WorldWideScience
1

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

International Nuclear Information System (INIS)

The development of through-thickness texture gradient during continuous cast (CC) processing of AA 5052 aluminum alloy was investigated by X-ray diffraction. The CC slab and the hot bands after each of three rolling passes were obtained from an industrial CC processing operation. The results show that a through-thickness texture gradient exists near the surface after the first pass. The subsurface layer exhibits a very weak texture, while the center layer shows the ? fiber rolling texture. After the third pass, a strong ? fiber rolling texture is obtained at different through-thickness layers. The roll-gap geometry does not produce any shear deformation at the intermediate layer. After recrystallization annealing, the through-thickness texture gradient still exists in the AA 5052 aluminum alloy sheets. As the measured position moves towards the center from the surface, the cube recrystallization texture strengthens

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

International Nuclear Information System (INIS)

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

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

International Nuclear Information System (INIS)

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

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

International Nuclear Information System (INIS)

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

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

International Nuclear Information System (INIS)

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

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Corrosion Behaviors of Nd: YAG Laser-Gma Hybrid Weldment of AA5052-H32 al Alloys  

Science.gov (United States)

This paper investigated the corrosion behaviors of the Nd: YAG laser-gas metal arc (GMA) AA5052-H32 weldments comparing with the base alloy. The corrosion susceptibility of weldments was higher than that of the base alloy. The weld fusion zone (WFZ) suffered the severe pitting in acidic chloride media. The zones adjacent to the weld fusion boundary showed less corrosion tendency. A corrosion cracking was associated with pitting in the weldments. The surface morphology observation and composition analysis were investigated by the scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) spectroscopy. At the WFZ/HAZ interface and the HAZ/base alloy interface, the galvanic corrosion coupling existed. From the comparison, the WFZ showed anodic behavior, the zone adjacent to the weld fusion boundary showed cathodic behavior. The corrosion of WFZ was progressed by the formation of the galvanic couples.

Zhang, Da-Quan; Park, Young Woo; Lee, Kang Yong

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

International Nuclear Information System (INIS)

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

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

Scientific Electronic Library Online (English)

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

Tiago Valdameri, Capelari; José Antônio Esmerio, Mazzaferro.

2009-09-01

9

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

10

Soldering of aluminium alloys  

International Nuclear Information System (INIS)

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

11

Inhibition properties and adsorption behavior of imidazole and 2-phenyl-2-imidazoline on AA5052 in 1.0 M HCl solution  

International Nuclear Information System (INIS)

Highlights: • IM and 2-PI show corrosion inhibition for AA5052 in HCl solution. • Synergistic effect between IM and 2-PI is observed and its mechanism is assumed. • Adsorption properties are estimated using ?Gads0, ?Hads0 and Ea, respectively. • Adsorption structures and inhibition mechanism for AA5052 are proposed. - Abstract: The inhibition behavior of imidazole (IM) and 2-phenyl-2-imidazoline (2-PI) for AA5052 was investigated by weight loss, electrochemical, contact angle measurements and scanning electron microscopy. The results show that IM and 2-PI can inhibit the corrosion of AA5052 and the inhibition efficiency of 2-PI is higher. The adsorption properties of them are estimated using ?Gads0, ?Hads0 and Ea. The results reveal that the adsorption processes are exothermic reactions mainly by a monolayer chemisorption mechanism, and follow Langmuir adsorption isotherm. The differences of the monolayer adsorption structure between IM and 2-PI on AA5052 surface are analyzed, and the inhibition mechanisms are proposed

12

Recent developments in advanced aircraft aluminium alloys  

International Nuclear Information System (INIS)

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

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Investigation & Analysis of Different Aluminium Alloys t  

OpenAIRE

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

Nibedita Sethi*¹,; , Ajit Senapati²

2014-01-01

14

Heat resistant cast aluminium alloys with iron  

International Nuclear Information System (INIS)

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

15

Interaction of aluminium-berylium alloy, alloyed by cerium with oxygen of gas phase  

International Nuclear Information System (INIS)

The interaction of aluminium-berylium alloy, alloyed by cerium with oxygen of gas phase is investigated in this article. It is found that aluminium-berylium alloy, alloyed by cerium has an increased resistance to oxidation.

16

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

17

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

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Intermetallic phase particles in 6082 aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In the technical 6xxx Al alloys besides the intentional additions Mg i Si, transition metals andimpurities (Fe and Mn are always present. Even not large amount of these impurities causes the formation a newphase components. The exact composition of the alloy and casting condition will directly influence the selectionand volume fraction of intermetallic phases. During casting of 6xxx alloys, a wide variety of Fe-containingintermetallics phases Al-Fe, Al-Fe-Si and Al-Fe-Mn-Si are formed among the aluminium dendrites. The aim ofthis work was to examine the composition and morphology of complex microstructure of the intermetallics in6082 aluminium alloy.Design/methodology/approach: Light microscopy (LM, electron microscopy techniques (SEM and TEMin combination with X-ray analysis (SEM/EDS, and X-ray diffraction (XRD were used.Findings: The examinations of the as-cast alloy after slow solidification at a cooling rate 2°C/min reveal that themicrostructure consisted a wide range of intermetallics phases, namely: ß-Al5FeSi, ?-Al15(FeMn3Si, Al9Mn3Si,?-Al12Fe3Si, Mg2Si.Research limitations/implications: To facilitate confirmation of the achieved results it is recommended toexecute supplementary analysis of the aluminium alloys, 6xxx series in particular.Practical implications: Since the, what involves changes of alloy properties, From a practical position it isimportant to understand formation conditions of the intermetallics in order to control final components of thealloy microstructure. The importance of this is due to the fact that morphology, crystallography and chemicalcomposition of the intermetallics strongly affect the properties of the alloy.Originality/value: This work has provided essential data about almost all possible intermetallic phasesprecipitating in 6000 series aluminium alloys.

M. Wierzbiñska

2007-02-01

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TEM microstructure investigations of aluminium alloys used for laser alloying  

OpenAIRE

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

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

2012-01-01

20

Hot workability of the 2618 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

The hot working behaviour of a 2618 aluminium alloy was investigated in torsion at temperatures ranging from 200 to 500 C. The peak flow stress was related to temperature and strain rate by means of the conventional constitutive equations normally used for high temperature deformation of metals. On the basis of a preliminary investigation on the heat treatment response of the alloy, a subsequent study on the warm working of the material in the solution treated condition was carried out. Comparison between the results obtained at temperatures of 200 and 300 C indicated that deformation of the solution treated alloy resulted in an increase flow stress and in a reduced ductility. (orig.)

Spigarelli, S.; Bardi, F.; Evangelista, E. [Ancona Univ. (Italy). Dipt. di Meccanica

2000-07-01

21

Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys  

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Yuksel, Serkan

2013-01-01

22

Thermophysical properties of cast aluminium alloys  

OpenAIRE

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

Mazzarini, Nicolo

2014-01-01

23

Fluidity of Aluminium Foundry Alloys  

OpenAIRE

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

24

Aluminium based resistance alloys for low temperatures  

International Nuclear Information System (INIS)

The resistivity of several (AlMgMn)-alloys with a magnesium mass content of 5% and manganese contents of 0% up to 1%, has been measured in the temperature range of 1.5 to 4.2 K. It is shown that a Mn concentration of 0.078% produces a broad resistivity minimum at about 4.2 K; this means that the resistivity only varies by about 1.3ppm between 1.5 and 4.2 K. It is further shown that the technical aluminium alloy AlMg 5 also has a similar small temperature coefficient of resistivity (TCR), in particular, the TCR is a few parts in 107/K for temperatures between 2 and 4.2 K. The fact that this alloy is commercially available and inexpensive, makes it very attractive as a low temperature resistance material for various applications. (author)

25

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 coating concept RSA-905 can be upgraded to a competitive alternative to steel in terms of price, performance and logistics. This paper presents some recent developments for improved mould performance of such concept. Hardness, wear resistance and adhesion are topics of interest and they can be applied by special coatings such as diamond-like carbon (DLC) and chromium nitride (CrN). These coatings make the aluminium alloy suitable for moulding mass production of small as well as larger optics, such as spectacle lenses.

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

2013-09-01

26

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

27

Roll casting of 5182 aluminium alloy  

OpenAIRE

Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed....

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

2009-01-01

28

Aluminium Alloy Cast Shell Development for Torpedoes  

Directory of Open Access Journals (Sweden)

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

Vijaya Singh

2005-01-01

29

Local electrochemical behaviour of 7xxx aluminium alloys:  

OpenAIRE

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

Andreatta, F.

2004-01-01

30

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

OpenAIRE

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

31

Aluminium alloys in municipal solid waste incineration bottom ash.  

Science.gov (United States)

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

Hu, Yanjun; Rem, Peter

2009-05-01

32

Structure and thermodynamic properties of aluminium-lanthanum alloys  

International Nuclear Information System (INIS)

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

33

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

International Nuclear Information System (INIS)

By using a torsion pendulum to measure the internal friction of iron-aluminium alloys containing between 25 and 50 atom per cent of aluminium, it has been possible to show the existence of three damping peaks due to interstitial carbon. Their evolution is followed as a function of the carbon content, of the thermal treatment and of the aluminium content. A model based on the preferential occupation of tetrahedral sites is proposed as an interpretation of the results. A study of the Zener peak in these substitution alloys shows also that a part of the short distance disorder existing at high temperatures can be preserved by quenching. (author)

34

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

35

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

36

Modern aluminium magnesium alloys and composites developed on their base  

International Nuclear Information System (INIS)

A review is presented on properties of high-strength aluminium and magnesium base alloys used, in particular, in nuclear industry during production of enriched uranium 235 (V96Ts). Alloy systems of Al-Cu-Li, Al-Cu-Mg, Mg-Nd-Y-Zr are considered. Processing, strength, corrosion properties of the alloys are reported. For heat resistant alloys the fields of application and the ranges of working temperatures are pointed out

37

Laser surface treatment of aluminium and magnesium alloys. Laserrandschichtbehandlung von Aluminium- und Magnesiumwerkstoffen  

Energy Technology Data Exchange (ETDEWEB)

To improve the wear resistance of a material in many tribological systems the hardening of a surface layer is necessary. This paper reviews results of laser surface treatment of Aluminium and Magnesium base alloys. The methods remelting, alloying, dispersing and cladding were conducted. Microstructure, hardness and brittleness of the produced layers were investigated. (orig.)

Weisheit, A. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik); Galun, R. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik); Haude, R. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik)

1994-06-01

38

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

OpenAIRE

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

39

Computer modelling of age hardening for cast aluminium alloys  

International Nuclear Information System (INIS)

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

40

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

41

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

42

Creep rupture data for aluminium alloys. Pt. 3  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-05-01

43

Aluminium alloys. Vol. 1. Their physical and mechanical properties  

Energy Technology Data Exchange (ETDEWEB)

The first volume of the proceedings contains papers which were held on the 11th International Conference on Aluminium Alloys (ICAA11) in Aachen vom 22-26 Sep, 2008. The main topics in this volume are: Alloy development; Casting and solidification; Recycling; Thermomechanical processing; Characterisation; Phase transformation; Recrystallization and Texture. (orig.)

Hirsch, Juergen [Hydro Aluminium Deutschland GmbH, Bonn (Germany). R und D Center Bonn; Skrotzki, Birgit [Bundesamt fuer Materialforschung und -pruefung, Berlin (Germany); Gottstein, Guenter (eds.) [RWTH Aachen (Germany). Inst. fuer Metallkunde und Metallphysik

2008-07-01

44

Dilute aluminium alloys: their potential in superconducting devices  

International Nuclear Information System (INIS)

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

45

Use of acoustic energy in sand casting of aluminium alloys  

OpenAIRE

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

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

2013-01-01

46

Remediation of phosphate-contaminated water by electrocoagulation with aluminium, aluminium alloy and mild steel anodes.  

Science.gov (United States)

The present study provides an electrocoagulation process for the remediation of phosphate-contaminated water using aluminium, aluminium alloy and mild steel as the anodes and stainless steel as the cathode. The various parameters like effect of anode materials, effect of pH, concentration of phosphate, current density, temperature and co-existing ions, and so forth, and the adsorption capacity was evaluated using both Freundlich and Langmuir isotherm models. The adsorption of phosphate preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The results showed that the maximum removal efficiency of 99% was achieved with aluminium alloy anode at a current density of 0.2 A dm(-2), at a pH of 7.0. The adsorption process follows second-order kinetics. PMID:18977084

Vasudevan, Subramanyan; Lakshmi, Jothinathan; Jayaraj, Jeganathan; Sozhan, Ganapathy

2009-05-30

47

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)

48

FACTORS INFLUENCING THE ENVIRONMENTAL BEHAVIOUR OF ALUMINIUM-LITHIUM ALLOYS  

OpenAIRE

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

Gray, A.

1987-01-01

49

Structure analysis of 3104 aluminium alloy applied to deep drawing  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

50

Aluminium alloys. Vol. 2. Their physical and mechanical properties  

Energy Technology Data Exchange (ETDEWEB)

The second volume of the proceedings contains papers which were held on the 11th International Conference on Aluminium Alloys (ICAA11) in Aachen vom 22-26 Sep, 2008. The main topics in this volume are: Simulation and modelling; Mechanical properties; Forming and Formability; Joining Technology; Corrosion and surface; Novel Materials (foams etc.); Applications. (orig.)

Hirsch, Juergen [Hydro Aluminium Deutschland GmbH, Bonn (Germany). R und D Center Bonn; Skrotzki, Birgit [Bundesamt fuer Materialforschung und -pruefung, Berlin (Germany); Gottstein, Guenter (eds.) [RWTH Aachen (Germany). Inst. fuer Metallkunde und Metallphysik

2008-07-01

51

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

52

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

OpenAIRE

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

53

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

International Nuclear Information System (INIS)

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

54

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

55

Positron studies of vacancy clustering in quenched aluminium and dilute aluminium alloys  

International Nuclear Information System (INIS)

Doppler broadening positron studies of annealing in quenched aluminium and dilute Al-Mg and Al-Zn alloys show that the effects of Mg and Zn on stage III annealing processes are essentially similar. Comparative analyses of the various measured annealing curves suggest that both microvoid and vacancy-loop formation are involved in stage III, the detailed balance being determined by the impurity concentration. (author)

56

Car body alloys and methods of corrosion protection: aluminium sheet  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-06-01

57

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.

58

External oxidation of aluminium-lithium alloys  

International Nuclear Information System (INIS)

The thermal oxidation dynamics of cold rolled aluminium-3%lithium foils was studied as a function of the annealing temperature, time and environmental gas pressure, by means of Rutherford backscattering spectrometry, thermal neutron depth profiling and scanning electron microscopy. Highly complex behaviour was found, which includes the depletion of lithium atoms from sub-surface layers and their enrichment in the surface area as oxide. The ratio of lithium to oxygen is usually far from stoichiometric. The surface transformation into oxide proceeds very rapidly in the first few minutes, and subsequently hardly shows any change. (orig.)

59

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

60

Grain boundary phenomena and failure of aluminium alloys  

OpenAIRE

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

Haas, Marc-jan

2001-01-01

61

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

62

Oxidation of solid aluminium-magnesium alloy doped by scandium  

International Nuclear Information System (INIS)

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

63

TEM microstructure investigations of aluminium alloys used as coating substrate  

OpenAIRE

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

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

2013-01-01

64

LASER CLADDING ON ALUMINIUM BASE ALLOYS  

OpenAIRE

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

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

1991-01-01

65

Advances in recycling of wrought aluminium alloys for added value maximisation  

OpenAIRE

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

Kevorkijan, Varuz?an

2012-01-01

66

Electron beam melt-hardening of aluminium alloys  

International Nuclear Information System (INIS)

In the first stage of the project, the binary alloys AlFe8, AlFe6, AlNi6, AlMn6, AlCr6, AlTi1,5 and AlZr1,5 were systematically melted and solidified. The technological testing has shown that especially the AlFe alloys, after localized melting and rapid solidification, have extremely good tensile strengths which at temperatures of between 200 and 3000C exceed all known heat resistant aluminium alloys. Two alternative methods have been investigated, namely superficial melting of a thin surface layer and a complete melt-hardening. As economic factors favour the use of the EB method for improvement of the surface properties, stages II and III of the project were concerned with the surface hardening of conventional aluminium materials (G-AlCu4Ti, G-AlSi8Cu3) by introducing an additional metal (Fe, Ni) along with the electron beam. The result is that one obtains a surface layer between 1 - 1.5 mm with an average hardness between 200 and 230 HV. Technological laboratory tests have shown that in this manner it is possible to obtain aluminium materials which possess a high wear resistance. (orig.)

67

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

68

Critical currents of deformed aging superconducting niobium-aluminium alloys  

International Nuclear Information System (INIS)

Using the transmission electron microscopy the dislocation structure in deformed and aged niobium-aluminium alloys (the Nb alloys with 7.13 and 14 at.% Al, as well as the Nb alloys with 9 and 10 at.% Al alloyed with 1 at.% Ce) has been studied. Using the electric conductivity method the aging kinetics has been studied. The critical currents of the alloys have been measured at 4.2 Deg K in magnetic fields. It is shown that the current-carrying capacity in a 60 koersted field exceeds 104 A/cm2. Considerations are presented regarding the superconductivity distortion mechanism by current in a magnetic field in these alloys. The dislocation structure with a high dislocation density in a heavily deformed supersaturated solid solution of aluminium in niobium of bcc lattice is more stable as regards the polygonization process, than the solid solution as regads decomposition at the same temperature. The color precipitations of the ?-Nb3Al dislocation phase probably form a developed multi-bound structure of thin (d< xi(T)) continuous current ways in deformed and aged alloys, which results in the occurrence of the superconductivity distortion mechanism by current in a magnetic field due to the critical velocity attained by the superconducting condensate. It is shown, that in a ferromagnetic Fermilfluid the contribution of nonlocal corrections to the interaction into the expression describing the spin wave frequency is equal, as to the value orderfrequency is equal, as to the value order, to the contribution of the local portion of the interaction. At this the effective constants of the exchange interaction involved in the spin wave dispersion law, in variance with the Heisenberg model, are equal only as regads their value order. The indicated discrepancy in the constants should be valid in the ferromagnetics of the iron group (Fe, Co, Ni)

69

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

International Nuclear Information System (INIS)

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

70

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.

