierungen gesteigert werden. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Herding, T. [Aleris Aluminum Bitterfeld GmbH, Devillestrasse 2, 06749 Bitterfeld (Germany); Kessler, O. [University of Rostock, Faculty of Mechanical Engineering and Marine Technology, Chair of Materials Science, Rostock (Germany); Zoch, H.W. [Stiftung Institut fuer Werkstofftechnik, Badgasteiner Strasse 3, 28359 Bremen (Germany)

2007-10-15

223

Coatings Produced in Aluminium Bath on High-Carbon Alloys with Additions of Chromium and Nickel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study the problem of coatings produced in liquid aluminium on high-carbon Fe-C-Cr and Fe-C-Ni alloys has been discussed. Aluminising has been carried out at temperatures of 710oC and 745oC during the time of 30 to 900 seconds. The morphology of thus produced coatings has been examined along with the chemical composition and phase constitution of individual layers. Microhardness measurements have been taken.

Lepka, E.; Rzadkosz, S.

2007-01-01

224

Coatings Produced in Aluminium Bath on High-Carbon Alloys with Additions of Chromium and Nickel  

Directory of Open Access Journals (Sweden)

Full Text Available In this study the problem of coatings produced in liquid aluminium on high-carbon Fe-C-Cr and Fe-C-Ni alloys has been discussed. Aluminising has been carried out at temperatures of 710oC and 745oC during the time of 30 to 900 seconds. The morphology of thus produced coatings has been examined along with the chemical composition and phase constitution of individual layers. Microhardness measurements have been taken.

E. Lepka

2007-07-01

225

Microstructure control and extrudability of aluminium-Mg-Si alloys microalloyed with manganese  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The hot deformation behaviour of AA 6063 and AA 6005 aluminium alloys has been related to chemical composition and the microstructural evolution occurring during the various heat treatment procedures prior to extrusion. It was shown that a small addition of manganese significantly accelerates the homogenising process (transformation of the plate-like beta-AlFeSi phase to the more rounded alpha-AlFeSi phase) which gives better hot formability and ductility. The mechanical behaviour of Al-Mg-Si...

Zajac, S.; Hutchinson, B.; Johansson, A.; Gullman, L. -o; Lagneborg, R.

1993-01-01

226

Residual stress development and relief in high strength aluminium alloys using standard and retrogression thermal treatments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Residual stresses develop in the aluminium alloy 7010 when the material is quenched from the solution heat treatment temperature. Residual stress measurements have been made using the X-ray diffraction technique and a longitudinal split sawcut method to determine the magnitude of residual stress that develops in specimens sectioned from large open die forgings as a result of (a) quenching these specimens into water at different temperatures, and (b) cold water quenching from different furnace...

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

2003-01-01

227

RETROGRESSION AND RE-AGING TREATMENT OF AA 7049 ALUMINIUM ALLOY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of retrogression and re-aging (RRA) on the strength and corrosion performance was evaluated for AA 7049 aluminium alloy. Samples from extruded profiles were treated to T6 and T73 temper. Also Retrogression was performed at four different temperatures between 1800C – 2400C for various times followed by re-aging at1200C. The properties like ultimate tensile strength (UTS), hardness and conductivity measurement,intergrannular corrosion and exfoliation studies are presented. The resu...

Ranganatha, R.; Raghothama Rao, Dr P.; Bhat, Dr R. R.; Muralidhara, Dr B. K.

2011-01-01

228

Analysis of FSW welds made of aluminium alloy AW6082-T6  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: of this paper is to analyze the results of tests on the mechanical properties and microstructural changes in Friction Stir Welds in the aluminium alloy 6082-T6 in function of varying process parameters.Design/methodology/approach: : the produced tensile strength of the produced welds was measured and the correlation with process parameter was assessed. The welds’ microstructure in various zones was analyzed using an optical microscope. Microhardness measurements were performed on t...

Szkodo, M.; Ponte, M.; Lertora, E.; Gambaro, C.; Adamowski, J.

2007-01-01

229

Deformation structures in 6082 aluminium alloy after severe plastic deformation by equal-channel angular pressing  

International Nuclear Information System (INIS)

Deformation structures of a commercial Al-Mg-Si alloy (6082) processed by equal-channel angular pressing at room temperature were characterized by transmission electron microscopy. Deformation twins, which have never been observed in coarse-grained aluminium, were experimentally confirmed together with numerous other features. The possible roles of twinning and different grain boundary structures on the severe plastic deformation (SPD) mechanisms, including grain refinement, were discussed

230

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 reinforcem...

Fatchurrohman, N.; Sulaiman, S.; Ariffin, M. K. A.; Baharuddin, B. T. H. T.; Faieza, A. A.

2012-01-01

231

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1993-01-01

232

Taguchi Optimization of Process Parameters on the Hardness and Impact Energy of Aluminium Alloy Sand Castings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An optimization technique for sand casting process parameters based on the Taguchi method is reported in this paper. While keeping other casting parameters constant, aluminium alloy castings were prepared by sand casting technique using three different parameters, namely the mould temperature, pouring temperature and runner size. Hardness and impact energy tests were done for the resulted castings. The settings of parameters were determined by using the Taguchi experimental design method. The...

Oji, John O.; Sunday, Pamtoks H.; Petinrin, Omolayo M.; Adetunji, Adelana R.

2013-01-01

233

Stereometry specification and properties of anodization surface of casting aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties, thickness and structure of an anodic layer formed on aluminium casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT, abrasive wear test was made with using ABR-8251 equipment delivered by TCD Teknologi ApS and microstructure investigations were made with using a light microscope equipped...

Dobrzan?ski, L. A.; Labisz, K.; Wieczorek, J.; Konieczny, J.

2008-01-01

234

Effect of heat treatments on the mechanical behaviour of aluminium alloy foams  

International Nuclear Information System (INIS)

Two different closed-cell aluminium foams, manufactured by compact powder technology starting from 7075 and 6061 alloys, were studied with the aim of investigating the effect of heat treatments on their axial crushing behaviour. By means of scanning electron microscopy/energy-dispersive spectroscopy analyses, the crushing response was investigated in an attempt to understand how heat treatments may improve the absorbing efficiency of crashboxes

235

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Feliu Jr, S.; Bartolome?, Mª Jesu?s; Gonza?lez Ferna?ndez, Jose? Antonio; Lo?pez Serrano, Vi?ctor; Feliu, S.

2008-01-01

236

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

237

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Different states of residual stress generated by high-speed face milling in specimens of AA 7075-T6 aluminium alloy were meticulously evaluated. This assessment was carried out along the symmetry axes of the generated surfaces, and also in the centroids corresponding to the conventional and climb cutting zones. An indentation method, based on the use of a universal measuring machine, was employed to determine the normal and shear components of residual stress. It is noteworthy that the use of...

Di?az, F. V.; Mammana, C. A.; Guidobono, A. P. M.

2012-01-01

238

Elemental composition of films prepared on aluminium alloy in phosphate electgrolyte by microplasma anodization  

International Nuclear Information System (INIS)

The influence of inorganic additions introduced into phosphate electrolyte in the form of salts Na2MoO4, Na2WO4, KMnO4 and NaVO3 on element compopsition of coatings formed on aluminium alloy y microplasma anodization, their appearance, thickness, resistance to mechanical attrition, breakdown in the air and in 3% solution of NaCl during anodic polarization, was studied

239

Laser surface treatments for adhesion improvement of aluminium alloys structural joints  

International Nuclear Information System (INIS)

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

240

Fatigue behaviour of high strength AA 7012 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

The alloy 7012 (Al, 6.2% Zn, 2% Mg, 1% Cn, 0.13% Mn, 0.14% Zn, 0.04% Ti) belongs to the 7XXX family of high mechanical resistance alloys containing Zr as the principal additive. Produced in the form of extrusions, sheets and forgings, the alloy finds application in the defense, transportation and power industry fields. This paper presents the results of experimental fatigue tests (10/sup 7/ cycles) on 7020 in the T6 and T73 temper conditions and draws comparisons with corresponding test results on 7075 and 2024 type alloys. A comparative analysis of S-N curves obtained from plane bending and axial fatigue tests on smooth and notched specimens evidences the superior performance of 7020 in terms of higher strength and corrosion cracking resistance.

Di Russo, E.; Ragazzini, R.; Buratti, M.; Ferrarin, C. (Aluminia-ISML, Novara (Italy) Caproni Vizzola costruzioni aeronautiche, Somma Lombarda (Italy))

1990-02-01

 
 
 
 
241

On glass formation in rapidly solidified aluminium-based alloys  

International Nuclear Information System (INIS)

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

242

Tribological Properties of Aluminium 2024 Alloy Beryl Particulate MMC's  

Directory of Open Access Journals (Sweden)

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.

H.B. Bhaskar

2012-12-01

243

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

244

Stereometry specification of anodisation surface of casting aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties of an anodic layer formed on aluminum casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT on two casting aluminum alloys which both were founding by pressure die casting and gravity casting.Findings: The researches included analyze of the influence of chemical composition, geometry and r...

Konieczny, J.; Labisz, K.; Wieczorek, J.; Dobrzan?ski, L. A.

2008-01-01

245

Advances in aluminium alloy products for structural applications in transportation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Staley, J.; Lege, D.

1993-01-01

246

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

International Nuclear Information System (INIS)

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

247

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.

248

Corrosion inhibition of AA6060 aluminium alloy by lanthanide salts in chloride solution  

Energy Technology Data Exchange (ETDEWEB)

The electrochemical behaviour of AA6060 in 3.5% NaCl in the absence and presence of some rare earths has been studied by means of polarisation curves and impedance measurements. We find that the natural protective aluminium oxide layer is damaged after nearly 100 h of immersion time in the aggressive medium. The current-potential curves show that the corrosion resistance of the alloy is greatly enhanced by addition of lanthanide salts especially the cerium ion. This latter forms, on the alloy surface, a passive layer whose protective properties are reinforced by ageing in solution.

