High-entropy alloys (HEAs) have been considered as a promising candidate for nuclear engineering due to their intriguing irradiation tolerance. The microstructure stabilities, including the radiation-induced precipitation (RIP), swelling, and segregation (RIS) in HEAs, are of great significance for applications. In this paper, the Fe₃₀Cr₂₅Ni₂₀Co₁₅Mn₁₀ HEA was irradiated by high-energy Au²⁺ ions with a peak dose of ∼ 70 displacements per atom (dpa). The formation of voids, nanoscale precipitation, segregation, and mechanical properties before and after irradiation was characterized carefully, using scanning/transmission electron microscopy (S/TEM), atom probe tomography (APT), and nanoindentation. The results indicate that the HEA presents a very low swelling rate of ∼ 0.002%/dpa. After irradiation, no nanoscale precipitation is observed, confirming the excellent stability of the HEA microstructure. The RIS is observed for the first time at nanotwin boundaries in the HEA after irradiation. The elements, Co and Ni, are enriched slightly, while Fe, Cr, and Mn depleted on the nanotwin boundaries after irradiation. The irradiation-induced segregation level is obviously suppressed in the HEA due to the sluggish atom diffusion. The hardness remains almost unchanged after irradiation. The nanotwin boundaries act as defect sinks to absorb irradiation-induced vacancies and interstitials, reducing the swelling rate and relieving hardening. The low swelling, weak RIS level, and almost no hardening after a high dose irradiation indicate that the Fe₃₀Cr₂₅Ni₂₀Co₁₅Mn₁₀ HEA possesses an outstanding irradiation tolerance.

高熵合金 (HEA) 由于其耐辐照性而被认为是核工程的有前途的候选材料。HEA 中的微观结构稳定性，包括辐射诱导析出 (RIP)、膨胀和偏析 (RIS)，对应用具有重要意义。本文采用高能 Au ²⁺辐照Fe ₃₀ Cr ₂₅ Ni ₂₀ Co ₁₅ Mn ₁₀ HEA离子的峰值剂量约为每原子 70 个位移 (dpa)。使用扫描/透射电子显微镜 (S/TEM)、原子探针断层扫描 (APT) 和纳米压痕仔细表征辐照前后空隙的形成、纳米级沉淀、偏析和机械性能。结果表明，HEA 的溶胀率非常低，约为 0.002%/dpa。辐照后，没有观察到纳米级沉淀，证实了 HEA 微观结构的优异稳定性。RIS 在辐照后首次在 HEA 的纳米孪晶边界处被观察到。元素 Co 和 Ni 略微富集，而 Fe、Cr 和 Mn 在辐照后在纳米孪晶边界上耗尽。由于缓慢的原子扩散，辐射诱导的偏析水平在 HEA 中明显受到抑制。辐照后硬度几乎保持不变。纳米孪晶边界作为缺陷汇吸收辐射引起的空位和间隙，降低膨胀率并缓解硬化。低膨胀、弱 RIS 水平和高剂量照射后几乎没有硬化表明 Fe₃₀ Cr ₂₅ Ni ₂₀ Co ₁₅ Mn ₁₀ HEA 具有出色的辐照耐受性。