Texture tailoring of a cold-rolled Mg-Zn-Gd alloy by electropulse treatment: The effect of electropulse and Gd element

Abstract

Electropulse treatment (EPT) was utilized to tailor the texture of a cold-rolled Mg-rare earth (RE) alloy (Mg-1Zn-1Gd, ZG11). The respective effect and combined effect of electropulse and Gd element on the texture modification were evaluated by using conventional heat treatment (HT) and AZ31 alloy for comparison. It was found that in addition to significantly accelerating static recrystallization (SRX), electropulse was effective in suppressing the growth advantage of basal oriented grains and facilitating uniform growth, according to the evolution of 30° 〈0001〉 boundaries. As widely reported, addition of Gd element was observed to promote shear band-related nucleation and preferential growth of off-basal oriented grains via grain boundary segregation; unfortunately, the growth advantage of basal oriented grains seemed not to be well-suppressed. When electropulse was exerted on cold-rolled ZG11, the SRXed grains showed obvious off-basal orientations at the early stage benefited from various nucleation sites, e.g., shear bands, extension twin boundaries, and the off-basal orientations were retained to a great extent during grain growth due to the synergetic effect of electropulse and grain boundary segregation on grain boundary migration. As a consequence, the ZG11 alloy evolved into a quite distinctive SRX texture after EPT.