Deformation mechanisms of a rolled Mg–6Al–3Sn alloy during plane strain compression

Abstract

Plane strain compressions were conducted on a rolled Mg–6Al–3Sn (AT63) alloy plate along the rolling direction (termed in-plane compression, IPC) and normal direction (termed through-thick compression, TTC), respectively. Deformation behaviors (mechanical response, microstructure evolution and macrotexture development) of each plane strain compression were compared against those of equivalent uniaxial compression (UC), and deformation mechanisms of IPC and TTC were investigated in detail. It has been found that the IPC with transverse constraint exhibits enhanced basal slip and retarded extension twinning with respect to the corresponding UC. However, the IPC with normal constraint transforms the main deformation mechanisms (i.e., extension twinning and basal slip) into prismatic slip and directional pyramidal slip. The TTCs, no matter with rolling or transverse constraint, suppress basal slip dramatically and cause directional contraction twins and directional pyramidal slip. The differences in deformation mechanisms between the plane strain compression and the corresponding UC are explained in relation to Schmid factor and strain directionality. Our results shed light on the deformation mechanisms of Mg alloys during plane strain compressions.