The role of cascade energy and temperature in primary defect formation in iron
The role of cascade energy and temperature in primary defect formation in iron
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DOI：
10.1016/s0022-3115(99)00204-4
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发表时间：
2000-01-01
影响因子：
3.1
通讯作者：
Stoller, RE
中科院分区：
文献类型：
--
作者：
Stoller, RE
分子动力学（MD）模拟研究了铁中原子位移级联的形成，在100 K时能量高达50 keV（对应于79 keV的初级撞击原子（PKA）能量），在600 K时高达20 keV，在900 K时高达10 keV。级联损伤产生的特征在于几个参数：幸存点缺陷的数量、簇中发现的幸存点缺陷的比例和类型以及级联点缺陷簇的尺寸分布。已经完成了足够数量的模拟在每个条件下，以评估这些主要的损伤参数作为辐射温度和级联能量的函数的统计变化。稳定缺陷形成的能量依赖性可以方便地分为三个区域，每个区域中的缺陷数量由一个简单的幂律与特征指数相关。在高能量的缺陷形成的级联能量的主要影响解释的子级联形成。只有一个温和的温度上观察到的缺陷生存的影响，而辐照温度的增加导致在级联间隙聚类分数略有增加，并在空位聚类分数的减少。级联能量在约5 keV以上的级联聚类分数的影响很小。然而，团簇大小分布存在系统性变化，较高的能量级联产生更大的团簇。级联空位团簇的松散耦合性质在较高的能量下持续存在。(C)2000 Elsevier Science B.V.保留所有权利。
Molecular dynamics (MD) simulations have been used to investigate the formation of atomic displacement cascades in iron with energies up to 50 keV (corresponding to a primary knock-on atom (PKA) energy of 79 keV) at 100 K, up to 20 keV at 600 K, and up to 10 keV at 900 K. The cascade damage production has been characterized in terms of several parameters: the number of surviving point defects, the fraction and type of surviving point defects found in clusters, and the size distributions of the in-cascade point defect clusters. A sufficient number of simulations have been completed at each condition to evaluate the statistical variation in these primary damage parameters as a function of irradiation temperature and cascade energy. The energy dependence of stable defect formation can be conveniently separated into three regimes with the number of defects in each regime correlated by a simple power law with a characteristic exponent. The primary effects of cascade energy on defect formation at high energies are explained in terms of subcascade formation. Only a modest effect of temperature is observed on defect survival, while irradiation temperature increases lead to a slight increase in the in-cascade interstitial clustering fraction and a decrease in the vacancy clustering fraction. Cascade energy has little effect on the in-cascade clustering fractions above about 5 keV. However, there is a systematic change in the cluster size distribution, with higher energy cascades producing larger clusters. The loosely coupled nature of the in-cascade vacancy clusters persists at higher energies. (C) 2000 Elsevier Science B.V. All rights reserved.