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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)

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

2010-01-01

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)

[en] 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)[pt] Estuda-se o processo de corrosao da liga de aluminio AA5052 isotermicamente nas temperaturas de 400C, 600C, 800C, 900C, 1400C, 2000C e 2800C, em agua deionizada. Os metodos utilizados para este estudo sao, atraves de pesagens periodicas dos corpos-de-prova, de analises por ativacao neutronica dos produtos da corrosao dissolvidos na agua, de analises termogravimetrica e termodiferential, de analises por difracao de raios-X e de observacoes metalograficas dos cristais produzidos no processo da corrosao, com o auxilio de microscopia otica com luz polarizada e microscopia eletronica de varredura. Calculam-se as energias de ativacao para a corrosao aquosa da liga de aluminio e para a dissolucao dos produtos de corrosao em agua deionizada. (ARHC)

1980-01-01

3

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

International Nuclear Information System (INIS)

[en] 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

2008-01-15

4

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

International Nuclear Information System (INIS)

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

2005-01-01

5

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

International Nuclear Information System (INIS)

[en] 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

2008-03-15

6

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

International Nuclear Information System (INIS)

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

2005-01-01

7

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

International Nuclear Information System (INIS)

[en] 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

2004-11-15

8

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 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 soldagem denominado Friction Stir Welding (FSW) tem recebido atenção por suas potencialidades onde o aporte de calor deve ser minimizado ou quando metais dissimilares deve (more) m 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 minimiz (more) ed 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 elon

Capelari, Tiago Valdameri; Mazzaferro, José Antônio Esmerio

2009-09-01

9

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

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

Tiago Valdameri Capelari; José Antônio Esmerio Mazzaferro

2009-01-01

10

Soldering of aluminium alloys  

International Nuclear Information System (INIS)

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

1980-01-01

11

Hydrogen generation from aluminium corrosion in reactor containment spray solutions  

International Nuclear Information System (INIS)

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

1982-01-01

12

Extrusion of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

Sheppard, T.

1999-01-01

13

Substructure strengthening in aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The evolution in microstructure has been investigated for several aluminium alloys; AlMg0.5, AlMg1, AlMg3, AA1050, AA3004 and AA3207. The materials were deformed by tensile testing, hot torsion, uniaxial compression, plane strain compression and cold rolling. A transmission electron microscope was utilized in the quantification of subgrain/cell size and dislocation density. The experimental data have been compared to the predictions of a three-parameter work-hardening model. The model predicts the substructure evolution and strengthening quite well. (orig.)

Nord-Varhaug, K.; Forbord, B.; Benestad, J.; Pettersen, T.; Roenning, B.; Marthinsen, K. [Norwegian Univ. of Sci. and Technol., Trondheim (Norway). Dept. of Mater. Technol. and Electrochem.; Bardal, A.; Benum, S.; Nes, E.

2000-07-01

14

Scandium alloying of aluminium copper-containing alloys  

International Nuclear Information System (INIS)

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

1995-01-01

15

Radiation damage of aluminium alloy SAV-1  

International Nuclear Information System (INIS)

The present work is the continuation of studies of radiation damage of aluminium alloy SAV-1. the alloy is the material of spent rod of automatic regulation of research reactor WWR-K. Aim of the work is specification of processes responsible for specific electric resistivity change

2005-01-01

16

Mechanical alloying of aluminium-lithium-magnesium alloy powders  

Energy Technology Data Exchange (ETDEWEB)

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 AlLiH/sub 4/ 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.

Layous, A.; Nadiv, S.; Lin, I.J.

1987-01-01

17

Prospects in alloying of aluminium alloys with scandium  

Energy Technology Data Exchange (ETDEWEB)

Prospects of alloying of some aluminium alloys used in critical welded and non-welded constructions with scandium are under discussion. Scandium addition is shown to make casting material structure much more fine, to increase recrystallization temperature of deformed semifinished items and to improve the strength properties, stress corrosion resistance, and weldability. An analysis of peculiarities of scandium solid solution decomposition in aluminium ingots is performed and principles of the fabrication of deformed semifinished items are formulated.

Elagin, V.I.; Zakharov, V.V.; Rostova, T.D.

1982-12-01

18

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

2009-01-01

19

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 TEM)in 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(FeMn)3Si, 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.

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

2007-01-01

20

Corrosion behaviour of physical vapour deposition aluminium-based coatings on 2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Pure aluminium and Al-Li coatings applied by physical vapour deposition on 2024 aluminium alloy were tested for their corrosion properties. It was concluded that both the effects of self-dissolution of the coating and cathodic protection should be considered in the assessment. The results favour the use of pure aluminium instead of Al-Li alloy. (orig.).

Salvador Fernandes, J.C.; Ferreira, M.G.S. (Dept. de Engenharia Quimica, Inst. Superior Tecnico, Lisbon (Portugal))

1992-05-20

 
 
 
 
21

Argon-arc welding of heat resisting aluminium alloys  

International Nuclear Information System (INIS)

Welding of aluminium heat resisting alloys of the Al-Cu-Mg system is studied. The hot-shortness of heat-resistant alloys M40, 1150 and 1151 are at the level of aluminium alloys 1201 and by 2-3 times lower as compared to the aluminium alloy AMg6. The M40, 1150 and 1151 alloys have unquestionable advantages against other know aluminium alloys only at temperatures of welded structures operation, beginning with 150-2000 deg C and especially at 250 deg C

22

Electroslag welding of medium aluminium-magnesium alloy  

International Nuclear Information System (INIS)

Presented are the results of investigation on weldability of an aluminium-magnesium alloy of 50 mm thick during electroslag welding by strip electrode. The test data on welded joints at room and at negative temperatures are presented. It is shown, that the alloying of strip aluminium-magnesium electrodes with zirconium provides high strength welded joints. The electrodes should be applied for short electroslag welding seams in welded constructions fabricated of the aluminium-magnesium alloy

1979-01-01

23

Ti cladding and Ni alloying on pure aluminium and aluminium alloys by an electron beam technique  

International Nuclear Information System (INIS)

Alloying and cladding treatments have been performed on pure aluminium and a 5%Si-3% Cu-Mg Al-based alloy by an electron beam technique. Metal sheets of Ti-6Al-4V alloy and pure nickel were used for cladding and alloying respectively. In both cases the sheets were mechanically clamped on the substrate. In the cladding process, a thin layer of substrate only a few tens of microns thick was affected by the melting process. In the alloying process, melting and solidification of the Ni overlayer with a controlled amount of substrate lead to a significant modification of the surface microstructure and microhardness. (orig.)

1993-08-03

24

Fluidity of Aluminium Foundry Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The fluidity of an alloy plays a key role for the foundry and transport industries as it affects the quality and soundness of the cast products. Particularly, fluidity influences the reject rates, hence casting costs and the production of thinwalled, hence light components. Fluidity is a complex tec...

Di Sabatino, Marisa

25

Precipitate strengthening of nanostructured aluminium alloy.  

UK PubMed Central (United Kingdom)

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.

Wawer K; Lewandowska M; Kurzydlowski KJ

2012-11-01

26

FSW characterization of 6082 aluminium alloys sheets  

Directory of Open Access Journals (Sweden)

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

K. Mroczka; A. Pietras

2009-01-01

27

Scientific principles of making an alloying addition of scandium to aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Research works concerning making an alloying addition of scandium to aluminium alloys are carried out for nearly 30 years in Russia. As a result of these studies, main regularities characterising the effect of scandium on a structure and properties of aluminium alloys have been found and, based on this, principles of making an alloying addition of scandium to aluminium alloys and foundations of a technology for production of wrought semiproducts have been formulated. (orig.)

Davydov, V.G.; Rostova, T.D.; Zakharov, V.V.; Filatov, Y.A.; Yelagin, V.I. [All-Union Inst. of Light Alloys, Moscow (Russian Federation)

2000-03-15

28

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; M. Krupi?ski; T. Ta?ski

2012-01-01

29

Disagglomeration in thixoformed wrought aluminium alloy 2014  

International Nuclear Information System (INIS)

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

2005-02-15

30

Aluminium alloys in municipal solid waste incineration bottom ash.  

Science.gov (United States)

With the increasing growth of incineration of household waste, more and more aluminium is retained in municipal solid waste incinerator bottom ash. Therefore recycling of aluminium from bottom ash becomes increasingly important. Previous research suggests that aluminium from different sources is found in different size fractions resulting in different recycling rates. The purpose of this study was to develop analytical and sampling techniques to measure the particle size distribution of individual alloys in bottom ash. In particular, cast aluminium alloys were investigated. Based on the particle size distribution it was computed how well these alloys were recovered in a typical state-of-the-art treatment plant. Assessment of the cast alloy distribution was carried out by wet physical separation processes, as well as chemical methods, X-ray fluorescence analysis and electron microprobe analysis. The results from laboratory analyses showed that cast alloys tend to concentrate in the coarser fractions and therefore are better recovered in bottom ash treatment plants. PMID:19423581

Hu, Yanjun; Rem, Peter

2009-05-07

31

Aluminium alloys in municipal solid waste incineration bottom ash.  

UK PubMed Central (United Kingdom)

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

Hu Y; Rem P

2009-05-01

32

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; A. Sládek; M. Br?na

2010-01-01

33

Solidification microstructures of aluminium-uranium alloys  

International Nuclear Information System (INIS)

[en] 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[pt] Examinam-se as microestruturas de solidificacao de ligas aluminio-uranio, com teores de 4 a 20% U, obtidos por solidificacoes convencional e unidirecional. Procura-se verificar quais as condicoes para formacao dos cristais primarios e do eutetico para o sistema Al-UAl4, e analisar a influencia das variaveis sobre a estrutura obtida. Estuda-se o efeito da velocidade de resfriamento sobre as estruturas das ligas, principalmente as de composicoes euteticas (13%U) e hipereuteticas (acima de 13%U). Analisa-se os efeitos da velocidade de crescimento e do gradiente termico no liquido. Mostra-se que as estruturas podem ser analisadas utilizando-se o conceito cinetico de regiao de crescimento conjunto 'coupled zone'. Sugere-se a localizacao qualitativa do intervalo de composicoes e temperaturas no qual se tem crescimento eutetico

1976-01-01

34

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

Scientific Electronic Library Online (English)

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

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

2009-12-01

35

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

36

Studies on reactions between aluminium/aluminium alloy and molten sodium  

Energy Technology Data Exchange (ETDEWEB)

In this research, reactions between pure aluminium/its alloy and molten sodium at 350{proportional_to}450 C have been investigated. Optical microscopy and X-ray diffraction analysis were used to observe and analyze the morphology, the distribution and the growth kinetic mechanism of corrosion products. Experiments showed that corrosion severity of specimens from molten sodium was related to the content of silicon in aluminium, and that corrosion of aluminium-silicon alloys in molten sodium was a diffusion-controlled solid-state reaction. (orig.)

Xijiang, L.; Xiong, R.; Pengcheng, S.; Di, Z. [Shanghai Jiao Tong Univ. (China). Sch. of Mater. Sci. and Eng.

2000-03-15

37

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

International Nuclear Information System (INIS)

[en] 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)

1966-01-01

38

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.).

1986-01-01

39

Damage tolerance of aluminium alloys in aircraft applications  

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-07-01

40

Corrosion and filming behaviour of aluminium and its alloys  

Energy Technology Data Exchange (ETDEWEB)

Assisted largely by transmission electron microscopy of revealing specimens, produced by materials` ultramicrotomy, the influence of impurities in aluminium on the location of anodic and cathodic sites during corrosion of aluminium and conversion coating development is explored. The role of deliberate alloying additions is also revealed. In situations where aluminium is consumed to develop anodic oxides at high current efficiency, the influence of alloying elements on the overall growth process is shown. Of particular importance is the observation of fine scale interfacial enrichments of alloying elements over distances of about 2 nm beneath the anodic oxide film. After achieving a steady-state enrichment level, oxidation of the alloying element proceeds with subsequent migration across the anodic film under the action of the intense field. (orig.)

Thompson, G.E. [University of Manchester Inst. of Science and Technology (United Kingdom). Corrosion and Protection Centre Industrial Services

1996-11-01

 
 
 
 
41

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The recycling of aluminium from used aluminium scrap leads to an unavoidable presence of pollutions in the form of elements of various amounts. Two such elements are iron and silicon. These will always be present to some extent in an aluminium alloy as they are introduced to the alloy during process...

Slagsvold, Marius

42

Behaviour of hydrogen impurity in aluminium alloys during anodizing  

International Nuclear Information System (INIS)

[en] 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

2003-01-31

43

Aluminium powder metallurgical alloys; Aluminium funmatsu yakin gokin  

Energy Technology Data Exchange (ETDEWEB)

This article reviews recent studies on the aluminum powder metallurgical alloys. Recently, design of alloys, which have not been able to be made by the conventional melting processes, has become to be enable by using the rapidly solidified powder metallurgical techniques. By combining these with various processing methods, expansion of usage of powder metallurgical products is expected. Among these, the aluminum alloy attracts attention as one of the typical new materials. For the aluminum powder metallurgy, the alloy development by utilizing non-equilibrium phase, gas atomizing process in mass production technology of rapidly solidified aluminum powder, production technology of composites of pelletizing powders and ceramic powders, and aluminum-based materials used for automobiles attract attention. Additionally, researches are proceeded, as for the molding and solidification by powder production process, powder extrusion process and powder forging process, the spray forming, the mechanical alloying and reaction sintering, the structure and characteristics, etc.

Kono, T. [Mitsubishi Materials Corp., Tokyo (Japan)

1994-08-15

44

Electrodeposition of aluminium, aluminium/magnesium alloys, and magnesium from organometallic electrolytes  

Energy Technology Data Exchange (ETDEWEB)

The electrodeposition of aluminum, magnesium, and the combination of these metals from nonaqueous media is discussed. Plating baths for depositing Al/Mg alloys or for plating essentially pure Mg were developed. These solutions contain alkali meal fluoride or quaternary ammonium halide/aluminium alkyl complexes and dialkyl magnesium dissolved in aromatic hydrocarbons. Alloy deposits over the whole composition range can be plated from these solutions by varying the relative quantities of the aluminium and magnesium alkyls and by changing the bath-operating parameters. 18 refs., 4 figs.

Mayer, A.

1988-01-01

45

Selecting of aluminium casting alloys for plasmochemical ceramic coatings  

Energy Technology Data Exchange (ETDEWEB)

The selecting of aluminium casting alloys for producing the wear resistance structural materials with plasmochemical ceramic coating was considered. It was shown that ceramic coatings formed on commercial Al-Si alloys of 3xx series (>5%Si) have a low quality because of the substantial influence of silicon particles. So it was proposed to use the new casting aluminium alloys of eutectic type with an increased content on transition metals (Ni, Fe, Ce, Mn, Zr, Cr), where the second phases in the eutectics are: Al{sub 3}Ni, Al{sub 4}Ce, Al{sub 9}FeNi, Al{sub 10}CeFe{sub 2}, Al{sub 8}Fe{sub 2}Si, Al{sub 15}(Fe,Mn){sub 2}Si{sub 3} and others. The thickness and microhardness of coatings formed on the new alloys were found considerably higher comparing with commercial Al-Si alloys. (orig.)

Belov, N.A.; Zolotorevskiy, V.S. [Moscow Inst. of Steel and Alloys, Moscow (Russian Federation); Shatrov, A.S. [Keronite Ltd., Abington, Cambridge (United Kingdom)

2002-07-01

46

Aluminium and its alloys: weldability, welding metallurgy; L'aluminium et ses alliages: soudabilite, metallurgie du soudage  

Energy Technology Data Exchange (ETDEWEB)

The aim of this book is to give technological and use elements of the welding processes as well as the knowledge in weldability and metallurgy required for a better control of the welding of aluminium alloys. In the first part are detailed the generalities on aluminium alloys, their properties and uses sectors. The bases of the physical metallurgy of the aluminium alloys are dealt with too. The second part concerns the welding and the related techniques as well as the properties of the assemblies. Several supplements give useful data for the construction with aluminium alloys. This book is particularly devoted to engineers and technicians using or having to use for the first time the welding of aluminium alloys. (O.M.)

Boucher, Ch.

2000-07-01

47

Research about the properties of aluminium-lithium alloy  

International Nuclear Information System (INIS)

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

1988-01-01

48

Studies of the superplasticity of a high strength aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

A high strength Aluminium-Magnesium-Zirconium alloy was thermo mechanically treated to develop ultra fine grain size. The effect of thermo mechanical treatment (TMT) on grain refinement and super-plasticity was studied. Both optical and electron microscopy were used in the study of microstructure and fracture. It is concluded that ultra fine grain size can be developed by cyclic TMT including high levels of superplasticity in this alloy. Results are discussed in detail in the paper. (orig.).

Mehta, S.; Sengupta, P.K.; Iyer, K.J.L.; Nair, K. (HAL, Bangalore (India))

1992-03-01

49

Effect of Low Strain Rate on Formability of Aluminium Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Effect of low strain rate on formability of aluminium alloy 2014 by means of torsion test was performed. The presented experimental results exhibit decrease of the ductility with increase and decrease of ?? and T, respectively, and optimal values of , ?? T are thus obtained.

Bidulská, J.; Kva?kaj, T.; Bidulský, R.; Cabbibo, M.; Evangelista, E.

2007-01-01

50

Mixed-mode fatigue crack growth behaviour in aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fatigue crack propagation tests in compact mixed-mode specimens were carried out for several stress intensity ratios of mode I and mode II, KI/KII, in AlMgSi1-T6 aluminium alloy with 3 mm thickness. The tests were performed in a standard servo-hydraulic machine. A linkage system was developed in ord...

Borrego, L. P.; Antunes, F. V.; Costa, J. M.; Ferreira, J. M.

51

Structure analysis of 3104 aluminium alloy applied to deep drawing  

Energy Technology Data Exchange (ETDEWEB)

Optical and electron microscopy observations and X-ray investigations of 3104 aluminium alloy ingots and bands after experimental heat treatment were carried out. The influence of ingots homogenisation temperature and parameters of material heat treatment after hot rolling on structure, texture and earing of band 0.3 mm thick was analysed. (orig.)

Klyszewski, A.; Lech-Grega, M.; Zelechowski, J.; Szymanski, W. [Light Metals Div., Skawina (Poland). Inst. of Non-Ferrous Metals

2000-07-01

52

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Scientific Electronic Library Online (English)

Full Text Available 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 crystal orientation is a difficult task. The present work was undertaken to analyse the texture by X-ray diffraction techniques, of three spray formed hypereutectic Al-Si alloys. (more) 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.

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

2005-06-01

53

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

CERN Document Server

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

International Organization for Standardization. Geneva

1996-01-01

54

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

International Nuclear Information System (INIS)

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

1978-01-01

55

Statistical analysis of pit propagation rate in pure aluminium and 2024 aluminium alloy  

International Nuclear Information System (INIS)

[en] The susceptibility to pit propagation in pure aluminium and 2024 alloy was investigated in sulphate-and-chloride-containing solutions. In the same experimental conditions, the values of the propagation rate measured for different pits were very scattered. So, a statistical analysis was used to evaluate a mean pit propagation rate. The mean pit propagation rate varied linearly with the logarithm of the chloride concentration allowing a critical chloride concentration, below which pits did not propagate, to be determined. The influence of the applied polarisation potential on the mean pit propagation rate showed two different types of behaviour for pure aluminium and 2024 alloy resulting from the presence of coarse copper-and-magnesium-rich particles in the latter. (orig.)

1998-01-01

56

Statistical analysis of pit propagation rate in pure aluminium and 2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

The susceptibility to pit propagation in pure aluminium and 2024 alloy was investigated in sulphate-and-chloride-containing solutions. In the same experimental conditions, the values of the propagation rate measured for different pits were very scattered. So, a statistical analysis was used to evaluate a mean pit propagation rate. The mean pit propagation rate varied linearly with the logarithm of the chloride concentration allowing a critical chloride concentration, below which pits did not propagate, to be determined. The influence of the applied polarisation potential on the mean pit propagation rate showed two different types of behaviour for pure aluminium and 2024 alloy resulting from the presence of coarse copper-and-magnesium-rich particles in the latter. (orig.) 8 refs.

Blanc, C.; Mankowski, G. [Ecole Nat. Superieure de Chimie, Toulouse (France). Lab. des Materiaux

1998-12-31

57

Frictional characteristics of nano-embedded aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

We report the friction and wear behaviour of nano-embedded aluminium alloys consisting of nanosized lead dispersoids in aluminium matrix. These alloys are synthesized by rapid solidification processing technique. Sliding wear tests have been conducted on both the as-cast and melt-spun ribbons using pin on disc set up. Normal loads used range from 0.5 kgf to 4.0 kgf. Characterization of melt-spun alloys and worn pin surface is done by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) and transmission electron microscopy (TEM). Our results on friction studies suggest a significant reduction in the coefficient of friction values for all alloys tested in air. The frictional properties are better than as cast alloys of similar composition prepared by Stir Casting as well as magnetohydrodynamic technique where the dispersions are of micron size. We attempt explaining our results on friction and wear using the available theoretical understanding and the knowledge of the microstructure of these alloys. (orig.)

Bhattacharya, V.; Chattopadhyay, K. [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy

2001-07-01

58

On the abrasive-corrosive wear of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The performance of a range of aluminium alloys in abrasive-corrosive wear conditions which simulate those encountered in mining environments has been investigated. Wear processes are identified and the influences of material properties and microstructure are examined. Cast alloys, which show poor microfracture properties as a result of coarse and brittle phases, have poor dry abrasion resistance. Heat-treatable alloys with good combinations of hardness, strength and toughness, which provide improved resistance to surface deformation and microfracture, have improved abrasion resistance. In aqueous solutions which simulate corrosive mine waters the aluminium alloys show isolated pitting attack through to severe pitting, localized attack and general corrosion depending upon the composition, size and dispersion of microconstituents. The presence of cathodic copper-, silicon- and iron-rich regions is particularly deleterious. Under wear conditions comprising abrasive and corrosive intervals, performance is determined by both mechanical and electrochemical properties, the importance of which will be determined by their relative severities and times of exposure. A compromise of the abrasive and corrosive resistance has to be made in order to make the optimum alloy selection. For the conditions used in the laboratory test the alloys 7017, 7075, 5083 and 5251 provide the best wear resistance. (orig.).

Meyer-Rodenbeck, G.; Hurd, T.; Ball, A. (Dept. of Materials Engineering, Univ. Cape Town (South Africa))

1992-05-01

59

LASER CLADDING ON ALUMINIUM BASE ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

laser cladding is often performed on iron or titanium base alloys. In the present work, this method is employed on aluminum alloys ; nickel or silicon are added by powder injection. Addition of silicon leads to sound surface layers, but with moderated properties, while the presence of nickel induces...

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

60

New developments in aluminium alloys for electrical applications; Les progres dans les alliages d'aluminium a usages electriques  

Energy Technology Data Exchange (ETDEWEB)

Traditionally, pure aluminium 1370 is used for ACSR overhead lines and insulated cables and 6000 family alloys, also known as Almelec, are used for AAAC. Energy producers and operators have been facing new environmental and regulatory constraints for the last few years. They include line burial and increasing the current carrying capacity of conductors. New alloys have been developed to meet this demand and are discussed here. They are: high-conductivity 6000 alloys, compact conductors and aluminium-zirconium alloys. Moreover advances in aluminium smelting technology have made it possible to decrease impurity content and thus increase conductivity. The use of purer aluminium variants is cost-effective for HTA and HTB cables. (authors)

Cottignies, L. [Pechiney, Centre de Recherches de Voreppe, 38 (France); Loreau, B. [Aluminium Pechiney, 75 - Paris (France)

2001-10-01

 
 
 
 
61

Evaluation of femtosecond LIBS for spectrochemical microanalysis of aluminium alloys.  

