The Dynamic Recrystallization and Elevated-Temperature Work Hardening Behavior of Mg-Y-Sn Alloys

Abstract

The dynamic recrystallization (DRX) and elevated-temperature work-hardening behavior of Mg-Y-Sn alloys with various Y contents were investigated. The results demonstrated that the Mg-6Y-0.5Sn alloy was dominated by continuous DRX and accompanied by discontinuous DRX during the process of hot extrusion, which further contributed to a small proportion of DRXed grains (59%) and increased coarse unDRXed grains, compared to the counterpart of Mg-2Y-0.5Sn and Mg-5Y-0.5Sn alloys. Correspondingly, the initial work hardening rate of Mg-6Y-0.5Sn alloy was improved by the raised unDRXed grains component with high-density residual dislocations, contributing to strengthening. At 300 °C, high residual strain provided the driving force and weakened texture promoted slip for subsequent DRX occurrence with dislocation annihilation, leading to a decreased 10% work hardening rate and obvious dynamic softening in Mg-6Y-0.5Sn alloy.

Keywords: Mg-Y-Sn alloy, Dynamic recrystallization behaviors, Elevated-temperature work hardening, Microstructures