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1

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

International Nuclear Information System (INIS)

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

2

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

International Nuclear Information System (INIS)

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

3

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

4

Quantitative analysis of texture evolution of cold-rolled direct-chill-cast and continuous-cast AA5052 and AA5182 aluminum alloys during isothermal annealing  

Science.gov (United States)

The as-received direct-chill-cast (DC) and continuous-cast (CC) AA5052 and AA5182 hot bands were preheated at 454 °C for 4 hours, followed by cold rolling to an 80 pct reduction in thickness. The texture evolution of these cold-rolled samples during isothermal annealing was investigated by X-ray diffraction. The variation in texture volume fractions with annealing time was quantitatively analyzed by using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. The differences in recrystallization textures between the AA5052 and AA5182 alloys and between the DC and CC alloys were compared. It was found that the AA5052 alloy possessed a stronger cube recrystallization texture than the AA5182 alloy for the DC and CC materials. The recrystallization textures of the AA5182 alloy were affected strongly by the annealing temperature. As the annealing temperature increased, the cube recrystallization texture strengthened, whereas the R texture weakened. The annealing temperature had little influence on the recrystallization textures of the AA5052 alloy. The DC AA5052 and 5182 alloys also exhibited stronger cube recrystallization textures than the corresponding CC alloys. For the DC and CC AA5052 alloys, the n value in the JMAK-type equation increased with an increase in the annealing temperature, while the n values varied only slightly with the annealing temperature for the DC and CC AA5182 alloys.

Zhao, Y. M.; Liu, W. C.; Morris, J. G.

2004-11-01

5

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

6

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

7

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

Energy Technology Data Exchange (ETDEWEB)

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 {beta}-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 {beta}-fiber, the copper component was the strongest, having the fastest evolution rate, and S the weakest, during hot rolling.

Zeng, Q. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Paul Anderson Tower, Lexington, KY 40506 (United States); Wen, X. [Center for Aluminum Technology, College of Engineering, University of Kentucky, 1505 Bull Lea Road, Lexington, KY 40511 (United States); Zhai, T. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Paul Anderson Tower, Lexington, KY 40506 (United States)], E-mail: tzhai@engr.uky.edu

2008-03-15

8

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

International Nuclear Information System (INIS)

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

9

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

10

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)

11

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

International Nuclear Information System (INIS)

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

12

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

Directory of Open Access Journals (Sweden)

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

Tiago Valdameri Capelari

2009-09-01

13

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

14

The influence of the hot-deformed state on the recrystallization of Al-2.5%Mg (AA5052)  

Energy Technology Data Exchange (ETDEWEB)

A recent development of X-ray peak profile analysis has been used to evaluate the dislocation density (i.e. the stored energy) in five different texture components of a hot deformed aluminium-2.5wt%magnesium alloy (AA5052). These results have then been linked to EBSD data acquired on partially recrystallized samples in order to clarify the relationships between grain orientation, stored energy and recrystallization behavior. (orig.)

Guiglionda, G. [Microstructures and Processing Dept., Ecole des Mines de Saint-Etienne, Saint-Etienne (France)]|[PECHINEY CRV, Voreppe (France); Borbely, A. [Inst. for General Physics, Eoetvoes Lorand Univ., Budapest (Hungary); Poizat, L. [PECHINEY CRV, Voreppe (France); Driver, J.H. [Microstructures and Processing Dept., Ecole des Mines de Saint-Etienne, Saint-Etienne (France)

2001-07-01

15

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

Energy Technology Data Exchange (ETDEWEB)

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

Narayanasamy, R. [Department of Production Engineering, National Institute of Technology, Tiruchirappalli - 620015, Tamilnadu (India); Ravindran, R. [Department of Mechanical Engineering, VLB Janakiammal College of Engineering and Technology, Coimbatore - 641042, Tamilnadu (India)], E-mail: mceravindran@yahoo.co.in; Manonmani, K. [Department of Mechanical Engineering, Government College of Technology, Coimbatore - 641013, Tamilnadu (India)], E-mail: manokmani@yahoo.co.in; Satheesh, J. [Department of Production Engineering, National Institute of Technology, Tiruchirappalli - 620015, Tamilnadu (India)

2009-05-15

16

Comparison of recrystallisation behaviour of AA5052 after hot deformation in reversed torsion and in compression/tension  

Energy Technology Data Exchange (ETDEWEB)

During industrial hot working operations, such as rolling, forging and extrusion, regions of the workpieces undergo a change in strain path. A significant effect of change in straining direction in tension/compression deformation, which is the simplest change in strain path, on microstructural evolution and subsequent recrystallisation behaviour of aluminium-magnesium alloys has been found in previous research. The present paper shows the experimental results on the effect of change in straining direction of shear deformation on the microstructural evolution and subsequent recrystallisation behaviour, in comparison with those after axisymmetric deformation. The shear deformation was carried out in a torsion testing machine and the axisymmetric deformation in a tension/compression testing machine using the same alloy. Experimental results show a significant effect of change in straining direction on subsequent recrystallisation behaviour of AA5052 in axisymmetric deformation, but not in torsion. The mechanism of this difference may be related to the different microband behaviour in the axisymmetric and shear deformations, i.e. a higher density of microbands in the former, or a different texture evolution. (orig.)

Zhu, Q.; Sellars, C.M. [Inst. for Microstructural and Mechanical Process Engineering, Univ. of Sheffield (United Kingdom)

2002-07-01

17

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

18

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)

19

The influence of grain orientation on recrystallization in hot-deformed Al-2.5%Mg (AA5052)  

Energy Technology Data Exchange (ETDEWEB)

The influence of grain orientation on the energy stored during hot deformation and subsequent annealing behavior has been studied in a commercial Al-2.5%Mg alloy (AA5052). After plane strain compression tests at 400 C, the as-deformed state was characterized in terms of crystallographic texture and stored energy. The dislocation densities and stored energies in five different texture components were determined as a function of strain using a recent development of X-ray peak profile analysis. After subsequent annealing, EBSD data acquired on large areas of partially recrystallized samples were then used to determine the recrystallized fraction and the individual texture component ratios within both the remaining deformed grains and the new recrystallized grains. It is shown that S and Cu orientations which possess the highest stored energies are preferentially consumed by the recrystallization. Furthermore, during recrystallization the Cube fraction increases by faster nucleation particularly at high strains. (orig.)

Guiglionda, G. [Ecole des Mines de Saint-Etienne, Centre SMS, Saint-Etienne (France); Pechiney Centre de Recherches de Voreppe (France); Borbely, A. [Inst. for General Physics, Budapest (Hungary); Driver, J. [Ecole des Mines de Saint-Etienne, Centre SMS, Saint-Etienne (France); Chenal, B. [Pechiney Centre de Recherches de Voreppe (France)

2002-07-01

20

Texture evolution of AA5052 during monotonic and reversed hot deformation and subsequent recrystallization  

Energy Technology Data Exchange (ETDEWEB)

During industrial thermomechanical processing such as forging, rolling and extrusion, local regions within the stock undergo different strain paths. A significant effect of a change in strain path on microstructural evolution and subsequent recrystallisation behaviour has been observed previously for several texture free Al-Mg alloys under conditions of hot deformation in tension/compression. The mechanism of the effect is related to the evolution of geometrically necessary dislocations including the evolution of microbands, which are heterogeneously distributed in deforming materials and depend upon the orientation of grains. This work is currently being extended to texture evolution during continuous and reversed deformation. The combined effects of strain path on dislocation substructures and on deformation texture determine the subsequent recrystallisation behaviour and recrystallisation texture, which in turn dominate deep drawing properties of sheets. The present paper shows the effect of a change in strain path on the evolution of texture during either simple shear or axisymmetric deformation of AA5052 and during annealing of the deformed materials. The experimental alloy has initial Goss and Cube texture components. The simple shear was carried out in a reversible torsion machine and axisymmetric deformation in a tension/compression-testing machine. Texture was examined both using an X-ray texture goniometer and by electron backscattered diffraction (EBSD) in a scanning electron microscope. The results show that the evolution of texture is different during monotonic and reversed shear deformation. After annealing to partially recrystallise, the difference of orientation distribution becomes more significant than in the specimens deformed in torsion. After annealing for a short time, where no recrystallisation can be found, the texture components are different from the partially recrystallised specimens. (orig.)

Zhu, Q.; Wynne, B.P.; Beynon, J.H.; Sellars, C.M. [Univ. of Sheffield, Inst. for Microstructural and Mechanical Process Engineering, Sheffield (United Kingdom)

2002-07-01

 
 
 
 
21

Friction surfacing of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Friction surfacing is a solid state joining process that has attracted much interest in the past decades. This technology allows joining dissimilar metallic materials while avoiding the brittle intermetallic formations, involving temperatures bellow melting point and producing like forged metal structures. Much research using different steels has been made but the same does not happen with aluminium alloys, specially using different aluminium alloys. Friction surface coatings using cons...

Pereira, Diogo Jorge O. A.

2012-01-01

22

Friction against superplastic aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The authors of the present paper report the effect of temperature, strain rate and normal pressure on measured coefficients of friction of aluminium alloys 7475 and 5083, representing superplastic alloys designed respectively for high strength and superior formability at temperatures and strain rates within and outside the conditions for superplastic behaviour, deforming variously against a hot die steel tool and an alumina-based high temperature cement tool in air and under nitrogen. It was found that conditions at the interface dictated by the nature of lubrication and atmosphere had little effect on the coefficient of Coulomb friction, which was essentially determined by the particular alloy and the physical structure and the surface finish of the tool surface. Significantly, the coefficient of friction increased approximately exponentially as normal stress decreased and increased essentially linearly with strain rate. The most remarkable feature was the steep minimum in the coefficient of friction at the superplastic forming temperature. (orig.)

Chen Zhiping [Dept. of Materials Engineering, Monash Univ., Clayton (Australia); Thomson, P.F. [Dept. of Materials Engineering, Monash Univ., Clayton (Australia)

1996-12-15

23

Recent developments in advanced aircraft aluminium alloys  

International Nuclear Information System (INIS)

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

24

Effect of hydrogen on aluminium and aluminium alloys: A review  

DEFF Research Database (Denmark)

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

Ambat, Rajan; Dwarakadasa, E.S.

1996-01-01

25

Early stages of fatigue damage in aluminium and aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper fatigue damage initiation is considered as both microcrack nucleation from microheterogeneities within fatigued material and microcrack growth over distances corresponding to the size of the microstructure. A brief review of the literature shows that, depending on fatigue conditions and microstructure three different types of nucleation sites exist in aluminium and aluminium alloys : slip bands, grain boundaries and brittle particles. In the last part of this paper tentative to ...

Fougeres, R.

1993-01-01

26

Aluminium effect on titanium alloys fracture mode  

International Nuclear Information System (INIS)

The effect of chemical composition and regimes of heat treatment on the character of fracture of alloys with ?- and (?+?)-structure has been investigated. Studies have been conducted on industrial and half-industrial VT9, VT8, VT22, VT15, VT30 alloys. It is stated as a result of metallographical analysis that grain size of all the investigated alloys after heat treatment slightly depends on alloy composition and it is determined mainly by heating temperature. As a result of complex investigation into surfaces of fracture and character of alloying element distribution near interfaces it is stated that aluminium is adsorbed on interphase and intergrain interfaces thus weakening them and it promotes intergrain (interphase) fracture of titanium alloys. Due to the fact that most of industrial titanium alloys contain essential quantity of aluminium a possibility of non-uniform distribution of aluminium atoms over phase cross section should be necessarily taken into account when chosing regimes of their heat treatment

27

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.)

28

Mechanical alloying of aluminium-lithium-magnesium alloy powders  

International Nuclear Information System (INIS)

The production of high-purity aluminium-lithium-magnesium alloy powders, by mechanical alloying through grinding in a vibratory mill under high vacuum at room temperature, is described in details. The source materials for the grinding mixture were: aluminium-lithium alloy powder obtained by thermal vacuum-dehydrogenization of AlLiH4 hydride; magnesium metal powder; and chemically deoxidized aluminium metal powder. The implications which arose from the high reactivity of the component elements are discussed, and the measures taken to overcome them are described. The procedures used for the chemical analysis and powder characterization are given. (orig.)

29

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

30

Roll casting of 5182 aluminium alloy  

Directory of Open Access Journals (Sweden)

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

T. Haga

2009-06-01

31

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

32

Aluminium effect on titanium alloys fracture mode  

Energy Technology Data Exchange (ETDEWEB)

The effect of chemical composition and regimes of heat treatment on the character of fracture of alloys with ..beta..- and (..cap alpha..+..beta..)-structure has been investigated. Studies have been conducted on industrial and half-industrial VT9, VT8, VT22, VT15, VT30 alloys. It is stated as a result of metallographical analysis that grain size of all the investigated alloys after heat treatment slightly depends on alloy composition and it is determined mainly by heating temperature. As a result of complex investigation into surfaces of fracture and character of alloying element distribution near interfaces it is stated that aluminium is adsorbed on interphase and intergrain interfaces thus weakening them and it promotes intergrain (interphase) fracture of titanium alloys. Due to the fact that most of industrial titanium alloys contain essential quantity of aluminium a possibility of non-uniform distribution of aluminium atoms over phase cross section should be necessarily taken into account when choosing regimes of their heat treatment.

Popov, A.A.; Anisimova, L.I. (UPI im. S.M. Kirova)

1984-01-01

33

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

34

Microstructure Development during Solidification of Aluminium Alloys:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This Thesis demonstrates studies on microstructure development during the solidification of aluminium alloys. New insights of structure development are presented here. Experimental techniques such as quenching and in-situ High-brilliance X-ray microscopy were utilized to study the microstructure evolution during solidification.

Ruvalcaba Jimenez, D. G.

2009-01-01

35

TEM microstructure investigations of aluminium alloys used for laser alloying  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Labisz, K.; Krupin?ski, M.; Tan?ski, T.

