WorldWideScience
 
 
1

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

International Nuclear Information System (INIS)

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

2010-03-08

2

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

International Nuclear Information System (INIS)

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

1980-01-01

3

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

Science.gov (United States)

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

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

2013-09-01

4

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

Directory of Open Access Journals (Sweden)

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

Tiago Valdameri Capelari

2009-09-01

5

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

Scientific Electronic Library Online (English)

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

Tiago Valdameri, Capelari; José Antônio Esmerio, Mazzaferro.

6

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-15

7

Experimental Observations of Quasi-Static-Dynamic Formability in Biaxially Strained AA5052-O  

Science.gov (United States)

To establish the efficacy of electromagnetically assisted sheet metal stamping (EMAS), a series of combined hydraulic bulging and electromagnetic forming (EMF) experiments are presented to evaluate the biaxial quasi-static-dynamic formability of an aluminum alloy (AA5052-O) sheet material. Data on formability are plotted in principal strain space and show an enhanced biaxial formability beyond the corresponding experimental results from conventional forming limit diagram. The plastic strains produced by the combined process are a little larger than or at least similar with those obtained in the fully dynamic EMF process. In addition, the biaxial forming limits of aluminum sheets undergoing both very low and high quasi-static prestraining are almost similar in quasi-static-dynamic bulging process. Limit formability seems to depend largely on the high-velocity loading condition as dictated by EMF. It appears that in quasi-static-dynamic forming, quasi-static loading is not of primary importance to the material's formability. Based on these observations, one may be able to develop forming operations that take advantage of this formability improvement of quasi-static-dynamic deformation. Also, this could enable the use of a quasi-static preform fairly close to the quasi-static material limits for the design of an EMAS process.

Liu, Dahai; Yu, Haiping; Li, Chunfeng

2011-03-01

8

Hydrogen generation from aluminium corrosion in reactor containment spray solutions  

International Nuclear Information System (INIS)

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

1982-10-03

9

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 "1"4C 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

10

Effect of hydrogen on aluminium and aluminium alloys: A review  

DEFF Research Database (Denmark)

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

Ambat, Rajan; Dwarakadasa, E.S.

1996-01-01

11

Alloys of uranium and aluminium with low aluminium content  

International Nuclear Information System (INIS)

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

1955-08-01

12

Aluminium effect on titanium alloys fracture mode  

International Nuclear Information System (INIS)

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

1984-01-01

13

Oxidation of aluminium-cerium alloys  

International Nuclear Information System (INIS)

By methods of thermo-and mass gravimetry is shown that oxidation kinetics of aluminium-cerium alloys depends on the phase composition and temperature. Liquid alloys oxidation is subjected to parabolic law. The oxidation rate constant is of the order 10-3kg(m2 x s). Refs. 3, figs. 5

1995-01-01

14

Characterisation of a novel lead-aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Alloying lead with aluminium for use in lead/acid batteries is desirable because of aluminium`s light weight, high conductivity and good mechanical properties. A study was conducted to synthesize a typical Pb-4Al alloy by mechanical alloying and then to examine its mechanical and electrochemical properties. The lead-aluminium system is a typical immiscible system, with little solubility of aluminium in molten lead. Efforts were made to increase the aluminium content in lead by the mechanical alloying (MA) method and by introducing tin as a third alloying element to produce a Pb-Al-Sn ternary alloy. In order to study the aluminium effect and make a comparison between the MA method and the conventional casting method, a ternary alloy with a similar high aluminium content to Pb-Al-Sn system was prepared by casting. The potential application of a new lead/acid grid alloy was discussed. 13 refs., 6 figs.

Zhong, S.; Wang, J.; Liu, H.K.; Dou, S.X. [Wollongong Univ., NSW (Australia); Skyllas-Kazacos, M. [New South Wales Univ., Sydney, NSW (Australia)

1997-12-31

15

Steam generated conversion coating on aluminium alloys  

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Jellesen, Morten Stendahl

16

Improved aluminium alloy for engine applications  

Energy Technology Data Exchange (ETDEWEB)

Comalco Research has examined the wear mechanisms occurring in aluminium alloys under a variety of conditions and various alloy structures. The knowledge gained from these investigations has been used to develop a new high strength wear resistant alloy designated 3HA. Although the properties of the alloy make it suitable for a variety of wearing applications, it is especially suited to the production of unlinered aluminium engine blocks. To fully establish the suitability of the alloy for this application, dynamometer tests of both two-stroke and four-stroke engines have been carried out. Initial results of these tests have been extremely encouraging, with a set of 3HA four-stroke cylinder liners lasting over four times the prescribed duration of the severe cold scuff test.

Legge, R.A.; Smith, D.M.; Henkel, G.

1986-01-01

17

Prospects in alloying of aluminium alloys with scandium  

International Nuclear Information System (INIS)

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

1982-12-01

18

Aluminium effect on titanium alloys fracture mode  

Energy Technology Data Exchange (ETDEWEB)

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

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

1984-01-01

19

Potential for improved mechanical properties in cast aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1999-01-01

20

Combining aluminium alloys with steel by welding  

International Nuclear Information System (INIS)

The problems arising in combining aluminium alloys with steel because of the different material properties are reported in a summarizing paper. Pressure welding methods and fusion welding methods with intermediate layers, their effectiveness with respect to the prevention of intermetallic compounds being formed, properties of the intermetallic phases and welding parameters investigated until now are discussed. (IHOE)

1980-01-01

 
 
 
 
21

Analysis of uranium and some uranium alloys. Aluminium spectrophotometric determination  

International Nuclear Information System (INIS)

Aluminium determination in uranium and U-Al-Fe alloy with 700 ppm of aluminium and 300 ppm of iron by dissolution in nitric-sulfuric acid and extraction of aluminium oxinate and spectrophotometry at 390 nm. The method is applicable for aluminium content between 200 to 5000 ppm

22

Softening Behaviour of Selected Commercially Pure Aluminium Model Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2012-01-01

23

Melt spun aluminium alloys for moulding optics  

Science.gov (United States)

Melt spinning is a rapid quenching process that makes it possible to create materials with a very fine microstructure. Due to this very fine microstructure the melt spinning process is an enabler for diamond turning optics and moulds without the need of post-polishing. Using diamond turning of melt spun aluminium one can achieve diamond-like carbon (DLC) and chromium nitride (CrN). These coatings make the aluminium alloy suitable for moulding mass production of small as well as larger optics, such as spectacle lenses.

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

2013-09-01

24

TEM microstructure investigations of aluminium alloys used for laser alloying  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: In this paper there are presented results of Transmission Electron Microscope investigation concerning the structure of the AlSi7Cu4 cast aluminium alloy using for alloying and remelting with the high power diode laser (HPDL). There are also presented the results of the thermo-derivative analysis performed using the UMSA (Universal Metallurgical Simulator and Analyser) device, allowing to determine the specific points of the solidifying alloy, what is helpful for phase determination ...

2012-01-01

25

Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys  

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Jellesen, Morten Stendahl

2013-01-01

26

Neutron radiography of aluminium alloy corrosion damage  

International Nuclear Information System (INIS)

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

1988-01-01

27

Aluminium and its alloys welding  

International Nuclear Information System (INIS)

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

2004-01-01

28

Aluminium alloys containing iron and nickel  

International Nuclear Information System (INIS)

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

1958-01-01

29

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 technological property and depends on many parameters. However, many aspects of this subject are still not fully understood. The motivation of the research presented in this doctoral thesis was, there...

Di Sabatino, Marisa

2007-01-01

30

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 technological property and depends on many parameters. However, many aspects of this subject are still not fully understood. The motivation of the research presented in this doctoral thesis was, there...

Di Sabatino, Marisa

2005-01-01

31

FSW characterization of 6082 aluminium alloys sheets  

Directory of Open Access Journals (Sweden)

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

K. Mroczka

2009-12-01

32

Solidification microstructures of aluminium-uranium alloys  

International Nuclear Information System (INIS)

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

1976-09-01

33

Cold Spray Deposition of Titanium onto Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 Pl...

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

2010-01-01

34

Heat resisting steel properties at complex nickel and aluminium alloying  

International Nuclear Information System (INIS)

Efficiency of effect of combined nickel and aluminium alloying up to 8% for each on the properties of manganese steel of austenitic class [6] are investigated. It is ascertained that complex aluminium and nickel alloying by 6% of each one leads to steel precipitation hardening with the maximum strength increase by 20% at 750 deg C ageing temperature

1989-01-01

35

TEM microstructure investigations of aluminium alloys used for laser alloying  

Directory of Open Access Journals (Sweden)

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

K. Labisz

2012-12-01

36

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Birch, M.; Cowell, A.

1987-01-01

37

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2005-01-01

38

Manganese-aluminium complex alloy for steel reduction  

International Nuclear Information System (INIS)

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

1983-01-01

39

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

Scientific Electronic Library Online (English)

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

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

40

Effect of filtration on reoxidation proceses in aluminium alloys  

Directory of Open Access Journals (Sweden)

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

D. Bolibruchova

2010-01-01

 
 
 
 
41

Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2013-01-01

42

Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate  

Directory of Open Access Journals (Sweden)

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

B. Bobic

2010-03-01

43

Examples of liquid metal embrittlement in industrial aluminium alloys  

International Nuclear Information System (INIS)

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

2002-09-01

44

Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins  

Directory of Open Access Journals (Sweden)

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

Ivan Michalec

2013-01-01

45

A study on the recycling of aluminium alloy 7075 scrap  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-01

46

Hydrogen and porosity in aluminium-silicon and aluminium-magnesium alloys. Pt. 1. Aluminium-silicon alloys. Wasserstoff und Porositaet in Aluminium-Silicium- und Aluminium-Magnesium-Legierungen. T. 1. Aluminium-Silicium-Legierungen  

Energy Technology Data Exchange (ETDEWEB)

Gas porosity in aluminium castings is frequently encountered as a casting defect which is responsible for low material properties. By applying a new measuring device for direct hydrogen determination in aluminium melts the connection between hydrogen content and porosity was studied for Al-Si- and Al-Mg-casting alloys under consideration of melt treatment and solidification conditions. The influence of hydrogen content and alloy composition on porosity was evaluated in the system aluminium-silicon. The results indicate that the tendency for pore formation is greatest with alloy AlSi7Mg. Lower solidification rates and modification with strontium lead to higher gas porosity. Typical pore shapes and the distribution of pores in the casting as shown by metallographic studies are described. (orig.).

Chen Xiaoguang; Engler, S. (Technische Hochschule Aachen (Germany). Giesserei-Institut)

1991-10-01

47

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 processing. Iron and silicon are accumulative elements, meaning that they can never be completely eliminated once introduced into the aluminium. Some alloys have very narrow compositional windows, they ha...

Slagsvold, Marius

2011-01-01

48

Computer modelling of age hardening for cast aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Age hardening, or precipitation hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. Although various age hardening models have been developed for aluminium alloys, from the large volume of literature reviewed, it appears that the bulk of the research has been concentrated on wrought aluminium alloys, only a few of the established precipitation models have been applied to the casting aluminium alloys. In the present work, there are two modelling methods that have been developed and applied to the casting aluminium alloys A356 and A357. One is based on the Shercliff-Ashby methodology to produce a process model, by which we mean a mathematical relationship between process variables (alloy composition, ageing temperature and time) and material properties (yield strength or hardness) through microstructure evolution (precipitate radius, volume fraction). The other method is based on the Kampmann and Wagner Numerical (KWN) model which deals with concomitant nucleation, growth and coarsening and is thus capable of predicting the full evolution of the particle size distribution and then a strength model is used to evaluate the resulting change in hardness or yield strength at room temperature by taking into account contributions from lattice resistance, solid solution hardening and precipitation hardening.

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

2009-08-15

49

Computer modelling of age hardening for cast aluminium alloys  

Science.gov (United States)

Age hardening, or precipitation hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. Although various age hardening models have been developed for aluminium alloys, from the large volume of literature reviewed, it appears that the bulk of the research has been concentrated on wrought aluminium alloys, only a few of the established precipitation models have been applied to the casting aluminium alloys. In the present work, there are two modelling methods that have been developed and applied to the casting aluminium alloys A356 and A357. One is based on the Shercliff-Ashby methodology to produce a process model, by which we mean a mathematical relationship between process variables (alloy composition, ageing temperature and time) and material properties (yield strength or hardness) through microstructure evolution (precipitate radius, volume fraction). The other method is based on the Kampmann and Wagner Numerical (KWN) model which deals with concomitant nucleation, growth and coarsening and is thus capable of predicting the full evolution of the particle size distribution and then a strength model is used to evaluate the resulting change in hardness or yield strength at room temperature by taking into account contributions from lattice resistance, solid solution hardening and precipitation hardening.

