A model for the grain refinement mechanism in equal channel angular pressing of Mg alloy from microstructural studies

AZ31 Mg alloy samples were processed by the equal channel angular pressing (ECAP) process at 200 °C for up to four passes. Microstructural evolution during ECAP was studied systematically using optical microscope and transmission electron microscope. Using data observed from the microstructure analysis, a model for the grain refinement mechanism of Mg during ECAP is proposed. Multiple pass ECAP was also conducted at different temperatures to further confirm the proposed model.