Microstructure, Texture Evolution, and Strain Hardening Behaviour of As-extruded Mg-Zn and Mg-Y Alloys under Compression

Abstract

Microstructure, texture evolution and strain hardening behaviour of the Mg-1Y and Mg-1Zn (wt%) alloys were investigated under room temperature compression. Microstructural characterization was performed by optical microscopy, scanning electron microscopy, electron back scattered diffraction and transmission electron microscopy. The experimental results show that Mg-1Zn alloy exhibits conventional three-stage strain hardening curves, while Mg-1Y alloy exhibits novel six-stage strain hardening curves. For Mg-1Y alloy, rare earth texture leads to weak tensile twinning activity in compression and consequently results in a moderate evolution to <0001> texture. Moreover, inefficient tensile twinning activity and weak slip-twinning interaction give rise to excellent ductility and high hardening capacity but low strain hardening rate. For Mg-1Zn alloy, basal texture leads to pronounced tensile twinning activity in compression and consequently results in rapid evolution to <0001> texture. The intense tensile twinning activity and strong slip-twinning interaction lead to high strain hardening rate but poor ductility and low hardening capacity.

Keywords

magnesium alloy / texture / rare earth / twinning / strain hardening behavior