UK PubMed Central (United Kingdom)

The analytical performance of femtosecond laser-induced breakdown spectroscopy (LIBS) for elemental microanalysis of aluminium alloys and for mapping precipitate distribution on the sample surface has been studied in detail. A Ti-sapphire laser system producing pulses of 130 fs at 800 nm was used to generate the laser-induced plasma. Multi-element microanalysis of commercially available aluminium alloys was performed in air at atmospheric pressure. Crater characteristics such as diameter and crater morphology were characterized by optical and scanning-electron microscopy. Scaling of plasma emission and limit of detection as a function of laser pulse energy was also investigated. Current experimental results are presented and are compared with previous nanosecond microLIBS measurements.

Cravetchi IV; Taschuk MT; Tsui YY; Fedosejevs R

2006-05-01

62

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

63

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

64

Performance and reliability of aluminium casting alloys for wheels  

Energy Technology Data Exchange (ETDEWEB)

The influence of different casting parameters on the quality of aluminium cast wheels is reviewed. The effects of alloy chemical composition, structure fineness, soundness and cleanness are described. Special attention is paid to metal quality where gas and inclusions have to be carefully controlled. Some examples of predicting the formation of shrinkage defects or oxide formations during filling and solidification of a cast wheel with appropriate simulation software are presented.

Garat, M.; Laslaz, G.; Laty, P.; Perrier, J.J. (Aluminium Pechiney, Voreppe (France))

1991-05-01

65

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

International Nuclear Information System (INIS)

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

1995-01-01

66

Permeation behavior of deuterium implanted into aluminium-lithium alloys  

International Nuclear Information System (INIS)

[en] Ion implantation driven permeation (IDP) behavior has been investigated for deuterium implanted with low energy (100-1800 eV) into aluminium-lithium alloys (Al-0.89wt.%Li and Al-2.22wt.%Li alloys) to simulate the behavior of tritium. The experimental results showed that the steady state IDP behavior for Al-Li alloys was divided into two temperature regions around 620 K for 0.89wt.%-Li alloy and 700 K for 2.22wt.%-Li alloy. In the high temperature regions, the IDP fluxes through both alloys depended significantly on the temperature, while the IDP fluxes were almost constant in the low temperature regions. This fact would suggest that the change in the above temperature dependencies are attributed to the hange of the chemical trap site in alloys, because the temperatures at the turning point of the temperature dependencies coincide with those at the phase transition from ? + ? phase. (orig.)

1992-01-01

67

Permeation behavior of deuterium implanted into aluminium-lithium alloys  

Energy Technology Data Exchange (ETDEWEB)

Ion implantation driven permeation (IDP) behavior has been investigated for deuterium implanted with low energy (100-1800 eV) into aluminium-lithium alloys (Al-0.89wt.%Li and Al-2.22wt.%Li alloys) to simulate the behavior of tritium. The experimental results showed that the steady state IDP behavior for Al-Li alloys was divided into two temperature regions around 620 K for 0.89wt.%-Li alloy and 700 K for 2.22wt.%-Li alloy. In the high temperature regions, the IDP fluxes through both alloys depended significantly on the temperature, while the IDP fluxes were almost constant in the low temperature regions. This fact would suggest that the change in the above temperature dependencies are attributed to the hange of the chemical trap site in alloys, because the temperatures at the turning point of the temperature dependencies coincide with those at the phase transition from [alpha] + [delta] phase. (orig.).

Hayashi, T.; Okuno, K.; Naruse, Y. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan))

1992-09-01

68

Superplastic blow forming of 2219 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Superplasticity in 2219 aluminum alloy was achieved through thermomechanical processing. Tension tests showed that the alloy exhibits superplastic behavior in the temperature range of 450-540 C and strain rates ranging from 2.2 x 10{sup -5} to 1.1 x 10{sup -1} s{sup -1}. A maximum elongation-to-failure of 670% was recorded at 500 C and at the initial strain rate of 2.2 x 10{sup -4} s{sup -1}. High cavitation level and intensive grain growth were observed. Sheet of the 2219 aluminum alloy was blow formed into conical shape using two different methods: simple negative and backpressure forming. A strain of 2.1 was obtained at 500 C under the backpressure blow forming condition. It was found that elongation to failure under blow forming with backpressure is about 1.5 times higher than that under a simple female forming. Microstructural evolution of blow formed parts was also examined. (orig.)

Kaibyshev, R.; Kazakulov, I.; Gromov, D. [Inst. for Metals Superplasticity Problems, Ufa (Russian Federation); Lesuer, D.R.; Nieh, T.G. [Lawrence Livermore National Lab., Livermore, CA (United States)

2004-07-01

69

Serrated flow in aluminium alloys containing lithium  

Energy Technology Data Exchange (ETDEWEB)

Serrated-flow characteristics have been studied in binary Al-Li-alloys with different compositions. Load-elongation curves seem divided into two sections of which the first is weakly, the second heavily, serrated. The initial weak serrations, which diminish with aging, arise probably from the interaction of dislocations with lithium atoms in solid solution. It is proposed that the larger serrations which appear later on the load-elongation curve (if the elongation to necking is large enough to allow them to develop), and which increase in size with progressive aging, are connected with shearable {delta}{prime}-precipitates. The effects of zirconium and magnesium additions to Al-Li-alloys on serrations have also been investigated. These elements do not change the basic mechanisms of serrated flow. However, the apparent activation energies as calculated for the alloy containing magnesium from the onset strains do not make much sense, because two elements contribute now to serrated flow, and the situation becomes complex.

Kumar, S.; Pink, E. [Oesterreichische Akademie der Wissenschaften, Leoben (Austria). Erich-Schmid-Inst. fuer Festkoerperphysik

1997-12-01

70

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

71

Diffusion bonding of superplastic 7075 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Diffusion bonding (DB) of superplastic 7075 Al alloy has been investigated for various temperatures, pressures and times, using a Gleeble 1500 test machine. After the removal of surface oxide, an organic solution was used to protect the surfaces prior to bonding. The strengths achieved after bonding were dependent on interface grain boundary migration and on grain growth during the bonding process. Under optimum conditions, bonds having parent metal shear strength and microstructure were obtained. The optimum temperatures for diffusion bonding, 510-520 C, corresponded with those at which the material exhibited optimum superplastic behavior. The characteristics and mechanisms of bonding are discussed. (orig.) 21 refs.

Huang, Y.; Ridley, N.; Humphreys, F.J.; Cui, J.-Z. [University of Manchester Inst. of Sci. and Technol. (United Kingdom). Mater. Sci. Centre

1999-06-30

72

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; L.A. Dobrza?ski; J. Konieczny

2008-01-01

73

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; A.M. Camacho; J.M. Sánchez-Sola; M. Marcos

2006-01-01

74

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route  

Energy Technology Data Exchange (ETDEWEB)

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 AlCl{sub 3}. 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 AlCl{sub 3} 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 UCl{sub 5} and UCl{sub 6}. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Genie Chimique (LGC), Universite Paul Sabatier, UMR CNRS 5503, 118 route de Narbonne, 31062 Toulouse Cedex 04 (France)

2008-07-01

75

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route  

International Nuclear Information System (INIS)

[en] 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)

2008-01-01

76

Friction stir welding of 6061 aluminium alloy  

International Nuclear Information System (INIS)

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

2009-01-01

77

Failures of dies for die-casting of aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Die-casting dies for casting of aluminum alloys fail because of a great number of different and simultaneously operating factors. Material selection, die design, and thermal stress fatigue generated by the cyclic working process (heat checking), as well as to low and inhomogeneous initial die temperature contribute to the failures and cracks formation on/in dies for die-casting of aluminium alloys. In the frame of the presented investigation work the intensity and homogeneity of the temperature fields on the working surface of the testing die were checked through thermographic measurements, and failures and cracks on the working surface of the die were analysed with non-destructive metallographic examination methods.

Kosec, B.

2008-01-01

78

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.

2011-01-01

79

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

80

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

Directory of Open Access Journals (Sweden)

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

R. Singh

2011-01-01

 
 
 
 
81

Quantitative prediction of solute strengthening in aluminium alloys.  

UK PubMed Central (United Kingdom)

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

Leyson GP; Curtin WA; Hector LG Jr; Woodward CF

2010-09-01

82

Quantitative prediction of solute strengthening in aluminium alloys.  

Science.gov (United States)

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

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

2010-08-01

83

High effective organic corrosion inhibitors for 2024 aluminium alloy  

International Nuclear Information System (INIS)

[en] 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

2007-01-01

84

Modelling hot deformation and textures of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The fundamental mechanisms controlling hot deformation texture formation in aluminium alloys are characterised by high temperature (350-550 ) channel-die compression tests on Al-1%Mn crystals at strain rates up to 10s{sup -1}. It is shown that, depending on the orientation, non-octahedral slip can be activated, usually in association with classical octahedral slip. The particular problem of the stability of cube grains in PSC is addressed in detail. The high temperature, high strain flow stresses of the different families of slip systems are evaluated over 5 decades of strain rate. These flow stresses are used to model hot deformation textures in Al alloys for simple strain paths such as tension, compression and plane strain compression. The good agreement with experimental textures provides a basis for extending the model to complex strain paths encountered in industrial practice. Using finite element data as input, the textures and their through-thickness gradients are simulated for hot extrusion and hot reversible and tandem rolling of commercial alloys. (orig.)

Driver, J.; Maurice, C. [Ecole des Mines de Saint Etienne (France). Dept. of Mater. Process.; Perocheau, F.

2000-07-01

85

Titanium aluminide formation in Ti implanted aluminium alloy  

Science.gov (United States)

Ion implantation has been extensively used for modifying the surfaces of engineering materials. In the present report, the implantation of type 6061 aluminium alloy with Ti ions has been investigated as a function of dose and substrate temperature. Retained doses in the range 0.8-6 × 1017 ions cm-2 were studied in order to examine the effect of Ti concentration on intermetallic compound stoichiometry. The formation of titanium aluminides following implantation was monitored by means of glancing angle X-ray diffraction (GAXRD) while the Ti depth profiles were obtained from Rutherford backscattering (RBS) analysis. Peak concentrations of the implanted Ti were found to vary with substrate temperature. At the lower end of the range studied, high peak concentrations of Ti were observed and GAXRD analysis indicated the presence of AlTi3. In contrast, substrate temperatures of ~400°C yielded broader implant distributions, extending to greater depths and with lower peak concentrations of implant. These were attributed to temperature induced diffusional effects which favoured the formation of an aluminium rich intermetallic compound Al3Ti.

Evans, P. J.; Knight, S. T.; Samandi, M.

1996-12-01

86

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; B. Mohan; T. R. Parthasarathy

2011-01-01

87

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

88

Cold Spray Deposition of Titanium onto Aluminium Alloys  

Directory of Open Access Journals (Sweden)

Full Text Available 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.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.

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

2010-01-01

89

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

Science.gov (United States)

Phytic acid was used to prepare conversion coating on 2024-T3 aluminium alloy.The corrosion resistance of the conversion coating was studied.The conformation models of phytic acid conversion coating were proposed.

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

2013-09-01

90

A review of friction stir welding of AA 6061 aluminium alloy  

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

91

Comparison between ion implantation and laser alloying of iron for oxidation resistance improvement. Pt. 2. Aluminium alloying  

Energy Technology Data Exchange (ETDEWEB)

Following previous results concerning boron alloying by ion implantation or laser surface melting, the role of aluminium to improve the high temperature oxidation of iron is studied. Laser alloying has a greater efficiency than ion implantation. The aluminium containing phases formed at the metal-scale interface are responsible for the observed protection. The behaviour of the laser surface alloy is quite comparable to that of conventional alloys Fe-5Al. These two techniques, ion implantation and laser irradiation, seem to be of importance for future developments of corrosion protection.

Pons, M.; Caillet, M.; Galerie, A.

1986-11-01

92

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

International Nuclear Information System (INIS)

[en] 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

2004-01-01

93

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

International Nuclear Information System (INIS)

[en] 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

1992-01-01

94

Relationship between hardness and abrasive wear for some aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Abrasive wear of engineering and transport machine components caused by abrasive particles action is a major industrial problem. It is estimated that abrasive wear represents about 50% of the total wear encountered in industrial situations. Therefore it is necessary to develop experimentation to study the wear phenomena in order to optimize and improve the life of machine parts, and therefore save energy and resources. Classically it is considered that abrasive wear is inversely proportional to hardness (Archard law), but in fact several studies showed that the correlation between hardness and abrasive wear coefficient is far from being obvious. A study of an industrial case is proposed to show different morphologies of wear damage. Microscopic observations of aluminium alloy indicate plastic deformation of surface layers, work hardening and recrystallization. When large damage areas are present, subsurface observations show delamination phenomena and grains disorientation. In order to study the correlation between abrasive wear and hardness a modified pin-on-disc tribometer has been developed. This test makes possible to rub an aluminium plate against an abrasive disc in presence of water. The normal load (then the contact pressure) and the sliding speed are controlled. Wear measurements is made by weighing specimens. The effect of abrasive particle size and normal load on two-body abrasive wear have been investigated. A better correlation between abrasive wear and hardness has been found for coarse grains, while for low grain sizes this correlation is not verified. This difference can be explained by the evolution of various wear mechanisms and abrasive grains size. The abrasive wear presents also a linear variation according to the normal load for different size of abrasive grains. Results confirm that hardness is not the unique factor governing abrasive wear resistance. (orig.)

Mezlini, S.; Kapsa, Ph.; Abry, J.C.; Meille, G. [LTDS, UMR CNRS, Ecole Centrale de Lyon, Ecully (France); Ribes, H. [Pechiney Rhenalu Issoire Plant, Z.I. des Listes, Issoire (France); Dif, R. [Pechiney Centre de Recherche de Voreppe, Voreppe (France)

2002-07-01

95

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

International Nuclear Information System (INIS)

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

1993-01-01

96

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

Energy Technology Data Exchange (ETDEWEB)

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

Nakamura, Yasushi; Kobayashi, Yoshio; Kakurai, Yousuke (Nikko Kyodo Co., Ltd., Toda, Saitama (Japan). Central Research lab.)

1993-09-01

97

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)

1966-01-01

98

High temperature yield and tensile strengths of aluminium alloys. [AA 2024, AA 2218, AA 2219  

Energy Technology Data Exchange (ETDEWEB)

Strength values of aluminium alloys at elevated temperature are affected both by the exposure time and temperature. A method to evaluate high temperature yield stresses and tensile strengths taking the exposure time into account is presented in this paper. The method is based on the Larson-Miller time and temperature parameter. Evaluated data are given for commercial AlCu alloys. (orig.).

Sandstroem, R.; Widestig, P. (Royal Inst. of Tech., Stockholm (Sweden). Dept. of Materials Technology)

1992-04-01

99

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

International Nuclear Information System (INIS)

[en] 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)

1992-01-01

100

Analysis of low cycle fatigue in AlMgSi aluminium alloys  

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In this study low-cycle fatigue tests were performed in two AlMgSi aluminium alloys with different chemical composition, namely 6082-T6 and 6060-T6 alloys, using standard round specimens and tube specimens, respectively. The tests were undertaken in strain control with a strain ratio R[var epsilon]=...

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

 
 
 
 
101

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

102

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.).

1989-01-01

103

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

International Nuclear Information System (INIS)

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

2011-01-01

104

High temperature deformation of friction stir processed 7075 aluminium alloy  

International Nuclear Information System (INIS)

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

2005-01-01

105

Performance of aluminium alloys subjected to explosions and/or fire. Final report July 1994  

Energy Technology Data Exchange (ETDEWEB)

This report presents the findings of an extensive review of the performance of aluminium alloys subjected to explosion and fire loading. Particular emphasis is placed on those alloys which are used structurally in offshore applications. An introduction to these alloys is given; it summarises the manufacturing processes, chemical composition, mechanical and physical properties. Product form, availability and handling are also discussed. Requirements of codes of practice and regulatory authorities are highlighted. (author)

NONE

1995-09-01

106

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

Science.gov (United States)

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 ...

G. Gao

1992-01-01

107

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

1993-01-01

108

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

International Nuclear Information System (INIS)

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

2010-06-15

109

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.

2011-01-01

110

Image analysis of atmospheric corrosion of field exposure high strength aluminium alloys  

Science.gov (United States)

The corrosion morphology image acquisition system which can be used in the field was established. In Beijing atmospheric corrosion exposure station, the image acquisition system was used to capture the early stage corrosion morphology of five types of high strength aluminium alloy specimens. After the denoise treatment, wavelet-based image analysis method was applied to decompose the improved images and energies of sub-images were extracted as character information. Based on the variation of image energy values, the corrosion degree of aluminium alloy specimens was qualitatively and quantitatively analyzed. The conclusion was basically identical with the result based on the corrosion weight loss. This method is supposed to be effective to analysis and quantify the corrosion damage from image of field exposure aluminium alloy specimens.

Tao, Lei; Song, Shizhe; Zhang, Xiaoyun; Zhang, Zheng; Lu, Feng

2008-08-01

111

The research of corrosion defects in aluminium alloy SAV-1, irradiated by neutrons  

International Nuclear Information System (INIS)

The study of corrosion resistance of rod from low aluminium alloy SAV-1 after a long term operating in the nuclear reactor WWR-K and in water pool storage are resulted. The corrosion tests executed with usage of chemical and electrochemical methods of an estimation of a fixed potential and corrosion rate in chlorine solution to the environment on an accelerated mode on samples cut from the top and bottom end of a atomic reactor rod. With application of methods of a volume determination by hydrostatic weighting of corrosion of aluminium alloy SAV-1 irradiated by a different fluency of neutrons. Is showing, that the irradiation decrease periods of passivation and accelerates a rate corrosion of aluminium alloy SAV-1. (author)

2003-01-01

112

Stereometry specification and properties of anodization surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

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

J. Konieczny; K. Labisz; J. Wieczorek; L.A. Dobrza?ski

2008-01-01

113

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

Scientific Electronic Library Online (English)

Full Text Available 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 by metal inert gas welding process at varying values of current and voltage after which mechanical tests were performed on the welded samples. The microstructural examination of (more) 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.

Oluwole, Oladele Isiaka; Ajibade, Omotoyinbo Joseph

2010-06-01

114

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

Directory of Open Access Journals (Sweden)

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

Oladele Isiaka Oluwole; Omotoyinbo Joseph Ajibade

2010-01-01

115

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

International Nuclear Information System (INIS)

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

2003-01-01

116

Susceptibility to pitting corrosion of pure aluminium, 2024 alloy and 6056 alloy in chloride-containing sulphate solutions  

Energy Technology Data Exchange (ETDEWEB)

The susceptibility to pitting corrosion of pure aluminium, 2024 T351 alloy and 6056 T6 alloy in 0.1 M Na{sub 2}SO{sub 4} solutions containing chloride ions was investigated. The 2024 alloy seemed to be the least resistant to chloride ion attack. Significant differences appeared between the three materials when the variation of the pit germination rate versus polarization potential was studied. Observations by SEM showed that the susceptibility of the 2024 alloy was related to its copper content. (orig.)

Blanc, C. [Ecole Nat. Superieure de Chimie, 31 - Toulouse (France). Lab. des Materiaux; Lavelle, B. [Ecole Nat. Superieure de Chimie, 31 - Toulouse (France). Lab. des Materiaux; Mankowski, G. [Ecole Nat. Superieure de Chimie, 31 - Toulouse (France). Lab. des Materiaux

1996-12-31

117

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; M. J. Davidson; G. R. N. Tagore

2010-01-01

118

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

Directory of Open Access Journals (Sweden)

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; Z. Derriche; M.Y. Azri

2006-01-01

119

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

120

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

International Nuclear Information System (INIS)

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

1984-01-01

 
 
 
 
121

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

122

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

International Nuclear Information System (INIS)

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

1982-01-01

123

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

Energy Technology Data Exchange (ETDEWEB)

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

Drobyazin, V.N.; Podzirej, Yu.S.; Polovneva, S.P.; Soldatenko, G.A.; Popovich, K.D. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

1982-12-01

124

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.

1000-01-00

125

Spectrochemical determination of impurities in aluminium alloys by DC arc technique  

International Nuclear Information System (INIS)

[en] Two spectrochemical methods are described for the determination of 12 impurities in aluminium alloys. These methods are suitable for the determination of traces of the following elements in the range of 5-400 ppm: B, Cd, Cr, Cu, Mg, Mn, Ni, Pb, Sb, Sn, Ti, Zn. (author)

1983-01-01

126

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of process parameters on metallurgical properties of friction stir welded aluminium alloy 6063-O was analysed in the present study. Samples were friction stir welded under tool rotational speed of 600, 800 and 1200 rpm and traversing speed of 0.6, 0.9 and 1.2 mm sec-1, with an ...

A. Varun Kumar; K. Balachandar

127

Study of hydrogen embrittlement in aluminium alloy 2024 in the longitudinal direction  

Energy Technology Data Exchange (ETDEWEB)

A comparative study of the hydrogen effect on overall ductility in the rolling direction of aluminium alloy 2024 in the T351 temper condition and aluminium alloy 2024 aged at 190degC for 7 h has been conducted. Hydrogen-pre-charged and hydrogen-free sheet tensile specimens have been tested at either a constant or an alternating strain rate. It has been found that internal hydrogen caused severe degradation in overall plastic elongation of aluminium alloy 2024-T351 and that in artificially aged alloy 2024 the embrittlement was observed only after the onset of necking. It has been observed that hydrogen-induced modification of the strain rate dependence of flow stress by reducing dynamic hardening in alloy 2024-T351 aged at 190degC for 7 h and enhancing dynamic softening in alloy 2024-T351. It is suggested that hydrogen embrittlement is caused by hydrogen-induced enhancement of plastic deformation localization that mainly affects non-uniform plastic deformation. (orig.).

Zeides, F.; Roman, I. (Graduate School of Applied Science and Tech., Hebrew Univ. of Jerusalem (Israel))

1990-05-01

128

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.

2012-07-30

129

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; Dilermando Nagle Travessa; Asunción García Escorial; Marcela Lieblich

2007-01-01

130

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

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

131

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

132

Effect of aluminium on TRIP Fe-Mn-Al alloy steels at room temperature  

Energy Technology Data Exchange (ETDEWEB)

Fe-Mn-Al alloy steel has undergone many significant developments during the past few years, and it is considered to be a steel of high strength and toughness. Studies and test results have shown that Fe-Mn-Al is a good potential replacement for conventional stainless steels which contain nickel and chromium additions. Recently, it has been found that strain-induced martensitic transformation at room temperature is possible in austenitic Fe-Mn-Al alloy. Further study has shown that the [alpha]' martensite can improve the mechanical properties of these Fe-Mn-Al alloys. However, as the aluminium content increases, the strain-induced phase transformation is inhibited. Moreover, the mechanical properties of these materials are very dependent on the aluminium content. (orig.).

Chen, F.C.; Chou, C.P. (Dept. of Mechanical Engineering, National Chiao-Tung Univ., Hsinchu (Taiwan)); Li, P.; Chu, S.L. (Div. of Materials Reliability, Materials Research Labs., Industrial Tech. Research Inst., Hsinchu (Taiwan))

1993-02-28

133

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.; Smolej A.; Doberšek M.

2009-01-01

134

Modelling of friction for high temperature extrusion of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years, finite-element (FE) simulations have been extensively used in scientific research and industrial practice to analyse the extrusion process. A basic issue of FE simulations is the accuracy of the results, which is mainly determined by the viscoplastic material behaviour of aluminium ...

Wang, L.

135

Cavitation-aided grain refinement in aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditi...

