Superelasticity with low temperature sensitivity in oligocrystalline lightweight Mg-Sc shape memory alloys

As a new type of lightweight shape memory alloys (SMAs), the limited superelastic strain in Mg-Sc alloys is still an issue. Herein, the <101> orientated oligocrystalline Mg-19.1Sc alloy with nanodomains was prepared by combining hot rolling and cycling heat treatment (CHT). A large superelasticity (SE) of approximately 7.1% at 153 K was obtained, which is ascribed to the favorable crystal orientation and reduced grain boundary constraints resulting from large grain size. Moreover, the superelastic stress exhibited a small variation of 0.44 MPa K⁻¹ over a wide temperature range of 153-233 K. This work provides insight into designing high-performance superelastic Mg-based lightweight SMAs.