The TiNbVTaCr ( = 0, 0.1, 0.2, 0.5) refractory high-entropy alloys (RHEAs) with an excellent combination of ductility and strength were designed and prepared for high-temperature applications. The yield strength, ultimate tensile strength, and elongation of the TiNbVTaCr alloy were 878 MPa, 928 MPa, and 21.6 %, respectively. Important issues of microstructure evolution, precipitation process, and their impact on mechanical properties were concerned. Then, the effect of Cr content on the mechanical properties of TiNbVTaCr alloys was evaluated through a quantitative analysis of the strengthening mechanism, which elucidated the trade-off relationship between solid solution strengthening and precipitation strengthening in RHEA. The microstructure evolution of the TiNbVTaCr alloys involved the formation and interconversion of titanium allotropes (α-Ti and β-Ti) and the precipitation of the Laves phase. Significant embrittlement was induced by the preferential precipitation of α-Ti on the grain boundary. The TiNbVTaCr alloys exhibited an incubation period for Laves phase precipitation, which was related to the Cr content in the alloy. The Laves phase preferentially nucleated next to α-Ti due to the redistribution of elements during the α-Ti precipitation process. The precipitation of the Laves phase played an important role in enhancing the strength of the TiNbVTaCr alloys.

中文翻译：

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TiNbV0.5Ta0.5Crx(x=0、0.1、0.2、0.5)难熔高熵合金的显微组织与力学性能


TiNbVTaCr (= 0, 0.1, 0.2, 0.5) 耐火高熵合金 (RHEA) 具有优异的延展性和强度，专为高温应用而设计和制备。 TiNbVTaCr合金的屈服强度、极限抗拉强度和延伸率分别为878 MPa、928 MPa和21.6%。人们关注微观结构演变、沉淀过程及其对力学性能的影响等重要问题。然后，通过强化机制的定量分析，评估了Cr含量对TiNbVTaCr合金力学性能的影响，阐明了RHEA中固溶强化和沉淀强化之间的权衡关系。 TiNbVTaCr 合金的微观结构演化涉及钛同素异形体（α-Ti 和 β-Ti）的形成和相互转化以及 Laves 相的析出。 α-Ti 在晶界上的优先析出引起了显着的脆化。 TiNbVTaCr合金表现出Laves相析出的孕育期，该孕育期与合金中Cr含量有关。由于 α-Ti 沉淀过程中元素的重新分布，Laves 相优先在 α-Ti 旁边成核。 Laves相的析出对于提高TiNbVTaCr合金的强度起到了重要作用。