71

Metallurgical aspects of corrosion resistance of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Aluminium is the second most often used metal after steel. In this paper, the most current uses of aluminium alloys are first summarised. Then, their different corrosion modes, i.e. pitting, crevice, filiform, galvanic and structural corrosion (including inter-granular, exfoliation and stress corrosion cracking) are reviewed, with particular attention paid to metallurgical factors controlling the corrosion process. For each mode, some instances of possible in-service failure are given, followed by the discussion of the involved mechanisms and the presentation of appropriate solutions to prevent corrosion. Last, passivity and polarisation behaviour are discussed with reference to stainless steels. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Reboul, M.C. [Pechiney Voreppe Research Centre France (France); CNRS-INP Grenoble, SIMAP-INP Grenoble, Universite France, Saint Martin d' Heres Cedex (France); Baroux, B. [SIMAP-INP, Grenoble University, 1130 rue de la piscine, Saint Martin d' Heres Cedex (France)

2011-03-15

72

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

73

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

International Nuclear Information System (INIS)

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

74

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route  

Energy Technology Data Exchange (ETDEWEB)

A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl{sub 3}. A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl{sub 3} is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl{sub 5} and UCl{sub 6}. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

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

2008-07-01

75

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route  

International Nuclear Information System (INIS)

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

76

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

77

Hot workability of aluminium alloys(II)  

International Nuclear Information System (INIS)

Continuous and interrupted torsion tests have been conducted in the temperature range of 320-520 deg C at constant strain rates of 1.26-5.71 x 10-3 sec-1 on an Al-Cu-Mg alloy. During the continuous deformation, dynamic recrystallization was observed above 370 deg C and the nucleation of the recrystallization at dislocation clusters or adjacent to second phase particle. The presence of deformation substructure in the recrystallized grain provided a direct evidence that recrystallization had occurred during the deformation. In the interrupted tests, duration of the interruptions were 10,20, or 40 sec at equal strain intervals of either 0.4 or 0.6. During the interrupted deformation, the major softening mechanism was static recovery and partially static recrystallization above 370 deg C. The degree of softening was augmented by increase in the temperature, the interruption strain, and the interruption time. (Author)

78

Secondary ageing in an aluminium alloy 7050  

International Nuclear Information System (INIS)

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

79

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

80

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

81

Friction stir welding of 6061 aluminium alloy  

International Nuclear Information System (INIS)

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

82

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

83

Modelling technological properties of commercial wrought aluminium alloys  

International Nuclear Information System (INIS)

The purpose of this paper is to model three important technological properties for aluminium alloys, based on their performance indices. The models are based on the chemical compositions and microstructure characteristics which are calculated using thermodynamical calculations. The properties that were modelled are the general corrosion, the weldability (MIG and TIG) and the machinability. The results from these models are to be used in materials selection and optimisation. The models clearly show that the general corrosion resistance is reduced for all alloy additions, except for small amounts of titanium. The largest influence on the corrosion is from copper and zinc. The weldability is negatively influenced by the copper and zinc-content, and for small additions of zirconium and titanium it is increased. The machinability is positively influenced by the hardness of the alloy or by adding lead or bismuth. For the non-heat-treatable alloys there was no influence from the composition to the corrosion resistance or the weldability. Copper and zinc which are added to increase the strength to the alloy strongly reduce both the weldability and the corrosion resistance but due to the increase in hardness increase the workability.

84

Frictional conditions between alloy AA6060 aluminium and tool steel  

International Nuclear Information System (INIS)

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

85

Frictional conditions between alloy AA6060 aluminium and tool steel  

Science.gov (United States)

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

Widerøe, Fredrik; Welo, Torgeir

2011-05-01

86

Failures of dies for die-casting of aluminium alloys  

Directory of Open Access Journals (Sweden)

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

Kosec, B.

2008-01-01

87

About resonance frequencies of aluminium alloy bending vibrations  

International Nuclear Information System (INIS)

Using ultrasonic method resonance frequencies of bending vibrations and elastic moduli of aluminium alloy SAV-1 samples are investigated. On the base of spectra of bending vibrations in low-frequency range data on values of a number of elastic properties are obtained as well as dispersion characteristics of main moduli for number of frequencies before and after ionizing irradiation (60Co, 5x103-1.6x107 Gy) of samples. Considerable stability of sample elastic moduli during common storage conditions and nonlinear dose dependence of these parameters within wide range of absorbed doses are pointed out. Possible causes of revealed effects of radiation modification of elastic properties of SAV-1 alloy are analyzed

88

Microstructural evolution of aluminium-magnesium alloys during thermomechanical processing  

Energy Technology Data Exchange (ETDEWEB)

During thermomechanical processing, local region within the stock undergo changes in strain path, which have systematic effects on deformed microstructure and subsequent recrystallisation behaviour. Only limited quantitative data are presently available. This paper presents results for the cumulative effects of repeated strain reversals on the dislocation structures, static recrystallisation kinetics and grain size of a series of high purity aluminium-magnesium alloys. The results show that dislocation density and local lattice curvature develop more slowly with strain reversals than with monotonic deformation, but essentially the same characteristics are observed. The slower development of the deformed structure is reflected by slower static recrystallisation kinetics and coarser recrystallised grain size. All the alloys show similar trends, which are discussed in terms of the role of geometrically necessary dislocations. (orig.)

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

2000-07-01

89

Image analysis used for aluminium alloy microstructure investigation  

Directory of Open Access Journals (Sweden)

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

M. Krupi?ski

2010-09-01

90

Contradictory effect of chromate inhibitor on corrosive wear of aluminium alloy  

International Nuclear Information System (INIS)

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

91

Creep rupture data for aluminium alloys. Pt. 1  

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-03-01

92

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

93

High effective organic corrosion inhibitors for 2024 aluminium alloy  

International Nuclear Information System (INIS)

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

94

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

95

Modelling hot deformation and textures of aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

96

Cold Spray Deposition of Titanium onto Aluminium Alloys  

Scientific Electronic Library Online (English)

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

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

2010-06-01

97

Two calculations concerning the critical aluminium content in Fe20Cr5Al alloys  

Energy Technology Data Exchange (ETDEWEB)

Alloys for high temperature applications rely on a protective oxide layer formed by selective oxidation. In Fe20Cr5Al type alloys the useful lifetime is governed by the depletion of aluminium by oxidation down to a critical aluminium content. Following spallation of the oxide scale the bare metal is exposed to air and catastrophic failure due to breakaway oxidation occurs if the aluminium content is too low. In this paper a model for the calculation of the critical aluminium content is presented. Based on Wagner's ideas on selective oxidation in ternary alloys, the critical aluminium content is calculated as that corresponding to the transition between external and internal oxidation. The resulting aluminium contents are temperature dependent and cover the range of values 0 to 3.5 wt.% reported in the literature. In the second part of the paper aluminium depletion profiles in Fe20Cr5Al plates have been calculated assuming a parabolic growth law for the oxidation process. The solution of the differential equation is an extension of the one dimensional solution presented by Whittle and coworkers for chromium depletion in FeCr sheet material, to three dimensions. Because of the increased consumption of aluminium at the corners of the sample, the critical aluminium content is first reached there. Based on the calculation, the reduction in lifetime, due to premature breakaway oxidation at the corners can be estimated. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

Strehl, G.; Borchardt, G. [Institut fuer Metallurgie, TU Clausthal, 38678 Clausthal-Zellerfeld (Germany); Beaven, P. [GKSS-Forschungszentrum Geesthacht, 21502 Geesthacht (Germany); Lesage, B. [LEMHE, CNRS UMR 8647, Universitee Paris XI, 91405 Orsay (France)

2005-11-01

98

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

99

Machinability of magnesium and aluminium alloys. Part II: formation of shavings  

International Nuclear Information System (INIS)

This work compares the methods of forming shavings during the machining of magnesium and aluminium alloys. The microstructural analysis of shavings explains the phenomena observed during machining. It has been confirmed that the shearing angle during machining of magnesium alloys is greater than that obtained with aluminium alloys. This also confirms the ductile/fragile behaviour of these two materials, the effects of which are seen in cutting resistance. Shavings obtained during drilling of magnesium alloys are shorter than those of 6061-T6, but are especially more regular than those of A356, and their size is independent of cutting speed. All of these results explain the major difference in behaviour of these two types of material: magnesium alloys are clearly easier to machine than aluminium alloys

100

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

OpenAIRE

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 ...

Froustey, C.; Naimark, O.; Bannikov, M.; Oborin, V.

2010-01-01

101

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

International Nuclear Information System (INIS)

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

102

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

International Nuclear Information System (INIS)

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

103

A review of friction stir welding of AA 6061 aluminium alloy  

OpenAIRE

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

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

2011-01-01

104

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

OpenAIRE

AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties...

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

2008-01-01

105

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

OpenAIRE

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

106

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

107

Titrimetric determination of aluminium in zinc-aluminium alloys, with edta and a cu(II)-selective electrode.  

Science.gov (United States)

The end-point for the titration of EDTA with Cu(II), as measured by a Cu(II)-selective electrode, varies with pH and temperature. Moreover, the effect of pH and temperature on the behaviour of this electrode differs according to whether fluoride is present. As a consequence, the determination of aluminium in zinc-aluminium alloys by the Freegarde and Allen method with use of a Cu(II)-selective electrode must be performed with close control of pH and temperature to maximize accuracy and repeatability. PMID:18963452

Steger, H F

1983-09-01

108

Microscopic observation of pattern attack by aggressive ions on finished surface of aluminium alloy sacrificial anode  

International Nuclear Information System (INIS)

This paper presents the results of a microscopic observation on submerged finished surface of aluminium alloy sacrificial anode. Experimental tests were carried out on polished surface aluminium anode exposed to seawater containing aggressive ions in order to observe of pattern corrosion attack on corroding surface of anode. Results have shown, at least under the present testing condition, that surface of sacrificial anode were attack by an aggressive ion such as chloride along grain boundaries. In addition, results of microanalysis showed that the corrosion products on surface of aluminium alloy have Al, Zn and O element for all sample and within the pit was consists of Al, Zn, O and Cl element. (author)

109

A study of the chemical state of tin layers deposited on various aluminium alloys and electroplated with copper  

International Nuclear Information System (INIS)

The interaction between several aluminium alloys and tin deposited onto then has been studied by means of Moessbauer spectroscopy. The silicon content in the aluminium helps most the intensive alloying at the interfaces. Copper electroplated onto the deposited tin layer also forms an alloy with the latter. (author)

110

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

International Nuclear Information System (INIS)

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

111

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

International Nuclear Information System (INIS)

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

112

Relationship between hardness and abrasive wear for some aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-07-01

113

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)

114

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

International Nuclear Information System (INIS)

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

115

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)

116

The neodymium recovery from liquid alloys with aluminium and molten salt mixtures  

International Nuclear Information System (INIS)

Studied is the neodymium distribution between its alloys with aluminium and salt molten mixtures depending on salt phase composition in the process of neodymium recovery from liquid alloys. It is shown that the equilibrium of the Al+Nd3 reversible Al3++Nd reaction depends to a great extent on anion content of a salt phase. It is reasonalbe to use chloride melts to recover neodymium from the alloy with aluminium. Neodymium may be completely recovered in the form of metallic phase form chloride-fluoride melts

117

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

Directory of Open Access Journals (Sweden)

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

A. Dolata-Grosz

2008-08-01

118

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.

119

Galvanic corrosion of laser weldments of AA6061 aluminium alloy  

International Nuclear Information System (INIS)

Galvanic corrosion of laser welded AA6061 aluminium alloy, arising from the varying rest potentials of the various weldment regions, was examined. The weld fusion zone is found to be the most cathodic region of the weldment while the base material is the most anodic region. The rate of galvanic corrosion, controlled by the cathodic process at the weld fusion zone, increases with time until a steady state maximum is reached. On galvanic corrosion the corrosion potential of the weld fusion zone shifts in the positive direction and the free corrosion current increases. It is proposed that the cathodic process at the weld fusion zone causes a local increase in pH that in turn causes dissolution of the surface film resulting in the loss of Al to solution and the increase of intermetallic phases. The increase in galvanic corrosion may result from either the build up of the intermetallic phases in the surface layer and/or significant increase in surface area of the weld fusion zone due to the porous nature of the surface layer

120

Galvanic corrosion of laser weldments of AA6061 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

Galvanic corrosion of laser welded AA6061 aluminium alloy, arising from the varying rest potentials of the various weldment regions, was examined. The weld fusion zone is found to be the most cathodic region of the weldment while the base material is the most anodic region. The rate of galvanic corrosion, controlled by the cathodic process at the weld fusion zone, increases with time until a steady state maximum is reached. On galvanic corrosion the corrosion potential of the weld fusion zone shifts in the positive direction and the free corrosion current increases. It is proposed that the cathodic process at the weld fusion zone causes a local increase in pH that in turn causes dissolution of the surface film resulting in the loss of Al to solution and the increase of intermetallic phases. The increase in galvanic corrosion may result from either the build up of the intermetallic phases in the surface layer and/or significant increase in surface area of the weld fusion zone due to the porous nature of the surface layer.

Rahman, A.B.M. Mujibur; Kumar, S. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Gerson, A.R. [Applied Centre for Structural and Synchrotron Studies, University of South Australia, Mawson Lakes, SA 5095 (Australia)], E-mail: Andrea.Gerson@unisa.edu.au

2007-12-15

121

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

International Nuclear Information System (INIS)

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

122

Mushy Zone Properties and Castability of Aluminium Foundry Alloys  

Energy Technology Data Exchange (ETDEWEB)

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

Dahle, A.K.

1996-01-01

123

Determination of the Uranium Content of Aluminium Alloys  

International Nuclear Information System (INIS)

Many materials testing reactors use as fuel an alloy of aluminium and enriched uranium. The amount of U235 in each fuel element must be known accurately. The techniques used to determine this are not only simple in principle but also varied; they include measurement of the alloy density, counting of the ?-activity of the U235, chemical analysis, determination of the isotopic content and evaluation of radiograph blackening. Unfortunately, all these methods possess more or less serious disadvantages when used for inspection on an industrial scale. The measurement of alloy density by Archimedes’ method gives sufficiently accurate results if care is taken and the densities of the constituent metals are exactly known. The procedures employed, however, make this a very slow method. Moreover, the isotopic content must be known with great accuracy if the amount of U235 contained is to be determined. Counting the y-activity of the U235 yields a direct evaluation of this isotope, but the many parameters of a single-channel spectrometer require the use of accurately known standards and exceptionally stable counting facilities. Nevertheless, this method is in the authors’ opinion the most suitable one for determinations on an industrial scale; and although the choice of standards requires care, and it is a slow and expensive matter to establish them, for any given level of production the choice is made once and for all, the only pris made once and for all, the only practical difficulty being to ensure the continued electronic stability of the installation. The other methods mentioned - chemical and isotopic analyses, and densitometry - are not. in common use. Measurement of the blackening of a radiograph is not sufficiently precise and does not permit the determination of uranium content with the required degree of accuracy. Densitometric examination of radiographs is nevertheless very useful, even indispensable, in assessing the homogeneity of an alloy or its mean content compared with two extreme standards on the same negative. Chemical and isotopic analyses can be very accurate, but they are also destructive: certain working precautions must be taken in order on the one hand to eliminate errors due to chemical impurities in the alloy, and on the other to allow for the presence of the different uranium isotopes, the proportions of which must be known for an exact calculation of the U235 content. Finally, the authors show that the measurement of uranium content must be carried out in several stages, each involving all the resources of relatively simple techniques. The value and limits of each technique are discussed. The choice of standards is based on the evidence of radiographs. The exact U235 content of the standards is determined by chemical and isotopic analyses. Production-line inspection is carried out by measuring the alloy density or by counting the ?-activity of the U235. The precision of the two methods is comparable (± 0.5% relative to the uranium content). From the economic point of view the authors recommend determining the U235 content by y-counting whenever a large number of components of a given shape have to be inspected. This subject has already been dealt with. The paper reports and discusses the results of an industrial experiment. (author)

124

Modelling research of hydrogen desorption from liquid aluminium and its alloys  

OpenAIRE

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

Saternus, M.

2011-01-01

125

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

OpenAIRE

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

126

HIGH PURITY ALUMINIUM-LITHIUM MASTER ALLOY BY MOLTEN SALT ELECTROLYSIS  

OpenAIRE

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

127

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.

128

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

Science.gov (United States)

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.

Mori, K.; Abe, Y.; Kato, T.; Sakai, S.

2010-06-01

129

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

Directory of Open Access Journals (Sweden)

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

Oladele Isiaka Oluwole

2010-06-01

130

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

Scientific Electronic Library Online (English)

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

Oladele Isiaka, Oluwole; Omotoyinbo Joseph, Ajibade.

2010-06-01

131

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)

132

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

133

Combined thermal treatment and stirring of liquid aluminium alloy preventing formation of primary intermetallic compounds in ingots  

International Nuclear Information System (INIS)

A study was made on combined effect of thermal treatment and stirring of liquid complex aluminium alloy on structure of ingots, produced by the method of continuous casting. it is shown that the reason of formation of primary intermetallic compounds in ingots of 1421 aluminium alloy lies in the presence of chemical heterogeneities Alx(Zr,Sc) in prepared liquid 1421 alloy. Thermal treatment and intensive mixing of liquid aluminium 1421 alloy during its preparation enable to remove intermetallic compounds from ingots. 6 refs., 2 figs

134

Treatment of titanium alloy by pulsed heterogeneous plasma with surface burning off and alloying by aluminium and nickel  

International Nuclear Information System (INIS)

Methods of metallography, scanning electron microscopy and X-ray analysis were used to study the effect of technological parameters on thickness, alloying degree, phase composition, structure and properties of titanium alloy surface modified by aluminium and nickel impulse alloying with surface partial melting by heterogeneity plasma of capacitor discharge. Regimes of plasmacondensate coatings formation and surface modification are determined. Fine-grained alloyed layers of a few tens microns depth have homogeneous by depth multiphase composition dependent on treatment regime. Intermetallic hardening leads to increase of hardness and wear resistance of surface layers

135

Analysis of intermetallic particles in AlSi1MgMn aluminium alloy  

Directory of Open Access Journals (Sweden)

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

G. Mrówka-Nowotnik

2007-01-01

136

Evolution of the microstructure of ageing aluminium alloys in high-energy ion implantation  

International Nuclear Information System (INIS)

It is well-known that the radiation defects, formed during ion implantation, have a strong effect on the structural-phase condition of the metals and alloys and change of the properties. In previous work, we carried out investigations of the changes of the structure and properties of thermally non-hardened alloys of the system Al-Mn (AMts) implanted with high-energy Ne ions. In this work, these investigations were continued for thermally hardened alloys, i.e. ageing aluminium alloys

137

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)

138

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)

139

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

Energy Technology Data Exchange (ETDEWEB)

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 Wenbin [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, 100875 (China); Wang Chao [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, 100875 (China); Deng Zhiwei [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, 100875 (China); Chen Ruyi [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, 100875 (China); Li Yongliang [Analytical and Testing Centre, Beijing Normal University, Beijing, 100875 (China); Zhang Tonghe [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, 100875 (China)

2002-11-11

140

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

International Nuclear Information System (INIS)

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 ?-Al2O3 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

141

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

DEFF Research Database (Denmark)

AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains factors: • a weak redox activity of the polymer which passivate the metal, • a proton involving self-healing process taking place at the polymer–metal interface, which contributes to delay local acidiWcation in Wrst steps of corrosion on EB coated aluminium surfaces.

