深冷处理对Ni-Ti合金形状记忆效应的影响

用退火、DSC、XRD、深冷处理及机械训练等方法,对Ni(50.62%)Ti(49.38%)合金的显微组织、相变温度、相组成、形状回复率进行研究,探索提高该合金形状记忆效应的新方法。结果表明,该合金Ms点为-2℃,As点为22℃;退火态Ni-Ti合金主要由奥氏体及少量粒状的Ti3Ni4相组成;用液氮与乙醇经不同比例混合配制成的介质进行深冷处理,随着深冷温度的降低,合金的形状回复率增大;随着训练次数的增加,其回复率曲线呈抛物线状;该合金在3次机械训练-196℃深冷时回复率最好,为51.27%。

Influence of cryogenic treatment on shape memory effect of Ni-Ti alloy

Microstructure,phase transition temperature,phase composition,shape recovery ratio of Ti-50 62%Ni alloy were studied to explore the new method of increasing the shape memory effect of this alloy by annealing,DSC,XRD,cryogenic treatment and mechanical training The results show that the phase transition point Ms of the alloy is -2 ℃ and As is 22 ℃.The main phases of the annealed alloy are austenite and a little granular Ti_3Ni_4 phase.After cryogenic treatment with liquid nitrogen and ethanol mixture in different proportions,shape recovery ratio of the alloy increases with the cryogenic temperature decreasing,shape recovery ratio curve of the alloy is parabola-shaped with training time increasing.Under the condition of 3 times mechanical training and cryogenic treatment at -196 ℃,the best shape recovery ratio of 51 27% can be reached.