Allachi, H. [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Tetouan 93000 (Morocco); Chaouket, F. [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Tetouan 93000 (Morocco)], E-mail: fchaoukat@yahoo.fr; Draoui, K. [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Tetouan 93000 (Morocco)

2009-05-05

249

Corrosion inhibition of AA6060 aluminium alloy by lanthanide salts in chloride solution  

International Nuclear Information System (INIS)

The electrochemical behaviour of AA6060 in 3.5% NaCl in the absence and presence of some rare earths has been studied by means of polarisation curves and impedance measurements. We find that the natural protective aluminium oxide layer is damaged after nearly 100 h of immersion time in the aggressive medium. The current-potential curves show that the corrosion resistance of the alloy is greatly enhanced by addition of lanthanide salts especially the cerium ion. This latter forms, on the alloy surface, a passive layer whose protective properties are reinforced by ageing in solution.

250

Analysis of low cycle fatigue in AlMgSi aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study low-cycle fatigue tests were performed in two AlMgSi aluminium alloys with different chemical composition, namely 6082-T6 and 6060-T6 alloys, using standard round specimens and tube specimens, respectively. The tests were undertaken in strain control with a strain ratio R[var epsilon]=-1. The cyclic stress-strain curves were determined using one specimen for each imposed strain level. The low-cycle fatigue results are used for the characterisation of the cyclic plastic response ...

Borrego, L. P.; Abreu, L. M.; Costa, J. M.; Ferreira, J. M.

2004-01-01

251

Effect of aluminates on electrochemical properties of aluminium-indium-tin alloy  

International Nuclear Information System (INIS)

Anodic behavior of aluminium-indium-tin alloy in alkali-aluminate solution in the range of aluminate concentrations (0-3 mol l-1) at concentration of NaOH 2, 4, 6 mol l-1 and temperatures 40 and 75 Deg C was studied by method of removing potentiodynamic curves and chronopotentiogramms. Potential dissolution of the alloy at 75 Deg C differs by stability, but has a complex dependence from the composition of the solution. Potential shifts in the negative side at increasing concentration of alkali, and it shifts in the positive side at increasing content of aluminates. The latter fact is characteristic for the diluted solution

252

Microstructures and Properties of Aluminium-Magnesium Alloys with Additions of Manganese, Zirconium and Scandium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present work reports on the effect of Mn-, Zr- and Sc-additions upon hot deformation properties, recrystallization properties and mechanical properties for different temper conditions of Al-Mg alloys. It can be stated that the addition of Mn, Zr and Sc improves the recrystallization properties and the mechanical properties of Al-Mg alloys. It should be emphasised that the precipitation of the metastable cubic Al3Zr and the stable cubic Al3(Sc,Zr) is favourable in an aluminium-magnesium ma...

Johansen, Arve

2000-01-01

253

Analysis of intermetallic particles in AlSi1MgMn aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Mro?wka-nowotnik, G.; Sieniawski, J.; Wierzbin?ska, M.

2007-01-01

254

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

Science.gov (United States)

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.

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

2013-09-01

255

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

Directory of Open Access Journals (Sweden)

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.

Palomino Luis Enrique M.

2003-01-01

256

Influence of constitutional liquation on corrosion behaviour of aluminium alloy 2017A  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work was to investigate microstructural aspects of constitutional liquation in the aluminium alloy 2017A and to determine its effect on corrosion behaviour of this alloy. Non-equilibrium melting of the alloy in the naturally aged condition was provoked by rapid heating above the eutectic temperature and immediate cooling in air. Corrosion testing was performed by exposure to a marine onshore atmosphere. The microstructure examinations were carried out using light microscopy, scanning electron microscopy, X-ray energy dispersion and X-ray diffraction analysis. It was found that, due to rapid heating rate, coarse {theta} (Al{sub 2}Cu) particles were melted by constitutional liquation and this way introduced strong susceptibility of 2017A alloy to intergranular corrosion.

Kuznicka, B., E-mail: bogumila.kuznicka.@pwr.wroc.pl [Institute of Materials Science and Applied Mechanics, Wroclaw University of Technology, 50-370 Wroclaw (Poland)

2009-09-15

257

Influence of constitutional liquation on corrosion behaviour of aluminium alloy 2017A  

International Nuclear Information System (INIS)

The purpose of this work was to investigate microstructural aspects of constitutional liquation in the aluminium alloy 2017A and to determine its effect on corrosion behaviour of this alloy. Non-equilibrium melting of the alloy in the naturally aged condition was provoked by rapid heating above the eutectic temperature and immediate cooling in air. Corrosion testing was performed by exposure to a marine onshore atmosphere. The microstructure examinations were carried out using light microscopy, scanning electron microscopy, X-ray energy dispersion and X-ray diffraction analysis. It was found that, due to rapid heating rate, coarse ? (Al2Cu) particles were melted by constitutional liquation and this way introduced strong susceptibility of 2017A alloy to intergranular corrosion.

258

Effect of element additions on wear property of eutectic aluminium-silicon alloys  

Energy Technology Data Exchange (ETDEWEB)

The effects of cerium, zinc and zirconium additions and subsequent heat treatment on wear of the eutectic aluminium-silicon alloys have been investigated in dry sliding against a steel counterface by using a pin-on-disc machine. Wear surfaces and debris were examined by scanning electron microscopy. Wear characteristics of both binary Al-Si alloys and a commercial LM13 alloy, were also studied and compared with those of the Al-Si alloy containing the Ce, Zn and Zr. The k-values of the ALSI (Al-12.3%Si), LM13, ASMC-1 (Al-12.3%Si-0.75%Mg-0.26%Ce) and ASMC-1 (heat-treated) obtained are 5.795x10{sup -4}, 4.750x10{sup -4}, 4.311x10{sup -4} and 3.981x10{sup -4} mm{sup 3} N{sup -1} m{sup -1}, respectively. (orig.)

Harun, M. [Dept. of Physics, Kebangsaan Malaysia Univ., Selangor (Malaysia); Talib, I.A. [Dept. of Physics, Kebangsaan Malaysia Univ., Selangor (Malaysia); Daud, A.R. [Materials Science Programme, Kebangsaan Malaysia Univ., Selangor (Malaysia)

1996-06-01

259

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.

260

Increasing of founding properties of secondary aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose. To study the influence of metallurgical factors of production on casting properties of secondary aluminum alloy ??9?2. Methodology. For the experimental melts shaving amount in a charge, iron content and the quantity of modifier additive were chosen as independent variables. The components of modifier were being changed in the intervals of 25…40 % Na2CO3, 12…20 % SiC, 3…8 % Ti, the other – S. The microstructure of alloys was investigated under a light microscope, using the method of quantitative metallography. Influence analysis of certain parameters of alloys was conducted by mathematical statistics methods. The influence of shaving additions, iron and modifier amount on liquidity and porosity of the resulting alloys was studied. Findings. The paper shows that the increase of shaving content in the charge from 1 to 19 % and iron content in alloy from 0.66 to 2.34 % resulted in the decline of alloy liquidity on 30…35 %. Simultaneously the linear shrinkage reduction for 18…20 % and the porosity increase from 0.5 to 2.5 points were observed. The presented changes of alloy casting properties are conditioned by the amount of intermetallic phases of unfavorable form and its capacity for aeration. Increase of modifier additive from 0.02 to 0.15 % resulted in the liquidity increase on 10…15 %, the increase of linear shrinkage on 30…35 % and porosity decline from 2.5 to 0.5 points. At the same time a change of form of intermetallic phases and increase of their evenness were observed. Originality. The increase of iron concentration in silumin composition is accompanied by the decline of its liquidity. Thus, the rate of decline of alloy liquidity is proportional to the amount of dissolved iron. The character of iron influence is caused by formation of high temperature intermetallic compounds of the type Al3Fe, Al5SiFe, which promote the metal viscidity. Practical value. Practical use of the obtained scientific results would develop the technical solutions oriented to the quality indicator increase of silumin alloy.

O.V. Lyutova

2013-06-01

 
 
 
 
261

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)

262

Ion-implanted surface alloys in copper and aluminium  

International Nuclear Information System (INIS)

Alloys are usually formed by dissolving one species in another under thermal equilibrium. The choice of alloying species is therefore limited by chemical solubility and reactivity. High-dose ion implantation should make it possible to form surface alloys, under non-equilibrium conditions, even with species which are completely immiscible. Twenty different ions were implanted in Cu and Al single crystals, which are either immiscible or have very small expected solid solubilities. High doses are used to form the surface alloys. Rutherford backscattering and channelling of helium ions are employed to determine the substitutional fraction of the solute atoms, and the depth and amount of disorder in the substrate. Solid solubilities are derived from the measured substitutional fractions. Mo, Ru, Ta, and Bi in Cu; and Mo and Cu in Al show quite high solid solubilities. Hume-Rothery rules are violated in Cu but are obeyed well in Al. The disorder depths are anomalously high, 7-19 times the range of the implanted ions in Cu and 2-7 times the ranges in Al. The thermal stability of the exotic surface alloy of Mo in Cu and of the accompanying disorder is also studied. These results are interpreted in terms of the collision cascade theory, and a model based upon the effects of surface compressive stress. (author)

263

Electron irradiation of aluminium-zinc alloys. Pt. 2  

International Nuclear Information System (INIS)

A detailed experimental study of electron radiation-enhanced diffusion in aluminium-4.5 at% zinc is presented. The enhancement factor (Drad/Dthermal) was found to be dependent on dose rate, temperature and electron energy, and varied from ? 1 at 1700C to ? 104 at 250C. At low temperatures recombination dominates whereas at high temperatures linear annealing is the dominant mechanism for annihilation of point defects. The migration energy of vacancies is thus estimated to be 0.58±0.06 eV. The results are compared with a theoretical model. The model requires preferential transport of Zn atoms via the interstitial flux to reproduce the experimental results. The simple model Drad=fvDvCv+fiDiCi+... seems to underestimate Drad. (orig.)

