Stress-induced transformation behaviors at low temperatures in Ti-51.8Ni (at. %) shape memory alloy

Martensitic transformation behaviors at low temperatures in polycrystalline Ti-51.8Ni (at. %) alloy were investigated with compressive stress. Superelasticity with almost complete shape recovery was confirmed at temperatures of 40–180 K. In stress-induced transformation at fixed temperatures, while the reverse transformation finishing stress monotonically decreased with decreasing test temperature, the forward transformation starting stress changed from decrease to increase at about 125 K. Forward and reverse transformation temperatures evaluated under constant stresses of 50 and 750 MPa were generally coincident with the results determined at the constant temperatures, where “heating-induced forward transformation” was confirmed under a stress of 750 MPa.