【摘要】 综合评估了文献报道的Zr-Nb-O三元系及其子二元系的相图及热力学信息。液相的Gibbs自由能采用离子亚晶格模型描述,固溶体相(α,β)和所有化合物(αZrO2,βZrO2,γZrO2,NbO,NbO2和Nb2O5)的Gibbs自由能都采用双亚晶格模型描述。用CALPHAD(CALculation ofPHAse Diagrams)技术,使用Pandat软件中的PanOptimizer优化模块,对Zr-O二元系进行了热力学优化,计算得到的相图和热力学性质与实验结果相吻合。应用优化的Zr-O二元系模型参数,结合Zr-Nb、Nb-O已有的热力学评估结果,对Zr-Nb-O三元系进行了热力学优化,得到了该体系的一套热力学模型参数。计算了Zr-Nb-O三元系在1273,1473和1773 K温度下的等温截面,与实验数据符合得较好。计算了若干该体系在富Zr区α+ββ的相转变温度,结果和实验测量也能较好地吻合。研究结果对建立多元锆合金热力学数据库,以及指导新型锆基合金材料的成分设计具有重要意义。更多还原

【Abstract】 The experimental phase diagrams and thermodynamic data of the Zr-Nb-O ternary system and its sub-binary systems in the literature were reviewed.The liquid phase was described by the ionic sub-lattice model while solid solution phases(α,β) and all of the compounds(αZrO2,βZrO2,γZrO2,NbO,NbO2 and Nb2O5) were modeled using two sub-lattice model.The thermodynamic optimization of the Zr-O binary system was carried out using the PanOptimizer program in the Pandat software,with CALPHAD(CALculation of PHAse Diagrams) technique,and the calculated phase diagram and thermodynamic properties were in good agreement with the experimental data.Using the optimized parameters of the Zr-O system together with the results based on the previous thermodynamic assessments of the Zr-Nb and Nb-O systems,the thermodynamic optimization of the Zr-Nb-O ternary system was performed,and a set of thermodynamic parameters was obtained.The isothermal sections of the Zr-Nb-O ternary system at 1273,1473 and 1773 K and several α+ββ phase transition temperatures in the Zr-rich portion were calculated.All the calculated results were in good agreement with the experimental data.The results were helpful to the construction of the thermodynamic database for zirconium alloys,and might provide a significant guide for the alloy design of new type Zr based materials.更多还原