Mechanical Properties and Microstructural Evolution of Variable-Plane-Rolled Mg-3Al-1Zn Alloy

Abstract

The microstructural evolution and mechanical properties of AZ31 magnesium alloy produced by variable-plane rolling (VPR) were investigated. Two types of weak textures were formed: basal texture in odd pass and double-peak basal texture in even pass. Dynamic recrystallization (DRX) was observed during the VPR treatment, and the nucleation of grains during DRX was dependent on the coalescence of subgrains. Three types of twins were observed in the VPR treatment: {10-12} extension twins, {10-13} contraction twins and {10-11}-{10-12} double twins. The {10-11}-{10-12} double twinning is the underlying mechanism in the formation of the double-peak texture. Tensile testing revealed improved strength without loss of ductility. The Hall–Petch relationship can be used to describe the strengths in any even pass with the same texture. The significant strengthening is ascribed to the refined grain, twin boundaries, texture hardening, and high dislocation density.