Search results for "aluminium alloy"
showing 10 items of 57 documents
Tool Failure in Sequential Cutting of two Different Materials
1985
In this paper the authors show that the premature tool breakage, characteristic of interrupted cutting, can be enhanced in sequential cutting of two materials having different mechanical and chemical properties. The results of experimental investigations carried out in turning pieces consisting of medium carbon steel and aluminium alloy show that the time to failure is significatively lower than that occurring in machining only one of the two materials; moreover the morphology of the damage depends by the cutting order. Working with the sequence steel-Al alloy welding phenomena caused by strong deoxidation due to the latter material are observed; these phenomena cause the early development …
Friction stir welding of dissimilar aluminium– magnesium joints: Sheet mutual position effects
2015
Friction stir welding (FSW) is a solid state welding process used to weld difficult to be welded or unweldable materials as aluminium alloys. In the last years, other materials have been successfully tested as magnesium, titanium and nickel based alloys. Dissimilar joints can be obtained by FSW, but issues arise concerning the correct choice of the process parameters. In the paper, the results of an experimental and numerical campaign aimed to produce dissimilar AZ31-AA6016-T6 butt joints are presented. The effect of sheet mutual position and main process parameters was investigated. It was found that intermetallics are the main cause of the poor quality of the joints. Sound joints can be p…
Influence of the microstructure and laser shock processing (LSP) on the corrosion behaviour of the AA2050-T8 aluminium alloy
2011
International audience; The corrosion behaviour of AA2050-T8 was studied after polishing and after laser shock processing (LSP) treatment using the electrochemical microcell technique and the SVET. After polishing, pitting at constituent particles and intergranular corrosion were observed. By contrast, no intergranular corrosion developed after LSP. Microcell measurements revealed that LSP increases the pitting potential. SVET measurements revealed that local anodic currents are systematically lower on LSP-treated surfaces than on polished ones. The current density on the LSP-treated surface remains constant around 50 μA cm−2 up to 123 min after immersion, while on the polished surface it r…
Local electrochemical impedance spectroscopy study of the influence of ageing in air and laser shock processing on the micro-electrochemical behaviou…
2011
International audience; In the present paper, the micro-electrochemical behaviour of AA2050-T8 in 0.1 M NaCl was first studied after polishing by means of local electrochemical impedance spectroscopy and field-emission scanning electron microscopy/electron dispersive spectroscopy (FE-SEM/EDS). The influence of ageing in air and LSP was then investigated. Ageing in air for three months led to an increase in the charge transfer resistance. This was clearly observed in sites surrounding constituent particles where the charge transfer resistance was in the order of 1 MΩ cm2 (instead of 10-3 MΩ cm2 after polishing). Increased passivity around particles was confirmed from FE-SEM/EDS analysis. On …
Improving friction stir welding of blanks of different thicknesses
2007
Friction stir welding (FSW) appears to be a promising process even in the welding of blanks of different thicknesses. Actually, such particular tailor welded blanks (TWBs) are usually characterized by a reduction in ductility due to the utilized fusion welding process. In this paper the authors, starting from a preliminary feasibility study, investigate the possibility to improve the mechanical performances of friction stir welded blanks of aluminum alloy with different thicknesses. Both experiments and a FE analyses are developed for a few case studies with different thickness ratios between the blanks. The numerical investigations are performed with the aim to highlight the material tempe…
Electrochemical behavior of nanocrystalline iron aluminide obtained by mechanically activated field activated pressure assisted synthesis
2004
Abstract The corrosion behavior of nanocrystalline iron aluminide obtained by mechanically activated field—activated pressure—assisted synthesis was investigated in sulphuric acid media using potentiodynamic curves. The effect of microstructure on the electrochemical corrosion resistance was investigated by examining samples which were heat treated to effect a change in crystallite size and microdistorsion.
Validation of frictional studies by double-cup extrusion tests in cold-forming
1996
Abstract Studies on frictional conditions in cold-forming have shown that, for a given lubricant, friction factor values are strongly affected by the test method. In the present paper, different cold-forging processes of an aluminium alloy, are modelled by a FEM numerical code using the m values obtained by both the double cup extrusion and ring compression tests. It appears that the m values given by the ring tests can be effectively used in the simulation of upsetting processes, while the m values derived by the double cup extrusion tests are more appropriate for predictions in extrusion and closed-die forging operations.
CDRX modelling in friction stir welding of aluminium alloys
2005
In the paper a numerical model aimed to the determination of the average grain size due to continuous dynamic recrystallization phenomena (CDRX) in friction stir welding processes of AA6082 T6 aluminum alloys is presented. In particular, the utilized model takes into account the local effects of strain, strain rate and temperature; an inverse identification approach, based on a linear regression procedure, is utilized in order to develop the proper material characterization.
Fatigue Crack Growth in Titanium and Aluminium Alloys under Bending
2007
The paper contains results of investigations of the crack growth in plane specimens made of Ti-6Al-4V titanium alloy and AlCu4Mg1 aluminium alloy under cyclic bending. The tests were done on specimens with the stress concentrators being one-sided sharp notch. On the fractures there have been observed first of all transcrystalline cracks through the α phase grains for both materials.
FSW of AA2139-T8 Butt joints for aeronautical applications
2011
The effect of process parameters on mechanical and microstructural properties of AA 2139 T8 joints produced by friction stir welding (FSW) was analysed by means of statistical tools. Three different parameters were taken into account: angular speed ( ω), welding speed ( va), and plunging depth ( p); each of them was varied on three levels. Forces and temperatures achieved during the welding were monitored and analysed for all joints. An accurate microstructural analysis was performed: the occurrence of some remarkable defects, typical of FSW, such as tunnel or lack of penetration, was related to actual process parameters adopted. The extension of each FSW characteristic zone was measured a…