An understanding of the thermodynamic and phase diagram data for the C–Nb–Ti system is essential for the development of cermets, cemented carbides as well as Nb-based superalloys. Based on a critical evaluation of the literature data, the C–Nb–Ti ternary system has been reviewed and assessed by means of the CALPHAD technique. A self-consistent thermodynamic description for the C–Nb–Ti system has been developed over the whole composition and temperature ranges. Comprehensive comparisons between the calculated and measured phase diagrams available in the literature show that the reliable experimental information can be satisfactorily accounted for by the present thermodynamic description. The as-cast microstructures of several Nb-based superalloys reported in the literature have been analyzed by using Scheil solidification simulations based on the presently obtained thermodynamic database. The improvement mechanism of room-temperature hardness and high-temperature yield stress can be successfully interpreted according to the simulated amount of (Nb,Ti)C carbide, the effective strengthening particles in the as-cast Nb-based superalloys, which indicates a powerful tool of thermodynamic calculations in materials development.

对C–Nb–Ti系统的热力学和相图数据的了解对于金属陶瓷，硬质合金以及Nb基高温合金的开发至关重要。在对文献数据进行严格评估的基础上，已通过CALPHAD技术对C–Nb–Ti三元系统进行了评估。在整个成分和温度范围内，已经开发出了C-Nb-Ti系统的自洽热力学描述。文献中提供的计算相图和实测相图之间的全面比较表明，本热力学描述可以令人满意地说明可靠的实验信息。文献中报道的几种基于Nb的高温合金的铸态组织已经通过基于目前获得的热力学数据库的Scheil凝固模拟进行了分析。根据模拟量的Nb基高温合金中有效强化颗粒（Nb，Ti）C碳化物的模拟量，可以成功地解释室温硬度和高温屈服应力的改善机理。材料开发中热力学计算的工具。