Thermodynamic analysis of the compounds in heat resistant steels based on the CALPHAD method

用calphhad方法对高铬铁素体钢中相的吉布斯能函数进行了热力学评价。从3a到3b基团的各种过渡元素组合，通过从头计算估计了基态MX相和Z相的生成焓。其中，含有Ta-、Sc-、V-族元素的Z相的生成焓极低。这表明它们非常稳定；因此，这些Z相可以代替细小分散的MX相作为高铬铁素体钢的强化因子。计算得到的相平衡与商业实验数据（T91）吻合较好。经评估的相吉布斯能量函数已通过“NIMS热力学数据库”网站向公众开放。从网站上，可以下载数据库文件并复制当前的结果。

The Gibbs energy functions of the phases in the high-Cr ferritic steels have been assessed thermodynamically using the CALPHAD method. Formation enthalpy of the MX and Z phases at the ground state were estimated from ab initio calculations in various combinations of transition elements from 3a to 3b groups. Of the combinations, the Z phase with Ta-, Sc-, V- group elements exhibited very low formation enthalpy. This suggests that they are significantly stable; thus these Z phases can be used as a strengthening factor of the high-Cr ferritic steels instead of the fine dispersed MX phases. The calculated phase equilibria are in good agreement with experimental data of the commercial ally (T91). The assessed Gibbs energy functions of the phases have been opened for public through the website named "NIMS thermodynamic database". From the website, the database files can be downloaded and reproduce the present results.