Comparison of Biotite Elastic Properties Recovered by Spherical Nanoindentations and Atomistic Simulations — Influence of Nano‐Scale Defects in Phyllosilicates
Comparison of Biotite Elastic Properties Recovered by Spherical Nanoindentations and Atomistic Simulations — Influence of Nano‐Scale Defects in Phyllosilicates
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球形纳米压痕和原子模拟恢复的黑云母弹性性能的比较 – 页硅酸盐中纳米级缺陷的影响
DOI：
10.1029/2021jb021902
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Wang, Bu
中科院分区：
文献类型：
--
作者：
Lanin, Eril Suhada;Sone, Hiroki;Yu, Zheng;Liu, Qitong;Wang, Bu
层状硅酸盐矿物，由于它们的片状结构和形态，已知会引起块体岩石性质的各向异性，并使块体岩石更柔顺。从实验室观察中准确表征层状硅酸盐矿物的微观力学行为，最终转化为大块岩石的行为，由于其细粒性质，仍然具有挑战性。原子模拟的最新进展为从理论上研究这种矿物的力学行为提供了可能。我们比较的弹性性质的黑云母恢复球形纳米压痕与密度泛函理论（DFT）模拟预测的研究在何种程度上的理论预测重现实际页硅酸盐性质。利用美国南达科他州Poorman地层的片岩进行球形纳米压痕，以恢复连续的压痕应力应变曲线。层法向加载显示平均压痕模量（）约为35 GPa，而层平行方向加载显示平均值更高，约为95 GPa。为了便于比较，使用本研究中提出的解决方案将DFT确定的弹性刚度常数（cij）转换为压痕模量（）。大多数纳米压痕模量结果低于从代表理想无缺陷矿物的模拟结果推断的值。我们认为，在纳米尺度上存在的晶体缺陷，潜在的ripplocations，是较低的压痕模量从纳米压痕相比，从DFT模拟推断的主要原因。结果强调了承认存在纳米级缺陷的重要性，因为与纯无缺陷形式相比，它改变了层状硅酸盐的机械性能。
Phyllosilicate minerals, due to their sheets structure and morphology, are known to cause anisotropy in bulk rock properties and make the bulk rock more compliant. Accurately characterizing the micromechanical behavior of phyllosilicate minerals from laboratory observations, which eventually translates to the bulk rock behavior, is still challenging due to their fine‐grained nature. Recent advances in atomistic simulations open the possibility of theoretically investigating such mineral mechanical behavior. We compare the elastic properties of biotites recovered by spherical nanoindentation with those predicted from density functional theory (DFT) simulations to investigate to what extent theoretical predictions reproduce actual phyllosilicate properties. Spherical nanoindentation was conducted using schist rocks from Poorman Formation, South Dakota, USA, to recover continuous indentation stress‐strain curves. Loading in the layer‐normal orientation shows an average indentation modulus () of about 35 GPa, while loading in the layer‐parallel orientation gives a higher average of about 95 GPa. To facilitate comparison, the elastic stiffness constants (cij) determined from DFT were converted to indentation modulus () using solutions proposed in this study. The majority of the nanoindentation modulus results are below the values inferred from the simulation results representing ideal defect‐free minerals. We suggest that crystal defects present at the nano‐scale, potentially ripplocations, are the dominant cause of the lower indentation modulus recovered from nanoindentation compared to those inferred from DFT simulations. Results highlight the importance of acknowledging the defects that exist down to the nano‐scale as it modifies the mechanical properties of phyllosilicates compared to its pure defect‐free form.
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影响因子：
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影响因子：
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DOI：
--
发表时间：
2014
期刊：
影响因子：
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作者：
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通讯作者：
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DOI：
--
发表时间：
2007
期刊：
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