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采用快速ＬＭＴＯＣＰＡ方法分别计算成分有序和无序的ＴｉＡｌ合金（Ｌ１０结构）的热力学性质，通过比较可以发现，有序情况下的ＴｉＡｌ合金的晶格常数理论值与实验值符合很好，而无序情况下的晶格常数理论值与实验值偏差大于３％．理论结果表明有序的γＴｉＡｌ相在富Ａｌ区，多余的Ａｌ原子占据Ｔｉ的格点后，系统能量降低，有利于γＴｉＡｌ相的稳定性，而在富Ｔｉ区，多余的Ｔｉ原子占据Ａｌ的格点后，将使所有的Ｔｉ原子的能量增大，使系统能量升高，不利于γＴｉＡｌ相的稳定性，而有利于新相的形成．
The thermodynamic properties of the ordered and disordered TiAl alloy (L10 structure) were calculated by the fast LMTOCPA method. It can be found by comparison that the theoretical value of the lattice constant of TiAl alloy in good agreement with the experimental value is very good, The disordered cases of lattice constant theoretical value and experimental deviation of more than 3%. The theoretical results show that the ordered γ-TiAl phase is in the Al-rich region and the excess Al atoms occupy the lattice points of Ti, which reduces the energy of the system and is favorable for the stability of the γ-TiAl phase. In the Ti-rich region, excess Ti atoms Occupy Al lattice point, will make all the Ti atom energy increases, the system energy is not conducive to the stability of γ TiAl phase, and is conducive to the formation of a new phase.