Atamanenko, T.V.

136

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

Energy Technology Data Exchange (ETDEWEB)

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.

Singh, M. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)]. E-mail: mulayam_singh@hotmail.com; Mondal, D.P. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India); Das, S. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)

2006-03-15

137

Study od early stages of structure formation in irradiated aluminium alloys  

International Nuclear Information System (INIS)

[en] 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

1980-06-18

138

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.

2006-02-22

139

Mechanism of seizure of aluminium-silicon alloys dry sliding against steel  

Energy Technology Data Exchange (ETDEWEB)

A steel ball was slid on aluminium-silicon alloys at different temperatures. After the coefficient of friction had been measured, the surface shear stress was deconvoluted using a two-term model of friction. The ratio of surface shear stress to bulk hardness was calculated as a function of temperature, silicon content and alloying additions. These results are qualitatively similar to those recorded for pre-seizure specimens slid against an En24 disc in a pin-on-disc machine. This similarity, when viewed in the context of the phenomenon of bulk shear, provides a model for seizure of these alloys. (orig.)

Somi Reddy, A. [Dept. of Mechanical Engineering, Indian Inst. of Science, Bangalore (India); Pramila Bai, B.N. [Dept. of Mechanical Engineering, Indian Inst. of Science, Bangalore (India); Murthy, K.S.S. [Dept. of Mechanical Engineering, Indian Inst. of Science, Bangalore (India); Biswas, S.K. [Dept. of Mechanical Engineering, Indian Inst. of Science, Bangalore (India)

1995-03-01

140

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.

Sergey A. Pyachin; Sergey V. Nikolenko; Alexander A. Burkov; Nikolay A. Suy

2013-01-01

 
 
 
 
141

Recycling of Li-containing aluminium alloys; Recycling Li-haltiger Aluminiumlegierungen  

Energy Technology Data Exchange (ETDEWEB)

The lithium contained in Al-Li-scraps represents a value, which lies clearly over that of aluminium. In addition, the enormous manufacturing and processing costs of Al-Li alloys further limit their application range. To ensure a broader application of this group of alloys, a complete recycling concept for the resulting residual substances must be developed, so that a 100% recyclability is guaranteed. By thermodynamic calculations as well as experimental investigations it was proven that the complete recovery of the initial Al-Li alloys is possible with the aid of melting under high purity LiCl. (orig.)

Arnold, A.; Sauermann, R.; Friedrich, B. [RWTH Aachen (Germany). IME Metallurgische Prozesstechnik und Metallrecycling

2006-09-15

142

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; A.S.M. Hamouda

2010-01-01

143

Effect of composition on the superplasticity of aluminium scandium alloys  

International Nuclear Information System (INIS)

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

1992-01-01

144

Phase composition and properties of rapidly cooled aluminium-zirconium-chromium alloys  

International Nuclear Information System (INIS)

Using the methods of physicochemical analysis the interaction of aluminium with zirconium and chromium is studied. Polythermal cross sections between Al3-Zr-Al7Cr and radial polythermal cross section from aluminium-rich corner with the ratio of components Zr:Cr=5:7 by mass are constructed. The effect of zirconium and chromium content on electrochemical characteristics of aluminium-base rapidly quenching alloys in systems Al-Cr, Al-Zr, Al-Cr-Zr. An increase in chromium concentration in oversaturated solid solution of Al-Cr system expands considerably the range of passive state. When Al7Cr phase appears the range of passive stae vanishes.

1989-01-01

145

Modelling research of hydrogen desorption from liquid aluminium and its alloys  

Directory of Open Access Journals (Sweden)

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

M. Saternus

2011-01-01

146

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

Energy Technology Data Exchange (ETDEWEB)

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

Elangovan, K. [Department of Production Engineering, Sathyabama University, Chennai, Tamil Nadu (India)], E-mail: elamko@rediffmail.com; Balasubramanian, V. [Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India)], E-mail: visvabalu@yahoo.com; Babu, S. [Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India)], E-mail: ssbaaboo77@yahoo.com

2009-01-15

147

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

International Nuclear Information System (INIS)

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

2009-01-01

148

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)

2007-01-01

149

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

International Nuclear Information System (INIS)

[en] 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.

2009-08-30

150

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-30

151

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

Science.gov (United States)

Restoration of obliterated engraved marks on high strength Al-Zn-Mg-Cu alloy (AA7010) surfaces by etching technique was studied. The alloy surfaces were mechanically engraved with some identification marks using "Gravograph". The marks were then erased by removing the metal to different levels up to and below the depth of engraving. Five metallographic reagents were tested on the obliterated surfaces by etching. The following two methods (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH were found to be quite effective to reveal the obliterated marks. These two procedures were also able to show effectively the marks obliterated by over-engraving and centre punching. Of the two techniques immersion in phosphoric acid provided more contrast. Interestingly, alternate swabbing of 60% HCl and 40% NaOH presented itself to be the common reagent for restoration on pure aluminium as well as its alloy surfaces. This is evident from our own current experiments and those of earlier researchers [G. Peeler, S. Gutowski, H. Wrobel, G. Dower, The restoration of impressed characters on aluminium alloy motor cycle frames, J. Forensic Ident. 58 (1) (2008) 27-32; M. Izhar M. Baharum, R. Kuppuswamy, A.A. Rahman, Restoration of engraved marks on aluminium surfaces by etching technique, Forensic Sci. Int. 177 (2008) 221-227]. The findings have assumed importance as engines and chassis of cars and frames of firearms are currently made of high strength aluminium alloys and recovery on these surfaces by current methods is not satisfactory. PMID:20022189

Bong, Yeu Uei; Kuppuswamy, R

2010-02-25

152

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

UK PubMed Central (United Kingdom)

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

Bong YU; Kuppuswamy R

2010-02-01

153

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 ...

Chaussumier, Michel; Mabru, Catherine; Shahzad, Majid; Chieragatti, Rémy; Rezaï-Aria, Farhad

154

Determination of initial stages of recrystallization in aluminium alloys by X-ray diffraction  

International Nuclear Information System (INIS)

Aluminium is a metal with a wide variety of application, such as beer cans, pans, door and window borders, and others more advanced, such as airplane structure, car engines, nuclear reactors components, rocket propulsion components and so on. Most of aluminium application is in alloy form. Such alloys must present suitable mechanical and chemical properties that are obtained, not entirely, by microstructure development. In this work, the beginning of recrystallization processes of AA1050 and AA3003 aluminium alloys were studied using X-ray diffraction techniques, transmission electron microscopy and hardness test. For such a sample, an initial heat treatment was done in order to homogenize the samples microstructure, followed by cold rolling and submitted again to a heat treatment in different temperatures in a hot furnace. After that samples were analyzed to verify the beginning of the recrystallization. Vickers hardness test revealed that the beginning of recrystallization is between 150 and 300 deg C for 1050 aluminium alloy and 200 and 300 deg C for 3003 aluminium alloy. X-ray diffraction using transmission chamber showed that the beginning of recrystallization is 240 and 260 deg C for AA1050 and AA3003, respectively. These temperatures were determined as the diffraction patterns recorded in the photographic plates changes when the recrystallization takes place. In this way, the deformed sample shows continuous concentric lines and the beginning of recrystallization is characterized by the occurrence of defined spots in this pattern. The Pole Figures goniometric method revealed that the beginning of recrystallization takes place between 250 and 300 deg C for both alloys. In the same way, orientation distribution functions showed the same temperature range for the recrystallization. However, the analysis by ? and ? fiber figures, the recrystallization temperatures are 240 and 260 deg C for AA1050 and AA3003, respectively. Finally, after the analysis of all results we concluded that the beginning of recrystallization is between 200 and 300 deg C for both alloys, more specifically 240 and 260 deg C for AA1050 and AA3003, respectively. (author)

2000-01-01

155

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

156

Powder-metallurgical production of aluminium alloys with high strength at elevated temperatures  

Energy Technology Data Exchange (ETDEWEB)

Pure aluminium powder (Al 99.7) was reactively milled in an Attritor with 1 to 3 mass-% of carbon (soot) under a controlled atmosphere, to form a granulate. The product was pre-compacted into PM extrusion billets in 4 different ways: (1) ESC (evacuated sealed can): compressed under vacuum in a sleeve, (2) HIP (hot isostatic pressing): compacted by hot isostatic pressing in the container, (3) VHP (vacuum hot pressing): compacted by hot isostatic pressing in the container under vacuum, or (4) CIP (cold isostatic pressing): compacted by cold isostatic pressing with no sleeve. The billets were then consolidated to semifabricate sections by direct hot extrusion at approximately 500/sup 0/C. During the reactive milling and subsequent billet preheating, approximately 1 mass-% of the carbon was transformed to give 4.5 vol.-% of aluminium carbide (Al/sub 3/C/sub 4/), and 1 mass-% of aluminium hydroxide to 1.6 vol.-% of aluminium oxide (Al/sub 2/O/sub 3/). Acting as finely distributed dispersoids, these conferred a higher hardness and great thermal stability of the structure. Correspondingly, the high strength and excellent creep behaviour of these materials at elevated temperatures render them suitable for use particularly in the range 300 to 500/sup 0/C, within which the known favourable properties of aluminium are fully retained. Such alloys are therefore a noteworthy alternative to titanium and ceramics.

Brockmann, G.J.; Baumgarten, J.

1989-04-01

157

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

International Nuclear Information System (INIS)

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

2010-07-01

158

Stress corrosion cracking behaviour of laser treated aluminium alloy 7075 using a slow strain rate test  

Energy Technology Data Exchange (ETDEWEB)

The effect of excimer laser surface treatment on the stress corrosion cracking (SCC) behaviour of 7075 aluminium alloy was studied in a 3.5%NaCl solution using a slow strain rate test (SSRT). The test was conducted at the open circuit potential, a constant anodic or cathodic potential. The results of the SSRT and examination of the fracture surface of the specimens showed that the laser treatment can significantly increase the SCC initiation resistance of 7075 aluminium alloy, and reduce the degree of intergranular attack. This was due to the absence of coarse constituent particles and precipitate free grain boundaries in the laser melted layer. Moreover, the thin compact Al{sub 2}O{sub 3} layer with nanocrystalline structures formed at the top surface of the laser melted layer serves as a barrier to retard corrosion attack. (author)

Yue, T.M.; Yan, L.J.; Dong, C.F.; Chan, C.P.

2005-08-15

159

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.

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

2010-01-01

160

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

International Nuclear Information System (INIS)

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

1986-01-01

 
 
 
 
161

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

Scientific Electronic Library Online (English)

Full Text Available 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 Fre (more) undlich 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.

Nkiko, Mojisola O.; Bamgbose, Janet T.

2011-11-01

162

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; Janet T. Bamgbose

2011-01-01

163

Erosion of molybdenum alloy with aluminium nitride additions  

International Nuclear Information System (INIS)

[en] A study is made of the erosion resistance of the Mo-AlN alloys depending on the content of AlN dispersion particles. The measurements of the erosion resistance, hardness, grain size, tensile strength, relative elongation have been made on samples of molybdenum alloys with additions of AlN dispersion particles of 0.5 to 1 mc size in the amount of 0.5; 1; 4 and 8 vol%. The temperature dependence is determined of the electric conductivity for both molybdenum and molybdenum alloy containing 4 vol.% AlN. The studies have shown that no direct relationship exists between the hardness, grain size of the Mo-AlN alloys and their erosion resistance. The erosion dependence on the dispersion particle content for the Mo-AlN alloys is described by a curve with the minimum. The alloy containing 2 vol.% AlN, having the highest plasticity, proves to be the most erosion resistant one. It has been found that the electric conductivity changes in the alloys produce no considerable effect on the extent of their erosion

1975-01-01

164

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; S. Malara; T. Ta?ski

2009-01-01

165

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

International Nuclear Information System (INIS)

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

2009-01-15

166

Microhardness and parameters of fine structure of quenched aluminium alloy implanted with xenon ions  

International Nuclear Information System (INIS)

[en] The phase-structure state of quenched aluminium alloy D16 implanted with xenon ions was studied. Ion energy and dose range were 167 MeV and 5·1012 - 1014 cm-2. X-ray and microhardness techniques were used. It was showed that during implantation radiation-induced decomposition of supersaturated solid solution with precipitation of the hardening phases. (authors)

2009-01-01

167

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

International Nuclear Information System (INIS)

[en] 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

1988-01-01

168

Laser surface treatments for adhesion improvement of aluminium alloys structural joints  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-08-15

169

Laser surface treatments for adhesion improvement of aluminium alloys structural joints  

International Nuclear Information System (INIS)

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

2007-01-01

170

Radiative heredity in iron and aluminium alloys. [Neutrons  

Energy Technology Data Exchange (ETDEWEB)

Methods of roentgenostructural analysis and Moessbauer spectroscopy have been used to study the effect of radiation heredity in the ordering alloy Fe/sub 3/Al. It is found that thermally stable submicroregions enriched with Fe atoms appear in the alloy preliminarily irradiated by a fluence of 1x10/sup 23/ nxm/sup -2/ neutr. (E > 0.1 MeV) unlike a non-irradiated alloy due to heating up to the temperature of 0.85 Tsub(melt.) and quenching.

Ibragimov, Sh.Sh.; Skakov, M.K.; Melikhov, V.D.; Zhetbaev, A.K.; Vereshchak, M.F.; Zhantikin, T.M. (AN Kazakhskoj SSR, Alma-Ata. Inst. Yadernoj Fiziki)

1982-07-01

171

Zinc-Aluminium Casting Alloys Containing 8-30% Al.  

Science.gov (United States)

The work concentrates to study the solidification sequence of Zn-Al alloys having various compositions. The effects of the basic composition, cooling rate and melt treatment on as cast microstructure is studied. In addition the connection between the comp...

T. Rantala V. Rauta

1985-01-01

172

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.).

1991-01-01

173

Tribological Properties of Aluminium 2024 Alloy Beryl Particulate MMC's  

Directory of Open Access Journals (Sweden)

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

H.B. Bhaskar

2012-01-01

174

Advances in aluminium alloy products for structural applications in transportation  

International Nuclear Information System (INIS)

[en] 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.)

1993-01-01

175

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

International Nuclear Information System (INIS)

[en] 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)

1991-01-01

176

Influence of time on residual stresses in friction stir welds in agehardenable 7xxx aluminium alloys  

International Nuclear Information System (INIS)

[en] Friction stir welding (FSW) can be used to weld 7xxx series wrought aluminium alloys. As these materials are age-hardenable, their properties can change with time. This work used the neutron diffraction technique to measure the residual stresses around a FSW in a 7xxx alloy and to determine how these residual stresses changed with time. It was found that the residual stresses associated with the weld nugget decreased, while those associated with the heat-affected zone increased with time. This is in contrast to strength and hardness values that increased in all regions of the weld with time

2008-01-01

177

Influence of time on residual stresses in friction stir welds in agehardenable 7xxx aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Friction stir welding (FSW) can be used to weld 7xxx series wrought aluminium alloys. As these materials are age-hardenable, their properties can change with time. This work used the neutron diffraction technique to measure the residual stresses around a FSW in a 7xxx alloy and to determine how these residual stresses changed with time. It was found that the residual stresses associated with the weld nugget decreased, while those associated with the heat-affected zone increased with time. This is in contrast to strength and hardness values that increased in all regions of the weld with time.

Linton, V.M. [University of Adelaide, Adelaide, South Australia (Australia)], E-mail: valerie.linton@adelaide.edu.au; Ripley, M.I. [ANSTO, Lucas Heights, New South Wales (Australia)

2008-10-15

178

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

Energy Technology Data Exchange (ETDEWEB)

The crystallisation kinetics of liquid aluminium-titanium alloys with microscopic TiB{sub 2} 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 TiB{sub 2} particles during solidification. Prior to the main transformation, weak reflections of a metastable TiAl{sub 3} phase were detected. This observation finally pinpoints the highly debated mechanism responsible for enhanced grain nucleation in Al-Ti-B alloys.

Iqbal, N. [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Dijk, N.H. van [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)]. E-mail: nvdijk@iri.tudelft.nl; Offerman, S.E. [Department of Materials Science and Engineering, Delft University of Technology, Rotterdamseweg 137, 2628 AL Delft (Netherlands); Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Moret, M.P. [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9 (France); Katgerman, L. [Department of Materials Science and Engineering, Delft University of Technology, Rotterdamseweg 137, 2628 AL Delft (Netherlands); Kearley, G.J. [Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

2005-06-15

179

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

Directory of Open Access Journals (Sweden)

Full Text Available Cerium conversion layers (CeCL) have been investigated as a replacement for chromium conversion layers to protect Al alloys against corrosion. In this work the microstructure and the electrochemical behaviour of aluminium alloy 2024 with and without CeCL were investigated using, respectively, SEM-EDX and EIS. EDX results have shown that the presence of dispersed plated Cu particles on the alloy surface enhances the formation of the CeCL increasing the intensity of Ce peaks in the EDX spectra. EIS measurements on conversion-coated samples have shown that the presence of the layer increases the impedance, and that its presence is detected by the presence of a high frequency time constant. Results of potentiodynamic experiments have shown that the corrosion protection afforded by the conversion layer is due to the hindrance of the oxygen reduction reaction and that the pitting potential of the alloy is not changed.

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

2003-01-01

180

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)

1979-01-01

 
 
 
 
181

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.

182

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

International Nuclear Information System (INIS)

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

1966-01-01

183

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

184

Phase-oriented surface segregation in an aluminium casting alloy  

International Nuclear Information System (INIS)

[en] 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.

2009-02-15

185

Electrochemical oxidation of aluminium-cerium alloys in acid solutions  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work was to study the influence of cerium (4, 10 and 20 mass %) in aluminum-cerium alloys on the properties of the anodic film and on the electrochemical kinetics of anodic dissolution. It has been shown that regulation of the thickness and porosity of anodic aluminum oxide by addition of cerium is possible in principle. Introduction of cerium (up to 10 mass %) into aluminum raises the rate of anodic oxidation is sulfuric acid solution in comparison with pure aluminum. Highly porous films may be obtained by anodizing aluminum-cerium alloy containing more than 10 mass % of cerium in sulfuric-acid, while for formation of films of low porosity aluminum alloyed with cerium should be anodized in oxalic acid electrolytes.

Bundzhe, V.G.; Morozova, O.I.; Zabotin, P.I.

1986-02-10

186

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

187

Aluminium casting alloy for high strength/high temperature applications  

Energy Technology Data Exchange (ETDEWEB)

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

Yen, C.M.; Evans, W.J.

1992-06-09

188

Aluminium casting alloy for high strength/high temperature applications  

International Nuclear Information System (INIS)

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

1990-11-08

189

Pitting by corrosion in aluminium and Al-6201 alloy  

International Nuclear Information System (INIS)

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

1998-01-01

190

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

Directory of Open Access Journals (Sweden)

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

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

2007-01-01

191

Stereometry specification of anodisation surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

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

J. Konieczny; K. Labisz; J. Wieczorek; L. A. Dobrza?ski

2008-01-01

192

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

Energy Technology Data Exchange (ETDEWEB)

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.

Chambers, B.D. [University of Virginia, Charlottesville, VA (United States)]. E-mail: bdc5x@virginia.edu; Taylor, S.R. [University of Mississippi Medical Center, Department of Biomedical Materials Science, 2500 North State Street, Jackson, MS 39216 (United States)]. E-mail: srtaylor@umsmed.edu

2007-03-15

193

Effect of Refiner Addition Level on Zirconium-Containing Aluminium Alloys  

International Nuclear Information System (INIS)

It is well known that in aluminium alloys containing Zr, grain refiner additions do not function as desired, producing an effect often referred to as nuclei poisoning. This paper investigates the structure of direct chill-cast ingots of commercial AA3003 aluminium alloys, with and without Zr, at various addition levels of Al5Ti1B master alloy. In Bridgman experiments simulating ingot solidification, Zr-containing alloys were studied after the addition of various amounts of Ti. It could be demonstrated, in both ingot casting and simulation experiments, that Zr poisoning can be compensated for by adding more Ti and/or Al5Ti1B. The results confirm better refinement behaviour with the addition of Ti + B than of only Ti. The various combinations of Zr and Ti also influenced the formation of AlFeMn phases, and the precipitation of large Al6(Mn,Fe) particles was revealed. AlZrTiSi intermetallic compounds were also detected.

2012-01-12

194

Microstructural and mechanical evolutions within friction stir welds of precipitation hardened aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Two precipitation hardened aluminium alloys developed for aerospace applications have been studied after friction stir welding: 6056-T78 and 7349-T6. General properties of friction stir welds made of precipitation hardened aluminium alloys are highlighted and discussed. The heat affected zone (HAZ) is characterised by a coarsening/transformation of initial hardening precipitates. The dissolution is favoured in the thermomechanically affected zone (TMAZ) and the central weld nugget, the latter being characterised by a full dissolution of initial hardening precipitates. The cooling part of the thermal cycles encountered during welding can favour locally the heterogeneous precipitation : on dispersoids in the TMAZ of the 6056-T78 alloy and at grain boundaries in the weld nugget of the 7349-T6 alloy. In both cases, the minimum of hardness corresponds to a coarse and extensive precipitation. The tensile behaviour of the weld is strongly influenced by those microstructural variations : yielding will occur first in the weak zone, then in the TMAZ and the weld nugget. The partitioning of the plastic deformation between those zones leads to a satisfactory elongation to rupture of the whole weld. (orig.)

Denquin, A.; Lapasset, G. [ONERA, Chatillon (France); Allehaux, D.; Campagnac, M.H. [EADS-CCR, Suresnes (France)

2003-07-01

195

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; R. Nakamura; S. Kuma; H. Watari

2013-01-01

196

Effect of fly ash particles on the mechanical properties of aluminium casting alloy A535  

Energy Technology Data Exchange (ETDEWEB)

The addition of fly ash into aluminium alloys has the potential to reduce the cost and density of aluminium castings while improving other physical and mechanical properties of the resulting metal matrix composites (MMCs). In the present study, the effect of fly ash addition on the mechanical properties of aluminium casting alloy 535 (A535) was investigated by means of hardness measurements, tensile testing, Charpy impact testing, optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray fluorescence spectroscopy (XFS). The unreinforced A535 and its MMCs containing a mixture of 5 wt-% fly ash and 5 wt-% silicon carbide, 10 wt-% fly ash and 15 wt-% fly ash were investigated in the as cast and heat treated conditions. The results show that increasing the fly ash content of the melt increased the porosity of the castings, which ultimately affected the tensile and impact properties of the MMCs. The microhardness, tensile strength and Charpy impact energy of the composites decreased with increasing fly ash content. The loss in mechanical properties and impact resistance of the MMCs is attributed partly to the depletion of solid solution strengthening magnesium atoms from the matrix and partly to porosity.

Gikunoo, E.; Omotoso, O.; Oguocha, I.N.A. [University of Saskatchewan, Saskatoon, SK (Canada). Dept. of Mechanical Engineering

2005-02-01

197

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

Directory of Open Access Journals (Sweden)

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

W.K. Krajewski; P.L. Zak; J. Orava; A.L. Greer; P.K. Krajewski

2012-01-01

198

Dilatometer study of rapidly solidified aluminium-silicon based alloys  

International Nuclear Information System (INIS)

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

2009-01-01

199

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)

2011-01-01

200

Dilatometer study of rapidly solidified aluminium-silicon based alloys  

Energy Technology Data Exchange (ETDEWEB)

Aluminum-Silicon alloys are sought in a large number of automotive and aerospace applications due to their low coefficient of thermal expansion and high wear resistance. The present study focused on structural transformations as a function of the temperature of rapidly solidified hypereutectic Al{sub 100-x}Si{sub x} (x = 12, 22 and 40) alloys. Different structures out of equilibrium have been obtained after casting in sand, graphite and copper moulds and by melt spinning. The retained Si content in supersaturated alpha Al and the precipitation of Si is discussed in the light of the dilatometer studies [1, 2, 3] complemented by metallographic microscopy, XRD and DSC [4] measurements. A Kissinger analysis was used to determine the activation energy for the precipitation of supersaturated Si content.