Wu, Linda; Ferguson, W. George

2009-08-01

50

Effect of hydrogen plasma on aluminium-lithium alloys  

International Nuclear Information System (INIS)

Effect of heat flux (with power density up to 1 kWt/cm2) as well as fast particles flux (about 1019 s-1 ions and neutral hydrogen) on aluminium-lithium alloys is experimentally studied. Principal possibility of using the studied alloys as plasma chamber cathod materials and divertor plates of thermonuclear reactor with magnet holding of plasma is shown

1992-01-01

51

Method of preparing aluminium-uranium alloy detection foils  

International Nuclear Information System (INIS)

The aluminium-uranium alloy is prepared by uranium alloying of high-purity molten aluminium, which produces the intermetallic UAl_3 phase. The alloy is poured at a temperature of 800 degC into a horizontal mould to preclude gravitational separation of uranium during solidification. In order to achieve a homogeneous distribution of UAl_3 the ingot is annealed at a temperature of 550 degC for three hours and is then quenched in water. The foil is first hot rolled at a temperature between 450 and 480 degC and then cold rolled to a thickness of 0.05 mm. During the rolling process a 50% deformation takes place after which intermediate annealing follows at a temperature of 480 degC for 20 mins. The achievement of the new method is an easier production of foils than with the use of pure uranium and the high corrosion resistance of the uranium-aluminium alloy foil. (Ha)

1981-11-17

52

Corrosion electrochemical behaviour of aluminium alloys with elements of 6 group(Cr, Mo,W)  

International Nuclear Information System (INIS)

In this chapter authors investigated electrochemical characteristics of aluminium alloyed by chromium in medium of 3% NaCl solution, electrochemical characteristics of aluminium alloyed by molybdenum in medium of 3% NaCl solution and electrochemical characteristics of aluminium alloyed by tungsten in medium of 3% NaCl solution

2007-01-01

53

Increase of corrosion resistance of aluminium-lithium alloys by micro-alloying by calcium  

International Nuclear Information System (INIS)

Corrosion electrochemical behaviour of aluminium-lithium (6 % Li) alloy alloyed by calcium (0.01-0.5 %) in electrolyte (3, 0.3 and 0.03 % NaCl solutions) is investigated by potentiometric method. Calcium alloying anodic addition increases corrosion resistance of the alloy in electrolytes at 298 K. Calcium effect as effective anodic addition could be explained by its dissolution in the aluminium-lithium solid solution. It is determined that optimal concentration of calcium for increase of corrosion resistance of the alloys must be not more than 0.05 mass %

2003-04-01

54

Fast neutron activation analysis of silicon in aluminium alloys  

International Nuclear Information System (INIS)

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

1983-01-01

55

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)

1988-09-26

56

Investigation into sputtering of aluminium alloys under ion bombardment  

International Nuclear Information System (INIS)

Aluminium (99.99%) and Al-3% Li alloy samples were irradiated with 2.5 KeV argon and helium ions, ion current density being 200 ?A/cm"2 and the temperature of 300 deg C. Change of sample mass during sputtering was determined by gravimetric method. Al-3% Li alloy sputtering coefficient during irradiation with argon ions is reduced by a factor of 1.4, as compared to aluminium, and during irradiation with helium ions - by a factor of 2.4. Being applied to the sample with negative in reference to the chamber walls 50 V potential the alloy sputtering coefficient is decreased by 4 fold in comparison with pure aluminium. Observed effect is associated with lithium radiation-stimulated segregation resulting in sufficient enrichment of the surface with the light element - lithium. Secondary ion mass-spectrometry investigation showed that enriched layer is capable of continuous restoration during sputtering; this fact is important in practical use of aluminium-lithium alloys as a first wall material for plasma plants

1986-01-01

57

Determination of aluminium concentration in copper-aluminium alloys using ?-ray transmission techniques  

International Nuclear Information System (INIS)

Disk foils of copper aluminium alloys of 7.07 cm2 and thickness from 0.39 to 0.83 cm are used as targets for ?-rays photons of energies 81 and 356 keV. Single and dual energy transmission techniques were applied to determine the concentration of aluminium as a minor component. It is concluded that aluminium concentration can be determined with an accuracy of more than or equal to 98.53 and 99.09% in the cases of single and dual energy gamma-ray transmission techniques, respectively. The results of the two techniques are compared with results from chemical analysis. Discrimination between single and dual energy methods depends on the error due to the counting rate and mass thickness

2002-05-01

58

Determination of aluminium concentration in copper-aluminium alloys using {gamma}-ray transmission techniques  

Energy Technology Data Exchange (ETDEWEB)

Disk foils of copper aluminium alloys of 7.07 cm{sup 2} and thickness from 0.39 to 0.83 cm are used as targets for {gamma}-rays photons of energies 81 and 356 keV. Single and dual energy transmission techniques were applied to determine the concentration of aluminium as a minor component. It is concluded that aluminium concentration can be determined with an accuracy of more than or equal to 98.53 and 99.09% in the cases of single and dual energy gamma-ray transmission techniques, respectively. The results of the two techniques are compared with results from chemical analysis. Discrimination between single and dual energy methods depends on the error due to the counting rate and mass thickness.

El-Kateb, A.H. E-mail: ahelkatel@frcu.eun.eg; Rizk, R.A.M.; Abdul-Kader, A.M

2002-05-01

59

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Scientific Electronic Library Online (English)

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

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

60

Crystallographic orientation-spray formed hypereutectic aluminium-silicon alloys  

Directory of Open Access Journals (Sweden)

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

Hamilta de Oliveira Santos

2005-06-01

 
 
 
 
61

Characterisation of intermetallic inclusions obtained by dissolution of iron alloying additives in molten aluminium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Iron is an important and cost-effective alloying additive in aluminium alloys. However, for achieving high quality and rapid alloying of iron in the aluminium industry, particularly in state-of-the-art melting systems equipped with an electromagnetic pump (EMP), a fundamental understanding of the mechanism of dissolution of iron additives is essential. Commercial iron powder (AHC 100.29, supplier Höganäs AB, Sweden) and standard aluminium alloy AA 1050 in the form of 6mm strip (producer: Im...

Kevorkijan, Varuz?an

2012-01-01

62

Weldability of high strength aluminium-scandium alloys  

International Nuclear Information System (INIS)

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

2001-01-01

63

Advanced generation of green conversion coatings for aluminium alloys  

International Nuclear Information System (INIS)

Anticorrosive cerium based treatments have been proved as efficient green alternatives to those based on environmentally undesirable Cr(VI) compounds. Thus, full immersion in cerium salt solutions allows reaching similar protection level against aluminium alloys corrosion that chromates treatments. However, treatment time is too high for being considered in industrial applications. In this work, accelerated methods for obtaining cerium-rich conversion coatings on aluminium-magnesium alloys are proposed. The films developed have been characterised by SEM and EDS. These studies have revealed that the coatings have a mixed or heterogeneous nature, being composed of a layer of alumina covering the matrix, together with islands of cerium formed over the cathodic intermetallics that are present on the surface of the alloy. Furthermore, studies conducted employing electrochemical techniques indicate that the degree of protection provided by these coatings is several orders of magnitude superior to that achieved with other treatments

2004-11-15

64

Advanced generation of green conversion coatings for aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Anticorrosive cerium based treatments have been proved as efficient green alternatives to those based on environmentally undesirable Cr(VI) compounds. Thus, full immersion in cerium salt solutions allows reaching similar protection level against aluminium alloys corrosion that chromates treatments. However, treatment time is too high for being considered in industrial applications. In this work, accelerated methods for obtaining cerium-rich conversion coatings on aluminium-magnesium alloys are proposed. The films developed have been characterised by SEM and EDS. These studies have revealed that the coatings have a mixed or heterogeneous nature, being composed of a layer of alumina covering the matrix, together with islands of cerium formed over the cathodic intermetallics that are present on the surface of the alloy. Furthermore, studies conducted employing electrochemical techniques indicate that the degree of protection provided by these coatings is several orders of magnitude superior to that achieved with other treatments.

Bethencourt, M.; Botana, F.J.; Cano, M.J.; Marcos, M

2004-11-15

65

Aluminium alloys doped with lithium, copper and magnesium  

International Nuclear Information System (INIS)

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

1994-01-01

66

Application of a new aluminium alloy to nuclear research reactor  

International Nuclear Information System (INIS)

The WWRSM type research reactor of the Central Research Institute of Physics (KFKI, Budapest), installed 25 years ago, has been gone through a major reconstruction. During this process, the major structural material of several reactor components, called R - AlMgSi1 has been replaced by an upgraded aluminium alloy called R - AlMg2.5, the R referring to high purity. The properties of the original and replacement alloys are compared by an investigation of structural parts after long service life, and by laboratory tests of the new alloy. Finally, quality assurance measures for the structural materials in the KFKI research reactor are discussed. (R.P.) 5 tabs

1990-01-01

67

TEM microstructure investigations of aluminium alloys used as coating substrate  

Directory of Open Access Journals (Sweden)

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

T. Ta?ski

2013-01-01

68

Development of strength in solidifying aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Quantitative measurements of the strength development in the mushy-zone during solidification have been obtained in two commercial Al-Si alloys, AlSi7Mg and AlSi11Mg, an AlCu4 alloy and an AlMg5 alloy with a vane method. The results show that the material does not have any strength prior to dendrite coherency, confirming that the dendrites are free-floating and independent. Grain refining the AlSi7Mg and AlCu4 alloy postpones strength development, and strength increases slowly in the grain refined AlCu4 alloy. Adding Sr to the AlSi7Mg alloy postpones dendrite coherency and strength develops more slowly. Fading is observed to change the strength back towards that of the unmodified alloy with time. Adding 1% Si to the AlMg5 alloy postpones dendrite coherency, but the strength increases rapidly and makes the strength of the AlMg5Si1 alloy converge towards that of the AlMg5 alloy at increasing solid fractions. Strength develops very slowly in the AlSi11Mg alloy. The results are shown to be related to the size and morphology of the growing dendrites.

Dahle, A.K.; Arnberg, L. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Metallurgy

1997-02-01

69

Phase formation in multicomponent monotectic aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Alloys with a miscibility gap in the liquid state are potential materials for advanced bearings in automotive and other applications. While binary alloys, such as Al-Pb or Al-Bi, are well known, the information available for ternary monotectic Al-alloys is scarce. However, the phase formation in multicomponent alloys is not only more challenging from a scientific aspect, it is also a prerequisite for a focused development of advanced alloys. This motivated our detailed study of monotectic Al-Bi-Cu-Sn alloys including both experimental and computational thermodynamic methods. Based on the initially established systematic classification of monotectic ternary Al-alloys, the first promising monotectic reaction was observed in the ternary Al-Bi-Zn system. Further ternary systems Al-Cu-Sn, Al-Bi-Sn, Al-Bi-Cu and Bi-Cu-Sn were investigated as basis for quaternary Al-Bi-Cu-Sn alloys. Experimental investigations of phase equilibria, enthalpies and solidification microstructures were combined with thermodynamic modeling. The results demonstrate that the developed precise thermodynamic description is vital to reveal the distinct multicomponent monotectic features of pertinent phase diagrams. The solidification paths of ternary monotectic alloy systems, Al-Bi-Zn, Al-Sn-Cu and Al-Bi-Cu, were also studied using thermodynamic calculations, revealing specific details of phase formation during solidification of selected alloys.

Mirkovic, Djordje; Groebner, Joachim; Schmid-Fetzer, Rainer [Institute of Metallurgy, Clausthal University of Technology (Germany)

2008-07-01

70

Metallurgical Characterisation of Recovered Aluminium Alloys in Cameroon  

Directory of Open Access Journals (Sweden)

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

T. Tchotang

2013-07-01

71

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

72

Cerium molybdate nanowires for active corrosion protection of aluminium alloys  

International Nuclear Information System (INIS)

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

2012-05-01

73

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

74

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

DEFF Research Database (Denmark)

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

Singh, Bachu Narain; Horsewell, Andy

1986-01-01

75

Cavitation-aided grain refinement in aluminium alloys:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

76

Fatigue behavior of GMAW welded Aluminium alloy AA7020  

International Nuclear Information System (INIS)

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

2007-01-01

77

Grain boundary phenomena and failure of aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2001-01-01

78

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

International Nuclear Information System (INIS)

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

2002-08-11

79

Aluminium base amorphous and crystalline alloys with Fe impurity  

International Nuclear Information System (INIS)

Aluminium base alloys show remarkable mechanical properties, however their low thermal stability still limits the technological applications. Further improvement of mechanical properties can be reached by partial crystallization of amorphous alloys, which gives rise to nanostructured composites. Our work was focused on aluminium based alloys with Fe, Nb and V additions. Samples of nominal composition Al90Fe7Nb3 and Al94Fe2V4 were studied in amorphous state and after annealing up to 873 K. From Moessbauer spectra taken on the samples in amorphous state the value of f-factor was determined as well as corresponding Debye temperatures were calculated. Annealing at higher temperatures induced nano and microcrystalline crystallization. Moessbauer spectra of samples annealed up to 573 K are fitted only by distribution of quadrupole doublets corresponding to the amorphous state. An increase of annealing temperature leads to the structural transformation, which consists in growth of nanometer sized aluminium nuclei. This is partly reflected in Moessbauer parameters. After annealing at 673 K intermetallic phase Al3Fe and other Al-Fe phases are created. In this case Moessbauer spectra are fitted by quadrupole doublets. During annealing up to 873 K large grains of Fe-Al phases are created. (authors)

2006-06-11

80

LASER CLADDING ON ALUMINIUM BASE ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1991-01-01

 
 
 
 
81

RTR spent fuel reprocessing: Nitric acid dissolution of aluminium alloys  

International Nuclear Information System (INIS)

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

2003-03-09

82

Recent development in aluminium alloys for aerospace applications  

Energy Technology Data Exchange (ETDEWEB)

Driven by the increasing requirements from aircraft producers, Hoogovens Aluminium Rolled Products GmbH, together with Hoogovens Research and Development, has enhanced the property combinations of their aircraft materials. For these types of material, optimised processing routes as well as new alloy chemistries have been investigated. Whilst retaining the strength levels required by the aerospace industry, new processing routes offer major improvements in ductility, toughness, fatigue performance and in reduction of residual stress in large dimension plate and sheet products. A further goal of investigating new alloy chemistries is the trend towards new joining techniques such as welding and brazing for aircraft structures. These new joining techniques require different property combinations compared to the conventional aerospace alloys. In parallel to these improved processing routes and new alloy developments, new ultrasonic inspection techniques have been developed, which are able to predict fatigue performance and residual stress in thick plate products. (orig.)

Heinz, A.; Haszler, A.; Keidel, C. [Hoogovens Aluminium Rolled Products, Koblenz (Germany); Moldenhauer, S.; Benedictus, R.; Miller, W.S. [Hoogovens Research and Development (now part of Corus Group Plc), PO-Box 10 000, 1970 CA, IJmuiden (Netherlands)

2000-03-15

83

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

International Nuclear Information System (INIS)

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

1999-01-01

84

Fatigue properties of particle reinforced aluminium alloys  

International Nuclear Information System (INIS)

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

2000-01-01

85

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

Science.gov (United States)

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

Reed, R. P.

1972-01-01

86

New filler metals for brazing aluminium alloys; Neue Hartlote zum Loeten von Aluminiumlegierungen  

Energy Technology Data Exchange (ETDEWEB)

The use of light-weight design together with material mix in the automotive industrie demands the use of high strength aluminium alloys. Their relative low melting range limits the number of possible aluminium alloys and the achievable strength by using the common AISi12-brazing alloy. As part of a BMBF-project new aluminium brazing alloys with lower melting ranges are developed providing high strength brazing parts. The melting metallurgic produced brazing alloys can be used fluxless by MIG-brazing. Brazing with inert gas and flux can substitute AISi12-applications. This gives potential for improvement of brazing products and processes. (orig.)

Lugscheider, E.; Janssen, H.; Rojas, Y.; Silvanus, J.; Schubert, E. [RWTH, Aachen (Germany); Schmoor, H.; Stroiczek, M. [BrazeTec GmbH, Hanau (Germany)

2004-07-01

87

Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite  

International Nuclear Information System (INIS)

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

2011-01-17

88

Production technology of zirconium and aluminium-zirconium master alloy  

International Nuclear Information System (INIS)

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

1991-02-17

89

Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite  

Science.gov (United States)

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

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

2011-01-01

90

Study on the macrosegregation of aluminium in centrifugal-cast ZA27 alloy  

Energy Technology Data Exchange (ETDEWEB)

The macrosegregation of aluminium in centrifugal-cast ZA27 alloy under different conditions is examined. The longer the pouring time or the lower the pouring temperature, the lower the degree of the macrosegregation in the specimen. It is proposed that the macrosegregation of aluminium is caused due to the difference between the density of zinc and aluminium. The addition of manganese into the alloy could reduce the macrosegregation efficiently. (orig.) 11 refs.

