The effects of compressive pre-deformation on yield asymmetry in hot-extruded Mg-3Al-1Zn alloy

The effects of compressive pre-deformation along extrusion direction (ED) on yield asymmetry between tension and compression in hot-extruded Mg-3Al-1Zn (AZ31) alloy was investigated in this paper. {10-12}-type twinning occurred when samples were subjected to compressive pre-deformation. The compressive yield strength of sample with compressive pre-deformation increased gradually with the increase in compressive prestrain. The tensile yield strength of the sample decreased rapidly with the increase in compressive prestrain from zero to ~1.7%, but it was nearly unaltered when compressive prestrain was higher than ~1.7%. Detwinning occurred in the twinned regions played roles in the subsequent tensile process so that the yield stress was lower than sample without prestrain. Yield asymmetry between tension and compression decreased gradually when compressive prestrain was lower than ~1.1%, but it began to increase after that. It suggests that yield asymmetry can be effectively controlled by appropriate pre-deformation.