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

2009-01-01

 
 
 
 
201

WEAR STUDIES OF ALUMINIUM ZINC ALLOY METAL MATRIX COMPOSITES  

Directory of Open Access Journals (Sweden)

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

H.P.Varade; Dr.A.G.Thakur; P.M.Patare; N.D.Sadaphal

2013-01-01

202

Wear behaviour of AA6061 aluminium alloy and its composites  

Energy Technology Data Exchange (ETDEWEB)

This study investigates the wear resistance of four AA6061 MMCs together with the monolithic AA6061 alloy, all in the T6 condition, using a pion-on-disc test. In addition to the widely studied 20 vol.% Saffil MMCs, the present investigation considered a hybrid of 11% Saffil +20% SiC{sub p} and a high volume fraction SiC{sub p} MMC, AA6061+60% SiC{sub p}. The wear behaviour against P400 SiC grit adhesive bonded paper and against BS817M40(EN24) steel were explored under an applied load of 9.8 N with a nominal contact pressure of 0.5 MPa. It was found that after testing against SiC grit, AA6061+Saffil showed little advantage over the monolithic alloy, but the other three composites had a significant improvement in wear resistance. The hybrid and the AA6061+60% SiC showed the best performance. Only small improvements were noted for AA6061+Saffil and AA6061+20% SiC over the monolithic alloy, when tested against steel. However, the addition of 11% Saffil to 20% SiC in the hybrid, resulted in this composite and the AA6061+60% SiC being retained in regime I of the Alpas and Zhang classification, and recording low wear rates. (orig.)

Gurcan, A.B. [Dept. of Metallurgy and Engineering Materials, Univ. of Strathclyde, Glasgow (United Kingdom); Baker, T.N. [Dept. of Metallurgy and Engineering Materials, Univ. of Strathclyde, Glasgow (United Kingdom)

1995-09-01

203

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.

2008-01-01

204

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-01-01

205

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

International Nuclear Information System (INIS)

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

2007-04-07

206

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; T. Haga; H. Watari; S Kumai

2007-01-01

207

Continuous roll casting of aluminium alloys – casting parameters analysis  

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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; I. Duplan?i?; B. Lela

2010-01-01

208

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; A. Zghal; E. Bayraktar

2007-01-01

209

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

Energy Technology Data Exchange (ETDEWEB)

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

Ravisankar, V. [Department of Manufacturing Engineering, Annamalai University, Annamalainagar 608 002, Tamil Nadu (India); Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalainagar 608 002, Tamil Nadu (India)]. E-mail: visvabalu@yahoo.com; Muralidharan, C. [Department of Manufacturing Engineering, Annamalai University, Annamalainagar 608 002, Tamil Nadu (India)

2006-07-01

210

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

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

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

2008-01-01

211

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

Scientific Electronic Library Online (English)

Full Text Available 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 of a FeCr and a FeCrY alloy coated with an aluminium based paint has been studied. The objective was to form the more resistant alumina surface layer on an aluminium free alloy. (more) 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.

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

2008-09-01

212

Ductile fracture locus of AC4CH-T6 cast aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Cast aluminium alloys have found wide application to manufacture lighted-weight components of complex shape in automotive and aerospace industries. To improve the strength and ductility of cast aluminium alloys, it is necessary to study their fracture properties by conducting a series of tests. This study addresses calibration of ductile fracture property of the cast aluminium alloy (AC4CH-T6) made by the gravity die casting with sand mold.Design/methodology/approach: 6 round bar specimens and 6 butterfly specimens are machined from the actual cast component. The tensile tests on the smooth and notched round bar specimens are performed to calibrate the fracture strain in the range of high positive stress triaxialities. The combined loading tests on the butterfly specimens are carried out using a uniquely designed Universal Biaxial Testing Device (UBTD). These tests cover the fracture properties in the rage of low and negative stress triaxialities. Detailed finite element models of all the tests are developed. The fracture locus in the space of the effective plastic strain to fracture and the stress triaxiality are constructed in a wide rage from -1/3 to 1.0.Findings: It is found that material ductility sharply decreases with the stress triaxiality. The material ductility at the negative stress triaxiality is much higher than that in the positive stress triaxiality.Research limitations/implications: Large spread of data is observed for those tests repeated on the same loading configuration, necessitating the statistical analysis of the fracture processes.Practical implications: It is expected that such a fracture criterion would be able to correctly predict the fracture response of actual cast aluminum components under complex loading in the practical applications.Originality/value: The conventional researches focused on the material ductility at the stress triaxiality larger than +1/3. The present study showed the material ductility at the wide range of stress triaxiality from -1/3 to 1.0.

H. Mae; X. Teng; Y. Bai; T. Wierzbicki

2009-01-01

213

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

International Nuclear Information System (INIS)

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

2009-07-01

214

Corrosion Characteristics and Kinetics of Zircaloys and Aluminium Alloys  

International Nuclear Information System (INIS)

[en] 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

1998-01-01

215

The microstructure of mechanically alloyed nanocrystalline aluminium-magnesium  

Energy Technology Data Exchange (ETDEWEB)

The effect of the nominal Mg content and the milling time on the microstructure of mechanically alloyed Al(Mg) solid solutions is studied. The crystallite size distribution and the dislocation structure are determined by X-ray diffraction peak profile analysis. Magnesium gradually goes into solid solution during ball milling and after 3 h almost all of the Mg atoms are soluted into the Al matrix. With increasing milling time the Mg content in solid solution, the dislocation density as well as the hardness are increasing, whereas the crystallite size is decreasing. A similar tendency of these parameters is observed at a particular duration of ball milling with increasing of the nominal Mg content. At the same time for a long milling period the dislocation density slightly decreases together with a slight reduction of the hardness. (orig.)

Gubicza, J. [Dept. of General Physics, Eoetvoes Univ., Budapest (Hungary); Dept. of Solid State Physics, Eoetvoes Univ., Budapest (Hungary); Kassem, M. [Dept. of Materials Science and Engineering, Faculty of Petroleum and Mining, Suez Canal Univ., Suez (Egypt); Ungar, T. [Dept. of General Physics, Eoetvoes Univ., Budapest (Hungary)

2004-07-01

216

Ultrasonic speed in liquid binary aluminium base alloys  

International Nuclear Information System (INIS)

[en] Experimental results are presented of study of the ultrasound velocity in liquid alloys Al-Sb, Al-Te, Al-Cu, Al-Mn, Al-Bi of various concentrations from the liquidus temperature up to 1200-1300 deg C. In the Al-Te system the velocity increases in the interval 0-10 mass% Te and decreases within 10-30% with Te concentration. It is assumed that in the concentration interval 0-10 mass% Te the ultrasound velocity increases as a result of the formation of a binary system Al-Al5 Te. The higher concentration of the second component leads to a higher sound velocity. The higher concentrations result in Al-Al5Te-Te system formation. The higher content of the third component causes a lower velocity. Experimental data are compared with calculations performed on the basis of an ion-plasma model simulating the structure of liquid metals

1977-01-01

217

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

2002-01-01

218

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

International Nuclear Information System (INIS)

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

1993-01-01

219

Deformation-induced small-angle scattering contrast in aluminium alloys  

International Nuclear Information System (INIS)

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

2005-01-01

220

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

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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; S. SULAIMAN; M.K.A. ARIFFIN; B.T.H.T BAHARUDDIN; A.A. FAIEZA

2012-01-01

 
 
 
 
221

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

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

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

2008-01-01

222

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

International Nuclear Information System (INIS)

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

1992-06-16

223

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

International Nuclear Information System (INIS)

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

2007-01-01

224

New technique of corrosion protection of aluminium alloys in high-temperature water of nuclear power plants  

International Nuclear Information System (INIS)

[en] The study results on principally new class of high-temperature universal inhibitors - iso- and heteropolycompounds of tungsten are presented. The method for corrosion protection of aluminium alloys in high-temperature water is proposed. It is based on preliminary thermochemical processing of the alloy surface in solutions of the above-mentioned compounds. Similar to implantation a thin tungsten-containing layer with special structure and high protective properties is created on the metal surface, which makes it possible to decrease the corrosion-velocity rate of aluminium compounds in hot water at 250-300 Deg C up to the level of zirconium ones

1997-01-01

225

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

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

S. Mitrovi?; M. Babi?; B. Stojanovi?; N. Miloradovi?; M. Panti?; D. Džuni?

2012-01-01

226

The role of strontium in modifying aluminium–silicon alloys  

International Nuclear Information System (INIS)

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

2012-01-01

227

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.

2007-12-15

228

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

International Nuclear Information System (INIS)

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

2011-01-10

229

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-06-15

230

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.

2005-01-01

231

Triazole and thiazole derivatives as corrosion inhibitors for AA2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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.

Zheludkevich, M.L. [Department of Ceramics and Glass Engineering, University of Aveiro, 3810-193 Aveiro (Portugal)]. E-mail: mzheludkevich@cv.ua.pt; Yasakau, K.A. [Department of Ceramics and Glass Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Poznyak, S.K. [Department of Ceramics and Glass Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Institute for Physico-Chemical Problems, Belarusian State University, 220050 Minsk (Belarus); Ferreira, M.G.S. [Department of Ceramics and Glass Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Instituto Superior Tecnico, ICEMS, Dep. Chem. Eng., Av. Rovisco Pais 1049-001 Lisbon (Portugal)

2005-12-15

232

An in-situ study of substructural evolution in a single-phase aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

In-situ hot deformation has been carried out in a field emission gun SEM equipped with an EBSD system to study dynamic subgrain growth and substructural evolution in a single-phase aluminium alloy. {l_brace}110{r_brace} left angle 001 right angle oriented single crystals of the alloy were deformed in a channel-die in plane strain compression at 300 C at a strain rate of 10{sup -1}s{sup -1} before in-situ straining in tension at strain rates of 10{sup -4} to 10{sup -3}s{sup -1} and at temperatures from 300 to 350 C. Significant dynamic subgrain growth was found to occur during a transient period during which the compressed microstructure evolved towards a steady state corresponding to the strain rate applied. The mechanisms of dynamic recovery are seen to involve both sub-boundary migration and subgrain dissolution and formation. (orig.)

Huang, Y.; Humphreys, F.J. [Manchester Materials Science Centre, Univ. of Manchester and UMIST, Manchester (United Kingdom)

2002-07-01

233

Determination of microgram quantities of silver in aluminium-, iron-, and nickel-base alloys.  

UK PubMed Central (United Kingdom)

Trace quantities of silver in commercial nickel and its alloys are quantitatively extracted from 10% hydrochloric acid medium containing 2% ascorbic acid and 9% potassium iodide by a 5% solution of tri-n-octylphosphine oxide in 4-methylpentan-2-one (MIBK). The MIBK-extract containing the silver is then nebulized directly into an atomic-absorption flame. The sensitivity for the determination of silver in MIBK is about 6 times that for aqueous media. The proposed technique is accurate, rapid, and has a standard deviation of +/- 0.025 ppm at the 1 ppm level. The limit of detection is 0.2 ppm of silver. The method is also applicable to a number of elements in aluminium- and iron-base alloys.

Burke KE

1974-06-01

234

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

2003-01-01

235

Influences of pulsed current tungsten inert gas welding parameters on the tensile properties of AA 6061 aluminium alloy  

International Nuclear Information System (INIS)

Medium strength aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. In any structural application of this alloy consideration its weldability is of utmost importance as welding is largely used for joining of structural components. The preferred welding process of aluminium alloy is frequently tungsten inert gas (TIG) welding due to its comparatively easier applicability and better economy. In the case of single pass TIG welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to study the influence of pulsed current TIG welding parameters on tensile properties of AA 6061 aluminium alloy weldments.

2007-01-01

236

Wear behaviour of high tensile strength aluminium alloys under dry lubricated conditions  

Energy Technology Data Exchange (ETDEWEB)

The wear behaviour of high tensile strength aluminium alloys was studied by rubbing them against a steel counterface under both dry and lubricated conditions. The test materials used were extruded Al-Zn-Mg alloy (7004-T6) and Al-Cu-Mg alloy (2024-T4). In laboratory air, the mild wear rates of both aluminium alloys were almost the same. However, 7004-T6 easily caused severe wear at high contact loads. In paraffin oil, the wear rates were about 1/10 the wear rates under dry conditions. The wear rate of 7004-T6 was greater than that of 2024-T4, but the difference became smaller with increasing contact load. 7004-T6 showed a lower friction coefficient compared with 2024-T4 at every contact load. When the wear rates were compared at the same friction force, the rate of 7004-T6 was greater than that of 2024-T4 at every friction force. This result was due to the difference in wear particle sizes. Namely, for 7004-T6, wear cracks which would propagate in the sliding direction occurred and large and elongated wear particles were detached. For 2024-T4 many small wear cracks were caused, resulting in detachment of small wear particles. These differences in wear behaviour seem to be affected by the material properties which are responsible for the difference in fatigue behaviour rather than tensile strength or hardness. The results of this study are useful for selecting materials for machine design and of interest in understanding the relationship between wear and fatigue. (orig.)

Iwai, Yoshiro [Dept. of Mechanical Engineering, Fukui Univ. (Japan); Hou, Weiya [Dept. of Mechanical Engineering, Fukui Univ. (Japan); Honda, Tomomi [Dept. of Mechanical Engineering, Fukui Univ. (Japan); Yoneda, Hidetomo [Tsudakoma Corp., Nomachi, Kanazawa (Japan)

1996-08-01

237

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

International Nuclear Information System (INIS)

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

2004-10-04

238

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

International Nuclear Information System (INIS)

[en] 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

1980-01-01

239

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; Oluseyi O. Ajayi

2012-01-01

240

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

Energy Technology Data Exchange (ETDEWEB)

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 Ti{sub 2}Ni electrodes increases significantly with cobalt addition. Charge/discharge cycle life measurements show that the specific capacity of Ti{sub 2}Ni electrodes increases with cobalt addition, reaches a maximum at a cobalt content of 0.67 at. % (Ti{sub 2}Ni{sub 0.98}Co{sub 0.02}), and then falls with further addition. (2) The cycle life of Ti{sub 2}Ni 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 Ti{sub 2}Ni hydrogen storage alloy is effective in increasing the specific capacity and the charge/discharge cycle life of the electrode

Liu, H.K.; Luan, B.; Cui, N.; Dou, S.X. [Univ of Wollongong, Wollongong, NSW (Australia). Centre for Supercondcuting and Electronic Materials

1996-12-31

 
 
 
 
241

Radiation damage of binary alloys on the base of aluminium during neutron irradiation  

International Nuclear Information System (INIS)

[en] Results of investigation of peculiarities of radiation damage of binary alloys of aluminium with magnesium and zinc, which are characteristic alloying or impurity elements of industry alloys on the base of Al are presented. The samples of Al and its binary alloys Al-Mg and Al-Zp are irradiated by neutrons in reactor at 100+-25 deg C temperature. Bose of neutron irradiation with E>0.1 MeV energy is equal to 2.6x1024 n/m2, and by thermal - 17x1025 n/m2. Microhardness and angular correlation of 2?-irradiation at annihilation of positrons are measured after irradiation and during the process of isochronous annealing in 25-450 deg C temperature range. It is found that neutron irradiation results in narrowing of correlation curves and increase of microhardness. Recovery of the microhardness and annihilation characteristics during isochronous annealing is observed in 100-300 deg C temperature range +RT

1983-01-01

242

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

International Nuclear Information System (INIS)

[en] 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.)

2007-01-01

243

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

244

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ) composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting ...

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

245

Neutralization of the negative influence of iron and silicon on the mechanical properties of aluminium casting alloys  

International Nuclear Information System (INIS)

[en] In most of casting aluminium alloys iron is a harmful impurity due to the appearance of rough particles with needle, plate or sceleton shapes of intermetallic compounds during crystallization. As a result of it the plasticity, fracture toughness and sometimes the strength are decreased

1990-01-01

246

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

Energy Technology Data Exchange (ETDEWEB)

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

Kapusta, B. [CEA Saclay, DEN/DANS/DMN/SEMI/LM2E, 91 - Gif-sur-Yvette (France); Wintergerst, M. [CEA Saclay, DEN/DANS/DMN/SEMI/LCMI, 91 - Gif-sur-Yvette (France); Dacheux, N. [Universite de Montpellier, ICSM-Paniscoule, Centre de Marcoule, 30 - Bagnols-sur-Ceze (France); Datcharry, F.; Herms, E. [CEA Saclay, DEN/DANS/DPC/SCCME/LECA, 91 - Gif-sur-Yvette (France)

2009-07-01

247

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

International Nuclear Information System (INIS)

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

2011-09-01

248

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.

2007-03-30

249

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.

2005-12-15

250

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)

1980-01-01

251

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

International Nuclear Information System (INIS)

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

2004-01-01

252

Modelling of plastic flow localisation and damage development in friction stir welded 6005A aluminium alloy using physics based strain hardening law  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Plastic flow localisation and ductile failure during tensile testing of friction stir welded aluminium specimens are investigated with a specific focus on modelling the local, finite strain, hardening response. In the experimental part, friction stir welds in a 6005A-T6 aluminium alloy were prepared...

Nielsen, K. L.; Pardoen, Thomas; Tvergaard, V.; de Meester, B.; Simar, Aude

253

Microstructural evolution and properties of friction stir welded aluminium alloy AA2219  

International Nuclear Information System (INIS)

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

2007-01-01

254

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

International Nuclear Information System (INIS)

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

2006-01-01

255

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

Science.gov (United States)

The present study examines a friction stir welded 2017A aluminium alloy. Transmission electron microscope investigations of the weld nugget revealed the average grain size of 5 microm, moderate density of dislocations as well as the presence of nanometric precipitates located mostly in grains interiors. Scanning electron microscope observations of fractures showed the presence of ductile fracture in the region of the weld nugget with brittle precipitates in the lower part. The microhardness analysis performed on the cross-section of the joints showed fairly small changes; however, after the artificial ageing process an increase in hardness was observed. The change of the joint hardness subject to the ageing process indicates partial supersaturation in the material during friction stir welding and higher precipitation hardening of the joint. PMID:20500429

Mroczka, K; Dutkiewicz, J; Pietras, A

2010-03-01

256

Creep rupture strengths up to 100.000 hours for aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

In previous papers creep rupture data for aluminium alloys were evaluated. Requests from the European standardisation suggest that values for 100 000 h should be derived. It is the purpose of the present paper to provide these values. The extrapolation of the creep rupture strength is performed with four time-temperature parameters (TTP). The final result is computed as the average between the four TTPs, including only those with a correct physical behaviour. By using four TTPs it is possible to estimate the error in the extrapolated values as the maximum difference between the TTP methods. In spite of the fact that extended extrapolation is required to derive 100 000 h rupture strength values the different methods show in general consistent results indicating that these values can be used as approximate characteristic creep rupture strengths. (orig.)

Sandstroem, R. [Royal Inst. of Tech., Applied Materials Technology, Stockholm (Sweden)]|[Swedish Inst. of Metals Research, Stockholm (Sweden)

1996-12-01

257

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

International Nuclear Information System (INIS)

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

2010-05-25

258

Recrystallisation behaviour a commercial pure and AlMn aluminium alloy after cyclic and monotonic torsion  

Energy Technology Data Exchange (ETDEWEB)

Monotonic and cyclic torsion was used to investigate the effects of strain path on the development of as the as-deformed and recrystallised microstructure of two aluminium alloys (AA3103 and AA1050). Upon reversal of the torsional direction, the flow stress rapidly reached the same steady state level and grain structure, as those prior to strain reversal. However, monotonic and cyclic deformation to same net strain led to differences in texture and misorientation distribution. The recrystallised grain size after cyclic deformation was larger than that due to monotonic deformation to the same net strain. This effect is due to a combination of a reduced driving pressure due to a lower fraction of high angle subgrain boundaries and a reduction of the density of favourable nucleation sites. The latter was due to a reduced grain boundary area and a weakening of the deformation zones surrounding the hard intermetallic particles in the test materials. (orig.)

Valle, R.; Nes, E. [Norwegian Univ. of Science and Technology, Dept. Materials Technology and Electrochemistry, Trondheim (Norway); Zwaag, S. van der [Delft Univ. of Technology, Dept. Materials Science, Delft (Netherlands)

2002-07-01

259

Hot-crack test for aluminium alloys welds using TIG process  

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

260

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

 
 
 
 
261

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

International Nuclear Information System (INIS)

[en] 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)

2009-01-01

262

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

International Nuclear Information System (INIS)

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

2011-01-01

263

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

UK PubMed Central (United Kingdom)

Ultrasonic fatigue testing equipment is presented that is capable of performing constant amplitude (CA) and variable amplitude (VA) experiments at different constant load ratios. This equipment is used to study cyclic properties of aluminium alloy 2024-T351 in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regime at load ratios R=-1 and R=0.5. CA loading does not reveal a fatigue limit below 10(10)cycles. Cracks leading to VHCF failure start at broken constituent particles. Specimens that survived more than 10(10)cycles at R=-1 contain non-propagating cracks of lengths below grain size. Resonance frequency and nonlinearity parameter ?rel show changes of vibration properties of specimens at low fractions of their VHCF lifetime. VA lifetimes are measured in the HCF and VHCF regime and compared with Miner calculations. Damage sums decrease with decreasing load (and increasing mean lifetimes) and are lower for R=0.5 than R=-1.

Mayer H; Fitzka M; Schuller R

2013-12-01

264

Thick gradient layers prepared by plasma-based ion implantation on 2024 aluminium alloy  

International Nuclear Information System (INIS)

[en] AlN/Ti/TiN/DLC layers more than 1 ?m thick have been prepared by plasma-based ion implantation sequentially with nitrogen/titanium/nitrogen and titanium/carbon on 2024 aluminium alloy. On the basis of our previous AlN/Ti/TiN/DLC layers, new AlN/Ti/TiN/DLC layers thicken by thickening the 'TiN' layer and the diamond-like (DLC) film. The structures of the new layers have been characterized by XPS, AFM and Raman spectrum. The new layers exhibit improved composition and structure gradients at the interface in addition to a thicker 'TiN' layer and DLC film than the previous ones and hence display significant improvements in surface hardness and tribological properties. Also, their surface topography, DLC structure, nanohardness, stress and tribological properties as a function of the DLC film thickness have been discussed

2007-08-21

265

Hybrid modelling methodology applied to microstructural evolution during hot deformation of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

This paper considers how data based neurofuzzy modelling techniques for the poorly understood relationships between changing process histories and the evolution of the internal state variables of dislocation density, subgrain size and subgrain boundary misorientation can be combined with physically-based models to investigate the effects of the internal state variables on the flow stress and recrystallisation behaviour. The model uses genetic algorithms to optimise the constants and is validated for data on a range of aluminium-magnesium alloys of both high and commercial purity. It is shown that this hybrid modelling methodology supported by a knowledge base offers a flexible way to develop the microstructural modelling as more data and better understanding of the evolution of the internal state variables become available. (orig.)

