Effect of gadolinium on the deformation and recrystallization behavior of magnesium crystals

Single crystals of pure Mg and Mg-0.8 wt% Gd alloy oriented for non-basal slip were deformed in plane strain compression at room and elevated temperatures to investigate activation of prismatic and pyramidal ( c + a ) slip in both materials. Compression along the c-axis of Mg-Gd single crystals revealed no marked improvement in room temperature ductility compared to pure Mg because there was no notice-able increase in ( c + a ) slip activity. At room temperature, Mg-Gd single crystals fractured along { 11 2 over bar 4 } planes, which was the same fracture habit for pure Mg. Compression perpendicular to the c-axis, where specimens were favorably aligned for prismatic slip, exhibited cooperative extension/compression twinning and no notable increase in prismatic slip activity. Although the addition of Gd did not promote activation of non-basal slip, it had a significant impact on continuous dynamic recrystallization. It is concluded that the improved formability in polycrystalline Mg-Gd alloys must be primarily attributed to a change in recrystallization behavior and its effect on texture, rather than the activation of additional slip modes. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Single crystals of pure Mg and Mg-0.8 wt% Gd alloy were compressed at room and elevated temperatures to study the activation of prismatic and pyramidal (c+a) slip. The addition of Gd did not increase (c+a) slip activity, but had a significant impact on continuous dynamic recrystallization in Mg-Gd alloy. The improved formability in polycrystalline Mg-Gd alloys is mainly attributed to changes in recrystallization behavior and its effect on texture.