2012-01-01

36

Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys  

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Yuksel, Serkan

2013-01-01

37

Aluminium and its alloys welding  

International Nuclear Information System (INIS)

Pure aluminum and aluminum alloys are well established as engineering materials for a wide range of applications because they offer a combination of low weight, high strength, good corrosion resistance formability and weldability. Due to the characterizations of the aluminum and its alloys is that it has a great an affinity for oxygen, and it has high thermal conductivity can rapidly conduct heat away from the area of weld for those reasons, it is necessary to apply a stream of inert gas protect the weld pool and apply the heat much faster to the weld area to bring the aluminum to the welding temperature, therefore the TIG and MIG makes them the best suited for welding aluminum in production. In this paper will identifies the common weldable aluminum alloys and processes used (TIG and MIG), it also highlights the growth of aluminum as structural materials, giving applications and references to current standards to welding aluminum.(author)

38

Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

39

Precipitate strengthening of nanostructured aluminium alloy.  

Science.gov (United States)

Grain boundaries and precipitates are the major microstructural features influencing the mechanical properties of metals and alloys. Refinement of the grain size to the nanometre scale brings about a significant increase in the mechanical strength of the materials because of the increased number of grain boundaries which act as obstacles to sliding dislocations. A similar effect is obtained if nanoscale precipitates are uniformly distributed in coarse grained matrix. The development of nanograin sized alloys raises the important question of whether or not these two mechanisms are "additive" and precipitate strengthening is effective in nanostructured materials. In the reported work, hydrostatic extrusion (HE) was used to obtain nanostructured 7475 aluminium alloy. Nanosized precipitates were obtained by post-HE annealing. It was found that such annealing at the low temperatures (100 degrees C) results in a significant increase in the microhardness (HV0.2) and strength of the nanostructured 7475 aluminium alloy. These results are discussed in terms of the interplay between the precipitation and deformation of nanocrystalline metals. PMID:23421286

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

2012-11-01

40

The Mechanism of Dross Formation on Aluminium and Aluminium Magnesium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Impey, S. A.

1989-01-01

 
 
 
 
41

Yield point elongation in Al-Mg alloys  

Energy Technology Data Exchange (ETDEWEB)

To investigate the nature of the pinning point inducing yield point elongation in Al-Mg alloys, AA5052 and AA5182 alloys were quenched from 723 K and subjected to quench ageing experiments. In AA5052 alloy, yield point elongation was not developed at all ageing temperatures. In AA5182 alloys, yield point elongation was observed after ageing at temperatures between 348 and 673 K. Since pinning of dislocations thus occurred even at 673 K, it was strongly suggested that pinning points formed during such ageing process were quite stable. Tensile tests made at various temperatures on these alloys by varying strain rate revealed that pinning points formed in AA5182 alloy are much more unstable than those formed in AA5052 alloy. (orig.)

Inagaki, H. [Shonan Inst. of Technol., Fujisawashi (Japan); Komatsubara, T.

2000-07-01

42

Solidification microstructures of aluminium-uranium alloys  

International Nuclear Information System (INIS)

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

43

Deviatoric response of the aluminium alloy, 5083  

Science.gov (United States)

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

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

2009-06-01

44

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

45

Aluminium Alloy Cast Shell Development for Torpedoes  

Directory of Open Access Journals (Sweden)

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

Vijaya Singh

2005-01-01

46

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

47

Melt spun aluminium alloys for moulding optics  

Science.gov (United States)

Melt spinning is a rapid quenching process that makes it possible to create materials with a very fine microstructure. Due to this very fine microstructure the melt spinning process is an enabler for diamond turning optics and moulds without the need of post-polishing. Using diamond turning of melt spun aluminium one can achieve contact lenses and spectacles. One of the alloys that RSP produces is RSA-905. This alloy has a solid track record as a better and cheaper concept in the application of moulds for optical components such as contact lenses. The RSA-905 is a dispersion hardened amorphous-like alloy that keeps its properties when exposed to elevated temperatures (up to 380°C). This gives the material unique features for optics moulding applications. RSA-905 moulds are cheaper and better than traditional mould concepts such as copper or brass with or without NiP plating. In addition logistics can be simplified significantly: from typical weeks-months into days-week. Lifetime is typically in the range of 100.000 - 200.000 shots. For high volume production typically ranging from several 100.000 - several 1.000.000 shots, NiP plated steel moulds are typically used. By using an appropriate optical coating concept RSA-905 can be upgraded to a competitive alternative to steel in terms of price, performance and logistics. This paper presents some recent developments for improved mould performance of such concept. Hardness, wear resistance and adhesion are topics of interest and they can be applied by special coatings such as diamond-like carbon (DLC) and chromium nitride (CrN). These coatings make the aluminium alloy suitable for moulding mass production of small as well as larger optics, such as spectacle lenses.

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

2013-09-01

48

Local electrochemical behaviour of 7xxx aluminium alloys:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Andreatta, F.

2004-01-01

49

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

50

Effect of filtration on reoxidation proceses in aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available This article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experimental works pointed out, that using filtration media placed in gating system causes reoxidation of poured aluminium alloy. Main aim of our latest work was to validate our arguments, that filter in gating system can be considered as obstacle for continuous pouring, with help of computer simulations. This article is only a small part of our researches focused on reoxidation processes during filtration of aluminium alloys.

D. Bolibruchova

2010-01-01

51

Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate  

Directory of Open Access Journals (Sweden)

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

B. Bobic

2010-03-01

52

Quantitative analysis of aluminium alloys using SIMS  

International Nuclear Information System (INIS)

A quantitative method for analysis of aluminium alloys using secondary-ion mass spectroscopy has been tested. The sensitivity factor, Sx/Al, for several elements (?) was determined using homogenised Al materials. Also other Al alloys were analysed using almost identical instrumental conditions. It was found that since the materials investigated contained much Fe and Mg, they contributed with molecular interferences when measuring Ti and Ni. The results showed that while keeping constant the analytical parameters, it was possible to use sensitivity factors Sx/Al with a good accuracy for quantification of the elements which were mainly solved in the matrix. The results indicated that the metal was still slightly inhomogeneous in several elements even after annealing at 550 C for one week. Another important factor is that the emission spectrometer has a high relative standard deviation for the analysis below 5 wt.ppm. This resulted in variations in the calculated sensitivity factor for elements like Na and Ca determined for different materials. The new method was used for calculating concentration profiles of elements in Al materials as a function of the sputtering depth. Samples of alloy AA5182 were homogenised for one week at 5 different temperatures between 450 and 580 C. The solubility of K, Na, and B in Al was determined. They were of the order 0.2 wt.ppm Na, 0.3 wt.ppm B and 0.04 wt.ppm K at 550 C. (orig.)ig.)

53

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.

54

Examples of liquid metal embrittlement in industrial aluminium alloys  

International Nuclear Information System (INIS)

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

55

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.

56

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)

57

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.)

58

Cold rolling and lubricated wear of 5083 aluminium alloy  

International Nuclear Information System (INIS)

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

59

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

60

Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins  

Directory of Open Access Journals (Sweden)

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

Ivan Michalec

2013-01-01

 
 
 
 
61

Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ivan Michalec; Milan Marônek

2013-01-01

62

A study on the recycling of aluminium alloy 7075 scrap  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-01

63

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

International Nuclear Information System (INIS)

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

64

Creep rupture data for aluminium alloys. Pt. 3  

Energy Technology Data Exchange (ETDEWEB)

Creep rupture data have been evaluated for aluminium alloys. Data were collected from the open literature for AlMn, AlMg, AlMgSi, and AlZnMg alloys. Previously unpublished data were also supplied from Alusuisse-Lonza. (orig.)

Sandstroem, R. (Royal Inst. of Technology, Stockholm (Sweden))

1993-05-01

65

A comparative wear study on heat-treated aluminium-lithium alloy and pure aluminium  

Energy Technology Data Exchange (ETDEWEB)

Wear behaviour of solution-treated and aged aluminium-lithium alloy (2.5% Li, 2% Cu, 1% Mg and 0.15% Zr) was compared with that of pure aluminium. Wear tests were carried out in ambient air in a pin-on-disc type apparatus under dry sliding conditions using hardened steel disc as the counterbody. A normal load of 10 N and a linear speed of 0.98 m s{sup -1} were used during the tests. Microscopic investigation, microhardness measurement on the subsurface of wear scars on pins, X-ray diffraction study and morphological examination of wear debris were done to elucidate wear mechanism. It has been found that the wear resistance of the aluminium-lithium alloy is about two and half times higher than that of pure aluminium. Subsurface deformation, delamination, etc. have been found during the wear of the aluminium-lithium alloy, while severe adhesive wear has been identified as the main mechanism in pure aluminium. (orig.) 11 refs.

Aminul Islam, M.; Haseeb, A.S.M.A. [Bangladesh Univ. of Engineering and Technology, Dacca (Bangladesh). Dept. of Metallurgical Engineering

1999-08-15

66

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

67

Research of Properties of Sprayed Coatings on the Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 catho...

Raimonda Lukauskait?; Denis Kovaliov; Olegas ?ernaš?jus

2014-01-01

68

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

69

Stress corrosion cracking of silver-bombarded aluminium alloys  

International Nuclear Information System (INIS)

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

70

Tribological rutile-TiO 2 coating on aluminium alloy  

Science.gov (United States)

The present paper describes a novel process developed to improve the tribological properties of aluminium alloys. The process involves the fabrication of a rutile-type TiO 2 coating on an aluminium alloy by the combination of sputter-deposition of a pure titanium coating on the substrate and subsequent thermal oxidation. The resultant coating has a layered structure, comprising a rutile-TiO 2 layer at the top, an oxygen and nitrogen dissolved ?-Ti layer in the middle and a titanium-aluminide layer in the interfacial region. Such a hybrid coating system has good adhesion with the substrate, can significantly enhance the surface hardness and tribological properties of the aluminium alloy in terms of much reduced friction coefficient and increased wear resistance.

Sun, Y.

2004-06-01

71

Residual stress in 7449 aluminium alloy forgings  

International Nuclear Information System (INIS)

The through thickness residual stress distributions within three 120 mm thick rectilinear forgings, made from the high strength aluminium alloy 7449 have been measured using both neutron diffraction and deep hole drilling. Neutron diffraction measurements were made on two instruments, one using a pulsed spallation neutron source, the other a steady state reactor source. Heat treatment of the forgings included a rapid quench into cold water and it was the residual stresses arising from this step that were initially measured. Neutron diffraction measurements indicated large magnitude (>250 MPa) tensile residual stresses in the centre of an as quenched forging, balanced by surface regions stressed in compression (<-200 MPa). Sufficient measurements were made to permit the description of the residual stress distribution using area maps. Two forgings were stress relieved by cold compression immediately after quenching. The degree of plastic strain was either 2.5% or 4%, and was applied by a single application of force in the short transverse direction. Cold compressed forgings were found to have far lower residual stress when compared to the as quenched condition. The amount of cold compression was found to cause an insignificant difference in the final residual stress distribution. The neutron diffraction results are compared to measurements made by deep hole drilling and a new incremental variation of the technique. The deep hole was drilled through the centre of the for was drilled through the centre of the forgings in the short transverse direction. Multiple neutron diffraction measurements were also made on the extracted cores from the deep hole measurements to assess the variation of the unstrained lattice parameter through the thickness of the forgings.

72

Natural Honey as Corrosion Resistant for Aluminium Alloy  

Science.gov (United States)

The corrosion behaviour of AA6061 aluminium alloy in tropical seawater was investigated using weight loss measurement and electrochemical polarization technique. The electrochemical measurements showed that the presence of natural honey as corrosion resistant significantly decrease the corrosion current densities (icorr) and corrosion rates. It was observed that the inhibition efficiencies increased with the increasing concentrations of the resistant. Potentiodyanamic curves suggested that natural honey suppressed both cathodic and anodic processes. A good fit to Langmuir adsorption isotherm was obtained between the degree of surface coverage and the concentration of natural honey. It can be concluded that natural honey is an excellent corrosion resistant for aluminium alloy immersed in tropical seawater.

Rosliza, R.; Senin, H. B.; Muzathik, A. M.; Wan Nik, W. B.

2009-07-01

73

On inhibition of local dissolution of aluminium alloys  

International Nuclear Information System (INIS)

A possibility to use the principles of free energy linearity and polylinearity for the efficiency forcasting and mechanism study of the D16T aluminium alloy protection by sodium orthoarylcarboxylates from local dissolution is stUdied. For the purpose the aluminium alloy is subjected to anodic polarization in borate buffer solutions (pH 8.08) containing different concentrations of corrosive anions (Cl-, Br-, I-, CNS-, CCl3COO-). Dependences of the inhibition effect of orthoarylcarboxylates on the induction constants of substituent are studied. It is shown that using the electron characteristics of chemical compounds it is possible to forecast quantitatively the protective properties of organic inhibitors

74

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

75

FACTORS INFLUENCING THE ENVIRONMENTAL BEHAVIOUR OF ALUMINIUM-LITHIUM ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Gray, A.

1987-01-01

76

Image analysis used for aluminium alloy microstructure investigation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: In this work the metallographic microstructure analysis of the investigated AlSi7Cu3Mg aluminium cast alloy was performed for samples cooled with different cooling rate settings. The preformed investigations are subjected to the analysis of cooling rate influence on the phase morphology.Design/methodology/approach: The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The influence of the cooling rate on the alloy micros...

Krupin?ski, M.; Labisz, K.; Dobrzan?ski, L. A.; Rdzawski, Z.

2010-01-01

77

Rapid spectrophotometric determination of yttrium in aluminium alloys  

International Nuclear Information System (INIS)

An easy and rapid determination of yttrium with chlorphosphonazo 3 in aluminium alloys is considered. The effect of base is removed by masking with fluoride ion. Y can be determined within the concentration range n-n x 0.01%. 4 refs., 1 fig., 2 tabs

78

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

79

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

80

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

 
 
 
 
81

Aluminium alloys doped with lithium, copper and magnesium  

International Nuclear Information System (INIS)

Phase composition of M-Li-Cu-Mg alloys in region aluminium reach is studied by microstructural, micro- and X-ray diffraction analysis. Binary phases ?, AlLi and phases of ternary systems: Al-Cu-Li, Al-Cu-Mg, Al-Li-Mg are at equilibrium with aluminium solid solution haw compounds in the system region studied are not detected. Cross sections of isothermal tetrahedron at 400 deg C with constant copper content (1,5 and 2,8%) are plotted

82

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

83

Recycling of aluminium scrap for secondary Al-Si alloys.  

