Multi-principal element alloys (MPEAs) demonstrate significant promise as structural materials for nuclear energy equipment owing to their exceptional mechanical properties and radiation-resistant performances. In these alloys, the grain boundary (GB) serves as a crucial microstructure that typically mitigates irradiation damage by absorbing the irradiation-induced defect. However, the micromechanisms governing the anti-irradiation performance of GBs in MPEAs remain unclear. In this study, we investigate the irradiation defect production during collision cascade in the model NiCoCr bicrystal system through atomic simulations, aiming to unveil the atomic-scale origin of GB to resist irradiation damage in MPEAs. The results reveal that GBs effectively serve as sinks for irradiation defects in NiCoCr. The sink efficiency depends on the GB energetic state, including GB excess energy and defect segregation energy, as well as the energetic difference between interstitial and vacancy segregation. Statistical analysis identifies a universally exponent function between the defect absorption rate at GB and GB energetic state. In NiCoCr, the GB-disorder-induced-entropy increase leads to a biased reduction in interstitial segregation energy, narrowing the gap between interstitial and vacancy segregation energies by approximately 11 % compared to Ni. This improvement enhances the overall resistance of GBs to irradiation damage. Additionally, preferential segregation of Ni interstitial atoms is notably enhanced in NiCoCr, contributing to a high defect absorption rate at GBs. This study provides new insights into the resistance of GBs to irradiation defects in MPEAs and suggests GB engineering as an effective strategy for developing advanced alloys with enhanced radiation tolerance.

中文翻译：

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揭示 NiCoCr 多主元合金晶界抗辐照损伤的起源

多主元合金（MPEA）由于其优异的机械性能和抗辐射性能，作为核能设备的结构材料展现出巨大的前景。在这些合金中，晶界 (GB) 是一种关键的微观结构，通常通过吸收辐照引起的缺陷来减轻辐照损伤。然而，MPEA 中 GB 抗辐照性能的微观机制仍不清楚。在这项研究中，我们通过原子模拟研究了模型NiCoCr双晶系统中碰撞级联过程中辐照缺陷的产生，旨在揭示GB在MPEA中抵抗辐照损伤的原子尺度起源。结果表明，晶界有效地充当了 NiCoCr 中辐照缺陷的汇。汇效率取决于晶界能量状态，包括晶界过剩能量和缺陷偏析能量，以及间隙和空位偏析之间的能量差。统计分析确定了 GB 缺陷吸收率和 GB 能量状态之间的通用指数函数。在 NiCoCr 中，晶界无序引起的熵增加导致间隙偏析能偏低，与 Ni 相比，间隙偏析能和空位偏析能之间的差距缩小了约 11%。这一改进增强了GB对辐照损伤的整体抵抗力。此外，NiCoCr 中 Ni 间隙原子的优先偏析显着增强，有助于 GB 处的高缺陷吸收率。这项研究为 MPEA 中 GB 的抗辐照缺陷提供了新的见解，并建议 GB 工程作为开发具有增强辐射耐受性的先进合金的有效策略。