Enhanced mechanical properties in fully recrystallized ultrafine grained ZKX600 Mg alloy

Abstract

Mg-Zn-Zr-Ca (ZKX600) alloy specimens with various fully recrystallized grain sizes ranging from 0.77 μm to 23.3 μm were fabricated by high pressure torsion (HPT) followed by subsequent annealing. Tensile tests carried out at room temperature revealed that ultrafine grained (UFG) specimens exhibited enhanced combinations of strength and ductility compared to their coarse-grained counterparts. Observation of deformation microstructures suggested that basal slip and {10-12} extension twinning were the dominant mechanisms during deformation of coarse grained specimens, while deformation twinning was significantly inhibited in the UFG specimens. Based on the observations it is proposed that non-basal slip activity is responsible for the enhanced mechanical properties, and should be the focus of further investigations.