Effect of extrusion ratio on microstructure, texture, and mechanical properties of dual-phase Mg−8Li−6Zn−2Gd alloy

Abstract

The microstructure observation, macrotexture analysis, and tensile test were conducted to investigate the effect of extrusion ratio on the microstructure, texture, and mechanical properties of Mg−8Li−6Zn−2Gd alloy. The results show that the as-homogenized Mg−8Li−6Zn−2Gd alloy consists of α-Mg, β-Li, MgLiZn, I-phase, and W-phase. After hot extrusion, eutectic I-phase is broken into fine particles, while W-phase maintains massive shape. Both α-Mg and β-Li matrices undergo dynamic recrystallization (DRX), and their grains gradually refine with increasing extrusion ratio. For α-Mg matrix, the weakening of basal texture and the strengthening of prismatic texture after hot extrusion are due to the activation of non-basal slip. For β-Li matrix, the appearance of obvious α and γ fiber textures after hot extrusion is associated with the dynamic recovery (DRV) and DRX. The tensile strength and elongation of the alloy are simultaneously improved by hot extrusion, and the best comprehensive mechanical properties are achieved when extrusion ratio is 16:1.