Thermal cycling stability and two-way shape memory effect of Ni–Cu–Ti–Hf alloys

Abstract Thermal cycling stability and shape memory effect (SME) of quarternary Ni–Cu–Ti–Hf alloys (Ni 45 Cu 3 Ti 37 Hf 15 , Ni 43 Cu 7 Ti 35 Hf 15 and Ni 40 Cu 10 Ti 40 Hf 10 ) have been studied. The Ni 45 Cu 3 Ti 37 Hf 15 and Ni 43 Cu 7 Ti 35 Hf 15 alloys are high-temperature shape memory alloys with good thermal stability. Although the thermal cycling stability of Ni 40 Cu 10 Ti 40 Hf 10 is better than the other two alloys, its phase transformation temperatures are below 373 K. All the three alloys can express two-way SME. A novel two-way SME has been observed in Ni 40 Cu 10 Ti 40 Hf 10 alloy.