Simulation of the interaction between an edge dislocation and ⟨111⟩ interstitial dislocation loops in α-iron
Simulation of the interaction between an edge dislocation and ⟨111⟩ interstitial dislocation loops in α-iron
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模拟 α-铁中刃位错和 ⟨111⟩ 间隙位错环之间的相互作用
DOI：
10.1080/10420150.2018.1564922
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Y. Osetsky
中科院分区：
文献类型：
--
作者：
P. Grammatikopoulos;D. Bacon;Y. Osetsky
摘要<111>利用分子动力学（MD）模拟方法研究了中等尺寸半自填隙原子（SIA）环与刃型位错的相互作用对应变速率和温度的依赖关系。对于低温（T = 1 K），相互作用的机制与最近的文献。结果表明，位错通过环的第二次通过导致与第一次通过时发生的机制不同的机制。由于这些机制与不同的SIA回路大小相关，并且由于回路在第一次相互作用时丢失了许多SIA，因此推断出大回路和小回路之间的划分阈值（分别使它们成为强障碍物或弱障碍物）在所研究的回路大小（169个SIA）附近。对于较高的温度（T = 300 K），应变率的依赖性证明是强的：低应变率，位错吸收的循环作为一个双超慢跑几乎立即继续其滑行畅通无阻。对于高应变速率，位错最初被钉扎，由于形成几乎无座的段，导致高的临界应力。
ABSTRACT The dependence of the interactions of intermediate-size ½<111> self-interstitial atom (SIA) loops with an edge dislocation on strain rate and temperature was investigated by molecular dynamics (MD) simulations for the interatomic potential derived by Ackland et al. (A97). For low temperatures (T = 1 K), the mechanisms of the interactions were in agreement with recent literature. It was shown that a second passing of the dislocation through the loop led to a different mechanism than the one that occurred upon first passing. Since these mechanisms are associated with different SIA loop sizes, and since the loop lost a number of SIAs upon first interaction, it was deduced that the dividing threshold between large and small loops (rendering them strong or weak obstacles, respectively) is at the vicinity of the loop size studied (169 SIAs). For higher temperatures (T = 300 K), the strain rate dependence proved strong: for low strain rates, the dislocation absorbed the loop as a double super-jog almost immediately and continued its glide unimpeded. For a high strain rate, the dislocation was initially pinned due to the formation of an almost sessile segment leading to high critical stress.