Atomistic Computational Analysis of the Loading Orientation-Dependent Phase Transformation in Graphite under Compression
Atomistic Computational Analysis of the Loading Orientation-Dependent Phase Transformation in Graphite under Compression
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DOI：
10.1007/s11837-019-03726-y
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发表时间：
2019-08
期刊：
影响因子：
2.6
通讯作者：
Yipeng Peng;Liming Xiong
中科院分区：
文献类型：
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作者：
Yipeng Peng;Liming Xiong
在这项工作中，我们进行了原子模拟来研究石墨在压缩下的相变（PT）。主要研究结果如下：(1)当压缩平行于基底面时，石墨层发生屈曲，形成扭结带，然后在扭结带的交点处形成金刚石形核；初始引入的位错阻止了石墨层的滑移，促进了石墨-金刚石PT的生成；(2)相反，当试样垂直于基面压缩时，没有观察到屈曲现象，在这种情况下，已有的位错延迟了结构的变化；(3)发现PT受局部应力控制，由此可以制定检测石墨晶格不稳定性的准则。尽管我们的原子模型的长度尺度有限，但上述结果可能支持寻找制造人造钻石的新路线，其成本明显低于传统技术所需的成本。
In this work, we perform atomistic simulations to study the phase transformations (PT) in graphite under compression. Our major findings are: (1) when the compression is parallel to the basal plane, graphite layers buckle, kink bands form, and then the diamond nucleates at the intersection of kink bands; the initially introduced dislocations block the graphite layer slippage and promote the graphite-to-diamond PT; (2) instead, when the sample is compressed normal to the basal plane, no buckling is observed, and in this situation, the pre-existing dislocations delay the structure change; and (3) the PT is found to be controlled by local stresses from which a criterion can be formulated for detecting the graphite lattice instability. Despite the limited length scales in our atomistic models, the above results may support the search for new routes to fabricate artificial diamonds at a significantly less cost than that required by traditional techniques.