Characteristics of Ti50Pd30Ni20 high-temperature shape memory alloy

Abstract The decrease in critical stress for slip with increasing temperature leads to the introduction of permanent strain and thus deteriorates shape memory (SM) characteristics of high-temperature SM alloys. Thermomechanical treatment consisting of cold-rolling and subsequent annealing at various temperatures, was applied for the first time to improve the high-temperature SM characteristics of the Ti 50 Pd 30 Ni 20 alloy. Then, a systematic study of transformation temperatures, microstructure and associated mechanical behaviour at 443–548K was carried out. The remarkable improvement in SM characteristics was found for the alloy cold-rolled to 24–25% reduction in thickness and annealed at 673K for 3.6 ks. In addition, superelasticity was observed for the first time in this alloy. Finally, the key factor for improvement of high-temperature SM characteristics in the alloy is pointed out.