反应堆压力容器材料中Ni界面偏析对富Cu溶质团簇演化影响的模拟研究

目的定量研究镍原子的界面偏析对降低团簇与基体间表面能及促进团簇形核、提升团簇数密度的贡献,以深化对反应堆压力容器溶质团簇演化过程和辐照脆化中溶质团簇机理的认识。方法通过考虑Fe-Cu-Ni三元合金溶质团簇中镍原子的界面偏析,利用团簇动力学方法研究了团簇中镍原子分布对富铜溶质团簇演化的影响。结果相比铜团簇,加入镍原子后的铜镍团簇自由能显著降低,团簇数密度显著提高;随团簇中镍原子界面偏析加剧,团簇自由能与团簇尺寸逐渐下降,团簇数密度先小幅上升,后下降。结论镍可以促进富铜溶质团簇的形核,提升团簇的数密度,而其中镍原子的界面偏析对促进团簇形核的贡献可能有限;在团簇生长过程中,镍原子的界面偏析可能会抑制其生长,减小团簇的尺寸。

Simulation Study on the Influence of Ni Interface Segregation on the Evolution of Cu-rich Solute Clusters in Reactor Pressure Vessel Materials

This paper aims to quantitatively study the contribution of the interface segregation of nickel atoms to the reduction of the surface energy between the clusters and the matrix, the promotion of cluster nucleation, and the increase of cluster number density, in order to deepen the understanding of the evolution of solute clusters in the reactor pressure vessel and the solute clusters mechanism in the irradiation embrittlement. By considering the interface segregation of nickel atoms in solute clusters of Fe-Cu-Ni ternary alloy, cluster dynamics method was used to study the influence of the distribution of nickel atoms in the clusters on the evolution of copper-rich solute clusters. Compared with copper clusters, the free energy of copper-nickel clusters after adding nickel atoms significantly reduced, and cluster number density significantly increased; as the interface segregation of nickel atoms in the clusters intensifies, the free energy of cluster and the cluster size gradually decreased, and cluster number density first rose slightly and then dropped. Nickel can promote the nucleation of copper-rich solute clusters and increase cluster number density. Among them, the interface segregation of nickel atoms may have limited contribution to promoting cluster nucleation; during the cluster growth process, the interface segregation of nickel atoms may be inhibit its growth and reduce the cluster size.