Science.gov (United States)

An increasing amount of recycled aluminium is going into the production of aluminium alloy used for automotive applications. In these applications, it is necessary to control and remove alloy impurities and inclusions. Cleaning and fluxing processes are widely used during processing of the alloys for removal of inclusions, hydrogen and excess of magnesium. These processes use salt fluxes based in the system NaCl-KCl, injection of chlorine or mixture of chlorine with an inert gas. The new systems include a graphite wand and a circulation device to force convection in the melt and permit the bubbling and dispersion of reactive and cleaning agents. This paper discusses the recycling of aluminium alloys in rotary and reverberatory industrial furnaces. It focuses on the removal of magnesium during the melting process. In rotary furnaces, the magnesium lost is mainly due to the oxidation process at high temperatures. The magnesium removal is carried out by the reaction between chlorine and magnesium, with its efficiency associated to kinetic factors such as concentration of magnesium, mixing, and temperature. These factors are also related to emissions generated during the demagging process. Improvements in the metallic yield can be reached in rotary furnaces if the process starts with a proper salt, with limits of addition, and avoiding long holding times. To improve throughput in reverberatories, start the charging with high magnesium content material and inject chlorine gas if the molten metal is at the right temperature. Removal of magnesium through modern technologies can be efficiently performed to prevent environmental problems. PMID:20837560

Velasco, Eulogio; Nino, Jose

2011-07-01

84

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

85

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

86

Car body alloys and methods of corrosion protection: aluminium sheet  

Energy Technology Data Exchange (ETDEWEB)

The aluminium industry supplies various car body sheet qualities tailor-made to meet the requirements of the car producers. The most important alloy types are AlMgSi (free from stretcher-strain markings after forming and hence suited for outer skin) and AlMg (for interior use). In addition to the significant weight savings it is its long service life which makes aluminium an attractive alternative to steel sheets. A prerequisite for good corrosion resistance is a surface treatment optimised for aluminium. This includes the creation of a phosphate surface layer to allow lacquer coating together with steel and galvanized steel on existing lines. The Accelerated Outdoor Exposure Test (VDA 621-414) proved to be the only static corrosion test method suitable for assessing the resistance level of the final lacquered car body. In addition to the proper selection of alloy and surface finishing technique it is important that some aluminium-specific precautions are taken during manufacture if the full long service potential of the material is to be realized. (orig.)

Textor, M. [Alusuisse-Lonza Services AG, Neuhausen (Switzerland); Nema, P. [Alusuisse-Lonza Services AG, Neuhausen (Switzerland); Timm, J. [Alusuisse-Lonza Services AG, Neuhausen (Switzerland)

1995-06-01

87

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.

88

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

89

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

International Nuclear Information System (INIS)

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 40-1000C 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 pure Al. The amount of gas accumulation at grain boundaries was found to depend on gas generation rate, alloying and cold-work microstructure. (orig.)

90

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

91

Corrosion fatigue of cast aluminium- and cast magnesium alloys; Korrosionsermuedung von Aluminium- und Magnesium-Gusslegierungen  

Energy Technology Data Exchange (ETDEWEB)

The fatigue properties of the aluminium cast alloys AlSi7Mg and AlSi10Mg, magnesium high pressure die-cast AZ91 hp and AM60 hp, as well as low-pressure permanent mould casting AZ91 hp were determined at numbers of cycles to failure between 10{sup 5} and 10{sup 9} in ambient air and in saltwater spray. The investigations were performed at constant amplitudes and in addition at varying load amplitudes for aluminium cast alloy AlSi10Mg and low-pressure permanent mould casting AZ91 hp with a high-frequency testing facility (20 kHz ultrasound). The SN-curves of the aluminium cast alloys and of the magnesium low-pressure permanent mould casting are steeper in corrosive environment than in laboratory air. No endurance limit could be detected up to 10{sup 9} cycles in both environments. The magnesium high pressure die-cast alloys do not have an endurance limit in saltwater spray, whereas an endurance limit could be detected in laboratory air. The life time curves for in-service loading conditions are about parallel to the SN-curves for ambient air, but steeper for corrosive environment. The reason for the reduced fatigue properties in corrosive environment are accelerated crack initiation and higher crack propagation rates. Material defects may lead to a large scatter of the fatigue data for testing in air as well as in saltwater spray. Corrosion pits are formed on the surface of both light-weight alloys at higher number of cycles. They become crack initiation sites. (orig.) 10 refs.

Mayer, H.; Papakyriacou, M.; Stanzl-Tschegg, S.; Zettl, B. [Univ. fuer Bodenkultur, Vienna (Austria). Inst. fuer Meteorol. und Phys.; Tschegg, E. [Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik; Lipowsky, H.; Roesch, R.; Stich, A. [Audi AG, Ingolstadt (Germany)

1999-02-01

92

Deviatoric response of an armour-grade aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Appleby-thomas, G. J.; Hazell, P. J.; Millett, J.; Bourne, Neil K.

2009-01-01

93

Characterization of oxyde films and conversion layers on aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 charac...

Laet, J.; Goeminne, G.; Terryn, H.; Vereecken, J.

1993-01-01

94

TEM microstructure investigations of aluminium alloys used as coating substrate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Tan?ski, T.; Labisz, K.; Dobrzan?ski, L. A.; Wis?niowski, M.; Matysiak, W.

2013-01-01

95

Fatigue behavior of GMAW welded Aluminium alloy AA7020  

International Nuclear Information System (INIS)

The aim of this investigation is to evaluate the influence on the fatigue behavior by the finishing of the bulge in a welded aluminium-zinc-magnesium alloy AA7020. It was determined that total or partial elimination of the bulge has very little influence on its behavior, giving a very similar result on both cases, where one is better than the other by only 3%. (Author) 20 refs

96

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.

97

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

98

Laser surface alloying of aluminium-transition metal alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 proc...

Almeida, A.; Vilar, R.

1998-01-01

99

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

100

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

 
 
 
 
101

Chip arrangement in the dry cutting of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The aim of the research is make a first analysis of the chip formed in the dry turning process of AA2024 (Al-Cu) and AA7050 (Al-Zn) aluminium alloys.Design/methodology/approach: The methodology has consisted of proving a series of parameters combinations: feed rate, f, cutting speed, v, and depth of cut, d, and of analysing the different types of chip appeared during each one of them.Findings: A single classification, specific for the studied alloys, has been proposed. This classific...

Rubio, E. M.; Camacho, A. M.; Sa?nchez-sola, J. M.; Marcos, M.

2006-01-01

102

RTR spent fuel reprocessing: Nitric acid dissolution of aluminium alloys  

International Nuclear Information System (INIS)

The process proposed by COGEMA for reprocessing spent fuel from research reactors is based on an initial step in which the fuel plates are completely dissolved in nitric acid. The CEA therefore initially examined the dissolution of aluminium, the material used for the fuel cladding. Unirradiated samples of the various aluminium alloys used by CERCA for the fabrication of these assemblies were dissolved experimentally in hot nitric acid. The study focused on AG3NE alloy, for which the dissolution rate was measured at temperatures ranging from 700C to the boiling point (?1100C) and for solution acidity values from 3 to 9 N. The dissolution kinetics of the other alloys were then measured at the boiling temperature and [HNO3]0 = 9 N. The alloy composition was found to have a significant effect on the results. The effects of the reactor residence time on the materials were assessed by measuring the dissolution rates of samples maintained for 200 hours in demineralized water at 900C. For some alloys this treatment resulted in a significant increase in the initial rate, which then gradually diminished. The rate increase can be attributed to the increased material surface area in contact with the solution due to surface corrosion. (author)

103

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, thwth 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)

104

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

105

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

106

Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite  

Science.gov (United States)

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.

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

2011-01-01

107

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.

108

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

Science.gov (United States)

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

Reed, R. P.

1972-01-01

109

Positron annihilation study of effect of aluminium on iron-based amorphous alloys  

International Nuclear Information System (INIS)

Seven Fe-based amorphous alloys have been studied by Doppler broadening and lifetime techniques of the positron annihilation. It is shown that the parameters of positron annihilation in the Fe-based amorphous alloys containing more aluminium are larger than those in the alloys with less aluminium, which means that the existence of element Al in Fe-based amorphous alloys results in more vacancy-like defects

110

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

Directory of Open Access Journals (Sweden)

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

Prabhkiran Kaur

2014-08-01

111

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

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

Bunkholt, Sindre

2013-01-01

112

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

113

Chip arrangement in the dry cutting of aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the research is make a first analysis of the chip formed in the dry turning process of AA2024 (Al-Cu and AA7050 (Al-Zn aluminium alloys.Design/methodology/approach: The methodology has consisted of proving a series of parameters combinations: feed rate, f, cutting speed, v, and depth of cut, d, and of analysing the different types of chip appeared during each one of them.Findings: A single classification, specific for the studied alloys, has been proposed. This classification has been built in a similar way to those recorded in ISO 3685 standards. As a result, it has been able to realise that a direct correspondence with that standards does not exist. Besides, the relationship between chip arrangement and workpiece surface finish has been studied through the comparison between chip form and Ra parameter for different cutting conditions.Research limitations/implications: A possible future work is the development of a general standard, like ISO 3685, for the rest of the aluminium alloys.Practical implications: The relationship found between chip arrangement and workpiece surface finish has an important practical implication since it allows selecting the best cutting condition combination from the points of view both the security and the economy for the established requirements in each case.Originality/value: The paper is original since the bibliographical review has allowed testing that, although works about these themes exist, none approaches the problem like it has been made in this work.

E.M. Rubio

2006-04-01

114

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route  

International Nuclear Information System (INIS)

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

115

Deviatoric Response of AN Armour-Grade Aluminium Alloy  

Science.gov (United States)

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

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

2009-12-01

116

Anode-spark layers on aluminium alloys in borate electrolytes  

International Nuclear Information System (INIS)

Influence of pH value of borate electrolytes on parameters of formation, thickness, electric strength, chemical and phase composition of anode-spark layers on aluminium alloy was studied by the methods of elementary and X-ray phase analyses. It was ascertained that the films containing up to 10 at.% of boron and carbon oxides were concentrated near the surface of anode layers. At a constant boron concentration increase in electrolyte pH from 6.5 to 10.2 results in growth of the coatings thickness and reduction of electric strength

117

Electrochemical protection of aluminium and its alloys in seawater  

International Nuclear Information System (INIS)

Cathode-anode protection of aluminium and its alloys (AMsub(ts) AMsub(r)-6) in seawater is developed for elimination of cathode and anode corrosion. After cathode protection switching on and after strong alkalization (which conditions cathode corrosion) cathode protection is being switched off and anode one is being switched on. After neutralization of near-cathode water layer anode protection is being switched off and cathode one is being switched on etc. Presented is a principle diagram providing automatic switching of protective potential at cathode-anode protection. It is shown that it is possible to achieve four-fold decrease of corrosion with the helppof such protection

118

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)

119

Helium atoms behaviours in aluminium and its alloys  

International Nuclear Information System (INIS)

The aluminium and its alloys specimens AMg and AMg(Sc) irradiated to the different doses by the low-energy helium ions from the glow discharge plasma at the temperature of ? 3500C were investigated by the internal friction method, thermodesorption method, optical and transmission electron microscopy method. The dose dependences of the grain boundary maximum height changing were made. The helium binding energy with the grain-boundary traps was calculated. The helium concentration in the samples corresponded to the grain boundaries adsorption saturation and investigated materials inclination to swelling were estimated. 11 refs.; 3 figs.; 1 tab. (author)

120

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

 
 
 
 
121

Determination of phosphorus in hypereutectic aluminium-silicon alloys.  

Science.gov (United States)

A reproducible method is described for determination of small amounts of phosphorus (from 0.0005% to 0.02%) in hypereutectic aluminium-silicon complex alloys. The method permits the separate determination of phosphorus in acid-soluble and acid-insoluble fractions. Phosphomolybdate is extracted with n-butanol-chloroform solvent mixture and back-extracted with a btannous chloride reducing solution. The phosphorus content of a sample cut into small pieces decreases during storage; loss of phosphorus is negligible on acid dissolution under oxidizing conditions. PMID:18961077

Mukai, K

1972-04-01

122

The fracture of boron fibre-reinforced 6061 aluminium alloy  

Science.gov (United States)

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

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

1979-01-01

123

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

124

Precipitation kinetics of Si in aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-05-15

125

Electromagnetic forming of aluminium alloy sheet  

Science.gov (United States)

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

Oliveira, D. A.; Worswick, M.

2003-09-01

126

High rate constitutive modeling of aluminium alloy tube  

Science.gov (United States)

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

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

2006-08-01

127

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

128

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

129

Image analysis used for aluminium alloy microstructure investigation  

Directory of Open Access Journals (Sweden)

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

M. Krupi?ski

2010-09-01

130

Contradictory effect of chromate inhibitor on corrosive wear of aluminium alloy  

International Nuclear Information System (INIS)

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

131

Preparation of aluminium lithium 8090 alloy and effect of ageing on microstructure and hardness  

International Nuclear Information System (INIS)

Aluminium-Lithium alloys are making way to replace the conventional alloy in aircraft industry due to their reduced density and strength (one such replacement is Al-Li 8090). In the present work preparation of AA8090 alloy and effect of ageing on its hardness and microstructure is discussed. The alloy was prepared by melting pure aluminium and other alloying addition in vacuum induction furnace under inert atmosphere of argon. The alloy was homogenized at 550 deg. C and aged in temperature range of 190 to 230 deg. C. The maximum hardness of HV 130 was obtained by ageing at 210 deg. C for 24 hours. (author)

132

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

International Nuclear Information System (INIS)

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

133

Superplastic behaviour of a rapidly solidified 7475 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

To investigate possible superplastic behaviour, tensile tests were performed on conventionally cast and extruded aluminium alloy AA 7475, rapidly solidified and extruded AA 7475, and rapidly solidified and extruded AA 7475, which contained 0.45 wt.% Zr. The rapid solidification process used was melt spinning. The extruded materials were not subjected to thermomechanical processing, but the effects of various simple heat treatments were investigated. The rapidly solidified Zr-containing alloy had the smallest grain size (1 {mu}m), the highest elongation, and the lowest flow stress. Heating at 300 C for 4 h improved the elongation and lowered the flow stress for this alloy. After this treatment, an elongation of 390% was observed at 450 C and a strain rate of 8x10{sup -2} s{sup -1}. The strain rate sensitivity exponent was 0.58. It was concluded that the rapidly solidified Zr-containing alloy was superplastic and that a full thermomechanical treatment after rapid solidification is not needed to achieve such an effect. ((orig.))

