Ni Ti合金具有优异的形状记忆功能和良好的生物体兼容性,近年来对它的应用研究受到工程界和医学界的重视,同时对Ni Ti合金形状记忆效应的微观机制的研究也在逐步深入。介绍了Ni Ti合金的主要特性及影响其形状记忆功能的主要因素,总结了Ni Ti合金的形状记忆效应和超弹性的微观机制研究现状,并指出了需对该合金进一步研究的一些问题。
Information of defects and 3d electrons in transition metals (Ti,V,Cu) and TiAl-based alloys (Ti50Al50,Ti50Al48V2,Ti50Al48Cu2) can be extracted from the positron lifetime and coincidence Doppler broadening spectra. The results show that the 3d electron signals for the transition metals Ti,V and Cu increase with the number of 3d electrons. The 3d electron signal and the electron density for binary TiAl alloy are relatively low due to the (Ti)3d-(Al)3p interactions. The addition of V and Cu atoms to TiAl alloy leads to the increase in the electron densities in bulk and the defects on grain boundaries simultaneously,as well as the enhancement of the 3d electron signal. The 3d electron signal in the spectrum of Ti50Al48Cu2 alloy is higher than that of Ti50Al48V2 alloy.
DENG WenCHEN ZhenYingJIANG HaiFengSUN ShunPingZHU YingYingHUANG YuYang