264

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.

265

Structural properties of molten dilute aluminium-transition metal alloys  

Energy Technology Data Exchange (ETDEWEB)

The short-range order in liquid binary Al-rich alloys (Al-Fe, Al-Ti) was studied by x-ray diffraction. The measurements were performed using a novel containerless technique which combines aerodynamic levitation with inductive heating. The average structure factors, S(Q), have been determined for various temperatures and compositions in the stable liquid state. From S(Q), the pair correlation functions, g(r), have been calculated. The first interatomic distance is nearly temperature-independent, whereas the first-shell coordination number decreases with increasing temperature for all the alloys investigated. For the Al-Fe alloys, room-temperature scanning electron microscropy (SEM) studies show the formation of a microstructure, namely the existence of Al{sub 13}Fe{sub 4} inclusions in the Al matrix.

Pozdnyakova, I [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Hennet, L [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Mathiak, G [Institut fuer Raumsimulation, Deutsches Zentrum fuer Luft-und Raumfahrt e.V., Linder Hoehe, 51147 Cologne (Germany); Brillo, J [Institut fuer Raumsimulation, Deutsches Zentrum fuer Luft-und Raumfahrt e.V., Linder Hoehe, 51147 Cologne (Germany); Zanghi, D [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Brun, J-F [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Brassamin, S [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Bytchkov, A; Cristiglio, V; Veron, E; Matzen, G; Price, D L [Centre de Recherche sur les Materiaux a Haute Temperature, CNRS-CRMHT, 1d avenue de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Geandier, G [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, Cedex (France); Thiaudiere, D [Synchrotron Soleil, L' Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, Cedex (France); Moss, S C [Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Spaepen, F [Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Egry, I [Institut fuer Raumsimulation, Deutsches Zentrum fuer Luft-und Raumfahrt e.V., Linder Hoehe, 51147 Cologne (Germany)

2006-07-19

266

Determination of anisotropy in impact toughness of aluminium alloy 2024 T3 plate  

Science.gov (United States)

The research was aimed to quantify the existence of anisotropy in fracture toughness of aluminium alloy 2024 T3 plate (used in aircraft structural members). It was further needed to establish the direction in which the fracture toughness of aluminium alloy 2024 T3 plate is maximum and minimum. This could help ascertain the structural integrity of aircraft structural components; also while designing new components, the knowledge of variation in toughness with respect to direction helps in economizing dead weight of the aircraft. In this research, pursued at the College of Aeronautical Engineering, the anisotropy in toughness of aluminium alloy 2024 T3 plate was analysed using the Charpy V-notch impact toughness test. The effect of specimen orientation on the impact toughness values of the alloy was investigated and compared with known results to verify the reliability of the work and to ascertain the extent of anisotropy in fracture toughness of the said alloy. Charpy impact tests were carried out on ASTM E 23 standard specimens machined at a reference laboratory at room temperature (23° C +/- 2° C). Four different specimen orientations analysed for the purpose of this study were L-S, L-T, T-S and T-L directions. Subsequently, the results obtained at the research centre were then analysed and correlated with morphology of microstructure of the material to establish the reliability of the experimental results. Moreover, an analysis was also done to cater for the possible errors that could affect the fracture toughness values obtained from experimental results. It was concluded that the T-S orientation of the plate had maximum toughness, whereas, minimum toughness was observed in L-T direction.

Siddiqui, M. H.; Hashmi, F.; Junaid, A.

267

Pitting by corrosion in aluminium and Al-6201 alloy  

International Nuclear Information System (INIS)

The susceptibility of pure aluminum 6201 alloy to pitting was investigated in sodium chloride solutions through determination of the corrosion, repassivation and pitting potentials. Potentiodynamic polarization including scratching techniques were employed being also determined the type and relative amount of corrosion damage to the metals. The morphology of the attach was determined using scanning electrons microscopy (SEM). The results showed a similar performance for aluminum 6201 alloy and aluminum. It was also observed that an increase in chloride concentration resulted in a decrease in the corrosion, pitting and repassivation potentials of both materials. (Author) 19 refs

268

High speed twin roll casting of 6016 aluminium alloy strip  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: of this paper is to clear the possibility of high speed roll casting of aluminum alloy strip. In the bodyof the automobiles, a sheet of 6016 aluminum alloy is adopted for the outer panel. Therefore, casting of 6016was tried in this study. Characteristics of roll cast 6016 were investigated.Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designedto overcome the low castability of the twin roll caster.Findings: are as below. 6016 allo...

Sakaguchi, H.; Haga, T.; Watari, H.; Kumai, S.

2007-01-01

269

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

270

Effective hydrogen diffusion coefficient for solidifying aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An effective hydrogen diffusion coefficient has been calculated for two solidifying Al - 4.5 wt.% Cu and Al - 10 wt.% Cu alloys as a function of the volume fraction of solid. For this purpose, in situ X-ray tomography was performed on these alloys. For each volume fraction of solid between 0.6 and 0.9, a representative volume element of the microstructure was extracted. Solid and liquid voxels were assimilated to solid and liquid nodes in order to solve the hydrogen diffusion equation based o...

Felberbaum, M.; Landry-desy, E.; Weber, L.; Rappaz, M.

2011-01-01

271

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

Science.gov (United States)

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

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

2004-05-01

272

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

International Nuclear Information System (INIS)

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

273

Stereometry specification of anodisation surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work is presents the influence of casting method and anodic treatment parameters on properties of an anodic layer formed on aluminum casting alloys.Design/methodology/approach: Investigations were carried out on the laser profile measurement gauge MicroProf from company FRT on two casting aluminum alloys which both were founding by pressure die casting and gravity casting.Findings: The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts.Research limitations/implications: Contributes to research on anodic layer for aluminum casting alloys.Practical implications: Conducted investigations lay out the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, e.g. in the range of raising resistance on corrosion.Originality/value: The range of possible applications increases for example as materials on working building constructions, elements in electronics and construction parts in air and motorization industry in the aggressive environment.

J. Konieczny

2008-04-01

274

Accumulation of damage and fracture of aluminium alloy grains  

Directory of Open Access Journals (Sweden)

Full Text Available  Results of the investigation of  aluminum alloy AD-1 grains microhardness under fatigue and results of the fatigue crack monitoring are presented. The link of microhardness with kinetic characteristics of fracture process is determined. New approach for estimation of crystallographic orientation influence on fatigue life of single-crystal and crystallites is proposed.

?.?. ??????

2005-03-01

275

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Science.gov (United States)

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.

Cheng, Feng; Jiang, Shuyun; Liang, Jun

2013-09-01

276

Castability tests applied to an aluminium-copper alloy  

International Nuclear Information System (INIS)

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

277

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.)

278

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.

279

Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate  

Energy Technology Data Exchange (ETDEWEB)

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

Hill, Julie-Anne [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Markley, Tracey [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); CSIRO, Division of Materials Science and Technology, Clayton, Victoria (Australia); Forsyth, Maria, E-mail: maria.forsyth@deakin.edu.au [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Howlett, Patrick C. [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Hinton, Bruce R.W. [Department of Materials Engineering and Australian Centre of Excellence for Electromaterials Science, Wellington Rd, Monash University, Clayton, Victoria (Australia); Defence Science and Technology Organisation, Melbourne, Victoria (Australia)

2011-02-03

280

Process- and Alloy Development of Recyclable Aluminium Alloys : Recovery and Recrystallization Behavior of a Selection of AlMn-model Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A study of the effect of various amounts of manganese in solid solution on the recovery and recrystallization behavior of an AlMn-alloy, for different annealing conditions after different degrees of deformation (cold rolling) has been carried out. The alloy studied was a 3xxx-type model alloy with 0.5 wt% Fe, 0.15 wt% Si and 1.0 wt% Mn. The studies were a contribution to the MOREAL-project, where the main objective is to quantify and characterize the softening behavior of recyclable aluminium...

Flatøy, Jarl Erik Morsund

2011-01-01

 
 
 
 
281

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

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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.

T. Haga

2013-07-01

282

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

Science.gov (United States)

Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of ?-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.

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

2007-06-01

283

Dilatometer study of rapidly solidified aluminium-silicon based alloys  

Energy Technology Data Exchange (ETDEWEB)

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 Al{sub 100-x}Si{sub x} (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.

Varga, B [University TRANSILVANIA, B-dul Eroilor nr. 29, 500036, Brasov (Romania); Fazakas, E; Hargitai, H [Inst. for Materials Science and Technology, Bay Z. Foundation, Fehervari ut, 130., H-1116 Budapest (Hungary); Varga, L K, E-mail: varga@szfki.h

2009-01-01

284

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.

