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Showing papers on "Aluminium alloy published in 2007"


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

385 citations


Journal ArticleDOI
TL;DR: In this paper, microstructural properties of hot isostatically pressed Ti-6Al-4V alloy with 0, 0.05, 0., 10, and 0.40 wt.% B additions have been examined, with particular emphasis on identifying the micro-structural length scale (grain size vs. lath size) that controls the mechanical properties of these alloys.

357 citations


Journal ArticleDOI
TL;DR: In this article, the effect of different shoulder geometries on the mechanical and microstructural properties of a friction stir welded joints have been studied in the process was used on 6082 T6 aluminium alloy in the thickness of 1.5mm.

302 citations


Journal ArticleDOI
TL;DR: In this paper, the inhibiting effect of several organic compounds on the corrosion of 2024 aluminium alloy in neutral chloride solution was investigated in the context of electrochemical impedance spectroscopy (EIS).

288 citations


Journal ArticleDOI
TL;DR: In this article, the aluminum and aluminum alloys with aqueous alkaline solutions were used for hydrogen production. And the results showed that an increase in base concentration and working solution temperature produced an increase of hydrogen production rate using pure aluminum.

257 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of sliding distance, Al 2 O 3 particle content and size, SiC abrasive grit size and wear load on the wear properties of the composites were systematically investigated.

242 citations


Journal ArticleDOI
TL;DR: In this article, a series of Al-based materials were prepared by ball milling and/or melting, and the results showed that mechanical milling was more favorable than the melting method to synthesize the Al alloys containing some metals with lower melting point and easier vaporization in the melting process.

225 citations


Journal ArticleDOI
TL;DR: In this article, the effect of the FSW process on the microstructure and, consequently, on the tensile and low-cycle fatigue behaviour, of an aluminium matrix (AA7005) composite reinforced with 10.5% of Al2O3 particles (W7A10A).

222 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of tool geometry on microstructure and static strength in friction stir spot welds of 6061 aluminium alloy sheets was studied, where tools with three different probe lengths were used to join the aluminium sheet with different tool rotational speeds and tool holding times.
Abstract: The effect of tool geometry on microstructure and static strength in friction stir spot welds of 6061 aluminium alloy sheets was studied. Tools with three different probe lengths were used to join the aluminium sheet with different tool rotational speeds and tool holding times. The weld microstructures varied significantly depending on probe length, tool rotational speed and tool holding time. Two particular aspects were identified: the thickness of the upper sheet under the shoulder indentation and the nugget size. The former decreased with increasing probe length at the shortest tool holding time and the slowest tool rotational speed, but there were no discernible differences in other welding conditions, while the latter increased with increasing probe length, tool rotational speed and tool holding time. The tensile shear strength increased with increasing probe length, while the cross-tension strength was not affected significantly by probe length. Two fracture modes were observed: shear fracture of the nugget and mixed mode fracture under tensile shear loading, and nugget debonding and pull-out under cross-tension loading. Based on experimental observation of the microstructures, the effect of probe length on static strength and the fracture mechanisms were discussed.

176 citations


Journal ArticleDOI
TL;DR: In this paper, an interpenetrating graphite/aluminium composites were produced by gas pressure infiltration of aluminium alloys with varying silicon content into porous graphite preforms.
Abstract: We have produced interpenetrating graphite/aluminium composites by gas pressure infiltration of aluminium alloys with varying silicon content into porous graphite preforms. Infiltration experiments at 750 °C have shown that a silicon content of up to 18 wt.% can reduce the formation of aluminium carbide but cannot completely deter it. Optical and scanning electron microscopy revealed numerous lath-like interfacial aluminium carbide crystals in the μm regime which, however, did not affect the flexural strength of our composites. Severe aluminium carbide degradation was observed within a few days on composites exposed to ambient conditions. Carbide-free composites were produced by reducing the infiltration temperature to 670 °C for the eutectic alloy.

166 citations


Journal ArticleDOI
TL;DR: In this article, a pyramidal lattice truss structure with robust nodes and close to 100% utilization of the sheet material was constructed using a brazing technique and tested in thickness compression, and in both transverse and longitudinal shear.

Journal ArticleDOI
TL;DR: In this article, a multistage fatigue model for high cycle fatigue of a cast aluminum alloy was modified to consider the structure-property relations for cyclic damage and fatigue life of a high strength aluminum alloy 7075-T651 for aircraft structural applications.

Journal ArticleDOI
Hüseyin Uzun1
TL;DR: In this article, the feasibility of friction stir welding (FSW) for joining of AA2124/SiC/25p composite materials has been demonstrated and the weld nugget exhibits the relatively homogeneous SiC particle distributions but has fine particle density bands.

