Study of Near-Neighbor Structure of Point Defects in α-FE by Displacement Cascade
Study of Near-Neighbor Structure of Point Defects in α-FE by Displacement Cascade
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DOI：
10.1142/s0217979212501147
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发表时间：
2012-07
影响因子：
1.7
通讯作者：
Wei-Lu Wang;Wei Liu;Xuebang Wu;Q. Fang;Liu Changsong;Qun Huang;Yucheng Wu
中科院分区：
文献类型：
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作者：
Wei-Lu Wang;Wei Liu;Xuebang Wu;Q. Fang;Liu Changsong;Qun Huang;Yucheng Wu
用分子动力学模拟方法研究了反冲能在0.5-20 keV范围内碰撞级联在α-Fe中的初始损伤形成。介绍了两种近邻分析方法，即近邻缺陷密度（NPDD）分析和聚类分析，分别用于表征点缺陷的空间聚集和聚类形貌。结果表明，自填隙原子（SIA）的NPDD与Frenkel对数的变化趋势相似，而空位的NPDD出现峰值的时间比SIA短。此外，我们还发现，在级联的过程中和级联的末端，点缺陷团主要以链状结构的形式存在，但链状团的比例随着单个点缺陷团中点缺陷个数的增加而减小。因此，本文方法可以有效地用位移级联来表征点缺陷的聚集和近邻结构。
Molecular dynamics simulations have been performed to study the primary damage formation in α-Fe by collision cascades in the recoil energy range 0.5–20 keV. Two near-neighbor analysis methods including the near-neighbor defect density (NPDD) analysis and cluster analysis were introduced to characterize the spatial aggregation of point defects and the morphologies of clusters, respectively. It is found that the NPDD of self-interstitial atom (SIA) and the number of Frenkel pairs show a similar variation trend, while the NPDD of vacancy exhibits a peak at shorter time than that of SIA. Furthermore, we find that the clusters of point defects exist mostly in the form of chainlike structure in the course and the end of cascades, but the proportion of chainlike clusters decreases with increasing the number of point defects included in one cluster. Therefore, the present methods are found to be effective to characterize the aggregation and the near-neighbor structure of point defects by displacement cascades at...