285

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: • The DSC method was used for developing continuous cooling precipitation diagrams. • The quench-induced particles were observed by SEM for alloys AA7150 and AA7020. • There were more quench-induced particles in alloy AA7150. • Quench sensitivity of Al alloys can be evaluated by using the CCP diagrams. -- Abstract: Two commercial 7xxx series aluminium alloys with different solute contents and different quench-induced precipitation behaviour have been investigated by using a specialised differential scanning calorimetry (DSC) technique to record exothermal heat outputs during continuous cooling. Together with hardness testing and microstructural analysis, this DSC method was used to develop continuous cooling precipitation (CCP) diagrams for alloys AA7150 and AA7020. The results show that the total precipitation heat for each alloy decreases with increasing cooling rate. However, the excess specific heat at a given cooling rate in alloy AA7150 is much higher than that in alloy AA7020. It is evident that there are atleast three different quench-induced reactions in different temperature regimes for alloy AA7150 cooled at various linear cooling rates, but only equilibrium MgZn{sub 2} (?-phase) and Al{sub 2}CuMg (S-phase) particles were observed by scanning electron microscopy (SEM). There are at least two main precipitation peaks that can be found for alloy AA7020, which correspond to Mg{sub 2}Si and MgZn{sub 2} (?-phase). Furthermore, a method is developed to evaluate the quench sensitivity of an alloy based on a determination of the critical cooling rate. The maximum hardness values are reached at cooling rates that are faster than or similar to the critical cooling rate.

Zhang, Y., E-mail: yong.zhang@outlook.com [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Milkereit, B. [University of Rostock, Faculty of Mechanical Engineering and Marine Technology, Chair of Materials Science, 18051 Rostock (Germany); University of Rostock, Institute of Physics, Polymer Physics Group, 18051 Rostock (Germany); Kessler, O. [University of Rostock, Faculty of Mechanical Engineering and Marine Technology, Chair of Materials Science, 18051 Rostock (Germany); Schick, C. [University of Rostock, Institute of Physics, Polymer Physics Group, 18051 Rostock (Germany); Rometsch, P.A. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia)

2014-01-25

286

Wear Properties of Alumina Particles Reinforced Aluminium Alloy Matrix Composite  

Directory of Open Access Journals (Sweden)

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

Faiz Ahmad

2011-01-01

287

Continuous roll casting of aluminium alloys – casting parameters analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main goal of the paper was to present the influence of casting parameters on casting conditions and interference of casting parameters on the final strip characteristics such as constant strip thickness, surface quality and roughness of aluminum alloys sheet 6,30 to 6,50 mm thick. The study shows that casting speed, roll force and roll gap should have the greatest influence on the final strip thickness, and that the examined parameters agree well with the theoretical standpoints.

Krstic? Vukelja, E.; Duplanc?ic?, I.; Lela, B.

2010-01-01

288

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

289

An aluminium alloy for a non breeding blanket NET/INTOR  

International Nuclear Information System (INIS)

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

290

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)

291

An RF-GD-OES calibration for surface analysis on aluminium alloys  

International Nuclear Information System (INIS)

Full text: Glow-Discharge Optical Emission Spectrometry (GD-OES) is a powerful technique for the rapid analysis of elements in a solid surface as a function of depth DC-GD-OES allows depth profiling on electrically conductive surfaces only, and has proven to be difficult for the analysis of insulating layers, such as oxides. However, the technique of radio-frequency (RF) GD-OES has the advantage of being able to depth profile through multiple layers, both conducting and insulating. In this work, a LECO GDS-850A spectrometer was calibrated for aluminium, oxygen, and other elements, with the RF source installed A quantitative depth profile for a sample of tempered aluminium alloy 7475 is presented and compared with earlier work. Copyright (2005) Australian Institute of Physics

292

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

Science.gov (United States)

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.

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

2007-04-01

293

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)

294

Surface morphology, composition and thermal behavior of tungsten-containing anodic spark coatings on aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Anodic spark coatings on aluminium alloy were prepared in aqueous electrolytes with sodium tungstate. The influence of boric acid addition in the electrolyte on the surface morphology, elemental and phase composition of the coatings was investigated. In both cases the coatings contained O, Al and W. The coatings obtained in electrolyte with boric acid and sodium tungstate contain also B at approximately 1 at.%. Scanning electron microscopy indicated that the coatings had three layers: the grey underlayer of anodic alumina, the second black layer of crystalline or amorphous aluminium tungstate agglomerated into fibers and the outer green layer of WO{sub 3}. It was proposed that isopoly- and heteropolyanions in the electrolyte used take part in the coating growth.

Lukiyanchuk, I.V.; Rudnev, V.S.; Kuryavyi, V.G.; Boguta, D.L.; Bulanova, S.B.; Gordienko, P.S

2004-01-01

295

Surface morphology, composition and thermal behavior of tungsten-containing anodic spark coatings on aluminium alloy  

International Nuclear Information System (INIS)

Anodic spark coatings on aluminium alloy were prepared in aqueous electrolytes with sodium tungstate. The influence of boric acid addition in the electrolyte on the surface morphology, elemental and phase composition of the coatings was investigated. In both cases the coatings contained O, Al and W. The coatings obtained in electrolyte with boric acid and sodium tungstate contain also B at approximately 1 at.%. Scanning electron microscopy indicated that the coatings had three layers: the grey underlayer of anodic alumina, the second black layer of crystalline or amorphous aluminium tungstate agglomerated into fibers and the outer green layer of WO3. It was proposed that isopoly- and heteropolyanions in the electrolyte used take part in the coating growth

296

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Bru?na, M.; Sla?dek, A.

2011-01-01

297

Effect of tool profile and fatigue loading on the local hardness around scratches in clad and unclad aluminium alloy 2024  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 and are attributed to whether the tool makes the scratch by a 'cutting' ...

Khan, M. K.; Fitzpatrick, M. E.; Hainsworth, S. V.; Edwards, L.

2009-01-01

298

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper reviews contemporary research in the area of hybrid composites based on zinc and aluminium alloys reinforced with SiC and graphite particles. Metal matrix composites (MMCs) based on ZA matrix are being increasingly applied as light-weight and wear resistant materials. Aluminium matrix composites with multiple reinforcements (hybrid AMCs)are finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforc...

Dz?unic?, D.; Pantic?, M.; Miloradovic?, N.; Stojanovic?, B.; Babic?, M.; Mitrovic?, S.

2012-01-01

299

Influence of Magnesium Nitrate on the Corrosion Performance of Sol-Gel Coated AA2024-T3 Aluminium Alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Traditional anti-corrosion technology has relied heavily on using reducible metal species, predominantly hexavalent chromium (Cr(VI)), for protecting reactive metal alloys such as aluminium which is extensively used in the aerospace sector. However, the impending changes in the use of Cr(VI) in Europe and the United States have forced aerospace manufacturers to examine alternative materials for protecting aluminium. One of the most promising alternatives being investigated are organosilane ba...

Varma, Rajath; Duffy, Brendan; Cassidy, John

2009-01-01

300

Continuous roll casting of aluminium alloys – casting parameters analysis  

Directory of Open Access Journals (Sweden)

Full Text Available The main goal of the paper was to present the influence of casting parameters on casting conditions and interference of casting parameters on the final strip characteristics such as constant strip thickness, surface quality and roughness of aluminum alloys sheet 6,30 to 6,50 mm thick. The study shows that casting speed, roll force and roll gap should have the greatest influence on the final strip thickness, and that the examined parameters agree well with the theoretical standpoints.

E. Krsti? Vukelja

2010-04-01

 
 
 
 
301

Back flow creep phenomena in short fibre reinforced aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The present study investigates back flow after creep unloading of a squeeze cast metal matrix composite (MMC), for an AlZn11 matrix alloy reinforced with 8 volume-% Saffil fibres. The material was deformed to a certain amount of strain under a stress of 30 MPa. Then it was unloaded and the kinetics of back straining was measured. It was found that after unloading back straining occurs and strains accumulated which are significantly higher than expected for elastic unloading. It is shown that back straining of the MMC represents a creep process which is driven by the elastic strain energy stored in the fibres. (orig.)

Kaustraeter, G.; Wagner, M.; Skrotzki, B.; Eggeler, G. [Inst. for Materials, Ruhr-Univ. Bochum (Germany); Yawny, A.

2002-07-01

302

The microstructure and precipitation kinetics of a cast aluminium alloy  

International Nuclear Information System (INIS)

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

303

Desain Dan Analisis Velg Mobil Berbasis Aluminium Alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wheels on the car is the frame of a wheel that holds the style and stress as a result of the weight of the vehicle and the impact or blows from the road surface. The blow from the road surface can result in voltage and deformation on wheels. Aluminum alloy wheels have a region called the critical area is located in the hub, spoke, and flange. One of the strengths wheels in receiving stress is affected by the number of spokes. To overcome these problems required an analysis of the number of sp...

Dalimunthe, Harri Rusadi

2014-01-01

304

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

Science.gov (United States)

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

Rittapai, Apiwat; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

2014-01-01

305

Analytic and experimental study for light alloy aluminium panels under compression  

Directory of Open Access Journals (Sweden)

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.

A. Fayza

2007-11-01

306

Strength of the Aluminium Alloy 6082-T6 Under High Strain-Rate Conditions  

Science.gov (United States)

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

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

2007-12-01

307

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

International Nuclear Information System (INIS)

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

308

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

309

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

310

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

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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.

Marina Fuser Pillis

2008-09-01

311

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2008-09-01

312

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)

313

Reciprocal dry sliding wear behaviour of B4Cp reinforced aluminium alloy matrix composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work, AlSi9Cu3Mg alloy matrix composites reinforced with 15 and 19% (vol.) B4Cp were produced by squeeze casting route at 850 ??C under low vacuum. Titanium-containing flux (K2TiF6) was used to promote the wetting between B4C and liquid aluminium metal. It was found, from the microstructural observations, that the wetting improved by the formation of a thin Ti-rich reaction layer. In order to investigate the wear properties, the samples were subjected to reciprocati...

Toptan, Fatih; Kerti, Isil; Rocha, Lu S. A.

2012-01-01

314

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

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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,...