Cecchetto, L; Ambat, Rajan

2007-01-01

142

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

OpenAIRE

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

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

2012-01-01

143

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

OpenAIRE

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

144

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

OpenAIRE

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

145

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

OpenAIRE

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

146

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

147

Small fatigue crack growth in aluminium alloy EN-AW 6082/T6.  

Czech Academy of Sciences Publication Activity Database

Ro?. 32, ?. 12 (2010), s. 1913-1920. ISSN 0142-1123 R&D Projects: GA ?R GA101/07/1500 Institutional research plan: CEZ:AV0Z20410507 Keywords : Aluminium alloys * small cracks * grack growth rate Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.799, year: 2010

Jíša, D.; Liškutín, P.; Kruml, Tomáš; Polák, Jaroslav

2010-01-01

148

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

149

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

Scientific Electronic Library Online (English)

Full Text Available In this work, solution heat treatments at different temperatures were performed in a commercial based AA7050 aluminium alloy, with and without titanium addition, produced by mechanical alloying and hot extrusion with the aim to investigate the effect of titanium addition and mechanical alloying in t [...] he precipitates stability. The same heat treatment conditions were used in a reference sample obtained from a commercial AA7050 alloy. Solution heat treated samples were characterised by differential scanning calorimetry (DSC), optical microscopy and hardness test. Once the better temperature for the solution treatment of modified alloys was defined, the ageing curve at 120 °C was obtained to verify the effect of milling and Ti addition in the precipitation and in the maximum values of hardness obtained for the alloys.

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

2007-06-01

150

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.

151

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.

152

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

153

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-07-01

154

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

DEFF Research Database (Denmark)

Effect of alloy composition and prior surface finish on the optical appearance of the anodised layer on aluminium alloys was investigated. Four commercial alloys namely AA1050, Peraluman 706, AA5754, and AA6082 were used for the investigation. Microstructure and surface morphology of the substrate prior to anodising were analysed using scanning electron microscopy and atomic force microscopy. The optical appearance of the anodised surface with and without sealing was investigated using a photography setup, photospectrometry and bidirectional reflectance distribution function. It was found that the roughness of the as-etched surface increases with the degree of alloying due to second phase particles making the reflection more diffused, and that the as-etched surface morphology is similar to the oxide–substrate interface after anodising. Proper polishing is achieved on hard alloys and the glossy appearance was kept for alloys of high purity. Sealing made the specular reflection of the mechanically polished specimens more distinct.

Aggerbeck, Martin; Canulescu, Stela

2014-01-01

155

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

International Nuclear Information System (INIS)

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

156

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

Energy Technology Data Exchange (ETDEWEB)

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 < Al-In < Al-Sn {approx} Al-Sn-In. The anodic dissolution of the Al-Sn and Al-Sn-In alloys started at open circuit potential which is only 0.45 V more positive than the thermodynamic Al{sup 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.

Gudic, S., E-mail: senka@ktf-split.hr [Department of Electrochemistry and Materials Protection, Faculty of Chemistry and Technology, Teslina 10/V, 21000 Split (Croatia); Smoljko, I.; Kliskic, M. [Department of Electrochemistry and Materials Protection, Faculty of Chemistry and Technology, Teslina 10/V, 21000 Split (Croatia)

2010-06-01

157

Interaction of carbon filaments with aluminium alloys, containing zirconium  

International Nuclear Information System (INIS)

The effect of carbide-forming metal-zirconium doping in the aluminium base melt on wettability by melts of reinforced filaments is considered. Regularities of melt spreading over the surface of carbographite filaments are disclosed. Kinetics of ZrC composition transition layer formation is studied. Diffusion constants and activation energy of transition zone formation processes are determined according to the experimental data

158

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

159

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

160

An approach for continuous cooling transformation (CCT) diagrams of aluminium alloys  

International Nuclear Information System (INIS)

Two different kinds of time temperature transformation (TTT) diagrams are known. The first one are isothermal transformation (IT) diagrams and the second one continuous cooling transformation (CCT) diagrams. These diagrams are important for the correct heat treatment of aluminium alloys, because they provide information about the required quenching rate, which is necessary to obtain a supersaturated solid solution during age hardening. Furthermore, it is possible to determine the lowest quenching rate, which permits both a high strength and a small distortion of the component after age hardening. In the literature IT diagrams for different aluminium alloys are available. To determine these diagrams, a solution annealing followed by quenching to defined temperatures is necessary. At these temperatures the alloy is kept isothermally until a transformation has started. These diagrams are not directly portable on continuous cooling, because of the different cooling paths. (orig.)

161

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

Directory of Open Access Journals (Sweden)

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

Maros Martinkovic

2012-05-01

162

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)

163

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

Directory of Open Access Journals (Sweden)

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

Nikolay A. Suy

2013-03-01

164

Investigation into the strength of components made of UFG aluminium alloys  

OpenAIRE

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

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

2008-01-01

165

Study of mechanical properties in neutron irradiated aluminium base alloys  

International Nuclear Information System (INIS)

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

166

Electron irradiation of copper-aluminium alloys: II. Growth and density of the observed damage  

International Nuclear Information System (INIS)

Specimens of copper-aluminium alloys (with aluminium content varying between 0 and 16at%) have been irradiated in a high voltage electron microscope over the temperature range 300-550K using a double-tilting, heating specimen stage. The specimens were prepared by standard disc electropolishing techniques and care was taken to ensure that known post-preparation annealing procedures were adopted. Measurements made included overall defect (interstitial loop) densities and depth distributions, densities of loops on different planes, defect size distributions and growth rates, and 'denuded zone' widths. The effects of changing specimen foil thickness were investigated in detail

167

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

OpenAIRE

The main problems caused by improper gating are entrained aluminium oxide films, cuts and washes, low casting yield and entrapped gas. This study describes the design of a gating system to produce thin Aluminium cast alloy plates of different sizes and thicknesses of 4mm, 6mm, 8mm, and 10mm using the non-pressurized gating with ratio of 1:4:4 and green sand moulding technique. The gating design was based on the laws of fluid mechanics and empirical rules of gating for non ferrous metals. The ...

Anjo, Victor; Khan, Reyaz

2013-01-01

168

Surface modification of aluminium alloys using hybrid treatment techniques  

International Nuclear Information System (INIS)

The application of electron and laser beams to the modification of metal and alloys opens up new possibilities of improving the materials properties. In recent years, the studies aimed at developing new materials have brought about the development of hybrid treatment techniques. These techniques perform an additional alloying in the zone treated, which has a substantial effect on the physical and mechanical properties of the materials processed. In this work we report results on the microstructural changes and mechanical properties of heat-treated AlSi12CuNiMg alloys resulting from additional alloying with Fe, Co, Ni, Cr by hybrid electron-beam techniques. It is established that the mechanical properties of Al-Si alloys can be improved by means of additional alloying with Fe, Co, Ni, Cr by hybrid electron-beam techniques. The specimens' properties practically do not change after heat-treatment (aging) for up to 200 hours at 250 C.

169

Superlattices in iron-rich iron-aluminium alloys  

International Nuclear Information System (INIS)

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

170

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

OpenAIRE

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

171

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

OpenAIRE

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

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

2014-01-01

172

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

OpenAIRE

The studied material is a 5xxx aluminium alloys containing 2 types of intermetallic particles : Alx(Fe;Mn) and Mg2Si. It is usually used in car industry as reinforcement pieces or in packaging industry, such as bottle liquid box lid. Scanning electronic microscope coupled with EDX analysis shows complex shapes of intermetallic particles. The particle shape is obtained during the solidification of alloys. Particles fill vacant spaces between aluminium grains. Therefore final sheet properties d...

Estelle Parra-Denis; Nicolas Moulin; Dominique Jeulin

2011-01-01

173

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

OpenAIRE

Aluminium alloy reinforced with Nano-sized ZrO2 particles are widely used for high performance applications such as automotive, military, aerospace, and electricity industries because of their improved physical and mechanical properties. In this research, Zirconium Oxide (ZrO2) Nano particles were synthesized by Solution Combustion Synthesis process. The Nano particles were characterized by Powder X-ray diffraction (PXRD) and TEM. A356.1 Aluminium alloy was reinforced with 0.5...

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

2014-01-01

174

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

175

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

176

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

Directory of Open Access Journals (Sweden)

Full Text Available Electrical discharge machining (EDM has been recognized as an efficient production method for precision machining of electrically conducting hardened materials. Copper and aluminium are used as electrode materials in this process with Kerosene oil as the dielectric medium. In this work, the behavior of copper and aluminium electrodes on electric discharge machining of EN-8 alloy steel had been studied. Keeping all other machining parameters same, the hardened work material was machined with the two electrodes at different values of peak current, pulse-on time & duty factor according to 23 full factorial design. It has been found that copper shows better results than aluminium in term of surface finish (?m in same dielectric media. Therefore, copper is recommended as a good electrode material.

DHANANJAY PRADHAN

2011-07-01

177

Corrosion of alloys of the niobium--titanium--aluminium system  

International Nuclear Information System (INIS)

The mechanical properties and corrosion resistance of niobium--titanium--aluminum alloys in 20 percent HCl and 40--75 percent H2SO4 at 40 and 1000C are considered. Current density vs potential and corrosion rate vs potential potentiostatic curves plotted in 75 percent H2SO4 at 1400C for the alloys with different titanium contents at a constant content of aluminum and also for alloys with a constant titanium content at different contents of aluminum are given. It was shown that the corrosion resistance of the alloys in 75 percent H2SO4 at 1400C is an exponential function of the atomic content of the alloying components (Ti, Al) in them; aluminum vitiates the corrosion resistance very strongly

178

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

DEFF Research Database (Denmark)

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

Din, Rameez Ud; Jellesen, Morten Stendahl

179

The effect of alloying elements and the surface oxide layer on the corrosion damage of aluminium alloys in acidic atmosphere  

International Nuclear Information System (INIS)

Ten years of atmospheric exposure tests in four different climates were carried out on three different aluminium alloys without surface treatment and with various kinds of anodizing in order to determine the corrosion resistance. The type and degree of corrosion was evaluated in cross section metallographically and by SEM imaging. The corrosion products were investigated by EDAX microanalysis. AC admittance measurements seemed excellent in rapid testing of the corrosion damage of anodized samples

180

Erosion of molybdenum alloy with aluminium nitride additions  

International Nuclear Information System (INIS)

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

181

Laser surface treatment of magnesium alloys with aluminium oxide powder  

Directory of Open Access Journals (Sweden)

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

L.A. Dobrza?ski

2009-11-01

182

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

183

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-04-15

184

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

Scientific Electronic Library Online (English)

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

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

2011-11-01

185

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

186

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

International Nuclear Information System (INIS)

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

187

Thickness effects on the mechanical properties of micro-arc discharge oxide coatings on aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

Weight-saving materials are becoming increasingly important, especially in the automotive and aerospace industries. Design engineers would thus like to make more extensive use of light metals such as aluminium, titanium, magnesium and their alloys; however, these materials tend to have poor wear resistance. Previous treatments and coatings applied to aluminium alloys, for example by traditional processes such as hard anodising and thermal spraying, have suffered from the low load support from the underlying material and/or insufficient adhesion, which reduces their durability. Also, although TiN-, CrN- or DLC-coated aluminium alloys (using various PVD methods) can achieve a high surface hardness, in practice they often exhibit poor performance under mechanical loading, since the coatings are usually too thin to protect the substrate from the contact conditions. In the work reported here, a plasma electrolysis technique known as micro-arc discharge oxidation (MDO) was investigated; thick and hard oxide ceramic layers were fabricated on BS Al-6082 aluminium alloy by this method. The phase composition and microstructure of the MDO coatings were investigated by XRD, SEM and EDX analyses. A number of adhesion and tribological sliding and impact wear tests were also performed. It was found that Al-Si-O coatings with a hardness of up to 2400 HV and with excellent wear resistance and load support could be formed. The thickness of the coatings significantly influenced the mechanical properties. In terms of tribological performance, the thicker coatings performed best in sliding, scratch and impact tests whilst thin coatings were also surprisingly effective in both impact and low-load sliding. Coatings of intermediate thickness provided relatively poor performance in all tribological tests. (orig.)

Nie, X.; Leyland, A. [Hull Univ. (United Kingdom). Research Centre in Surface Engineering; Song, H.W. [Institute of Low Energy Nuclear Physics, Beijing (China); Yerokhin, A.L. [Laboratory of Electrophysical and Electrochemical Treatment, Tula State University, Tula (Russian Federation); Dowey, S.J. [Ion Coat Ltd, Newlands House, Newlands Science Park, Hull (United Kingdom); Matthews, A. [Research Centre in Surface Engineering, University of Hull, Hull (United Kingdom)

1999-09-01

188

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

OpenAIRE

In this research solidification characteristic of metal matrix composites consisted of titanium carbide particulate reinforced aluminium-11.8% silicon alloy matrix is performed. Vortex mixing and permanent casting method are used as the manufacturing method to produce the specimens. Temperature measurements during the casting process are captured and solidification graphs are plotted to represent the solidification characteristic. The results show, as volume fraction of particulate reinforcem...

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

2012-01-01

189

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

International Nuclear Information System (INIS)

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

190

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

International Nuclear Information System (INIS)

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

191

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

Science.gov (United States)

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

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

2008-02-01

192

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

OpenAIRE

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

Tanner, D. A.

1999-01-01

193

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

OpenAIRE

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

194

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

OpenAIRE

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

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

2002-01-01

195

Hot-crack test for aluminium alloys welds using TIG process  

OpenAIRE

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

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

2010-01-01

196

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

197

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

Directory of Open Access Journals (Sweden)

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

E. Lepka

2007-07-01

198

Laser surface treatments for adhesion improvement of aluminium alloys structural joints  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-08-15

199

DYNAMIC RESPONSE AND MICROSTRUCTURAL ASPECTS OF CP271 AND CP274 ALUMINIUM-LITHIUM ALLOYS  

OpenAIRE

The mechanical behaviour and microstructures of CP271 and CP274 Aluminium-Lithium alloys under dynamic loading by tension and compression were investigated. The strain rate effect on the mechanical behaviour has been studied by means of tension test in the strain rate range 10-5 S-1 to 103 S-1 at room temperature. Dynamic tests were performed with a split- Hopkinson bar. The fracture surface and failure processes are analyzed by scanning electron microscopy. Compression test were performed in...

Chiem, C.; Lee, W.; Meyer, P.

1988-01-01

200

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

OpenAIRE

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...

Barbaux, Y.; Pons, G.

1993-01-01

201

Amplitude-dependent internal friction of high-strong aluminium alloys measured by ultrasonic method  

International Nuclear Information System (INIS)

The automatic installation is created for measurement of internal friction using a resonance principle of excitation and detection of sample oscillations, not in the auto generating mode, but in a mode of frequency scanning of excitation coil current. The installation enables one to estimate consequences of action of various factors, such as an exposure, annealing, mechanical loading, effects of liquid metals and various chemical mediums on samples. Amplitude-frequency characteristics of aluminium alloy internal friction are measured by the created installation. (author)

202

High-modulus aluminium alloys containing beryllium and magnesium  

International Nuclear Information System (INIS)

The data on studying the structure and properties of the Al-(10-70) % Be-(0-10) % Mg alloys are summarized. It is established that the Al-Be-Mg alloys in the cast state are characterized by the relatively low strength and plasticity values. With the increase in the deformation rate there occurs simultaneously the increase in the strength and plasticity due to the particles grinding and change in the form of the beryllium constituent and decrease in the distance between them. It is noted that the Al-Be alloys do not strengthen by the thermal treatment and are well deformed at 300-400 Deg C. The alloys are characterized by the high elasticity modulus and are not subjected neither to the intercrystallite corrosion no to the corrosion under pressure

203

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.)

204

Surface microhardening in a lithium implanted aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

This paper describes changes observed in microhardness after implanting energetic lithium ions into pure aluminum and its 2024-T351 alloy. The addition of lithium to aluminum lowers the density and increases both the modulus of elasticity and tensile strength. Thus, these properties make such alloys attractive in aerospace applications. The authors believe that this is the first report where lithium implantation has been used to evaluate near surface changes.

Singh, A.; Fiset, M.; Knystautas, E.J.; Lapointe, R.

1984-09-01

205

A predictive fatigue life model for anodized 7050 aluminium alloy  

OpenAIRE

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

206

Stereometry specification of anodisation surface of casting aluminium alloys  

OpenAIRE

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

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

2008-01-01

207

Advances in aluminium alloy products for structural applications in transportation  

International Nuclear Information System (INIS)

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

208

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

209

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

International Nuclear Information System (INIS)

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

210

Study of deformation condition influence on texture of hardenable aluminium alloys  

International Nuclear Information System (INIS)

The texture in AlMgSi and AlMgSiCu alloys was studied after annealings and cold rolling with reduction of 20, 40, 60 and 85%. Texture analysis was conducted with the help of X-ray diffractometer. Cold rolling conditions were found to have a great affect on texture evolution in aluminium base alloys. Texture components (3) and (331) appeared to be very feeble. Intensity of (200) component increased strongly with deformation degree compared to (220) and (311) texture constituents. The texture evolution is considered in connection with slip deformation mechanism

211

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

International Nuclear Information System (INIS)

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

212

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-05

213

Analysis of low cycle fatigue in AlMgSi aluminium alloys  

OpenAIRE

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

214

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

International Nuclear Information System (INIS)

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

215

Development of elevated temperature AlFe(X) PM aluminium alloys by rapid solidification processing  

International Nuclear Information System (INIS)

Rapid solidification (RS) process enables to increase the amount of iron as an alloying element compared to conventional aluminium alloys. The microstructural features, the grain size, the dendrite arm spacing, and constituent particles are refined. The fine and stable microstructure originating from the RS causes enhanced strength properties, better heat, wear and corrosion resistance. Alloys prepared on the base of 4N Al containing 6-8 % of Fe with addition of Ni, Co, or Si were studied. Rapidly solidified powder had been produced by inert gas atomization. The powder had been compacted by cold isostatic pressing followed by vacuum degasing and hot extrusion. It was found that fairly good properties can be achieved with Al6Fe2Co alloy: with an elongation of 8-10 % the UTS was 460 MPa at room temperature and 240 MPa at a temperature of 300degC. The stability and change of the microstructure at elevated temperature is discussed in detail

216

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

217

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.

