Room temperature deformation behaviour of A1Mg6.5 alloy sheet

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 annea ling at 320 degrees C/3 h. The applied working conditions were found to aff ect the yield point elongation, dynamic strain aging and the related steady state strain rate sensitivity. The Portevin-LeChatelier effect has been sh own to be effective from the start of plastic deformation. Accordingly, the m values determined in continuous tensile tests were negative in the entir e strain range, and also vary in dependence on the gain size or strain rate s used for calculating them. After low rolling reductions (<20%) and subseq uent annealing, a well defined subgrain structure has been revealed, which seems to improve the strain hardening ability of the tested material, and i nfluence the overall strain rate sensitivity.