L10-TiAl基本物性的计算与比较研究

为了从理论上进一步揭示L10型TiAl金属间化合物的本征物性,采用第一原理赝势平面波方法,计算了L10型TiAl金属间化合物的平衡晶格常数、合金结合能、形成热、弹性常数以及点缺陷形成能,并与其他计算方法和实验测试的结果进行了比较.点缺陷形成能的分析结果表明,富Ti合金易出现Ti反位缺陷,富Al合金易出现Al反位缺陷;双空位形成能的分析结果表明,Ti-Ti最近邻双空位形成能最低,表明这种Ti-Ti最近邻双空位最稳定.基于晶体总电子态密度与各原子分波态密度等电子结构信息,对上述计算结果进行了初步分析.

A comparison on basic physical properties of L10-TiAl calculated by first-principles methods

In order to further disclose the basic physical properties of L10 -TiAl intermetallic compound in theory, several basic physical parameters, ie. equilibrium lattice constant, binding energy, heat of formation, elastic constant and point defect forming energy are calculated by first principles plane-wave pseudopotential methods. And a comparison with previous experimental values and other calculation results are also made. Based on the analysis of the point defect forming energy, it is found that the point defect in the rich-Ti alloy is mainly Ti antiposition, while in the rich-Al alloy most of which are Al antiposition. In terms of the calculation results of double vacancy energy of forming, we find there is the lowest double vacancy forming energy as the nearest neighbor atom of Ti being Ti. That means the Ti -Ti nearest neighbour double vacancy is most stable relative to other double vacancy defective structure. For the present calculation results, a roughly analysis is made by the electron structural information of L10 - TiAl intermetallic compound which originates from the total DOS of crystal and partial DOS of corresponding atoms.