First-principles investigation on the composition of Ni-Si precipitates formed in irradiated stainless steels
First-principles investigation on the composition of Ni-Si precipitates formed in irradiated stainless steels
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辐照不锈钢中Ni-Si析出物成分的第一性原理研究
DOI：
10.1016/j.jnucmat.2017.07.029
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发表时间：
2017
影响因子：
3.1
通讯作者：
N. Sekimura
中科院分区：
文献类型：
--
作者：
Dongyue Chen;Kenta Murakami;K. Dohi;K. Nishida;Toshiharu Ohnuma;N. Soneda;Zhengcao Li;Li Liu;N. Sekimura
最近的原子探针层析成像（APT）研究揭示了辐照不锈钢中Ni-Si沉淀物的复杂性质。透射电子显微镜（TEM）证实了Ni 3Si γ′相的存在，但APT测得的析出相Ni/Si比小于其理论值3。通过考虑Ni 3Si γ′相中的晶格缺陷，对APT结果进行了解释。使用第一性原理计算，在Ni位点上的Si取代被发现是这里考虑的所有单个缺陷中最稳定的。虽然两个这样的替代缺陷彼此排斥，但排斥力随着它们的分离距离的增加而迅速减小。通过保持足够大的间距，可以在γ′相中以高密度出现多个Si替代，这可能是APT观察到的Ni-Si沉淀中Ni/Si原子比小的重要原因之一。
Recent atom probe tomography (APT) study has revealed the complicated nature of Ni-Si precipitates in irradiated stainless steels. Although Ni3Si γ′ phase has been confirmed under transmission electron microscopy (TEM), the Ni/Si ratio of the precipitates detected by APT is smaller than its theoretical value 3. An interpretation of the APT results is provided in this work by considering the lattice defects in the Ni3Si γ′ phase. Using first principles calculations, Si substitutions on Ni sites were found to be the most thermodynamically stable among all the single defects considered here. Although two such substitutional defects are repulsive to each other, the repulsion decreases quickly as their separation distance grows. By keeping a large enough distance between each other, multiple Si substitutions can appear at high densities in the γ′ phase, which can be one important contributor to the small Ni/Si atom ratio in Ni-Si precipitates observed by APT.
影响因子：
9.4
作者：
Udagawa, Yutaka;Yamaguchi, Masatake;Fuketa, Toyoshi
通讯作者：
Fuketa, Toyoshi