在冲击条件下,石墨的转化机制变成六角形钻石
Gu-Wen Chen1, Sheng-Cai Zhu1, Liang Xu2
1School of Materials, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
JACS Au
|September 27, 2024
概括
冲击强度决定了钻石相位的形成. 高冲击强度有利于转移稳定的六角钻石,而低冲击强度产生立方钻石,澄清了一个关键的材料科学.
科学领域:
- 材料科学 材料科学 材料科学
- 计算材料科学科学 计算材料科学
- 固态物理 固态物理
背景情况:
- 在冲击条件下形成六角形钻石是材料科学中一个长期存在的难题.
- 冲击强度影响相位选择性的确切机制 (六角形与立方形钻石) 尚不清楚.
研究的目的:
- 为了研究冲击诱导的石墨到钻石过渡机制.
- 阐明冲击强度如何决定得到的钻石相 (六角形或立方形).
- 为强度依赖过渡提供第一原则的计算证据.
主要方法:
- 使用密度功能理论 (DFT) 训练的碳全球神经网络模型.
- 在不同冲击强度下模拟冲击诱导的石墨过渡.
- 分析了由此产生的钻石结构和方位关系.
主要成果:
- 高强度冲击,具有有限的滑动时间,导致具有特定方向关系的元稳定六角钻石 ((001) G//(100) HD+[010]G//[010]HD).
- 低强度的冲击,允许更长的滑动距离,导致立方钻石的形成与不同的方向关系 ((001) G//(111) CD+[100]G//[110]CD).
- 揭示了一个明确的依赖强度的机制,控制了石墨过渡.
结论:
- 从第一原则提供了第一个依赖强度的石墨过渡的计算证据.
- 澄清了冲击诱导的六角形钻石形成背后的机制.
- 确定了强度依赖趋势的结构起源,有助于控制的六角钻石合成.
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