Strijbos, G.H. [Technische Univ. Delft (Netherlands). Lab. of Materials Science; Kool, W.H. [Technische Univ. Delft (Netherlands). Lab. of Materials Science

1995-05-01

134

Characterization and structure of precipitates in 6xxx Aluminium Alloys  

Science.gov (United States)

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.

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

2012-07-01

135

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

136

High effective organic corrosion inhibitors for 2024 aluminium alloy  

International Nuclear Information System (INIS)

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

137

Creep rupture data for aluminium alloys. Pt. 1  

Energy Technology Data Exchange (ETDEWEB)

Creep rupture data have been evaluated for aluminium alloys. Data were collected from the open literature for AlMn, AlMg, AlMgSi, and AlZnMg alloys. Previously unpublished data were also supplied from Alusuisse-Lonza. In order to obtain extrapolated creep rupture strength values, the data were analysed with the help of four time-temperature parameters (TTP): Larson-Miller, Orr-Sherby-Dorn, Manson-Succop and Sud-Aviation. For each alloy and TTP a master curve was generated, which was used to compute the extrapolated values. The final result was taken as the average between values from the different master curves. Only these TTP's which showed a correct physical behaviour for the individual alloy were included. The error in the extrapolated values was taken as the maximum difference between the TTP methods. The accuracy of the results was also checked by comparison to independent data not included in the analysis. The critical temperature where creep becomes the design controlling property was assessed. The derived creep values are available in the database 'Aluselect'. (orig.).

Sandstroem, R. (Applied Materials Technology, Royal Inst. of Tech., Stockholm (Sweden))

1993-03-01

138

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The main aim of this work is to investigate two types of intermetallics TiAl and Ti3Al as reinforcement and their influence on selected properties and microstructure of aluminium matrix composites.Design/methodology/approach: Aluminium matrix composites were produced employing the atomised aluminium alloy AA6061 as metal matrix, when as reinforcement TiAl and Ti3Al intermetallics particles were used. The powders were cold pressed and then hot extruded. To evaluate the effect of mecha...

Adamiak, M.

2005-01-01

139

Electrodeposition of aluminium film on P90 Li-Al alloy as protective coating against corrosion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we report on the electrodeposition of thin aluminium layers on P90 lithium–aluminium alloy at room temperature from a chloroaluminate ionic liquid (1-butyl-3-methyl imidazolium heptachloroaluminate [BMIm]Al2Cl7). We found that the treatment of the P90 sample's surface is a key point to obtain good quality coatings. On freshly mechanically polished surfaces, thin (about 24 µm), homogeneous and dense aluminium layers were obtained at 10 µm h? 1 deposition r...

Bardi, U.; Caporali, S.; Craig, M.; Giorgetti, A.; Perissi, I.; Nicholls, J. R.

2009-01-01

140

Analytic and experimental study for light alloy aluminium panels under compression  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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/...

Fayza, A.; Zghal, A.; Bayraktar, E.

2007-01-01

 
 
 
 
141

High effective organic corrosion inhibitors for 2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

Lamaka, S.V. [University of Aveiro, CICECO, Department of Ceramics and Glass Engineering, 3810-193 Aveiro (Portugal)]. E-mail: sviatlana.lamaka@cv.ua.pt; Zheludkevich, M.L. [University of Aveiro, CICECO, Department of Ceramics and Glass Engineering, 3810-193 Aveiro (Portugal); Yasakau, K.A. [University of Aveiro, CICECO, Department of Ceramics and Glass Engineering, 3810-193 Aveiro (Portugal); Montemor, M.F. [Instituto Superior Tecnico, ICEMS, Department of Chemical Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Ferreira, M.G.S. [University of Aveiro, CICECO, Department of Ceramics and Glass Engineering, 3810-193 Aveiro (Portugal); Instituto Superior Tecnico, ICEMS, Department of Chemical Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

2007-09-15

142

High strain rate superplasticity in three contrasting fine grained aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The superplastic properties and microstructures of three contrasting fine grained aluminium alloys were investigated. These included (i) a powder metallurgy MMC, (ii) a severely deformed spray cast alloy, and (iii) the Zn-22%Al eutectoid alloy. The results showed some differences in the details of behaviour between the alloys. One of these was the presence of true work hardening, associated with dislocation activity, in the MMC, and its absence in the microduplex Zn-Al eutectoid alloy. In add...

Todd, Ri; Kim, Js; Zahid, Gh; Prangnell, Pb

2000-01-01

143

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

144

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

Directory of Open Access Journals (Sweden)

Full Text Available The usage of powder metallurgy aluminium compacts in lieu of ferrous components in automotives helps to lower vehicle weight. The major drawback in the commercially available press sintered aluminium alloy is porosity which is mainly dependent on the powder metallurgical process parameters such as compaction pressure, sintering temperature and cooling rate after sintering. In this paper the effect of particle size and furnace controlled cooling after sintering on porosity level and micro hardness of an elemental 6061 aluminium alloy has been investigated. Aluminium particle sizes of 20 µm and 150 µm were used. The elemental 6061 aluminium alloy powders are warm compacted at 175 MPa. After sintering for about one hour at 600°C, the aluminium compacts were furnace cooled at the rate of 1°C /min to different temperatures of 500°C, 400°C, 300°C and 200?C. When the cooling temperature after sintering inside the furnace is effected at various temperatures from 600°C to 200°C, for a precipitate hardened aluminium compacts with aluminium particle size of 20 µm, the porosity level reduced by 26% and that for aluminium particle size of 150µm, the porosity level reduced by 23%. Marked improvement in micro hardness value is also observed correspondingly.

S. Solay Anand

2011-07-01

145

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

146

Precipitation kinetics in a severely plastically deformed 7075 aluminium alloy  

International Nuclear Information System (INIS)

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

147

Simulation of microstructure and liquation cracking in 7017 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Welding in a 7000 series aluminium alloy can lead to the development of a white zone microstructure and liquation cracking in the heat affected zone adjacent to the fusion boundary. A Gleeble 1500 thermomechanical system has been used to study the conditions associated with damage development. A range of simulations has been carried out covering thermal and thermomechanical conditions typically encountered during weld manufacture. Results show that both the white zone microstructure and liquation cracking can be simulated at a sufficient scale to permit full characterisation in laboratory testpieces. Data analysis has defined and mapped the stress and temperature conditions leading to crack initiation. This evaluation demonstrates that the susceptibility for cracking is minimised by increasing the cooling rate following weld manufacture. (orig.)

Lu, Z.-J. [Wales Univ., Swansea (United Kingdom). Dept. of Mater. Eng.; Evans, W.J. [IRC, Department of Materials Engineering, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP (United Kingdom); Parker, J.D. [Wales Univ., Swansea (United Kingdom). Dept. of Mater. Eng.; Birley, S. [Defence Research Agency, Chobham Lane, Chertsey, Surrey, KT16 OEE (United Kingdom)

1996-12-15

148

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.)

149

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

150

Large rolled plates with Ni complexed copper-aluminium alloys for power plants condensers  

International Nuclear Information System (INIS)

The article stresses the value of cupro-aluminium containing Ni for the fabrication of large plates for the condensers of coastal nuclear power plants. The properties of these alloys are presented: corrosion resistance, mechanical properties, rolling, welding, drilling

151

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.)

152

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.)

153

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Fourmeau, Marion

2014-01-01

154

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

155

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

156

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

Energy Technology Data Exchange (ETDEWEB)

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., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Heroon Polytechneiou 9, Zografos 15780, Athens (Greece); Georgiou, E.P. [Laboratory of Physical Metallurgy, National Technical University of Athens, Heroon Polytechneiou 9, Zografos 15780, Athens (Greece)

2009-04-15

157

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

158

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.

159

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

160

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)

 
 
 
 
161

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

International Nuclear Information System (INIS)

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

162

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 differenti...

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

2007-01-01

163

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Omran, Abdel-nasser M.

2014-01-01

164

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

International Nuclear Information System (INIS)

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

165

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

International Nuclear Information System (INIS)

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

166

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

International Nuclear Information System (INIS)

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

167

Interaction between aluminium alloy and coolant under primary circuit condition at nuclear district heating plants  

International Nuclear Information System (INIS)

Aluminium alloy-water interaction under primary circuit condition at nuclear district heating plants (?-radiation from 60Co, the temperature of 473 K) is studied. It is stated that the alloy promotes formation of great hydrogen quantities. Corrosion rate is reduced by half under radiation effect (the test time is 200 h). The aluminium alloy inhibits radiation-induced formation of hydrogen peroxide. The main indices of water-chemical regime (corrosion product concentrations, electric conductivity, oxidation potential on platinum electrode, pH value etc.) nonmonotonically vary during corrosion test. Correlation interrelations of the indices in the form of mathematical equations are detected

168

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

169

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

170

Embedding of SBR feed sewage sludge in aluminium alloys  

International Nuclear Information System (INIS)

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

171

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

Energy Technology Data Exchange (ETDEWEB)

Variations in solute element distribution occurring in a commercial 2024 aluminium alloy during isothermal ageing treatments at 170 deg. C for up to 120 h have been characterized using atom probe tomography. An early (0.5 h at 170 deg. C) rapid increase in hardness was correlated with the formation of fine scale (average 24 atom) solute clusters, comprising principally Mg and Cu, but with minor concentrations of Si and Zn. There was, in addition, evidence of significant segregation of Mg, Cu and Si to at least some fraction of grain boundaries and existing matrix dislocations. At peak hardness (80 h at 170 deg. C) the microstructure comprised coarse precipitates of S phase, with a composition approaching stoichiometric Al{sub 2}CuMg, a dense distribution of Guinier-Preston-Bagaryatsky zones elongated parallel to <1 0 0> in a matrix of {alpha}-Al and a residual distribution of smaller equiaxed solute clusters. Both the clusters and zones contained predominantly Mg and Cu, with minor concentrations of Si and Zn. The S phase contained small but significant (0.5-1.8 at.%) concentrations of Si, which was non-uniformly distributed in elongated domains within the laths of the S phase. In overaged samples (114 h at 170 deg. C) the microstructure comprised almost exclusively coarse S phase, Al{sub 2}Mg(Cu,Si), in assemblies suggestive of a combination of precipitate coarsening and coalescence.

Sha, G., E-mail: gang.sha@sydney.edu.au [Australian Research Council Centre of Excellence for Design in Light Metals (Australia); Australian Centre for Microscopy and Microanalysis, University of Sydney, New South Wales 2006 (Australia); Marceau, R.K.W. [Australian Research Council Centre of Excellence for Design in Light Metals (Australia); Australian Centre for Microscopy and Microanalysis, University of Sydney, New South Wales 2006 (Australia); Gao, X.; Muddle, B.C. [Australian Research Council Centre of Excellence for Design in Light Metals (Australia); Department of Materials Engineering, Monash University, Clayton, Victoria 3800 (Australia); Ringer, S.P. [Australian Research Council Centre of Excellence for Design in Light Metals (Australia); Australian Centre for Microscopy and Microanalysis, University of Sydney, New South Wales 2006 (Australia)

2011-02-15

172

Severe wear of a near eutectic aluminium-silicon alloy  

International Nuclear Information System (INIS)

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

173

Radiation effects in the aluminium alloys irradiated with neutrons  

International Nuclear Information System (INIS)

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

174

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-09-01

175

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 passivi...

Mohedano, Marta; Arrabal, Rau?l; Pardo, Angel; Paucar, Kari?n; Merino, M. Concepcio?n; Matykina, Endzhe; Mingo, Beatriz; Garce?s, Gerardo

2014-01-01

176

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

177

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

International Nuclear Information System (INIS)

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

178

Interaction of lead-borate glass with aluminium and iron-nickel alloys  

International Nuclear Information System (INIS)

Interaction of aluminium (AMG-6) and iron-nickel (47ND) alloys with lead-borate glass of PbO-73, BeO3-12, ZnO-10, Al2O3-3, SiO2-2 (mas. %) composition is investigated. It is determined that components of both soldered alloys interact actively with lead-borate glass melt that allows to obtain strong cohesion of glass with AMG-6 and 47ND metal alloys

179

Microstructure and mechanical properties of C355.0 cast aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Sieniawski, J.; Mro?wka-nowotnik, G.

2011-01-01

180

Clustering and formation of nano-precipitates in dilute aluminium and magnesium alloys  

International Nuclear Information System (INIS)

A nuclear magnetic resonance (NMR) method is described for monitoring the evolution of nano-scale precipitate structures in dilute aluminium and magnesium-based alloys. Three examples are given of recent work in this field: (i) 63Cu detection of Guinier-Preston zones (GPZs) and ?-phases in Al(Cu), (ii) 27Al detection of ?-phase (Mg17Al12) formation in Mg(Al) alloys and (iii) 45Sc detection of Al3Sc formation in Al(Sc) alloys

 
 
 
 
181

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Anju Ramesh; Saleem, N.; Najarajan, N. M.

