Towards enhancing the ductility of AZ31 Mg alloys by controlling twin orientation at various shear strain levels

In this work, a novel texture control strategy, shear strain-induced twin orientation regulation (SITOR), was employed to fabricate the Mg-3Al-1Zn (AZ31) alloy with significantly improved ductility. The SITOR-1P sample processed at 250 degrees C exhibited a homogeneous microstructure and an almost ideal shear texture (c-axes of grains tilted 45 degrees from the extrusion direction to the transverse direction), which resulted in an enhanced fracture elongation from 14.3% to 30.6% owing to the high activity of basal slip when compared with as-extruded Mg alloys. With increasing shear strain, the concentration of shear texture components in the SITOR-4P sample increased, leading to further improvement in its mechanical performance. While specimens produced by the conventional shear strain-induced orientation regulation (SIOR) method also underwent the same 4 passes of shear deformation, both their texture deflection and performance enhancement remained limited. The current investigation proposes a viable way to largely activate basal slip via the SITOR scheme, therefore offering a fresh perspective for addressing the poor plasticity of Mg.