In reactor pressure vessel materials, the formation of Mn- and Ni-rich nanoclusters is a major cause of neutron irradiation embrittlement. The segregation of these solute atoms into dislocation loops has attracted attention as a mechanism to accelerate solute clustering. In this study, the behaviors of solute Mn and Ni atoms in Fe-0.6wt.%Ni, Fe-1.4wt.%Mn, and Fe-1.4wt.%Mn-0.6wt.%Ni alloys irradiated at 400 °C up to 3 dpa were analyzed using three-dimensional atom probe tomography. Solute atom clusters were observed in all materials, and their shapes were spherical, flat, and torus in FeNi, FeMn, and FeMnNi, respectively. In ternary alloy FeMnNi, Mn and Ni atoms were concentrated in the sample in the form of arcs, and the orientation of the plane containing the arcs was estimated by comparing field desorption images. The size, number density, and orientation of this structure were found to be in good agreement with those of both types of dislocation loops, namely, = 1/2 〈111〉 and = 〈100〉, identified in a previous study using the same material. The positions of Ni and Mn enrichment did not fully overlap. Ni atoms tended to be concentrated more in the inner part of the loop than the Mn atoms. Mn atoms were enriched only in the vicinity of the dislocation loops, whereas Ni atoms showed a higher concentration inside the dislocation loops than in the bulk.

中文翻译：

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400 °C 2.8 MeV Fe 离子辐照下铁基合金中溶质锰和镍原子与位错环的相互作用

在反应堆压力容器材料中，富锰和富镍纳米团簇的形成是中子辐照脆化的主要原因。这些溶质原子偏析成位错环作为加速溶质聚集的机制引起了人们的关注。在本研究中，Fe-0.6wt.%Ni、Fe-1.4wt.%Mn 和 Fe-1.4wt.%Mn-0.6wt.%Ni 合金中固溶 Mn 和 Ni 原子在 400 °C 辐照下的行为使用三维原子探针断层扫描对 3 dpa 进行了分析。在所有材料中均观察到溶质原子簇，其形状在 FeNi、FeMn 和 FeMnNi 中分别为球形、扁平形和圆环形。在三元合金 FeMnNi 中，Mn 和 Ni 原子以弧形形式集中在样品中，通过比较场解吸图像来估计包含弧形的平面的方向。发现该结构的尺寸、数密度和方向与两种类型的位错环（即 = 1/2 〈111〉 和 = 〈100〉 非常一致，在之前的研究中使用相同的方法确定）材料。 Ni、Mn富集位置不完全重叠。 Ni原子比Mn原子更倾向于集中在环的内部。 Mn 原子仅在位错环附近富集，而 Ni 原子在位错环内的浓度高于位错环内的浓度。