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

2013-01-01

315

Deformation-induced small-angle scattering contrast in aluminium alloys  

International Nuclear Information System (INIS)

Small-angle neutron scattering experiments have been performed on a uniformly stretched specimen (uniform elongation 18.5%) of commercial thin-sheet wrought aluminium alloy AA6013 (Al-Mg-Si-Cu) aged at room temperature. Comparison with undeformed material revealed characteristic deformation-induced anisotropy of the two-dimensional scattering pattern, which can be interpreted as being due to deformation-induced arrangements of preferentially aligned dislocation segments. The effect of anisotropy is larger but of the same type as that of small-angle X-ray scattering patterns obtained from the crack-tip plastic zone of cracked specimens

316

Parametric study of friction stir spot welding of aluminium alloy 5754  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2014-01-01

317

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2007-01-01

318

Oxygen Determination in Aluminium Iron Pre-Alloyed Powders by Nuclear Reaction Analysis  

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Oxygen content in aluminium alloys Al-3Fe or Al-8Fe-1Zr (wt%) maked from air atomized powders by a sinter-forging process (in the range of 320 to 500 °C) has been determined by using a Nuclear Reaction Analysis (N.R.A). The amount of Oxygen, either in pressed compacts or in hot-forged samples was measured with an accuracy of ± 15% and found to be equal to 1-2 wt%. In fact, during atomization in air and/or their subsequent storage, these powders have adsorbed a rather important quantity of o...

Frontier, J.; Trouslard, Ph; Chekroud, S.; Cizeron, G.

1995-01-01

319

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

International Nuclear Information System (INIS)

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

320

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

International Nuclear Information System (INIS)

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

 
 
 
 
321

Grain refining of aluminium alloys and silicon by means of boron-nitride particles  

Energy Technology Data Exchange (ETDEWEB)

Investigations were carried out to grain refine the aluminium alloys Al-6Si (all compositions given in wt.%) and Al-12Si as well as pure silicon by means of inoculation using boron nitride nano-particles. Comparative tests were performed using both conventional grain refiners based on titanium as well as without inoculants. Analyses were performed using scanning electron microscopy, tensile testing, thermographic and metallographic techniques. In doing this, a significant effect on grain refining is verified by inoculating using boron nitride which exceeds the effect of conventional grain refiners. (orig.)

Wulf, Eric; Seitz, Jan-Marten; Schaper, Mirko; Bach, Friedrich-Wilhelm [Leibniz Univ. of Hannover, Garbsen (Germany). Inst. of Materials Science; Alphei, Lukas David; Westphal, David; Becker, Joerg August; Feldhoff, Armin [Leibniz Univ. of Hannover, Garbsen (Germany). Inst. of Physical Chemistry and Electrochemistry

2013-03-15

322

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

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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.

K. Mroczka

2008-10-01

323

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

Science.gov (United States)

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

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

1998-09-01

324

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

Science.gov (United States)

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

Rabah, Mahmoud A

2003-01-01

325

Development of porous anodic films on 2014-T4 aluminium alloy in tetraborate electrolyte  

International Nuclear Information System (INIS)

Anodic film growth on 2014-T4 aluminium alloy at 60 V in 50 g l-1 di-sodium tetraborate at 60 deg. C has been examined by transmission electron microscopy and Rutherford backscattering spectroscopy. Initial film growth proceeds at relatively high efficiency on the initially etched and desmutted alloy. During the subsequent period of current decline, the reactive electrolyte species penetrate the outer film at preferred regions, establishing conditions for pore development by field-assisted dissolution. In the alkaline electrolyte, such field-assisted dissolution also appears to proceed locally, probably through mechanical disruption of the film, giving rise to a feathered film morphology. The oxidation of copper from the alloy, in the presence of an enriched layer of copper, developed largely by initial etching, also influences film morphology through parallel oxygen gas generation, creating oxygen-filled voids. Such gas-filled voids may rupture or be removed from the alumina film material through field-assisted dissolution at the pore base. In the former case, cracking allows access of the anodizing electrolyte to the enriched alloy/film interface, with subsequent dissolution of the enriched layer and local film growth; these give rise to lateral porosity in addition to that from pores passing perpendicularly to the alloy surface. The efficiency of anodizing is about 12%, with losses from Al3+ ion ejection, field-assisted dissolution, oxygen gason, field-assisted dissolution, oxygen gas generation, film rupture, interface dissolution and local film repair

326

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

International Nuclear Information System (INIS)

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

327

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

328

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.

329

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

International Nuclear Information System (INIS)

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

330

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.

331

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

332

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

Directory of Open Access Journals (Sweden)

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.

Mohedano, Marta

2014-03-01

333

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 distributmogenizes 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.

334

Site specific SEM/FIB/TEM for analysis of lubricated sliding wear of aluminium alloy composites  

International Nuclear Information System (INIS)

Although extensive research has been undertaken into the dry sliding wear of aluminium alloys, only limited work has been reported on lubricated wear. In this paper, the lubricated sliding wear of some powder derived aluminium alloy composites is reported. Stereo pairs of the worn surface were obtained in the SEM and digitally reconstructed to give an accurate projection of the surface topography. Analysis of the average surface roughness (Ra) along chosen sections provided quantitative information about the wear mechanism. Following this, dual beam focused ion beam (FIB) was undertaken to further explore the features revealed by the SEM surface reconstructions, with TEM sections removed from selected regions. Surface deformation was confined to a narrow layer, typically 1?m thick. Subgrain size within the subsurface layer was comparable to that found in dry sliding wear tests. Reinforcement fracture occurred in the surface particles only. The resultant fragments were often incorporated back into the surface following detachment, such that the total volume fraction reinforcement at the surface was greater than in the bulk. Thus, the dynamic surface topography was a result of three factors: surface deformation, local detachment of reinforcement and re-incorporation of the fragments back into the surface

335

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

Science.gov (United States)

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

List, G.; Girot, F.

2003-09-01

336

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

337

Casting and irradiation damage studies of 8001 series of Aluminium alloys for nuclear research reactor structural applications  

International Nuclear Information System (INIS)

Application of materials in nuclear science and technology is one of the most important difficulties in nuclear industry because in these applications not only good mechanical, thermal and electrical properties of materials should be considered but also the behavior of these structural materials under nuclear irradiation and degradation in their crystalline structure and hence change in final properties of materials are important. Investigation of the effect of nuclear radiation on metals and alloys used in nuclear industry made it possible to select the best materials for these applications and these days with more progress in nuclear industry more complicated research work have been undertaken. To perform experimental research to determine the nature and the extent of radiation damage in mechanical properties of alloys such as yield point, increase in shattering and reduction in ductility as well as reduction in toughness and impact resistance are the first step to evaluate the mechanical stability and effectiveness of alloys in nuclear reactor applications. With respect to their mechanical properties specification as well as resistance against corrosion Aluminium and its alloys have many applications in nuclear technologies. For fuel cladding, structural alloys for channels, pipes and reactor storage in service conditions with up to 200 deg C temperature aluminium alloys have many applications. In this research work casting of 8001 series aluminium alloys and therm of 8001 series aluminium alloys and thermomechanical treatment, preparation of standard tension test specimen and neutron irradiation with different doses and finally different mechanical testing to investigate the effects of radiation damage have been carried out and the results have presented

338

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.)

339

Evolution of Artificial Neural Network (ANN) model for predicting secondary dendrite arm spacing in aluminium alloy casting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 predicted 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 c...

Hanumantha Rao, D.; Tagore, G. R. N.; Ranga Janardhana, G.

2010-01-01

340

Sliding wear behaviour of novel AA2124 aluminium alloy/Ni{sub 3}Al composites  

Energy Technology Data Exchange (ETDEWEB)

Novel aluminium alloy (2124) matrix composites reinforced by 15 vol% Ni{sub 3}Al intermetallic particles were prepared by a powder metallurgy route. The aluminium alloy matrix was prepared by gas atomisation, while the Ni{sub 3}Al was prepared by self propagating high temperature synthesis (SHS). Following blending, the particulates were consolidated by extrusion at 500 C and an extrusion ratio of 30:1, producing a homogenous distribution of Ni{sub 3}Al. A 2124/15 vol%SiC composite and 2124 monolithic alloy were produced in the same manner. Wear testing was undertaken using a block on ring configuration against an M2 steel counterface at 0.94 m/s with loads of 22-91 N. At loads of 22 and 42 N, the 2124/Ni{sub 3}Al composites provided superior wear resistance to the monoliths, while at 91 N the opposite was observed. The 2124/SiC produced the best wear performance at all loads. The Ni{sub 3}Al largely retained its original shape after wear testing at 22 and 42 N, but was plastically deformed and fragmented at 91 N. No evidence of SiC fragmentation or fracture was observed at any load. A mechanical mixed layer (MML) was formed at all loads for all samples, the thickness of which increased approximately linearly with load. The thickness of the mechanically mixed layer was substantially larger for the monolith compared with both composites. The relationship between microstructure and wear rate is discussed. (orig.)

Wang, Y.; Rainforth, W.M.; Jones, H. [Dept. of Engineering Materials, Univ. of Sheffield, Sheffield (United Kingdom); Lieblich, M. [Dept. of Metallurgia Fisica, Centro Nacional de Investigaciones Metallurgicas, CENIMCSIC, Madrid (Spain)

2002-07-01

 
 
 
 
341

Microstructure of friction stir welding of aluminium alloy to magnesium alloy  

International Nuclear Information System (INIS)

The microstructure of the interface between Al alloy and Mg alloy joined by friction stir welding is characterized using electron microscopy. The intermetallic compound reaction layer has a thickness of about 1 ?m and consists mainly of fine-grained Al12Mg17 phase. Further nanosize-grained Al3Mg2 inclusions in close proximity to the Al12Mg17 layer appear in the Al alloy.

