Evolution of microstructure, texture, and mechanical performance of Mg-13Gd-2Er-0.3Zr alloy by double extrusion at different temperatures

Abstract

This study investigates a novel Mg-13Gd-2Er-0.3Zr (weight percent) alloy, focusing on the influence of varying double extrusion temperatures (390 °C–450 °C) on the evolution of grain structure, texture, and mechanical properties of double-extruded (DE) alloys. Results show that double extrusion markedly refines the recrystallized grains and enhances the dispersion of fine secondary precipitates, thereby significantly improving the tensile properties compared to a single extruded alloy. A notable increase in the dynamic recrystallization (DRX) and grain size is observed as the deformation temperature rises, with grain sizes enlarging from 2.2 µm at 390 °C to 10.2 µm at 450 °C. The DE alloy extruded at 390 °C demonstrates superior mechanical properties, which was attributed to the synergistic effects of refined recrystallized grains, the presence of un-recrystallized (un-DRXed) grains, abundant fine precipitates, and a weakened basal texture. Additionally, this study highlights that a lower fraction of fine precipitates and a higher fraction of DRX grains contribute effectively to the improvement of elongation (EL) in DE alloys which is ~ 75% higher in the DE alloy at 430 °C than the single extruded alloy. This comprehensive analysis underscores the critical role of extrusion temperature in tailoring the microstructure and mechanical performance of Mg-13Gd-2Er-0.3Zr alloy, offering valuable insights for optimizing the properties of magnesium alloys for industrial applications.