2014-01-01

182

Electrochemical Study of Aluminium Alloy AA 5083 Corrosion Induced by Elemental Mercury in LNG Industries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrochemical corrosion studies of industrial Aluminium alloy AA 5083 corrosion in natural gas containing mercury metal and water as impurities showed to be a complex process. Single scan voltamograms of amalgamated electrode presents peaks of electrochemical oxidation around E = -1.4 volt/SCE and a corrosion potential Ecor = -1.6 volt/SCE showing an active amalgamated surface. Oxydation peak, Ip relating rate of electrochemical oxidation of aluminium was depending on three facto...

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

2006-01-01

183

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

184

Modelling research of hydrogen desorption from liquid aluminium and its alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Saternus, M.

2011-01-01

185

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Flores Ramirez, J. R.

2006-01-01

186

Electron microscopy study of hardened layers structure at electrospark alloying the VT-18 titanium alloy with aluminium  

International Nuclear Information System (INIS)

Presented are the results of metallographic, electron-microscopic, and X-ray structure analysis, of microhardness measurements and of the study of the electrode weight changes at electrospark alloying the VT-18 titanium alloy with aluminium. It is shown, that pulsating thermal and mechanical loadings in the process of electrospark alloying result in the electrode surface electroerosion, a discrete relief is being formed, which changes constantly in the process depending on the alloying time. Though with the process time the cathode weight gain increases, microareas of fracture in the hardened layer appear already at the initial stages of electrospark alloying

187

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

188

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zhu, G.

2012-01-01

189

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

Energy Technology Data Exchange (ETDEWEB)

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.

Hajewska, E. [Institute of Atomic Energy, Otwock-Swierk (Poland)

1993-11-01

190

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

International Nuclear Information System (INIS)

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

191

Adherence of electrodeposited Zn-Ni coatings on EN AW2024 T3 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of hexavalent chromium in surface treatments will be reduced in the future, as it is suspected to be carcinogenic. Electrodeposition of Zn-Ni, which is currently used on steel, represents a non-chromate alternative surface treatment for the corrosion protection of aluminium alloys. Zn-Ni coatings were electrodeposited onto an EN AW2024 T3 aluminium alloy sheet in a laboratory flow cell. To obtain several percentages of Ni in the coatings, solutions with different Ni2+ concentrations w...

Alexis, Joe?l; Adrian, Denise; Masri, Talal; Petit, Jacques-alain

2004-01-01

192

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The acid failure of aluminium alloy in 2 M hydrochloric acid solution in the presence of Vernonia amygdalina extract was investigated using gasometric technique. Aluminium alloy coupons of dimension 4 cm by 1 cm were immersed in test solutions of free acid and also those containing extract volumes of 2, 3, 4 and 5 cm3 at ambient temperature for 30 minutes. The volumes of hydrogen gas evolved as a result of the rate of reaction were recorded and analyzed. Analysis revealed that maximum inhibit...

Omotosho, Olugbenga A.; Ajayi, Oluseyi O.

2012-01-01

193

An indirect method for determining phosphorus in aluminium alloys by atomic-absorption spectrometry.  

Science.gov (United States)

An indirect method is described for the determination of phosphorus in aluminium alloys. Ammonium molybdate is added to a solution of the aluminium alloy and the molybdophosphoric acid formed is selectively extracted into n-butyl acetate. The twelve molybdenum atoms associated with each phosphate ion are determined by direct atomic-absorption spectrometry with the n-butyl acetate phase in a nitrous oxide-acetylene flame, with measurement at 313.2 nm. The most suitable conditions have been established and the effect of other ions has been studied. PMID:18963055

Bernal, J L; Del Nozal, M A; Deban, L; Aller, A J

1981-07-01

194

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

195

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

196

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

Directory of Open Access Journals (Sweden)

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

G. Venkateswarlu

2010-07-01

197

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

International Nuclear Information System (INIS)

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

198

Electrochemical Study of Aluminium Alloy AA 5083 Corrosion Induced by Elemental Mercury in LNG Industries  

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

D. Zerouali

2006-01-01

199

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

CERN Document Server

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

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

2002-01-01

200

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

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

Abdel-Nasser .M. Omran

2014-07-01

 
 
 
 
201

Evaluation Of Four Welding Arc Processes Applied To 6061 Aluminium Alloy  

International Nuclear Information System (INIS)

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.

202

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.

Cecchetto, L; Ambat, Rajan

2007-01-01

203

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

International Nuclear Information System (INIS)

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

204

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

205

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

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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 ...

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

2013-01-01

206

Development of tools for integrated optimisation and use of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zander, Johan

2011-01-01

207

Use of acoustic energy in the processing of molten aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

208

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

209

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 investigatio...

Laukli, Hans Ivar

2004-01-01

210

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.

211

Investigation of precipitation hardening in aluminium alloy by vickers microhardness and electrical resistance  

International Nuclear Information System (INIS)

Microhardness and electrical resistivity measurements were performed on aluminium 6061 alloy. The value of the logarithmic index of microhardness was 2.04. There is striking similarity between microhardness plot and that of electrical resistivity which is explained by distribution precipitates. (author)

212

The effect of nickel on alloy microstructure and electrochemical behaviour of AA1050 aluminium alloy in acid and alkaline solutions  

International Nuclear Information System (INIS)

The study investigates the influence of nickel and magnesium additions to AA1050 aluminium alloy on the alloy electrochemical behaviour in sodium hydroxide and hydrochloric solutions under conditions relevant to industries that use alkaline etching as a standard surface treatment procedure and to the lithographic and electronic industries where surface convolution is assisted by pitting in hydrochloric acid. Scanning and transmission electron microscopes were used to characterize the intermetallic particles, and scanning Kelvin probe microscopy was utilised in monitoring the surface potential. Nickel is shown to be incorporated into second phase particles, which mostly consisted of Al3Fe and ?-(AlFeSi) phases, resulting in enhanced cathodic activity on the aluminium surface. Consequently, the dissolution rates of the superpure aluminium, alloys without nickel addition and alloy with nickel addition are increased respectively in sodium hydroxide, and increased pitting is respectively promoted in hydrochloric acid. In contrast, the addition of magnesium to the alloy had negligible influence on the etching and pitting behaviour.

213

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

214

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

215

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

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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

216

Investigation into phase formation during diffusion interaction of tungsten-rhenium alloy with liquid aluminium under conditions of weightlessness  

International Nuclear Information System (INIS)

The laws governing diffusion interaction between aluminium melt and solid tungsten-rhenium alloy under conditions of the joint space flight of Soyuz and Apollo spaceships have been studied. It is shown that a diphase layer was formed between the alloy and aluminium during high temperature annealing (Tsub(max) approximately 1030 deg C), and individual phase fragments are found in various aluminium matrix regions in metallographic specimen sections examined. The main laws governing the phase formation conditions observed under ground conditions are also maintained during the space flight. The analysis of the results obtained made it possible to conclude that zero-g produces only an insignificant effect on diffusion phase forming process conditions. Among the specific features of the above interaction under weightlessness conditions were: increased porosity in the diffusion layer-tungsten rhenium alloy contact zone; precipitation of high aluminium phases in aluminium matrix

217

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.

218

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

219

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

220

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

 
 
 
 
221

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

222

Low cycle fatigue testing of 304LN stainless and 5083-0 aluminium alloys  

International Nuclear Information System (INIS)

Fatigue data were obtained at 40K for stainless alloy AISI 304LN (3.8 cm plate) and aluminium alloy 5083-0 (2.5 cm plate). The specimen geometry, testing apparatus, and technique used to obtain the fatigue data are described. Testing at 770 and 40K was performed in a cryostat system prepared for low-cycle fatigue testing. Experimental test results for the two alloys are discussed and compared with other available information to obtain a comparison with alternate candidate materials

223

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

Directory of Open Access Journals (Sweden)

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

Nikolay A. Suy

2013-03-01

224

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

225

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

226

Study od early stages of structure formation in irradiated aluminium alloys  

International Nuclear Information System (INIS)

Solid solution decomposition in ageing D16, D20 and V95 aluminium alloys under gamma- and 14 MeV electrons irradiation is investigated. Change of the form, structure and dimensions of Guinier-Preston zones formed at the initial decomposition stage is disclosed. The role of crystal lattice defects and alloying element atoms in the process of solid solution decomposition is considered. It is noted that intermetallics dissolution takes place under large dose irradiation, the alloy structure after ageing is completely changed in this case. Radiation temperature produces an essential effect

227

Summary of structural refinement in hi-silicon aluminium piston alloy with phosphorous as grain refiner  

International Nuclear Information System (INIS)

Aluminium Silicon Alloys are extensively used in a wide variety of applications. There are numerous variables in composition, production control, final structure which can influence the mechanical properties of Hi - Silicon Piston alloys. Hypereutectic AlSi alloys develop coarse grain primary silicon crystals, which have a strong negative effect on the tensile strength, the ductility, and the hardness. These crystals slow machining and reduce the tool life considerably. Phosphorous addition produce a fine, evenly spread crystal structure, lamellar structure of the silicon changes into a granular structure. (author)

228

THE MICROSTRUCTURAL EVOLUTION DURING DEFORMATION UNDER SEVERAL STRAIN RATES IN A COMMERCIAL 5182 ALUMINIUM ALLOY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The flow stress of a commercial 5182 aluminum alloy has been investigated as a function of strain rates in the range from 1x10-3 to 4x103s-1 at room temperature. The 5182 alloy exhibited the negative strain rate sensitivity of flow stress in a strain rate range below 102 s-1, of which the maximum flow stress decreased with increasing strain rate. This tend in flow stress with strain rates was observed for other commercial aluminium alloys which include magnesium atoms in solute such as the 30...

Higashi, K.; Mukai, T.; Kaizu, K.; Tsuchida, S.; Tanimura, S.

1991-01-01

229

Study of mechanical properties in neutron irradiated aluminium base alloys  

International Nuclear Information System (INIS)

Commericial AMG-2 alloy and ternary Al-Mg-Sc alloy (Al-2.5% Mg-0.4% Sc) have been irradiated at 100+-25 deg C in the reactor. Neutron dose (> 0.1 MeV) constituted 1.3x1020 neutronxcm-2. Mechanical properties of the alloys in the temperature range from 20 to 300 deg C have been determined after irradiation. It is established that irradiation does not influence the ultimate strengths and yield limits of the alloys in the whole investigated range of temperatures. In the AMG-2 irradiated alloy observed is both the decrease of absolute values os specific elongation and the change of the temperature dependence character. Irradiation has not influenced the plasticity of Al-Mg-Sc alloys for all test temperatures. Scandium effect on radiation resistance of Al-Mg- alloys is studied

230

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

231

Laser beam welding of high strength aluminium-lithium alloys; Laserstrahlschweissen von hochfesten Aluminium-Lithium Legierungen  

Energy Technology Data Exchange (ETDEWEB)

The present development in aircraft industry determined by the demand for a higher cost-effectiveness. Laser beam welding is one of the most promising joining technologies for the application in the aircraft industry through the considerable reduction of the production costs. Furthermore the weight of an aircraft structure can be reduced by the use of light and high strength aluminium alloys. This paper deals with the development of a process for the laser beam welding of a skin-stringer-joint where the Al-Li-alloy AA2196 is used as stringer material and the Al-Li-alloy AA2198 is used as skin and stringer material. By the use of design of experiments the optimal welding process parameters for different material combinations were determined which will be used for the welding of a 5-stringer panel. Therefore the weld seams of the joints were tested for irregularities and microstructural characteristics. In addition several mechanical tests were performed, which define the quality of the welded joint. Furthermore the influence of the oxide layer and the welding preparation on the welding performance was investigated. (orig.) [German] Die derzeitigen Entwicklungen im Flugzeugbau werden durch die allgemeine Forderung nach einer Steigerung der Wirtschaftlichkeit bestimmt. Das Laserstrahlschweissen ist dabei eines der vielversprechendsten Fuegeverfahren fuer die Anwendung im Flugzeugbau durch das die Herstellungskosten deutlich reduziert werden koennen. Zudem kann durch die Verwendung von leichten und hochfesten Aluminium-Legierungen das Gewicht einer Flugzeugstruktur zusaetzlich reduziert werden. Die vorliegende Arbeit befasst sich mit der Entwicklung eines Prozesses zum Laserstrahlschweissen einer Skin-Stringer-Verbindung aus den Aluminium-Lithium-Legierungen AA2196 (als Stringer-Werkstoff) und AA2198 (als Skin- und Stringer-Werkstoff). Unter Verwendung der statistischen Versuchsplanung wurden die optimalen Einstellungen der Schweissprozessparameter fuer die verschiedenen Werkstoffkombinationen ermittelt, die Anwendung beim Schweissen eines 5-Stringer-Paneels finden sollen. Hierzu wurden die Schweissnaehte eingehend auf Unregelmaessigkeiten und Gefuegebesonderheiten untersucht sowie verschiedenen mechanischen Pruefungen unterzogen, die die Qualitaet der Schweissverbindung bestimmen. Weiterhin wurde auch der Einfluss der Oxidschicht und der Nahtvorbereitung auf das Schweissergebnis untersucht.

Enz, Josephin

2012-07-01

232

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

233

Research on Cutting the Plasma of Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper analyses the plasma cutting process of nonferrous metals. The influence of aluminium and modes of brass plates cut on the quality of the cut using air plasma are presented. The modes of plasma cutting counting differences in speed, flow, the tip of the angle and the distance between the shell and the cutting plate are analysed. According to the given results, dependences are p...

Mindaugas Jašinskas; Irmantas Gedzevi?ius; Giedrius Garbin?ius; Justinas Gargasas

2011-01-01

234

Wear Properties of Alumina Particles Reinforced Aluminium Alloy Matrix Composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

235

Superlattices in iron-rich iron-aluminium alloys  

International Nuclear Information System (INIS)

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

236

Laser surface treatment of magnesium alloys with aluminium oxide powder  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

237

Influence of temperature and strain rate on the formability of aluminium alloys: Comparison between experimental and predictive results  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of sheet metal forming processes can be limited by the formability of materials, especially in the case of aluminium alloys. To improve the formability, warm forming processes can be considered. In this work, the effects of temperature and strain rate on the formability of a given aluminium alloy (AA5086) have been studied by means of both experimental and predictive approaches. Experimental tests have been carried out with a Marciniak stamping experimental device. Forming limit curve...

