Phase equilibria in the Al-Nb-V system are important data for the design of innovative Al-containing refractory-high-entropy alloys, however issues still open in this system. In the present work, Al-Nb-V phase equilibria at 1200 °C were re-investigated via microstructural characterization of heat-treated alloys using scanning electron microscopy, x-ray spectroscopy (EDS) and x-ray diffractometry. Results confirmed the existence of the three-phase fields BCC + Nb 3 Al + Nb 2 Al and BCC + Nb 2 Al + NbAl 3 and the absence of ternary compounds. The solubility of binary phases Nb 3 Al and Nb 2 Al into the ternary and the stability region of the BCC solid solution were improved while the solubility of Nb in V 5 Al 8 was confirmed negligible. In addition, VAl 3 + NbAl 3 diffusion couple were produced, confirming the miscibility gap between these phases and indicating the existence of NbAl 3 + VAl 3 + BCC equilibrium instead of NbAl 3 + VAl 3 + V 5 Al 8 .

中文翻译：

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Al-Nb-V 体系中 1200 °C 相平衡的实验研究

Al-Nb-V 系统中的相平衡是设计创新的含铝难熔高熵合金的重要数据，但该系统中的问题仍然存在。在目前的工作中，通过使用扫描电子显微镜、X 射线光谱 (EDS) 和 X 射线衍射对热处理合金进行微观结构表征，重新研究了 1200 °C 下的 Al-Nb-V 相平衡。结果证实了三相场BCC + Nb 3 Al + Nb 2 Al 和BCC + Nb 2 Al + NbAl 3 的存在，并且不存在三元化合物。二元相Nb 3 Al 和Nb 2 Al 在三元中的溶解度和BCC 固溶体的稳定区域得到改善，而Nb 在V 5 Al 8 中的溶解度被证实可以忽略不计。此外，还产生了 VAL 3 + NbAl 3 扩散偶，