FeCrMnxAlCu (x = 2.0, 1.5, 1.0, 0.5, and 0.0) high-entropy alloys (HEAs) were prepared using vacuum arc melting. The phase structure, microstructure, and element distribution of FeCrMnxAlCu (x = 2.0, 1.5, 1.0, 0.5, and 0.0) HEAs were analyzed using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The corrosion resistance of the alloy in a NaOH solution was evaluated using a potentiodynamic polarization curve, electrochemical impedance spectroscopy, an immersion test, WLI, and X-ray photoelectron spectroscopy. The results showed that FeCrMnxAlCu HEAs are an FCC+BCC bi-phase mixed structure with typical dendrite and interdendrite structures. The corrosion test demonstrated that the HEAs presented a breakthrough characteristic of activation–passivation–passivation. With an increase in Mn content, the corrosion potential shifted first positively and then negatively, and the corrosion current first decreased and then increased. Among HEAs, the FeCrMn0.5AlCu HEA had the best electrochemical corrosion resistance. After corrosion, both oxide and hydroxide corrosion product films were formed on the surface, which reduced the ion diffusion rate, slowed down the corrosion process, and improved the corrosion resistance.

中文翻译：

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FeCrMnxAlCu 高熵合金在 NaOH 溶液中的腐蚀行为

采用真空电弧熔炼制备 FeCrMnxAlCu (x = 2.0、1.5、1.0、0.5 和 0.0) 高熵合金 (HEA)。使用 X 射线衍射、扫描电子显微镜和能谱分析了 FeCrMnxAlCu (x = 2.0、1.5、1.0、0.5 和 0.0) HEA 的相结构、微观结构和元素分布。采用动电位极化曲线、电化学阻抗谱、浸泡试验、WLI和X射线光电子能谱评价合金在NaOH溶液中的耐腐蚀性能。结果表明，FeCrMnxAlCu HEA 为 FCC+BCC 双相混合结构，具有典型的枝晶和枝晶间结构。腐蚀测试表明，HEA呈现出突破性的活化-钝化-钝化特性。随着Mn含量的增加，腐蚀电位先正移后负移，腐蚀电流先减小后增大。在HEA中，FeCrMn0.5AlCu HEA具有最好的耐电化学腐蚀性能。腐蚀后，表面同时形成氧化物和氢氧化物腐蚀产物膜，降低了离子扩散速率，减缓了腐蚀过程，提高了耐腐蚀性能。