Microstructure and texture evolution of Mg-RE-Zn alloy prepared by repetitive upsetting-extrusion under different decreasing temperature degrees

The repetitive upsetting-extrusion (RUE) experiments of Mg-RE-Zn alloy were carried out to study the grain refinement and texture evolution under different decreasing temperature degrees during the deformation process. The results showed that during the RUE processing, the samples underwent dynamic recrystallization (DRX) and exhibited the similar bimodal microstructure comprising coarse deformed grains and fine dynamic recrystallized grains around. The continuous dynamic recrystallization (CDRX) process and the discontinuous dynamic recrystallization (DDRX) process occurred simultaneously, promoting grain refinement. The particles and the second phases precipitated, which effectively induced DRX to occur through the particle-stimulated nucleation (PSN). As the degree of decreasing temperature and the initial deformation temperature increased, the average grain size and texture intensity of the alloy decreased because the volume fraction of DRXed grains with small grain size and weak texture increased. (C) 2019 Elsevier B.V. All rights reserved.