The emergence of eutectic high-entropy alloys (EHEAs) offers new insights into the design of next generation structural alloys, which is due to their stable dual-phase microstructure and outstanding mechanical properties from room to elevated temperatures. In this work, a series of (CoFe₂NiV_0.5Mo_0.2)_100−xNb_x (0 ≤ x ≤ 12) EHEAs were designed and prepared via vacuum arc-melting. Typical eutectic microstructure composing lamellar face-centered cubic solid solution phase and C14 Laves phase appears in the as-cast EHEA when x = 9. The microstructure turns to hypoeutectic or hypereutectic when x is below or beyond that critical value accordingly. The volume fraction of the hard Laves phase is proportional to the Nb addition, leading to the strength increment yet at the expense of ductility at room temperature. In particular, the EHEA having 4 at% Nb shows a compressive strength of 2.1 GPa with an elongation to fracture of 45%, while EHEAs containing 9 and 10 at% Nb exhibit ultrahigh yield strengths of over 1.4 GPa. The effect of Nb addition on the corrosion resistance of this Cr-free EHEA system was also studied. The EHEA containing 9 at% Nb has the best anti-corrosion performance in the 3.5 wt% NaCl solution at 298 ± 1 K, indicating a good combination of mechanical and corrosion properties.

中文翻译：

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新型（CoFe 2 NiV 0.5 Mo 0.2）100-x Nb x共晶高熵合金，具有优异的机械和腐蚀性能组合

共晶高熵合金（EHEAs）的出现为下一代结构合金的设计提供了新的见识，这归因于它们稳定的双相微结构以及从室温到高温的出色机械性能。在这项工作中，一个系列（由CoFe ₂的NiV _0.5沫_0.2）_{100- X} Nb的_X（0≤  X  ≤12）EHEAs设计并通过真空电弧熔化制备。典型共晶组织构成的层状的面心立方固溶相和C14 Laves相出现在铸态EHEA当X  = 9的显微组织轮流亚共晶或过共晶时X相应地低于或超过该临界值。硬Laves相的体积分数与Nb的添加成正比，导致强度增加，但以室温下的延展性为代价。尤其是，具有4 at％Nb的EHEA表现出2.1 GPa的抗压强度，断裂伸长率为45％，而包含9和10 at％Nb的EHEA表现出超过1.4 GPa的超高屈服强度。还研究了添加Nb对这种无铬EHEA系统耐蚀性的影响。含有9 at％Nb的EHEA在3.5 wt％NaCl溶液中在298±1 K时具有最佳的耐腐蚀性能，表明机械性能和腐蚀性能完美结合。