Deformation mechanism of highly textured AZ31 sheet under high strain rates

Abstract

In this study, in‐plane tension behavior of AZ31 magnesium sheet was measured in rolling direction, transverse direction and 45° direction under high strain rates of 600 s‐1, 1200 s‐1 and 2400 s‐1 at room temperature using a Split Hopkinson Tension Bar (SHTB). The microstructures after high strain rates deformation were observed by optical micrography. The anisotropic behavior was negligible and marginally positive strain rate effects were observed in all deformation directions. Texture analysis of the sheet demonstrated that three possible deformation mechanisms could apply to AZ31 magnesium alloy sheet under high strain rates tension, those are {101‾1} contraction twinning and/or {101‾1} ‐{101‾2} double twinning, prismatic slip and <c+a> pyramidal slip. The volume fraction of twinning was decreased with strain rate increasing. Dynamic recrystallization took place upon the strain rate of 2400 s‐1 and the dynamic recrystallization mechanism was attributed to the twinning‐induced dynamic recrystallization.