Uncovering of the formation of rare earth texture and pseudo fiber bimodal microstructure in the high ductility Mg-2Gd-0.4Zr alloy during extrusion

Abstract

The aim of this research was to elucidate the underlying mechanism involved in the formation of rare earth (RE) texture and pseudo fiber bimodal microstructure in the high ductility Mg-2Gd-0.4Zr alloy. The microstructure and texture evolution during the extrusion process were analyzed using various techniques, including optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and electron probe microanalysis (EPMA). The findings revealed that the RE texture in the extruded Mg-2Gd-0.4Zr alloy emerged during the dynamic recrystallization (DRX) process and was further strengthened during the subsequent static recrystallization and grain growth processes. The nucleation and growth of grains in the streamline region of Zr particles were delayed in comparison to other regions due to the pinning effect of Zr particles, ultimately resulting in the formation of pseudofiber bimodal microstructure in the extruded Mg-2Gd-0.4Zr alloy.