218

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)

219

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

220

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)

221

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.

222

Electrochemical oxidation of aluminium-cerium alloys in acid solutions  

Energy Technology Data Exchange (ETDEWEB)

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

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

1986-02-10

223

Premature Cracking of Dies for Aluminium Alloy Die-Casting  

Directory of Open Access Journals (Sweden)

Full Text Available Dwie identyczne matryce do ci?nieniowego odlewania stopów aluminium zosta?y przedwcze?nie wycofane z eksploatacji z powodu wyst?pienia na ich powierzchniach roboczych szeregu równoleg?ych p?kni??. Kierunek propagacji p?kni?? pokry w a? si? z kierunkiem pasmowo?ci mikrostrukturalnej a samo tworzenie si? p?kni?? by?o skutkiem niew?a?ciwej obróbki cieplnej matryc. Stwierdzono nieprawid?ow? orientacj? geometryczn? matrycy wrzgl?dem kierunku w?ókien struktury pierwotnej. Badania przy u?yciu skaningowego mikroskopu elektronowego z wykorzystaniem techniki EDS wykaza?y, ?e przyczyn? powstawania p?kni?? matryc by?a nieprawid?ow? przeprowadzona obróbki cieplna matryc.

Paw?owski B.

2013-12-01

224

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

Science.gov (United States)

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

Wu, Y. C.; Li, P. H.; Xue, X. D.; Wang, S. J.; Kallis, A.; Coleman, P. G.; Zhai, T.

2011-01-01

225

High speed twin roll casting of 6016 aluminium alloy strip  

OpenAIRE

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

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

2007-01-01

226

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

Science.gov (United States)

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

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

227

Experimental research on the ultimate strength of hard aluminium alloy 2017 subjected to short-time radioactive heating  

International Nuclear Information System (INIS)

Highlights: ? Ultimate strength at transient heating is critical to security design of missiles. ? We measure the ultimate strength of alloy 2017 subjected to transient heating. ? Experimental results at transient heating are lacking in strength design handbook. ? Ultimate strength of alloy 2017 experimented is much higher than handbook value. ? The results provide a new method for optimal design of high-speed flight vehicles. -- Abstract: Alloy 2017 (Al–Cu–Mg) is a hard aluminium alloy strengthened by heat treatment. Because of its higher strength, finer weldability and ductility, hard aluminium alloy 2017 has been widely used in the field of aeronautics and astronautics. However, the ultimate strength and other characteristic mechanical parameters of aluminium alloy 2017 in a transient heating environment are still unclear, as these key mechanical parameters are lacking in the existing strength design handbook. The experimental characterisation of these critical parameters of aluminium alloy 2017 is undoubtedly meaningful for reliably estimating life span of and improving safety in designing high-speed flight vehicles. In this paper, the high-temperature ultimate strength, loading time and other mechanical properties of hard aluminium alloy 2017 under different transient heating temperatures and loading conditions are investigated by combining a transient aerodynamic heating simulation system and a material testing machine. The experimental results reveal that the ultimate strength and loading capability of aluminium alloy 2017 subjected to transient thermal heating are much higher than those tested in a long-time stable high-temperature environment. The research of this work not only provides a substantial basis for the loading capability improvement and optimal design of aerospace materials and structures subject to transient heating but also presents a new research direction with a practical application value.

228

Microstructures and mechanical properties of an Osprey aluminium 7000 alloy  

OpenAIRE

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

229

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

International Nuclear Information System (INIS)

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

230

Continuous cooling transformation diagrams for 6XXX aluminium alloys  

International Nuclear Information System (INIS)

Continuous cooling transformation diagrams of aluminum solid solution decomposition in range of cooling rates 100-1900 deg. C/h were built for some alloys of Al-Mg-Si-Fe system. Influence of cooling rate and chemical composition on temperatures of start and finish of solution decomposition was determined.

231

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-09-01

232

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

233

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

International Nuclear Information System (INIS)

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

234

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.

235

Corrosion inhibition of 7000 series aluminium alloys with cerium diphenyl phosphate  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-02-03

236

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

237

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

238

Use of Waste Flyash in Fabrication of Aluminium Alloy Matrix Composite  

Directory of Open Access Journals (Sweden)

Full Text Available Waste flyash from two different industries (named as type A and type B were utilized as reinforcement in fabricating aluminium alloy based matrix composites (AMC. The AMCs were fabricated by continuous stir-casting method in a bottom pouring furnace at 7000C. Casting was made in rectangular metal mould having dimension 250x20x45 mm3. Effect of adding different flyash contents were realized thorough various mechanical behaviour tests. For measuring mechanical properties such as Brinell hardness, impact strength, compression strength, tensile strength, and micro hardness of both the AMCs, samples were prepared as per the standards in the mechanical workshop. The flyash distributions in the AMCs were confirmed through microstructure examination conducted on image analyzer and scanning electron micrographs. Results revealed that there is a great effect of reinforcing different flyash in aluminium alloy matrix composites. Type B flyash gave more enhanced mechanical properties compared to type A flyash. Thus, selection of flyash for reinforcement was found one of the most important criteria for fabricating aluminium matrix composites.

Ajit Kumar Senapati

2014-05-01

239

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

Directory of Open Access Journals (Sweden)

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

Victor ANJO

2013-11-01

240

Texture-induced anisotropy in asymmetrically rolled aluminium alloys  

Energy Technology Data Exchange (ETDEWEB)

The formability of Al alloys is strongly correlated to the crystallographic texture and thus can be controlled by thermomechanical processing parameters. Texture-induced anisotropy is studied in asymmetrically hot and cold rolled Al alloys from the 6xxx series. It is found that the strain mode of both hot and cold rolling processes significantly affects the anisotropy of recrystallized material. The recrystallization textures produced in the ASR process improve the normal anisotropy, whereas the in-plane anisotropy does not benefit significantly from the ASR process. Results of crystal plasticity calculations show that an improved normal anisotropy in asymmetrically rolled sheets (anti r = 0.77) ensures an increased limiting drawing ratio of {approx} 2.11, which is beneficial for formability. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Sidor, Jurij J. [Ghent University, Dept. of Materials Science and Engineering Technologiepark 903, 9052 Gent (Belgium); Petrov, Roumen H.; Kestens, Leo A.I. [Ghent University, Dept. of Materials Science and Engineering Technologiepark 903, 9052 Gent (Belgium); Delft University of Technology, Dept. of Materials Science and Engineering Mekelweg 2, 2628 CD, Delft (Netherlands)

2011-10-15

241

Creation of nanostructured composite modifiers for aluminium alloys  

International Nuclear Information System (INIS)

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

242

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

243

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

244

Anodic oxidation and dielectric behaviour of aluminium-niobium alloys  

Energy Technology Data Exchange (ETDEWEB)

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 Nb{sub 2}O{sub 5} and Al{sub 2}O{sub 3} in proportion to the alloy composition. Xenon marker experiments indicated their growth through migration of the Nb{sup 5+}, Al{sup 3+} and O{sup 2-} species, with cation transport numbers, in the range 0.31-0.35, and formation ratios, in the range 1.35-1.64 nm V{sup -1}, intermediate between those of anodic alumina and anodic niobia. Al{sup 3+} ions migrate slightly faster than Nb{sup 5+} 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 Nb{sub 2}O{sub 5} into anodic alumina increases the dielectric constant from about 9 to the range 11-22 for the investigated alloys.

Sa, A.I. de [DMTP/Electroquimica de Materiais, Instituto Nacional de Engenharia Tecnologia e Inovacao, Paco do Lumiar, 22, 1649-038 Lisbon (Portugal); Rangel, C.M. [DMTP/Electroquimica de Materiais, Instituto Nacional de Engenharia Tecnologia e Inovacao, Paco do Lumiar, 22, 1649-038 Lisbon (Portugal); Lu, Q. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom); Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)]. E-mail: p.skeldon@manchester.ac.uk; Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Manchester M60 1QD (United Kingdom)

2006-08-15

245

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 evaperties 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

246

Fabrication of MEMS components using ultrafine-grained aluminium alloys  

International Nuclear Information System (INIS)

A novel process for the fabrication of a microelectromechanical systems (MEMS) metallic component with features smaller than 10 µm and high thermal conductivity was investigated. This may be applied to new or improved microscale components, such as (micro-) heat exchangers. In the first stage of processing, equal channel angular pressing (ECAP) was employed to refine the grain size of commercial purity aluminium (Al-1050) to the ultrafine-grained (UFG) material. Embossing was conducted using a micro silicon mould fabricated by deep reactive ion etching (DRIE). Both cold embossing and hot embossing were performed on the coarse-grained and UFG Al-1050. Cold embossing on UFG Al-1050 led to a partially transferred pattern from the micro silicon mould and high failure rate of the mould. Hot embossing on UFG Al-1050 provided a smooth embossed surface with a fully transferred pattern and a low failure rate of the mould, while hot embossing on the coarse-grained Al-1050 resulted in a rougher surface with shear bands.

247

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

248

Fabrication of MEMS components using ultrafine-grained aluminium alloys  

Science.gov (United States)

A novel process for the fabrication of a microelectromechanical systems (MEMS) metallic component with features smaller than 10 µm and high thermal conductivity was investigated. This may be applied to new or improved microscale components, such as (micro-) heat exchangers. In the first stage of processing, equal channel angular pressing (ECAP) was employed to refine the grain size of commercial purity aluminium (Al-1050) to the ultrafine-grained (UFG) material. Embossing was conducted using a micro silicon mould fabricated by deep reactive ion etching (DRIE). Both cold embossing and hot embossing were performed on the coarse-grained and UFG Al-1050. Cold embossing on UFG Al-1050 led to a partially transferred pattern from the micro silicon mould and high failure rate of the mould. Hot embossing on UFG Al-1050 provided a smooth embossed surface with a fully transferred pattern and a low failure rate of the mould, while hot embossing on the coarse-grained Al-1050 resulted in a rougher surface with shear bands.

Qiao, Xiao Guang; Gao, Nong; Moktadir, Zakaria; Kraft, Michael; Starink, Marco J.

2010-04-01

249

Monitoring precipitation kinetics in heat treatable aluminium alloys using in-situ resistivity in Gleeble thermomechanical simulator  

OpenAIRE

A conventional way to determine precipitation kinetics in heat treatable aluminium alloys is to monitor the associated solute loss by in-situ resistivity. A Gleeble machine is used to perform so called isothermal quenching (IQ) resistivity measurements. IQ consists in quenching the alloy down to a given temperature and holding it at this temperature. The results are validated against measurements performed with a classical four-points method using continuous current on the same alloy.

Chobaut, Nicolas; Carron, Denis; Drezet, Jean-marie

2014-01-01

250

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

Science.gov (United States)

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

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

2007-04-01

251

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

International Nuclear Information System (INIS)

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

252

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

Science.gov (United States)

We present a method to fabricate a super-hydrophobic surface with a self-healing ability on an aluminium alloy substrate. The coatings are obtained by combining a two-step process (first, the substrate is immersed in a solution of HCl, HF and H2O, and then in boiling water) and succeeding surface fluorination with a solution of poly(vinylidene-fluoride-co-hexafluoropropylene) and a fluoroalkyl silane. The morphological features and chemical composition were studied by scanning electron micrometry and energy-dispersive X-ray spectroscopy. The prepared super-hydrophobic aluminium surfaces showed hierarchical structures forming pores, petals and particles with a contact angle of 161° and a sliding angle of 3°.

Wang, Yang; Wei Liu, Xiao; Zhang, Hai Feng; Zhou, Zhi Ping

2015-04-01

253

Microstructure and wear behaviour of aluminium alloys containing embedded nanoscaled lead dispersoids  

International Nuclear Information System (INIS)

We report the early stage friction and wear characteristics of aluminium containing nanosized lead dispersions. The nanocomposite was produced by rapid solidification. The experimental results indicate a significant decrease in friction and wear rate in comparison to its coarse grained counterparts. We show that the observed results suggest an adhesive type of wear mechanism. However, increase in hardness due to refinement of the aluminium grains cannot quantitatively rationalize the results. We explore and discuss the role of nanoscaled lead particles and the mass transport between the sample and counterface via mechanical alloying, in the formation of tribolayers affecting the tribological properties. The plane view and cross-sectional transmission electron microscopy reveals significant elongation as well as coarsening of the lead particles during the process of wear. We attempt to understand these results in the framework of moving dislocations and their assistance to the mass transport among the dispersed lead particles

254

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

Science.gov (United States)

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

Rittapai, Apiwat; Kajornchaiyakul, Julathep; Harniratisai, Choltacha

2014-01-01

255

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

256

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

OpenAIRE

The usage of aluminium and its alloys have increased in many applications and industries over the decades. The automotive industry is the largest market for aluminium castings and cast products. Aluminium is widely used in other applications such as aerospace, marine engines and structures. Parts of small appliances, hand tools and other machinery also use thousands of different aluminium castings. The applications grow as industry seeks new ways to save weight and improve performance and rec...

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

2011-01-01

257

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

258

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

259

Mechanical metallurgy of aluminium alloys for the beverage can  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

260

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

OpenAIRE

The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ) composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP) and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried ou...

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

2012-01-01

261

A metallurgical study of aluminium alloys used as aircraft components  

Energy Technology Data Exchange (ETDEWEB)

The effects of heat treatment on morphologies and microstructures of Al 2024 and Al 7050 alloys, used as aircraft components, were studied by metallographic techniques. Light microscopy (LM) and quantitative image analysis were used to characterize the precipitate dispersion and morphology for these alloys. The application of the scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) combined techniques for studying these multiphase systems makes it possible to distinguish and quantify the different phases in the surface structure. X-ray diffraction also permitted a qualitative comparison of the structures before and after heat treatments. (orig.) [German] Die Auswirkungen der Waermebehandlung auf die Morphologien und die Gefuege der Legierungen Al 2024 und Al 7050 bei der Verwendung als Flugzeugbauteile wurden mit metallographischen Verfahren untersucht. Lichtmikroskopie (LM) und quantitative Bildanalyse wurden zur Charakterisierung der Ausscheidungsverteilung und der Morphologie fuer diese Legierungen eingesetzt. Rasterelektronenmikroskopie (REM) und energiedispersive Roentgenspektroskopie (EDS) als kombinierte Verfahren zur Untersuchung dieser Multiphasensysteme ermoeglichten die Unterscheidung und Quantifizierung der unterschiedlichen Phasen in der Oberflaechenstruktur. Der Einsatz der Roentgenbeugung erlaubte auch einen qualitativen Vergleich der Strukturen vor und nach den Waermebehandlungen. (orig.)

Nakazato, R.Z.; Codaro, E.N.; Horovistiz, A.L.; Hein, L.R.O. [Dept. de Materiais e Tecnologia, Faculdade de Engenharia - UNESP, Guarantingueta, SP (Brazil)

2001-02-01

262

Feasibility of aluminium nitride formation in aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

The feasibility of forming aluminum nitride by in situ reactive nitrogen gas injection into molten aluminum alloys has been evaluated both analytically and experimentally over the temperature range from 700 to 1500 C. It is shown that aluminum nitride can be melt formed in the presence of Mg and Si, with nitrogen and/or ammonia as the reactive gases at temperature above 1100 C. In this role, magnesium serves as a catalyst. Magnesium nitride is first formed in the vapor phase by the reaction of vaporized magnesium and nitrogen gas, followed by incorporation of magnesium nitride particles into the molten aluminum. Via an in situ substitution reaction, aluminum nitride forms between magnesium nitride and aluminum. Up to 17 wt.% aluminum nitride in an aluminum alloy has been formed with an average reinforcement size of 3 {mu}m. The potential for this process permits economical liquid phase processing of aluminum nitride-aluminum metal matrix composite with nitrogen gas injection for structural, thermal and wear applications. ((orig.))

Hou Qinghua [Drexel Univ., Philadelphia, PA (United States). Dept. of Chem. Eng.; Mutharasan, R. [Drexel Univ., Philadelphia, PA (United States). Dept. of Chem. Eng.; Koczak, M. [Department of Materials Engineering, Drexel University, Philadelphia, PA 19104 (United States)

1995-06-01

263

Pressure vessel type aluminium alloy LNG tank; Atsuryoku yoki katashiki aluminium gokin LNG tank  

Energy Technology Data Exchange (ETDEWEB)

Aluminum alloy spherical tanks for use aboard LNG carriers are introduced, for which an application of the pressure vessel type is explained. The report describes the application in the order mentioned below. Described first are the technological tasks involving the LNG cargo and LNG tanks, advantage of the spherical type over various LNG tanks developed so far, methods for confirming the reliability of spherical tanks, and the construction of spherical tanks. The most important among the technological tasks to be dealt with is the measure to counter low temperatures. High reliability has to be sustained for the vessel and tanks in the presence of various loads under rigorous navigating conditions. As for the geometry of tanks, the spherical type is now replacing the square type. The spherical type is formed by bending flat plates, not supported by skeleton, and the spherical surface withstands the LNG load thanks to the membrane force. Since the membrane force is distributed widely and moderately in this case, the spherical surface members all work efficiently. As for tank reliability confirmation, characteristics of the 5083-0 parent material and welded sections, their strength at low temperatures in particular, have already been established. 7 refs., 7 figs.

