Effect of initial orientation on bending behavior in rolled AZ31 magnesium alloy

This study investigated the influence of initial grain orientation on the room-temperature bending behavior of rolled AZ31 magnesium alloy. The results indicated that the rolling direction (RD) specimen exhibited superior bending strength (with yield strength of 149 MPa vs. 120 MPa, and peak stress of 413 MPa vs. 358 MPa, respectively) and bending ductility (with a fracture bending angle of 75° vs. 131°, corresponding to punch displacements of 14.8 mm vs. 6.4 mm) compared to the normal direction (ND) specimen. This macroscopic performance difference originated from the anisotropy of microscopic deformation mechanisms, particularly the spatial distribution of dominant {10−12} tensile twinning activation regions. The primary twinning zone in the RD specimen was located in the compression region on the inner side of the bent specimen, whereas in the ND specimen, it was concentrated in the tension region on the outer side. The interaction between the initial c-axis preferred orientation of the grains and the local stress state determined twinning activation, as well as the synergy and competition of dislocation slip, thereby governing the significant bending formability anisotropy.