反应堆压力容器钢辐照损伤缺陷之一的MnNiSi团簇的形成机制至今还没有一个统一明确的理论，但实验中发现，Ni对MnNiSi团簇的形核有明显影响。为探究Ni团簇在反应堆压力容器钢中MnNiSi团簇形成机制中的作用，本工作采用第一性原理模拟方法，利用VASP软件分别计算密排堆积型Ni₃团簇和平面型Ni₄团簇作为团簇形核核心时，在不同捕获位点对溶质原子、空位或哑铃(dumbbell)的捕获能力，并计算其形核路线发展趋势。结果表明，Ni₃团簇和Ni₄团簇均可作为MnNiSi团簇形核核心。Ni₃团簇可捕获Si原子和空位，Ni₄团簇可捕获Mn原子、Si原子和空位。在仅考虑捕获粒子是溶质原子时，Ni₃团簇可形核长大成γ₂相局部相结构，Ni₄团簇可形核长大成G相局部相结构。如果考虑哑铃和空位的作用，Ni₄团簇可形核长大成包含G相局部相等的多种相结构。

No unified and definitive theory exists regarding the formation mechanism of MnNiSi clusters, a type of irradiation damage defect in reactor pressure vessel (RPV) steel. However, experiments have shown that Ni has a substantial impact on the nucleation of these clusters. Thus, to investigate the role of Ni clusters in the formation mechanism of MnNiSi clusters in RPV steels, this study employed first-principles simulations using VASP software. The simulations calculated the capture ability of close-packed Ni₃ and planar Ni₄ clusters, acting as nucleation cores, toward solute atoms, vacancies, or dumbbells. The nucleation pathways following their combination were also calculated. The results indicated that both Ni₃ and Ni₄ clusters could serve as nucleation cores for MnNiSi clusters. The Ni₃ cluster could stably bind with a Si atom or a vacancy, whereas the Ni₄ cluster could stably bind with a Mn atom, a Si atom, or a vacancy. Specifically, when considering only solute atom capture, the nucleation pathway of the Ni₃ cluster could grow into part of the γ₂ phase structure, whereas that of the Ni₄ cluster could grow into part of the G phase structure. When incorporating dumbbell and vacancy interactions, the Ni₄ cluster could nucleate and grow into multiple distinct phase structures, including the G phase.