中文摘要：

利用Thermo-Calc软件计算了高Cr铁素体耐热钢T／P91在450-1200℃区间的平衡相成分及其含量．引入合金相元素分配量的概念，研究了钢中Cr，Mo，Fe，V，Nb，C和N等主要元素随着温度变化在各平衡相中的分配特征、相稳定性、化学组成及其演化规律．结果表明，利用相元素分配量随温度变化的特征，便于揭示不同温度区间M23C6及MX相的稳定性，合理确定不同MX相的亚类型及M和X的构成及演化规律．此外，有助于了解基体相含碳量的变化对M23C6和MX相的影响．

英文摘要：

Chemical compositions and amounts of equilibrium phases in T/P91 heat resistant steel in the temperature range of 450--1200℃ were calculated using thermodynamic software ＇Thermo Calc＇ . Concept of elemental partitioning fraction was introduced to study the elemental partitioning characteristics of main alloying elements such as Cr, Mo, Fe, V, Nb, C and N, the stability, the constituents and the evolutional rule of the equilibrium phases at elevated temperatures. The results show that using the elemental partitioning characteristics with the change of temperatures the stability of the equilibrium phases can be easily revealed, and the sub-types of MX and the formation of M and X in MX as well as the elemental evolution rule in MX type phases can be reasonably determined. And the effect of carbon content in the matrix phase on the formation of MX phases can be helpfully understood.