TiNiZr高温形状记忆合金的马氏体相变和相稳定性的理论研究

Study on Phase Stability and Martensitic Transformation of Ti Ni Zr High-temperature Shape Memory Alloys from First-principles Calculations

采用基于赝势平面波方法的第一性原理计算,详细研究了Ti Ni Zr高温形状记忆合金的相稳定性、弹性和电子结构等性质。结果表明,由于较低的形成能,添加的Zr元素优先占据Ti Ni合金的Ti位。少量Zr含量的添加,Ti Ni Zr合金的相稳定性增强,然后随着Zr含量的增加而降低。根据Ti Ni Zr合金B2相的弹性系数讨论了Ti Ni Zr合金的马氏体相变温度和相变类型。弹性系数C44对Ti Ni Zr合金的马氏体相变温度有很大的作用。Ni d态和Zr d态杂化作用的增强导致了马氏体相变温度的升高。

Phase stability,elastic property and electronic structure of Ti Ni Zr high-temperature shape memory alloys have been investigated by first-principles calculations by using the pseudopotentials plane-wave method. The results showed that the added Zr preferentially occupies the Ti sites in Ti Ni alloy due to the lowest formation energy. The phase stability of Ti Ni Zr alloys first increased with a small addition of Zr and then decreased with the increasing of Zr content. Based on the elastic constants of the Ti Ni Zr alloys with B2 phases,the martensitic transformation temperature and transformation type were discussed. The elastic constant C44 had the great effect on the martensitic transformation temperature of the Ti Ni Zr alloys. The increase of the martensitic transformation behind the elastic properties resulted from the stronger hybridization between Ni d and Zr d states.