342

The nearest surrounding of aluminium atoms and details of the electronic structure of Al90FexCe10-x (x = 3, 5, 7) alloys  

International Nuclear Information System (INIS)

One derived spectra of X-ray absorption beyond aluminium K-edge in Al90FexCe10-x (x = 3, 5, 7) alloys. Using method of total multiple scattering one analyzed theoretically Al90FexCe5 spectrum beyond aluminium absorption K-edge. On the basis of comparison of theoretical and experimental data one stipulated the most probable model of aluminium local surrounding in that alloy. One determined density of free electron states of aluminium and iron within conductivity range. It was found that at interaction of aluminium p-states with iron d-states one observed forcing out of aluminium p-states by iron d-states

343

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Aramide, Fatai Olufemi; Ibitoye, Samuel Ademola; Fagade, Obafunmilola Oluwatosin

2012-01-01

344

Microstructure and mechanical properties of C355.0 cast aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The main task of this work was to study the solidification process through analysis of the DSC curves that were obtained at solidification rate of 5 K/min. During C355.0 alloy solidification an amount of different intermetallic phases may form. Their volume fraction, chemical composition and morphology exert significant influence on a technological and mechanical properties of the aluminium alloys. Therefore the examination and identification of intermetallic phases in examined alloy is very important part of complex investigation. In this research the effect of precipitation hardening process on the microstructure and mechanical properties of C355.0 alloy has also been investigated.Design/methodology/approach: To study the solidification process differential scanning calorimetry (DSC was used. Hardness measurements have been utilized to examined the effect of a precipitation hardening (T6 on the mechanical properties. The plastic and mechanical properties were evaluated by uniaxial tensile test at room temperature. To identify intermetallics in C355.0 alloy optical light microscopy (LM, X-ray diffraction (XRD, scanning (SEM and transmission (TEM electron microscope were used.Findings: The results show that the as-cast microstructure of C355.0 alloy after slow solidification at a cooling rate 5K/min, consisted a wide range of intermetallics phases. The microstructure of investigated C355.0 alloy included: ?-Al5FeSi, ?-Al12(FeMn3Si, Al2Cu, Q-Al5Cu2Mg8Si6, Si and Mg2Si phases. Significant changes in as-cast microstructure and mechanical properties followed after artificial aging due to a precipitation strengthening process were observed.Practical implications: The aim of this work was to analyze the solidification process and how T6 heat treatment influenced the microstructure and mechanical properties of C355.0 alloy. Additionaly this paper proposes the best experimental techniques for analysis of the intermetallic phases occurring in the cast and T6 condition.Originality/value: The paper has provided essential data about influence of solidification process and aging parameters on the microstructure and mechanical properties of C355.0 alloys

J. Sieniawski

2011-02-01

345

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

International Nuclear Information System (INIS)

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

346

Influence of the ageing on mechanical properties of the aluminium alloy AlSi9Mg  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The goal of this paper was study the influence of temperature and time in the age-hardening on theselected mechanical properties and hardness of the AlSi9Mg alloy.Design/methodology/approach: The efficiency of the age-hardening were tested on laboratory specimensthrough the statically tension test on ZWICK/Z100. Damages were critically assessed through SEM investigations.Evaluation the mechanical properties of prepared samples were realized by solutioning and then ageing in differentperiods of time.Findings: Adequately selected time of the ageing improved the hardening and plasticity and reduce the tendencyof aluminium to formation of coagulations.Research limitations/implications: The described investigations were limited to changes the mechanicalproperties of the specimens in different periods of time of aging, in solid temprature. In future research worksshould show the influence of change of temperature process on studied AlSi9Mg alloy, as well as differentlightweight alloy.Originality/value: The paper contributes to better understanding and recognition the mechanisms of agehardening.

L.A. Dobrza?ski

2008-05-01

347

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

Science.gov (United States)

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.

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

2014-09-01

348

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

International Nuclear Information System (INIS)

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

349

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

International Nuclear Information System (INIS)

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 UNIVERSITY OF 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 alloys from the Al-Fe-V, Al-Fe-Mo, Al-Cr-Ni and Al-Mn-Ni systems are presented and discussed. Their stability for long exposures at temperatures up to 350 C is demonstrated on the basis of fine microstructural investigations and mechanical tests. The cross effect of the Iron content and the powder size distribution is detailed in the case of the gas atomization process for the Al-Fe-V system. The results obtained on the most promising products are detailed and compared to those available on existing 8009 and 8019 alloys. Potential applications on aerospace structures are described. (orig.)

350

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

Energy Technology Data Exchange (ETDEWEB)

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 UNIVERSITY OF 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 alloys from the Al-Fe-V, Al-Fe-Mo, Al-Cr-Ni and Al-Mn-Ni systems are presented and discussed. Their stability for long exposures at temperatures up to 350 C is demonstrated on the basis of fine microstructural investigations and mechanical tests. The cross effect of the Iron content and the powder size distribution is detailed in the case of the gas atomization process for the Al-Fe-V system. The results obtained on the most promising products are detailed and compared to those available on existing 8009 and 8019 alloys. Potential applications on aerospace structures are described. (orig.).

Barbaux, Y. (Aerospatiale, Centre Commun de Recherches Louis Bleriot, 92 Suresnes (France)); Pons, G. (Aerospatiale, Centre Commun de Recherches Louis Bleriot, 92 Suresnes (France))

1993-11-01

351

Electrochemical reactivity of laser-machined microcavities on anodised aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The electrochemical reactivity of laser-machined microcavities on anodised aluminium alloys was investigated. Excimer pulse laser (308 nm) depassivation of both absorbing and transparent oxides was carried out in aqueous electrolytes while simultaneously recording the current in an electrochemical potentiostatic three-electrode set-up. Laser irradiation of the absorbing oxide resulted in ablation, whereas the transparent oxide was delaminated by the ablation action of the underlying alloy substrate (spallation). Current transients could be related to ion-conducting flaws generated mechanically in the shock-affected zone (SAZ). Ionic transport through the growing oxide or through the flaw channels controlled the repassivation rate. The repassivation current transients was modelled by a simple equivalent circuit consisting of a capacitor and a resistance in series. The behaviour of the derived resistance values describes the ion conduction rate in cracks or of growing oxide phases. The potential dependence of capacitance during the ablation of the alloy substrate suggests that the dielectric properties of the regenerated oxide films depend drastically on the formation kinetics.

Kautek, Wolfgang; Daminelli, Grazia

2003-09-30

352

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

Directory of Open Access Journals (Sweden)

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

Eramah Abdsalam M.

2014-01-01

353

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)

354

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

Directory of Open Access Journals (Sweden)

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.

M. Adamiak

2008-12-01

355

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

Directory of Open Access Journals (Sweden)

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

M. Thirumal Azhagan

2014-03-01

356

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

357

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

International Nuclear Information System (INIS)

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

358

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

International Nuclear Information System (INIS)

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

359

The influence of heat treatment on strain hardening and strain-rate sensitivity of aluminium alloys for aerospace  

International Nuclear Information System (INIS)

The importance of aluminium sheet forming in aero spatial industry makes it necessary to study those parameters that control the behaviour of material during the process. Tensile properties, strain hardening exponent n and strain rate sensitivity m in 7075 aluminium alloys have been studied to relate forming behaviour with control parameters. Tests on O, W, and T6 tempers have been performed, to determine the influence of heat treating. Finally, both longitudinal and long transverse directions tensile specimens have been obtained to analyze the anisotropy. (Author) 9 refs

360

XPS valence bands of La, Ce and Gd and their aluminium alloys  

International Nuclear Information System (INIS)

The XPS valence band spectra of La, Ce and Gd metal and of their aluminium alloys show the 5d band in La metal at 0.8 eV below the Fermi energy with a width of about 1.5 eV; in Ce the 4f band and 5d band are at 0.5 eV and 1.7 eV below the Fermi energy with widths of 0.7 eV and 1.5 eV respectively. The Gd 5d band is very similar to the La 5d band, while the 4f level is well localized at 8.0 eV below the Fermi energy. (author)

 
 
 
 
361

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.

362

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

Energy Technology Data Exchange (ETDEWEB)

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, {alpha}-Al(Fe,Mn)Si acts as permanent cathodic sites.

Allachi, H. [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Avenue lbn Battouta, BP 2121, Tetouan 93000 (Morocco); Chaouket, F., E-mail: fchaoukat@yahoo.f [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Avenue lbn Battouta, BP 2121, Tetouan 93000 (Morocco); Draoui, K. [Laboratoire de Physico-Chimie des Interfaces et Environnement, Faculte des Sciences, Universite Abdel Malek Essaadi, Avenue lbn Battouta, BP 2121, Tetouan 93000 (Morocco)

2010-02-18

363

Mechanical and corrosion properties of aluminium alloy EN AW 6082 after severe plastic deformation (SPD  

Directory of Open Access Journals (Sweden)

Full Text Available The aim had been to study changes in the properties of aluminium alloy AlSiMgMn. Influence of SPD of the mechanical properties had increased (Rm by 86 MPa, Ro0,2 by 175 MPa, while A had decreased to 20 %. The corrosion potentials had been evaluated in the environment of H2O and in SARS. After SPD was observed in the environment of H2O, that resistance had increased by -218 mV and after exposure up to 1 000 min there was a slight deterioration of resistance in SARS. On the surface specimens after SPD were observed higher quantities of corrosion products. After SPD was observed fatigue characteristics in torsional stress in the oblique branches Wohler curves showed favourable characteristics of about 35 %.