Chu, Xingrong; Leotoing, Lionel; Guines, Dominique; Ragneau, Eric

2014-01-01

238

Experimental characterization and prediction of the formability of an aluminium alloy considering temperature and strain rate effects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sheet metal forming processes are widely used in industry. Nevertheless, the use of these processes is limited by the formability of the considered material, in particular in the case of the aluminium alloys. To improve the formability, warm forming processes can be considered. The objective of this work is to study by means of both experimental and numerical approaches, the effects of temperature and strain rate on the formability of AA5086 aluminium alloy sheets and to propose a modeling su...

Chu, Xingrong

2013-01-01

239

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Larignon, Ce?line; Alexis, Joe?l; Andrieu, Eric; Lacroix, Loi?c; Odemer, Gre?gory; Blanc, Christine

2013-01-01

240

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Cepeda-jime?nez, C. M.; Garci?a-infanta, J. M.; Pozuelo, M.; Ruano, Oscar Antonio; Carren?o, Fernando

2009-01-01

 
 
 
 
241

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2007-01-01

242

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

243

Aluminium, molybdenum and zirconium distribution between phases in Ti - Al - Mo - Zr alloys  

International Nuclear Information System (INIS)

The distribution of zirconium neutral element combined with highly effective stabilizers - aluminium (?-stabilizer) and molybdenum (?-stabilizer) between ?- and ?-phases, is studied as well as their mutual effect on solubility in the said phases of titanium alloys from different phase regions of polythermal cross sections of Ti-2Mo-3Zr-Al (cross section 1) and Ti-0.5Mo-3Zr-Al (cross section 2) of the Ti-Al-Zr system. It is shown that in the studied alloys Ti-2Mo-3Zr-Al and Ti-0.5Mo-3Zr-Al alumium and molybdenum between (?2)-and ?(?') phases are distributed irregularly. The coefficient of molybdenum distribution irregularity (Csub(Mo)) constitutes 2-13, aluminium (Ksub(Al)) - 1.2-1.4. Zirconium behaves in alloys similar to ?-stabilizers, i. e. zirconium concentration in ?(?')-phase is higher, than in ?(?2)-phase. Csub(Zr) between ?(?2)- and ?(?') phases in some cases attains 4. Zirconium effect as ?-stabilizer grows with increase of molybdenum conccetration in alloys and decreases with aluminium concentration growth

244

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

245

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)

246

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.

247

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

248

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

249

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

International Nuclear Information System (INIS)

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

250

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

251

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

252

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

253

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

254

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

International Nuclear Information System (INIS)

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

255

Reactivity of thermally oxidized and unoxidized SiC particulates with aluminium-silicon alloys  

Energy Technology Data Exchange (ETDEWEB)

The reactivity of unoxidized and thermally oxidized SiC particulates with Al-Si alloys was investigated. The composites were fabricated by means of pressure infiltration, and had a particle volume fraction of around 0.58. The silicon content was varied in the range 0-8 wt.%. The particulates were characterized by means of thermal programmed desorption, thermal programmed reactions, scanning electron microscopy and IR absorption, and their oxidation was followed by means of weight gain techniques, adsorption isotherms and X-ray diffraction. The extent of the reaction was determined by means of optical microscopy and differential thermal analysis. The results for unoxidized SiC agree with those of previous studies in the sense that increasing the silicon content of the alloy retards the reaction between aluminium and SiC. However, those for oxidized SiC indicate that once aluminium has reacted with the oxide to produce aluminia, the direct reaction between aluminium and silicon carbide proceeds at a pace similar to that found for unoxidized SiC. However, optical microscopy shows that the morphologies and spatial distributions of the aluminium carbide produced in the reaction are different in the two cases.

Narciso, J.; Garcia-Cordovilla, C. (Industria Espanola del Aluminio, Centro de Investigacion y Desarrollo, Alicante (Spain)); Louis, E. (Industria Espanola del Aluminio, Centro de Investigacion y Desarrollo, Alicante (Spain) Dept. de Fisica Aplicada, Univ. de Alicante (Spain))

1992-11-01

256

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

International Nuclear Information System (INIS)

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

257

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

International Nuclear Information System (INIS)

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

258

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Jaradeh, Majed

2006-01-01

259

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

International Nuclear Information System (INIS)

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.

260

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

 
 
 
 
261

Mechanical properties and corrosion behaviour of MIG welded 5083 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

For this study 5083 Aluminium alloy plates, as used in automobiles and watercraft, were experimentally MIG welded. The plates were joined with different wires and at various currents. The effects of welding with different parameters on the mechanical and corrosion properties were investigated. The corrosion behaviour of the MIG welded 5083 Aluminium base material was also investigated. The effects of the chemical composition of the filler material on the mechanical properties were examined by metallographic inspection and tensile testing. By EDS and XRD analyses of specimens it turned out that different structures in the weld metal (Cu3Si) affect its mechanical properties. The mechanical properties of the specimens welded with 5356 filler metal were found as quite well improved as compared to those specimens welded with 4043 and 5183 filler material. The results of the metallographic analysis, and mechanical and corrosion tests exhibited that the 5356 filler material was most suitable for the 5083 Al alloy base material. (orig.)

Durmus, Huelya [Celal Bayar Univ., Turgutlu-Manisa (Turkey)

2011-07-01

262

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

263

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.

264

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

265

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

266

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

Energy Technology Data Exchange (ETDEWEB)

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., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Georgiou, E.P.; Tsopani, A.; Piperi, L. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

2011-03-15

267

Electrochemical characteristics of aluminium and its alloys in water at temperature up to 90 deg  

International Nuclear Information System (INIS)

Proposed is the methods of plotting anode potentiodynamical curves of aluminium (99.99%) and alloys of the Al-Mg-Si system (0.4-0.9% Mg and 0.7-1.2% Si) in distilled water and weakly-mineralized electrolytes at temperatures of 20-90 deg, revealing corrosion behaviour of these metals. The methods permits to obtain a complete polarized curve with three characteristical regions of potentials (region of active dissolution, active-passive state and passive state) at simultaneous compensation of omic voltage drop. Experiments carried out have shown that the rate of aluminium solution in active region of potentials increases with temperature increase especially at 90 deg but the passivation potential. Corrosion potential does not practically change with temperature. In distilled water it constitutes 0.80 B for Al, in weakly mineralized - 1.10 B. Al-Mg-Si; alloy is more corrosion-resistant in the studied media in comparison with pure Al

268

In situ fabrication of Al3Ti particle reinforced aluminium alloy metal-matrix composites  

International Nuclear Information System (INIS)

Titanium tri-aluminide (Al3Ti) particles were dispersed homogeneously into a castable aluminium alloy matrix by the aluminothermic reduction of hexafluorotitanate (K2TiF6) under different conditions. Al3Ti particles in different morphologies and sizes were produced by changing the fabrication conditions, such as composition of the flux, the temperature and holding time. The coarsening and growth of the Al3Ti particulates are principally affected by other elements present in the flux during fabrication. The effects of the temperature and holding time, alloying elements and the composition of flux on the dispersion of the reinforcement were examined by using SEM and X-ray diffraction techniques. The observed results are explained in terms of the different growth behaviour of the Al3Ti particles under different conditions. The dispersion of the Al3Ti particles and the Al/Al3Ti interfacial bonding are explained by the solidification of aluminium

269

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

270

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

271

Research on Cutting the Plasma of Aluminium Alloys  

Directory of Open Access Journals (Sweden)

Full Text Available The paper analyses the plasma cutting process of nonferrous metals. The influence of aluminium and modes of brass plates cut on the quality of the cut using air plasma are presented. The modes of plasma cutting counting differences in speed, flow, the tip of the angle and the distance between the shell and the cutting plate are analysed. According to the given results, dependences are proposed. A particular influence of the cut parameter on the quality of the cut is determined.Article in Lithuanian

Mindaugas Jašinskas

2011-02-01

272

New process produces superplastic aerospace/automotive aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-12-01

273

Thermal Analysis on Butt Welded Aluminium Alloy AA7075 Plate Using FEM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Pal Pandi, M.; Kannan, Dr R.

2014-01-01

274

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2002-01-01

275

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

276

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

277

A study of cavity nucleation during superplastic deformation of high strength aluminium alloy 7475  

Energy Technology Data Exchange (ETDEWEB)

Cavity nucleation during superplastic deformation of a high strength aluminium alloy has been studied using a high voltage electron microscope and an optical microscope. The results show that cavity nucleation is only owing to superplastic deformation and not to pre-existing microvoids which may be introduced during thermomechanical processing. The main reason for cavity nucleation is the high stress concentration at discontinuities in the plane of the grain boundary due to grain boundary sliding.

Jiang Xinggang (Dept. of Materials Physics, Univ. of Science and Technology, Beijing (China)); Cui Jianzhong; Ma Longxiang (Northeast Univ. of Technology, Dept. of Metal Forming, Shenyang (China))

1992-09-01

278

STATISTICAL STUDY OF THE PITTING CORROSION OF THE 8090 ALUMINIUM LITHIUM ALLOY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pitting corrosion of the 8090 Aluminium Lithium alloy has been studied in 0.01 M and 0.1 M Na2SO4 solutions having various chloride contents. In this media, pits are induced at random potentials ; therefore a statistical study of pit induction times in potentiostatic conditions and pitting potentials in potentiodynamic conditions has been performed. The induction times obey a log normal law. In solutions with high chloride contents, the distributions of pitting potentials are well describ...

Schnuriger, S.; Mankowski, G.; Roques, Y.; Chatainier, G.; Dabosi, F.

1987-01-01

279

The effect of shot peening on fatigue and fretting-fatigue of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Plain-fatigue and fretting-fatigue tests have been carried out on the two peak-aged, high-strength aluminium alloys, 7010 and 8090, in the unpeened and shot peened conditions. Shot peening produced a highly deformed surface containing many deep dimples and folds from which fatigue cracks rapidly initiated. Although initiation was early, propagation through the peened surface layers was retarded by the residual compressive stresses introduced by the peening treatment; this retardation bein...

Fair, G. H.

1988-01-01

280

Hot-crack test for aluminium alloys welds using TIG process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hot cracking is a critical defect frequently observed during welding of aluminium alloys. In order to better understand the interaction between cracking phenomenon, process parameters, mechanical factors and microstructures resulting from solidi?cation after welding, an original hot-cracking test during welding is developed. According to in-situ observations and post mortem analyses, hot cracking mechanisms are investigated, taking into account the interaction between microstructural ...

Deschaux-beaume F.; Bordreuil C.; Niel A.; Fras G.

2010-01-01

 
 
 
 
281

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

282

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 (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

2014-12-01

283

Cold weldability of aluminium alloys : influence of the mechanical load on the formation of metallic bonds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In solid-state welding, if the temperature generally has an important role (diffusion, recrystallization, etc.), a mechanical load is also necessary to override the oxide layer which naturally covers aluminium alloys. This work aims to understand the influence of the mechanical load on the formation of metallic bonds. To this end two cold weldability tests have been introduced. Firstly the plane strain channel-die compression of two cuboids sample aims to increase the surface at the welding i...

Siret, Olivier

2010-01-01

284

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

285

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Zirconia coating was produced on aluminium alloy by plasma electrolytic oxidation (PEO). The alkaline electrolyte containing Zr(OH)ª4 powders was used. The composition and structure of the coating were investigated by XRD, EPMA. The results show that the coating consists of ª«t-ZrO2, ª«m-ZrO2, ª«¦?/SUB>-Al2O3 and ª«¦|/EM>-Al2O3. ª«t-ZrOª2 is the main ph...

Xin Shi-gang, Zhao Rong-gen

2009-01-01

286

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

287

The influence of aluminium alloy quench sensitivity on the magnitude of heat treatment induced residual stress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2006-01-01

288

Numerical modelling of complex shaped particle break-up with application to rolling of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aluminium alloy AA5182, largely employed in the form of plates used for the body panels in automotive industry, contains intermetallic particles Mg2Si and AlxFe. In as cast state, these particles (of a size > 50 µm) present complex shapes. During hot rolling, the particles are broken and redistributed in the sheet metal. However, the size and the spatial distribution of the intermetallic particles mainly control the formability of sheets after cold transformation.This work id...

Moulin, Nicolas

2008-01-01

289

3D morphological analysis of complex shape particles : Application to intermetallic particles in aluminium alloy.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this PhD-thesis, the studied material is an aluminium alloys 5182 containing two particles types: Alx(Fe,Mn) and Mg2Si. During industrial rolling, particles are broken up, and redistributed in the volume of the sheet.As particles controls surface aspect and formability of the final sheet, the work presented is based on two issues: to highlight volume distribution of intermetallic particles, and to characterize their three-dimensional shapes during the rolling process. Thus, samples e...

Parra-denis, Estelle

2007-01-01

290

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

291

Microstructure and hot tearing of 6000 series aluminium alloys laser welds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

There has been a rapid growth in the use of the laser welding process due to its higher productivity rate compared to conventional processes. However its development in the field of aluminium alloys has been limited due to the presence of solidification defects (e.g. porosity, hot cracking). This study is focused on the understanding of the problem of hot cracking during welding. Numerous welding tests were done under different conditions, followed by microstructural examinations so as to und...

Fabregue, Damien

2004-01-01

292

Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

293

Behaviour modelling of aluminium alloy sheet for Single Point Incremental Forming  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work is to identify behaviour models of an aluminium alloy sheet formed by incremental stamping process by using both numerical simulations (FEM) and experimental procedures. The procedure developed will be used in Single Point Incremental Forming (SPIF) in using several original experimental tests allowing to reproduce loading paths close to those induced in the industrial operations and full-field measurements by 3D-Digital Image Correlation (DIC).

Decultot, Nicolas; Velay, Vincent; Robert, Laurent; Bernhart, Ge?rard; Massoni, Elisabeth

2008-01-01

294

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

295

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.)

