Abstract The knowledge of phase diagram is theoretical principle for compositional design. Since Ti and Al are important alloying elements for Nb–Si alloys, and Nb and Si are important alloying elements for Ti–Al alloys, Nb–Ti–Si–Al phase equilibria is prerequisite for optimal microstructural design of both Nb–Si and Ti–Al systems. In this work, key alloys were selected firstly according to calculated isothermal section based on extrapolated thermodynamic description, then key alloy ingots were prepared by arc-melting and heat treated to reach equilibrium state. Currently obtained phase equilibria data coupled with critically reviewed literature data were employed to study the element interaction of relative phases (α-Nb5Si3, β-Nb5Si3, Ti5Si3, Nb3Al and TiAl et al.) in the Nb–Ti–Si–Al system. Thermodynamic parameters of these phases were modified accordingly to reproduce the determined phase relationships. Finally, the important phase equilibria features of the Nb–Ti–Si–Al system were described with several isothermal sections. The phase equilibria extending from ternary systems and new phase equilibria appearing in the quaternary space were demonstrated in this work.

中文翻译：

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Nb-Ti-Si-Al四元系富金属侧的相平衡和多元素相互作用研究

摘要 相图知识是组成设计的理论原理。由于 Ti 和 Al 是 Nb-Si 合金的重要合金元素，而 Nb 和 Si 是 Ti-Al 合金的重要合金元素，Nb-Ti-Si-Al 相平衡是优化 Nb-Si 和 Ti 显微组织设计的先决条件–铝系统。在这项工作中，首先根据基于外推热力学描述的计算等温截面选择关键合金，然后通过电弧熔化和热处理达到平衡状态制备关键合金锭。目前获得的相平衡数据与经过严格审查的文献数据相结合，用于研究 Nb-Ti-Si-Al 系统中相关相（α-Nb5Si3、β-Nb5Si3、Ti5Si3、Nb3Al 和 TiAl 等）的元素相互作用。相应地修改这些相的热力学参数以再现确定的相关系。最后，用几个等温截面描述了 Nb-Ti-Si-Al 系统的重要相平衡特征。这项工作证明了从三元系统延伸的相平衡和出现在四元空间中的新相平衡。