Unveiling the ductility enhancement mechanisms in AZ31 magnesium alloy achieved via shear strain-assisted twin orientation regulation

Abstract

The ductility enhancement mechanisms were investigated in AZ31 magnesium alloy based on the newly proposed concept of shear strain-assisted twin orientation regulation (SATOR). The simple shear strain was imposed on pre-twinned samples with various strain levels to rotate the twin orientation. The results indicated that the fracture strain of SATORed samples with the greatest ductility improvement was ∼1.5 times higher than that of the original material. Overall shear-deformed samples generated a bimodal fine-grained structure. While the preferred texture of the as-received alloy was only deviated by ∼12° during shear deformation, the pre-twinned samples obtained a closed-45° shear texture. Furthermore, combining the simulation results of the visco-plastic self-consistent (VPSC) model, the improved ductility is mostly ascribed to the efficient regulation of initial twin orientation, the promoted basal slip activity, and bimodal fine-grained structure. The SATOR method has been proved to be a promising strategy for dramatically increasing ductility while also providing the reference required for texture control via twin orientation regulation in Mg alloys.