Sellars, C.M.; Abbod, M.F.; Zhu, Q.; Linkens, D.A. [Inst. for Microstructural and Mechanical Process Engineering: The Univ. of Sheffield, Sheffield (United Kingdom)

2003-07-01

266

Thick gradient layers prepared by plasma-based ion implantation on 2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

AlN/Ti/TiN/DLC layers more than 1 {mu}m thick have been prepared by plasma-based ion implantation sequentially with nitrogen/titanium/nitrogen and titanium/carbon on 2024 aluminium alloy. On the basis of our previous AlN/Ti/TiN/DLC layers, new AlN/Ti/TiN/DLC layers thicken by thickening the 'TiN' layer and the diamond-like (DLC) film. The structures of the new layers have been characterized by XPS, AFM and Raman spectrum. The new layers exhibit improved composition and structure gradients at the interface in addition to a thicker 'TiN' layer and DLC film than the previous ones and hence display significant improvements in surface hardness and tribological properties. Also, their surface topography, DLC structure, nanohardness, stress and tribological properties as a function of the DLC film thickness have been discussed.

Liao, J X; Tian, Z; Li, E Q; Xu, J; Jin, L; Yang, H G [Research Institute of Electronic Science and Technology, University of Electronic Science and Technology of China, ChengDu 610054 (China)

2007-08-21

267

Mechanism and possible solution for transverse solidification cracking in laser welding of high strength aluminium alloys  

International Nuclear Information System (INIS)

In laser and hybrid laser/arc welding of high strength aluminium alloys, a large number of transverse cracks were found in the weld fusion zone. The cracking behaviour was evaluated experimentally and scanning electron microscopy images of crack surfaces confirmed that the cracks occurred when the weld fusion zone was in the semi-solid state. Thermal histories in the workpiece under representative welding conditions were measured and constitutive modelling of thermo-mechanical behaviour in the weld was performed. It was found that the cracking is related to the elongated temperature distribution in the welding direction, which induces a transverse tensile strain in the weld fusion zone during the cooling phase. One of the possible solutions to the cracking problem is to use an additional heat source to alter the temperature distribution and thus to reduce the cracking tendency. The effect of welding with an appropriately placed secondary heat source was verified by experimental tests.

2006-08-15

268

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

269

A new model for prediction of dispersoid precipitation in aluminium alloys containing zirconium and scandium  

Energy Technology Data Exchange (ETDEWEB)

A model has been developed to predict precipitation of ternary Al{sub 3}(Sc, Zr) dispersoids in aluminium alloys containing zirconium and scandium. The model is based on the classical numerical method of Kampmann and Wagner, extended to predict precipitation of a ternary phase. The model has been applied to the precipitation of dispersoids in scandium containing AA7050. The dispersoid precipitation kinetics and number density are predicted to be sensitive to the scandium concentration, whilst the dispersoid radius is not. The dispersoids are predicted to enrich in zirconium during precipitation. Coarsening has been investigated in detail and it has been predicted that a steady-state size distribution is only reached once coarsening is well advanced. The addition of scandium is predicted to eliminate the dispersoid free zones observed in scandium free 7050, greatly increasing recrystallization resistance.

Robson, J.D

2004-04-05

270

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-05-01

271

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

UK PubMed Central (United Kingdom)

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

Mroczka K; Dutkiewicz J; Pietras A

2010-03-01

272

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

Science.gov (United States)

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

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

2010-12-09

273

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

UK PubMed Central (United Kingdom)

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

Uli N; Kuppuswamy R; Amran MF

2011-05-01

274

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

International Nuclear Information System (INIS)

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

2010-01-01

275

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Camadas de conversão ricas em Ce têm sido investigadas como possíveis substitutas às camadas de cromo na proteção contra a corrosão de ligas de alumínio. Neste trabalho a microestrutura e o comportamento eletroquímico da liga de alumínio 2024 com e sem camada de conversão de Ce foram investigados utilizando MEV-EDS e EIE. Resultados de EDS mostraram que a presença de partículas de Cu depositadas sobre a superfície da liga estimula a formação da camada de c (more) onversão aumentando a intensidade dos picos de Ce no espectro EDS. Os experimentos de EIE mostraram que a presença da camada de conversão aumenta o valor da impedância, e que a evolução das características da camada pode ser seguida pelas mudanças que ocorrem no ângulo de fases em alta freqüência. As curvas potentiodinâmicas mostraram que a proteção conferida pela camada de conversão deve-se ao bloqueio da reação de redução do oxigênio. Abstract in english Cerium conversion layers (CeCL) have been investigated as a replacement for chromium conversion layers to protect Al alloys against corrosion. In this work the microstructure and the electrochemical behaviour of aluminium alloy 2024 with and without CeCL were investigated using, respectively, SEM-EDX and EIS. EDX results have shown that the presence of dispersed plated Cu particles on the alloy surface enhances the formation of the CeCL increasing the intensity of Ce peak (more) s in the EDX spectra. EIS measurements on conversion-coated samples have shown that the presence of the layer increases the impedance, and that its presence is detected by the presence of a high frequency time constant. Results of potentiodynamic experiments have shown that the corrosion protection afforded by the conversion layer is due to the hindrance of the oxygen reduction reaction and that the pitting potential of the alloy is not changed.

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

2003-08-01

276

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

International Nuclear Information System (INIS)

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

2003-12-20

277

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-03-01

278

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

Directory of Open Access Journals (Sweden)

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

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

2006-01-01

279

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

Science.gov (United States)

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

Birol, Yücel; Birol, Feriha

2007-04-01

280

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

Energy Technology Data Exchange (ETDEWEB)

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

Owen, R.A.; Preston, R.V.; Withers, P.J.; Shercliff, H.R.; Webster, P.J

2003-04-15

 
 
 
 
281

Erosion and corrosion characteristics of an aluminium alloy-alumina fibre composite  

Energy Technology Data Exchange (ETDEWEB)

The present paper describes the erosion-corrosion behaviour of an aluminium alloy (BS:LM 5) and its composite containing 10 vol.% alumina fibres. Tests were performed in 3% NaCl solution with and without sand particles (10 wt.%) using the rotating sample method. Salt immersion and potentiodynamic polarization studies of the specimens were also carried out in 3% NaCl solution. Both the tests showed increased weight loss with test duration. The composite suffered from more material loss than the base alloy. The erosion-corrosion test revealed a significantly higher extent of weight loss in the specimens as compared to the immersion test in an identical electrolyte (3% NaCl). Corrosion of the samples proceeded by the breaking-off of the oxide layer followed by nucleation of micropits and crater formation. Further, the composite suffered from additional attack by the electrolyte at the dispersoid-matrix interfaces. In erosion-corrosion tests, weight loss of the samples was accelerated by the impingement of the electrolyte at corroded sites leading to easy removal of corrosion products from the surface. The presence of sand particles in the electrolyte further accelerated the process of material removal due to rapid formation of pits and craters and (partial) removal of alumina fibres from the surface. Four stages of erosion-corrosion, namely (1) incubation period, (2) accelerated erosion-corrosion, (3) deceleration period and (4) steady state material loss, were observed during the erosion-corrosion tests. (orig./MM)

Saxena, M. (Regional Research Lab. (CSIR), Bhopal (India)); Modi, O.P. (Regional Research Lab. (CSIR), Bhopal (India)); Prasad, B.K. (Regional Research Lab. (CSIR), Bhopal (India)); Jha, A.K. (Regional Research Lab. (CSIR), Bhopal (India))

1993-10-01

282

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

283

Oxide growth on aluminium alloys in the presence of ammonium fluoborate  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

284

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

International Nuclear Information System (INIS)

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

2003-04-15

285

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

DEFF Research Database (Denmark)

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

Jones, A.R.; Hansen, Niels

1981-01-01

286

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

International Nuclear Information System (INIS)

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

2012-01-01

287

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

Directory of Open Access Journals (Sweden)

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

L. Blacha; J. Mizera; P. Fol?ga

2014-01-01

288

Aluminium and copper analysis in metallic alloys by neutron activation analysis from an 241 Am-Be source  

International Nuclear Information System (INIS)

Aluminium and copper have been determined in aluminium alloys by the method of activation with neutrons from an 241 Am-Be source of intensity 9,8 x 106 n/s. The activity induced due to reactions 27 Al (n, ?)28 Al and 63 Cu (n, ?)64 Cu have been measured with a NaI (Tl) detector coupled to a single channel system. In order to obtain the samples and standards of about the same composition, the material to be irradiated was powdered. In view of low intensity of neutron source it was necessary to use samples of up to 50 g. A series of preliminary irradiations were carried out to ensure that the geometry for the irradiation and for the counting are reproducible. The results have been compared with those obtained by chemical methods. Assuming that the results obtained by chemical method is exact, a maximum relative error of 3,6% is obtained by this method. The method has a good reproducibility. The time needed for analysis of aluminium and copper are 18 min and 2 hours 40 minutes respectively. Four different samples were analysed. The average of five measurements for one of the samples was: 88.0% for aluminium and 10.0% for copper. The standard deviation and coefficient of variation were 0,8 and 1.0% for aluminium and 0,2 and 2.0% for copper. (author)

1980-01-01

289

An investigation of serrated yielding in 5000 series aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

The effect of different thermal treatment temperatures (from 472 to 783 K) on the characteristics of serrated yielding of three commercial aluminum alloys, AA5052, AA5754 and AA5182, was investigated. In the high temperature treatment range, the stress drop ({delta}{sigma}) decreases with increasing thermal treatment temperature. This is the result of an increase in grain size as the thermal treatment temperature increases and can be explained from the solute-dislocation interaction model. For these alloys without any thermal heat treatment after cold rolling and those with a 472 K heat treatment after cold rolling, there is a critical strain before the onset of serrated yielding. The critical strain is larger for those after 472K heat-treatment as compared to those without heat-treatment. This result can be explained by the precipitation of Mg atoms from the solid solution when heat-treated at 472 K.

Wen Wei; Morris, J.G

2003-08-15

290

An investigation of serrated yielding in 5000 series aluminum alloys  

International Nuclear Information System (INIS)

The effect of different thermal treatment temperatures (from 472 to 783 K) on the characteristics of serrated yielding of three commercial aluminum alloys, AA5052, AA5754 and AA5182, was investigated. In the high temperature treatment range, the stress drop (??) decreases with increasing thermal treatment temperature. This is the result of an increase in grain size as the thermal treatment temperature increases and can be explained from the solute-dislocation interaction model. For these alloys without any thermal heat treatment after cold rolling and those with a 472 K heat treatment after cold rolling, there is a critical strain before the onset of serrated yielding. The critical strain is larger for those after 472K heat-treatment as compared to those without heat-treatment. This result can be explained by the precipitation of Mg atoms from the solid solution when heat-treated at 472 K.

2003-08-15

291

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

Energy Technology Data Exchange (ETDEWEB)

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

Trinckauf, K.; Pesicka, J.; Schlesier, C.; Nembach, E. (Inst. fuer Metallforschung, Univ. Muenster (Germany))

1992-06-16

292

The numerical analysis of the formability of aluminium alloy sheet in complex shape box deep drawing forming  

Energy Technology Data Exchange (ETDEWEB)

This paper analyzes the formability of aluminium alloy sheet X611-T4 in complex shape box deep drawing by means of a ductile fracture criterion, and reveals the effect of shear stress in blank plane on the formability of blank, which at different-radius corner. The obtained results are as follows: (1) the simulated thickness distribution is in agreement with the measured value; (2) the critical punch stroke and the fracture initiation position predicted by the criterion are consistent with the experiment; (3) the effect of friction coefficient, blank holder force and cut-length on the formability is obvious, among which the effect of cut-length is the most remarkable. The result proves that reasonable modification of the processing parameters can obviously increase the formability of aluminium alloy sheet X611-T4. (orig.)

Yu, Z.Q.; Lin, Z.Q.; Zhao, Y.X. [School of Mech. Eng., Shanghai Jiao Tong Univ., Shanghai, SH (China)

2004-07-01

293

An experimental investigation of cyclic hardening of 316 stainless steel and of 2024 aluminium alloy under multiaxial loading  

International Nuclear Information System (INIS)

[en] This paper is concerned with the experimental behavior of a 316 stainless steel and a 2024 aluminium alloy at room temperature and under complex nonproportional strainings in tension-torsion. The basic features of this behavior are underlined and their interactions emphasized. It is observed that the response of these materials under general loading paths is a balance between hardening and softening occurring respectively when the nonproportionality of the straining path is increased or decreased

1989-01-01

294

An experimental investigation of cyclic hardening of 316 stainless steel and of 2024 aluminium alloy under multiaxial loading  

Energy Technology Data Exchange (ETDEWEB)

This paper is concerned with the experimental behavior of a 316 stainless steel and a 2024 aluminium alloy at room temperature and under complex nonproportional strainings in tension-torsion. The basic features of this behavior are underlined and their interactions emphasized. It is observed that the response of these materials under general loading paths is a balance between hardening and softening occurring respectively when the nonproportionality of the straining path is increased or decreased.

Benallal, A.; Le Gallo, P.; Marquis, D. (Ecole Normale Superieure de l' Enseignement Technique, 94 - Cachan (France). Lab. de Mecanique et Technologie)

1989-06-01

295

Determination of optimum conditions range in diffusion welding of sTS-19 piezoelectric ceramics with AMg6 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

A possibility of production of a high-quality joint of TsTS-19 piezoelectric ceramics with the AMg6 aluminium alloy is studied by the method of diffusion welding. The effect of welding regimes upon the joint qualily is investigated. The range of the diffusion welding optimum regimes permitting to obtain piezoelectric transducers, which can operate at vibration loadings and cyclic thermal shocks in a temperature range from - 196 deg C up to +100 deg C, is determined.

Kazakov, N.F. (Moskovskij Aviatsionnyj Tekhnologicheskij Inst. (USSR)); Novikov, V.G.; Ekimov, A.I.; Kravchenko, V.E. (Krasnoyarskij Politekhnicheskij Inst. (USSR))

1982-08-01

296

Transmission lines with thermo-resistant Aluminium alloy conductors; Linhas de transmissao com condutores de liga de Al termorresistente  

Energy Technology Data Exchange (ETDEWEB)

Many attempts were already made with objective of improving electric power transmission capacity through the conductors. At Transmission Lines, where Al 1350 is widely used, the ampacity is limited by the conductor temperature at 90 deg C on normal operation regimen. Concerning to this condition, it was developed an Aluminium Alloy which was named Thermo-resistant. Its conductor temperature on normal operation regimen could be increased until 150 deg C, without mechanical characteristics losses. (author) 4 refs., 4 figs., 3 tabs.

Ueda, Sidnei [Furukawa Industrial S.A., Lorena, SP (Brazil)

1997-12-31

297

Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754  

Science.gov (United States)

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

Hausöl, T.; Höppel, H. W.; Göken, M.

2010-07-01

298

Microstructure and mechanical properties of accumulative roll bonded aluminium alloy AA5754  

International Nuclear Information System (INIS)

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

2010-07-01

299

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

DEFF Research Database (Denmark)

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

Daviðsdóttir, Svava; Soyama, Juliano

2011-01-01

300

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

International Nuclear Information System (INIS)

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

2001-01-01

 
 
 
 
301

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-07-01

302

Experiment planning in the investigation of the heat-resistance of the iron-nickel-chromium-silicon-aluminium system alloys  

International Nuclear Information System (INIS)

[en] The general laws governing variation in the heat-resistance within the temperature range of 1100 to 1300 deg C, of alloys of iron-nickel-chromium-silicon-aluminium system have been examined depending on their composition. The heat resistance of the alloys was assessed after 500-hour holding according to an increase in the mass of cylindrical samples. Using the experimental data as the basis, the heat-resistant models were developed according to the composition of alloys. It has been established that the alloy containing 52.7% Ni; 22.4% Cr; 1.8% Si; 2.49% Al (the balance is iron), is best with regard to its heat resistance at a temperature of 1300 deg C

1978-01-01

303

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

International Nuclear Information System (INIS)

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

1997-01-01

304

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-01-01

305

EVALUATION OF PARAMETERS OF FRICTION STIR WELDING FOR ALUMINIUM AA6351 ALLOY  

Directory of Open Access Journals (Sweden)

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

AHMED KHALID HUSSAIN; SYED AZAM PASHA QUADRI

2010-01-01

306

Experimental and numerical evaluation of friction stir welds of AA6061-T6 aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Friction stir welding is a relatively new joining process, which involves the joining of metals without fusion or filler materials. The amount of the heat conducted into the work piece dictates a successful process which is defined by the quality, shape and microstructure of the processed zone, as well as the residual stress and the distortion of the work piece. The amount of the heat gone to the tool dictates the life of the tool and the capability of the tool to produce a good processed zone. Hence, understanding the heat transfer aspect of the friction stir welding is extremely important for improving the process. Many research works were carried out to simulate the friction stir welding using various soft wares to determine the temperature distribution for a given set of welding conditions. Very few attempted to determine the maximum temperature by varying the input parameters using ANSYS. The objective of this research is to develop a finite element simulation of friction stir welding of AA6061-T6 Aluminium alloy. Trend line equations are developed for Thermal conductivity, specific heat and density to know the relationship of these factors with peak temperature. Tensile and hardness values for the welded specimens are found for different rotational speed and feed. Variation of temperature with input parameters is also observed. The simulation model is tested with experimental results. The results of the simulation are in good agreement with that of experimental results.

P. Prasanna; B. Subba Rao; G. Krishna Mohana Rao; Anjaneya Prasad

2010-01-01

307

Influence of dispersoids size and distribution on recrystallization kinetics of an AA1050 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

The effect of dispersoids on the static recrystallization kinetics of AA1050 commercial purity aluminium has been investigated. The size and distribution of the dispersoids in this alloy have been studied by means of SEM-FEG and TEM. In the as cast structure, two types of dispersoids have been found: 'big' ones (size {proportional_to}0.5 {mu}m) and 'small' ones' (size {proportional_to}10 nm), observable only by TEM. A TTT diagram for the 'big' dispersoids has been generated and based on that, three preheat treatments were selected in order to generate three different size distributions of the dispersoids. Samples of these three materials have been hot deformed in plane strain compression and quenched. They were subsequently annealed under various conditions. The small dispersoids proved to slow down the recrystallization kinetics rather drastically. Medium sized dispersoids (between 25 and 100 nm) did not changed considerably the kinetics. The underlying mechanisms responsible for these observations are discussed. (orig.)

Verlinden, B.; Ratchev, P. [Katholieke Univ. Leuven, Dept. of Metallurgy and Materials Engineering, Leuven (Belgium); Broeck, R. van den [Corus Aluminium N.V., Duffel (Belgium); Liu, C. [Corus RDT, CA IJmuiden (Netherlands)

2001-07-01

308

Effect of friction stir lap welding conditions on joint strength of aluminium alloy 6060  

Energy Technology Data Exchange (ETDEWEB)

Strength of lap joints made by friction stir welding (FSW) depends strongly on how material flows forming the weld nugget zone during FSW and also on how the joint is loaded during testing. Understanding of this processing-property relationship is currently inadequate. In this study, the effects of pin length, welding speed and rotation rate on weld strength using aluminium alloy 6060 were investigated. It has been found that the pin length needed to be slightly greater than the thickness of the sheet for an adequate joint to be established. However, further increase in pin length did not benefit the joint strength. The major factor affecting joint strength has been found to be the rotation speed. An increase in rotation speed resulted in lowering the joint strength. Various modes of fracture have been observed and these modes relate to the degree of hooking and softening. Explanation of how the speed values relate to heat input and material flow and then to the joint strength is given.

Yazdanian, S; Chen, Z W, E-mail: syazdanian@aut.ac.nz [Department of Mechanical and Manufacturing Engineering, AUT University, Auckland (New Zealand)

2009-08-15

309

Effect of friction stir lap welding conditions on joint strength of aluminium alloy 6060  

International Nuclear Information System (INIS)

[en] Strength of lap joints made by friction stir welding (FSW) depends strongly on how material flows forming the weld nugget zone during FSW and also on how the joint is loaded during testing. Understanding of this processing-property relationship is currently inadequate. In this study, the effects of pin length, welding speed and rotation rate on weld strength using aluminium alloy 6060 were investigated. It has been found that the pin length needed to be slightly greater than the thickness of the sheet for an adequate joint to be established. However, further increase in pin length did not benefit the joint strength. The major factor affecting joint strength has been found to be the rotation speed. An increase in rotation speed resulted in lowering the joint strength. Various modes of fracture have been observed and these modes relate to the degree of hooking and softening. Explanation of how the speed values relate to heat input and material flow and then to the joint strength is given.

2009-01-01

310

Analysis of FSW welds made of aluminium alloy AW6082-T6  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is to analyze the results of tests on the mechanical properties and microstructural changes in Friction Stir Welds in the aluminium alloy 6082-T6 in function of varying process parameters.Design/methodology/approach: : the produced tensile strength of the produced welds was measured and the correlation with process parameter was assessed. The welds’ microstructure in various zones was analyzed using an optical microscope. Microhardness measurements were performed on the welds’ cross-sections.Findings: a tendency was observed of the mechanical resistance of test welds to increased with the increase of travel (welding) speed, maintaining constant rotational speed. Hardness decrease was observed in weld nugget and heat affected zone, of entity inferior that that of fusion welds. Origins of tunnel (worm hole) defects were found and analyzed.Research limitations/implications: various combinations pf process parameters were used to produce the test welds, but without the possibility of controlling the downward force. Further extension of applicable parameters combinations should be examined.Practical implications: the increase of mechanical resistance with increasing welding speed offers an immediate economic return, as the process efficiency is increased.Originality/value: information contained herein can be useful to further investigate on the possibility of improving the properties of FSW welds, as well as the efficiency of the process.

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

2007-01-01

311

Micromechanical aspects of fatigue in a MIG welded aluminium airframe alloy  

International Nuclear Information System (INIS)

Short crack fatigue behaviour of a metal inert gas (MIG) welded 2024-T351 aluminium alloy has been studied in terms of crack initiation and propagation, and the microstructural features of the weld. Extensive crack initiation was noted within the weld fusion zone. Relatively small interdentritic defects are seen to be more damaging (in initiating cracks) than the larger gas bubble defects that exist in this region. Cracks were also seen to initiate within the weld heat affected zone where tensile residual stresses were found to be high, however, rapid crack growth and coalescence within the fusion zone is seen to dominate failure. Multiple crack interactions are seen to have a significant effect on failure up to relatively large crack lengths (of the order of the fusion zone width), enhancing the variability in short crack growth. Secondary electron and back-scattered electron imaging, in association with electron back-scattered diffraction (EBSD) mapping, were carried out on failed samples to assess the associated microstructural interactions.

2005-10-25

312

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

Science.gov (United States)

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

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

2013-03-01

313

Experimental investigations of visco-plastic properties of the aluminium and tungsten alloys used in KE projectiles  

Directory of Open Access Journals (Sweden)

Full Text Available The main aim of studies on dynamic behaviour of construction materials at high strain rates is to determine the variation of mechanical properties (strength, plasticity) in function of the strain rate and temperature. On the basis of results of dynamic tests on the properties of constructional materials the constitutive models are formulated to create numerical codes applied to solve constructional problems with computer simulation methods. In the case of military applications connected with the phenomena of gunshot and terminal ballistics it’s particularly important to develop a model of strength and armour penetration with KE projectile founded on reliable results of dynamic experiments and constituting the base for further analyses and optimization of projectile designs in order to achieve required penetration depth. Static and dynamic results of strength investigations of the EN AW-7012 aluminium alloy (sabot) and tungsten alloy (penetrator) are discussed in this paper. Static testing was carried out with the INSTRON testing machine. Dynamic tests have been conducted using the split Hopkinson pressure bars technique at strain rates up to 1,2 ? 104s?1 (for aluminium alloy) and 6 ? 103s?1 (for tungsten alloy).

Kruszka L.; Magier M.

