The microstructure evolution and abnormal yield asymmetry of extruded Mg-10Gd-0.5Zr alloy

Abstract

The Mg-10Gd-0.5Zr alloy had a bimodal microstructure and abnormal yield asymmetry (CYS/TYS = 1.4) after extrusion. In this paper, we discussed the origin of this asymmetry and researched the microstructure and texture variation after tensile and compression using EBSD analysis. The deformed grains exhibited intensive basal texture (//ED), while the fine DRXed grains showed weak or even random texture. The maximum MUD value of unDRXed grains increased during tension and decreased due to twinning during compression. It was found that the dislocation slip dominated both tensile and compressive deformation. The deformed grains mainly occurred prismatic slip and the DRXed grains were basal slip. Numerous DRXed grains undertaken the main deformation task. Suppression of extension twinning and strain localization were the secondary and main reasons for this abnormal yield asymmetry.

Keywords

• Mg-Gd alloys
• Bimodal microstructure
• Yield asymmetry
• Strain localization