296

A predictive fatigue life model for anodized 7050 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study is to predict fatigue life of anodized 7050 aluminum alloy specimens. In the case of anodized 7050-T7451 alloy, fractographic observations of fatigue tested specimens showed that pickling pits were the predominant sites for crack nucleation and subsequent failure. It has been shown that fatigue failure was favored by the presence of multiple cracks. From these experimental results, a fatigue life predictive model has been developed including multi-site crack consid...

Chaussumier, Michel; Mabru, Catherine; Shahzad, Majid; Chieragatti, Re?my; Rezai?-aria, Farhad

2013-01-01

297

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

298

Advances in aluminium alloy products for structural applications in transportation  

Energy Technology Data Exchange (ETDEWEB)

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

Staley, J.T. (Aluminum Co. of America, Alcoa Technical Center, PA (United States)); Lege, D.J. (Aluminum Co. of America, Alcoa Technical Center, PA (United States))

1993-11-01

299

Advances in aluminium alloy products for structural applications in transportation  

International Nuclear Information System (INIS)

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

300

Technological approaches by laser beam welding of aluminium alloys and influence of errors in manufacturing process  

Science.gov (United States)

The explosive development of modern manufacturing technologies, particularly the laser beam manufacturing, has raised new challenges in the field of research. The laser beam welding process may be influenced by errors appearing from different causes. In this paper the authors present the influence of errors during the experiments regarding the laser beam welding of aluminium alloy. In the physical experiment, two major geometric welding characteristics (the welding surface and the welding width) of an aluminium alloy AlMgSi 1 were measured at different welding speeds, using a solid state laser Nd:YAG, HL 4006D. With the aim of obtaining the best results, a CCD-Camera was assembled on the device allowing to capture the most accurate photos from the experiments. The appearance of errors is more likely to be found in the domain of high rate welding speeds than in those of low welding speeds. The data analysis based on the dispersion criterion is useful to characterize the influence of thermal parameters of aluminium alloy upon the laser beam welding surface and width, which may be extended to other new materials with the same characteristics. The present researches started together with the University of Stuttgart will be continued at the Technical University of Cluj-Napoca with a new laser equipment.

Popa, Marcel S.; Rus, Calin; Preja, Dan; Moldovan, Raul

2005-02-01

 
 
 
 
301

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

302

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

International Nuclear Information System (INIS)

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

303

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

304

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

305

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.

306

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

307

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

308

Real-time observation of grain nucleation and growth during solidification of aluminium alloys  

International Nuclear Information System (INIS)

The crystallisation kinetics of liquid aluminium-titanium alloys with microscopic TiB2 particles added to refine the grain size in the solidified material was studied by X-ray diffraction measurements at a synchrotron source. Real-time observation of the formation and growth of individual grains reveals the central role played by the added TiB2 particles during solidification. Prior to the main transformation, weak reflections of a metastable TiAl3 phase were detected. This observation finally pinpoints the highly debated mechanism responsible for enhanced grain nucleation in Al-Ti-B alloys

309

The determination of boron in aluminium and aluminium-magnesium alloy by charged particle activation analyses  

International Nuclear Information System (INIS)

An instrumental determination of boron in Al and Al-Mg alloy by proton activation using the reaction 10B(p,?)7Be is described. Pellets, pressed from boric acid are used as a standard. This method is compared with two destructive methods, based on the 10B(4He,n)13N and 10B(d,n)11C reactions. The agreement between the different methods is satisfactory. The boron concentration was 1.2 and 66 ?g/g-1 for Al and Al-Mg alloy respectively. The results for Al-Mg alloy were also compared with photometry and flame emission spectrometry. Under the activation of B.C.R. of the Commission of European Communities, the possibilities for the preparation and analysis of a certified reference material for boron in Al alloys are being investigated. As different undependent and absolute analytical techniques are required, methods based on 3 different nuclear reactions were developed. (orig./RB)

310

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

Scientific Electronic Library Online (English)

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

Oladele Isiaka, Oluwole; Omotoyinbo Joseph, Ajibade.

2010-06-01

311

Precipitation hardening of cast Zr-containing A356 aluminium alloy  

International Nuclear Information System (INIS)

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

312

Study on segregation of aluminium-uranium alloys  

International Nuclear Information System (INIS)

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

313

Corrosion of pure aluminium and aluminium alloy: a comparative study using a slow positron beam  

Energy Technology Data Exchange (ETDEWEB)

Corrosion-related defects in pure Al and AA 2037 Al alloy have been investigated by positron beam-based Doppler broadening energy spectroscopy. Defect profiles have been analyzed by measuring the S parameter as a function of incident positron energy up to 30 keV. When pure Al samples are immersed in 1M NaOH for various times, a significant increase in the S parameter near the surface is observed. This implies that the corrosion process involves the creation of defects and nanometer voids. In contrast, a significant decrease in the S parameter is observed after the corrosion of water-quenched Al alloy by the same method, which is interpreted as being a result of Cu enrichment near the metal-oxide interface layer.

Wu, Y C; Li, P H; Xue, X D; Wang, S J [Department of Physics, Wuhan University, Wuhan 430072 (China); Kallis, A; Coleman, P G [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom); Zhai, T, E-mail: ycwu@whu.edu.cn [Chemical and Materials Engineering Department, University of Kentucky, Lexington, KY 40506-0046 (United States)

2011-01-01

314

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.

315

Phase-oriented surface segregation in an aluminium casting alloy  

Science.gov (United States)

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.

Nguyen, Chuong L.; Atanacio, Armand; Zhang, Wei; Prince, Kathryn E.; Hyland, Margaret M.; Metson, James B.

2009-02-01

316

Phase-oriented surface segregation in an aluminium casting alloy  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-02-15

317

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.

318

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

319

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

2013-09-01

320

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

International Nuclear Information System (INIS)

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

 
 
 
 
321

Electrochemical investigation of aluminium alloys in hot 3 pc sodium chloride solutions. Application to the method of polarization resistance  

International Nuclear Information System (INIS)

This research thesis reports the elaboration and the investigation of four types of aluminium alloys (Al-Mg, Al-Cu, Al-Zn and Al-Ti with weight concentration ranging from 0,01 to 10 pc) in order to better understand corrosion phenomena related to industrial alloys. The influence of alloying elements on aluminium corrosion resistance in an aqueous solution of sodium chloride at 3 pc (marine environment), at pH 7 and 100 C has been studied. Pure aluminium and industrial alloys such as AG4MC, AG3, AG5, AU4G and 6061 have been examined under the same conditions. Corrosion assessment has been performed by using polarization resistance and electrochemical characteristics measured from current-voltage curves which also give the failure potential which characterizes the susceptibility to pitting corrosion. The validity of this method of polarization resistance is discussed

322

Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate  

International Nuclear Information System (INIS)

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

323

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

324

The high throughput assessment of aluminium alloy corrosion using fluorometric methods. Part I - Development of a fluorometric method to quantify aluminium ion concentration  

International Nuclear Information System (INIS)

This paper examines a new method developed for the rapid assessment of corrosion inhibitors and their combinations for aluminium alloy 2024-T3 (AA2024-T3). Two fluorometric probes, lumogallion and morin, were used to rapidly assess the concentration of aluminium ions in solution through the use of a spectrophotometric plate reader. Fourteen potential inhibitor compounds and other assay constituents were screened for fluoroprobe interference: sodium chromate, sodium metavanadate, cerium chloride, lanthanum chloride, europium chloride, gadolinium chloride, neodymium chloride, yttrium chloride, barium metaborate, sodium metatungstate, potassium phosphate, sodium metasilicate, sodium phosphate, and sodium molybdate. Calibration curves were established for the two probes

325

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

326

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

Directory of Open Access Journals (Sweden)

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

327

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

International Nuclear Information System (INIS)

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

328

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

329

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

Directory of Open Access Journals (Sweden)

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

Victor ANJO

2013-11-01

330

Creation of nanostructured composite modifiers for aluminium alloys  

International Nuclear Information System (INIS)

Presented fundamentally new physical and chemical aspects of the creation of nanostructured composite ceramic fillers of various systems based on micro-and ultrafine powders of oxides and nitrides. The initial charge serves as donor formers of nanoscale fillers due to chemical reactions which take place in it, as well as media extenders in the melt and a uniform distribution in them. It was established that the developed dispersing fillers have a significant impact on the structure of the alloy, leading to a decrease in grain size in 5-30 times. The friction coefficient of developed cast composites in boundary friction is reduced by 3-8 times, wear resistance increases to 55 times the carrying capacity increases 2 times compared with the original alloy. (authors)

331

Creep properties of 7075 aluminium alloy under intermittent stressing  

International Nuclear Information System (INIS)

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

332

The fatigue response of the aluminium-lithium alloy, 8090  

Science.gov (United States)

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

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

1989-01-01

333

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

334

Tensile behavior of dissimilar friction stir welded joints of aluminium alloys  

International Nuclear Information System (INIS)

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

335

The solidification behavior of dilute aluminium-scandium alloys  

International Nuclear Information System (INIS)

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

336

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)

337

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

International Nuclear Information System (INIS)

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

338

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

International Nuclear Information System (INIS)

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

339

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

Science.gov (United States)

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

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

2005-12-01

340

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

International Nuclear Information System (INIS)

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

 
 
 
 
341

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-15

342

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

International Nuclear Information System (INIS)

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

343

Precipitation and plasticity couplings in a 7xxx aluminium alloy: application to thermomechanical treatments for distortion correction of aerospace component  

Digital Repository Infrastructure Vision for European Research (DRIVER)

7xxx aluminium alloys are high strength alloys mainly used for aerospace applications due to their high specific mechanical properties. Manufacturing these age-hardenable alloys involves complex thermomechanical treatments that develop the precipitation microstructure responsible for the mechanical properties. Undesirable long-range internal stresses are also produced during these treatments, and may induce severe distortions in the final products. Different thermomechanical processes: shot p...

Fribourg, Guillaume

2009-01-01

344

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2006-01-01

345

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

346

High speed twin roll casting of 6016 aluminium alloy strip  

Directory of Open Access Journals (Sweden)

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

H. Sakaguchi

2007-01-01

347

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

348

The microstructure and precipitation kinetics of a cast aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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{sup -1}, which is approximately the activation energy for diffusion of Cu and/or Si in Al, indicating diffusion-controlled precipitate growth.

Ovono, D. Ovono [Laboratoire Roberval, University of Technology of Compiegne, 60205 Compiegne (France)]. E-mail: delavand.ovono-ovono@utc.fr; Guillot, I. [Centre d' Etudes de Chimie Metallurgie, UPR2801 CNRS, 94407 Vitry-sur-Seine (France); Massinon, D. [Fonderie Montupet, 60181 Nogent-sur-Oise (France)

2006-08-15

349

Forming a lever preform made of aluminium alloy 2014  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents the results of theoretical and experimental analyses of forge rolling for producing a lever preform made of aluminum alloy 2014. The forge rolling process was performed in an oval-circle rolling system. To verify the technological assumptions made, a comprehensive numerical analysis by finite element method was first performed, followed by experimental tests. The investigation demonstrated a high agreement between the numerical results and those obtained experimentally under real conditions. The numerical simulations allowed the determination of the distributions of strains, temperatures and normalized Cockcroft-Latham ductile fracture criterion.

T. Bulzak

2014-10-01

350

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

351

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

Energy Technology Data Exchange (ETDEWEB)

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

Blandin, J.J.; Varloteaux, A.; Suery, M. [Inst. National Polytechnique de Grenoble, Saint Martin d`Heres (France); Hong, B.; L`Esperance, G. [Ecole Polytechnique de Montreal, Quebec (Canada). Centre de Caracterisation Microscopique des Materiaux

1996-06-01

352

Eutectic grain size and strontium concentration in hypoeutectic aluminium-silicon alloys  

International Nuclear Information System (INIS)

Recently it has been shown that modification with strontium causes an increase in the size of eutectic grains. The eutectic grain size increases because there are fewer nucleation events, possibly due to the poisoning of phosphorus-based nuclei that are active in the unmodified alloy. The current paper investigates the effect of strontium concentration on the eutectic grain size. In the aluminium-10 wt.% silicon alloy used in this research, for fixed casting conditions, the eutectic grain size increases as the strontium concentration increases up to approximately 150 ppm, beyond which the grain size is relatively stable. This critical strontium concentration is likely to differ depending on the composition of the base alloy, including the concentration of minor elements and impurities. It is concluded that processing and in-service properties of strontium modified aluminium-silicon castings are likely to be more stable if a minimum critical strontium concentration is exceeded. If operating below this critical strontium concentration exceptional control over composition and casting conditions is required

353

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

354

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

355

Determination of Homogenisation Parameter for Extrusion of Locally Produced Aluminium Alloys 6060  

International Nuclear Information System (INIS)

Aluminium billet 6060 as a raw materials of extrusion industry has been produced and used locally in Indonesia. In order to determinate the homogenization parameter suitable for this local billet, microstructure characterization of this alloys is required. Microstructure characterization of the alloy have been done using metallography technique including measurement of the Mg2Si solvus and solidus temperatures using differential thermal analyzer (DTA). The results show that the Mg2Si and AlFeSi phases dominate the microstructure of the as-cast alloys. The Mg2Si solvus and solidus of the alloy are found around 540 oC and 605 oC, respectively. The conductivity measurement indicates that increasing the soaking time to 3 hours reduces the conductivity, meaning the number of alloying elements going into solid solution increases. The parameter of homogenization for extrusion of this alloy was decided to be = 595 oC/3 hour air cooling at which the transformation of ? -AlFSi to ?-ALFeSi ha taken place. (author)

356

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

357

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

International Nuclear Information System (INIS)

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

358

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

359

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

Directory of Open Access Journals (Sweden)

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

360

Simulated nucleation textures of recrystallization during multiple pass hot rolling of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

A combination of several physically based models is used to simulate the development of crystallographic texture during deformation and recrystallisation in multiple pass hot rolling of a commercial aluminium alloy. Streamlines containing deformation data (e.g. strain rates, displacement gradients) were used to calculate the evolution of material properties during deformation with a dislocation density based flow stress model and a Taylor type deformation texture model which accounts for grain interaction. The texture development during the interpass time was modelled by an analytical recrystallisation model. (orig.)

