Influence of applied stress on the transformation behaviour and martensite evolution of a Ti-Ni-Cu shape memory alloy

► In-situ synchrotron diffraction study of martensite evolution in a Ti-Ni-Cu SMA transforming under stress. ► Non-linear stress-strain behaviour related to B19 → B19′ and the mechanical detwinning of B19′. ► Thermal cycling causes texture evolution in both martensites accompanied by sample elongation. ► Significant sample elongation during cooling occurs during B2 → B19 transformation. ► Variant selected martensite texture similar to that achieved by mechanical detwinning.