Journal ArticleDOI
TL;DR: In this article, the laser joining of a low carbon steel to a 6000 series aluminium alloy was realized in keyhole welding mode in a steel-on-aluminium overlap configuration and was investigated in a three-fold approach: (1) process optimisation, (2) material characterisation and (3) mechanical testing.
Abstract: The laser joining of a low carbon steel to a 6000 series aluminium alloy was realised in key-hole welding mode in a steel-on-aluminium overlap configuration and was investigated in a three-fold approach: (1) process optimisation, (2) material characterisation and (3) mechanical testing. No-defect welds, composed of a solid solution of aluminium in iron and richer aluminium “white solute bands” of FeAl phases were obtained when limiting steel penetration in aluminium to below 500 μm. Embrittlement of the joining zone was observed, mainly located on the weld–aluminium interfaces composed of Fe2Al5 and/or FeAl3 phases with thicknesses between 5 μm and 20 μm. Limiting penetration to below 500 μm allowed to restrict steel to aluminium dilution in order to confine the hardness of the welds. With such penetration depths, up to 250 N/mm in linear strength could be achieved, with failures located in the weld–aluminium interfaces. Increasing penetration depth led to a change in the assembly weak points (in the weld and on the steel–weld interfaces) and induced a severe decrease in strength.

Journal ArticleDOI
TL;DR: In this article, the magnetic pressure seam welding method was used for lap joining of low carbon steel (SPCC)/A6111 aluminum alloy, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM.
Abstract: Lap joining of low carbon steel (SPCC)/A6111 aluminum alloy was carried out using the magnetic pressure seam welding method. Interfacial microstructure, in particular, an intermediate layer formed at the weld interface was precisely examined using TEM. Tensile tests were also performed for the lap joints. Lap joining was successfully attained in several microseconds with no temperature increase. Weld interface of the lap joint showed wavy morphology and the intermediate layer was observed along the wavy interface. These microstructures are similar to that of the explosive weld lap joint. TEM observation revealed that the intermediate layers consist of fine aluminum grains (around 100 nm) and more finely dispersed intermetallic particles. A6111 matrix close to the weld interface also exhibited extremely refined grain structure. The bonding strength of the joint was quite high and it failed at the parent plate. The multi-phase intermediate layer and grain-refined aluminum layer are considered to be the origin of high interfacial bonding strength of the lap joint.

Journal ArticleDOI
TL;DR: In this article, a generalized three-dimensional dislocation-density-based two-phase composite model was further developed to incorporate the effects of hydrostatic pressure during severe plastic deformation.

Journal ArticleDOI
TL;DR: Rolled 3xxx series Al alloys, e.g., EN AW-3003, are generally used as fin or tube material in heat exchangers for automobiles.

Journal ArticleDOI
TL;DR: In this article, a new method to produce high purity hydrogen using reactions of aluminum and sodium borohydride with aqueous alkaline solutions is described, which mainly consumes water and aluminum (or its alloys) which are cheaper raw materials than the borhydride.

Journal ArticleDOI
TL;DR: In this article, the electrochemical behavior of three titanium alloys, namely Ti-13Nb-13Zr, Ti-6A1-4V and Ti- 6A 1-7Nb, for implant materials was evaluated in Hanks' solution by electrochemical techniques.
Abstract: In this investigation the electrochemical behaviour of the Ti-13Nb-13Zr, Ti-6A1-4V and Ti-6A1-7Nb alloys, for application as implant materials was evaluated in Hanks' solution by electrochemical techniques. The alloys were immersed in this solution for 410 days and periodically they were tested by electrochemical impedance spectroscopy. At the end of this period, polarization curves of the three titanium alloys were obtained. The electrochemical impedance experimental results were interpreted using an equivalent electrical circuit that simulates a duplex structure oxide composed of an inner compact layer, here called barrier layer, and an outer and porous layer. The results indicated that all the alloys present a very high corrosion resistance in the electrolyte used, typical of passive alloys, and that the corrosion resistance is mainly due to the barrier layer. The passive like behaviour was maintained during the whole period of test.

