How high should the temperature be added during the heat treatment of Nitinol?

Nickel-titanium-based alloys are memory alloys whose memory effect is due to thermoelastic or stress-induced martensitic transformation in the alloy. Therefore, the key to heat treatment is to ensure the transformation of the material in the material but the martensite is maintained and the martensite morphology is maintained after the heat treatment. The TiNi-based alloy transformation belongs to the body-centered cubic B2 phase to martensite transformation. The transition temperature is different due to its composition. Generally used: 800-850 ° C quenching, then, 400-500 ° C × T aging water quenching. The aging temperature and time have a great influence on the memory effect.