Chen Gang; Zhu Zhengang [Academia Sinica, Hefei, AH (China). Inst. of Solid State Physics; Tong Mingduo [Department of Materials Science and Engineering, Northeastern University, Shenyang (China)

1999-06-15

91

Comparison of macrosegregation in titanium and aluminium alloy ingots  

Energy Technology Data Exchange (ETDEWEB)

The existing information shows that positive zonal segregation appears in titanium alloy ingots under the conditions of vacuum arc remelting. This segregation is characterized by enriching of central and upper ingot zones with elements having partition coefficient values noticeably less than unity (Cu, Ni, Cr, Fe, Si, Mn). Negative segregation (enriching of peripheral zones) of such elements as Cu, Mg, Zn, Si also having partition coefficient less the unity develops in continuous casting of aluminium alloy ingots. However, positive segregation also occurs in aluminium alloy ingots during vacuum arc remelting or continuous casting accompanied by vigorous metal stirring in molten pool. Analysis of these data and the results of investigations concerning copper, magnesium, Ni superalloys and steel ingots allowed one to validate the general model of zonal segregation. Values of the partition coefficient and solidification shrinkage, sizes of the transition region and the rate of metal movement in the molten pool are of prime importance. Various relationships of these parameters governs development of a type of macrosegregation (positive or negative) or production of a rather homogeneous ingot. (orig.) 11 refs.

Dobatkin, V.I.; Anoshkin, N.F. [All-Union Inst. of Light Alloys, Moscow (Russian Federation)

1999-05-15

92

Anodization of cast aluminium alloys produced by different casting methods  

Directory of Open Access Journals (Sweden)

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

K. Labisz

2008-08-01

93

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

94

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-07-01

95

The fracture of boron fibre-reinforced 6061 aluminium alloy  

Science.gov (United States)

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

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

1979-01-01

96

Ageing and fatigue behaviour in cast aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Microstructure evolution and loss in mechanical properties due to ageing, in cast aluminium alloys used by different manufacturers for cylinder-heads with various initial heat treatments and amount of copper was studied. Two of them have been chosen as references, namely AS7U3G T5 (ASTM319) and AS7G03 T7 (ASTM356). They were submitted to different heat treatments, from the as-received state to saturated ageing state and studied in fatigue, with hardness evolution and by TEM image analysis. After numerical identification, a link was made with microstructural evolutions. (orig.)

Barlas, B.; Cailletaud, G. [Centre des Materiaux de l' Ecole Nationale Superieure des Mines de Paris, UMR CNRS, Evry (France); Ovono-Ovono, D.; Guillot, I. [Univ. de Technologie de Compiegne, Lab. Roberval, UMR CNRS, Compiegne (France)

2002-07-01

97

Simultaneous spectrophotometric determination of titanium and scandium in aluminium alloys  

International Nuclear Information System (INIS)

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

1985-01-01

98

Friction stir welding of 6061 aluminium alloy  

International Nuclear Information System (INIS)

6061 AA (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance such as marine frames, pipelines, storage tanks, and aircraft components [1]. It is also used for the manufacturing of fuel elements in the nuclear research reactors. Compared to many of the fusion welding processes that are routinely used for joining structural alloys, friction stir welding (FSW) is a solid state joining process in which the material that is being welded is not melted and recast [2]. The welding parameters such as tool rotational speed, welding traverse speed, and tool profile play a major role in deciding the weld quality. Several FSW tools (differ from each other in pin angle, shoulder diameter, and shoulder concavity) have been used to fabricate a number of joints in order to obtain a tool with which a sound weld can be produced. It was found that the FSW tool with tapered cone pin, concave shoulder, and shoulder diameter equal to four times the welded plate thickness is suitable to produce a sound weld. The effect of the traverse speed on the global and local tensile properties of friction stir welded joints has been investigated in the 6061-T6 AA. The global tensile properties of the FSW joints were improved with increasing the traverse speed at constant rotation rate. It is found that the global tensile strength of the FSW joint is limited by the local tensile strength of 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

99

High rate constitutive modeling of aluminium alloy tube  

Science.gov (United States)

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

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

2006-08-01

100

Solidification and precipitation in aluminium-zirconium alloys. Pt. 2  

International Nuclear Information System (INIS)

In Al-Zr alloys on the basis of high-purity aluminium with 0.1 to 1.2 wt.% Zr the secondary precipitations were investigated after fast solidification of the samples and heat treatments of 200 to 5000C up to 300 h. At first spherical coherent particles appear consisting of the metastable cubic ZrAl3-phase with L12-structure. They lead to a noticeable precipitation hardening of the alloy in the temperature range from 300 to 4000C. After longer times and higher temperatures plate - or rod - like particles of the tetragonal ZrAl3 equilibrium phase appear. Attempts to reach the solution-annealed state again starting from the overaged heterogenised state failed because of the extraordinary slow approach to the equilibrium. Therefore a repeated precipication hardening was not possible. (orig.)

1977-03-01

 
 
 
 
101

Anisotropy and Inhomogeneity in Extrudates of Aluminium Alloys  

Directory of Open Access Journals (Sweden)

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

K. Macek

2000-01-01

102

Fabrication of superhydrophobic aluminium alloy surface with excellent corrosion resistance by a facile and environment-friendly method  

Science.gov (United States)

This work develops a facile and environment-friendly method for preparing the superhydrophobic aluminium alloy surface with excellent corrosion resistance. The superhydrophobic aluminium alloy surface is fabricated by the boiling water treatment and stearic acid (STA) modification. Results show that the boiling water treatment endows the aluminium alloy surface with a porous and rough structure, while STA modification chemically grafts the long hydrophobic alkyl chains onto the aluminium alloy surface. Just grounded on the micro- and nano-scale hierarchical structure along with the hydrophobic chemical composition, the superhydrophobic aluminium alloy surface is endued the excellent corrosion resistance.

Feng, Libang; Che, Yanhui; Liu, Yanhua; Qiang, Xiaohu; Wang, Yanping

2013-10-01

103

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

104

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

International Nuclear Information System (INIS)

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

1980-01-01

105

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

106

Metal dusting of binary iron aluminium alloys at 600 C  

Energy Technology Data Exchange (ETDEWEB)

In this work experiments on metal dusting of binary iron aluminium alloys with 15, 26 and 40 at.% Al were performed in strongly carburising CO-H{sub 2}-H{sub 2}O gas mixtures at 600 C. The mass gain kinetics was measured using thermogravimetric analysis (TGA). The carburised samples were characterised by means of light optical microscopy (LOM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was found that the mass gain kinetics depends on the CO content of the gas mixtures and on the Al content of the alloys. With decreasing carbon activity the carburisation reaction kinetics decreases and the onset of metal dusting is retarded for increasing time periods. With increasing Al content of the alloys the carburisation reaction is slower and metal dusting sets on at later times. The samples were not pre-treated for the formation of a protective oxide scale. By X-ray Photoelectron Spectroscopy (XPS) analyses of the carburised iron aluminium samples it was found that the formation of Al{sub 2}O{sub 3} layers has taken place in the CO-H{sub 2}-H{sub 2}O gas atmospheres. Needle- or plate-like {kappa}-phase (Fe{sub 3}AlC{sub x}) precipitates close to the surface of the carburised Fe-15Al sample were detected by means of XRD and LOM. The coke on top of the carburised samples mainly consists of filamentous carbon with metal particles at their tips. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Bernst, R.; Spiegel, M. [Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany); Schneider, A. [Salzgitter Mannesmann Forschung GmbH, Ehinger Str. 200, D-47259 Duisburg (Germany)

2006-09-15

107

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

International Nuclear Information System (INIS)

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

2000-01-01

108

High temperature corrosion behaviour of iron aluminides and iron-aluminium-chromium alloys  

Energy Technology Data Exchange (ETDEWEB)

The high temperature corrosion of different iron aluminides and iron-aluminium-chromium alloys containing between 6 and 17 wt% aluminium, 2 and 10 wt% chromium and additions of mischmetal has been investigated in air as well as in carburising, chlorinating and sulphidising environments. It was found that all alloys showed excellent corrosion resistance to both oxidation in air and carburisation in CH{sub 4}/H{sub 2} up to at least 1100 C and to sulphidation in SO{sub 2}/air up to at least 850 C. In these environments the corrosion behaviour is not influenced by the concentrations of aluminium and chromium. In oxygen deficient H{sub 2}S-atmospheres, however, the corrosion behaviour depends sensitively on the aluminium and chromium concentration. At least 12 wt% aluminium in chromium-free alloys or 10 wt% aluminium in alloys containing 10 wt% chromium are required to provide sulphidation resistance at 550 C. The chlorination resistance of iron-aluminium-chromium alloys is low due to their formation of volatile aluminium chlorides. (orig.)

Kloewer, J. [Krupp-VDM GmbH, Werdohl (Germany)

1996-12-01

109

Corrosion of aluminium alloys with calcium, strontium and barium in seawater  

International Nuclear Information System (INIS)

Corrosion behaviour of aluminium-calcium (strontium, barium) system alloys in seawater was investigated by electrochemical method with 1 mV x s-1 sweep speed. It is shown that displacement of stationary potential to the negative side is observed during aluminium alloying with alkaline metals. The rate of aluminium corrosion grows when the content of alloying elements exceeds 0.1 % in calcium-strontium-barium series. This leads to decrease of efficiency in protector-steel protective circuit of barium is substituted for calcium

1995-07-01

110

High effective organic corrosion inhibitors for 2024 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-15

111

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

Directory of Open Access Journals (Sweden)

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

S. Solay Anand

2011-07-01

112

Characterization of oxyde films and conversion layers on aluminium alloys  

International Nuclear Information System (INIS)

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

1993-11-01

113

Characterization of oxyde films and conversion layers on aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

Laet, J. de (Vrije Univ. Brussel, Dept. Metallurgy, Electrochemistry and Materials Science (Belgium)); Goeminne, G. (Vrije Univ. Brussel, Dept. Metallurgy, Electrochemistry and Materials Science (Belgium)); Terryn, H. (Vrije Univ. Brussel, Dept. Metallurgy, Electrochemistry and Materials Science (Belgium)); Vereecken, J. (Vrije Univ. Brussel, Dept. Metallurgy, Electrochemistry and Materials Science (Belgium))

1993-11-01

114

Precipitation kinetics in a severely plastically deformed 7075 aluminium alloy  

International Nuclear Information System (INIS)

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

2014-03-01

115

Cold Spray Deposition of Titanium onto Aluminium Alloys  

Scientific Electronic Library Online (English)

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

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

116

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

117

A new austenitic alumina forming alloy: an aluminium-coated FeNi32Cr20  

Energy Technology Data Exchange (ETDEWEB)

The FeCrAl alloys owe their low oxidation rate to the formation of a slow growing {alpha}-aluminium oxide scale. Therefore they are used, for example, as a substrate material in metal-supported automotive catalytic converters. Increasing exhaust gas temperatures mean that, in addition to the oxidation properties, high temperature mechanical properties should also be improved. Compared to the ferritic FeCrAl alloys, austenitic alloys possess the required high mechanical strength at higher temperatures. However for most commercially available materials the oxidation resistance is not sufficient due to a low aluminium content. High aluminium contents are avoided in austenitic alloys, since they cause severe workability problems, even at aluminium contents, which are below the necessary amount to get a pure alumina scale. The newly developed material Nicrofer 3220 PAl (coated FeNiCrAl) consists of an austenitic FeNi32Cr20 alloy coated with aluminium on both sides. It combines the outstanding oxidation resistance of an alumina forming FeCrAl alloy with the advantage of the high temperature strength of an austenitic alloy. Additionally the oxidation is even lower than the oxidation of the commercial grade Aluchrom YHf (FeCr20Al6) - conventional homogenous FeCrAl. Aluminium coated FeNiCrAl can easily be formed into its final shape. Prior to service, an in situ heat treatment is recommended in order to optimize the properties. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Hattendorf, H.; Kolb-Telieps, A. [ThyssenKrupp VDM GmbH, Altena (Germany); Hojda, R. [DIEHL-Metall, Hemer (Germany); Naumenko, D. [Forschungszentrum Juelich GmbH, IEF-2, Juelich (Germany)

2008-06-15

118

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

International Nuclear Information System (INIS)

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

1982-09-24

119

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 dura...

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

2013-01-01

120

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Schmidt, Helmut K.; Mu?ller, Peter; Dittfurth, Carola; Albayrak, Sener; Puhl, Anne

2000-01-01

 
 
 
 
121

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

2011-04-01

122

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

123

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

124

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Maros Martinkovic; Maria Kapustova

2012-01-01

125

Microstructure Scaling Properties and Fatigue Resistance of Pre-Strained Aluminium Alloys (Part 1: Al-Cu alloy)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract The objective of this work is to provide the link between the fatigue behaviour of pre-strained aluminium alloys and the scaling properties of damage induced on the fracture surface. Fatigue tests performed on pre-strained aluminium alloys revealed a large difference in their residual fatigue resistance linked to the material: the Al-Cu alloy demonstrated a sharp decrease of HCF life-time due to the pre-straining whereas the insensitivity of the Al-Mg alloy was clear. For ...

2010-01-01

126

Corrosion electrochemical behaviour of aluminium alloyed by 3-group elements. Corrosion electrochemical behaviour of alloys of Al-Ga, Al-In systems  

International Nuclear Information System (INIS)

In this chapter authors made conclusion that the activation of aluminium by addition of gallium and indium allow to wide use them for development protector alloys. Both of elements can be recommend as addition to aluminium as protector material

2007-01-01

127

Low distortion quenching of aluminium alloys in polymer medium  

Energy Technology Data Exchange (ETDEWEB)

One of the actual and practical problems during semi-products and parts quenching is distortion and residual stresses reduction. These problems are effectively decided by using an cooling aqueous polymer medium as regards thin sheet and extruded parts, forgings (having especially complex configuration). It is discussed the quenchant, containing additions of the two polymers in low concentration (up to 1,5%). The medium is distinguished by low expense and good cleaning of polymers. It has been examined the mechanism and cooling rate in the medium, quench sensitivity of aluminium alloys of different system. The mechanical properties (static, fatigue, crack resistance) and the corrosion characteristics of alloys and the products, designated for polymer quenching, has been investigated. The medium allows to reduce distortion of sheet parts by 3-5 times and to decrease the level of residual stresses in forging up to 50% due to increasing of uniformity and stability of the cooling process. The cooling rate is enough high for obtaining optimum structure and thus for ensuring the properties. (orig.)