Journal ArticleDOI
TL;DR: In this paper, the effects of silicon carbide (SiC) particles on the as-cast microstructure and properties of Al-Si-Fe alloy composites produced by double stir-casting method have been studied.
Abstract: The effects of silicon carbide (SiC) particles on the as-cast microstructure and properties of Al–Si–Fe alloy composites produced by double stir-casting method have been studied. A total of 5–25 wt% silicon carbide particles were added. The microstructure of the alloy particulate composites produced was examined, the physical and mechanical properties measured include: densities, porosity, ultimate tensile strength, yield strength, hardness values and impact energy. The results revealed that, addition of silicon carbide reinforcement, increased the hardness values and apparent porosity by 75 and 39%, respectively, and decreased the density and impact energy by 1.08 and 15%, respectively, as the weight percent of silicon carbide increases in the alloy. The yield strength and ultimate tensile strength increased by 26.25 and 25% up to a maximum of 20% silicon carbide addition, respectively. These increases in strength and hardness values are attributed to the distribution of hard and brittle ceramic phases in the ductile metal matrix. The microstructure obtained reveals a dark ceramic and white metal phases, which resulted into increase in the dislocation density at the particles–matrix interfaces. These results show that better properties is achievable by addition of silicon carbide to Al–Si–Fe alloy.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the behavior of aluminium alloy-glass fiber-reinforced polypropylene-based fiber-metal laminates (FMLs) subjected to localised explosive blast loading.

Journal ArticleDOI
TL;DR: In this article, an autogenous electron beam (EB) welding of some aluminium alloys leads to a significant strength reduction (undermatching) in the fusion zone due to the loss of strengthening phases.
Abstract: The electron beam (EB) welding process is used to weld any metal that can be arc welded with equal or superior weld quality. EB welding is carried out in a high-purity vacuum environment, which results in freedom from impurities such as oxides and nitrides. Thus, pore-free joints can readily be achieved in metallic materials, such as Al-alloys and Ti-alloys. However, autogenous EB welding of some aluminium alloys leads to a significant strength reduction (undermatching) in the fusion zone due to the loss of strengthening phases. For such Al-alloys, the local microstructure-property relationships should be established to satisfy the service requirement of a welded component with strength undermatching. Autogenous EB welding was performed on 5 mm thick aluminium alloy 7020 plate. Microstructural characterization of the weld metals was made by optical and scanning electron microscopy. Extensive microhardness measurements were conducted in the weld regions of the joints which exhibited a hardness loss in the fusion zone due to the loss of strengthening phases. Tensile properties of the joints were determined by testing flat transverse tensile specimens at room temperature without machining the weld profiles. Furthermore, elastic-plastic fracture toughness tests (CTOD) were carried out on the base material and welded joints at room temperature.

Journal ArticleDOI
TL;DR: In this paper, the effect of hard anodic oxide and plasma electrolytic oxide coatings on the fatigue strength of 7475-T6 aluminium alloy has been investigated, and the results showed that the reduction in fatigue strength was associated with the development of the tensile residual internal stress within the substrate.
Abstract: The effect of hard anodic oxide and plasma electrolytic oxide coatings on the fatigue strength of 7475-T6 aluminium alloy has been investigated. The coated aluminium alloy was tested using constant load uniaxial tensile fatigue machine. Hard anodising led to an appreciable reduction in the fatigue strength of 7475-T6 alloy of about 75% for a 60 μm thick coating. Further, plasma electrolytic oxidation resulted in reduction of the fatigue strength of about 58% for a 65 μm thick oxide coating. The decrease in fatigue strength of the hard anodic oxide coatings was associated with the stress concentration at the microcracks in the coating. The better fatigue performance of the PEO coatings was attributed to the development of the compressive residual internal stress within the coatings. The reduction in the fatigue strength of the PEO coatings as compared to the uncoated material was associated with the development of the tensile residual internal stress within the substrate. This may cause an early crack initiation in the substrate adjacent to the coating.

Journal ArticleDOI
TL;DR: In this article, the results obtained from microstructural (optical and scanning electron microscopy) and mechanical evaluation (hardness, tensile and low-cycle fatigue tests) of an aluminium alloy (AA6061) matrix composite reinforced with 20% fraction of Al 2 O 3 particles (W6A20A), welded using the friction stir welding process.
Abstract: Metal matrix composites reinforced with Al 2 O 3 particles combine the matrix properties with those of the ceramic reinforcement, leading to higher stiffness and superior thermal stability with respect to the corresponding unreinforced alloys. However, their wide application as structural materials needs proper development of a suitable joining processes. The present work describes the results obtained from microstructural (optical and scanning electron microscopy) and mechanical evaluation (hardness, tensile and low-cycle fatigue tests) of an aluminium alloy (AA6061) matrix composite reinforced with 20 vol.% fraction of Al 2 O 3 particles (W6A20A), welded using the friction stir welding process. The mechanical response of the FSW composite was compared with that of the base material and the results were discussed in the light of microstructural modifications induced by the FSW process on the aluminium alloy matrix and on the ceramic reinforcement. The FSW reduced the size of both particles reinforcement and aluminium grains and also led to overaging of the matrix alloys due to the frictional heating during welding. The FSW specimens, tested without any post-weld heat treatment or surface modification showed lower tensile strength and higher elongation to failure respect to the base material. The low-cycle fatigue life of the FSW composite was always lower than that of the base material, mainly at the lower strain-amplitude value. The cyclic stress response curves of the FSW composite showed evidence of progressive hardening to failure, at all cyclic strain-amplitudes, while the base material showed a progressive softening.

