Molecular dynamics simulations of irradiation defects in graphite: Single crystal mechanical and thermal properties
Molecular dynamics simulations of irradiation defects in graphite: Single crystal mechanical and thermal properties
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DOI：
10.1016/j.commatsci.2015.11.012
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发表时间：
2016-02-15
影响因子：
3.3
通讯作者：
Heggie, M. I.
中科院分区：
文献类型：
--
作者：
Trevethan, T.;Heggie, M. I.
已经对单晶石墨进行了分子动力学模拟，结合了由于热退火辐射损伤而形成的点和扩展缺陷结构。这些 AIREBO 电势计算模拟了由于扩展辐照引起的缺陷（空位和间隙聚集体）和一系列原子位移分数的不同代表性形态的形成而导致的晶体尺寸、弹性模量和热膨胀的变化。我们发现，除了模拟方法再现原始石墨的重要机械和热性能之外，石墨晶体结构中扩展缺陷的形成引起的性能变化在质量上与不同辐照/退火温度条件下的实验观察结果一致。这些计算结果可以直接洞察辐射损伤产生的潜在原子级缺陷和位错如何导致材料性能变化，并证明如何采用这种计算高效的模拟方法来重现多粒石墨大规模模型中的微晶变化。 (C) 2015 Elsevier B.V. 保留所有权利。
Molecular dynamics simulations of single crystal graphite have been performed, incorporating point and extended defect structures formed as a result of thermally annealed radiation damage. These AIREBO potential calculations have simulated the changes to crystal dimensions, elastic moduli and thermal expansion due to the formation of different representative morphologies of extended irradiation-induced defects (vacancy and interstitial aggregates) and over a range of atomic displacement fractions. We find that, in addition to the simulation method reproducing the important mechanical and thermal properties of virgin graphite, the property changes caused by the formation of extended defects in the graphite crystal structure qualitatively agree with experimental observations at different irradiation/annealing temperature regimes. The results of these calculations provide a direct insight into how the underlying atomic scale defects and dislocations created by radiation damage can lead to material property changes, and demonstrate how this computationally efficient simulation method can be employed to reproduce crystallite changes in large-scale models of polygranular graphite. (C) 2015 Elsevier B.V. All rights reserved.