Senatorova, O.G.; Sidelnikov, V.V.; Fridlyander, I.N. [All - Russian Inst. of Aviation materials (VIAM), Moscow (Russian Federation); Mihailova, I.F.; Tihonova, L.A. [Novosibirskyi Inst. of Organic Chemistry (NIOH), Russian Academy of Science, Novosibirsk (Russian Federation); Bedarev, A.S.; Spector, J.I. [National Russian Inst. of Aviation Technologies (NIAT), Moscow (Russian Federation)

2002-07-01

128

Analysis of the influence oxygen and hydrogen during melting aluminium and his alloys  

Directory of Open Access Journals (Sweden)

Full Text Available In the work was stated term the analysis of ion influences in melting codnuction of aluminium and his alloys. Influence from hydrogen and oxygen, hydrogen and oxygen and steam water together was distinguished. Where have worked out the scheme of influences leading to gas porosity of aluminium and his alloys. In analysis was referred to theory of double electric layer. It was conducted the analysis regularity of opinion influence oxygen and hydrogen in melt aluminium in support on Allena - Hewitta dependence.

A. W. Byda?ek

2011-07-01

129

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)

1993-09-01

130

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

International Nuclear Information System (INIS)

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

1992-01-01

131

Severe wear of a near eutectic aluminium-silicon alloy  

Energy Technology Data Exchange (ETDEWEB)

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

Mahato, Anirban [Mechanical Engineering Department, Indian Institute of Science, Bangalore 560 012 (India); Verma, Nisha; Jayaram, Vikram [Material Engineering Department, Indian Institute of Science, Bangalore 560 012 (India); Biswas, S.K., E-mail: skbis@mecheng.iisc.ernet.in [Mechanical Engineering Department, Indian Institute of Science, Bangalore 560 012 (India)

2011-09-15

132

Excimer laser treatment for aluminium alloy mechanical property enhancement  

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-03-01

133

Severe wear of a near eutectic aluminium-silicon alloy  

International Nuclear Information System (INIS)

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

2011-09-01

134

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

135

Electrochemical behaviour of aluminium alloys containing indium and tin in NaCl solution  

International Nuclear Information System (INIS)

The electrochemical behaviour of Al, Al-In, Al-Sn and Al-Sn-In alloys in 2 M NaCl solution has been studied using an open circuit potential, potentiodynamic polarization and ac impedance measurements as well as by optical microscopy examination. The addition of alloying components to aluminium produced in all cases a considerable activation of aluminium. The activation is manifested by shifting the open corrosion potential and the pitting potential in the negative direction (for about 0.6 V) and significant reducing of the passive potential region. The degree of activation depended on alloying element and it was found that there is an increase in the order: Al 3+/Al potential. The ac impedance measurements performed at different potentials in wide potential range (corresponding to passive and active state of each examined samples) confirmed the great activity of Al-Sn and Al-Sn-In alloys compared to aluminium.

2010-06-01

136

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-09-01

137

Friction and corrosion resistance of sputter deposited supersaturated metastable aluminium-molybdenum alloys  

Energy Technology Data Exchange (ETDEWEB)

Two closed field unbalanced magnetrons with targets of aluminium and molybdenum have been used for the co-deposition of aluminium-molybdenum coatings with different compositions. A pin on disk machine and a computer controlled potentiostat have been used to evaluate respectively, the tribological and corrosion properties of the deposited alloys. Results have shown that introducing molybdenum into aluminium coatings improves their poor tribological properties. Aluminium-molybdenum coatings with different compositions have shown low wear behaviour and for coatings with high molybdenum contents (> 80%) friction coefficients against steel, as low as 0.18 have been obtained. The addition of molybdenum into aluminium coatings has reduced their corrosion tendency and corrosion current density in a marine environment. (orig.)

Abu-Zeid, O.A. [Univ. of the United Arab Emirates, Al-Ain (United Arab Emirates). Dept. of Mech. Eng.; Bates, R.I. [Design, Mfg. and Marketing Research Inst., Univ. of Salford (United Kingdom)

1996-12-15

138

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

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Jellesen, Morten Stendahl

2014-01-01

139

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2006-01-01

140

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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

1986-03-01

142

Microstructure and mechanical properties of C355.0 cast aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The main task of this work was to study the solidification process through analysis of the DSC curves that were obtained at solidification rate of 5 K/min. During C355.0 alloy solidification an amount of different intermetallic phases may form. Their volume fraction, chemical composition and morphology exert significant influence on a technological and mechanical properties of the aluminium alloys. Therefore the examination and identification of intermetallic phases in examined alloy...

2011-01-01

143

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

International Nuclear Information System (INIS)

A process for guaranteeing sub-critical arrangements of nuclear fuel in tranport and/or storage containers is described, in which a homogeneous distribution of neutron poison in the aluminium matrix is guaranteed. A homogeneous mixture of aluminium powder and neutron poison powder is produced, this is pressed into plates in several stages, dried and made into hollow aluminium profiles of rectangular cross-section. The open ends of the hollow profile are then closed and this is rolled to the required dimension at 470-500"0C. (orig./HP)

1984-03-01

144

High strain rate superplasticity of AlN particulate reinforced aluminium alloy composites  

Energy Technology Data Exchange (ETDEWEB)

Ceramic whisker or particulate reinforced aluminium alloy composites have a great potential for automobile engineering components, aerospace structures, semi-conductor packaging and so on, because of the composites ability to exhibit a high specific elastic modulus and specific tensile strength, excellent wear resistance and heat resistance, low thermal expansion and good dimensional stability. A serious problem involving practical application of ceramic whisker or particulate reinforced aluminium alloy composites is due to the low tensile ductility, fracture toughness at room temperature and, also, their hardness qualities that make it difficult to deform by conventional forming processing and machining by ordinary tools. It has been found, however, that aluminium alloy composites reinforced by SiC or Si[sub 3]N[sub 4] whiskers or particulates produce superplasticity at a high strain rate of about 0.1s[sup [minus]1]. Superplastic deformation mechanisms of the ceramic whisker or particulate reinforced aluminium alloy composites are fine grain boundary sliding, interfacial sliding at a liquid phase and dynamic recrystallization. An AlN particulate reinforced aluminium alloy composite exhibits a high elastic modulus and a high thermal conductivity, and their thermal expansion is similar to silicon in that the AlN particulate reinforced aluminum alloy composite is expected to apply to semi-conductor packaging in the aerospace structure. In addition, if the composite could produce superplasticity at high strain rates, the market of aerospace application for superplastic composites could be expanded. The purpose of this study is to make clear if an AlN particulate reinforced aluminium alloy composite can produce superplasticity at high strain rate and the superplastic characteristics.

Imai, T. (National Industrial Research Inst. of Nagoya (Japan)); L' Esperance, G.; Hong, B.D. (Ecole Polytechnique de Montreal, Quebec (Canada))

1994-08-01

145

Nitridation of high-chromium steels alloyed with aluminium  

International Nuclear Information System (INIS)

The effect of aluminium on the shaping, kinetics of formation, structure and certain properties of nitrided OKh13 and 4Kh13 steels was investigated. The addition of 0.5% aluminium accelerates saturation of the steels with nitrogen and results in diffusion layers with better hardness and corrosion resistance properties. (author)

1974-12-01

146

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

International Nuclear Information System (INIS)

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

1979-01-01

147

Study of aluminium and titanium total quantity ratio effect on the technological plasticity of high alloyed nickel heat resisting alloys  

International Nuclear Information System (INIS)

To understand the effect of the total aluminium and titanium content on the standard plastisity of heat-resistant alloys added with refractory elements (tungsten, molybdenum, cobalt, niobium) ingots 160 mm in diameter have been studied, obtained by the VAM method with the content of ? Ti+Al=0-8%. An aluminium-and titanium-free alloy has a satisfactory plastisity in the test temperature interval 950-1200deg C. At an increased combined content of these metals the standard plastisity falls within the entire test temperature interval. The temperature interval of the maximum standard plastisity becomes tangibly narrower as ? Al+Ti increases. The change of the microhardness of heatresistant alloys added with tungsten, molybdenum, cobalt, niobium correlates with plastisity variation depending on the total content of aluminium and titanium

1976-01-01

148

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zhu, G.

2012-01-01

149

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

150

HIGH PURITY ALUMINIUM-LITHIUM MASTER ALLOY BY MOLTEN SALT ELECTROLYSIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1987-01-01

151

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

International Nuclear Information System (INIS)

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

2010-06-15

152

Formation enthalpies of liquid binary alloys of aluminium and tin with lanthanum  

International Nuclear Information System (INIS)

Concentration dependences of partial enthalpies of component solution and integral enthalpies of formation of liquid binary alloys of lanthanum with aluminium (from 54 to 100 at.% Al at 1920 K) and with tin (from 65 to 100 at.% Sn at 1890 K) from liquid components are studied with the help of a high-temperature tight calorimeter with an isothermal coating. It is established that the first enthalpy of molten lanthanum solution in liquid aluminium constitutes -135+-5, and in liquid tin is equal to -140+-6 kJ/g.at. Minimum value of integral enthalpy of formation of aluminium liquid alloys with lanthanum detected by extrapolation of experimental data constitutes approximately -46 kJ/g.at and corresponds to the alloy with xsub(La) approximately 0.54

1981-06-01

153

Characteristics of cyclic crack resistance of aluminium alloys at combined modes of biaxial loading  

Energy Technology Data Exchange (ETDEWEB)

A complex quantative assessment of the effect of the stressed state type and of the angle of the initial crack orientation on the rate of its extension has been conducted for eight aluminium alloys AMr6, O1420T, 1163AT, D16YAT, 1163ATVMO, O1419, 1201AT, and V95AT1 at combined biaxial tension modes. A new dimensionless parameter of cyclic crack resistance has been introduced and substantiated. The existence of a common dependence of the crack growth rate on the proposed parameter for all studied aluminium alloys with different mechanical properties has been established. 15 refs.

Shlyannikov, V.N. [Kazanskij Fiziko-Tekhnicheskij Inst KNTs RAN, Kazan` (Russian Federation)

1994-03-01

154

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

International Nuclear Information System (INIS)

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

2003-07-01

155

Aluminium alloys welding with high-power Nd:YAG lasers  

International Nuclear Information System (INIS)

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

1998-01-01

156

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

International Nuclear Information System (INIS)

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

2003-01-01

157

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2012-01-01

158

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

Directory of Open Access Journals (Sweden)

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

Prantik Mukhopadhyay

2010-05-01

159

Corrosion behaviour of aluminium alloyed by 7-8 group elements. Corrosion electrochemical behaviour of alloys of Al-Fe system  

International Nuclear Information System (INIS)

In this chapter authors investigated the influence on corrosion electrochemical characteristics of aluminium in the medium of 3% NaCl solution, polarization curves of aluminium and it's alloys with iron, meaning of different-effect (D) of alloys of Al-Fe system

2007-01-01

160

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

Directory of Open Access Journals (Sweden)

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

G. Venkateswarlu

2010-07-01

 
 
 
 
161

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

2006-01-01

162

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

International Nuclear Information System (INIS)

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

1992-01-01

163

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

CERN Multimedia

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

164

Evaluation Of Four Welding Arc Processes Applied To 6061 Aluminium Alloy  

International Nuclear Information System (INIS)

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

2011-01-17

165

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

International Nuclear Information System (INIS)

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

2003-11-10

166

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

2013-01-01

167

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Smith, A.

1987-01-01

168

Arc welding of high strength aluminium alloys for armour systems applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Pickin, Craig Graeme

2011-01-01

169

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Laukli, Hans Ivar

2004-01-01

170

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Laukli, Hans Ivar

2004-01-01

171

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-04-01

172

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

International Nuclear Information System (INIS)

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

2014-01-01

173

Thermal-mechanical fatigue behaviour of the cast aluminium alloy AlSi7Mg  

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-07-01

174

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

International Nuclear Information System (INIS)

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

1978-09-29

175

Spectrochemical determination of impurities in aluminium alloys by DC arc technique  

International Nuclear Information System (INIS)

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

176

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

Directory of Open Access Journals (Sweden)

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

J. Horsinka

2011-04-01

177

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

International Nuclear Information System (INIS)

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

2012-11-20

178

Application of aluminium alloys to the car body to lighten the weight and the problem of the aluminium welding. Shatai keiryoka no tameno aluminium gokin no tekiyo to sono yosetsu no mondaiten  

Energy Technology Data Exchange (ETDEWEB)

In this article, the application of aluminium and aluminium alloys (hereafter referred to as aluminium alloys) and its problematical points mainly aiming at weight reduction of vehicles are explained roughly. Concerning aluminium railway vehicles, about 6,000 vehicles have so far been actually used and this kind of vehicle will become increasingly important in the future era of super high speed railway vehicles. The weight reduction of railway vehicles brings such synergistic effects as preservation of the environment, improvement of its travelling performance and reduction of costs for power installation and electric overhead line installation. For the above weight reduction, aluminium alloy material and its junction are essential, hence in this article, the physical properties, the mechanical properties, the future and weldability of various aluminium alloys, and the usage of these alloys which are roughly classified into expansion material and cast material are outlined. Furthermore, as its joining techniques, fusion welding (inert gas arc welding, electron beam welding and laser welding), pressure welding (resistance spot welding, friction welding, ultrasonic welding and explosive welding) as well as welding defects are explained. 17 refs., 6 figs., 12 tabs.

Matsumoto, J. (Nikkei Techno-Research Co. Ltd., Shizuoka (Japan))

1993-05-25

179

Microstructural and strength study of MIG welded unions of aluminium alloy AW7020, as a function of joint geometry  

International Nuclear Information System (INIS)

Medium strength AW7XXX aluminium alloys are widely used as welded structures and in transportation. The applications of these alloys are limited by the behavior of the welded joints. There is not an agreement on the joint geometry that must be used on the 5 mm aluminium welds. The microhardness evolution is one of the most important strength indicator. For this reason, the aim of this work is to study the welded joint geometry influence on microhardness profile and on microstructure of a welded aluminium alloy AW7020 MIG, filled with AW5356. (Author) 16 refs

2000-01-01

180

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

International Nuclear Information System (INIS)

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

1979-01-01

 
 
 
 
181

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

182

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

183

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

Science.gov (United States)

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

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

2009-05-01

184

Elaboration in the area of aluminium containing alloys  

International Nuclear Information System (INIS)

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

2002-01-01

185

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

Directory of Open Access Journals (Sweden)

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

A. Zyska

2011-07-01

186

Deformation processing of high silicon of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The present work reports the effects of Sr on the microstructure and the tensile properties of deformed high silicon alloys (>12 mass%). Results have shown that deformation processing (hot and cold rolling) increases the strength and the ductility of eutectic and hypereutectic Al-Si alloys. The addition of Sr (0.02 mass%) to these alloys also improves the ductility significantly. The presence of coarse primary silicon crystals lowers the tensile properties of the deformed alloys, the ductility, in particular. (orig.)