Itoyama, N. [Sky Aluminium Co. Ltd., Tokyo (Japan)

1998-05-25

264

Analytic and experimental study for light alloy aluminium panels under compression  

Directory of Open Access Journals (Sweden)

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

A. Fayza

2007-11-01

265

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

266

Influence of quench delay time on the corrosion behavior of aluminium alloy 2024  

Energy Technology Data Exchange (ETDEWEB)

The corrosion behavior of aluminium alloys is largely influenced by the microstructure, particularly by the shape, size, and chemical composition of the intermetallic particles. Samples of AA2024-T3 have been heat treated, varying the value of the quench delay time to induce differences in the microstructure of the alloy. The samples were investigated both electrochemically, through corrosion potential monitoring and potentiodynamic measurements, and metallurgically, by means of optical microscopy, scanning electron microscopy (SEM) and EDS analysis. The samples showed corrosion behavior clearly correlated with the type of microstructure. Two kinds of particles were identified in the samples treated with a low quench delay time: the round shaped Al-Cu-Mg precipitates, and the irregularly shaped Al-Cu-Mn-Si-Fe precipitates. When the quench delay time increases complicated shell-shaped particles, with differences in chemical composition between the core and the surface layer, are formed. The presence of these shell-shaped particles causes the corrosion mechanism of the 2024 aluminium alloy to change from general to localized. (orig.)

Campestrini, P.; Rooijen, H.W. van; Westing, E.P.M. van [Netherlands Inst. for Met. Res., Delft (Netherlands); Wit, J.H.W. de [TU Delft, Faculty of Materials Science, Delft (Netherlands)

2000-09-01

267

Corrosion Characteristics and Kinetics of Zircaloys and Aluminium Alloys  

International Nuclear Information System (INIS)

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

268

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

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

Marina Fuser Pillis

2008-09-01

269

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 n 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)

270

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

Energy Technology Data Exchange (ETDEWEB)

An X-ray diffractometric method has been developed for determination of corundum ({alpha}-Al{sub 2}O{sub 3}), spinel (MgAl{sub 2}O{sub 4}) 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).

Iwatsuki, Masaaki; Sagawa, Kunihiro; Fukasawa, Tsutomu [Yamanashi Univ., Kofu (Japan). Faculty of Engineering; Kitamura, Teruo

1995-02-01

271

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)

272

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

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

K. Mroczka

2008-10-01

273

SOLIDIFICATION CHARACTERISTIC OF TITANIUM CARBIDE PARTICULATE REINFORCED ALUMINIUM ALLOY MATRIX COMPOSITES  

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

N. FATCHURROHMAN

2012-04-01

274

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

International Nuclear Information System (INIS)

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

275

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

Energy Technology Data Exchange (ETDEWEB)

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

Rahman, A.B.M. Mujibur; Kumar, Sunil [Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095 (Australia); Gerson, Andrea R. [Applied Centre for Structural and Synchrotron Studies, University of South Australia, Mawson Lakes Campus, Mawson Lakes, SA 5095 (Australia)], E-mail: Andrea.Gerson@unisa.edu.au

2010-06-15

276

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)

277

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)

278

Status and perspectives on n-type silicon solar cells with aluminium-alloyed rear emitter  

OpenAIRE

This study summarises a detailed characterisation of structural and electrical properties of full-area and local aluminium-doped p+ Si (Al-p+) regions alloyed from screen-printed pastes for the application as rear emitters in n-type silicon solar cells. We discuss the impact of the Al doping profile depth on the saturation current density for non-passivated and surface-passivated full-area Al-p+ emitters and show the prerequisites for an effective passivation. The influence of a modified Al p...

Schmiga, C.; Rauer, M.; Ru?diger, M.; Glatthaar, M.; Glunz, S. W.

2012-01-01

279

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

OpenAIRE

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

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

1995-01-01

280

Friction Stir Processing of an AlSi6Cu4 cast aluminium alloy  

OpenAIRE

The present paper deals with the Friction Stir Processing (FSP) of an AlSi6Cu4 cast aluminium alloy. The emphasis was placed on thedetermination of an influence FSP parameters and the torque action on the tool. It was found that an increase in rotational speed of the tool causes a decrease in the torque. Simultaneously, the results showed that an increase in travelling speed of the tool brings about an increase in the torque. The metallographic examination of the processed surface layer of th...

St We?glowski, M.; Dymek, S.

2011-01-01

281

Parametric study of friction stir spot welding of aluminium alloy 5754  

OpenAIRE

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

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

2014-01-01

282

A comparative assessment of crystallite size and lattice strain in differently cast A356 aluminium alloy  

Science.gov (United States)

In this investigation, A356 aluminium alloy has been prepared by different routes viz. gravity casting, rheo pressure die casting (RPDC) and RPDC with T6 heat treatment. X-ray diffraction studies of these samples have been done in the scanning range of 20 – 90°. X-ray peak broadening analysis has been used to estimate the crystallite size and lattice stain, in all the samples. The sample prepared by RPDC with T6 treatment has comparatively smaller crystallite size and lesser lattice strain than gravity cast and RPDC samples.

Mishra, S. K.; Roy, H.; Lohar, A. K.; Samanta, S. K.; Tiwari, S.; Dutta, K.

2015-02-01

283

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

Science.gov (United States)

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

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

284

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

285

Development and testing of one-turn resistive structures of aluminium alloy vacuum vessel for reacting plasma experiment  

International Nuclear Information System (INIS)

R-tokamak is a low radioactive D-T experimental device now in the planning stage. The vacuum vessel has a D-shaped thick shell make of aluminium alloy. The development of toroidal one-turn resistive structures of the aluminium alloy vessel is one of the crucial design subjects for R-tokamak. There exist two possible ways to obtain toroidal one-turn resistive structures, i.e. insulating seal joints and bellows. The results of the development and testing of these two types of one-turn resistive structures are described. (author)

286

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

International Nuclear Information System (INIS)

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

287

Supersonic laser spray of aluminium alloy on a ceramic substrate  

International Nuclear Information System (INIS)

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

288

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

289

The inhibition effect of mad Honey on corrosion of 2007-type aluminium alloy in 3.5% NaCl solution  

Scientific Electronic Library Online (English)

Full Text Available The inhibition effect of mad honey on corrosion of 2007-type aluminium alloy in 3.5% NaCl solution was investigated by Tafel extrapolarisation (TP), electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). All the studied parameters exhibited good anti- [...] corrosive properties against corrosion of 2007-type aluminium alloy in the test solution; the corrosion rates decreased with the increase of the mad honey concentration. The surface morphology of the alloy was examined under scanning electron microscopy (SEM) in the absence and presence of the inhibitor. The inhibitory adsorption processes of mad honey on the 2007-type aluminium alloy surfaces conformed to the Langmuir adsorption isotherm.

Husnu, Gerengi; Haydar, Goksu; Pawel, Slepski.

2014-02-01

290

Fretting wear of a fine particulate reinforced aluminium alloy matrix composite against a medium carbon steel  

Energy Technology Data Exchange (ETDEWEB)

Particulate reinforced aluminium alloy matrix composites, produced by a powder metallurgy route, can show improved specific properties, including elastic modulus and tensile and fatigue strenght, over monolithic alloys. However, these materials are difficult to join using metallurgical processes without impinging on their mechanical performance. Mechanical fasteners or adhesives, which are normally used to join these materials, can result in fretting wear problems under vibration and fatigue regimes. The fretting wear performance of a 2124 Al-Cu-Mg alloy reinforced with 17 vol.% of 3 {mu}m silicon carbide particulate is compared with an equivalent monolithic 2024 Al-Cu-Mg alloy, both in the T4 condition, when tested against a cold-worked medium carbon steel. During the early stages of fretting the composite show significant advantages, reducing the degree of debris transfer to the counterface. However, as fretting progresses the performance of the composite becomes inferior to that of the equivalent monolithic alloy. At high numbers of fretting cycles the degree of direct contact between the fretting faces is minimal and wear progresses via layers of debris. This behaviour is interpreted in terms of the transfer and loss of debris as wear progresses, involving deformation-adhesion, delamination, abrasion, debris oxidation and attrition of the reinforcing particles. (orig.)

McColl, I.R. [Dept. of Materials Engineering and Materials Design, Univ. of Nottingham (United Kingdom); Harris, S.J. [Dept. of Materials Engineering and Materials Design, Univ. of Nottingham (United Kingdom); Spurr, G.J. [Dept. of Materials Engineering and Materials Design, Univ. of Nottingham (United Kingdom)

1996-09-01

291

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

Directory of Open Access Journals (Sweden)

Full Text Available Electrochemical and gravimetric measurements were used to examine the effects of neodymium and gadolinium additions on the galvanic corrosion behaviour of AM50 and AZ91D magnesium alloys coupled to A 570 Gr 36 carbon steel and AA2011-AA6082 aluminium alloys. Rare earth modified alloys showed Al2Nd/Al2Gd and Al-Mn-Nd/Al-Mn-Gd intermetallics, reduced area fraction of ?-Mg17Al12 phase and increased corrosion resistance due to increased surface passivity and suppression of micro-galvanic couples. Neodymium and gadolinium additions improved the galvanic corrosion resistance of AM50 alloy, but were less effective in case of the AZ91D alloy. The AA6082 alloy was the most compatible material and the AA2011 alloy was the least compatible.Se emplearon medidas electroquímicas y gravimétricas para examinar el efecto de la adición de neodimio y gadolinio en el comportamiento a la corrosión galvánica de las aleaciones AM50 y AZ91D en contacto con acero al carbono A 570 Gr 36 y aleaciones de aluminio AA2011 y AA6082. Las aleaciones modificadas con tierras raras mostraron intermetálicos Al2Nd/Al2Gd y Al-Mn-Nd/Al-Mn-Gd, menor fracción de fase ?-Mg17Al12 y un incremento de la resistencia a la corrosión debido al aumento de la pasividad de la superficie y a la eliminación de micro pares galvánicos. Las adiciones de neodimio y gadolinio mejoraron la resistencia a la corrosión galvánica de la aleación AM50, pero fueron menos efectivas en el caso de la aleación AZ91D. La aleación AA6082 fue el material más compatible y la aleación AA2011 el menos compatible.

Mohedano, Marta

2014-03-01

292

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.

293

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

International Nuclear Information System (INIS)

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 alloys during hot working at low and intermediate strains was described by a new model for the accumulation and annihilation by climb of geometrically necessary dislocations at non-deformable precipitates. Strain hardening behaviour at high strains correlated with the reduction in spacing between grain boundary precipitates. (orig.)

294

Triazole and thiazole derivatives as corrosion inhibitors for AA2024 aluminium alloy  

International Nuclear Information System (INIS)

The 1,2,4-triazole, 3-amino-1,2,4-triazole, benzotriazole and 2-mercaptobenzothiazole were evaluated in the present work as corrosion inhibitors for protection of the 2024 aluminium alloy in neutral chloride solutions. The corrosion protection performance was investigated by means of DC polarization and electrochemical impedance spectroscopy (EIS). Scanning Kelvin probe force microscopy (SKPFM) and atomic force microscopy (AFM) were used to study the evolution of the Volta potential distribution and the surface topography during corrosion tests. The results show that all inhibitors under study confer corrosion protection to the AA2024 alloy forming a thin organic layer on the substrate surface. Benzotriazole and 2-mercaptobenzothiazole offer better corrosion protection in comparison with the other two. The inhibitors studied act decreasing the rate of both the anodic and cathodic processes. In the latter case the dealloying of the copper-reach particles is hindered, slowing down the oxygen reduction

295

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

International Nuclear Information System (INIS)

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

296

The influence of surface treatment on filiform corrosion resistance of painted aluminium alloy sheet  

International Nuclear Information System (INIS)

Filiform corrosion of AA 5005 H14 aluminium alloy sheet has been investigated. Painted and scribed panels, with different surface treatments, were inoculated in HCl and exposed in a constant humidity cabinet maintained at 40 deg. C and 75-85% RH for 1000 h. After exposure, the panels were examined by optical and electron microscopy. It is evident that filiform corrosion susceptibility is determined largely by the near-surface microstructure. Heavily deformed layers, comprising oxide-decorated fine grains and dispersoids on as-rolled and mechanically ground alloy surfaces, are readily susceptible to filiform corrosion. Removal of these deformed layers, by caustic etching and acid cleaning, results in a high filiform corrosion resistance. On such surfaces, underfilm corrosion progresses by localized corrosion of the substrate; with comparatively slowly growing filaments propagating by repeated blistering of the overlying lacquer

297

Effect of the temperature and the chlorine pressure, over the aluminium chlorides obtained by direct chlorination of the 6061 alloy  

International Nuclear Information System (INIS)

The aluminium chloride is synthesized by direct chlorination of aluminium, in agreement with the following reaction: Al(s) + 3/2 Cl2 AlCl3 (s,g).The present work focuses on the preparation of aluminium chlorides by two methods: (a) Chlorination of 6061 aluminium alloy with gaseous chlorine in sealed containers, filled with different pressures of gas, from 0.8 to 74 Kpa and in the range of temperature between 2000 and 5000C.(b) Chlorination of the same alloy in chlorine flow between 1500 and 4000C.In the sealed systems, the hexahydrated aluminium trichloride predominated over the anhydrous form. For pressures lower than 14 Kpa and temperatures under 2500C, the chloride didn't appear.The residues were rich in aluminium, chlorine and magnesium.In the other systems, the anhydrous chloride was found in the areas of the reactor of temperatures above 1000C, for all the thermal treatments. The waste was composed by CrCl3 and AlCl3.6H2O.The influence of the chlorine pressures and the heating temperature over the characteristics of the product, was studied.The characterization techniques were x-ray diffraction and energy dispersive spectroscopy, and the evolution of the structure was followed by scanning electron microscopy

298

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

Science.gov (United States)

Cold spraying is increasingly being used for reconstruction or repair of damaged aluminium alloy components, especially in the aviation industry. Both thin (coatings are necessary to achieve dimensional recovery of such components. Thin and above all thick coatings can be deposited in a single pass (single layer) or in several passes (multi-pass), resulting in different thermal and stress effects in the component and the coating itself. The thermal input, the amount and type of residual stresses and the porosity affect various characteristics such as adhesion, crack propagation and mechanical properties of the coating. In this study, two sets (single- and multi-pass) of aluminium alloy (AA6061) coatings with different thicknesses (0.5 mm to 2 mm) were deposited onto AA6061 substrates and compared using metallographic and fractographic analyses, four-point bending testing, residual stress analysis and Vickers microhardness indentation. Finally, the coating adhesion and cohesion were measured using the standard ASTM-C633 adhesion test and tubular coating tensile test. This study demonstrates that the single-layer strategy results in greater adhesion and lower porosity, while multilayer coatings have higher elastic modulus. Independent of the strategy, the compressive residual stress decreases as a function of coating thickness.

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

2014-12-01

299

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

International Nuclear Information System (INIS)

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

300

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

301

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

302

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

International Nuclear Information System (INIS)

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

303

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

OpenAIRE

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

304

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

305

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

OpenAIRE

Extensive solidification simulations are conducted using finite difference method on an aluminium alloy casting. Orthogonal experimental array layout is considered for running experimental simulations. Microstructural parameter Secondary Dendrite Arm Spacing (SDAS) at three different locations was predicted as response variable, through solidification simulations by varying the process parameters. The input process variables are pouring temperature, insulation on riser and chill volume heat c...

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

2010-01-01

306

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

Czech Academy of Sciences Publication Activity Database

7 2013, ?. 7 (2013), s. 53-64. ISSN 1802-680X Grant ostatní: Interní podpora AV ?R(CZ) M100411204 Keywords : LELM * stress intensity tensor * constraint * aluminium alloy * plane strain * plane stress Subject RIV: JL - Materials Fatigue, Friction Mechanics

Seitl, Stanislav; Huta?, Pavel; García, T.; Canteli, A.

307

Microstructure of friction stir welding of aluminium alloy to magnesium alloy  

International Nuclear Information System (INIS)

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

308

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

OpenAIRE

Investigations into the effects of magnesium content and cooling rates on the mechanical properties of aluminium-magnesium alloys refined with titanium-boride master alloy was conducted. Experimental samples were produced from melt with Mg content ranging from 0% to 8%, poured and cooled in air, water and oil. Standard sample dimensions were produced for tensile and hardness tests. It was observed that both the Mg content and the cooling rate affect the mechanical properties; elongation (duct...

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

2012-01-01

309

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

310

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

International Nuclear Information System (INIS)

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

311

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

International Nuclear Information System (INIS)

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

312

Study of Microstructural Defect Parameters in Vanadium-Aluminium Alloys using Warren-Averbach Method and Modified Rietveld Technique  

Science.gov (United States)

Detailed X-ray diffraction line profile analysis using Warren-Averbach method and modified Rietveld technique has been performed on the X-ray diffraction profile of body centered cubic vanadium-base aluminium alloys of nominal compositions in wt % as V-26% Al (Alloy I), V-24% Al (Alloy II), V-20% Al (Alloy III) and V-18% Al (Alloy IV). The microstructural parameters such as coherent domain size, microstrain within the domains and compound faults were evaluated in the alloys by applying Fourier line shape analysis. The Fourier analysis has been done taking silicon as standard. The growth fault parameter (? ) has been observed to be either negligibly small or negative. This shows that growth faults are absent in this bcc system. It has also been observed that the spacing fault (? \\varepsilon ) is totally absent in the system because the values are negative. The faulting parameter (1.5 ? + ? ) and deformation stacking fault ? obtained from these analyses are however, not negligible.

Ghosh, J.; Chattopadhayay, S. K.; Meikap, A. K.; Chatterjee, S. K.; Pradhan, S. K.

2005-09-01

313

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 threse 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)

314

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

Directory of Open Access Journals (Sweden)

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

?. Kaczmarek

2009-12-01

315

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

International Nuclear Information System (INIS)

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

316

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

Energy Technology Data Exchange (ETDEWEB)

For thixoforming (semi-solid processing) it is necessary to have a fine globular microstructure in a semi-solid range. Here this has been obtained for 7075 aluminium alloy by addition of modifying agents: 0.5 weight % of scandium and zirconium. The thixoforming process was carried out at 632 °C which gave about 23 volume % of liquid phase. The microstructure of the thixo-formed part (a rotor) consisted of globular grains surrounded by precipitates of secondary phase. The average hardness of thixo-formed parts was 105 HV{sub 5} and the tensile strength 300 MPa. T6 heat treatments were performed with solutionisation at 450 °C for 30 min and 10 h. In both cases the ageing time was set as 18 h at 120 °C. The heat treatments led to an increase in average tensile strength up to 495 MPa. Transmission Electron Microscopy (TEM) analysis enabled the identification of precipitates of the metastable dispersoids of L1{sub 2}–Al{sub 3} (Zr, Sc) and ?? (MgZn{sub 2}) phases in the alloy after the thixoforming and T6 treatment. The measurements of rheological properties of 7075Al alloy with Sc and Zr additions in the semi-solid range indicated an increase of particle size and spheroidization leading to an observable decrease of viscosity during isothermal shearing. A shear rate jump experiment showed that with increasing shear rate the viscosity rapidly falls.

