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A new eutectic high-entropy alloy (EHEA) of Cr 41 CoFeNi was prepared by arc melting technique. The microstructure and corrosion resistance of the Cr 41 CoFeNi EHEA were systematically investigated by EBSD, TEM, EIS and XPS analyses. The results revealed that the Cr 41 CoFeNi EHEA showed a dual-phase structure consisting of BCC phase and FCC phase, and the morphologies displayed the lamellar eutectic and network-shaped eutectic. Compared with 316 L stainless steel, the Cr 41 CoFeNi EHEA exhibited a better anti-corrosion property in 0.5 M H 2 SO 4 solution. This was mainly attributed to the formation of a dense and stable Cr-oxide layer on the surface of Cr 41 CoFeNi EHEA, which retarded further dissolution of the matrix. Moreover, bound water could adsorb metal ions to form a new protective film, which played an important role in improving the corrosion resistance of the Cr 41 CoFeNi EHEA. However, the elemental segregation and chemical potential difference between phases increased the defects in the passive film and accelerated its pitting corrosion of low potential phase. Moreover, the (Co, Fe, and Ni)-enriched FCC structured phase was preferentially eroded. • A novel eutectic high-entropy alloy of Cr 41 CoFeNi(EHEA) was designed and fabricated • The corrosion mechanisms of EHEA and 316 L stainless steel(316 L SS) were clarified • The passive film thickness of EHEA was about 5.3 times greater than that of 316 L SS • The main constituents of passive film on EHEA were Cr-oxide and bound water [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs) have five or more principal elements with four core effects: high entropy, sluggish diffusion, severe lattice distortion, and cocktail effects. These effects lead to some distinct properties of HEAs. Some HEAs are promising for high temperature applications and have the potential to replace Ni-base superalloys as the next generation high-temperature materials, such as high entropy superalloys (HESAs) and refractory HEAs. The microstructures of HESAs consisting of γ and γ ′ phases are similar to that of Ni-base superalloys. Refractory HEAs contain refractory elements with high melting temperatures. Thus, a number of aspects of HESAs and refractory HEAs are reviewed and discussed in the present paper, including microstructure, density, room-temperature mechanical properties, high-temperature strength, creep behavior, and oxidation resistance. Furthermore, a number of future research topics are suggested, emphasizing on developing high-performance high-temperature materials. [ABSTRACT FROM AUTHOR]