Wei Jiake, Feng Bin, Tochigi Eita, Shibata Naoya, Ikuhara Yuichi
Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-8656, Japan.
Center for Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto, 606-8501, Japan.
Nat Commun. 2022 Mar 18;13(1):1455. doi: 10.1038/s41467-022-29162-2.
Grain boundaries (GBs) are considered as the effective sinks for point defects, which improve the radiation resistance of materials. However, the fundamental mechanisms of how the GBs absorb and annihilate point defects under irradiation are still not well understood at atomic scale. With the aid of the atomic resolution scanning transmission electron microscope, we experimentally investigate the atomistic mechanism of point defects absorption by a ∑31 GB in α-AlO under high energy electron beam irradiation. It is shown that a disconnection pair is formed, during which all the Al atomic columns are tracked. We demonstrate that the formation of the disconnection pair is proceeded with disappearing of atomic columns in the GB core, which suggests that the GB absorbs vacancies. Such point defect absorption is attributed to the nucleation and climb motion of disconnections. These experimental results provide an atomistic understanding of how GBs improve the radiation resistance of materials.
晶界（GBs）被认为是点缺陷的有效汇，这提高了材料的抗辐射能力。然而，在原子尺度上，关于晶界在辐照下如何吸收和湮灭点缺陷的基本机制仍未得到很好的理解。借助原子分辨率扫描透射电子显微镜，我们通过实验研究了高能电子束辐照下α-AlO中一个∑31晶界吸收点缺陷的原子机制。结果表明，形成了一个位错对，在此过程中追踪了所有的铝原子列。我们证明，位错对的形成伴随着晶界核心中原子列的消失，这表明晶界吸收空位。这种点缺陷吸收归因于位错的形核和攀移运动。这些实验结果提供了关于晶界如何提高材料抗辐射能力的原子层面的理解。