Rogal, ?., E-mail: l.rogal@imim.pl [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Dutkiewicz, J. [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Atkinson, H.V. [The University of Leicester, Department of Engineering University Road, Leicester, LE1 7RH (United Kingdom); Lity?ska-Dobrzy?ska, L.; Czeppe, T. [Institute of Metallurgy and Materials Science of the Polish Academy of Sciences, 25 Reymonta St., 30-059 Krakow (Poland); Modigell, M. [RWTH Aachen—Department of Mechanical Process Engineering, 55 Templergraben St., Aachen (Germany)

2013-09-15

317

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

Science.gov (United States)

The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO4 electrolytes was examined by potentiodynamic polarisation, potentiostatic polarisation and scanning electron microscopy. Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation. The large size of the exposed carbon fibres on the side region is responsible for a higher cathodic current density than the front region in the NaCl electrolyte. The deposition of copper on the front surface of composite confirmed that the significantly higher cathodic current resulted from the exposure of the fibres to the NaCl electrolyte. Galvanic coupling between the composite and individual aluminium alloys (AA7075-T6 and AA1050) was used to measure galvanic potentials and galvanic current densities. The highly alloyed AA7075-T6 alloy and its high population density of cathodic sites compared to the AA1050 acted to reduce the galvanic effect when coupled to the composite front or side regions.

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

2014-09-01

318

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

International Nuclear Information System (INIS)

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

319

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

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of this work is to report the effect of the high energy milling processes, on fabrication ofaluminium matrix composite powders, reinforced with a homogeneous dispersion of the intermetallic Ti3Alreinforcing particles.Design/methodology/approach: MA process are considered as a method for producing composite metalpowders with a controlled fine microstructure. It occurs by the repeated fracturing and re-welding of powdersparticles mixture in a highly energetic ball mill.Findings: Mechanical alloying, applied for composite powder fabrication, improves the distribution of theTi3Al intermetallic reinforcing particles throughout the aluminium matrix, simultaneously reducing their size.Observed microstructural changes influence on the mechanical properties of powder particles.Research limitations/implications: Contributes to the knowledge on composite powders production via MA.Practical implications: Gives the answer to evolution of the powder production stages, during mechanicalalloying and theirs final properties.Originality/value: Broadening of the production routes for homogeneous particles reinforced aluminium matrixcomposites.

M. Adamiak

2008-12-01

320

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

International Nuclear Information System (INIS)

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

321

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

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this work is to analyse the process of friction stir welding (FSW of 3mm thick aluminium plates made of high strength aluminium alloy - 2024 T3, as well as to assess the mechanical properties of the produced joints. FSW is a modern procedure which enables joining of similar and dissimilar materials in the solid state, by the combined action of heat and mechanical work. This paper presents an analysis of the experimental results obtained by testing the butt welded joints. Tensile strength of the produced joints is assessed, as well as the distribution of hardness, micro-and macrostructure through the joints (in the base material, nugget, heat affected zone and thermo-mechanically affected zone. Different combinations of the tool rotation speed and the welding speed are used, and the dependence of the properties of the joints on these parameters of welding technology is determined. [Projekat Ministarstva nauke Republike Srbije, br. TR 34018 i br. TR 35006

Eramah Abdsalam M.

2014-01-01

322

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

Science.gov (United States)

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.; Ali, Aidy; Mahdi, El-Sadiq; Hamouda, A. M.

2011-02-01

323

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

International Nuclear Information System (INIS)

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

324

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

International Nuclear Information System (INIS)

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

325

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

International Nuclear Information System (INIS)

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

326

Microstructural evolution and mechanical properties of oil jet peened aluminium alloy, AA6063-T6  

International Nuclear Information System (INIS)

Grain size refinement by severe surface plastic deformation is one way of improving the surface properties. This paper describes the microstructural evolution due to severe surface plastic deformation by oil jet peening in aluminium alloy, AA6063-T6. Detail characterization of the treated surfaces using X-ray diffraction analysis and transmission electron microscopy revealed the formation of submicron size grains at and near the surface. The nozzle-traveling velocity decides the peening intensity and coverage and affects the surface properties. The specimen peened at low nozzle-traveling velocity exhibited an ultrafine grain size (?210 nm) with high surface hardness (?0.88 GPa), compressive residual stress (-102 ± 7 MPa) and dislocation density. The hardness is high at the surface and the depth of hardened layer is ?400 ?m. Formation of high-density dislocations and associated grain refinement resulted in increased surface hardness. Presence of surface modified layer will be beneficial in improving the fatigue and tribo behavior.

327

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.

328

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-02-18

329

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

International Nuclear Information System (INIS)

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

330

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-05-01

331

Emittance of boehmite and alumina films on 6061 aluminium alloy between 295 and 773 K  

International Nuclear Information System (INIS)

The total hemispherical emittance of an oxide film that formed on 6061-T6 aluminium alloy parts in the Tower Shielding Reactor-II at Oak Ridge National Laboratory was measured from 295 to 773 K using an emissometer and/or a calorimeter. The emittance of this film was critically needed for heat transfer calculations in a simulated loss-of-coolant accident of the reactor. X-ray diffraction analysis identified the film as boehmite (Al2O3 x H2O), which dehydrated to alumina (Al2O3) upon heating above 473 K. The measured emittances for the alumina film are in excellent agreement with published values for anodized aluminum films and for bulk alumina. Published values of the emittance of boehmite could not be found for comparison, but evidence is presented that some anodization processes for aluminum yield boehmite and not alumina films

332

Friction Stir Processing of an AlSi6Cu4 cast aluminium alloy  

Directory of Open Access Journals (Sweden)

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

M.St. W?glowski

2011-04-01

333

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-08-15

334

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

Science.gov (United States)

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

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

2012-08-01

335

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

336

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

337

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

International Nuclear Information System (INIS)

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

338

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-09-15

339

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

International Nuclear Information System (INIS)

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

340

Fracture mechanisms of aluminium alloy AA7075-T651 under various loading conditions  

International Nuclear Information System (INIS)

The fracture behaviour of the aluminium alloy AA7075-T651 is investigated for quasi-static and dynamic loading conditions and different stress states. The fracture surfaces obtained in tensile tests on smooth and notched axisymmetric specimens and compression tests on cylindrical specimens are compared to the fracture surfaces that occur when a projectile, having either a blunt or an ogival nose shape, strikes a 20 mm thick plate of the aluminium alloy. The stress state in the impact tests is much more complex and the strain rate significantly higher than in the tensile and compression tests. Optical and scanning electron microscopes are used in the investigation. The fracture surface obtained in tests with smooth axisymmetric specimens indicates that the crack growth is partly intergranular along the grain boundaries or precipitation free zones and partly transgranular by void formation around fine and coarse intermetallic particles. When the stress triaxiality is increased through the introduction of a notch in the tensile specimen, delamination along the grain boundaries in the rolling plane is observed perpendicular to the primary crack. In through-thickness compression tests, the crack propagates within an intense shear band that has orientation about 45o with respect to the load axis. The primary failure modes of the target plate during impact were adiabatic shear banding when struck by a blunt projectile and ductile hole-enlargement when struck by an ogival projectile. Delamination and fragmentation of the plates occurred for both loading cases, but was stronger for the ogival projectile. The delamination in the rolling plane was attributed to intergranular fracture caused by tensile stresses occurring during the penetration event.

341

Evaluation of the load-carrying capacity of hard coatings deposited onto a 7075-T6 aluminium alloy  

International Nuclear Information System (INIS)

In the present work, the effect of the thickness of an electroless NiP load-support interlayer coating, on the initiation and development of plastic deformation in a 7075-T6 aluminium alloy substrate coated with a duplex coatings has been investigated. The duplex system has been obtained by means of the deposition of an electroless Ni-11 wt.% P (EN) onto the aluminium alloy substrate, followed by the deposition of a ZrN film (PVD) on top of the EN coating. The duplex systems that were investigated involved two different EN deposits, with thicknesses of 30 and 60 mm, respectively. The coatings were characterized regarding their morphology, thickness and absolute hardness. Indentation tests with spherical ind enters were performed employing 6 mm diameter WC-6Co balls and normal loads of 10,15, 25,50 and 75 N. All the indentations were modeled by means of the Elastic 2.1. code, in order to determine the through-thickness von Misses effective stress profile of the samples and the critical load for the initiation of the plastic deformation of the aluminium alloy substrate. the experimental results have been validate by means of such a theoretical analysis. it has been determined that the duplex system with an EN interlayer of 30 mm does not constitute a satisfactory load-support interlayer, for the load values employed in the tests. However, for the coated system with an EN interlayer of 60 mm, the critical load for the initiation of plastic deformation in the aluminium alof plastic deformation in the aluminium alloy substrate was found to be?16N, which indicates that such a load-support interlayer avoids the plastic deformation of the substrate at normal loads less than ? 15 N. (Author) 21 refs

342

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.

343

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

Energy Technology Data Exchange (ETDEWEB)

The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010. - Highlights: Black-Right-Pointing-Pointer Through thickness residual stress measurements made on large Al alloy forgings. Black-Right-Pointing-Pointer Residual stress characterised using neutron diffraction and deep hole drilling. Black-Right-Pointing-Pointer Biaxial compressive surface and triaxial subsurface residual stresses. Black-Right-Pointing-Pointer Quench sensitivity of 7075 promotes significant microstructural differences to 7010. Black-Right-Pointing-Pointer When precipitation is accounted for, residual stress in both forgings are similar.

Robinson, J.S., E-mail: jeremy.robinson@ul.ie [Materials and Surface Science Institute, University of Limerick (Ireland); Tanner, D.A. [Materials and Surface Science Institute, University of Limerick (Ireland); Truman, C.E. [Department of Mechanical Engineering, University of Bristol (United Kingdom); Paradowska, A.M. [ISIS Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); Wimpory, R.C. [Helmholtz Centre Berlin for Materials and Energy, Hahn Meitner Platz 1, Berlin (Germany)

2012-03-15

344

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

Scientific Electronic Library Online (English)

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

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

2003-08-01

345

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

International Nuclear Information System (INIS)

The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. S forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010. - Highlights: ? Through thickness residual stress measurements made on large Al alloy forgings. ? Residual stress characterised using neutron diffraction and deep hole drilling. ? Biaxial compressive surface and triaxial subsurface residual stresses. ? Quench sensitivity of 7075 promotes significant microstructural differences to 7010. ? When precipitation is accounted for, residual stress in both forgings are similar.

346

Impact of M2-Hss Tool Pin Profile in Fsw Welded Joints On Mechanical Properties Of Aa7075-T6 Aluminium Alloy  

OpenAIRE

Friction stir, “welding is a solid state joining process and is widely being considered for aluminium alloys. The main advantage of FSW is the material that is being welded undergoes only localized changes. The welding parameter and tool pin profile play a major role in deciding the weld quality. In this work an effort has been made to analyze microstructure of aluminium AA 7075-T6 alloy. Three different tool profiles (Taper Threaded, cylindrical and square) have been used t...

Venugopal S; Mahendran, G.

2014-01-01

347

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2003-12-20

348

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

349

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

350

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

351

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

352

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

353

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

Science.gov (United States)

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

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

2004-01-01

354

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

International Nuclear Information System (INIS)

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

355

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

356

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

357

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

358

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

359

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

360

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

Energy Technology Data Exchange (ETDEWEB)

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 {beta} 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 {alpha} increases by the addition of aluminium as solute and hence lowers its stacking fault energy.

Ghosh, J. [National Institute of Technology, Durgapur 713 209 (India)], E-mail: jiten@cgcri.res.in; Chattopadhayay, S.K.; Meikap, A.K.; Chatterjee, S.K. [National Institute of Technology, Durgapur 713 209 (India)

2008-04-03

361

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

OpenAIRE

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 damag...

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

2012-01-01

362

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

OpenAIRE

Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA2014/7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are ta...

Rajasuthan, K.; , S.Raja2

2014-01-01

363

Effect of Friction Stir Welding on Mechanical Properties of Dissimilar Aluminium Aa6061 and Aa2014 Alloy Joints  

OpenAIRE

In present study, Dissimilar Friction Stir Butt Welds made of 2014 and 6061 Aluminium alloys were performed with various welding parameter. The present study deals with the influence of Square Profile Pin on Friction Stir Welded joint. FSW parameter such as Tool Rotational Speed, Welding Speed and Axial Force plays a significant role in the assessment of mechanical properties. Using ANOVA and Signal to Noise ratio, influence of FSW process parameters is evaluated and optimum w...

Purushotham, P.

2014-01-01

364

Effects of strain rate on the characteristics of PLC deformation bands for AA5083-H116 aluminium alloy  

OpenAIRE

Abstract An experimental, theoretical and numerical investigation of the Portevin-Le Chatelier (PLC) effect in the aluminium alloy AA5083-H116 is undertaken in this paper. Five different tests at different overall strain rates are carried out on smooth flat specimens in order to exhibit the effects of strain rate on the characteristics of the deformation bands and their propagation. Both digital image correlation and digital infrared thermography are used to capture and characteriz...

Benallal, A.; Berstad, Torod; Borvik, Tore; Hopperstad, Odd Sture; Nogueira Codes, Rodrigo

2009-01-01

365

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

Directory of Open Access Journals (Sweden)

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

Sashikant Janardan Morey

2011-03-01

366

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

OpenAIRE

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

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

2013-01-01

367

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

OpenAIRE

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

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

2011-01-01

368

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

Science.gov (United States)

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

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

2014-12-01

369

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

370

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

DEFF Research Database (Denmark)

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

Daviðsdóttir, Svava; Soyama, Juliano

2011-01-01

371

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

International Nuclear Information System (INIS)

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

372

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

Directory of Open Access Journals (Sweden)

Full Text Available Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA2014/7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are taken into account through boundary conditions for the outward heat flux. Linear FE transient thermal analysis is performed using surface heat source model with Gaussian distribution to compute highest temperature in AA2014 plates. The objective of this project is to simulate the welding process by using the finite element method. After the model is built and verified, the main objective of this project is to study the effects of varying the welding process parameters on the thermo-mechanical responses. In addition to that, the aim of this research is also to find a relationship between welding parameters and the responses of single pass butt welding are evaluated through the finite element analysis of Aluminium Alloy AA2014 and AA7075. The study of this paper covers the Comparative Study of Aluminium Alloy Plate 2014/7075 under the effect of Butt welding process by varying heat input, welding speed on the thermo-mechanical responses of the weldment after cooling down to room temperature.

K.Rajasuthan*

2014-01-01

373

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)

374

Radiation-thermal processes in aluminium alloy D16 during treatment by pulsed plasma and electron beams  

International Nuclear Information System (INIS)

Using the methods of X-ray diffraction analysis, scanning electron microscopy and X-ray spectral microanalysis the influence of pulsed electron and plasma treatment on structure and element composition of commercial aluminium alloy D16 is studied. The differently directed influence of pulsed electron and plasma treatment on the structure of the alloy caused, apparently, by radiation processes of electrons and plasma ions interaction with material is revealed. The role of thermal processes characteristic to pulsed effects is manifested in the formation of mainly fine inclusions of strengthening S-phase of two types which are differ in the degree of enrichment by copper atoms

375

The Effects of Zinc Additions on the Corrosion Susceptibility of Aluminium Alloys in Various Tetraoxosulphate (VI Acid Environments  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of zinc additions on the corrosion behaviour of aluminium alloys in H2SO4 solution of varying concentrations has been investigated. Aluminium-zinc alloys of 1.0, 2.0, 2.5, 3.5 and 4.0% zinc by weight were cast and machined to cuboidal test coupons of initial surface area averaging 12.71 cm2. The coupons were then weighed and immersed into beakers containing 0.5 M and 1.0 M H2SO4 solutions. The set-ups were allowed to stand for six days with a set withdrawn daily for corrosion rate characterization using standard procedures. The results showed that although, the normal corrosion rate profile (for passivating metals of an initial steep rise, then a progressive decline was observed in all the media as the fraction of the solute in the alloy increased, there was severity of attack on the 2.5% Zn alloy. It is concluded that the severity of attack on the 2.5% Zn alloy is due to increased grain boundary concentration possibly implying a maximum solid solubility (solvus line in Al-Zn binary systems within this range.

C.E. Ekuma

2007-01-01

376

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

International Nuclear Information System (INIS)

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

377

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

Energy Technology Data Exchange (ETDEWEB)

The present study embodies the results obtained with iron-aluminium alloys whose composition runs from 0 to nearly 50 atoms per cent aluminium. Conditions of elaboration and transformation have been studied successively, as well as the Young's modulus and the flow stress; the last chapter embodies, a study of the Portevin-le-Chatelier effect in alloys of 40 atoms per cent of aluminium. I) The principal difficulty to clear up consisted in the intergranular brittleness of ordered alloys; this brittleness has been considerably reduced with appropriate conditions of elaboration and transformation. II) The studies upon the Young's modulus are in connection with iron-aluminium alloys; transformation temperatures are well shown up. The formation of covalent bonds on and after 25 atoms per cent show the highest values of the modulus. III) The analysis of variations of the flow stress according to the temperature show some connection with ordered structures, the existence of antiphase domains and the existence of sur-structure dislocations. IV) In the ordered Fe Al domain the kinetics of the Portevin-le-Chatelier effect could be explained by a mechanism of diffusion of vacancies. The role they play has been specified by the influence they exert upon the dislocations; this has led us to the inhomogeneous Rudman order; this inhomogeneous order could explain the shape of the traction curves. (author) [French] Cette etude comporte les resultats obtenus avec des alliages fer-aluminium dont la composition s'etend de 0 a pres de 50 atomes pour cent d'aluminium. Nous avons etudie successivement les conditions d'elaboration et de transformation, le module elastique et la limite elastique; un dernier chapitre est consacre a l'etude du phenomene Portevin-le-Chatelier dans les alliages a 40 atomes pour cent d'aluminium. I) La principale difficulte a resoudre residait dans la fragilite intergranulaire des alliages ordonnes; celle-ci a ete considerablement reduite par des conditions appropriees d'elaboration et de transformation. II) Les etudes de module d'elasticite sont en rapport avec les diagrammes fer-aluminium; les temperatures de transformation sont bien mises en evidence. La formation de liaisons covalentes a partir de 25 atomes pour cent se traduit par des valeurs plus elevees du module. III) L'analyse des variations de la limite elastique en fonction de la-temperature fait apparaitre certaines relations avec les structures ordonnees, la presence de domaines anti-phases et l'existence de dislocations de surstructure. IV) Dans le domaine Fe Al ordonne, la cinetique du phenomene Portevin-le- Chatelier reposerait sur un mecanisme de diffusion lacunaire; nous avons precise leur role par l'influence qu'elles ont sur les dislocations, ce qui nous a conduit a l'ordre inhomogene de Rudman qui pourrait expliquer les crochets observes sur les courbes de traction. (auteur)

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

1966-06-01

378

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

OpenAIRE

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...

