热处理对CuAlNiMnTi形状记忆合金相变滞后的影响

Influence of heat treatment on transformation hysteresis of CuAlNiMnTi shape memory alloys

用电阻法、金相分析、电镜分析及Ｘ射线衍射等研究了热处理对ＣｕＡｌ－ＮｉＭｎＴｉ形状记忆合金相变滞后（Ａｆ—Ｍｓ）的影响．研究结果表明：淬火合金时效处理时，相变点急剧下降，时效初期相变滞后明显增大，后趋于稳定．淬火合金６００℃中温处理时，相变点下降，相变量减小．而热弹性马氏体相变类型则从Ｉ型转变到Ⅱ型，然后再转变到Ｉ型；伴随着热弹性马氏体相变类型的变化，相变滞后开始降低，然后增加．这是因为时效处理时析出ＮｉＡｌ基相，中温处理时析出ａ相所致．

The electrical resistance method, metallograph analysis, TEM observation and X-ray diffraction analysis are employed to investigate influence of heat treatment on the transformation hysteresis ( Af- Ms) of CuAlNiMnTi shape memory alloys (SM As). It is shown from the investigation that when the quenching specimens are subjected to aging treatment, the transformation temperature is decreased and the transformation hysteresis is enlarged at the first, and then trended towards stability; when the quenching specimens are subjected to moderate-temperature treatment at 600°C ,the transformation temperature is decreased and the amount of transformation is decreased. The type of thermoelastic martensitic transformation changes from Type I to Type I and then to Type I again, and the transformation hysteresis decreases at first and then increases accompanying the change of the type of thermoelastic martensitic transformation. The reason lies in the fact that aging treatment leads to the precipitation of NiAl-base phase ,while moderate-temperature treatment leads to the precipitation of a phase.