在高熵合金中添加适量的Al，Cu原子可以显著提升合金的力学性能，但是关于Al，Cu原子对高熵合金耐腐蚀性能的研究报道较少。为揭示Al，Cu原子对高熵合金腐蚀行为的影响规律，本工作以具有优异力学性能的FeCoNi基中熵合金为研究对象，通过高熵合金成分设计经验公式设计了FCC单相Fe₂₅Co₂₅Ni₂₅Al₁₀Cu₁₅（Al10Cu15）合金以及BCC+FCC双相Fe₂₅Co₂₅Ni₂₅Al₁₅Cu₁₀（Al15Cu10）和Fe₂₅Co₂₅Ni₂₅Al₂₀Cu₅（Al20Cu5）合金。XRD物相分析表明，随着Al含量的增加，FCC相占比逐渐降低，BCC占比逐渐提高，与理论计算结果一致。SEM微观组织和EDS分析表明，增加Al的添加量，减少Cu的添加量，晶粒的形貌由树枝晶（Al10Cu15，Al15Cu10）转变为等轴晶（Al20Cu5），枝晶间相的成分也会发生显著变化。Al10Cu15枝晶间的组织为富Cu的FCC相，Al15Cu10枝晶间的组织为富Al，Ni，Cu的BCC相，Al20Cu5晶界的组织为富Fe，Co的FCC相。动电位极化 （potentiodynamic polarization， PDP） 实验表明，Al含量较高的合金为两相结构，在长周期浸泡过程中容易发生电偶腐蚀，钝化膜的完整性易遭到破坏，导致合金的耐腐蚀性较差。电化学阻抗谱（electrochemical impedance spectroscopy， EIS）测试表明，随着浸泡时间的延长，Al添加量较高的合金反应电阻会出现显著的下降，与PDP分析结果一致。室温静态浸泡实验表明，与Al10Cu15合金相比，Al15Cu10与Al20Cu5合金在长时间的浸泡下，更容易发生电偶腐蚀。由此可得，过量添加Al原子诱发的第二相，会显著恶化材料的耐腐蚀性能。保证合金组织成分的均匀性，是提升材料耐腐蚀性能的有效手段。

Adding appropriate amounts of Al and Cu atoms to high-entropy alloys （HEAs） can significantly improve mechanical properties of the alloys， but there are few research reports on the corrosion resistance of Al and Cu atoms in HEAs. To reveal the influence of Al and Cu atoms on the corrosion behavior of HEAs， this study focuses on FeCoNi based medium entropy alloys with excellent mechanical properties. FCC single-phase Fe₂₅Co₂₅Ni₂₅Al₁₀Cu₁₅（Al10Cu15） alloy and BCC+FCC dual-phase Fe₂₅Co₂₅Ni₂₅Al₁₅Cu₁₀（Al15Cu10） and Fe₂₅Co₂₅Ni₂₅Al₂₀Cu₅（Al20Cu5） alloys are designed using empirical formulas for high-entropy alloy composition design. XRD analysis shows that the amount of FCC phase decreases and the amount of BCC increases with the increase of Al content， which is consistent with the theoretical calculation. SEM microstructure and EDS analysis show that increasing the amount of Al added and decreasing the amount of Cu added result in a transformation of the grain morphology from dendritic （Al10Cu15， Al15Cu10） to equiaxed （Al20Cu5）， and the composition of the interdendritic also changes significantly. The Al10Cu15 interdendritic microstructure is a Cu-rich FCC phase， the Al15Cu10 interdendritic microstructure is an Al-， Ni- and Cu-rich BCC phase， and the Al20Cu5 grain boundaries microstructure is a Fe- and Co-rich FCC phase. The potentiodynamic polarization（PDP） experiments show that alloys with high Al content have a dual-phase structure and are prone to galvanic corrosion during long-term immersion. The integrity of the passivation film is easily damaged， resulting in poor corrosion resistance of the alloy. The electrochemical impedance spectroscopy （EIS） tests show that the reaction resistance of alloys with higher Al additions decreases significantly with the prolongation of immersion time， which is consistent with the results of PDP analysis. Static immersion experiments at room temperature show that compared with Al10Cu15 alloy， Al15Cu10 and Al20Cu5 alloys are more susceptible to galvanic corrosion under prolonged immersion. It can be concluded that the addition of an excessive amount of Al atoms induced by the second phase significantly deteriorates the corrosion resistance of the material. Ensuring the homogeneity of alloy structure composition is an effective means to improve the corrosion resistance of materials.