Mulazimoglu, M.H. (McGill Univ., Montreal, Quebec (Canada)); Gruzleski, J.E. (Dept. of Mining and Metallurgical Engineering, McGill Univ., Montreal, PQ (Canada))

1993-11-01

187

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

Science.gov (United States)

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

Rabah, Mahmoud A

2004-01-01

188

Effect of irradiation on the deformation of copper and copper-aluminium alloys  

International Nuclear Information System (INIS)

The effect of low-temperature irradiation ( 1 MeV) at a temperature less than 70"0C. All irradiated and unirradiated specimens were pulled. A large increase in critical shear stress due to irradiation was observed; the increase was smaller in Cu-0.19 wt% Al alloy than in pure copper and Cu-0.09 wt% Al alloy. Ultimate shear stress and shear strain were less influenced by irradiation. Yield points were observed in all irradiated specimens. The yield drop was large in irradiated pure copper, and decreased with the increase of aluminium content in copper-aluminium alloys. All unirradiated specimens showed a high work-hardening coefficients (n) in the beginning of the deformation, followed by a lower value. By irradiation, the first value drastically decreased, while the second remained nearly constant. Shear stress and shear strain were influenced by crystal orientation. (orig.)

1982-01-01

189

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

Directory of Open Access Journals (Sweden)

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

Nagli? I.

2009-07-01

190

Study of aluminium alloys exposed to hydrogen plasma fluxes by secondary ion mass-spectrometry  

International Nuclear Information System (INIS)

Using the method of secondary ion mass-spectrometry the process of implantation is studied on specimens of aluminium (A999) and its alloys (Al-1.9Li-1.8Cu-0.9Mg; Al-2.75Li-2.67Be-2.28Mg; Al-2.1Li-5.54Mg; Al-2.0Li-2.5Cu) irradiated with a polyenergetic (2-20 keV) hydrogen particle flux generated by a high-voltage glow discharge. The penetration depth is revealed to be 14 ?. For aluminium and its alloys the concentration profiles of hydrogen absorbed under irradiation are obtained. It is shown that a degree of hydrogen atom capture is higher for the alloys and depends on their chemical composition. The observed increase of specimens mass after irradiation is associated with hydrogen particle capture as well as with oxide Li2O formation

2001-01-01

191

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

Directory of Open Access Journals (Sweden)

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

Libor Trško

2013-12-01

192

Electroformation of integrally coloured oxide films on aluminium alloys in aqueous acid solutions  

International Nuclear Information System (INIS)

The characteristics of the coloured anodic oxide films formed on aluminium alloys using integral anodizing processes are analysed. Anodization is achieved employing different acid electrolyte solutions and combined electrical perturbation programs to extend the colour tone range of the surface finishings. Colour measurements, energy dispersive x-ray analysis, electron - probe microanalysis, and SEM observations were performed to determine the influence performed to determine the influence of both electrolyte bath composition and anodizing electrical conditions on the aluminium oxide properties. (C.L.B.)

1984-04-15

193

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

194

Investigation into the strength of components made of UFG aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2008-01-01

195

Mechanical Properties of Aluminium-Uranium Alloy and Aluminium Commercially Pure at Several Temperatures.  

Science.gov (United States)

The mechanical properties of Ai-U (18,4 wt %) alloy with and without heat treatment were determined, and they were compared with the mechanical properties of aluminum alloy of commercial purity, AI-1100, at tempiratures of 25, 500, 550 and 600 exp 0 C, th...

N. F. de Quadros

1976-01-01

196

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

Energy Technology Data Exchange (ETDEWEB)

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

Enz, Josephin

2012-07-01

197

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

Directory of Open Access Journals (Sweden)

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

F. Musharavati

2010-07-01

198

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

199

Modelling research of hydrogen desorption from liquid aluminium and its alloys  

Directory of Open Access Journals (Sweden)

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

M. Saternus

2011-10-01

200

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

 
 
 
 
201

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Schubert, Thomas; Lorenz, Bernd; Steger, Ju?rgen; Weißga?rber, Thomas; Neugebauer, Reimund; Kieback, Bernd

2012-01-01

202

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

International Nuclear Information System (INIS)

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

2009-01-01

203

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

204

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

Science.gov (United States)

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

Harrigan, John; Millett, Jeremy; Bourne, Neil

2007-06-01

205

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

International Nuclear Information System (INIS)

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

1987-01-01

206

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

Science.gov (United States)

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

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

2014-05-28

207

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

Energy Technology Data Exchange (ETDEWEB)

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

Liu, Meng; Klobes, Benedikt; Maier, Karl [Helmholtz-Institut fuer Strahlen- und Kernphysik, Rheinische Friedrich-Wilhelms-Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany)

2010-07-01

208

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

International Nuclear Information System (INIS)

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

2010-03-21

209

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

Directory of Open Access Journals (Sweden)

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

Benoit Alexandre

2013-11-01

210

ATOM-PROBE STUDY OF ALUMINIUM-LITHIUM ALLOYS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1988-01-01

211

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

212

Microstructure and mechanical properties of wrought aluminium alloy prepared by recycling of aluminium matrix composites reinforced with Inconel 601 fibres  

Energy Technology Data Exchange (ETDEWEB)

The microstructure and mechanical properties of Al-2.2Cu-1.7Mg-1.1Ni-1.1Fe-0.9Si-0.3Zn-0.2Cr-0.2Mn-0.2Ti (wt.%) alloy prepared by recycling of composite scrap containing Inconel 601 fibres in aluminium matrix were investigated. The structure of recycled alloy consisted of {alpha}-Al dendrites and a multiphase interdendritic region. Transmission electron microscopy and energy dispersive X-ray spectroscopy showed that the interdendritic region contained coarse Al{sub 9}Fe(Ni, Si), Al{sub 7}Cu{sub 4}Ni, Al{sub 4}CuMg{sub 5}Si{sub 4}, (Cu, Al){sub 2}Mg and Mg{sub 2}Si intermetallic phases distributed in the {alpha}-Al matrix. Heat treatments resulted in additional hardening of the alloy through the precipitation and growth of fine {theta}-Al{sub 2}Cu, S-Al{sub 2}CuMg and {beta}-Mg{sub 2}Si intermetallic particles in the {alpha}-Al matrix. Peak microhardness, hardness and yield strength values were reached after 20, 12 and 8 h ageing at 180, 190 and 200 C, respectively. During the early stages of plastic deformation both intermetallic particles in the interdendritic region and small precipitates in the {alpha}-Al matrix contributed to the high strain hardening of the alloy. The breakage of coarse intermetallic particles resulted in a considerable reduction of the strain hardening exponent and quasi-steady strain hardening rate. The alloy failed by the coalescence of cavities formed within broken intermetallic particles and small voids formed around the precipitates. (orig.)

Lapin, J.; Pelachova, T. [Slovak Acad. of Sci., Bratislava (Slovakia). Inst. of Mater. and Machine Mech.

1999-11-01

213

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

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Jellesen, Morten Stendahl

214

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 H_2SO_4 at 40 and 100"0C are considered. Current density vs potential and corrosion rate vs potential potentiostatic curves plotted in 75 percent H_2SO_4 at 140"0C 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 H_2SO_4 at 140"0C is an exponential function of the atomic content of the alloying components (Ti, Al) in them; aluminum vitiates the corrosion resistance very strongly

215

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2006-01-01

216

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

Directory of Open Access Journals (Sweden)

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

Mojisola O. Nkiko

2011-11-01

217

Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys  

Directory of Open Access Journals (Sweden)

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

E. Matykina

2010-01-01

218

Mechanical properties and corrosion behaviour of MIG welded 5083 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-01

219

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

Scientific Electronic Library Online (English)

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

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

220

Phase composition and thermodynamic properties of gadolinium-aluminium alloys  

International Nuclear Information System (INIS)

Phase composition and thermodynamic properties of all the compounds of Gd-Al system in the temperature range from 673 to 873K were studied by the method of e.m.f. measurement. In the process of gadolinium electrodeposition on aluminium the presence of solid solution of Gd2, Al, Gd3, Al2, GdAl, GdAl2 and GdAl3 intermetallic compounds has been determined. The possible compound of Gd2Al3 composition has been identified. The partial molar thermodynamic characteristics of gadolinium in the compounds were calculated using e.m.f. temperature dependences

1979-01-01

 
 
 
 
221

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

Science.gov (United States)

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

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

1998-09-01

222

Influence of quench rate and microstructure on bendability of AA6016 aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of the quench rate after solution treatment on the bendability of AA6016 aluminium alloy sheets was investigated. Crack initiation during bending tests is found to be independent of quench rate whereas crack propagation is decreased after rapid quenching. A quantitative analysis of microstructures was carried out by transmission electron microscopy, focusing on grain boundary precipitates to correlate bending properties with microstructure. Crack initiation occurs by voiding at ...

Castany, Philippe; Diologent, Fre?de?ric; Rossoll, Andreas; Despois, Jean-franc?ois; Bezenc?on, Cyrille; Mortensen, Andreas

2013-01-01

223

Hot-crack test for aluminium alloys welds using TIG process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

224

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1993-01-01

225

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

International Nuclear Information System (INIS)

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

1988-01-01

226

Electrochemical Estimation of the Corrosion Rate of Magnesium/Aluminium Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

227

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Fair, G. H.

1988-01-01

228

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1993-01-01

229

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Xin Shi-gang, Zhao Rong-gen

2009-01-01

230

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1993-01-01

231

Elemental analysis of aluminium based alloys using 14-MeV neutrons  

International Nuclear Information System (INIS)

The elemental concentration of aluminium based alloy samples was estimated using 14-MeV neutron activation analysis. The analysis was carried out by the method of standard addition. The elements, zinc, manganese and copper were detected at wavelength 213.9 nm, 279.5 nm and 324.7 nm, respectively. The results are in agreement with those obtained by atomic absorption spectroscopy. (author) 5 refs.; 3 tabs

1988-07-01

232

High-Rate Compaction of Aluminium Alloy Foams  

International Nuclear Information System (INIS)

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

2006-07-28

233

High-Rate Compaction of Aluminium Alloy Foams  

Science.gov (United States)

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

Harrigan, J. J.; Hung, Y.-C.; Tan, P. J.; Bourne, N. K.; Withers, P. J.; Reid, S. R.; Millett, J. C. F.; Milne, A. M.

2006-07-01

234

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2012-01-01

235

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

236

Tribological Properties of Aluminium 2024 Alloy Beryl Particulate MMC's  

Directory of Open Access Journals (Sweden)

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

H.B. Bhaskar

2012-12-01

237

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

International Nuclear Information System (INIS)

An instrumental determination of boron in Al and Al-Mg alloy by proton activation using the reaction "1"0B(p,?)"7Be is described. Pellets, pressed from boric acid are used as a standard. This method is compared with two destructive methods, based on the "1"0B("4He,n)"1"3N and "1"0B(d,n)"1"1C reactions. The agreement between the different methods is satisfactory. The boron concentration was 1.2 and 66 ?g/g"-"1 for Al and Al-Mg alloy respectively. The results for Al-Mg alloy were also compared with photometry and flame emission spectrometry. Under the activation of B.C.R. of the Commission of European Communities, the possibilities for the preparation and analysis of a certified reference material for boron in Al alloys are being investigated. As different undependent and absolute analytical techniques are required, methods based on 3 different nuclear reactions were developed. (orig./RB)

1980-06-13

238

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

Science.gov (United States)

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

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

2005-02-01

239

Advances in aluminium alloy products for structural applications in transportation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-11-01

240

Advances in aluminium alloy products for structural applications in transportation  

International Nuclear Information System (INIS)

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

1993-11-01

 
 
 
 
241

Advances in aluminium alloy products for structural applications in transportation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Staley, J.; Lege, D.

1993-01-01

242

A predictive fatigue life model for anodized 7050 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

243

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

Science.gov (United States)

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

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

2013-09-01

244

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

International Nuclear Information System (INIS)

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

2008-10-01

245

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2000-01-01

246

Analysis of low cycle fatigue in AlMgSi aluminium alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2004-01-01

247

Phase composition of aluminium rich Al-Li-Mg-Si alloys  

International Nuclear Information System (INIS)

Al-Li-Mg-Si alloys with constant lithium (2,5%) content and variable-magnesium and silicon (7,5% and 3,5% respectively) contents after annealing at 430 deg C are studied. Cross-section of isothermal tetrahedron of Al-Li-Mg-Si system with constant lithium content 2,5% at 430 deg C is plotted. Phases: AlLi, Al2LiMg, AlLiSi and Mg2Si in Al-Li-Mg-Si alloys in the concentration region studied are at equilibrium with solid solution on aluminium base

1994-01-01

248

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

Directory of Open Access Journals (Sweden)

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

Palomino Luis Enrique M.

2003-01-01

249

Precipitation hardening of cast Zr-containing A356 aluminium alloy  

International Nuclear Information System (INIS)

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

2011-02-01

250

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

International Nuclear Information System (INIS)

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

2012-11-22

251

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

252

Increasing of founding properties of secondary aluminium alloys  

Directory of Open Access Journals (Sweden)

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

O.V. Lyutova

2013-06-01

253

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

254

Structural properties of molten dilute aluminium-transition metal alloys  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-07-19

255

Structural properties of molten dilute aluminium-transition metal alloys.  

Science.gov (United States)

The short-range order in liquid binary Al-rich alloys (Al-Fe, Al-Ti) was studied by x-ray diffraction. The measurements were performed using a novel containerless technique which combines aerodynamic levitation with inductive heating. The average structure factors, S(Q), have been determined for various temperatures and compositions in the stable liquid state. From S(Q), the pair correlation functions, g(r), have been calculated. The first interatomic distance is nearly temperature-independent, whereas the first-shell coordination number decreases with increasing temperature for all the alloys investigated. For the Al-Fe alloys, room-temperature scanning electron microscropy (SEM) studies show the formation of a microstructure, namely the existence of Al(13)Fe(4) inclusions in the Al matrix. PMID:21690847

Pozdnyakova, I; Hennet, L; Mathiak, G; Brillo, J; Zanghi, D; Brun, J-F; Brassamin, S; Bytchkov, A; Cristiglio, V; Véron, E; Matzen, G; Geandier, G; Thiaudière, D; Moss, S C; Spaepen, F; Egry, I; Price, D L

2006-07-19

256

Structural properties of molten dilute aluminium-transition metal alloys  

International Nuclear Information System (INIS)

The short-range order in liquid binary Al-rich alloys (Al-Fe, Al-Ti) was studied by x-ray diffraction. The measurements were performed using a novel containerless technique which combines aerodynamic levitation with inductive heating. The average structure factors, S(Q), have been determined for various temperatures and compositions in the stable liquid state. From S(Q), the pair correlation functions, g(r), have been calculated. The first interatomic distance is nearly temperature-independent, whereas the first-shell coordination number decreases with increasing temperature for all the alloys investigated. For the Al-Fe alloys, room-temperature scanning electron microscropy (SEM) studies show the formation of a microstructure, namely the existence of Al13Fe4 inclusions in the Al matrix

2006-07-19

257

Phase-oriented surface segregation in an aluminium casting alloy  

International Nuclear Information System (INIS)

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

2009-02-15

258

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

International Nuclear Information System (INIS)

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

1987-01-01

259

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.