2012-01-01

314

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

International Nuclear Information System (INIS)

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

2007-06-30

315

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

Directory of Open Access Journals (Sweden)

Full Text Available The usage of aluminium and its alloys have increased in many applications and industries over the decades. The automotive industry is the largest market for aluminium castings and cast products. Aluminium is widely used in other applications such as aerospace, marine engines and structures. Parts of small appliances, hand tools and other machinery also use thousands of different aluminium castings. The applications grow as industry seeks new ways to save weight and improve performance and recycling of metals has become an essential part of a sustainable industrial society. The process of recycling has therefore grown to be of great importance, also another aspect has become of critical importance: the achievement of quality and reliability of the products and so is very important to underst and the mechanisms of the formation of defects in aluminium melts, and also to have a reliable and simple means of detection.

M. Br?na; A. Sládek

2011-01-01

316

Nanocomposite of polypyrrole and alumina nanoparticles as a coating filler for the corrosion protection of aluminium alloy 2024-T3  

International Nuclear Information System (INIS)

[en] Aluminium (Al) alloys such as 2024-T3 are widely used in industry as low weight construction materials with excellent mechanical properties. Until recently corrosion protection of Al alloys was carried out with coatings containing hexavalent chromium (Cr6+). However, Cr6+ is a health and environmental hazard and has to be replaced. Intrinsically conducting polymer (ICP) technology is the promising alternative to chromate coating technology because of good corrosion protection properties of ICPs, their moderate cost and good environmental compatibility. In this paper we report successful attempt of making nanocomposite comprised of alumina nanoparticles modified by polypyrrole for the purpose of corrosion protection of Al alloy. Modified nanoparticles were used as coating filler. Coating was designated to perform as an active barrier to electrolyte diffusion. Properties of the coating were examined by adhesion test, electrochemical impedance spectroscopy, X-rays elemental analysis, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy

2008-06-30

317

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

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ) composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP) and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried out under different rotational speeds and friction times, while friction force (0.5 ton-force) was kept constant. Scanning electron microscopy was used to characterize the interface of the joints structure. The experimental results showed that the friction time has a significant effect on joint structure and mechanical properties.

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

2012-01-01

318

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

Science.gov (United States)

Laser surface treatment of aluminium alloy 6013, a relatively new high strength aluminium alloy, was conducted with the aim of improving the alloy's resistance to stress corrosion cracking and corrosion fatigue. In the first phase of this research, laser surface melting (LSM) of the alloy was conducted using an excimer laser. The microstructural changes induced by the laser treatment were studied in detail and characterised. The results showed that excimer LSM produced a relatively thin, non-dentritic planar re-melted layer which is largely free of coarse constituent particles and precipitates. The planar growth phenomenon was explained using the high velocity and high temperature gradient absolute stability criteria. The structure of the oxide and/or the nitride bearing film at the outmost surface of the re-melted layer was also characterised. The results of the electrochemical tests showed that the pitting corrosion resistance of the alloy could be greatly increased by excimer laser melting, especially when the alloy was treated in nitrogen gas: the corrosion current density of the N2-treated specimen was some two orders of magnitude lower than that of the air-treated specimen which was one order of magnitude lower than that of the untreated specimen. The effect of the outer surface oxide and/or nitride bearing film per se on pitting corrosion resistance was determined. The results of a Mott - Schottky analysis strongly suggest that the outer surface film, which exhibited the nature of an n-type semiconductor was responsible for the significant improvement of the corrosion resistance of the laser-treated material. Furthermore, the corrosion response of the surface film was modelled using equivalent circuits. Based on the results of the slow strain rate tensile (SSRT) and corrosion fatigue tests, the stress corrosion cracking and pitting corrosion fatigue behaviour of the excimer laser treated material was evaluated. The results of the SSRT test showed that, in terms of percentage elongation and corrosion current density, the resistance to stress corrosion cracking improved after excimer laser treatment. While the corrosion fatigue results showed that the total fatigue life of the alloy increased noticeably after laser surface treatment. However, a higher overall fatigue crack propagation rate occurred in the laser-treated material. The effect of post-treatment ageing and residual stress on fatigue strength was also investigated; the results showed that they did not have a significant influence. Recognising that the depth of the excimer laser melted layer was very shallow, typically in the range of a few micrometers, this when compared to the melt depth in the hundred micrometer range for Nd-YAG laser treatment may disadvantage excimer laser treatment. As a consequence, a 2kW high power Nd:YAG laser was employed for the LSM experiment during the second phase of this research. It was found that a totally different re-melt microstructure to that of excimer laser melting resulted from YAG laser melting: the depth of the melt pool was in the range of a few hundreds micrometers, and instead of the planar growth morphology that occurred in excimer laser melting, a fine dendritic/cellular structure was produced. Although, an AIN film was produced at the outer surface of the re-melt layer which was similar to that of excimer laser melting, the YAG laser formed film was much thicker with larger crystallines of the nitride phase. With regard to pitting corrosion resistance, although improvement was obtained after YAG laser melting, the improvement was not as significant as that which can be achieved by excimer laser melting. This is mainly because the second phase particles at the dendrite boundaries behaved as cathodic sites while the dendrite cells acted as anodic sites. The results of the equivalent circuit modelling showed that the polarisation resistance of the YAG laser formed surface film was one order of magnitude lower than that of the excimer laser formed surface film. When comparing the stress corrosion cracking resist

Xu, Wen-Long

319

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

Science.gov (United States)

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

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

2013-09-01

320

THREE DIMENSIONAL COMPLEX SHAPES ANALYSIS FROM 3D LOCAL CURVATURE MEASUREMENTS. APPLICATION TO INTERMETALLIC PARTICLES IN ALUMINIUM ALLOY 5XXX  

Directory of Open Access Journals (Sweden)

Full Text Available The studied material is a 5xxx aluminium alloys containing 2 types of intermetallic particles : Alx(Fe;Mn) and Mg2Si. It is usually used in car industry as reinforcement pieces or in packaging industry, such as bottle liquid box lid. Scanning electronic microscope coupled with EDX analysis shows complex shapes of intermetallic particles. The particle shape is obtained during the solidification of alloys. Particles fill vacant spaces between aluminium grains. Therefore final sheet properties depend on intermetallic particles shapes and notably on the matrix-particle interface properties. The goal of the present study is to classify intermetallic particles versus their shapes using local curvature information. The aluminium alloys sample is observed by X ray micro tomography performed at the ESRF. Three dimensional images are segmented, and intermetallic particles are identified in a data base. Each particle is stored as a set of voxels. The surface of each particle is meshed by a marching cubes triangular meshing with the software Amira©. A simplification of the surface is performed by an algorithm contracting the edges. Finally, principal curvatures: kmin and kmax are estimated by Amira© on each facet centre of the mesh. From the full intermetallic population, the bivariate distribution of kmin and kmax is estimated. The obtained graph kmin ¡kmax shows geometrical properties of interface portions of the surface of particles. A factorial correspondence analysis is performed to summarize the information on all intermetallic particles. In the obtained subspace, particles are classified into five shape families, in relation with their interface geometrical properties.

Estelle Parra-Denis; Nicolas Moulin; Dominique Jeulin

2007-01-01

 
 
 
 
321

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

Directory of Open Access Journals (Sweden)

Full Text Available The effect of process parameters on metallurgical properties of friction stir welded aluminium alloy 6063-O was analysed in the present study. Samples were friction stir welded under tool rotational speed of 600, 800 and 1200 rpm and traversing speed of 0.6, 0.9 and 1.2 mm sec-1, with an axial load of 8000 kg constant for all trials and the process parameters were optimized by using Taguchi orthogonal array. Optical microstructure analysis were carried out to define the metallurgical properties at various zones of friction stir welded samples (Unaffected Base Material, Heat Affected Zone, Thermo Mechanically Affected Zone and Weld Nugget Zone) and scanning electron microscopy analysis (SEM) was carried out to determine the material flow path at the heat affected zone (HAZ) and weld nugget zone (WN) of friction stir welded samples. In present work two sets of experiments were carried out on AA 6063-O one with silicon carbide powder and without silicon carbide powder. Tool used for the FSW process is high carbon steel D3 (Heat treated 58-60 HRC), the SiC powders were inserted along the breadth of the plates by making a drill of 1 mm to a depth of 15 mm. Micro hardness survey was done across the weld regions using vickers hardness test. Correlation of micro hardness tests and metallurgical properties of the friction stir weldments were studied by optical microscope analysis, scanning electron microscopy analysis and the samples were chosen for (SEM) using grey relational analysis (GRA). It was observed that the sample 9 with SiC powders, welded with a traverse speed of 1.2 mm sec-1, tool speed of 1200 rpm and axial load of 8000 Kg showed the best behavior.

A. Varun Kumar; K. Balachandar

2012-01-01

322

Fracture criteria for automobile crashworthiness simulation of wrought aluminium alloy components  

Energy Technology Data Exchange (ETDEWEB)

In automobile crashworthiness simulation, the prediction of plastic deformation and fracture of each significant, single component is critical to correctly represent the transient energy absorption through the car structure. There is currently a need, in the commercial FEM community, for validated material fracture models which adequately represent this phenomenon. The aim of this paper is to compare and to validate existing numerical approaches to predict failure with test data. All studies presented in this paper were carried out on aluminium wrought alloys: AlMgSi1.F31 and AlMgSiCu-T6. A viscoplastic material law, whose parameters are derived from uniaxial tensile and compression tests at various strain rates, is developed and presented herein. Fundamental ductile fracture mechanisms such as void nucleation, void growth, and void coalescence as well as shear band fracture are present in the tested samples and taken into consideration in the development of the fracture model. Two approaches to the prediction of fracture initiation are compared. The first is based on failure curves expressed by instantaneous macroscopic stresses and strains (i.e. maximum equivalent plastic strain vs. stress triaxiality). The second approach is based on the modified Gurson model and uses state variables at the mesoscopic scale (i.e. critical void volume fraction). Notched tensile specimens with varying notch radii and axisymmetric shear specimens were used to produce ductile fractures and shear band fractures at different stress states. The critical macroscopic and mesoscopic damage values at the fracture initiation locations were evaluated using FEM simulations of the different specimens. The derived fracture criteria (macroscopic and mesoscopic) were applied to crashworthiness experiments with real components. The quality of the prediction on component level is discussed for both types of criteria. (orig.)

El-Magd, E. [RWTH Aachen (Germany); Gese, H. [MATFEM, Munich (Germany); Tham, R. [Fraunhofer Inst. fuer Kurzzeitdynamik, Freiburg (Germany); Hooputra, H.; Werner, H. [BMW Group, Munich (Germany)

2001-09-01

323

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

Directory of Open Access Journals (Sweden)

Full Text Available Extensive solidification simulations are conducted using finite difference method on an aluminium alloy casting. Orthogonal experimental array layout is considered for running experimental simulations. Microstructural parameter Secondary Dendrite Arm Spacing (SDAS) at three different locations was 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 capacity. An Artificial Neural Network (ANN) model was developed to predict the response variable for varied input process variables. Through sensitivity analysis the influence of input process variables on output response was obtained. The results obtained from solidification simulations and ANN model are validated experimentally.

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

2010-01-01

324

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

International Nuclear Information System (INIS)

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

2012-01-01

325

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-15

326

Measurement of the residual stress field in MIG-welded Al-2024 and Al-7150 aluminium alloy compact tension specimens  

International Nuclear Information System (INIS)

[en] Neutron diffraction has been used to measure the residual-stress field in MIG-welded Al-2024 and Al-7150 aluminium alloy compact-tension (CT) specimens. The measurements were made on the POLDI time-of-flight diffractometer, which uses a multiple frame overlap method. Strains in the three principal directions of each specimen were determined from the measured lattice plane spacing as a function of position through the weld relative to stress-free reference lattice plane spacings obtained from a comb-like reference sample. The resultant calculated residual stresses are compared to those existing in the original welded plate from which the specimens were machined

2006-11-10

327

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

International Nuclear Information System (INIS)

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

2007-04-07

328

A study of the microstructures and properties of an A390. 0 aluminium alloy produced by the layer deposition process  

Energy Technology Data Exchange (ETDEWEB)

An A390.0 aluminium alloy produced by a newly developed layer deposition process was studied regarding the refinement of microstructures and the improvement of mechanical properties. The counterpart for comparison was the same alloy but cast in an iron ingot mould. The results show that silicon particles of the layer-deposited alloy are fine and uniformly distributed in the matrix. Moreover, the segregation is significantly inhibited. The silicon particles and segregation of the cast alloy are very coarse. The mechanical properties of the former also exhibit a better combination of strength and ductility. The excess dispersion strength from fine silicon particles is about 40 MPa which does not change with aging time to the first order. The ductility improvement is attributable to the fine silicon particles since they require higher strain for void nucleation. The coarsening rate of silicon particles is high for the layer-deposited alloy when homogenized at 495 C. This is because of the high interfacial energy possessed by the fine distribution. The coarsening is an Ostwald ripening process controlled by volume diffusion. (orig.)

Yeh Jienwei (Dept. of Materials Science and Engineering, National Tsing Hua Univ., Hsinchu (Taiwan, Province of China)); Tsau Chunhuei (Materials Research Labs., Industrial Technology Research Inst., Hsinchu (Taiwan, Province of China))

1993-07-05

329

Corrosion and inhibition of medium-strength aluminium alloys; Corrosion e inhibicion en aleaciones de aluminio de media resistencia  

Energy Technology Data Exchange (ETDEWEB)

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 CeCl{sub 3} and LaCl{sub 3} 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.

Davo, B.; Damborenea, J. J.

2004-07-01

330

Influence of reactor radiation on element composition and construction material content of aluminium alloy SAV-1 type  

International Nuclear Information System (INIS)

The current work is devoted to study of reactor radiation effect on both element composition and structure of aluminium alloys SAV-1. For this purpose the samples were irradiated by neutron flux in WWR-S reactor with fluences ?1018 and ?1019 neutron/cm2. Samples have been examined in X-ray microanalyzer 'Jeon' JSM 5910 IV. Data of Mg, Al, Fe, Si and Cu elements content for SAV-1 alloys before and after irradiation were obtained. It is reveled, that samples surface after irradiation is oxidizing, and local insoluble intermetallic phases of Al-Mg-Si-Fe type are dissipating by the sample large range. This is leading to essential change of element composition in different points

2007-01-01

331

Influence of cerium molybdate containers on the corrosion performance of epoxy coated aluminium alloys 2024-T3  

International Nuclear Information System (INIS)

Graphical abstract: Cerium molybdate containers loaded with 2-mercaptobenzothiazole were incorporated into epoxy coatings onto aluminium alloys 2024-T3 and investigated with respect the corrosion protection of the metallic surfaces. Highlights: ? Cerium molybdate nanocontainers loaded with corrosion inhibitor. ? Epoxy coatings including loaded nanocontainers applied to AA2024-T3. ? The loaded nanocontainers improves epoxy coatings corrosion protection properties. - Abstract: Cerium molybdate containers loaded with 2-mercaptobenzothiazole were incorporated into epoxy coatings onto aluminium alloys 2024-T3 and investigated with respect to the corrosion protection of the metallic surfaces. The coatings were deposited via the dip-coating process. The morphology of the coatings was examined by Scanning Electron Microscopy. Their composition and structure were investigated by Fourier Transform Infrared Spectroscopy and Energy Dispersive X-ray Analysis. The corrosion resistance of these coatings was investigated by using electrochemical impedance spectroscopy and open circuit potential. After exposure to 0.05 M NaCl solution for 28 days, the coatings with the loaded containers exhibit improved corrosion performance.

332

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

Science.gov (United States)

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

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

2013-05-01

333

Thermal cycling creep of a short fibre reinforced aluminium piston alloy; Thermozyklisches Kriechen einer kurzfaserverstaerkten Aluminium-Kolbenlegierung  

Energy Technology Data Exchange (ETDEWEB)

The aluminum piston alloy AlSi12CuMgNi, reinforced with Saffil trademark short fibres, is loaded in constant tension and thermally cycled between 50 and 300 C up to failure. Heating and cooling rates of 12.5 K/s are achieved by the resistance heating system of the ''Gleeble 1500'' and by cooling with pressurized air. The reinforcement with ceramic short fibres causes an increase of life time and a decrease of the minimum creep rate for all testing conditions. Compared to the unreinforced samples, the influence of heat treatment condition becomes negligible because of the short fibre reinforcement. The effect of the short fibre reinforcement can be described by modification of the isothermal creep laws. (orig.)

Schnabl, A.; Degischer, H.P. [Inst. fuer Werkstoffkunde und Materialpruefung, TU Wien (Austria)

2003-06-01

334

Characterization of friction stir welded joints of the aluminium alloy AA 2024-T3 by laser extensometry; Reibruehrschweissungen aus Aluminium charakterisieren. Lokale Dehnungsmessung mit Laserextensometer  

Energy Technology Data Exchange (ETDEWEB)

Friction stir welding (FSW) is a simple, clean and innovative solid state joining process for light metals. In contrast to conventional welding, FSW is performed at temperatures below the melting point. Therefore, detrimental microstructural changes and cracking during the solidification of the weld pool are avoided. Within certain limits, the excellent mechanical properties of friction stir welds are further improved by an increase of the welding or transverse speed. This is shown by localized strain measurements during tensile tests of friction stir welded sheet material of the aluminium alloy AA 2024-T3. The local strains are measured in the welding region and in the heat affected zone by a laser extensometer. It turned out that the increase in strength with increasing weld speed has to be related to the more homogeneous strain distribution in the welding region and heat affected zone. (orig.) [German] Das Reibruehrschweissen oder Friction Stir Welding (FSW) ist ein einfaches und sauberes Fuegeverfahren fuer Leichtmetalle. Im Gegensatz zu konventionellen Schmelz-Schweissverfahren erfolgt der FSW-Prozess bei Temperaturen unterhalb des Schmelzpunktes von Leichtmetalllegierungen, was Gefuegeveraenderungen und Rissbildungen beim Erstarren der Schmelze vermeidet. Die guten mechanischen Eigenschaften reibruehrgeschweisster Verbindungen lassen sich durch eine Erhoehung des Vorschubs weiter verbessern, wie Zugversuche an geschweissten Blechen der Aluminiumlegierung AA 2024-T3 zeigen. Ueber lokale Dehnungsmessungen im Nahtbereich wird mit dem Laserextensometer nachgewiesen, dass die Ursache der gleichzeitigen Zunahme von Festigkeit und Verformbarkeit in einem homogenen Verformungszustand liegt. (orig.)

Biallas, G. [Paderborn Univ. (Germany). Lehrstuhl fuer Werkstoffkunde; Dalle Donne, C. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany). Inst. fuer Werkstoff-Forschung

2000-07-01

335

Voprosu o prirode ehffekta Portevena-le-Shatel'e v obluchennykh alyuminievykh splavakh. (Problem about nature of Portevin-le-Chatelier effect in irradiated aluminium alloys).  

Science.gov (United States)

The influence of hardening return, deformation ageing and (gamma)-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 discontinuo...

V. N. Drobyazin S. P. Polovneva Y. Podzirej G. A. Soldatenko V. G. Vorob'ev

1991-01-01

336

Spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and other materials. Determinacion espectrofotometrica de titanio con acido ascorbico en aleaciones de base aluminio y otros materiales  

Energy Technology Data Exchange (ETDEWEB)

A spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and bauxite is described. The proposed procedures permit to determine levels of titanium down to 5.10 ''3% with a good accuracy and precision. (Author) 13 refs.

Bosch Serrat, F. (Departamento de Quimica Analitica. Facultad de Qauimica. Valencia (Spain))

1994-01-01

337

Diffusion bonding of an aluminium alloy (AA 2124) reinforced with SiC whiskers, using AL-Li interlayers (AA 8090)  

International Nuclear Information System (INIS)

The use of an AL-Li alloy as interlayer for the diffusion bonding of an aluminium matrix composite reinforced with silicon carbide whiskers has been studied. The influence of the different welding parameters on the joint microstructure and mechanical strength has also been analyzed. Besides, the failure mechanisms of shear tested joints have been investigated using fractographic techniques. (Author) 9 refs.

1994-01-01

338

Strain hardening of aluminium alloy 3004 in the deep drawing and ironing processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The evolution of material hardening resulting from the canmaking operations on aluminium beverage cans has been investigated. Tensile tests in cup walls revealed that deep drawing induced softening in the hoop direction and hardening in the meridian direction. This anisotropy is retained in the iron...

Courbon, J.; Duval, J.

339

CeO{sub 2}-filled sol-gel coatings for corrosion protection of AA2024-T3 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

Schem, M.; Schmidt, T.; Gerwann, J.; Wittmar, M.; Veith, M. [INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbruecken (Germany); Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Molchan, I.S. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)], E-mail: igor.molchan@manchester.ac.uk; Hashimoto, T.; Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Phani, A.R.; Santucci, S. [Department of Physics University of L' Aquila Via Vetoio 10, Coppito, 67010 L' Aquila (Italy); Zheludkevich, M.L. [Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

2009-10-15

340

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

International Nuclear Information System (INIS)

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

2009-01-01

 
 
 
 
341

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

International Nuclear Information System (INIS)

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

2007-04-07

342

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

Science.gov (United States)

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

Gavrus, A.; Francillette, H.

2007-04-01

343

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

Directory of Open Access Journals (Sweden)

Full Text Available The influence of in- and out- of plane constraints on the behaviour of a crack under mode I loading conditions is studied. The independence of the stress intensity tensor, with respect to the specimen thickness B shows that under loss of constraint conditions higher order members of the Williams’ tensor expansion must be considered if the experimental results for increasing apparent fracture toughness resulting from decreasing specimen thickness are to be explained. This is achieved using the constraint curves that define the intensity field tensor along the crack propagation direction and can be alternative to the T-stress approach. This approach is then applied to crack instability assessment for program compact tension (CT — positive values of T-stress) and three point bending (3PB— from negative to positive values of T-stress) specimens with different thicknesses. The theoretical results are compared with experimental ones obtained from the research program on aluminium alloy 2024.

Seitl S.; Huta? P.; García T. E.; Fernández-Canteli A.

2013-01-01

344

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

Directory of Open Access Journals (Sweden)

Full Text Available An analysis of the effects of sand casting process parameters on the ultimate tensile strength of an aluminium alloy sand casting based on the Analysis of variance (ANOVA) technique is proposed in this paper. While other casting parameters were kept constant, the selected parameters were varied and the cast specimen tested to obtain their ultimate tensile strength. Formulation of the varied effects was then made and a statistical tool selected for the analysis. The result of this work shows that the selected technique is an effective tool for analyzing sand casting process. The computed treatment mean square, response mean square and error mean square are 456.35, 57.57, and 59.8 respectively. It is concluded with 90% confidence that the mould temperature is the most significant factor which influences the casting quality in terms of strength under the specified conditions.

John O. OJI; Buliamin KAREEM; Nosa IDUSUYI

2011-01-01

345

Determination of an empirical law of aluminium and magnesium alloys absorption coefficient during Nd : YAG laser interaction  

Energy Technology Data Exchange (ETDEWEB)

Welding laser modelling requires knowledge about relative changes of many thermo-physical parameters involved in the interaction. The absorptivity of the material is one of the most important. In this study, experimental measurements of absorptivity with an integrating sphere on two alloys (aluminium and magnesium) were made. These results were compared with an analytical calculation that takes into account the trapping of the beam by multiple reflections inside the keyhole. Based on a statistical method, an empirical law is proposed connecting absorptivity with the peak power of the laser and the duration of interaction. During the interaction, two distinct phenomenologies are brought to light. A threshold is then defined after which the physical process becomes stable. Below this threshold, the measurement of absorptivity is problematic, and the values are widely dispersed.

