热处理对TiNi形状记忆合金回复稳定性能的影响

Effect of heat treatment on stability of recovery properties of TiNi shape memory alloy

研究了热处理对TiNi合金回复稳定性能的影响。结果表明,马氏体相变温度Msσ和Mfσ随热机械循环次数增加而上升,而马氏体逆相变温度Asσ和Afσ随热机械循环次数的增加而下降。随着热机械循环次数的增加,相变温度逐步稳定。退火温度小于500℃,热机械循环下TiNi合金的回复性能稳定,退火温度达550℃时,TiNi合金组织长大,应力诱发马氏体变形时容易发生滑移,回复应变随热机械循环次数增加而下降,回复稳定性能变差。

Effects of heat treatment on stability of recovery properties of TiNi alloy were studied.The results show that Msσ and Mfσ increase with increasing number of thermo-mechanical cycles,while Asσ and Afσ decrease contrarily.The transformation temperatures become steady with increasing number of thermo-mechanical cycles.The stability of recovery properties is well with thermo-mechanical cycling when the heat treatment temperature is below 500 ℃.The grain of the TiNi alloy grows when the heat treatment temperature reaches 550 ℃.The coarse grain will be prone to slip during stress induced martensite deformation,and it will result in the decrease of recoverable strain with increasing number of thermo-mechanical cycles.