在质子排序的六角冰中基底位移
1Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, USA.
The Journal of chemical physics
|July 23, 2025
概括
六角冰中的质子排序并没有缓解脱位滑动. 分子动力学揭示了特定的脱位保持静止,其中一些只在高应力下移动,影响了塑料流理论.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 计算化学计算化学
背景情况:
- 六角冰 (冰I) 呈现出复杂的质子排序,特别是在低温阶段 (冰XI).
- 脱位滑动是晶体固体 (包括冰) 中塑性变形的主要机制.
- 了解脱位行为对于预测各种条件下冰的机械性质至关重要.
研究的目的:
- 为了研究核心结构和关键解决的剪切应力,在质子排序的六角冰中进行基底位位滑动.
- 为了确定不同类型的位移的移动性 (直线,扭曲,60°,螺丝) 在混合和滑动设置平面上.
- 评估质子排序对易于排位运动的影响.
主要方法:
- 用分子动力学 (MD) 模拟来建模脱位行为.
- 分析的重点是核心结构和关键解决剪切应力 (CRSS) 的计算,用于位运动.
- 模拟检查了六角冰格内的混合和滑动设置平面上的位移.
主要成果:
- 大多数研究的脱位,包括螺旋和扭曲型,被发现是性的,需要高分辨率的剪切应力 (≥0.11) 来实现运动.
- 直接的60°混合位移表现出不同的CRSS,取决于核心定向和加载方向.
- 最低的观察到的模量正常化CRSS直线60°混合位移是0.044,相当于钻石中的皮尔尔斯屏障. 扭曲可以阻碍或减少这种压力到0.037.
- 发现六角冰中的质子排序并不能促进脱位滑动.
结论:
- 质子排序并没有显著降低六角冰中基底位位滑动的能量屏障.
- 大多数脱位的性质表明,在典型条件下,质子排列冰中的塑料流量有限.
- 这些发现需要对现有的关于冰I和冰XI的塑性流动理论进行重新评估.
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