Formation of Ni-Si clusters and their relationship with dislocation loops in irradiated stainless steels
Formation of Ni-Si clusters and their relationship with dislocation loops in irradiated stainless steels
复制标题
辐照不锈钢中 Ni-Si 团簇的形成及其与位错环的关系
DOI：
10.1016/j.jnucmat.2023.154366
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发表时间：
2023
影响因子：
3.1
通讯作者：
Sekimura Naoto
中科院分区：
文献类型：
--
作者：
Chen Dongyue;Murakami Kenta;Dohi Kenji;Nishida Kenji;Chen Liang;Li Zhengcao;Sekimura Naoto
Ni-Si团簇是辐照不锈钢辐照硬化的主要贡献者。Ni-Si团簇的异质形核与辐照诱导的凹陷偏析(如位错环)有关，在位错环上可能形成的Ni-Si团簇可能影响这两类缺陷的演化过程。此外，Ni-Si团簇的性质尚不清楚，这反映在已报道的团簇组成上的差异。在本研究中，不同硅含量的316L不锈钢模型合金在450℃下被5dpa辐照，用原子探针层析技术对Ni-Si团簇进行了分析，并与透射电子显微镜观察到的回路进行了比较。结果表明，较高的Si含量提高了团簇的数密度和大小，但不改变团簇的组成。发现了不连续的环状、连续的环状和盘状的星团。团簇的形状、大小和晶体取向支持在Frank环和完美环上形成环状团簇。在大的环状团簇中，Si和Ni分别集中在环状团簇的外部和内部区域，这可能与形成环状团簇的间隙型Frank环的应力场有关。较大的Ni-Si团簇的恒定组成表明可能存在择优的Ni-Si相。结合一维浓度分布和使用硅原子和镍原子的MSM的结果，大团簇的Ni/Si比在1.6-3.0之间。
Ni–Si cluster is a major contributor to the irradiation hardening in irradiated stainless steels. The heterogeneous nucleation of Ni–Si clusters is associated with radiation-induced segregation at sinks (e.g., dislocation loops), and the possible formation of Ni–Si clusters on dislocation loops may influence the evolution process of the two types of defects. Besides, the nature of Ni–Si clusters is unclear yet, reflected by the discrepancies in the reported cluster composition. In this study, model alloys of 316L stainless steel with different Si contents were irradiated to 5 dpa at 450°C. Ni–Si clusters were analyzed by atom probe tomography and were compared with the loops observed by transmission electron microscopy. Results showed that higher Si content promoted cluster number density and size but did not change cluster composition. Discontinuous torus-shaped, continuous torus-shaped, and disk-shaped clusters were discovered. The cluster shape, size, and crystallographic orientation supported the formation of torus-shaped clusters on Frank loops and perfect loops. In large torus-shaped clusters, Si and Ni tended to concentrate in the outer and inner regions of the torus, respectively, and it may be attributed to the stress field of the interstitial-type Frank loops on which the torus-shaped clusters were formed. The constant composition of large Ni–Si clusters indicated the possible existence of a preferential Ni–Si phase. Combining the results of the 1D concentration profile and the MSM using Si atoms and Ni atoms, the Ni/Si ratio of the large clusters was between 1.6–3.0.