We have investigated four models for calculating the contribution of an applied magnetic field to the free energy of Fe and Fe alloys—Weiss Molecular Field Theory (WMFT), Kuz’min, Arrott, and Curie-Weiss. On the basis of these models, the shifts in phase transformation including both ferromagnetic and paramagnetic phases as a function of magnetic field and alloy content can be predicted. The Kuz’min model is easiest to solve and is also best able to predict the trends in experimentally observed shifts in ferrite/austenite phase transformations for Fe-based alloys under an applied magnetic field both below and near the Curie temperature. For phase transformations above the Curie temperature, the predictions using the Curie-Weiss form with WMFT parameters, here extended to alloy systems, are in good agreement with experimental results. Different aspects of the four models have been discussed in detail with a view to developing a reliable methodology to predict shifts in phase diagrams as a function of alloy content.

我们研究了四种模型，用于计算施加的磁场对Fe和Fe合金的自由能的贡献-Weiss分子场论（WMFT），Kuz'min，Arrott和Curie-Weiss。在这些模型的基础上，可以预测包括铁磁相和顺磁相在内的相变随磁场和合金含量的变化而发生的变化。Kuz'min 模型最容易求解，并且也最能预测实验观察到的铁基合金在低于和接近居里温度的磁场下铁素体/奥氏体相变的变化趋势。对于居里温度以上的相变，使用带有 WMFT 参数的居里-魏斯形式的预测，这里扩展到合金系统，与实验结果非常一致。