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

2013-01-01

379

Ageing Response of Ac4b Aluminium Alloys with 0.01 wt.% Sr Addition Processed Thorough Low Pressure Die Casting  

International Nuclear Information System (INIS)

Common problems found in aluminium components produced through Low Pressure Die Casting (LPDC) process are low hardness with porosity and shrinkage due to different cooling rate. Modification of microstructure by addition of Sr and heat treatment processes are alternatives to solve the problems. This research studied the effect of modification through addition of 0.01 wt % Sr and ageing processes on the microstructure and mechanical properties of AC4B aluminium alloy. The results show that addition of 0.01 wt % Sr modifies silicon structure from acicular into fine and fibrous. This structure is believed to slightly increase the hardness of AC4B aluminium alloy. However, addition of Sr increase porosity that should be carefully handled. Ageing processes increase the hardness of the alloy, in which the higher the ageing temperature, the shorter the time needed to achieve peak hardness, but the lower the peak hardness of the alloy. (author)

380

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-15

381

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

Directory of Open Access Journals (Sweden)

Full Text Available Zirconia coating was produced on aluminium alloy by plasma electrolytic oxidation (PEO. The alkaline electrolyte containing Zr(OHª4 powders was used. The composition and structure of the coating were investigated by XRD, EPMA. The results show that the coating consists of ª«t-ZrO2, ª«m-ZrO2, ª«¦?/SUB>-Al2O3 and ª«¦|/EM>-Al2O3. ª«t-ZrOª2 is the main phase and distributes in outer layer of the coating, however, ª«¦?/EM>-Al2O3 appears in inner layer of the coating. Many micro-particles appear on the coating surface with dimension of ª©1£2¦?ªª. In the process of plasma electrolytic oxidation, Zr(OHª4 powders move and deposite on the mouth of plasma discharge channel under the effect of electric field force, then it is transformed to ZrOª2 by the high temperature of plasma discharge.

XIN Shi-Gang,ZHAO Rong-Gen,DU Hui,SONG Li-Xin

2009-01-01

382

Fatigue Life Recovery in Corroded Aluminium Alloys Using Bonded Composite Reinforcements  

Science.gov (United States)

Bonded composite reinforcements, such as boron/epoxy or carbon/epoxy, are becoming widely used to repair fatigue or stress corrosion cracks in aluminium alloy aircraft components. They also have considerable potential as repairs for corrosion damage, although the non-discrete nature of corrosion damage is a considerable complication. This paper describes studies on bonded repairs of two types of typical corrosion damage, both of which cause a dramatic reduction in fatigue life: a) relatively severe exfoliation and b) relatively minor pitting. Both studies are based on earlier Australian experimental studies on the structural significance of corrosion. In the studies described in this paper, other than the standard surface treatment used to attach the reinforcement no attempt was made to remove the corrosion damage. It is concluded that bonded repairs can provide useful fatigue life recovery even with serious exfoliation damage; however, such repairs should be regarded only as a temporary measure. For permanent and far more effective repairs most of the damage should be removed (ground-out) prior to reinforcement. In contrast, with minor pitting, greater than full life recovery is feasible. This observation also leads to the conclusion that bonded repairs will be tolerant of minor pitting inadvertently left after grind-out. Strain reduction by the reinforcement, as expected, is the major contributor to life extension. However, in the case of minor pitting environmental isolation by the adhesive is probably highly beneficial. Residual stresses in the metal resulting from the composite reinforcement causes some loss in patching efficiency.

Baker, Alan A.

2006-05-01

383

Study of aluminium nitride precipitation in pure Fe-Al-N alloy by thermoelectric power measurements  

Energy Technology Data Exchange (ETDEWEB)

Aluminium nitride (AlN) precipitation in an Fe-Al-N alloy was investigated using thermoelectric power (TEP). The TEP variations due to annealing at high temperature are connected with the solubility of AlN. Analysis of AlN precipitation during annealing in {alpha}-phase enables us to distinguish one range of temperature (500--575 C) corresponding to an activation energy of 60 kcal/mole and another range (575--700 C) corresponding to an activation energy of 50 kcal/mole. From TEM observations, the difference was related to the temperature effect on the nucleation: the first range corresponds to a homogeneous precipitation, while in the second range the nucleation occurs on the dislocations. In steel which also contains carbon and manganese a second stage for long isothermal annealings was observed and was attributed to manganese enrichment of iron carbides. The precipitation at low temperature, and the influence of an initial cold-rolling before annealing on TEP variations were also examined.

Brahmi, A.; Borrelly, R. [INSA de Lyon, Villeurbanne (France). Groupe d`Etudes de Metallurgie Physique et de Physique des Materiaux

1997-05-01

384

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

Science.gov (United States)

Deep surface rolling can introduce deep compressive residual stresses into the surface of aircraft metallic structure to extend its fatigue life. To develop cost-effective aircraft structural repair technologies such as laser cladding, deep surface rolling was considered as an advanced post-repair surface enhancement technology. In this study, aluminium alloy 7075-T651 specimens with a blend-out region were first repaired using laser cladding technology. The surface of the laser cladding region was then treated by deep surface rolling. Fatigue testing was subsequently conducted for the laser clad, deep surface rolled and post-heat treated laser clad specimens. It was found that deep surface rolling can significantly improve the fatigue life in comparison with the laser clad baseline repair. In addition, three dimensional residual stresses were measured using neutron diffraction techniques. The results demonstrate that beneficial compressive residual stresses induced by deep surface rolling can reach considerable depths (more than 1.0 mm) below the laser clad surface.

Zhuang, W.; Liu, Q.; Djugum, R.; Sharp, P. K.; Paradowska, A.

2014-11-01

385

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

Science.gov (United States)

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

Jovovi?, J.

2014-12-01

386

Modelling of liquid metal flow and oxide film defects in filling of aluminium alloy castings  

Science.gov (United States)

The liquid metal flow behaviours in different runner system designs have important effects on the mechanical strength of aluminium alloy castings. In this paper, a new model has been developed which is a two-dimensional program using a finite difference technique and the Marker and Cell (MAC) method to simulate the flow of liquid metal during filling a mould. In the program the Eulerian method has been used for the liquid metal flow, while the Oxide Film Entrainment Tracking Algorithm (OFET) method (a Lagrangian method) has been used to simulate the movement of the oxide film on the liquid metal surface or in the liquid metal flow. Several examples have been simulated and tested and the relevant results were obtained. These results were compared with measured bending strengths. It was found that the completed program was capable of simulating effectively the filling processes of different runner systems. The simulation results are consistent with the experiment. In addition, the program is capable of providing clearer images for predicting the distribution of the oxide film defects generated during filling a mould.

Dai, X.; Jolly, M.; Yang, X.; Campbell, J.

2012-07-01

387

Modelling of liquid metal flow and oxide film defects in filling of aluminium alloy castings  

International Nuclear Information System (INIS)

The liquid metal flow behaviours in different runner system designs have important effects on the mechanical strength of aluminium alloy castings. In this paper, a new model has been developed which is a two-dimensional program using a finite difference technique and the Marker and Cell (MAC) method to simulate the flow of liquid metal during filling a mould. In the program the Eulerian method has been used for the liquid metal flow, while the Oxide Film Entrainment Tracking Algorithm (OFET) method (a Lagrangian method) has been used to simulate the movement of the oxide film on the liquid metal surface or in the liquid metal flow. Several examples have been simulated and tested and the relevant results were obtained. These results were compared with measured bending strengths. It was found that the completed program was capable of simulating effectively the filling processes of different runner systems. The simulation results are consistent with the experiment. In addition, the program is capable of providing clearer images for predicting the distribution of the oxide film defects generated during filling a mould.

388

Influence of transport mechanisms on nucleation and grain structure formation in DC cast aluminium alloy ingots  

International Nuclear Information System (INIS)

The grain structure formation in direct chill (DC) casting is directly linked to nucleation, which is generally promoted by inoculation. Inoculation prevents defects, but also modifies the physical properties by changing the microstructure. We studied the coupling of the nucleation on inoculant particles and the grain growth in the presence of melt flow induced by thermosolutal convection and of the transport of free-floating equiaxed grains. We used a volume-averaged two-phase multiscale model with a fully coupled description of phenomena on the grain scale (nucleation on grain refiner particles and grain growth) and on the product scale (macroscopic transport). The transport of inoculant particles is also modeled, which accounts for the inhomogeneous distribution of inoculant particles in the melt. The model was applied to an industrial sized (350mm thick) DC cast aluminium alloy ingot. A discretised nuclei size distribution was defined and the impact of different macroscopic phenomena on the grain structure formation was studied: the zone and intensity of nucleation and the resulting grain size distribution. It is shown that nucleation in the presence of macroscopic transport cannot be explained only in terms of cooling rate, but variations of composition, nuclei density and grain density, all affected by transport, must be accounted for.

389

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

International Nuclear Information System (INIS)

The electrochemical behaviour of AlF3 was investigated in LiF-CaF2 medium first with inert tungsten and then with reactive nickel electrodes. Cyclic voltammetry, square-wave voltammetry and chronopotentiometry indicated that the reduction of Al(III) in Al(0) is a single-step process exchanging three electrons: Al(III) + 3e- = Al The electrochemical reduction is controlled by the diffusion of AlF3 in the solution. On a nickel electrode, a depolarisation effect for Al(III) reduction was observed in cyclic voltammetry due to the formation of Al-Ni alloys when aluminium ions react with the nickel substrate. Galvanostatic and potentiostatic electrolyses on a nickel electrode led to the formation of four nickel aluminides characterised by SEM: AlNi3, AlNi, Al3Ni2 and Al3Ni. Layers with a uniform composition of AlNi3, AlNi and Al3Ni2 were prepared by varying the electrolysis potential, the current density and duration of intermetallic diffusion

390

Thermal Analysis on Butt Welded Aluminium Alloy AA7075 Plate Using FEM  

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Full Text Available Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are taken into account through boundary conditions for the outward heat flux. Linear FE transient thermal analysis is performed using surface heat source model with Gaussian distribution to compute highest temperature in AA7075 plates. The objective of this project is to simulate the welding process by using the finite element method. After the model is built and verified, the main objective of this project is to study the effects of varying the welding process parameters on the thermo-mechanical responses. In addition to that, the aim of this research is also to find a relationship between welding parameters and the responses of single pass butt welding are evaluated through the finite element analysis. The study of this paper covers the effects of varying heat input, welding speed on the thermo-mechanical responses of the weldment after cooling down to room temperature.

M. Pal Pandi

2014-03-01

391

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

Directory of Open Access Journals (Sweden)

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

P. Prasanna

2010-06-01

392

Microstructure and high temperature deformation of an ultra-fine grained ECAP AA7075 aluminium alloy  

Energy Technology Data Exchange (ETDEWEB)

An AA 7075 aluminium alloy with an ultra-fine grained structure was prepared through equal channel angular pressing (ECAP) at pressing temperatures T ECAP of 120, 170, and 220 C. A decrease in T{sub ECAP} from 220 to 120 C was found to lead to a more pronounced refinement of the microstructure and to worse stability of the microstructure - the onset of grain coarsening was displaced to lower temperatures. The material pressed with the highest T{sub ECAP} exhibited superplastic behaviour at temperatures close to 400 C and grain boundary sliding was identified as the dominant operating deformation mechanism. The materials prepared with both of the lower T{sub ECAP} exhibited only enhanced ductility of about 200%, however this behaviour was observed at temperatures as low as 200 C. It was found that this 'low temperature superplasticity' resulted from a combined operation of grain boundary sliding at selected grain boundaries and glide of lattice dislocations. (orig.)

Malek, Premysl; Turba, Krystof; Cieslar, Miroslav; Harcuba, Petr [Charles Univ., Prague (Czech Republic). Dept. of Physics of Materials

2013-01-15

393

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

Directory of Open Access Journals (Sweden)

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

Magier M.

2012-08-01

394

Electrochemical etching of AA5083 aluminium alloy in trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ionic liquid  

International Nuclear Information System (INIS)

Highlights: •Ionic liquids were employed in electrochemical pretreatment for AA5083 alloy. •Improved corrosion resistance was observed on the ionic liquid treated AA5083 alloy surface. •The improvement in corrosion was found to be due to an electrochemical etching process similar to acid etching. -- Abstract: Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P6,6,6,14][NTf2]) ionic liquid is shown to react with AA5083 aluminium alloy under a two-step anodic polarisation, leading to partial passivation of the surface. Surface characterisation established that an electrochemical etching process had occurred, comparable to acid etching of aluminium. Energy dispersive X-ray spectroscopy (EDXS) and X-ray photoelectron spectroscopy (XPS) results indicated that magnesium de-alloyed from Mg2Si intermetallic particles and metal fluorides were deposited onto the remaining Mg2Si sites, leading to a decrease in the anodic corrosion kinetics (to one third of that of the control) as well as a 100 mV vs. SCE increase in the corrosion and pitting potentials

395

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

Science.gov (United States)

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

Kruszka, L.; Magier, M.

2012-08-01

396

Metal head - dependent HTC in sand casting simulation of aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In order to obtain reliable sand casting products, it is essential that the temperature distribution within the alloy during cooling is accurately known at each point by FEM simulation. This requires a great precision in setting the Heat Transfer Coefficients (HTC at the boundaries. In particular for castings of big size, chills are frequently at different heights, so that remarkable differences arise from the metal head effect.Design/methodology/approach: An A356 alloy was cast and cooled. The castings were mono-directionally solidified in a experimental equipment modified to accept a controlled variable metal-head. HTC were evaluated in a side arm, where a chill end ensured a dominant unidirectional heat flow during cooling. At the end of a square horizontal channel, an aluminium chill of the same section and 60 mm in depth determined nearly one-dimensional cooling conditions.Findings: The evolution of heat transfer coefficient (HTC in the sand casting of A357 aluminum alloy against aluminum chills is evaluated with different metal heads in order to study the effect of pressure on the HTC. Inverse modeling techniques based on Beck’s analysis were used to determine the experimental evolution of HTC as a function of time, casting temperature and chill temperature. The HTC evolution at the casting-chill boundary is then described as a function of local parameters such as casting-chill interface pressure (as long as they are in contact and interface gap (when solidification shrinkage occurs and the casting detaches from the chill.Practical implications: Finally, the experiments are reconstructed by means of coupled thermal-stress numerical analyses and the predicted cooling curves are fitted to the experimental ones by adjusting model parameters. As a result, the best parameters for describing the HTC evolution are found, thus allowing to extrapolate any possible HTC behavior on chills at different heights for the same casting.Originality/value: Some transient interface pressure can develop between casting and chill, the effect being negligible in HTC evaluation with the aim to precisely predict the cooling evolution inside the casting.

G.S. Cellini

2008-07-01

397

In-vitro characterization of stress corrosion cracking of aluminium-free magnesium alloys for temporary bio-implant applications.  

Science.gov (United States)

The complex interaction between physiological stresses and corrosive human body fluid may cause premature failure of metallic biomaterials due to the phenomenon of stress corrosion cracking. In this study, the susceptibility to stress corrosion cracking of biodegradable and aluminium-free magnesium alloys ZX50, WZ21 and WE43 was investigated by slow strain rate tensile testing in a simulated human body fluid. Slow strain rate tensile testing results indicated that each alloy was susceptible to stress corrosion cracking, and this was confirmed by fractographic features of transgranular and/or intergranular cracking. However, the variation in alloy susceptibility to stress corrosion cracking is explained on the basis of their electrochemical and microstructural characteristics. PMID:25063163

Choudhary, Lokesh; Singh Raman, R K; Hofstetter, Joelle; Uggowitzer, Peter J

2014-09-01

398

Mechanical Behaviour of Friction Stir Welding Joints of Aluminium alloy of AA6351 with AA6351 and AA6351 with AA5083  

Directory of Open Access Journals (Sweden)

Full Text Available Modern structural application demands reduction in both the weight and as well as cost of the fabrication and production of materials. Aluminium alloys are the best choice for the reduction of weight, cost and replacing steels in many applications and Friction Stir Welding (FSW process efficient and cost effective process. FSW is solid state welding process in which material is not melted during welding process so it overcomes many welding defects compared to conventional fusion welding process which is initially used for low melting materials. This process is initially developed for low melting materials like Aluminium, Magnesium, Zinc but now process is useful for high melting materials like steel and also for composites materials. The present study describes the effect of FSW process involving butt joining of similar Aluminium alloy combinations of AA6351 with AA6351 and dissimilar Aluminium ally combinations of AA6351 with AA5083 on the tensile, hardness and impact behaviour.

G.Gopala Krishna

2014-04-01

399

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

Directory of Open Access Journals (Sweden)

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

M. Br?na

2011-01-01

400

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

International Nuclear Information System (INIS)

Nanoindentation has been used to study the hardness changes produced by scratching of aluminium alloy AA2024, with and without a clad layer of pure aluminium. The hardness was mapped around scratches made with diamond tools of different profiles. One tool produced significant plastic damage with associated hardening at the scratch root, whilst the other produced a 'cleaner' cut with no hardening. The different behaviours are attributed to whether the tool makes the scratch by a 'cutting' or a 'ploughing' mechanism. The degree of plastic damage around the scratches has been correlated with peak broadening data obtained using synchrotron X-ray diffraction. There was no change observed in the local hardness around the scratch with fatigue loading.

