Microstructure and mechanical properties of Mg-6.75%Zn-0.57%Zr-0.4%Y-0.18%Gd sheets by unidirectional and cross rolling

Abstract

Microstructure and mechanical properties of the Mg-6.75%Zn-0.57%Zr-0.4%Y-0.18%Gd sheets processed by unidirectional and cross rolling were investigated. Compared with the unidirectional rolling (UR) sheet, cross rolling (CR) sheet exhibits finer grain size, weaker basal texture, higher recrystallized volume fraction and higher strength. Meanwhile, the UR sheet shows strong mechanical anisotropy, while the approximate mechanical isotropy is successfully achieved in the CR sheet. Cross rolling effectively reduced the anisotropy of mechanical properties. The finer grains in the CR sheet are responsible to its higher yield strength. The anisotropy of yield strength results from the basal <a> slip, while the activation of prismatic <a> slip reduced this anisotropy. The recrystallized components in the CR sheet weaken basal texture, thereby reducing anisotropy.