Fe-Ni-Si三元合金辐照诱发的Ni-Si团簇形核及生长演变机制

Nucleation and Growth of Irradiation-Induced Ni-Si Clusters in Fe-Ni-Si Ternary Alloy

目的探索辐照条件下Ni与Si元素的相互作用对RPV合金中团簇形成演变的影响。方法对PRV合金的三元模型合金Fe-Ni-Si做离子辐照实验,并采用原子探针技术对团簇进行分析,采用纳米压痕技术进行硬度分析。结果纳米压痕的结果表明,材料的硬度随辐照剂量的升高而增大。原子探针结果表明,辐照后材料中产生了Ni-Si溶质团簇,且随着辐照剂量的增加,团簇的数量密度与体积分数都呈现增大趋势。在不同的辐照剂量下,团簇中的Si/Ni不同,随着团簇尺寸的增大,Si/Ni比呈现上升趋势。结论在低剂量时,Ni-Si团簇处于早期独立形核阶段,团簇内的Ni占比较高;高剂量时,Ni-Si团簇的合并生长占主导地位,且主要以大团簇吞并小团簇的方式生长;团簇中Si的质量分数随着团簇的尺寸增加而增大。

In order to investigate the effects of interaction between Ni and Si on formation and evolution of clusters in RPV alloy,ion-irradiated experiments were carried out on Fe Ni Si ternary model alloy of PRV steel.The clusters were analyzed by using atom probe tomography(APT)and the hardness was analyzed by nano-indentation technology.The nano-indentation results indicated that the hardness of the samples increased with increasing in the irradiation dose.The atom probe results indicated that irradiation introduced formation of Ni-Si solute clusters in the alloy.The number density and volume fraction of the solute clusters increased with increasing dose.The Si/Ni ratio of the clusters are different under different irradiation doses.With the increase of cluster size,the Si/Ni ratio shows an upward trend.In conclusion,at the low dose,the Ni-Si clusters are in their early stage formation with a high Ni concentration;at the high dose,the growth of Ni-Si clusters is predominant,and mainly via large clusters merging with small clusters.Furthermore,the mass fraction of Si in clusters increases with the increase of cluster size.