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

用CALPHAD方法热力学地计算了高铬铁素体钢中各相的吉布斯能量函数。通过从头计算估算了3a到3b过渡元素不同组合下MX相和Z相在基态的生成热。在这些组合中，含有Ta、Sc、V族元素的Z相具有很低的生成热容。因此，这些Z相可以代替弥散细小的MX相作为高铬铁素体钢的强化因子。计算的相平衡与工业联盟(T91)的实验数据符合得很好。各相的吉布斯能量函数已通过名为“NIMS热力学数据库”的网站向公众开放。可以从该网站下载数据库文件，并复制目前的结果。

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.