C. Ozarpa

2007-01-01

260

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Science.gov (United States)

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

Cheng, Feng; Jiang, Shuyun; Liang, Jun

2013-09-01

 
 
 
 
261

Stereometry specification of anodisation surface of casting aluminium alloys  

Directory of Open Access Journals (Sweden)

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

J. Konieczny

2008-04-01

262

Microstructures and mechanical properties of an Osprey aluminium 7000 alloy  

International Nuclear Information System (INIS)

An alloy from the 7000 serie obtained by the Osprey process has been studied both from the microstructural (TEM, SAXS) and from the mechanical viewpoint. The modelling of the mechanical properties and of their anisotropy was performed using both models from physical metallurgy and a self consistent elastoplastic model. (orig.)

1993-11-01

263

Microstructures and mechanical properties of an Osprey aluminium 7000 alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An alloy from the 7000 serie obtained by the Osprey process has been studied both from the microstructural (TEM, SAXS) and from the mechanical viewpoint. The modelling of the mechanical properties and of their anisotropy was performed using both models from physical metallurgy and a self consistent eslastoplastic model.

Cottignies, L.; Brechet, Y.; Audier, M.; Livet, F.; Louchet, F.; Sainfort, P.

1993-01-01

264

Microstructures and mechanical properties of an Osprey aluminium 7000 alloy  

Energy Technology Data Exchange (ETDEWEB)

An alloy from the 7000 serie obtained by the Osprey process has been studied both from the microstructural (TEM, SAXS) and from the mechanical viewpoint. The modelling of the mechanical properties and of their anisotropy was performed using both models from physical metallurgy and a self consistent elastoplastic model. (orig.).

Cottignies, L. (LTPCM/ENSEEG, Domaine Univ. de Grenoble, 38 St Martin d' Heres (France) CRV Pechiney, 38 Voreppe (France)); Brechet, Y. (LTPCM/ENSEEG, Domaine Univ. de Grenoble, 38 St Martin d' Heres (France)); Audier, M. (LTPCM/ENSEEG, Domaine Univ. de Grenoble, 38 St Martin d' Heres (France)); Livet, F. (LTPCM/ENSEEG, Domaine Univ. de Grenoble, 38 St Martin d' Heres (France)); Louchet, F. (LTPCM/ENSEEG, Domaine Univ. de Grenoble, 38 St Martin d' Heres (France)); Sainfort, P. (CRV Pechiney, 38 Voreppe (France))

1993-11-01

265

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

International Nuclear Information System (INIS)

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

1977-01-01

266

Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate  

International Nuclear Information System (INIS)

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

2011-02-03

267

Laser welding for brazed aluminium alloy component; Aluminium gokinsei rozuke buzai no laser yosetsu  

Energy Technology Data Exchange (ETDEWEB)

An experimental discussion was given on effect of a brazing layer on porosity formation in laser welding of aluminum alloys. The experiment used a brazed member containing a brazing layer and flat aluminum alloy plates containing none whatever of brazing layer. The brazing material used BA4004 of the Al-Si system, and the filler wire used AA4043-WY. The welding was a butt welding of the flat aluminum plates by using a CO2 laser welding machine with a maximum output of 5.5 kW. A radial ray permeation test was performed to measure porosity in the weld. The following results were obtained by the experiment: the joint structure containing a brazing layer has a greater number of pores than a joint structure not containing a brazing layer; the number of pores generated in the joint structure containing a brazing layer decreased with increasing welding speed; the number has decreased to three pores per welding length of 10 mm at the speed of 20 mm/s; and the number has also decreased by removing a brazing layer at the groove locally. 14 refs., 15 figs., 3 tabs.

Aota, K.; Takenaka, T.; Ishimaru, Y.; Okamura, H. [Hitachi, Ltd., Tokyo (Japan)

1997-08-05

268

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

269

Influence of the reinforcement additions on the creep strength of dispersion strengthened aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

A comparative study of creep behaviour was conducted on eight different aluminium alloys which are strengthened by carbide and oxide dispersoids with three different volume fractions (C002, C101, C102). The matrix materials are AlSi20, AlSi20Fe5, AlMgSi1, AlSi12Fe5, AlMg1, AlMg2, Almg4 and AlCuMg1. The dispersoids were added to the matrix material powder and processed by mechanical alloying. Creep tests were carried out on cylindrical specimens at 300 C and 400 C up to fracture. These products were fabricated by cold isostatic pressing (CIP) followed by hot extrusion to improve its mechanical properties. The applied stress was chosen to have a fracture life ranging from 0.1 to 3000 hours. It was concluded that the adding of 1% carbon and 2% oxygen as a dispersioid materials in the aluminium alloy matrix has a great effect on the creep strength in comparison with the addition of the alloying elements such as Si, Mg, Cu and Fe in high percentages up to 20%. (orig.)

El-Magd, E. [Technische Hochschule Aachen (Germany). Dept. of Mater. Sci.; Ismail, Y. [Menia Univ. (Egypt). Faculty of Engineering

1997-06-01

270

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

Directory of Open Access Journals (Sweden)

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

T. Haga

2013-07-01

271

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

272

Wear Properties of Alumina Particles Reinforced Aluminium Alloy Matrix Composite  

Directory of Open Access Journals (Sweden)

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

Faiz Ahmad

2011-01-01

273

The surface tension of liquid aluminium-based alloys  

Energy Technology Data Exchange (ETDEWEB)

In a systematic study, the surface tensions of the binary alloys Al-Fe and Al-Ni were investigated over a wide temperature and concentration range using electromagnetic levitation and the oscillating drop technique. Surface tensions were derived from the oscillation frequencies applying the formalism of Cummings and Blackburn. Temperature was measured by single-color pyrometry. Of particular interest in these alloys are melts corresponding to compositions of intermetallic phases, because potential ordering phenomena may influence all thermophysical properties. In both systems, an increase of the surface tension is observed at such concentrations. On the basis of partial excess Gibbs enthalpies, surface tensions can be calculated via the Butler equation and compared with experimental results. The agreement with our experimental data depends crucially on the quality of the thermodynamic potentials used. In addition, phenomenological models are also discussed, which describe the general trend correctly.

Egry, I. [Institute for Materials Physics in Space, German Aerospace Center, DLR, 51170 Cologne (Germany)], E-mail: Ivan.Egry@dlr.de; Brillo, J.; Holland-Moritz, D. [Institute for Materials Physics in Space, German Aerospace Center, DLR, 51170 Cologne (Germany); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 8, Kyrylo and Methodiy Street, 79005 Lviv (Ukraine)

2008-11-15

274

The surface tension of liquid aluminium-based alloys  

International Nuclear Information System (INIS)

In a systematic study, the surface tensions of the binary alloys Al-Fe and Al-Ni were investigated over a wide temperature and concentration range using electromagnetic levitation and the oscillating drop technique. Surface tensions were derived from the oscillation frequencies applying the formalism of Cummings and Blackburn. Temperature was measured by single-color pyrometry. Of particular interest in these alloys are melts corresponding to compositions of intermetallic phases, because potential ordering phenomena may influence all thermophysical properties. In both systems, an increase of the surface tension is observed at such concentrations. On the basis of partial excess Gibbs enthalpies, surface tensions can be calculated via the Butler equation and compared with experimental results. The agreement with our experimental data depends crucially on the quality of the thermodynamic potentials used. In addition, phenomenological models are also discussed, which describe the general trend correctly

2008-11-15

275

Fracture behaviour of 2195-T8 aluminium alloy plates  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the determination of the fracture toughness of a thin Al-Cu-Li 2195-T8 alloy plate faces to the problems of insufficient thickness constraint and pop-ins coupled with local unstable crack growth. Since crack initiation occurs by crack tip blunting followed by ductile tearing, J{sub 1c} is an advisable alternative to K{sub 1c}. The microstructural interpretation of J{sub 1c} values indicates that they depend mainly on the inclusion distribution of the alloy, and that the local interparticle spacing along inclusion rows aligned in the rolling direction is the initiation toughness controlling parameter, irrespective of the crack orientation plane. On the other hand, crack growth toughness, expressed by the tearing modulus T, shows a crack orientation dependence, because the interparticle spacing along inclusion rows determines the T values in TL samples, whereas the spacing between inclusion rows determines the T values in LT samples. (orig.)

Doglione, R.; Mura, L.; Verniani, C.; Firrao, D. [Politecnico di Torino, Torino (Italy)

2002-07-01

276

Creep properties of 7075 aluminium alloy under intermittent stressing  

International Nuclear Information System (INIS)

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

1989-01-01

277

The fatigue response of the aluminium-lithium alloy, 8090  

Science.gov (United States)

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

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

1989-01-01

278

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

International Nuclear Information System (INIS)

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

2014-01-25

279

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-25

280

Galvanic corrosion of aluminium-copper model alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

 
 
 
 
281

Tensile behavior of dissimilar friction stir welded joints of aluminium alloys  

International Nuclear Information System (INIS)

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

2010-10-01

282

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

Energy Technology Data Exchange (ETDEWEB)

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

Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India)], E-mail: visvabalu@yahoo.com; Ravisankar, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India); Madhusudhan Reddy, G. [Metal Joining Section, Defence Metallurgical Research Laboratory (DMRL), Kanchanbag (P.O), Hyderabad 560 058 (India)

2008-07-01

283

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

International Nuclear Information System (INIS)

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

2008-01-01

284

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

2013-05-01

285

The solidification behavior of dilute aluminium-scandium alloys  

International Nuclear Information System (INIS)

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

1998-10-09

286

Anodic oxidation and dielectric behaviour of aluminium-niobium alloys  

International Nuclear Information System (INIS)

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

2006-08-01

287

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-15

288

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

International Nuclear Information System (INIS)

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

1964-01-01

289

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

International Nuclear Information System (INIS)

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

1969-01-01

290

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2006-01-01

291

High speed twin roll casting of 6016 aluminium alloy strip  

Directory of Open Access Journals (Sweden)

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

H. Sakaguchi

2007-01-01

292

Continuous roll casting of aluminium alloys – casting parameters analysis  

Directory of Open Access Journals (Sweden)

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

E. Krsti? Vukelja

2010-04-01

293

Forming a lever preform made of aluminium alloy 2014  

Directory of Open Access Journals (Sweden)

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

T. Bulzak

2014-10-01

294

The microstructure and precipitation kinetics of a cast aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-08-15

295

The microstructure and precipitation kinetics of a cast aluminium alloy  

International Nuclear Information System (INIS)

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

2006-08-01

296

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

Science.gov (United States)

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

Rittapai, Apiwat; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

2014-01-01

297

Welding procedure for aluminium alloy; Aluminium gokin no yosetsu seko gijutsu  

Energy Technology Data Exchange (ETDEWEB)

Recent trends of aluminum alloy welding technologies are described. Proper selection of welding materials for a given combination of various parent metals is discussed, and guidelines about choosing between the two arc welding methods (TIG welding, MIG welding) are described. Also discussed are the application of inverter-controlled AC/DC-switch TIG welding to the lap welding of 10mm-thick tubes for power transmission lines, application of inverter-controlled pulsed MIG welding to thin-sheet welding, application of MIG welding to approximately 1.0mm-thick sheets by the use of the cycle-pulsed welding method, improvement of welding efficiency by the use of the double-wire MIG welding method, and selective application of high-current MIG welding and ordinary MIG welding of all attitudes and narrow-groove MIG welding in the manufacture of spherical tanks for LNG carriers. In relation to laser welding, reference is made to a technique for preventing pore generation (with the laser beam oscillated in the direction of spray line) and to some notes about coagulation crack prevention. 12 refs., 12 figs., 3 tabs.

Omae, T.; Ishikawa, Y.

1997-06-01

298

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

International Nuclear Information System (INIS)

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

1995-02-01

299

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

International Nuclear Information System (INIS)

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

2007-12-12

300

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

Science.gov (United States)

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

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

2007-12-01

 
 
 
 
301

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

302

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

International Nuclear Information System (INIS)

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

2006-01-01

303

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

International Nuclear Information System (INIS)

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

2008-12-01

304

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

International Nuclear Information System (INIS)

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

2009-07-01

305

Rare earths (Y, La and Ce) effect on corrosion and mechanical properties of aluminium-manganese alloy  

International Nuclear Information System (INIS)

Effect of some rare earths (yttrium, cerium and lanthanum) on corrosion-electrochemical and mechanical properties of aluminium-manganese eutectic alloy (1.9% Mn) has been studied in neutral medium. It is established that free corrosion potentials of the Al-Mn (1.9%)-Y (La, Ce) system are located in the field of passivation. Rare earth (Y, La, Ce) doping of aluminium-manganese eutectics leads to the displacement of free corrosion potentials and pitting-formation in the range of more positive values. Optimum content of rare earths for the reach of higher corrosion resistance in the eutectic aluminium-manganese alloy is amount 0.01-0.05%. Alloys with the mention content have been recommended as corrosion-resisting materials for mediums lead to pitting corrosion. Role of rare earths (Y, La and Ce) as doping components to aluminium alloys comes to their modifying effect on the structure that allows to receive constructional material on the basis of aluminium with higher corrosion resistance

2008-10-01

306

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

Energy Technology Data Exchange (ETDEWEB)

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

Tanem, Bjorn S. [SINTEF Materials and Chemistry, Hogskoleringen 5, NO-7465 Trondheim (Norway)]. E-mail: bjorn.s.tanem@sintef.no; Svenningsen, Gaute [Department of Materials Technology, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)]. E-mail: gaute.svenningsen@material.ntnu.no; Mardalen, Jostein [SINTEF Materials and Chemistry, Hogskoleringen 5, NO-7465 Trondheim (Norway)]. E-mail: jostein.mardalen@sintef.no

2005-06-01

307

Bond strength of pressure sensitive adhesives for CFRP aluminium-alloy hybrid beams under impact loading  

Science.gov (United States)

This paper discusses the impact absorbing capabilities of CFRP aluminium-alloy hybrid beams bonded with double-coated pressure sensitive adhesive tapes. Two sorts of double-coated adhesive tapes (VHB and SBT, 3M) were used in experiments. The strength and absorbed energy of the beams under impact loading were measured using an instrumented Charpy tester. Using the beams having the different adhesive tapes and the CFRP of different length, the variations of the strength and the absorbed energy were investigated. The beams bonded with VHB showed sufficient strength and absorbed energy. SBT showed also great capability of absorbing impact energy.

