朗道理论对铁氮相变的研究

Investigation of Landau theory on the iron-nitrogen phase transformation

应用朗道理论，通过引入序参量η，即单位体积中位矢（1／2，1／2，1／2）处晶格位置上被氮原子占有几率，将热力学势函数按η展开，讨论了η和温度T之间的关系。研究了αFe－γ｀Fe4N相变的位相关系并预测了相变过程申含有亚稳相出现。还应用点群理论推导了γ｀FenN相的形状。

The order-parameter η and the probability of the position vector （1/2,1/2,1/2） of the crystal lattice possessed of the nitrogen atom were introduced in the paper. And spreading out a thermodynamic potential energy function according to η. This paper was mainly to discuss the relationship between q and the temperature T by making use of Landau＇s phenomenological theory. The orientation relations of aFe-γFe4N phase transformation had been investigated and the emergence of metastable phase had been predicted. The shape of γ Fe4N was also discussed by virtue of the point group theory.