Molecular dynamic simulations evaluating the effect of the stacking fault energy on defect formations in face-centered cubic metals subjected to high-energy particle irradiation
Molecular dynamic simulations evaluating the effect of the stacking fault energy on defect formations in face-centered cubic metals subjected to high-energy particle irradiation
复制标题
DOI：
10.1016/j.commatsci.2021.110479
复制
发表时间：
2021-07
影响因子：
3.3
通讯作者：
S. Terayama;Yuuki Iwase;Sho Hayakawa;T. Okita;M. Itakura;Katsuyuki Suzuki
中科院分区：
文献类型：
--
作者：
S. Terayama;Yuuki Iwase;Sho Hayakawa;T. Okita;M. Itakura;Katsuyuki Suzuki
奥氏体不锈钢作为轻水反应堆堆芯结构材料，具有面心立方（FCC）金属中极低的层错能（SFE）。为了评价超临界流体对高能粒子辐照下缺陷形成的影响，采用600 K时不同超临界流体作用下面心立方金属原子间相互作用势集和100 keV的初始撞击原子能（EPKA）进行了分子动力学模拟.结果表明，残余缺陷的数量与超临界流体萃取无关。然而，自填隙原子（SIA）团簇的特性确实依赖于SFE。对于小于一定尺寸的团簇，随着SFE的增加，滑动SIA团簇的比例减小，这与在低EPKA下观察到的趋势相似。然而，对于较大的集群，这只能在一个高EPKA检测到，滑动集群的比例增加。这些结果对应于静态能量计算，其中小团簇的Frank环和完美环之间的形成能差（ΔEF-P）随着SFE的增加而减小。相反，对于较大的团簇，由于稳定的完美环的形状限制，Δ EF-P的SFE依赖性发生变化。在600 K的高温下，在EPKA= 100 keV时可以检测到具有堆垛层错的大空位团簇，从而在较低的SFE下增强了这些团簇的形成。此外，这些集群中的几个类似于完美的环，边缘分裂成两个部分位错与堆垛层错，虽然在低EPKA检测到的最大的集群类似于堆垛层错四面体。
Austenitic stainless steels, which are used as incore structural materials in light water reactors, are characterized by an extremely low stacking fault energy (SFE) among face-centered cubic (FCC) metals. To evaluate the effects of SFE on defect formation under high-energy particle irradiation, molecular dynamics simulations were performed using the interatomic potential sets for FCC metals with different SFEs and a primary knock-on atom energy (EPKA) of 100 keV at 600 K. The results show that the number of residual defects is independent of the SFE. However, the characteristics of self-interstitial atom (SIA) clusters do depend on the SFE. For clusters smaller than a certain size, the ratio of glissile SIA clusters decreases as the SFE increases, which is similar to the trend observed at the low EPKA. However, for larger clusters, which can be detected only at a high EPKA, the ratio of glissile clusters increases. These results correspond to static energy calculations, in which the difference in the formation energy between a Frank loop and perfect loop (ΔEF-P) for the small clusters decreases as the SFE increases. In contrast, for the larger clusters, the SFE dependence of ΔEF-Pchanges due to the shape restrictions of stable perfect loops. At a high temperature of 600 K, large vacancy clusters with stacking faults can be detected at EPKA= 100 keV, resulting in the enhanced formation of these clusters at lower SFEs. Furthermore, several of these clusters were similar to perfect loops, with the edges split into two partial dislocations with stacking faults, although the largest clusters detected at low EPKAs were similar to stacking fault tetrahedrons.