The effect of grain size on texture evolution and mechanical properties of an AZ31 magnesium alloy during cold-rolling process

Abstract

Cold-rolling experiments were conducted on AZ31 hot-rolled plates with small (∼5 μm) and large grains (∼50μm). The evolution of microstructure, texture and their effects on the mechanical properties were studied. After cold-rolling, plenty of {101¯1} twins were observed in the large grain samples while some shear bands were more evident in the small grain samples. Non-basal a⇀+c⇀ slip was considered to be the dominating deformation mechanism in small grain sample and led to an inclined basal texture (±15°) with double peaks after rolling. However, with an inclined basal texture, the strength still increased significantly and the failure strain decreased to 9.7% in compression test. The potential softening effect was compensated by a⇀+c⇀ dislocation related work hardening. In large grain sample with high volume fraction of {101¯1} twins, both the yield strength and failure strain were higher than the original plate with small grains. Twinning related texture weakening effect was thought to contribute to the higher failure strain in cold-rolled large grain sample.