Journal ArticleDOI
TL;DR: In this article, an attempt has been made to link friction stir welding (FSW) process control and response variables such as torque, nugget grain size, x axis force and tool rotation rate.
Abstract: In the present paper, an attempt has been made to link friction stir welding (FSW) process control and response variables. Substantial similarities among the relationships between torque, nugget grain size, x axis force and tool rotation rate have been elucidated for three different aluminium alloys. Comparison of the experimental work to results from process simulation indicates that in each case a temperature limit is reached above some critical value of tool rotation rate. A simple method of estimating the strain and strain rate in friction stir welds is presented. The flow stress during FSW is calculated from measured torque values and analysed with respect to aluminium alloy flow stresses measured in standard, high temperature torsion and tensile tests. Results indicate that perhaps either sticking friction conditions are not always applicable during FSW (on all or part of the tool) or that, above a critical tool rotation rate, intermittently lubricated contact is present due to local melting...

Journal ArticleDOI
TL;DR: In this paper, the influence of copper on the morphologies of porous anodic alumina has been investigated under current and voltage control using a sputtering-deposited Al-2.7.% Cu alloy and a commercial AA 2024-T3 aluminium alloy anodized in either sulphuric acid electrolyte or the same electrolyte but with addition of tartaric acid.

Journal ArticleDOI
TL;DR: In this paper, three types of alloys were identified and characterized by Mg 32 (Al, Zn) 49, also known as the τ phase, MgZn phase, and a ternary icosahedral quasi-crystalline phase denoted as the Q phase, respectively.
Abstract: Magnesium is receiving great attention for transport applications, particularly its cast alloys. This investigation focuses on the as-cast microstructure and mechanical properties of permanent-mould cast Mg–Zn–Al alloys with typical compositions within the high zinc castable domain. Three types of alloys were identified and characterized by Mg 32 (Al, Zn) 49 , also known as the τ phase; MgZn phase, also known as the ɛ phase; and a ternary icosahedral quasi-crystalline phase, denoted as the Q phase, respectively. A schematic phase diagram is proposed to show the change of microstructral constituents with element content and the Zn/Al ratio. The diagram reveals that the microstructral constituent is dominated by both the content of Zn or Al and the Zn/Al mass ratio; alloys with a high Zn/Al ratio and a low Al content fall into the ɛ-type; alloys with an intermediate Zn/Al ratio and an intermediate Al content favour the τ-type; and those with a low Zn/Al ratio and a high Al are dominated by the icosahedral quasi-crystalline phase. No Mg 17 Al 12 (γ) phase was found in those ZA series alloys. The solidification process and its effects on the phase constituents were discussed. Preliminary mechanical property testing showed that all the experimental alloys possess comparable ultimate strength and yield strength with the AZ91 alloy at ambient temperature, but show far superior creep resistance at elevated temperatures. Moreover, while ambient-temperature properties solely depend on the total element contents, the τ- and the Q-type alloys show greater potential than the ɛ-type alloys on the improvement of elevated temperature properties.

Journal ArticleDOI
TL;DR: In this article, the effect of the presence of soft zones along grain boundaries in high-strength Al and β-Ti alloys is discussed, and the role of the strength difference between the age hardened matrix and the soft grain boundary layers is discussed.
Abstract: This paper discusses the effect of the presence of soft zones along grain boundaries in high-strength Al and β-Ti alloys. Soft zones are deformed preferentially and therefore have a strong effect on fracture related properties. The presentation focuses on the ductility, the high-cycle fatigue strength, and the fracture toughness. For microstructures with pancake-shaped grains, the anisotropy of the mechanical properties is discussed on the basis of the effective slip length, determined by the length of the soft grain boundary zones. In high-strength Al alloys, the presence of hard inclusions additionally affects the fracture behavior. For β-Ti alloys, the role of the strength difference between the age hardened matrix and the soft grain boundary layers is discussed.

Journal ArticleDOI
TL;DR: In this paper, the electrochemical behavior of an Al-4.5% Cu alloy solidified under unsteady-state heat flow conditions was evaluated through the analysis of both potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) tests in a 0.5m NaCl solution at 25°C.

Journal ArticleDOI
TL;DR: In this paper, the effect of various training algorithms on learning performance of the neural networks on the prediction of bending strength and hardness behaviour of particulate reinforced Al-Si-Mg metal matrix composites (MMCs) was investigated.