P. Lacková

2015-01-01

364

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1998-05-01

365

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

Science.gov (United States)

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

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

2012-08-01

366

Fatigue behaviour of post weld heat treated electron beam welded AA2219 aluminium alloy joints  

International Nuclear Information System (INIS)

This paper reports the effect of post weld heat treatment on fatigue behaviour of electron beam welded AA2219 aluminium alloy. An attempt has been made to enhance the fatigue strength of the electron beam welded joints through post weld heat treatment methods such as solution treatment, artificial aging, solution treatment and artificial aging. Electron beam welding machine with 100 kV capacity has been used to fabricate the square butt joints. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN has been used to evaluate the fatigue life of the welded joints. Of the three post weld heat treated joints, the solution treated and aged joints are enduring higher number of cycles under the action of cyclic loads

367

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

International Nuclear Information System (INIS)

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.

368

Friction Stir Processing of an AlSi6Cu4 cast aluminium alloy  

Directory of Open Access Journals (Sweden)

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

M.St. W?glowski

2011-04-01

369

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

International Nuclear Information System (INIS)

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

370

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

Science.gov (United States)

Ultrasonic fatigue testing equipment is presented that is capable of performing constant amplitude (CA) and variable amplitude (VA) experiments at different constant load ratios. This equipment is used to study cyclic properties of aluminium alloy 2024-T351 in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime at load ratios R=-1 and R=0.5. CA loading does not reveal a fatigue limit below 10¹? cycles. Cracks leading to VHCF failure start at broken constituent particles. Specimens that survived more than 10¹? cycles at R=-1 contain non-propagating cracks of lengths below grain size. Resonance frequency and nonlinearity parameter ?(rel) show changes of vibration properties of specimens at low fractions of their VHCF lifetime. VA lifetimes are measured in the HCF and VHCF regime and compared with Miner calculations. Damage sums decrease with decreasing load (and increasing mean lifetimes) and are lower for R=0.5 than R=-1. PMID:23548512

Mayer, H; Fitzka, M; Schuller, R

2013-12-01

371

RETROGRESSION AND RE-AGING TREATMENT OF AA 7049 ALUMINIUM ALLOY  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of retrogression and re-aging (RRA on the strength and corrosion performance was evaluated for AA 7049 aluminium alloy. Samples from extruded profiles were treated to T6 and T73 temper. Also Retrogression was performed at four different temperatures between 1800C – 2400C for various times followed by re-aging at1200C. The properties like ultimate tensile strength (UTS, hardness and conductivity measurement,intergrannular corrosion and exfoliation studies are presented. The results of experimental work indicate thatRRA treatment enhances the strength equivalent to or greater than AA 7049 at T6 temper and exfoliation corrosion resistance comparable to T73 temper.

R.RANGANATHA

2011-07-01

372

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.

373

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Gustafsson, Sofia

2011-01-01

374

Extrusion Die Design and Process Simulation of High Strength Aluminium Alloy  

Science.gov (United States)

Aluminium alloy 7075 is an excellent metal with the features of high strength and light weight. The solid extruded parts of AL 7075 are commonly used in the structure members of airplanes and bicycles. The seamless tubes of AL 7075 are also used, while tubes with welding line (seamed) are mainly made by the other types of aluminium alloy. This research is focused on the extrusion die design and process simulation of the rectangular seamed AL 7075 tubes. A new die design concept is proposed to increase the welding pressure in the chamber to solve the problem of poor welding ability of AL 7075. The key points of welding ability improvement are the higher welding pressure, the crucial billet temperature, and the extrusion speed. The designed extrusion die should have some features to control the material flow and achieve the higher welding pressure. In this paper, not only use the traditional die bearing and the welding chamber, but also add a conical guiding chamber (specified with chamber height and width) to improve the material flow control. Finite element method is used to simulate the extrusion process and evaluate the effect of die design parameters for a seamed rectangular 7075 tube extrusion. The die stress should be considered carefully because of increasing the welding pressure also increases the die stress. Taguchi method is used to obtain the optimum combination of die design parameters to get higher welding pressure and keep the die stress at a reasonable low level. The method proposed in this paper is able to increase the welding pressure with the cost of reasonable die stress.

Sheu, Jinn-Jong; Chen, Yan-Hong; Su, Guan-Cheng

2011-01-01

375

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.

376

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

Science.gov (United States)

A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al-Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO(3) on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO(3) containing 10-20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al-Zn-Mg-Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al-Zn-Mg-Cu alloys [23] were quite ineffective on Al-Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al-Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy. PMID:21145675

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

2011-05-20

377

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Camadas de conversão ricas em Ce têm sido investigadas como possíveis substitutas às camadas de cromo na proteção contra a corrosão de ligas de alumínio. Neste trabalho a microestrutura e o comportamento eletroquímico da liga de alumínio 2024 com e sem camada de conversão de Ce foram investigados ut [...] ilizando MEV-EDS e EIE. Resultados de EDS mostraram que a presença de partículas de Cu depositadas sobre a superfície da liga estimula a formação da camada de conversão aumentando a intensidade dos picos de Ce no espectro EDS. Os experimentos de EIE mostraram que a presença da camada de conversão aumenta o valor da impedância, e que a evolução das características da camada pode ser seguida pelas mudanças que ocorrem no ângulo de fases em alta freqüência. As curvas potentiodinâmicas mostraram que a proteção conferida pela camada de conversão deve-se ao bloqueio da reação de redução do oxigênio. Abstract in english 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-ED [...] X 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.

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

2003-08-01

378

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Camadas de conversão ricas em Ce têm sido investigadas como possíveis substitutas às camadas de cromo na proteção contra a corrosão de ligas de alumínio. Neste trabalho a microestrutura e o comportamento eletroquímico da liga de alumínio 2024 com e sem camada de conversão de Ce foram investigados ut [...] ilizando MEV-EDS e EIE. Resultados de EDS mostraram que a presença de partículas de Cu depositadas sobre a superfície da liga estimula a formação da camada de conversão aumentando a intensidade dos picos de Ce no espectro EDS. Os experimentos de EIE mostraram que a presença da camada de conversão aumenta o valor da impedância, e que a evolução das características da camada pode ser seguida pelas mudanças que ocorrem no ângulo de fases em alta freqüência. As curvas potentiodinâmicas mostraram que a proteção conferida pela camada de conversão deve-se ao bloqueio da reação de redução do oxigênio. Abstract in english 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-ED [...] X 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.

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

379

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

380

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

Directory of Open Access Journals (Sweden)

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

K. Ganesa Balamurugan

2012-01-01

 
 
 
 
381

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

382

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-01-15

383

The Interaction between Particles and Low Angle Boundaries during Recovering of Aluminium-Alumina Alloys  

DEFF Research Database (Denmark)

Certain quantitative and qualitative aspects both of subgrain growth and of the interaction between particles and low angle grain boundaries during recovery have been investigated in two aluminium alloys containing low volume fractions of small alumina particles. Quantitative data have been obtained which indicate the frequency of interaction between particles and low angle grain boundaries during recovery. This frequency is found to be considerably higher than would be expected on the basis of random interactions between boundaries and particles. Further, experimental evidence is presented which shows that there are a number of different categories of interaction between particles and low angle grain boundaries during recovery. Certain of these types of interaction event have previously been undocumented. Hence, it is shown that the full range of particle interactions with low angle boundaries during recovery involves effects in addition to those of simple Zener pinning of migrating boundaries. For the current alloys it is found that a determination of the limits to normal subgrain growth in terms of a modified Zener analysis produces an underestimate of the true extent of particle pinning. The discrepancies between the experimental and theoretical results can be rationalised in terms of the limited nature of the physical effects modelled in the Zener analysis.

Hansen, Niels

1981-01-01

384

Laser welding of aluminium alloys 5083 and 6082 under conduction regime  

Science.gov (United States)

In this work, samples of aluminium alloys 5083-T0 and 6082-T6 have been welded under conduction regime, using a high power diode laser. The influence of experimental variables, as the laser power and the linear welding rate, on the sizes and properties of the butt weld beads has been studied. In addition to measure the depths and widths of the weld beads, their microstructure, microhardness profile and corrosion resistance have been analysed. The results obtained allow one to define the experimental conditions leading to good quality butt welds with higher penetration than those published in the recent literature under conduction regime. Maximum penetration values of 3 and 2.3 mm were obtained for 5083 and 6082, respectively. Additionally, a simple mathematical expression relating the weld depth ( d) with the laser power ( P) and the processing rate ( v) has been proposed: d=(P-bb)/(av)-(ba)/a, being a, a', b and b' constant values for each alloy and under the employed experimental conditions. The values of these coefficients have been estimated from the fitting to the experimental depth values of 5083 and 6082 butt welds generated under conduction regime.

Sánchez-Amaya, J. M.; Delgado, T.; González-Rovira, L.; Botana, F. J.

2009-09-01

385

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

Directory of Open Access Journals (Sweden)

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

G. Venkatasubramanian

2013-03-01

386

Oxide growth on aluminium alloys in the presence of ammonium fluoborate  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1996-12-31

387

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

Science.gov (United States)

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

Faraji, M; Katgerman, L

2010-08-01

388

Aluminium phosphide as a eutectic grain nucleus in hypoeutectic Al-Si alloys.  