401

Sodium oleate adsorption and its effect on dissolution of aluminium, iron and their alloys in neutral media  

International Nuclear Information System (INIS)

Sodium oleate adsorption and its effect on the dissolution of aluminium, iron, aluminium-6% magnesium alloy and the Kh18N10T steel are studied in neutral media (buffer borate solutions, containing additions of SO42- or Cl-). In the region of protective concentrations of inhibitor the strictly oriented, densely compressed polylayers of sodium oleate are formed, in which the axes of carboxyl groups and fatty chains are directed in perpendicular to the metal surface. The bond strength of the adsorbed layers with a sublayer is conditioned by their polymerization, which is accompanied by the scission of double bonds in molecules. A relation between the protective ability, orientation and state of polymerization of the adsorbed layers is established. Sodium oleate adsorption on the oxidazed surface of metals does not result in the formation of new compounds, and iron oleate is formed on the reduced surface of iron

402

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

Directory of Open Access Journals (Sweden)

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

Uday M. Basheer

2012-03-01

403

Effect of Friction Stir Welding on Mechanical Properties of Dissimilar Aluminium Aa6061 and Aa2014 Alloy Joints  

Directory of Open Access Journals (Sweden)

Full Text Available In present study, Dissimilar Friction Stir Butt Welds made of 2014 and 6061 Aluminium alloys were performed with various welding parameter. The present study deals with the influence of Square Profile Pin on Friction Stir Welded joint. FSW parameter such as Tool Rotational Speed, Welding Speed and Axial Force plays a significant role in the assessment of mechanical properties. Using ANOVA and Signal to Noise ratio, influence of FSW process parameters is evaluated and optimum welding condition for maximizing mechanical properties of the joint is determined. An Artificial Neural Network (ANN model was developed for the analysis and simulation of the correlation between the Friction Stir Welding (FSW parameters of aluminium (Al plates and mechanical properties and compared the experimental values with the ANN predicted values.

P. Purushotham*

2014-04-01

404

Influence of friction stir welding process and tool parameters on strength properties of AA7075-T6 aluminium alloy joints  

International Nuclear Information System (INIS)

The aircraft aluminium alloys generally present low weldability by traditional fusion welding process. The development of the friction stir welding has provided an alternative improved way of satisfactorily producing aluminium joints, in a faster and reliable manner. In this present work, the influence of process and tool parameters on tensile strength properties of AA7075-T6 joints produced by friction stir welding was analysed. Square butt joints were fabricated by varying process parameters and tool parameters. Strength properties of the joints were evaluated and correlated with the microstructure, microhardness of weld nugget. From this investigation it is found that the joint fabricated at a tool rotational speed of 1400 rpm, welding speed of 60 mm/min, axial force of 8 kN, using the tool with 15 mm shoulder diameter, 5 mm pin diameter, 45 HRc tool hardness yielded higher strength properties compared to other joints.

405

Examination of the effect of Sc on 2000 and 7000 series aluminium alloy castings: for improvements in fusion welding  

International Nuclear Information System (INIS)

It has been reported that small additions of scandium (Sc) can improve the weldability and mechanical properties of some aluminium aerospace alloys that are normally considered to be 'unweldable'. In order to determine the mechanisms by which these improvements occur, and more rapidly arrive at optimum Sc addition levels, small wedge-shaped castings have been used to simulate the cooling rates found in MIG/TIG welds. Using this technique, a range of Sc addition levels have been made to two typical Al-aerospace alloys, 2024 and 7475. It has been found that when the Sc level exceeds a critical concentration, small Al3Sc primary particles form in the melt and act as very efficient grain nucleants, resulting in simulated fusion zone grain sizes as fine as 15 ?m. This exceptional level of grain refinement produced an unusual grain structure that exhibited no dendritic, or cellular, substructure and a large increase in strength and ductility of the castings. Sc also produced changes in the alloy's freezing paths, which cannot yet be fully explained, but led to the appearance of the W phase in the 2024 alloy and, in both alloys, an overall reduction in the amount of eutectic formed during solidification. When coupled with the high level of grain refinement, this behaviour could be used to explain the increased strength and ductility of the castings. In 2000 and 7000 series aluminium alloys, it is therefore, anticipated that optimised Sc bearing filler wires will t optimised Sc bearing filler wires will significantly improve the mechanical properties of the weld metal, as well as reducing the tendency for solidification cracking

406

Development of the coarse intermetallic particle population in wrought aluminium alloys during ingot casting and thermo-mechanical processing  

Energy Technology Data Exchange (ETDEWEB)

The coarse, Fe-containing intermetallic particles which form during ingot casting are well known to play important roles in determining the downstream microstructural development and final gauge properties of rolled aluminium alloy products. To understand, and ultimately to predict and control these various influences, it is necessary to know how the intermetallic population itself develops through the process stream. The phase type, morphology, and size and spatial distribution of the constituent particles in a final gauge sheet or foil product will be the result of the complete sequence of manufacturing steps which have been applied, from ingot casting through to cold rolling. This paper describes work conducted to improve understanding of the development of the coarse particle population through these various processing stages. Drawing upon examples from several different alloy systems and end applications, it illustrates how a greater appreciation of the mechanisms involved is leading to a better capability to predict this important aspect of microstructural evolution in wrought aluminium alloys. (orig.)

Hamerton, R.G.; Cama, H.; Meredith, M.W. [Alcan Labs. Ltd., Banbury (United Kingdom)

2000-07-01

407

The study of intergranular corrosion in aircraft aluminium alloys using X-ray tomography  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} IGC is stochastic, where initiation is statistical and growth kinetics was somewhat predictable. {yields} Dissolved oxygen concentration was more important than the concentration of salt in the droplet. {yields} A limiting depth occurred for AA2024, whereas no limiting depth occurs for AA7050 after 168 h exposure. {yields} A limiting depth may be controlled by the transport of dissolved oxygen down the corrosion fissure. {yields} A limiting IGC depth is dependent on the overpotential of the SDZ (adjacent to the grain boundary). - Abstract: Atmospheric corrosion is one of the leading causes of structural damage to aircraft. Of particular importance is pitting and intergranular corrosion, which can develop into fatigue cracks, stress corrosion cracks, or exfoliation. Therefore it is of interest to the Australian Defence Force (ADF) to understand how corrosion ensues in susceptible aircraft aluminium alloys, such as AA2024-T351 and 7050-T7451. However, there are many difficulties in measuring the extent of intergranular corrosion, since it is predominantly hidden below the surface. Traditionally, cross-sectioning has been used to view and measure the depth of attack. In the present work, 2 mm diameter pin specimens were contaminated with a droplet of 3.5% NaCl and exposed to constant humidity that resulted in intergranular corrosion. X-ray computed tomography was then used to non-destructively assess the depth and volume of corrosion both as a function of time in 97% relative humidity, and as a function of relative humidity after 168 h exposure. Both corrosion depth and volume increased with time, but there was evidence for a limiting depth in AA2024. Depth and volume also increased with relative humidity of the environment, for which the time-of-wetness and oxygen concentration of the droplets were considered the important factors in driving the corrosion process.

Knight, S.P., E-mail: steven.knight@rmit.edu.a [School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne (Australia); Defence Materials and Technology Centre, Melbourne (Australia); Salagaras, M. [Defence Science and Technology Organisation, Melbourne (Australia); Trueman, A.R. [Defence Science and Technology Organisation, Melbourne (Australia); Defence Materials and Technology Centre, Melbourne (Australia)

2011-02-15

408

Influence of Hot Deformation on Mechanical Properties and Microstructure of a Twin-Roll Cast Aluminium Alloy EN AW-6082  

Science.gov (United States)

Thin strips of medium- and high-strength age-hardening aluminium alloys are widely used in the automotive industry. Reducing their production costs caused by high energy consumption is an actual challenge. The implementation of the twin-roll casting technology is promising. However, mechanical properties of directly cast high-alloyed thin aluminium strips are oftentimes inadequate to standard specifications. In this work, the influence of a hot deformation following a twin-roll cast strip process on the mechanical properties and microstructure is investigated. For this study strips of age-hardening aluminium alloy EN AW-6082—manufactured at a laboratory scaled twin-roll caster—were single-pass rolled at temperatures of 420 °C and true strains of up to 0.5. The mechanical properties of the as-cast and by different strains hot deformed material in the soft-annealed and age-hardened states were characterized by tensile tests. The results reveal that the twin-roll cast material features the necessary strength properties, though it does not meet the standard requirements for ductility. Furthermore, the required minimum strain during hot rolling that is necessary to ascertain the standard specifications has been determined. Based on micrographs, the uniformity of the mechanical properties and of the microstructure as a result of recrystallization due to hot metal forming and heat treatment were determined. A fine-grain microstructure and satisfactory material ductility after prior rolling with a true strain above 0.41 for the age-hardened state T6 and above 0.1 for the soft-annealed state O have been established.

Grydin, O.; Stolbchenko, M.; Nürnberger, F.; Schaper, M.

2014-03-01

409

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

Directory of Open Access Journals (Sweden)

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

Estelle Parra-Denis

2011-05-01

410

Electromagnetic Gauge Study of Laser-Induced Shock Waves in Aluminium Alloys  

Science.gov (United States)

The laser-shock behaviour of three industrial aluminum alloys has been analyzed with an Electromagnetic Gauge Method (EMV) for measuring the velocity of the back free surface of thin foils submitted to plane laser irradiation. Surface pressure, shock decay in depth and Hugoniot Elastic Limits (HEL) of the materials were investigated with increasing thicknesses of foils to be shocked. First, surface peak pressures values as a function of laser power density gave a good agreement with conventional piezoelectric quartz measurements. Therefore, comparison of experimental results with computer simulations, using a 1D hydrodynamic Lagrangian finite difference code, were also in good accordance. Lastly, HEL values were compared with static and dynamic compressive tests in order to estimate the effects of a very large range of strain rates (10^{-3} s^{-1} to 10^6 s^{-1}) on the mechanical properties of the alloys. Cet article fait la synthèse d'une étude récente sur la caractérisation du comportement sous choc-laser de trois alliages d'aluminium largement utilisés dans l'industrie à travers la méthode dite de la jauge électromagnétique. Cette méthode permet de mesurer les vitesses matérielles induites en face arrière de plaques d'épaisseurs variables par un impact laser. La mise en vitesse de plaques nous a permis, premièrement, de vérifier la validité des pressions d'impact superficielles obtenues en les comparant avec des résultats antérieurs obtenus par des mesures sur capteurs quartz. Sur des plaques d'épaisseurs croissantes, nous avons caractérisé l'atténuation des ondes de choc en profondeur dans les alliages étudiés et mesuré les limites d'élasticité sous choc (pressions d'Hugoniot) des alliages. Les résultats ont été comparés avec succès à des simulations numériques grâce à un code de calcul monodimensionnel Lagrangien. Enfin, les valeurs des pressions d'Hugoniot mesurées ont permis de tracer l'évolution des contraintes d'écoulement plastique en fonction de la vitesse de déformation pour des valeurs comprises entre 10^{-3} s^{-1} et 10^6 s^{-1}.

Peyre, P.; Fabbro, R.

1995-12-01

411

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

International Nuclear Information System (INIS)

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

412

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

Directory of Open Access Journals (Sweden)

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

D. Hanumantha Rao

2010-09-01

413

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

Scientific Electronic Library Online (English)

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

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

2010-09-01

414

Aluminium alloy containing iron and nickel. Influence of structure and composition on the corrosion behaviour in high temperature water  

International Nuclear Information System (INIS)

The corrosion structures are determined on a series of aluminium (A9) base alloys which contain a total Fe + Ni not superior to 3%. The tests are carried out to 5,000 hours in 350 deg. C deionized water in autoclave. The principal results were as follows: - For iron and nickel contents superior to 0,5%, the first factor is the distribution structure of insoluble intermetallic compounds: the particles must be as fine and randomly dispersed as possible. - The corrosion products developed on the surface may be subdivided in three distinct layers which total thickness tends rapidly towards a limit and stabilises itself. (author)

415

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-15

416

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

International Nuclear Information System (INIS)

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

417

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-10-15

418

Microstructure control and extrudability of aluminium-Mg-Si alloys microalloyed with manganese. [AlMgSi:Mn  

Energy Technology Data Exchange (ETDEWEB)

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 alloys during hot working at low and intermediate strains was described by a new model for the accumulation and annihilation by climb of geometrically necessary dislocations at non-deformable precipitates. Strain hardening behaviour at high strains correlated with the reduction in spacing between grain boundary precipitates. (orig.).

Zajac, S. (Swedish Inst. for Metal Research, Stockholm (Sweden)); Hutchinson, B. (Swedish Inst. for Metal Research, Stockholm (Sweden)); Johansson, A. (Swedish Inst. for Metal Research, Stockholm (Sweden) Graenges Technology Centre, Finspaang (Sweden)); Gullman, L.O. (Swedish Inst. for Metal Research, Stockholm (Sweden) Graenges Technology Centre, Finspaang (Sweden)); Lagneborg, R. (Swedish Inst. for Metal Research, Stockholm (Sweden))

1993-11-01

419

Study of twin-roll cast Aluminium alloys subjected to severe plastic deformation by equal channel angular pressing  

Science.gov (United States)

Aluminium alloys prepared by twin-roll casting method become widely used in industry applications. Their high solid solution supersaturation and finer grains ensure better mechanical properties when compared with the direct-chill cast ones. One of the possibilities how to enhance their thermal stability is the addition of zirconium. After heat treatment Al3Zr precipitates form and these pin moving grain boundaries when the material is exposed to higher temperatures. In the present work twin-roll cast aluminium alloys based on AA3003 with and without Zr addition were annealed for 8 hours at 450 °C to enable precipitation of Al3Zr phase. Afterwards they were subjected to severe plastic deformation by equal channel angular pressing, which led to the reduction of average grain size under 1 ?m. During subsequent isochronal annealing recovery and recrystallization took place. These processes were monitored by microhardness measurements, light optical microscopy and in-situ transmission electron microscopy. The addition of Zr stabilizes the grain size and increases the recrystallization temperature by 100 °C.

Poková, M.; Cieslar, M.

2014-08-01

420

Determination of the alloyed amount of cerium and microdistribution of cerium in steel, cast iron and aluminium by radioassay and autoradiography  

International Nuclear Information System (INIS)

An experimental method for the determination of the amount of rare earth alloyed in steel, cast iron, aluminium and its alloy and a coating-autoradiography technique have been developed. Microautoradiographs show that the cerium is distributed in the grains, but cerium mainly segregates along the grain boundaries and dendrite boundaries of aluminium, Al-Mg alloys and heat-resisting Fe-Cr-Al alloys. Cerium contained in the pearlite is more than that in the ferrite of 16Mn and 25MnTiB steels. There is little cerium in the ferrite and pearlite which surround the spheroidal graphite, while in the pearlite and ledeburite which are located far from the spheroidal graphite there is much cerium. Cerium is distributed uniformly in flake graphite, while it is distributed in various ways in spheroidal graphite. (orig.)

421

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

422

Influence of silicon, aluminium, phosphorus and copper on the phase transformations of low alloyed TRIP-steels  

Energy Technology Data Exchange (ETDEWEB)

Although silicon is very important to prevent carbide precipitation during annealing of low-alloyed TRIP-steels and thus allows the austenite to be stabilized by carbon, it causes problems during processing. Therefore, other alloying elements having a similar effect as silicon have to be considered. Possible candidates to substitute or reduce silicon are aluminium, copper and/or phosphorus, which are supposed to be capable of suppressing carbide formation, too. The influence of reduced silicon contents in combination with alloying elements being capable of substituting silicon completely or partially on the phase transformations occurring during heat treatment is studied. The results of the investigations are compared with a conventional low alloyed TRIP-steel. The phase transformations are investigated by dilatometric measurements on cold rolled material. The influence of the cooling rate after the intercritical annealing on the transformation behaviour of the austenite upon cooling and isothermal holding in the bainitic range is studied. The interpretation of the phase transformations are supported by investigations of the microstructure via light microscopy and measuring the content of retained austenite using a magnetic volumetric method. (orig.)

Traint, S.; Werner, E. [Christian-Doppler Lab. fuer Moderne Mehrphasenstaehle, Lehrstuhl fuer Mechanik mit Materialpruefamt, TU Muenchen (Germany); Pichler, A. [Voestalpine Stahl GmbH (Germany). Research, Development and Testing; Hauzenberger, K. [Voest-Alpine Mechatronics GmbH, Linz (Austria)

2002-07-01

423

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

International Nuclear Information System (INIS)

This paper reveals the effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded AA7075 aluminium alloy. This alloy has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminium alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW) and (iv) pulsed current GMAW (PCGMAW) processes. As welded joint strength is much lower than the base metal strength and hence, a simple aging treatment has been given to improve the tensile strength of the joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. In contrast, conventin GTA and GMA welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Post weld aging treatment is accompanied by an increase in tensile strength and tensile ductility

424

Intermetallic phase particles in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In the technical Al alloys even small quantity of impurities - Fe and Mn - causes the formation of new phase components. Intermetallic particles form either on solidification or whilst the alloy is at a relatively high temperature in the solid state, e.g. during homogenization, solution treatment or recrystallization. The exact composition of the alloy and casting condition will directly influence the selection and volume fraction of intermetallic phases. The main objective of this study was to analyze the morphology and composition of complex microstructure of intermetallic phases in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys.Design/methodology/approach: In this study, several methods were used such as: optical light microscopy (LM, scanning (SEM electron microscopy in combination with X-ray analysis (EDS using polished sample, and X-ray diffraction (XRD to identify intermetallics in cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys.Findings: The results show that the microstructure of cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminum alloys in T6 condition consisted a wide range of intermetallic phases. By using various instruments (LM, SEM, XRD and techniques (imagine, EDS following intermetallic phases were identified: ?-Al5FeSi, ?-Al15(FeMn3Si - in AlSi5Cu1Mg alloy and Al7Cu4Ni, Al12Cu23Ni, Al2CuMg, AlCuFeNi - in AlCu4Ni2Mg2 alloy.Research limitations/implications: In order to complete and confirm obtained results it is recommended to perform further analysis of the investigated aluminium alloys. Therefore it is planned to include in a next studies, microstructure analysis of the alloys by using transmission electron microscopy technique (TEM.Practical implications: Since the morphology, crystallography and chemical composition affect the intermetallic properties, what involves changes of alloy properties, from a practical point of view it is important to understand their formation conditions in order to control final constituents of the alloy microstructure.Originality/value: This paper proposes the best experimental techniques for analysis of the intermetallic phases occurring in the cast AlSi5Cu1Mg and AlCu4Ni2Mg2 aluminium alloys. This study has showed that the chemical phenol extraction method for the cast a