EFFECTS OF HEAT TREATMENT ON TENSILE PROPERTIES AND SHAPE MEMORY EFFECTS OF Ni-Ti-Nb ALLOY
(School of Materials Science and Engineering; Harbin Institute of Technology; Harbin 150001)
Abstract: The effects of heat treatment on tensile properties and shape memory effects of Ni-Ti-Nb alloy have been studied by tensile test at different temperatures and electrical resistance measurement. It has been shown that below 900 ℃ with the increase of solid solution temperature, cooling rate and aging temperature, yield stress decreases whereas elongation increases; yet above 900 ℃,yield stress shows no substantial change whereas elongation decreases abruptly. Once specimens deformed at ( Ms+30 ℃) to 16%, transformation hysteresis width around 150 ℃ can be achieved and shape recovery ratio still remains 70%～80% no matter which kind of heat treatment is taken.
Key words: Ni Ti Nb alloy heat treatment tensile properties shape memory effect