Science.gov (United States)

Aluminium phosphide (AlP) particles are often suggested to be the nucleation site for eutectic silicon in Al-Si alloys, since both the crystal structure and lattice parameter of AlP (crystal structure: cubic F43m; lattice parameter: 5.421 A) are close to that of silicon (cubic Fd3m, 5.431 A), and the melting point is higher than the Al-Si eutectic temperature. However, the crystallographic relationships between AlP particles and the surrounding eutectic silicon are seldom reported due to the difficulty in analysing the AlP particles, which react with water during sample preparation for polishing. In this study, the orientation relationships between AlP and Si are analysed by transmission electron microscopy using focused ion-beam milling for sample preparation to investigate the nucleation mechanism of eutectic silicon on AlP. The results show a clear and direct lattice relationship between centrally located AlP particles and the surrounding silicon in the hypoeutectic Al-Si alloy. PMID:15585468

Nogita, Kazuhiro; McDonald, Stuart D; Tsujimoto, Katsuhiro; Yasuda, Kazuhiro; Dahle, Arne K

2004-01-01

389

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

International Nuclear Information System (INIS)

Laser surface treatment has been recognised as a useful method for corrosion protection of surfaces as a result of improved microstructure/phase formation and compositions. In large area applications, overlapping of individual tracks corresponding to the width of the laser beam is often necessary. This involves re-melting and re-heating of a portion of the previous track and results in microstructural changes, such as precipitate coarsening and microsegregation, which may influence localised corrosion at the overlapped regions. The purpose of this work is to investigate the influence of overlapped regions on corrosion behaviour of laser-melted aluminium 2014-T6 alloy. Laser melting was carried out using a 3 kW CW Nd:YAG laser with a line beam profile. The microstructures of the central part and the overlapped region of the melt pool were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Pitting corrosion resistance was evaluated using potentiodynamic anodic polarisation in 1 M NaCl solution. The work revealed enhancement of the pitting potential by 170 mV compared with that of the untreated alloy, similar to that achieved by laser surface melting with a CO2 laser in a Gaussian mode. The line beam profile results in elimination of the planar front zones at the treated surface, but this benefit was offset by a coarser microstructure

390

Calculation and experimental evaluation of activation parameters of aluminium and vanadium base alloys during their irradiation by neutrons produced in fusion and fission reactors  

International Nuclear Information System (INIS)

Results of numerical calculations of the level and kinetics of induced radioactivity decay in hypothetically pure aluminium, titanium, vanadium and certain alloys on their basis for the spectra of fission and fusion reactors up to neutron fluences of 1027 m-2 are presented. It is ascertained that vanadium-titanium alloys are low activized radiation-resistant materials, meeting ecological requirements for induced radioactivity. They can be successfully used in the first wall of d-T thermonuclear fusion reactors. Alloys on the basis of aluminium-magnesium-scandium system are perspective for units and structures of fission reactors. It is also true of vanadium-titanium alloys

391

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

392

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

Directory of Open Access Journals (Sweden)

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.

Girisha.K.B1 ,

2014-06-01

393

Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754  

International Nuclear Information System (INIS)

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

394

A study of diffusion in binary aluminium base alloys by means of the scanning electron microscope  

International Nuclear Information System (INIS)

The diffusion of various types of solute atoms in an aluminium matrix has been studied. To explain the diffusional growth of prismatic dislocation loops in Al-Mg alloys, previous researchers proposed a mechanism based on the extraction of Mg atoms from the Al-Mg matrix to the free surface of the sample during annealing. An important object of this project was an attempt to furnish direct evidence for this proposed migration of Mg atoms to the surface during annealing. The basic theory of diffusion is summarised in chapters 1 to 3, while chapter 4 covers the applied techniques. The results (chapter 5) are based on a study of the diffusion of solute atoms in platelets of Al-5% Mg, Al-4,5% Zn, Al-3% Ag and Al-3% Ge for various plate thicknesses at various annealing temperatures, =times and =atmospheres. With the aid of the microanalysis facilities of the scanning electron microscope, the concentration of the solute atoms as a function of distance from the surface of the platelet has every time been determined. The loss of magnesium from the alloy, which has been confirmed by a series of experiments, depends on various factors. These factors are being discussed in detail on the basis of the observed concentration profiles. Since the obtained concentration profiles can also in principle be utilised to determine the diffusion coefficient, the appropriate formula has been developed for this purpose (chapter 5). It is also demonstrated how the mentioned formula simultaneously gives rise to a new method for the determination of the activation energy for diffusion. Valuable information concerning the relative values of the surface energy, grain boundary energy and interface energy between various phases has been obtained for the case of the Al-Ge alloy

395

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

DEFF Research Database (Denmark)

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.

Daviðsdóttir, Svava; Soyama, Juliano

2011-01-01

396

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

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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.

D. Kuc

2012-03-01

397

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

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Full Text Available 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 correlation with process parameters.

Sashikant Janardan Morey

2011-03-01

398

Effect of precipitation during quenching on the mechanical properties of the aluminium alloy 7010 in the W-temper  

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Residual stress magnitudes in quenched high-strength aluminium alloys determined by several researchers using a variety of techniques indicate values that far exceed the as measured yield strength of the material in the quenched condition. Some research has indicated that the high residual stress magnitudes in large forgings may partly occur as a result of precipitation during the quench. To investigate this theory, a novel Jominy end quench technique is used to determine the hardness of alum...

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

2004-01-01

399

ANALYSIS OF MECHANICAL STRENGTH OF DISSIMILAR ALUMINIUM ALLOYS AA7075 AND AA2024 IN FRICTION STIR WELDING USING TAGUCHI'S TECHNIQUE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with the experimental investigation of effects of geometrical parameters of friction stir welding of dissimilar Aluminium alloys and analysis of output responses such as tensile strength in the friction stir welding. Taguchi's Design of Experiment (DoE) is used to design the experimental array, based on which experiments were conducted. For four parameters and four levels of each parameter, L16Orthogonal array is selected. To evaluate the output quality characteristics Taguch...

Muruganandam, D.; Raguraman, D.; Sushil Lal Das

2013-01-01

400

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

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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...

Idusuyi, Nosa; Kareem, Buliamin; Oji, John O.

2011-01-01

 
 
 
 
401

High-temperature mechanical properties of aluminium alloys reinforced with titanium diboride (TiB2) particles  

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The physical and mechanical properties of metal matrix composites were improved by the addition of reinforcements. The mechanical properties of particulate-reinforced metal-matrix composites based on aluminium alloys (6061 and 7015) at high temperatures were studied. Titanium diboride (TiB2) particles were used as the reinforcement. All the composites were produced by hot extrusion. The tensile properties and fracture characteristics of these materials were investigated at room temperature an...

On?oro Lopez, Javier

2011-01-01

402

The evolution of electrochemical, microstructural, and mechanical properties of aluminium alloy 2024-T4 (D16AT) during fatigue cycling  

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Coupons of fuselage skin made from the aluminium alloy D16AT (the Russian equivalent of 2024-Ò4) were obtained from several Russian TU-154 passenger aircraft after different numbers of flight cycles and different lengths of operation. The coupons were subjected to electrochemical, microstructural, and mechanical testing with the aim of identifying any trends indicating fatigue damage accumulation and residual fatigue lifetime reduction during service. Alongside this investigation, laboratory...

Salimon, Sr; Salimon, Ai; Korsunsky, Am

2010-01-01

403

Study of Residual Stress Tensors in High-Speed Milled Specimens of Aluminium Alloys Using a Method of Indent Pairs  

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From data obtained using a method of indent pairs it was possible to analyse different residual stress states generated in high-speed milled specimens of AA 6082-T6 and AA 7075-T6 aluminium alloys. The present method integrates a special device of indentation into a universal measuring machine, allowing the introduction of elongated indents to significantly reduce the absolute error of measurement. Diverse protocols for operations of high-speed face milling allow us to compare residual stress...

Felipe Víctor Díaz; Bolmaro, C. A. Mammana A. P. M. Guidobono And R. E.

2010-01-01

404

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

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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...

Lacroix, Loi?c; Blanc, Christine; Pe?be?re, Nadine; Thompson, George; Tribollet, Bernard; Vivier, Vincent

2012-01-01

405

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

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

A. Nagel

2007-10-01

406

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)

407

Work-hardening rates during the steady-state creep of aluminium and alloys determined from stress-change tests  

International Nuclear Information System (INIS)

Work-hardening rates of aluminium and selected aluminium alloys during steady-state creep at 300 0C are determined from the instantaneous strains on sudden stress changes (increments and decrement). Alloys examined included Al-0.4% Li, Al-0.3% Li (in three different irradiation conditions), =Al-2.73At% Mg and Al-4.20At% Mg. Work hardening rates, h, varied from about 0.1 to about 1 times =Young's modulus, E. h/E decreases with increasing creep stress, ?. At a given value of ?, h/E is the lowest for polycrystalline aluminium and highest for the irradiated Al-0.3% Li alloys. Although the values for h/E are comparable to previously determined values for the creep of f.c.c., b.c.c. and h.c.p. metals, they are higher than strain-hardening rates determined from tensile tests. These differences are rationalized in terms of the dependence of work (strain) hardening on the strain rate. (author)

408

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

409

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

Energy Technology Data Exchange (ETDEWEB)

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.

Rao, K. Srinivasa [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)]. E-mail: arunaraok@yahoo.com; Reddy, G. Madhusudan [Defense Metallurgical Research Laboratory, Hyderabad 500258 (India); Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)

2005-08-25

410

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-07-01

411

Contribution to the grain refinement of hypoeutectic aluminium-silicon casting alloys: application of a new grain refiner and experience from practice; Beitrag zur Kornfeinung von untereutektischen Aluminium-Silicium-Gusslegierungen: Anwendung eines neuen Kornfeiners und Erfahrungen aus der Praxis  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the application of a master alloy on the basis of aluminium-titanium-boron, that is designed for hypoeutectic aluminium-silicon casting alloys. The efficiency of the grain refiner was measured using thermal analysis and sand and permanent mould casted samples. The grain size was measured using metallographic technique. In addition, casting trials using a spiral sand mould were carried out to estimate the influence on the flowing behaviour of the melt. To compare the results, a standard AlTi5B1 rod was used under the same test conditions. Finally, results from practice are shown. The grain refinement mechanism is discussed. (orig.)

Koch, H. [Aluminium Rheinfelden GmbH, Rheinfelden (Germany)

2000-10-01