Texture Formation through Thermomechanical Treatment and Its Effect on Superelasticity in Mg–Sc Shape Memory Alloy

Abstract

The formation of texture through thermomechanical treatment was investigated in Mg–18.8 at% Sc shape memory alloy to enhance its superelasticity at room temperature. The samples were cold rolled in an α phase or in a β phase and then finally heat treated at 690°C followed by water quenching to obtain a β phase. In the case of cold rolling in the α phase, a basal-plane texture was formed, while no preferential texture was observed along in-plane direction. After the final heat treatment, {011}〈uvw〉_β transformation texture was obtained, according to Burgers relationship, indicating no improvement of the superelasticity along in-plane direction. In the case of the cold rolling in the β phase, a weak {111}〈011〉_β recrystallization texture was obtained. The sample showed about 0.65% superelastic tensile strain along rolling direction, while that along transverse direction (//∼〈113〉β) showed only about 0.43%. This trend is in good agreement with the orientation dependence of the transformation strain, but, the obtained superelastic strain was much lower than the expected value, which is due to the weak texture and suggests the existence of a strong grain constraint in the Mg–Sc shape memory alloy.

 

This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 84 (2020) 253–259.