The high-entropy (HE) effect has been reported to be able to improve the structural stability of materials under irradiation. However, whether the HE strategy is also effective for MAX phases having specific metal-carbide intercalating structures and suffering from serious diffusional transformation under irradiation remains unknown. In this study, NbAlC and high-entropy (TiZrVNbTa)AlC were prepared and irradiated by 540 keV He ions with the fluence of 1 × 10 /cm. The structural evolution were characterized and compared in detail by transmission electron microscopes. Generation of anti-site defects and hex‑cubic diffusional transformation were both observed in NbAlC, whereas the latter was absent in (TiZrVNbTa)AlC. The larger formation energy of C-related trimer defects as-revealed by ab initio calculation, dispersed diffusion of atoms under non-uniform stress field, and more intrinsic Al vacancies with lower migration barrier are considered to be the main reasons for the enhanced irradiation resistance in (TiZrVNbTa)AlC.

中文翻译：

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He离子辐照下高熵(TiZrVNbTa)2AlC陶瓷的约束扩散转变

据报道，高熵（HE）效应能够提高材料在辐照下的结构稳定性。然而，HE 策略对于具有特定金属碳化物插层结构并在辐照下发生严重扩散转变的 MAX 相是否也有效仍然未知。本研究制备了NbAlC和高熵(TiZrVNbTa)AlC，并用540 keV He离子进行辐照，注量为1 × 10 /cm。通过透射电子显微镜对结构演化进行了详细表征和比较。NbAlC 中均观察到反位点缺陷的产生和六方扩散转变，而 (TiZrVNbTa)AlC 中则不存在后者。从头计算发现，C相关三聚体缺陷的较大形成能、非均匀应力场下原子的分散扩散以及更多具有较低迁移势垒的本征Al空位被认为是耐辐照性增强的主要原因(TiZrVNbTa)AlC。