The deformation behavior of VCoNi medium-entropy alloy at the temperatures ranging from 77 K to 573 K was experimentally investigated in this study. It showed that the high-density nanosized dislocation substructures and deformation twins played a major role in the tensile deformation at 77 K, and their synergistic effects caused an excellent combination of strength and ductility. When the temperature is higher than 473 K, the stress-strain curve exhibited obvious a clear serrated flow behavior but maintained good uniform elongation. The microstructure analysis indicated that a dynamically precipitated V-rich phase had an apparent influence on the deformation behavior above 473 K. Present results suggested that although the VCoNi alloy exhibited excellent mechanical properties in the present temperature range, the decreased FCC stability should be noticed, which could result in some changes of mechanical properties particularly at higher temperatures.

通过实验研究了VCoNi中熵合金在77 K至573 K温度范围内的变形行为。结果表明，高密度的纳米级位错亚结构和形变孪晶在77 K下的拉伸变形中起主要作用，它们的协同作用引起强度和延展性的良好结合。当温度高于473 K时，应力-应变曲线显示出明显的锯齿状流动特性，但保持了良好的均匀伸长率。显微组织分析表明，动态沉淀的富V相对473 K以上的变形行为有明显影响。目前的结果表明，尽管VCoNi合金在当前温度范围内表现出优异的机械性能，