High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe₂NiCrNb_x was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe₂NiCrNb_0.34; the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio.

高熵合金由于其独特而有趣的机械性能而引起了广泛的研究兴趣。共晶高熵合金作为高熵合金的一个类别，结合了共晶和高熵合金的优点，具有优良的力学性能和铸造性能。已经开发出一些共晶高熵合金并显示出令人兴奋的特性。本文基于共晶高熵合金的物理冶金学，设计了中熵合金Fe ₂ NiCrNb _x。铸态合金由FCC和Laves相组成，Nb元素促进初生Laves相的形成，合金的硬度随着Nb元素的增加而增加。四种合金中，共晶点的共晶化学成分为Fe₂镍铬铌_0.34；该合金具有良好的强度和塑性平衡。极限综合强度2267MPa，断裂应变30.8%。实验数据和分析确定了共晶点和优异的机械性能。此外，昂贵的 Co 元素被 Fe 元素取代。考虑到性价比，这种廉价的中熵合金具有广阔的前景。