Sato, C.

2003-09-01

308

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

Directory of Open Access Journals (Sweden)

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

N. FATCHURROHMAN

2012-04-01

309

Parametric study of friction stir spot welding of aluminium alloy 5754  

Directory of Open Access Journals (Sweden)

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

D. Klob?ar

2014-01-01

310

Measurement of spall strength of aluminium alloy, Al2024-T4  

International Nuclear Information System (INIS)

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

2007-12-27

311

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2000-01-01

312

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

International Nuclear Information System (INIS)

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

1993-01-01

313

Powder metallurgy route in production of aluminium alloy matrix particulate composites  

International Nuclear Information System (INIS)

Metal matrix composites based on an aluminium alloys were produced by powder metallurgy route, involved unidirectionally hot pressing under 500 MPa for 15 minutes at temperature about 0.95 Ts [Solidus Temperature]. Metal matrix contains different weight percents of SiC, ?Al2O3, WC and Si3N4 with different particle size. Wear and mechanical tests have been carried out on composites, and it was found that about 90% of wear reduction occured in composite with 30% SiC compared with pressed matrix. (orig.)

1993-11-01

314

Powder metallurgy route in production of aluminium alloy matrix particulate composites  

Energy Technology Data Exchange (ETDEWEB)

Metal matrix composites based on an aluminium alloys were produced by powder metallurgy route, involved unidirectionally hot pressing under 500 MPa for 15 minutes at temperature about 0.95 Ts [Solidus Temperature]. Metal matrix contains different weight percents of SiC, [alpha]Al[sub 2]O[sub 3], WC and Si[sub 3]N[sub 4] with different particle size. Wear and mechanical tests have been carried out on composites, and it was found that about 90% of wear reduction occured in composite with 30% SiC compared with pressed matrix. (orig.).

Al-Rashed, A. (Inst. of Chemical Technology Prague, Prague (Czech Republic)); Holecek, S. (Inst. of Chemical Technology Prague, Prague (Czech Republic)); Prazak, M. (Inst. of Chemical Technology Prague, Prague (Czech Republic)); Procio, M. (Inst. of Chemical Technology Prague, Prague (Czech Republic))

1993-11-01

315

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-03-15

316

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mechanical properties in tension of two aluminium alloys (AA5059-H131 and AA7039-T651) used in armour applications were determined from tests carried out over a wide range of strain-rates on round specimens. The experimental research was developed in the DynaMat laboratory of the University of Applied Sciences of Southern Switzerland. The target strain rates were set at the following four levels: 10?3, 30, 300 and 1000s?1. The quasi-static tests were performed with a universal electro...

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

2012-01-01

317

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

International Nuclear Information System (INIS)

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

2005-10-01

318

Powder metallurgy route in production of aluminium alloy matrix particulate composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Meta1 matrix composites based on an aluminium alloys were produced by powder metallurgy route, involved unidirectionally hot pressing under 500 MPa for 15 minutes at temperature about 0.95 Ts [Solidus Temperature]. Metal matrix contains different weight percents of SiC, ?Al2O3, WC and Si3N4 with different particle size. Wear and mechanical tests have been carried out on composites, and it was found that about 90% of wear reduction occured in composite with 30% SiC compared with pressed matrix.

Al-rashed, A.; Holecek, S.; Praza?k, M.; Procio, M.

1993-01-01

319

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

2002-12-01

320

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

Directory of Open Access Journals (Sweden)

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

K. Mroczka

2008-10-01

 
 
 
 
321

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

Directory of Open Access Journals (Sweden)

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

D. Džuni?

2012-12-01

322

Machinability of magnesium and aluminium alloys. Part I: cutting resistance; Usinabilite des alliages de magnesium et d'aluminium. Partie I: Forces de coupe  

Energy Technology Data Exchange (ETDEWEB)

Aluminium (2.7 g/cm{sup 3}) and magnesium (1.7 g/cm{sup 3}) are two competing light metals with similar mechanical properties and excellent possibilities for recycling. The forming of magnesium is often seen as an impediment to its use. New forming techniques using magnesium shavings are being developed, particularly in Japan. The machining of magnesium alloys by removal of metal raises safety concerns (risk of fire), which limits many potential applications of magnesium. The purpose of this work is to clarify and compare the machining properties of these two types of metal and better understand the mechanisms that may explain the differences in behaviour. Such a comparison could eventually provide an estimate of the cost of producing shavings for the manufacture of aluminium and magnesium parts through forging and extrusion, which would limit environmental pollution. Based on an analysis of cutting resistance during machining, it was demonstrated that magnesium alloys are easier to machine than similar aluminium alloys. Magnesium shavings are shorter than those of 6061-T6, but are especially more regular than those of A356, and their size is independent of cutting speed. It was also demonstrated that the fragility of materials can be characterized based on the results of cutting resistance produced during drilling.

Balout, B.; Songmene, V.; Masounave, J. [Ecole de technologie superieure (ETS), Genie mecanique, Montreal, Quebec (Canada)]. E-mail: v.songmene@mec.etsmtl.ca

2002-07-01

323

The role of strontium in modifying aluminium–silicon alloys  

International Nuclear Information System (INIS)

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

2012-05-01

324

In situ creep under helium implantation of titanium aluminium alloy  

Science.gov (United States)

The intermetallic alloy Ti-47Al-2W-0.5Si (at.%) has been homogeneously implanted with 4He 2+ ions under uniaxial tensile stresses from 20 to 450 MPa to a maximum dose of about 0.16 dpa (1370 appm-He) with displacement damage rates of 2 × 10 -6 dpa s -1 at temperatures of 573 and 773 K. Strain under implantation was determined by Linear Variable Displacement Transformer (LVDT), while changes of microstructure were investigated after implantation by Transmission Electron Microscopy (TEM). Irradiation creep strain showed a pronounced transient behaviour, virtually independent of temperature, with a stress dependence which can be approximately described by a creep compliance of 8 × 10 -6 dpa -1 MPa -1 up to stresses of 350 MPa. The microstructure of the as-received material consisted of a patch-work of mainly lamellar ?/ ?2 colonies and equiaxed ?-grains with islands of precipitates. Only 'black dot' damage was observed after implantation at 573 K under different stresses, while implantation at 773 K yielded a dense population of bubbles and dislocation loops, mostly mutually attached.

Chen, J.; Jung, P.; Nazmy, M.; Hoffelner, W.

2006-06-01

325

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

Science.gov (United States)

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

Rabah, Mahmoud A

2003-01-01

326

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

International Nuclear Information System (INIS)

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

2003-06-01

327

Decomposition in aluminium alloys: diffuse scattering and crystal modelling  

International Nuclear Information System (INIS)

In the present study the microstructure of metastable precipitates in Al-Ag and Al-Cu, so called pre-precipitates or Guinier-Preston (GP) zones, was investigated. In both systems important aspects of the microstructure are still controversially discussed. In Al-Ag two forms of GP zones are suggested; depending on the aging temperatures above or below about 443 K, ?- or ?-zones should evolve. Differences between these two types of zones may be due to differences in internal order and/or composition. In Al-Cu the characterization of GP I zones is difficult because of the strong atomic displacements around the zones. The proper separation of short-range order and displacement scattering within a diffuse scattering experiment is still under discussion. The technique used to determine the short-range order in both alloys was diffuse scattering with neutrons and X-rays. To separate short-range order and displacement scattering, the methods of Georgopoulos-Cohen (X-ray scattering) and Borie-Sparks (neutron scattering) were used. Of main importance is the optimization of the scattering contrast and thus the scattering contribution due to short-range order. Short-range order scattering is rationalized in terms of pair correlations. Crystals may subsequently be modelled to visualize the microstructure. The Al-Ag system was investigated by diffuse X-ray wide-angle scattering and small-angle neutron scattering. The small-angle neutron scattering measurement was necessary since the GP zones in Al-Ag are almost spherical and the main scattering contribution is found close to the origin of reciprocal space. The small-angle scattering is not that important in the case of Al-Cu because the main scattering extends along (100) owing to the planar character of the GP I zones on (100) lattice planes. (author) 24 figs., 10 tabs., refs

1995-01-01

328

Decomposition in aluminium alloys: diffuse scattering and crystal modelling  

International Nuclear Information System (INIS)

In the present study the microstructure of metastable precipitates in Al-Ag and Al-Cu, so called pre-precipitates or Guinier-Preston (GP) zones, was investigated. In both systems important aspects of the microstructure are still controversially discussed. In Al-Ag two forms of GP zones are suggested; depending on the aging temperature above or below about 443 K, ? or ?-zones should evolve. Differences between these two types of zones may be due to differences in internal order and/or composition. In Al-Cu the characterization of GP I zones is difficult because of the strong atomic displacements around the zones. The proper separation of short-range order and displacement scattering within a diffuse scattering experiment is still under discussion. The techniques used to determine the short-range order in both alloys was diffuse scattering with neutrons and X-rays. To separate short-range order and displacement scattering, the methods of Georgopoulos-Cohen (X-ray scattering) and Borie-Sparks (neutron scattering) were used. Of main importance is the optimization of the scattering contrast and thus the scattering contribution due to short-range order. Short-range order scattering is rationalized in terms of pair correlations. Crystals may subsequently be modelled to visualize the microstructure. The Al-Ag system was investigated by diffuse X-ray wide-angle scattering and small-angle neutron scattering. The small-angle neutron scattering measurement was necessary since the GP zones in Al-Ag are almost spherical and the main scattering contribution is found close to the origin of reciprocal space. The small-angle scattering is not that important in the case of Al-Cu because the main scattering extends along owing to the planar character of the GP I zones on (100) lattice planes. This morphology is due to the large difference in size between Al and Cu atoms. (author) 24 figs., tabs., refs

1995-01-01

329

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

International Nuclear Information System (INIS)

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

2011-12-01

330

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

331

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

International Nuclear Information System (INIS)

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

2011-09-01

332

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

International Nuclear Information System (INIS)

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

1998-01-01

333

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

334

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

Energy Technology Data Exchange (ETDEWEB)

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.

Senthil Kumar, T. [Department of Automobile Technology, School of Engineering and Technology. Bharathidasan University, Tiruchirappalli - 620 024, Tamil Nadu (India); Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalainagar - 608 002, Tamil Nadu (India)]. E-mail: visvabalu@yahoo.com; Sanavullah, M.Y. [V.M.K.V. Engineering College, Salem - 636 308, Tamil Nadu (India)

2007-07-01

335

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

Directory of Open Access Journals (Sweden)

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

Olugbenga A. Omotosho

2012-04-01

336

The study of aluminium rich alloys of the ternary systemaluminium-strontium-silicon  

International Nuclear Information System (INIS)

The purpose of present work is investigations in the area of solidsolution on the base of aluminium and construction of surface of liquidusadjoining to the vertex of aluminium angle of the system ofstrontium-aluminium-silicon

1976-01-01

337

The use of sodium {beta}-alumina for controlling the rate of sodium addition to aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Sodium, when added at concentrations of 30-200 ppm, can be used to modify the microstructure and properties of a number of aluminium alloys. This has traditionally been achieved by physically adding a sodium rich alloy or flux to the melt. However, this method suffers from considerable inefficiency since much of the sodium burns or evaporates on the surface of the metal generating fumes and dross. A much cleaner and more efficient process is under development using a sodium ion conducting solid electrolyte to separate a source of sodium from the molten aluminium alloy. Under the influence of an applied potential, sodium is transported through the solid electrolyte with the rate of sodium addition to the melt controlled by the current flow. An additional advantage of using an electrochemical sodium addition method is that it lends itself to control via a solid state sodium sensor. This can be used to continuously measure changes in sodium activity in the alloy leading to improved process control. In practice, this system gives a much greater level of control over the rate of sodium addition and because the additions are made continuously within the molten metal, dross and fumes are virtually eliminated from the process. Experiments have been performed in laboratory, intermediate and industrial environments and this has been shown to be a viable method of controlling the sodium content of aluminium alloys at industrial scales. Small portions of solid electrolyte have been shown capable of withstanding a current density in excess of 1.3 A cm{sup -2}. A standard 200x30 mm electrolyte tube has been operated at a current density of approximately 0.6 A cm{sup -2}, supplying sodium at a rate of 1.8 g min{sup -1} to a launder of aluminium. This rate of addition from a single tube is able to continuously supply the desired quantity of sodium to two tonnes per hour of aluminium alloy. (Abstract Truncated)

Doughty, G.; Fray, D.J. [Department of Mining and Mineral Engineering, Leeds University, Leeds (United Kingdom); Van Der Poorten, C.; DeKeyser, J. [VITO, Energy Division, Mol (Belgium)

1996-07-20

338

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

339

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

International Nuclear Information System (INIS)

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

1996-02-02

340

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 -20 °C. The combination of scanning electron microscopy, secondary ion mass spectrometry and KFM demonstrated that the grain and subgrain boundaries were preferential pathways for the short-circu...

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

2013-01-01

 
 
 
 
341

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

342

Application of Regenerative Ceramic Burners on an Aluminium Bulk Melting Furnace. A Demonstration at Alcan Enfield Alloys Ltd. Final Report.  

Science.gov (United States)

A report is given of a project involving the installation of a pair of regenerative ceramic burners in place of conventional natural gas burners on a 40-tonne forewell aluminium melting furnace at the Bradford plant of Alcan Enfield Alloys Ltd. The result...

