Room temperature deformation behaviour of A1Mg6.5 alloy sheet

Abstract

Room temperature tensile test have been performed with initial strain rates of 6.7 x 10(-4) s(-1), 6.7 x 10(-3) s-(1) and 6.7 x 10(-2) s(-1), on AlMg6.5 alloy sheet, after imposing 5% to 70% cold rolling reductions, and annealing at 320 degrees C/3 h. The applied working conditions were found to affect the yield point elongation, dynamic strain aging and the related steady state strain rate sensitivity. The Portevin-LeChatelier effect has been shown to be effective from the start of plastic deformation. Accordingly, the m values determined in continuous tensile tests were negative in the entire strain range, and also vary in dependence on the gain size or strain rates used for calculating them. After low rolling reductions ( lt 20%) and subsequent annealing, a well defined subgrain structure has been revealed, which seems to improve the strain hardening ability of the tested material, and influence the overall strain rate sensitivity.