One-dimensional atomic transport by clusters of self-interstitial atoms in iron and copper
One-dimensional atomic transport by clusters of self-interstitial atoms in iron and copper
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DOI：
10.1080/0141861021000016793
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发表时间：
2003-01-01
影响因子：
1.6
通讯作者：
Golubov, SI
中科院分区：
文献类型：
--
作者：
Osetsky, YN;Bacon, DJ;Golubov, SI
用原子尺度的计算机模拟研究了纯Cu和α - fe中自间隙原子（SIAs）以平面团簇形式的热激活原子输运。有强有力的证据表明，这种团簇在高能粒子辐照下在金属中普遍形成，对存活缺陷的积累和空间分布起着重要作用。利用分子动力学模拟技术，对含有2 ~ 331个间隙的SIA簇在180 ~ 1200 K温度范围内的迁移率进行了广泛的研究。结果表明，大于3 ~ 4个sia的簇在Cu和Fe中均具有一维可迁移性。铜中超过100个SIAs和铁中超过300个SIAs的大簇显著降低了迁移率。讨论了三维空间中一维运动的描述问题。尝试在近似ID扩散的情况下描述SIA簇的迁移性。对于两种金属中的团簇，通过团簇质量中心的跳跃频率估计的ID扩散的有效迁移能与团簇中SIAs的数量无关，尽管团簇的跳跃频率随着团簇大小的增加而降低。讨论了间隙簇的ID迁移机制。
Atomic-scale computer simulation has been used to study the thermally activated atomic transport of self-interstitial atoms (SIAs) in the form of planar clusters in pure Cu and alpha-Fe. There is strong evidence that such clusters are commonly formed in metals during irradiation with high-energy particles and play an important role in accumulation and spatial distribution of surviving defects. An extensive study of the mobility of SIA clusters containing two to 331 interstitials has been carried out using the molecular dynamics simulation technique for the temperature range from 180 to 1200 K. The results obtained show that clusters larger than three to four SIAs are one-dimensionally mobile in both Cu and Fe. Large clusters of more than 100 SIAs in Cu and 300 SIAs in Fe have significantly reduced mobility. The problem of describing one-dimensional (1D) motion in three-dimensional space is discussed. An attempt is made to describe the mobility of SIA clusters within the approximation of ID diffusion. For clusters in both metals the effective migration energy of ID diffusion as estimated-via the jump frequency of the cluster centre of mass is found to be independent of the number of SIAs in the clusters, although the cluster jump frequency decreases with increasing cluster size. Mechanisms of ID mobility of interstitial clusters are discussed.