1986-01-01

343

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

International Nuclear Information System (INIS)

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

2009-09-06

344

Microstructure and mechanical properties of C355.0 cast aluminium alloy  

Directory of Open Access Journals (Sweden)

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

J. Sieniawski

2011-02-01

345

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

International Nuclear Information System (INIS)

Highlights: · A new silanol-based hybrid coating has been synthesized. · The incorporation of CeO2 and ZrO2 nanoparticles into the coating greatly improves the corrosion resistance of the coated aluminium alloy. · The effectiveness of the coating is increasingly evident for long term exposure to the sodium chloride solution. · The silanol-based nanocomposite coatings have self-healing ability. - Abstract: A new hybrid sol-gel type film, composed of tetraethylorthosilicate (TEOS) and tetraocthylorthosilicate (TEOCS), and modified with different nanoparticle systems, has been investigated as a coating for protection of AA-2024-T3 aluminium alloy. The nanoparticle systems considered were either ZrO2 or CeO2 or their combination. The zirconia nanoparticles were prepared from a Zr (IV) propoxide sol (TPOZ), using an organic stabilizer, and the CeO2 nanoparticles were developed spontaneously after adding cerium nitrate solution to the hybrid sol. The chemical composition and the structure of the hybrid sol-gel films were examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion resistance of the coated AA-2024 alloy was examined by potentiodynamic polarization. The results revealed that, for short exposure times in the electrolyte, incorporation of ZrO2 or CeO2 nanoparticles in the hybrid film does not 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

346

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-09-01

347

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

Directory of Open Access Journals (Sweden)

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

M. Thirumal Azhagan

2014-03-01

348

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

349

Aluminium alloy selection for use as structural material in research reactors  

International Nuclear Information System (INIS)

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

2010-06-14

350

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

International Nuclear Information System (INIS)

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

1981-01-01

351

Electrochemical reactivity of laser-machined microcavities on anodised aluminium alloys  

International Nuclear Information System (INIS)

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

2003-09-30

352

Electrochemical reactivity of laser-machined microcavities on anodised aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

Kautek, Wolfgang; Daminelli, Grazia

2003-09-30

353

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

International Nuclear Information System (INIS)

This paper presents the results of a cooperative study between AEROSPATIALE, DASSAULT AVIATION, BRITISH AEROSPACE, ALENIA, IMPERIAL COLLEGE, CEREM, ALPOCO, RAUFOSS A/S, CENIM AND THE UNIVERSITY OF PISA supported by the CEC under BRITE EURAM contract BREU 0356 C which aims at developping a new Aluminium alloy for use at 250 - 300 C by Rapid Solidification / Powder Metallurgy technology. Tensile and creep properties at temperatures up to 350 C, fracture toughness and corrosion results on 11 alloys from the Al-Fe-V, Al-Fe-Mo, Al-Cr-Ni and Al-Mn-Ni systems are presented and discussed. Their stability for long exposures at temperatures up to 350 C is demonstrated on the basis of fine microstructural investigations and mechanical tests. The cross effect of the Iron content and the powder size distribution is detailed in the case of the gas atomization process for the Al-Fe-V system. The results obtained on the most promising products are detailed and compared to those available on existing 8009 and 8019 alloys. Potential applications on aerospace structures are described. (orig.)

1993-11-01

354

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

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a cooperative study between AEROSPATIALE, DASSAULT AVIATION, BRITISH AEROSPACE, ALENIA, IMPERIAL COLLEGE, CEREM, ALPOCO, RAUFOSS A/S, CENIM AND THE UNIVERSITY OF PISA supported by the CEC under BRITE EURAM contract BREU 0356 C which aims at developping a new Aluminium alloy for use at 250 - 300 C by Rapid Solidification / Powder Metallurgy technology. Tensile and creep properties at temperatures up to 350 C, fracture toughness and corrosion results on 11 alloys from the Al-Fe-V, Al-Fe-Mo, Al-Cr-Ni and Al-Mn-Ni systems are presented and discussed. Their stability for long exposures at temperatures up to 350 C is demonstrated on the basis of fine microstructural investigations and mechanical tests. The cross effect of the Iron content and the powder size distribution is detailed in the case of the gas atomization process for the Al-Fe-V system. The results obtained on the most promising products are detailed and compared to those available on existing 8009 and 8019 alloys. Potential applications on aerospace structures are described. (orig.).

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

1993-11-01

355

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

International Nuclear Information System (INIS)

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

2014-03-01

356

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

Science.gov (United States)

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

Cabibbo, Marcello

2013-09-01

357

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

358

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

2006-10-01

359

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

360

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

International Nuclear Information System (INIS)

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

2010-02-18

 
 
 
 
361

The deformation characteristics of SiC particulate-reinforced aluminium alloy 6061  

Energy Technology Data Exchange (ETDEWEB)

The deformation characteristics of aluminium alloy 6061 reinforced with particulate SiC have been investigated using experimental and numerical methods. The materials investigated contained 0, 5, 10, 20% by volume and 3, 10, 30{mu}m by size of SiC particulates. The matrix microstructure was systematically heat treated to natural aged (NA), peak aged (PA) and over-aged (OA) conditions. In order to set up a comparative materials database, the microstructural characteristics of the unreinforced matrix material with identical fabricating and processing history were examined. The tensile strength and stiffness of the composites increased with increasing particle volume fraction for heat treatments provided that it was over a limiting value. The PA specimens had the highest tensile strength, but the NA specimens had the greatest elongation to failure and the largest ratio of tensile to yield strength. Good agreement was obtained between experimental results and model predictions of mechanical properties. ((orig.))

Shyong, J.H. [Oxford Univ. (United Kingdom). Dept. of Materials; Derby, B. [Oxford Univ. (United Kingdom). Dept. of Materials

1995-06-30

362

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2011-02-15

363

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

International Nuclear Information System (INIS)

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

2009-11-03

364

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

International Nuclear Information System (INIS)

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.

2011-02-01

365

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

Directory of Open Access Journals (Sweden)

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

F.V. Díaz

2012-08-01

366

Improved material properties for cast aluminium alloys : from the processes to life prediction modelling  

Energy Technology Data Exchange (ETDEWEB)

Microstructure evolution and loss in mechanical properties due to ageing, in cast aluminium alloys used by different manufacturers for cylinder-heads with various initial heat treatments and amount of copper was studied. Two have been chosen as references, namely AS7U3G T5 (ASTM319) and AS7G03 T7 (ASTM356). They were subjected to different heat treatments, from the as-received state to saturated ageing state and studied in fatigue, with hardness evolution and by TEM image analysis. After numerical identification, a link was established between microstructural evolutions and phenomenological modelling. Ultimately, the objective of this approach is to build a descriptive model for life prediction and behaviour of the cylinder head as a function of the chemical composition and heat treatments. (orig.)

Guillot, I.; Ovono-Ovouo, D. [Univ. de Technologie de Co. - Lab. Roberval - UMR CNRS 6066, Centre de Recherches de Royallieu - Co. (France); Massinon, D. [Fonderies Montupet - Nogent-sur-Oise (France); Barlas, B. [Centre des Materiaux de l' Ecole Nationale Superieure des Mines de Paris - Evry (France)

2003-07-01

367

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.

Bianchi S.

2012-08-01

368

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

369

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-07-01

370

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

Scientific Electronic Library Online (English)

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

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

371

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

372

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

2006-01-01

373

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

374

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

International Nuclear Information System (INIS)

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

2007-04-07

375

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-20

376

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

377

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

Directory of Open Access Journals (Sweden)

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

G. Venkatasubramanian

2013-03-01

378

Effects of homogenisation treatment on microstructure and hot ductility of aluminium alloy 6063  

Energy Technology Data Exchange (ETDEWEB)

Several homogenisation treatments were applied to direct chill (DC) cast ingots of aluminium alloy 6063, in order to analyse the resulting microstructures developed from these diverse conditions and their effects on the hot ductility of this alloy. Imaging was performed using scanning electron microscopy (SEM) and a focused ion beam (FIB) instrument. These techniques identified variations in distribution and morphology of second phase particles (AlFeSi and Mg{sub 2}Si). FIB results for the various AlFeSi particles correctly identify their shapes in three dimensions (3D). The particles were identified by energy dispersive spectroscopy (EDS) in the SEM, and by X-ray diffraction (XRD) for bulk samples. Hot tensile testing (HTT) was conducted between 470 and 600 deg C to asses the hot ductility for each condition. The inferior ductility of as cast samples was due to the poor bond strength of the {beta} AlFeSi phase at the grain boundaries. Homogenised samples, which contain {alpha} AlFeSi, exhibited improved ductility. Samples that were water quenched following homogenisation were absent of Mg{sub 2}Si precipitates, when these elements remained in solid solution. These exhibited the highest ductility. (Author)

Couto, K.B.S.; Claves, S.R.; Geetruyden, W.H. van; Misiolek, W.Z.; Goncalves, M.

2005-02-15

379

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

380

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-01-15

 
 
 
 
381

Micromechanical aspects of fatigue in a MIG welded aluminium airframe alloy  

Energy Technology Data Exchange (ETDEWEB)

Fusion welding of high strength aluminium alloys is being widely considered within the commercial aircraft industry as an alternative to established mechanical fastening methods. The objective of the present article is to characterise the microstructural features of metal inert gas (MIG) welded plate of the conventional damage tolerant alloy, 2024-T351. Micromechanical aspects of the fatigue performance of this welded material are then addressed in a companion article. The general microstructure of the MIG weld was studied using optical microscopy and scanning electron microscopy, in association with electron back-scattered diffraction mapping. Columnar dendritic structures at the edge of the fusion zone are seen, with fairly uniform equiaxed dendritic grain structure dominating in the weld centre. Local microstructural conditions of the different elements of the weld have been assessed via micro-hardness and differential scanning calorimetry, identifying the balance between aging, overaging, re-solutionising and re-precipitation occurring across the weld region. Residual stress measurements by laboratory X-ray and synchrotron X-ray diffraction are also discussed, showing stress relaxation and redistribution occurring under loads representative of smooth specimen fatigue testing. The fusion zone is seen to present a tensile residual stress field, with peak longitudinal stress occurring towards the interface with the fusion zone.

Lefebvre, F. [Materials Research Group, School of Engineering Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ (United Kingdom)]. E-mail: fabien.lefebvre@insa-lyon.fr; Ganguly, S. [Department of Materials Engineering, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Sinclair, I. [Materials Research Group, School of Engineering Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ (United Kingdom)

2005-04-25

382

Laser welding of aluminium alloys 5083 and 6082 under conduction regime  

Science.gov (United States)

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

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

2009-09-01

383

Micromechanical aspects of fatigue in a MIG welded aluminium airframe alloy  

International Nuclear Information System (INIS)

Fusion welding of high strength aluminium alloys is being widely considered within the commercial aircraft industry as an alternative to established mechanical fastening methods. The objective of the present article is to characterise the microstructural features of metal inert gas (MIG) welded plate of the conventional damage tolerant alloy, 2024-T351. Micromechanical aspects of the fatigue performance of this welded material are then addressed in a companion article. The general microstructure of the MIG weld was studied using optical microscopy and scanning electron microscopy, in association with electron back-scattered diffraction mapping. Columnar dendritic structures at the edge of the fusion zone are seen, with fairly uniform equiaxed dendritic grain structure dominating in the weld centre. Local microstructural conditions of the different elements of the weld have been assessed via micro-hardness and differential scanning calorimetry, identifying the balance between aging, overaging, re-solutionising and re-precipitation occurring across the weld region. Residual stress measurements by laboratory X-ray and synchrotron X-ray diffraction are also discussed, showing stress relaxation and redistribution occurring under loads representative of smooth specimen fatigue testing. The fusion zone is seen to present a tensile residual stress field, with peak longitudinal stress occurring towards the interface with the fusion zone

2005-04-25

384

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

385

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

Science.gov (United States)

The influence of modifier and grain refiner on the nucleation process of a commercial hypoeutectic Al-Si foundry alloy (A356) was investigated using optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis technique (EPMA). Filtering was used to improve the casting quality; however, it compromised the modification of silicon. Effect of filtering on strontium loss was also studied using the afore-mentioned techniques. EPMA was used to trace the modifying and grain refining agents inside matrix and eutectic Si. This was to help understanding mechanisms of nucleation and modification in this alloy. Using EPMA, the negative interaction of Sr and Al3TiB was closely examined. In modified structure, it was found that the maximum point of Sr concentration was in line with peak of silicon; however, in case of just 0.1wt% added Ti, the peak of Ti concentration was not in line with aluminium, (but it was close to Si peak). Furthermore, EPMA results showed that using filter during casting process lowered the strontium content, although produced a cleaner melt. PMID:20494588

Faraji, M; Katgerman, L

2010-08-01

386

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

International Nuclear Information System (INIS)

In the present work, the effects of heat treatments on mechanical properties, microstructure evolution and damage resulting from plastic deformation of thixoformed A319 and A356 aluminium alloys, are studied. The thixoforming process can lead to the production of components that are characterized by very good mechanical properties and low porosity with a globular microstructure which is fine and uniform. The mechanical properties can be further improved through heat treatments such as T5 and T6. The prime factor influencing the damage in the alloys belonging to the Al-Si system is represented by decohesion of silicon particles resulting from the stress concentration at the particle-matrix interfaces. A statistical analysis of fractured particles after tensile tests in the as-cast and as-treated condition has been carried out in the present work; optical and scanning electron microscopy techniques have been used to characterize the microstructure and fracture surfaces of the specimens and the results are fully presented

2005-07-01

387

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

International Nuclear Information System (INIS)

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

1998-01-01

388

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

2014-01-01

389

Microstructure characterization of titanium-base aluminium alloys by X-ray diffraction using Warren-Averbach and Rietveld method  

International Nuclear Information System (INIS)

Present study considers microstructural characterization of titanium-base aluminium (Ti-Al) alloys, which are widely used in the aviation industry due to its excellent combination of strength and ductility. The microstructural parameters like domain size, microstrain within the domain, dislocation density and stacking fault probabilities have been evaluated in hexagonal Ti-Al alloys having four different nominal compositions in at.% by X-ray diffraction Fourier line profile analysis using Warren-Averbach and Rietveld method taking silicon as standard. This analysis shows that the deformation growth faults ? are totally absent in this hexagonal system, because it has been observed to be either negligibly small (within experimental error) or negative. This analysis also reveals that the tendency for deformation faulting ? increases by the addition of aluminium as solute and hence lowers its stacking fault energy

2008-04-03

390

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

Directory of Open Access Journals (Sweden)

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

D. Kuc

2012-03-01

391

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

392

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

393

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

394

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

Directory of Open Access Journals (Sweden)

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

A. Nagel

2007-10-01

395

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

International Nuclear Information System (INIS)

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

2008-01-01

396

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

1993-01-01

397

Age-hardening characteristics of [delta]-alumina fibre reinforced aluminium-silicon LM-13 alloy metal matrix composites  

Energy Technology Data Exchange (ETDEWEB)

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

Akbulut, H. (Univ. of Sakarya, Adapazan (Turkey)); Durman, M. (Univ. of Sakarya, Adapazan (Turkey)); Yilmaz, F. (Univ. of Sakarya, Adapazan (Turkey))

1993-11-01

398

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

International Nuclear Information System (INIS)

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

1993-11-01

399

Electrochemical impedance spectroscopy study of the behaviour of lanthanide-rich films formed on aluminium-magnesium alloys  

Energy Technology Data Exchange (ETDEWEB)

The film covering formed on AA5083 aluminium-magnesium alloy by immersion treatments in solutions containing CeCl{sub 3} has been characterized by means of electrochemical techniques. The measurement of linear polarization has enabled to establish that the treatments applied provide efficient protection against both uniform and pitting corrosion of alloy AA5083, used in shipbuilding, in solutions of NaCl. This study has been focused on the use of electrochemical impedance spectroscopy as a characterization technique for these film coverings. (orig.) 20 refs.

Aballe, A.; Bethencourt, M.; Botana, F.J.; Perez, J.; Rodriguez-Chacon, M.A. [Cadiz Univ. (Spain). Dept. de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica; Marcos, M.

1998-12-31

400