Role of tension twins on warm deformation behavior of AZ31 Mg alloy

Abstract

Magnesium alloys have recently generated great interest in auto as well as electronic industries due to their potentials as lightweight structural materials. Their applications have, however, been severely limited to date because of their poor formability at room temperature, inherent in HCP crystals having insufficient slip systems. Twinning is, therefore, known to play an important role on plastic deformation in wrought magnesium alloys. Tension twinning the most easily-activated has been reported to show different characteristics depending on the loading conditions. For example, twin morphology and fraction depend on loading condition to exhibit different flow stress and strain hardening behavior. In this study, role of tension twins has been investigated during warm deformation under a compressive loading perpendicular to c-axis and tensile loading parallel to c-axis. The mechanisms of dynamic re-crystallization (DRX) during warm deformation have also been investigated in relation to the different twinning characteristics depending on loading conditions. All the tests were conducted at 250 ˚C under the strain rate of 0.01/s.