Goerdeler, M.; Crumbach, M.; Gottstein, G. [Inst. fuer Metallkunde und Metallphysik, RWTH Aachen, Aachen (Germany)

2002-07-01

 
 
 
 
361

Integral modelling of texture evolution in multiple pass hot rolling of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The interaction of several physically based models for the development of crystallographic texture and microstructure during deformation and recrystallisation is exemplified in two cases of multiple pass hot rolling of commercial aluminium alloys. In this study streamlines output by the FE-code LARSTRAN/SHAPE and a model based on elementary rolling theory have been used respectively to calculate the evolution of material properties during deformation with a dislocation density based flow stress model and a Taylor type deformation texture model which considers grain interaction. To model the texture development during the interpass times between the rolling passes, an analytical recrystallisation model has been applied (orig.)

Goerdeler, M.; Crumbach, M.; Gottstein, G. [Inst. fuer Metallkunde und Metallphysik, RWTH Aachen, Aachen (Germany); Neumann, L.; Luce, R.; Kopp, R. [Inst. fuer Bildsame Formgebung, RWTH Aachen, Aachen (Germany); Allen, C.M.; Winden, M.v.d. [Corus Research, Development and Technology, IJmuiden Technology Centre, IJmuiden (Netherlands); Karhausen, K.F. [VAW aluminium AG, Research and Development, Bonn (Germany)

2002-07-01

362

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

363

Parametric study of friction stir spot welding of aluminium alloy 5754  

Directory of Open Access Journals (Sweden)

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

D. Klob?ar

2014-01-01

364

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

International Nuclear Information System (INIS)

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

365

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

366

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

367

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

International Nuclear Information System (INIS)

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

368

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

Science.gov (United States)

In the present work, scanning and transmission electron microscopy were used to investigate the microstructural evolution occurring during the hydrostatic extrusion of an age-hardenable aluminium alloy. It was shown that processing by hydrostatic extrusion leads to grain refinement to 95 nm in equivalent diameter. Hydrostatic extrusion also influences the geometrical parameters of two different types of particle: intermetallic inclusions and precipitates. The intermetallic inclusions slightly decrease in mean equivalent diameter, but their size remains at the micrometre level. The precipitates are fragmented to nanoscale spherical particles, and their evolution delays the process of grain refinement. PMID:17100901

Lewandowska, M

2006-10-01

369

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

Directory of Open Access Journals (Sweden)

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

N. FATCHURROHMAN

2012-04-01

370

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

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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...

Lackova?, P.; Burs?a?k, M.; Kvac?kaj, T.; Halama, M.

2015-01-01

371

Bending Properties of Locally Laser Heat Treated AA2024-T3 Aluminium Alloy  

Science.gov (United States)

The bending properties of AA2024-T3 aluminium alloy after localized laser assisted softening have been studied and compared to untreated material. Single and multi-path laser scanning strategies are applied for achieving a predictable and minimized springback. Process parameters for softening have been chosen based on FE modeling. In order to investigate the softening, and to characterize the size of this softened region, hardness measurements were carried out. Using a triple scanning path strategy springback was reduced by about 43% without changing the bending radius.

Mohammadi, Amirahmad; Vanhove, Hans; Van Bael, Albert; Duflou, Joost R.

372

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

373

Atomic absorption determination of beryllium in light alloys based on aluminium and magnesium  

International Nuclear Information System (INIS)

The method of atomic-absorption determination of beryllium (nx10-4-10-1% in mass) in light alloys on the basis of aluminium and magnesium, dissolved in HCl using graphite atomizer, has been developed. Conditions of electrothermal atomization of beryllium from hydrochloric acid solutions are as follows: drying for 20 s at 100 deg, thermal decomposition for 20 s at 650 deg,atomization for 7 s at 2600 deg. It is established, that 0.06-0.6 M HCl do not affect beryllium absorption ability. It is found, that Al gives a considerable background signal, increasing the analytical signal of beryllium. Magnesium practically does not affect beryllium absorption

374

Extraction-chromatographic determination of rare earths in alloys on the base of aluminium, containing scandium  

International Nuclear Information System (INIS)

Extraction-chromatographic behaviour of rare earths, scandium and aluminium has been studied in extraction systems of tributylphosphate - HNO3 and di-(2-ethylhexyl)-phosphoric acid - HCl with the aim to choose the conditions of their separation. The chemical yield of scandium and terbium determined by the method of labelled atoms was for scandium of 90+-3% and for terbium of 88+-2%. The yield of rare earths lighter than terbium was less than 80%. While analyzing alloys containing yttrium, terbium or heavier rare earths, tributylphosphate should be used as extragent, and in case of rare earths lighter than terbium di-(2-ethylhexyl)-phosphoric acid should be used

375

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

Science.gov (United States)

A rapid chelatometric method for the determination of Al (4-20%) in magnesium, copper and chromium-aluminium-iron alloys is proposed. HEDTA is used as titrant and Zn solution as back-titrant, with hydrazidazol as indicator. Mn(II), Cu(II), Cd, Zn, Pb, Co(II), Ni, Hg(II), Fe(III), Bi, Cr(III), Sb(III), Ce(III), La, Sn(IV), Ti(IV), Zr and Mo(VI) do not interfere. High selectivity is achieved by a combination of group separation, masking and interference correction. The coefficient of variation varies from 0.2 to 1%. PMID:18963965

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

1985-12-01

376

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

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

Siwiec, G.; Mizera, J.; Jama, D.; Szmal, A.; Burdzik, R.

2014-01-01

377

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

Directory of Open Access Journals (Sweden)

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

G. Siwiec

2014-04-01

378

Supersonic laser spray of aluminium alloy on a ceramic substrate  

International Nuclear Information System (INIS)

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

379

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.

380

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

Energy Technology Data Exchange (ETDEWEB)

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

Pardo, A., E-mail: anpardo@quim.ucm.es [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Casajus, P.; Mohedano, M.; Coy, A.E.; Viejo, F. [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Torres, B. [Departamento de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, 28933 Mostoles, Madrid (Spain); Matykina, E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

2009-05-15

 
 
 
 
381

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

382

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

International Nuclear Information System (INIS)

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

383

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.

384

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

385

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

386

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

387

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

International Nuclear Information System (INIS)

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

388

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

Directory of Open Access Journals (Sweden)

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

Olugbenga A. Omotosho

2012-04-01

389

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

Directory of Open Access Journals (Sweden)

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

A. Czulak

2007-01-01

390

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

391

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

392

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

International Nuclear Information System (INIS)

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

393

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

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The capability of Kelvin probe force microscopy (KFM) to detect and locate hydrogen in corroded 2024 aluminium alloy was demonstrated. Hydrogen was introduced inside the 2024 alloy following a cyclic corrosion test consisting of cycles of immersion in 1 M NaCl solution followed by exposure to air at -20 °C. The combination of scanning electron microscopy, secondary ion mass spectrometry and KFM demonstrated that the grain and subgrain boundaries were preferential pathways for the short-circu...

Larignon, Ce?line; Alexis, Joe?l; Andrieu, Eric; Lacroix, Loi?c; Odemer, Gre?gory; Blanc, Christine

2013-01-01

394

Loss of aluminium during the process of Ti-Al-V alloy smelting in a vacuum induction melting (VIM) furnace  

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In the present paper, results of the study on changes in basic Ti-6Al-4V alloy component contents during smelting in the vacuum induction melting (VIM) furnace are presented. The experiments were performed at 5 – 1 000 Pa and 1 973–2 023 K. Assuming that the observed loss of aluminium from the alloy during smelting is the effect of evaporation, an additional thermodynamic analysis was performed aimed at determining evaporation coefficients.

Blacha, L.; Siwiec, G.; Oleksiak, B.

2013-01-01

395

Loss of aluminium during the process of Ti-Al-V alloy smelting in a vacuum induction melting (VIM furnace  

Directory of Open Access Journals (Sweden)

Full Text Available In the present paper, results of the study on changes in basic Ti-6Al-4V alloy component contents during smelting in the vacuum induction melting (VIM furnace are presented. The experiments were performed at 5 – 1 000 Pa and 1 973–2 023 K. Assuming that the observed loss of aluminium from the alloy during smelting is the effect of evaporation, an additional thermodynamic analysis was performed aimed at determining evaporation coefficients.

L. Blacha

2013-07-01

396

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.)

397

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Hautakangas, S.; Schut, H. [Faculty of Applied Physics, section NPM2, Delft University of Technology, Mekelweg 15, 2629 JB, Delft (Netherlands); Zwaag, S. van der; Rivera Diaz del Castillo, P.E.J. [Faculty of Aerospace Engineering, Section Fundamentals of Advanced Materials, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands); Dijk, N.H. van [Faculty of Applied Physics, Section FAME, Delft University of Technology, Mekelweg 15, 2629 JB, Delft (Netherlands)

2007-07-01

398

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

399

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.

400

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

International Nuclear Information System (INIS)

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

 
 
 
 
401

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

402

Surface modification of 2014 aluminium alloy-Al2O3 particles composites by nickel electrochemical deposition  

International Nuclear Information System (INIS)

A method to modify the surface of aluminium matrix composites (AMC) by electrochemical nickel deposition has been developed. Deposition was carried out in a stirred standard Watt's bath, whereas potential and time were varied to optimize coating characteristics. The method, that allowed to overcome the serious difficulties associated to electrochemical deposition of an inherently inhomogeneous material, was used to nickel coat composites of 2014 aluminium alloy-15 vol.% Al2O3 particles. Coats with a good adherence and up to 60 ?m thick were easily obtained. In order to improve surface properties, the coated composite was subjected to rather long (from 10 to 47.5 h) heat treatments at a temperature of 520 deg,C. The heat treatments improved the uniformity of the deposited layer and promoted the formation of Al-Ni intermetallics (mainly Al3Ni2, as revealed by X-ray diffraction and energy-dispersive X-ray analysis (EDX)). Experimental results indicate that growth of the intermetallic layer is diffusion limited

403

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-09-01

404

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

Directory of Open Access Journals (Sweden)

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

M. Adamiak

2005-12-01

405

Determination of nitrogen, oxygen, fluorine, phosphorus, sulfur and chlorine in aluminium alloys by means of neutron activation  

International Nuclear Information System (INIS)

N, O, F, P, S, Cl can be mixed with aluminium during electrolysis, alloying operations and surface treatments. These elements allow changes in mechanical properties. The authors have adapted separation methods to neutron activation analysis of aluminium alloys down to the sub-ppm level. N, F, Cl determinations need distillation. S and P separations are based on liquid extraction. O determination is carried out by instrumental method. Tracers and inactive carriers are used for separation study. The cleaning of the surface is performed if necessary. 14 MeV neutron activation is applied to nitrogen, oxygen and fluorine determination. The sensitivity is about 200 imp/min/mg. Reactor neutron activation is performed for phosphorus, sulfur and chlorine analysis. The detection level is 0.1 ?g/g. Interesting differences of N, O, F and Cl contents are observed for Al-Zn or Al-Cu alloys in the range of 0.1-10 ?g/g. (author)

406

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

407

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

Directory of Open Access Journals (Sweden)

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

?. Kaczmarek

2009-12-01

408

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

409

Experimental Evaluation of Springback in Aluminium Alloys Using Optical Measurement and Numerical Analysis  

Science.gov (United States)

The aim of this paper is to establish an efficient and effective means of understanding the springback behaviour of a 5xxx-O and a 6xxx-T61 series aluminium alloy. The tooling used for investigating the springback is a small U-channel stamping draw die using two die radii of 8 or 12 mm and a punch radius of 12 mm. The samples were drawn to depths of 50 or 75 mm with a minimum of 5 samples being drawn for each condition. The U-channel samples were then evaluated using an optical scanning technique and the springback values were calculated using a numerical analysis as developed by one of the authors. The comparison of the sidewall springback, sidewall curl and flange springback under different conditions is conducted and the effect of the draw depth and die radius on the final springback is shown. Statistical analyses of both the drawing condition and the scanning technique are conducted to understand the effect of process variation on the results obtained. The 6xxx series shows higher springback values when compared to 5xxx series alloy. An increase in drawing depth suggests higher springback for both the alloys.

Bhattacharya, R.; Stanton, M.; Dargue, I.; Aylmore, R.; Williams, G.

2011-05-01

410

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

International Nuclear Information System (INIS)

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

411

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.)

412

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)

413

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

414

Electron microscopic study on interfacial characterization of electroless Ni-W-P plating on aluminium alloy  

International Nuclear Information System (INIS)

The interface between electroless plating Ni-W-P deposit and aluminium alloy (Al) matrix at different temperature heated for 1 h was studied using transmission electron microscope. The results show that the interface between as-deposited Ni-W-P deposit and Al matrix is clear. There are no crack and cavity. The bonding of Ni-W-P deposit and Al matrix is in good condition. The Ni-W-P plating is nanocrystalline phase (5-6 nm) in diameter. After being heated at 200 deg. C for 1 h, the interface of Ni-W-P deposit and Al matrix is clear, without the appearance of the diffusion layer. There exist a diffusion layer and educts of intermetallic compounds of nickle and aluminium such as Al3Ni, Al3Ni2, NiAl, Ni5Al3 and so on between Ni-W-P deposit and Al matrix after being heated at 400 deg. C for 1 h

415

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

416

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

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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

417

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

International Nuclear Information System (INIS)

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

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

Energy Technology Data Exchange (ETDEWEB)

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

Cabibbo, Marcello, E-mail: m.cabibbo@univpm.it [Dipartimento di Ingegneria Meccanica e Scienze Matematiche (DIISM), Università Politecnica delle Marche, 60131 Ancona (Italy)

2013-09-15

419

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

Science.gov (United States)

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

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

2006-08-01

420

Microscopic study of 5083-H321 Aluminium alloy under fretting fatigue condition  

International Nuclear Information System (INIS)

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