Texture evolution and effect on mechanical properties of repetitive upsetting-extruded and heat treatment Mg-Gd-Y-Zn-Zr alloy containing LPSO phases

Abstract

The texture evolution mechanism of Mg-13.1Gd-3.9Y–2Zn-0.4Zr (wt%) alloys during reciprocating upsetting extrusion (RUE) and subsequent heat treatment were investigated in this study. The relationship between texture weakening and deformation mechanism during multi-pass deformation was further discussed. The results show that the strong (0001)∥ED basal texture was formed after RUE, which decreases with the increase of deformation passes; the texture type had no obvious change after T5 treatment, and the texture intensity decreases significantly after T6 treatment. The high proportion of deformed grains determines the formation of strong basal texture after a single pass deformation. Due to the strong anisotropy of LPSO phases, deformed grains with different initial orientations participate in deformation through kinking or activation of basal slip and prismatic <a> slip, respectively, and have different effects on the final texture components. With the strain increases (2 P), the deformed grains are consumed by DRXed grains with random texture, and the non-basal slip of DRXed grains became the main deformation mechanism. After T6 heat treatment, the < 112̅0 > fiber texture components were formed in the sample, which is due to the random nucleation and preferential growth of recrystallized grain during solution treatment. The mechanical properties of the alloys are significantly improved after RUE deformation, but the improvement on ED is better than that on TD. The mechanical properties of the alloys are improved by T5 or T6 heat treatment. The anisotropy of the former is still maintained, while that of the latter is basically eliminated.