Pierron, Nicolas [Laboratoire Laser et Traitement des Materiaux (CNRS-2604), Universite de Bourgogne, IUT Le Creusot, 71200 Creusot (France); Sallamand, Pierre [Laboratoire Laser et Traitement des Materiaux (CNRS-2604), Universite de Bourgogne, IUT Le Creusot, 71200 Creusot (France); Jouvard, Jean-Marie [Laboratoire Laser et Traitement des Materiaux (CNRS-2604), Universite de Bourgogne, IUT Le Creusot, 71200 Creusot (France); Cicala, Eugen [Mechanical Faculty, Polytechnic University, Timisoara (Romania); Mattei, Simone [Laboratoire Laser et Traitement des Materiaux (CNRS-2604), Universite de Bourgogne, IUT Le Creusot, 71200 Creusot (France)

2007-04-07

346

The forming of coke by catalytic cracking of black mineral oil by catalysts on the base of activated aluminium alloys  

International Nuclear Information System (INIS)

The paper deals with an investigation in coke formation under black mineral oil reactions on oxide catalysts which care based on activated aluminium alloys containing 2-20% of active components of In and Ga. The coke yield is of extreme nature and depends on the content of active components in the catalyst composition. The application of thermogravimetric method shows that the oxidation of coke depositions after black mineral oil cracking proceeds in the same temperature range while after the steam-water treatment of coked catalysts the oxidation of coke deposition proceeds at higher temperatures with different temperature maximums which points to the inhomogeneity of coke depositions. It is shown that the catalyst phase composition changes significantly during the reaction under the effect of reaction mixture. 4 refs., 3 figs.

1995-01-01

347

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

International Nuclear Information System (INIS)

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

2006-01-01

348

Damage induced by creep stress in a short-fiber reinforced aluminium alloy; Schaedigungsentwicklung bei der Kriechbeanspruchung einer kurzfaserverstaerkten Aluminiumlegierung  

Energy Technology Data Exchange (ETDEWEB)

The creep resistance of metallic materials can be decisively enhanced by ceramic fiber reinforcement. The factor determining the lifetime of fiber-reinforced metal matrix composites is the damage to the material induced by in-service creep. The paper examines the tensile creep behaviour of a short-fiber reinforced aluminium alloy and the damaging processes and effects. It was found that fiber fracture is the dominant mechanism. (orig./CB) [Deutsch] Die Kriechbestaendigkeit metallischer Werkstoffe kann durch die Einlagerung keramischer Fasern entscheidend verbessert werden. Bestimmend fuer die Standzeit von faserverstaerkten Metallmatrix-Verbundwerkstoffen ist die im Verlauf der Kriechbeanspruchung eintretende Schaedigung des Werkstoffes. In der vorliegenden Arbeit werden das Zugkriechverhalten einer kurzfaserverstaerkten Aluminiumlegierung und die dabei auftretenden Schaedigungen naeher untersucht. Es konnte gezeigt werden, dass der Bruch von Fasern der dominierende Schaedigungsmechanismus ist. (orig.)

Bidlingmaier, T.; Vogt, D.; Wanner, A.; Arzt, E. [Stuttgart Univ., Inst. fuer Metallkunde (Germany)]|[Max-Planck-Institut fuer Metallforschung (Germany). Inst. fuer Werkstoffwissenschaft, Stuttgart

1997-12-31

349

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

International Nuclear Information System (INIS)

[en] This research thesis reports the study of the oxidation of an aluminium-5 pc magnesium alloy in its liquid state in an oxygen environment, using thermogravimetric analysis and that of magnesium in its solid state. In a first part, the author reports a thermodynamic and bibliographical study on magnesium transformation in its solid state (Mg/O2 and Mg/H2O systems, transformation with dry and humid synthetic air, oxidation inhibitors) and on Al-Mg alloy transformation in presence of oxygen (thermodynamic properties of aluminium-rich Al-Mg alloys, Al-Mg/O2/N2 and Al-Mg/O2/N2/H2O systems). The next parts address the selection of reaction systems for the different cases (oxidation of solid magnesium in oxygen, oxidation of the Al-Mg alloy in oxygen), the modelling of the formation of magnesia from solid magnesium and from the Al-Mg alloy, and the modelling of the liquid Al-Mg A5182 alloy oxidation in oxygen[fr] L'objet de ce travail etait l'etude de l'oxydation d'un alliage aluminium-5 pc magnesium a l'etat liquide sous oxygene, par analyse thermogravimetrique, en s'appuyant sur celle du magnesium a l'etat solide. Dans la plupart des cas, la vitesse absolue d'une reaction est proportionnelle au produit de la reactivite de croissance et de la fonction d'espace caracterisant les dimensions des zones reactionnelles mises en jeu dans le mecanisme de croissance. Nous avons verifie que c'est le cas de la reaction etudiee ici c'est-a-dire la formation de l'oxyde de magnesium. Les mecanismes de formation de la magnesie dependent de la pression partielle d'oxygene fixee dans l'enceinte reactionnelle, l'allure des courbes cinetiques ainsi que les morphologies des oxydes formes etant tres differentes selon la pression d'oxygene. Sous de faibles pressions partielles, la reaction a lieu en phase gaz apres evaporation du magnesium. Dans le cas de l'alliage, un mecanisme de formation de l'oxyde en phase gaz a ete propose. Ce modele permet de rendre compte de l'influence de la pression partielle sur la vitesse de formation par unite de surface d'evaporation de la magnesie. Dans le domaine de fortes pressions d'oxygene et pour le magnesium solide, une modelisation physico-chimique decrivant les mecanismes de croissance de la magnesie et prevoyant l'evolution au cours du temps de la fonction d'espace a ete proposee et validee par confrontation aux resultats experimentaux. Dans le cas de l'alliage, les courbes cinetiques obtenues dans des conditions isothermes et isobares se sont revelees non reproductibles. Une methodologie d'etude, basee sur l'utilisation de la methode des decrochements, a rendu possible la modelisation de la croissance de l'oxyde. En effet, cette methode a permis de determiner l'origine de la non reproductibilite des courbes cinetiques, a savoir l'evolution aleatoire de la fonction d'espace, et d'obtenir les variations de la reactivite de croissance avec la pression d'oxygene. En nous appuyant sur la modelisation proposee pour le magnesium, nous avons propose un modele physico-chimique decrivant les mecanismes de croissance de l'oxyde et rendant compte de l'influence de la pression d'oxygene. (auteur)

1998-01-01

350

Comparative study of the corrosion of a mild steel, a nickel based alloy and an aluminium-coated steel in sulphurising atmosphere (H/sub 2/S). [13 Cr-9 Fe-Ni  

Energy Technology Data Exchange (ETDEWEB)

This work shows that a good protection against sulphidation by H/sub 2/S, near 500 deg.C, can be obtained by aluminium diffusion coating of mild steels. Such coated alloys could replace superalloys in the industry.

Seguin, D. (Inmetal, Universite Simon Bolivar, Caracas (Venezuela)); Colson, J.C.; Lambertin, M. (Faculte des Sciences Mirande, Dijon (France))

1982-01-01

351

Modification of the EN AC-42000 aluminium alloy with use of multicomponent electrolysis of sodium salt  

Directory of Open Access Journals (Sweden)

Full Text Available The present paper discusses results of research concerning the process of continuous modification of the EN AC-42000 (AlSi7Mg) alloy with sodium, based on electrolysis of sodium salts, occurring directly in a melting pot with the liquid alloy. Sodium ions formed as a result of dissociation of the sodium salt and the electrolysis are “transferred” through walls of the retort made from solid electrolyte. Upon contact with the liquid alloy, as a cathode, sodium ions are transformed into atomic state, modifying the alloy. As a measure of the extent of the alloy modification impact strength, elongation A5 and analysis of the microstructure have been obtained, which confirmed the achievement of modification of the alloy under analysis.

J. Pezda

2014-01-01

352

Influences of tool pin profile and tool shoulder diameter on the formation of friction stir processing zone in AA6061 aluminium alloy  

International Nuclear Information System (INIS)

AA6061 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force, etc., and tool pin profile play a major role in deciding the weld quality. In this investigation an attempt has been made to understand the effect of tool pin profile and tool shoulder diameter on FSP zone formation in AA6061 aluminium alloy. Five different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular and square) with three different shoulder diameters have been used to fabricate the joints. The formation of FSP zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the FSP zone formation. From this investigation it is found that the square pin profiled tool with 18 mm shoulder diameter produced mechanically sound and metallurgically defect free welds compared to other tool pin profiles.

2008-01-01

353

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

Energy Technology Data Exchange (ETDEWEB)

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

Emigh, R.A.

1990-07-01

354

Electron-microscopic investigations of irradiated and naturally aged aluminium alloy  

International Nuclear Information System (INIS)

[en] The decay kinetics of solid solution, irradiated and naturally aged alloy of Al-Cu-Mg-Mn system was investigated by the method of transmission electron microscopy. It was shown that in irradiated and natural aged alloy the decay of solid solution proceeds in other mechanism than in non-irradiated one. As a result of irradiation the multilayer dislocation loops of interstitial nature, which serves as discharges for impurity atoms and the centre of metastable phase S' and ?'. It was shown that it promotes to form the more homogeneous and uniform structure of alloy that in one's turn improve the mechanical alloy properties. 11 refs.; 2 figs

1991-01-01

355

Modern aluminium alloys for aeronautical applications. The role of the Al-Li system  

International Nuclear Information System (INIS)

[en] A great effort has been made for some Aluminum Industries since the ''80 to develop new alloys with weight reduction, to use in aeronautic industry. The system Al-Li is a good example of this effort, because it presents a low density and a greater stiffness than usual alloys. In this paper we compare some Al-Li alloys with respect to mechanical properties: fracture toughness and resistance to crack propagation on fatigue case. The results are discussed, as well as the nowadays status and perspectives for the use of these alloys. (author)

1995-01-01

356

Modern aluminium alloys for aeronautical applications. The role of the Al-Li system  

Energy Technology Data Exchange (ETDEWEB)

A great effort has been made for some Aluminum Industries since the ``80 to develop new alloys with weight reduction, to use in aeronautic industry. The system Al-Li is a good example of this effort, because it presents a low density and a greater stiffness than usual alloys. In this paper we compare some Al-Li alloys with respect to mechanical properties: fracture toughness and resistance to crack propagation on fatigue case. The results are discussed, as well as the nowadays status and perspectives for the use of these alloys. (author). 92 refs, 19 figs, 5 tabs.

Godefroid, L.; Bernardes, A.T. [Fed. Univ. of Ouro Preto, Ouro Preto (Brazil); Bastian, F.L. [Fed. Univ. of Rio de Janeiro, Rio de Janeiro (Brazil)

1995-12-31

357

On the structure-property relationship of rapidly solidified high temperature application aluminium alloys  

International Nuclear Information System (INIS)

The phases responsible for high temperature strength and ductility of Al-Fe based alloys, specifically Al-Fe-Mo alloys, have yet to be unambiguously identified. The phases appear to vary slightly under different experimental and processing conditions. This poses some queries concerning the reproducibility of mechanical properties of these alloys. In this paper an attempt is made to address these points and focus on the structure-property relationships of Al-Fe-Mo and Al-Fe-V rapidly solidified powder alloys. 10 refs

1991-01-01

358

Influence of neutron irradiation on intergranular corrosion and corrosion cracking of low-alloyed aluminium alloy SAV-1  

International Nuclear Information System (INIS)

This work represents the data obtained on the influence of neutron irradiation on a tendency to corrosion cracking (CC) and intergranular corrosion (IGC) for low-alloyed SAV-1 aluminum alloy being the basic structural material in the WWR-K research reactor. It was found that irradiation dose plays the main role in change of corrosion properties of low-alloyed aluminum alloy. The tendency towards IGC is maximal for the material with irradiation fluence of 1017 n/cm2, that is caused by secondary precipitates resolution and repeated appearance of zones Guineur-Preston under irradiation. In so doing material transforms to a structural state to be analogous to thermal treatment 'return at ageing'. Increase of irradiation fluence up to 1022 n/cm2 accelerates the ageing process. The growth and coagulation of precipitates of magnesium silicide strengthening phase are observed that increases the alloy tendency to pitting corrosion which strengthens the possibility of corrosion cracking appearance.

2011-01-01

359

SEM-EBSD characterisation of the deformation microstructure in friction stir welded 2024 T351 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

In the present investigation deformation microstructures forming during friction stir welding (FSW) of the aluminium aerospace alloy 2024 T351 have been examined. Electropolished specimen were examined by means of fully automatic electron back-scattered diffraction (EBSD) analysis in a JEOL 840 scanning electron microscope (SEM) equipped with NORDIF EBSD-hardware and Channel 4.2 EBSD-software. The EBSD-technique has proved to be a useful tool for characterisation of the deformation microstructures forming during friction stir welding. Significant local variations in the deformation microstructure are observed in the weld nugget region of the 2024 T351 alloy in the as-welded condition. The grain structure shows characteristics typical of different stages of dynamic recrystallization. In some regions a fully recrystallised microstructure is observed, consisting of very fine 1-2 {mu}m equiaxed grains mainly separated by high angle grain boundaries. Other regions contain grains that are partially recrystallised with a relatively large fraction of subgrains being observed. After high temperature annealing at 500 C for 60 minutes it is evident that abnormal grain growth has occurred in the weld nugget. This microstructure contains a mixture of grains ranging from 4 {mu}m up to about 170 {mu}m. (orig.)

Karlsen, M.; Norum, H. [The Royal Norwegian Air Force (RNoAF) Academy, Trondheim (Norway); Frigaard, Oe. [RNoAF Materiel Command, Analytical Lab., Kjeller (Norway); Hjelen, J. [The Royal Norwegian Air Force (RNoAF) Academy, Trondheim (Norway); Norwegian Univ. of Science and Technology, Dept. of Materials Technology and Electrochemistry, Trondheim (Norway); Grong, Oe. [Norwegian Univ. of Science and Technology, Dept. of Materials Technology and Electrochemistry, Trondheim (Norway)

2003-07-01

360

Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes  

International Nuclear Information System (INIS)

Research highlights: ? Effect of alloying on the corrosion activity of sacrificial Al anodes. ? Sn in solid solution form is a key alloying element for activation of Al anodes. ? Ternary additions that increase Sn solubility decrease the potential of Al alloys. ? Elements bigger than Al expand the Al lattice and allow more Sn to dissolve in Al. ? Large ternary dopants can reduce Sn's solubility in Al if they form compounds with Sn. - Abstract: This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.

2011-01-01

 
 
 
 
361

Stress corrosion cracking of B13, a new high strength aluminium lithium alloy  

International Nuclear Information System (INIS)

The present paper focuses on the study of SCC behaviour of a new Al-Cu-Li alloy. For this purpose, two conventional media - NaCl and NaCl + H2O2 - were used for comparison with commercial alloys 7075 and 8090. This new alloy shows lower susceptibility to SCC than conventional alloys as it does not undergo environmentally-induced embrittlement in NaCl solutions and in 1 M NaCl + 0.3% H2O2 in which the 7075 and 8090 alloys, respectively, undergo environmentally-induced fracture. Solution composition was modified in order to determine the environmental conditions and strain rates under which this new alloy will crack due to a stress corrosion cracking phenomenon. The addition of 0.6 M sulphates to 1 M NaCl + 0.3% H2O2 solution allows the definition of a range of strain rate (between 10-7 and 10-6 s-1) in which this new alloy undergoes stress corrosion cracking

2006-01-01

362

Strain hardening of aluminium alloy 3004 in the deep drawing and ironing processes  

Energy Technology Data Exchange (ETDEWEB)

The evolution of material hardening resulting from the canmaking operations on aluminium beverage cans has been investigated. Tensile tests in cup walls revealed that deep drawing induced softening in the hoop direction and hardening in the meridian direction. This anisotropy is retained in the ironing operation. Changes in strain path on a heavily cold-rolled material probably cause such a complex behaviour. To determine hardening laws for deep drawing, simple shear tests were thus performed because of the strain path similarity. They allowed to determine hardening laws over larger strains than tension could reach and revealed a saturation of stress. Altogether they proved adapted to the understanding of deep drawing. (orig.).

Courbon, J. (Pechiney CRV, 38 Voreppe (France)); Duval, J.L. (Pechiney CRV, 38 Voreppe (France) Lab. des Proprietes Mecaniques et Thermodynamiques des Materiaux (LPMTM-CNRS), Univ. Paris-Nord, 93 Villetaneuse (France))

1993-11-01

363

Fatigue behavior of GMAW welded Aluminium alloy AA7020; Comportamiento a fatiga de uniones soldadas GMAW de la aleacion de aluminio AA 7020  

Energy Technology Data Exchange (ETDEWEB)

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.

Bloem, C. A.; Salvador, M. D.; Amigo, V.; Vicente, A.

2007-07-01

364

Influences of pin profile and rotational speed of the tool on the formation of friction stir processing zone in AA2219 aluminium alloy  

International Nuclear Information System (INIS)

AA2219 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio. Compared to the many fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. The welding parameters and tool pin profile play a major role in deciding the weld quality. In this investigation an attempt has been made to understand the influences of rotational speed and pin profile of the tool on friction stir processed (FSP) zone formation in AA2219 aluminium alloy. Five different tool pin profiles (straight cylindrical, tapered cylindrical, threaded cylindrical, triangular and square) have been used to fabricate the joints at three different tool rotational speeds. The formation of FSP zone has been analysed macroscopically. Tensile properties of the joints have been evaluated and correlated with the FSP zone formation. From this investigation it is found that the square tool pin profile produces mechanically sound and metallurgically defect free welds compared to other tool pin profiles.

2007-06-25

365

Powder forging processing of rapidly solidified aluminium alloy powders; PM arumi gokin no funmatsu tanzo  

Energy Technology Data Exchange (ETDEWEB)

Powder forging processing of rapidly solidified aluminum alloys has realized the excellent material properties attained by rapid solidification process and the high production efficiency of PM parts. This paper describes the preparation of powder forged Al-Si and Al-Fe base alloys using double action forging press and their mechanical properties. Preforms were prepared by metal molding from the rapidly solidified aluminum alloy powders prepared by means of nitrogen gas atomization process. In this process, it is possible to perform two steps of compaction and deformation of preforms in one shot. It was confirmed that the Al-Fe base alloy powder forged by double action forging press exhibits good mechanical properties similar to the extrusion. It was found that the double action forging gives good metallurgical bonding between powders, which is caused by the efficient dispersion of surface oxides, even if the amount of plastic deformation is relatively low. 5 refs., 4 figs., 2 tabs.

Otsuki, M.; Yuri, K.; Kawase, K.; Kono, T. [Mitsubishi Materials Corp., Tokyo (Japan)

1994-08-15

366

Outgassing rate of aluminium alloy vacuum chamber for TRISTAN ultra-high vacuum system  

International Nuclear Information System (INIS)

[en] The TRISTAN Electron Positron Colliding Ring consists of a main ring of 30GeV (e-, e+) with a diameter of approx. 1000 m, and a subordinate ring of 6-8GeV (e-, e+) with a diameter of approx. 100 m for preacceleration and storage. Both rings require a pressure of approx. 10-9 Torr at Beam On and a pressure of approx. 10-10 Torr at Beam Off, respectively. Considering the effect of beam on the vacuum, the chamber is made of aluminum alloy with a high cooling efficiency because the inner walls are exposed to very powerful radiation (3 kW/m (approx. 100 W/cm2)). Generally, aluminum alloy with a high outgassing rate has been thought of as unsuitable for ultra-high vacuum material. A newly developed aluminum alloy produced by special extrusion, however, shows an outgassing rate in the order of 10-14 Torr l/s.cm2 due to 24-hour baking at 1500C. Also, the residual radioactivity in the aluminum new alloy is noticeably reduced, compared with stainless steel. The above-mentioned facts prove that this alloy is excellent as ultra-high vacuum material. As a result of the experiment using the aluminum alloy in all vacuum parts it is confirmed that, contrary to the conventional view, aluminum alloy is most suitable for ultra-high vacuum material and that the TRISTAN Ring in which the alloy is used can be operated with a satisfactory performance. (author)

1985-01-01

367

Light-weight steels based on iron-aluminium - influence of micro alloying elements (B, Ti, Nb) on microstructures, textures and mechanical properties  

Energy Technology Data Exchange (ETDEWEB)

The influence of the micro alloying elements B, Ti and Nb on the recrystallization texture and mechanical properties of iron aluminium light-weight steels, particularly with reference to their improved deep drawing properties was investigated. Depending on the combination of the alloying elements the microstructures of the investigated micro alloyed Fe-6Al steels are influenced by grain refinement. Likewise, variable combinations of micro alloying elements differently affect the texture. Generally, the mechanical properties are improved. However, small amounts of B, Ti and Nb cause superior deep drawing and stretch forming properties of these iron aluminium light-weight steels. The microstructures of various micro alloyed cold rolled Fe-6Al steel sheets were evaluated by optical microscopy, scanning electron microscopy (SEM) inclusively EDAX and X-ray diffraction. Texture measurements were performed using a goniometer with a closed Eulerian cradle and analysed by ODF calculations. Tensile tests were carried out at room temperature and 200 C, respectively. The deep drawing behaviour was determined by performing cupping tests and digitalised strain analysis. (orig.)

Bruex, U.; Frommeyer, G. [Dept. of Materials Technology, Max-Planck-Inst. fuer Eisenforschung GmbH, Duesseldorf (Germany); Jimenez, J. [Centro Nacional de Investigaciones Metalurgicas (C.S.I.C.), Madrid (Spain)

2002-12-01

368

Accelerated artificial ageing regimes of commercial aluminium alloys. II. Al-Cu, Al-Zn-Mg-(Cu), Al-Mg-Si-(Cu)  

Energy Technology Data Exchange (ETDEWEB)

For pt.I see ibid., vol.280, p.83-90, 2000. For Al-Cu, Al-Zn-Mg-(Cu), Al-Mg-Si-(Cu) commercial aluminium alloys effects of temperature and exposure on the phase composition and morphology of hardener precipitates, strength and plasticity were carried out. These results are submitted as TTT (time-temperature-transformation) and TTP (time-temperature-properties) diagrams for ageing. For acceleration of ageing the two-stage ageing regimes with high-temperature stages are used, the characteristics hardener precipitates remaining close to optimum. The examples of the accelerated ageing regimes in industrial conditions for sheets from 1201 alloy (type of 2219), sheets from V95 alloy (type of 7075), forgings from AK6 alloy (system Al-Mg-Si-Cu) are presented. The comparison of the mechanical properties, damage tolerance, corrosion resistance of the semi-products processed by standard and accelerated regimes is given. (orig.)

Ber, L.B. [All-Union Inst. of Light Alloys, Moscow (Russian Federation)

2000-03-15

369

Assessment of corrosion resistance in liquid media of FeAl intermetallic phase based alloys with varied aluminium content  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The paper presented results of corrosion resistance investigations with FeAl intermetallic phase matrix and different aluminium content (38%, 40% and 42%).Design/methodology/approach: In the corrosion research electrolyser, potentiostat „Solartron 1285” and computer with „CorrWare 2” software were used. Results of the research were worked out with „CorrView” software. The potential’s values were determined in relation to normal hydrogen electrode (NEW). The temperature of the solutions was kept on 21ºC level. The recording of potential/density of current - time curve was conducted for 300 s. Sample polarization ranges from potential smaller by 300 mV from normal potential to 0 mV in case of the test in 0.2% HCl solution as well as to 1500 mV in case of 3% H2SO4 solution. Rate of changing the potential amounted 10 mV/min in each case. Observations of the surface state were conducted using scanning electron microscope (JSM – 35) with magnifications from 30 to 1000.Findings: The results were showed that electrochemical corrosion conducted in 0,2% HCl and 3% H2SO4 solution depend on aluminium content. The best electrochemical corrosion resistance in 0.2%HCl have samples of Fe-38Al intermetallic phase based alloy and in 3% H2SO4 have Fe-40Al. It was confirmed by the lowest value of corrosion current density, low value of passive current density, pitting corrosion resistance much higher than in other samples.Research limitations/implications: The results of potentiodynamic research of alloy examined in 0.2% HCl solution are presented in table 1, these for 3% H2SO4 in table 2. Results of the potentiostatic and galvanostatic tests are presented in table 3. In figures 1, 2 the potentiodynamic curve are presented. Table 4 presents results of the surface state after corrosion tests. Figures 3 - 8 present surface state of the samples after corrosion research, which was observed using the scanning electron microscope.Originality/value: Corrosion resistance in liquid media of FeAl intermetallic phase.

