Microstructure, texture and mechanical properties evolution of pre-twinning Mg alloys sheets during large strain hot rolling

Abstract

The effect of pre-twinning process on dynamic recrystallization, texture and mechanical properties of Mg alloys sheets was investigated by rolling pre-compressed AZ31 Mg sheets at 350°C. Two types of pre-compressed sheets with different initial texture component were rolled by 60% thickness reduction in a single pass for observation. Microstructure, texture and mechanical properties evolution during large strain rolling were carefully investigated. The results show that dynamic recrystallization is greatly promoted by pre-compression process. Twin structures are more effective in enhancing dynamic recrystallization than pre-deformation strain stored during compression. Besides slip, detwinning is regarded as an important deformation mode when pre-twinning samples are rolled along their compression directions. Low temperature annealing of pre-twinning samples prior to rolling hinders detwinning process, resulting in an increase of yield stress. The basal texture and plane-anisotropy are greatly weakened in the sample rolled perpendicular to the pre-compression direction. The mechanical properties of rolled sheets were promoted by pre-twinning process.