Strain glass-induced switch from transformation plasticity to reversible superelasticity in Ti-Zr-Ni-Cu alloys

Reversibility of phase transformation, a basic requirement for functional properties of shape memory alloys, such as superelasticity, is severely affected by plastic deformation. Here, strain glass has been utilized to improve the reversibility of phase transformation. The incorporation of Al into Ti-Zr-Ni-Cu induces strain glass and endows the alloy with reversible phase transformation and thus ideal superelasticity. In situ x-ray diffraction and dynamic mechanical experiments were utilized to verify the mechanism for the conversion from transformation plasticity to superelasticity. This work provides a new way to improve the reversibility of phase transformation and expands the practical implications of strain glass.