Cold workability and shape memory properties of novel Ti–Ni–Hf–Nb high-temperature shape memory alloys

The effect of Nb content on the cold workability, microstructure and shape memory properties of Ti–Ni–Hf–Nb alloys is investigated. The addition of Nb to Ti–Ni–Hf improves the cold workability due to the formation of a soft Nb-rich phase. The Ti–Ni–Hf–Nb alloys exhibit a high-temperature shape memory effect during heating and cooling cycles under various stress levels. As the Nb content increases, the shape memory properties of the Ti–Ni–Hf–Nb alloys become more stable although the shape recovery strain decreases.