Microstructure and texture evolution of ECAP-processed Mg-Ce alloy during isothermal annealing

Abstract

Static recrystallization and grain growth behaviors were investigated in Mg-0.3Ce (wt%) alloy processed by equal-channel angular pressing (ECAP) for N = 1 (εeq = 0.9), 2 (εeq = 1.9), and 4 (εeq = 3.9) passes at 300 °C using route Bc and annealed at 450 °C for 5, 30, 60, and 180 min. The results demonstrated that the annealed microstructure and texture are strongly related to the strain level, second particles distribution, and fraction of dynamic recrystallization (DRX) during ECAP. At low strain (1 ECAP pass), the microstructure was very heterogeneous and the texture development changed with increasing annealing time due to the absence of sufficient recrystallization nucleation sites and pinning effect of second particles. At medium strain (2 ECAP passes), the microstructure was homogeneous, however, the texture was unstable mainly due to the limited DRX during ECAP processing leading to the preferred grain growth. At high strain (4 ECAP passes), the microstructure was homogeneous and the texture was retained throughout the entire annealing duration due to the significant amount of DRX.