Influence of Heat Treatment on Phase Transformation of NiTi Shape Memory Alloys

50.8%Ti-Ni shape memory alloys are heat treated at different temperatures for different times and the temperature of transformation is measured with DSC.The A_f of NiTi shape memory alloys decreased around 20℃ to 30℃and the M_s of the alloys changed little through heat treatment.The influence of heat treatment on the phase transformation of NiTi shape memory alloys is discussed by comparing the DSC curves.It is indicated that when aged at 300℃-500℃,the shorter the holding time,the lower the A_f,in the same time,the lower holding temperature leads lower A_f.