钛铝合金热力学性质的研究

Investigation on the Thermodynamic Properties of Ti Al Alloy

采用快速ＬＭＴＯＣＰＡ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γＴｉＡｌ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γＴｉＡｌ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γＴｉＡｌ相的稳定性，而有利于新相的形成．

The thermodynamic properties of ordered and disordered Ti Al alloys with structure L 10 were calculated by fast LMTO CPA method respectively. Comparing the results,it was found that the theoretical result of the lattice constant of the ordered TiAl alloy accorded well with the experiential result,while the theoretical result of the lattice constant of the disordered TiAl alloy deviated about 3% from the experiential result. The theoretical results show that in Al rich region of the ordered TiAl alloy,the surplus atoms of Al which occupy the lattices of Ti will decrease the energy of the system,in favour of the stability of γ TiAl phase,while in the Ti rich region,the surplus atoms of Ti which occupy the lattic of Al will increase the energy of the system,which disfavors the stability of γ TiAl phase,and favors the formation of new phase.