J. Cebulski; R. Michalik; S. Lalik

2006-01-01

370

Determination of crystalline texture in aluminium - uranium alloys by neutron diffraction  

International Nuclear Information System (INIS)

Textures of hot-rolled aluminum-uranium alloys and of aluminum were determined by neutron diffraction. Sheets of alloys containing 8.0, 21.5 and 23.7 wt pct U, as well as pure aluminum, were obtained in a stepped rolling process, 15% reduction each step, 75% total reduction. During the rolling the temperature was 6000C. Alloys with low uranium contents are two phase systems in which an intermetallic compound UAl4, orthorhombic, is dispersed in a pure aluminum matrix. The addition of a few percent of Si in such alloys leads to the formation of UAl3, simple cubic, instead of UAl4. The Al -- 23.7 wt pct U alloy was prepared with 2,2 wt pct of Si. The results indicate that the texture of the matrix is more dependent on the uranium concentration than on the texture of the intermetallic phases. An improvement in the technique applied to texture measurements by using a sample fully bathed in the neutron beam is also presented. The method takes advantage of the low neutron absorption of the studied materials as well as of the neglibible variation in the multiple scattering which occurs in a conveniently shaped sample having a weakly developed texture. (Author).

1978-01-01

371

Aluminium production  

International Nuclear Information System (INIS)

[en] Aluminium is the most important non-ferrous metal by quantity. Aluminium is produced by electrolysis of aluminium oxide (also known as alumina). Alumina is produced by refining bauxite. The quantity of primary and secondary aluminium production in ECE-countries between 1992 and 1998 is shown. The European aluminium industry employs approximately 200 000 employees. The annual aluminium production in the European Union was 3.58 million tonnes in 1994, of which 44 % was secondary aluminium. In 1996 3.96 million tonnes of aluminium were produced in the EU, of which 44 % was secondary aluminium. (author)

372

The effect of Mg precipitation on the mechanical properties of 5xxx aluminum alloys  

International Nuclear Information System (INIS)

Industrially produced continuous cast (CC) aluminum alloys AA5182 and AA5052 were heat-treated at a low temperature of 182 deg. C for different times (30 and 100 h). Samples from the hot band (hot band in continuous cast process is produced through hot rolling of the materials at relatively high temperatures, usually from 490 to 310 deg. C) and the heat-treated materials were prepared for microstructure examination, chemical composition analysis, electrical resistivity testing and tensile testing. Particle structures of CC5182 alloy show precipitation along the grain boundaries after this low temperature heat-treatment. The particles were identified by SEM analysis to be Mg precipitates (Mg2Al3). Due to the Mg precipitation, electrical resistivity, elongation and ultimate tensile strength decreased. As the interaction between Mg solute atoms in solid solution and mobile dislocations decreases due to precipitation, the magnitude of the stress drop in the serrations decreases and the critical strain for the onset of serrated yielding increases in CC5182 alloy. These phenomena do not occur in CC5052 alloy since precipitation either does not occur or is much weaker in this alloy. An inverse serrated yielding behavior, which is characterized by an increase in the critical strain for the onset of serrated yielding with a decrease in strain rate, occurs in CC5182 alloy but not in CC5052 alloy. This inverse behavior is believed to be related to precipitation during tensile deformation in CC5182 alloy.

2005-02-15

373

The effect of Mg precipitation on the mechanical properties of 5xxx aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

Industrially produced continuous cast (CC) aluminum alloys AA5182 and AA5052 were heat-treated at a low temperature of 182 deg. C for different times (30 and 100 h). Samples from the hot band (hot band in continuous cast process is produced through hot rolling of the materials at relatively high temperatures, usually from 490 to 310 deg. C) and the heat-treated materials were prepared for microstructure examination, chemical composition analysis, electrical resistivity testing and tensile testing. Particle structures of CC5182 alloy show precipitation along the grain boundaries after this low temperature heat-treatment. The particles were identified by SEM analysis to be Mg precipitates (Mg{sub 2}Al{sub 3}). Due to the Mg precipitation, electrical resistivity, elongation and ultimate tensile strength decreased. As the interaction between Mg solute atoms in solid solution and mobile dislocations decreases due to precipitation, the magnitude of the stress drop in the serrations decreases and the critical strain for the onset of serrated yielding increases in CC5182 alloy. These phenomena do not occur in CC5052 alloy since precipitation either does not occur or is much weaker in this alloy. An inverse serrated yielding behavior, which is characterized by an increase in the critical strain for the onset of serrated yielding with a decrease in strain rate, occurs in CC5182 alloy but not in CC5052 alloy. This inverse behavior is believed to be related to precipitation during tensile deformation in CC5182 alloy.

Wen Wei [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506-0046 (United States)]. E-mail: wwen0@engr.uky.edu; Zhao Yumin [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506-0046 (United States); Morris, J.G. [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506-0046 (United States)

2005-02-15

374

Inhibition of Corrosion of Aluminium and its Alloys by Extracts of Green Inhibitors  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Aluminium is the most widely used non ferrous metal. It is very needful to prevent this metal from corrosion .Corrosion inhibitors are one of the widely used methods to control corrosion. The purpose of this paper is to make people aware of organic corrosion inhibitors. Organic inhibitors are mainly present in natural products. It has been found that plant extracts and natural products show inhibition efficiency up to 98%. They are also non-toxic, eco-friendly, very cheap (more) er. In the present work, natural products are used at various conditions and their inhibition efficiency is calculated by different methods; they obey various adsorption isotherms; the protective films formed by the inhibitors are analyzed by techniques such as electrochemical methods, FTIR, HPLC-RP, SEM, EDS.

Sangeetha, M.; Rajendran, S.; Sathiyabama, J.; Krishnavenic, A.

2013-01-01

375

Role of aluminium concentration on the structure behaviour of Cu-Al alloys  

International Nuclear Information System (INIS)

Effect of Al(5, 10, 15 and 20)% on the structure behaviour of Cu-Al alloys was investigated by both microhardness measurements and optical microscopic investigations. Pure Cu was used for comparison. The analysis of the hardness-temperature curve shows a type of dependence which obeys an empirical exponential law, but consists of several distinguishable regions. For Cu 20% Al, one region is observed, and two regions for pure Cu, while for alloys of 5 and 10% Al concentration three regions were observed. The activation energy varies between 0.03 and 0.9 ev. for these regions, depending on the Al-concentration as well as the annealing temperature. The recrystallization temperature was found to increase with increasing Al-concentration. It was also observed that Cu-20% Al alloy is very hard and brittle owing to the formation of ?2 phase, and also to phase separation as being detected from optical microscopic investigations. (author). 22 refs, 3 figs.

1988-01-01

376

Development and Strengthening of 2219 Aluminium Alloy by Mechanical Working and Heat Treatment  

Directory of Open Access Journals (Sweden)

Full Text Available The wrought aluminum alloy 2219 was developed using an induction furnace followed by forging and hot rolling for the improvement of properties. Then the alloy was solution treated at 535°C for 48 min followed by water quenched and then aged at 210, 230 and 240°C for different time period. The maximum tensile strength of 411 MPa and hardness of 113.7 HV were achieved at 210°C after 4 h aging. The tensile strength of 368.12 MPa and hardness of 95.32 HV were obtained at 240°C after only 1.5 h aging time. The strength and hardness values of aged alloy specimens obtained in this work were reasonably higher (strength 51% and hardness 81%) than the specimens which were solution treated and quenched. Microstructures of the aged specimens also provided an evidence of dispersion of second phase precipitates particles in the single phase matrix.

M. Rafi Raza; Faiz Ahmad; N. Ikram; R. Ahmad; A. Salam

2011-01-01

377

Aging response of aluminium alloy 2024/silicon carbide particles (SiCp) composites  

International Nuclear Information System (INIS)

[en] The aging behaviour of AA2024/0, 8, 14, 19, and 24 vol.% SiCp composites was studied using the hardness Rockwell B and X-ray diffraction techniques. The composites were manufactured by stir-casting in the semi-solid state of the alloy AA2024 (compocasting). Aging of the composites and unreinforced alloy took place at 177 deg,C for a period of 2-200 h. Precipitation phases present were Al2CuMg for the unreinforced alloy 2024, and CuAl2, Mg2Si for the composites. Peak hardness increased as the SiCp volume fraction increased and appeared almost at the same time after about 14 h aging in all the materials. The hardness reduction rate in the overaged condition decreased with increasing SiCp content

378

Comparison of modification with strontium and the refining with antimony in A 356 aluminium alloys; Comparacao entre a modificacao com estroncio e o refino com antimonio em ligas de aluminio a 356  

Energy Technology Data Exchange (ETDEWEB)

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) 26 refs., 13 figs., 2 tabs.

Fuoco, Ricardo; Correa, Edison Roberto; Correa, Alzira V.O.; Bocalini Junior, Mario

1992-12-31

379

Two-phase modelling of hot tearing in aluminium alloys using a semi-coupled method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hot tearing is one of the most severe defects observed in castings, e.g. in billets or sheet ingots of aluminum alloys produced by DC casting. It is due to both tensile strains and a lack of interdendritic feeding in the mushy zone. In order to predict this phenomenon at the scale of an entire casti...

Mathier, Vincent

380

High-aluminium zinc alloy (ZnAl27Cu2) modified with titanium and boron  

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Full Text Available The paper presents the results of investigations concerning the influence of the titanium-boron modifier quantity on the structure and mechanical properties of ZnAl27Cu2 alloy. The modification has been performed with the use of AlTi5B1 master alloy, thus introducing into the molten alloy 0.015%Ti and 0.003%B; 0.025%Ti and 0.005%B; 0.035%Ti and 0.007%B and eventually 0.045%Ti and 0.009%B. Samples for examination have been cast in sand moulds. The optimum mechanical properties Rm=440MPa and A5=8% have been achieved by introducing 0.035% Ti and 0.007% B into the alloy. It has been found that morphological changes of the primary crystals of ? solid solution take place due to the modification. The dendrites with widely outspread arms take the shape of rounded, globular crystals. The size of ? phase crystals decreases, but to the rather small degree, proportionally to the quantity of added modifier.

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

2009-01-01

 
 
 
 
381

Effect of sealed anodic film on fatigue performance of 2214-T6 aluminium alloy  

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The aim of present study is to investigate the influence of anodic film, grown by sulfuric acid anodizing and sealed in nickel-acetate solution, on fatigue strength of aluminum alloy 2214-T6 by conducting axial fatigue tests at stress ratio 'R' of 0.1 and ? 1. The influence of sealed anodic film is ...

Shahzad, Majid; Chaussumier, Michel; Chieragatti, Rémy; Mabru, Catherine; Rezaï-Aria, Farhad

382

Study of corrosion of aluminium alloys of nuclear purity in ordinary water, ?art one  

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Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VIN?A Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Resear...

Peši? Milan P.; Maksin Tatjana N.; Jordanov Gabrijela; Dobrijevi? Rajko; I?akovi? Zoja E.

383

The application of EBSD to the study of substructural development in a cold rolled single-phase aluminium alloy  

International Nuclear Information System (INIS)

Scanning electron microscopy and high resolution electron backscatter diffraction (EBSD) have been used to study substructural development during cold rolling of a single-phase Al-0.1 Mg alloy, the use of EBSD enabling more detailed quantitative measurements to be made than are possible with the transmission electron microscope (TEM). At low strains, bands of elongated cells, aligned at approximately 35 deg. to rolling direction are formed. As the applied strain was increased, intersecting thinner and more widely spaced bands form within many grains, flow becomes localised within these new bands and they develop into microshear bands, which shear the original elongated cell structures. The changes in the scale of the microstructural features, the development of misorientations of the various types of low angle boundary and the alignment of the features to the rolling plane have been measured as a function of strain. The results are compared with previous TEM investigations of deformed aluminium, and a qualitative model of the microstructural evolution is proposed.

2003-02-25

384

Effects of the temperature of warm rolling on the superplastic behaviour of AA5083 aluminium base alloy  

Energy Technology Data Exchange (ETDEWEB)

The effects of the temperature of preliminary thermomechanical treatment (TMT) on the superplastic forming parameters of commercial grade aluminium base alloy AA5083 have been studied. The TMT performed included multiple-pass warm rolling followed by cold rolling with a reduction ratio per pass approximately equal to two. The temperature of the warm rolling, T{sub WR}, was varied between 250 and 500 C. The dependence of superplastic elongation on the temperature of warm rolling during TMT was investigated by tensile testing dog-bone samples at 350 and 500 C. The research shows that material warm rolled at temperatures close to 350 C yields maximum values of elongation to fracture. Refinement and change of distribution of intermetallic particles occur in the process of warm rolling AA5083. Pycnometric measurements show that the porosity of the material after a full cycle of TMT, encompassing warm and cold rolling, increases monotonically with the rolling temperature. SEM/EDS observations additionally show that warm rolling at lower temperatures is accompanied by the formation of Si- and Mg-rich segregations at the interfaces between the intermetallic particles and matrix. Both these phenomena lead to a significant decrease in the SPF properties of AA5083. (orig.)

Pimenoff, J.; Romu, J.; Haenninen, H. [Helsinki Univ. of Technology (Finland). Lab. of Engineering Materials; Yagodzinskyy, Y. [National Academy of Science of Ukraine, Kiev (Ukraine). Inst. for Metal Physics

2001-07-01

385

A numerical study on the influence of the Portevin Le Chatelier effect on necking in an aluminium alloy  

Science.gov (United States)

The constitutive relation proposed by McCormick (1988 Acta Metall. 36 3061-7) for materials exhibiting negative steady-state strain-rate sensitivity and the Portevin-Le Chatelier (PLC) effect is incorporated into an elastic-viscoplastic model for metals with plastic anisotropy. The constitutive model is implemented in LS-DYNA for corotational shell elements. Plastic anisotropy is taken into account by use of the yield criterion Yld2000/Yld2003 proposed by Barlat et al (2003 J. Plast. 19 1297-319) and Aretz (2004 Modelling Simul. Mater. Sci. Eng. 12 491-509). The parameters of the constitutive equations are determined for a rolled aluminium alloy (AA5083-H116) exhibiting negative steady-state strain-rate sensitivity and serrated yielding. The parameter identification is based on existing experimental data. A numerical investigation is conducted to determine the influence of the PLC effect on the onset of necking in uniaxial and biaxial tension for different overall strain rates. The numerical simulations show that the PLC effect leads to significant reductions in the strain to necking for both uniaxial and biaxial stress states. Increased surface roughness with plastic deformation is predicted for strain rates giving serrated yielding in uniaxial tension. It is likely that this is an important reason for the reduced critical strains. The characteristics of the deformation bands (orientation, width, velocity and strain rate) are also studied.

Hopperstad, O. S.; Børvik, T.; Berstad, T.; Lademo, O.-G.; Benallal, A.

2007-10-01

386

The analysis of initiation and growth of cracks in diffusion aluminium coatings on ZS6U alloy in conditions of thermal fatigue  

International Nuclear Information System (INIS)

[en] The paper deals with the analysis of thermal fatigue of nickel based ZS6U super alloy with 'Si-Ai' and 'Cr-Al' aluminium diffusion coatings. The processes of initiation and growth of cracks in diffusion coating in the conditions of cyclic changing temperature (500 oC - 950 oC) and simultaneous Fo constant axial force loading have been analysed. The results of numerical calculations of stress distribution in the specimen with aluminium coatings have been presented. They enabled to elaborate the models of mechanical behaviour of coatings, which in turn helped to explain different character of cracks in the assumed experimental conditions. Thermal fatigue tests performed at lower static component of Fo loading spectrum proved that aluminium coatings obtained in course of 'Si-Al' process show the highest lifetime respectively of their thickness. Moreover, the lifetime of 'Si-Al' aluminium coatings decreases together with the increase of static component of load fatigue spectrum unlike in case of 'Cr-Al' coatings. (author)

2002-01-01

387

Corrosion behaviour of aluminium-lithium alloys under seawater and marine environmental conditions. Korrosionsverhalten von Aluminium-Lithium-Werkstoffen in Meeresklima und bei Meerwasserbeanspruchung  

Energy Technology Data Exchange (ETDEWEB)

The materials investigated in this study were the AlLiMgCu alloy 8090, in different artificial ageing conditions, and the AlCuMg alloy 2024 T351 as extruded profiles. The electrochemistry of these alloys was investigated in aerated artificial seawater in the laboratory. Their longterm corrosion behaviour under natural marine conditions was studied in the spray water zone as well as in the alternate and permanent immersion zones at the corrosion test rack on Helgoland, and by atmospheric exposure on the island of Sylt. The free corrosion potential and the critical electrochemical threshold potential for corrosion of the lithium-free alloy 2024 T351 is at more positive, nobler values in comparison to those of the various heat treatment states of the alloy 8090. However, because of the susceptibility of the 2024 T351 alloy to deep exfoliation corrosion depth of corrosion of the AlLi alloy 8090 was less in the longterm marine exposure tests. (orig.).

Holbein, R.; Dembeck, A. (Dornier Luftfahrt GmbH, Friedrichshafen (Germany, F.R.))

1990-11-01

388

Calorimetric study of enthalpies of mixing in liquid (aluminium-gallium-yttrium) alloys  

Energy Technology Data Exchange (ETDEWEB)

The partial yttrium ({delta}{sub mix}H-bar {sub Y}) and the integral ({delta}{sub mix}H) enthalpies of mixing of liquid ternary Al-Ga-Y alloys have been determined by high-temperature mixing calorimetry at T=1750K. The measurements have been performed along five sections with constant ratios of Al and Ga in a range of 0.0alloys is discussed.

Kanibolotsky, Dmitry S. [Biophysical Department, Academician Peter Bogach Institute, Glushkova Avenue 2, Building 12, Kiev UA-03022 (Ukraine) and Chemical Department, Kiev National Taras Shevchenko University, Vladimirskaya Street 64, Kiev UA-01033 (Ukraine)]. E-mail: kanibolotsky@univ.kiev.ua; Bieloborodova, Olena A. [Chemical Department, Kiev National Taras Shevchenko University, Vladimirskaya Street 64, Kiev UA-01033 (Ukraine); Lisnyak, Vladyslav V. [Chemical Department, Kiev National Taras Shevchenko University, Vladimirskaya Street 64, Kiev UA-01033 (Ukraine)]. E-mail: lisnyak@chem.univ.kiev.ua

2006-09-15

389

Continuous sodium modification of nearly-eutectic aluminium alloys. Part II. Experimental studiem  

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Full Text Available One of the possible means of continuous sodium modification of nearly-eutectic alloys may be continuous electrolysis of sodium compounds (salts), taking place directly in metal bath (in the crucible). For this process it is necessary to use a solid electrolyte conducting sodium ions. Under the effect of the applied direct current voltage, sodium salt placed in a retort made from the solid electrolyte undergoes dissociation, and next - electrolysis. The retort is immersed in liquid metal. The anode is sodium salt, at that temperature occurring in liquid state, connected to the direct current source through, e.g. a graphite electrode, while cathode is the liquid metal. Sodium ions formed during the sodium salt dissociation and electrolysis are transported through the wall of the solid electrolyte (the material of the retort) and in contact with liquid alloy acting as a cathode, they are passing into atomic state, modifying the metal bath.

Bia?obrzeski A.; Saja K.; Le?niewski W.

2007-01-01

390

Corrosion behaviour of ion implanted aluminium alloy in 0.1 M NaCl electrolyte  

Energy Technology Data Exchange (ETDEWEB)

Aluminum and its alloys are widely used in industry because of their light weight, high strength and good corrosion resistance which is due to the formation of a protective oxide layer. However, under saline conditions such as those encountered in marine environments, this group of metals are vulnerable to localised degradation in the form of pitting corrosion. This type of corrosion involves the adsorption of an anion, such as chlorine, at the oxide solution interface. Ion implantation of metal ions has been shown to improve the corrosion resistance of a variety of materials. This effect occurs : when the implanted species reduces anion adsorption thereby decreasing the corrosion rate. In this paper we report on the pitting behavior of Ti implanted 2011 Al alloy in dilute sodium chloride solution. The Ti implanted surfaces exhibited an increased pitting potential and a reduced oxygen uptake. 5 refs., 3 figs.

Chu, J.W.; Evans, P.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

1993-12-31

391

Effect of microstructure on the hot deformation characteristics of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

On the basis of results of hot tensile tests made in the range of temperature 623-873 K and strain rate range of 10{sup -4}-10{sup -2}s{sup -1} on Al99.99, AlMgMn and AlMgSi materials, stress exponent of n=4.2, 4.8, and 4.8 and activation energies of 120, 140 and 165 kJ/mol were obtained, respectively. In one case for an AlFeSi alloy n=7 and Q=220 kJ/mol was found. The strain to fracture increases slightly with strain rate and temperature in the alloys. The results are explained by the effect of different intermetallic particles. (orig.)

Kovacs-Csetenyi, E. [R and D Centre Ltd., Budapest (Hungary); Chinh, N.Q. [Eoetvoes Univ., Budapest (Hungary). Inst. for Gen. Phys.; Kovacs, I. [Eoetvoes Univ., Budapest (Hungary). Inst. for Gen. Phys.

1996-12-01

392

Study of corrosion of aluminium alloys of nuclear purity in ordinary water, ?art one  

Directory of Open Access Journals (Sweden)

Full Text Available Effects of corrosion of aluminum alloys of nuclear purity in ordinary water of the spent fuel storage pool of the RA research reactor at VIN?A Institute of Nuclear Sciences has been examined in the frame work of the International Atomic Energy Agency Coordinated Research Project "Corrosion of Research Reactor Aluminum-Clad Spent Fuel in Water" since 2002. The study presented in this paper comprises activities on determination and monitoring of chemical parameters and radio activity of water and sludge in the RA spent fuel storage pool and results of the initial study of corrosion effects obtained by visual examinations of surfaces of various coupons made of aluminum alloys of nuclear purity of the test racks exposed to the pool water for a period from six months to six years.

Peši? Milan P.; Maksin Tatjana N.; Jordanov Gabrijela; Dobrijevi? Rajko; I?akovi? Zoja E.

2004-01-01

393

Corrosion behaviour of ion implanted aluminium alloy in 0.1 M NaCl electrolyte  

International Nuclear Information System (INIS)

Aluminum and its alloys are widely used in industry because of their light weight, high strength and good corrosion resistance which is due to the formation of a protective oxide layer. However, under saline conditions such as those encountered in marine environments, this group of metals are vulnerable to localised degradation in the form of pitting corrosion. This type of corrosion involves the adsorption of an anion, such as chlorine, at the oxide solution interface. Ion implantation of metal ions has been shown to improve the corrosion resistance of a variety of materials. This effect occurs : when the implanted species reduces anion adsorption thereby decreasing the corrosion rate. In this paper we report on the pitting behavior of Ti implanted 2011 Al alloy in dilute sodium chloride solution. The Ti implanted surfaces exhibited an increased pitting potential and a reduced oxygen uptake. 5 refs., 3 figs.

1993-01-01