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Local Deformation of Glasses is Mediated by Rigidity Fluctuation on Nanometer Scale
Advanced Science ( IF 14.3 ) Pub Date : 2018-08-29 , DOI: 10.1002/advs.201800916 Omar Benzine 1 , Sebastian Bruns 2 , Zhiwen Pan 1 , Karsten Durst 2 , Lothar Wondraczek 1, 3
Advanced Science ( IF 14.3 ) Pub Date : 2018-08-29 , DOI: 10.1002/advs.201800916 Omar Benzine 1 , Sebastian Bruns 2 , Zhiwen Pan 1 , Karsten Durst 2 , Lothar Wondraczek 1, 3
Affiliation
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Microscopic deformation processes determine defect formation on glass surfaces and, thus, the material's resistance to mechanical failure. While the macroscopic strength of most glasses is not directly dependent on material composition, local deformation and flaw initiation are strongly affected by chemistry and atomic arrangement. Aside from empirical insight, however, the structural origin of the fundamental deformation modes remains largely unknown. Experimental methods that probe parameters on short or intermediate length‐scale such as atom–atom or superstructural correlations are typically applied in the absence of alternatives. Drawing on recent experimental advances, spatially resolved Raman spectroscopy is now used in the THz‐gap for mapping local changes in the low‐frequency vibrational density of states. From direct observation of deformation‐induced variations on the characteristic length‐scale of molecular heterogeneity, it is revealed that rigidity fluctuation mediates the deformation process of inorganic glasses. Molecular field approximations, which are based solely on the observation of short‐range (interatomic) interactions, fail in the prediction of mechanical behavior. Instead, glasses appear to respond to local mechanical contact in a way that is similar to that of granular media with high intergranular cohesion.
中文翻译：
玻璃的局部变形是由纳米级的刚度波动介导的
微观变形过程决定了玻璃表面缺陷的形成，从而决定了材料的抗机械故障能力。虽然大多数玻璃的宏观强度并不直接取决于材料成分，但局部变形和缺陷萌生受到化学和原子排列的强烈影响。然而，除了经验洞察之外，基本变形模式的结构起源在很大程度上仍然未知。在短或中长度尺度上探测参数（例如原子-原子或超结构相关性）的实验方法通常在没有替代方案的情况下应用。利用最近的实验进展，空间分辨拉曼光谱现在用于太赫兹能隙，用于绘制低频振动状态密度的局部变化。通过直接观察变形引起的分子异质性特征长度尺度的变化，揭示了刚性波动介导了无机玻璃的变形过程。分子场近似仅基于对短程（原子间）相互作用的观察，无法预测机械行为。相反，玻璃对局部机械接触的反应似乎与具有高颗粒间内聚力的颗粒介质类似。
更新日期：2018-08-29
中文翻译：
玻璃的局部变形是由纳米级的刚度波动介导的
微观变形过程决定了玻璃表面缺陷的形成，从而决定了材料的抗机械故障能力。虽然大多数玻璃的宏观强度并不直接取决于材料成分，但局部变形和缺陷萌生受到化学和原子排列的强烈影响。然而，除了经验洞察之外，基本变形模式的结构起源在很大程度上仍然未知。在短或中长度尺度上探测参数（例如原子-原子或超结构相关性）的实验方法通常在没有替代方案的情况下应用。利用最近的实验进展，空间分辨拉曼光谱现在用于太赫兹能隙，用于绘制低频振动状态密度的局部变化。通过直接观察变形引起的分子异质性特征长度尺度的变化，揭示了刚性波动介导了无机玻璃的变形过程。分子场近似仅基于对短程（原子间）相互作用的观察，无法预测机械行为。相反，玻璃对局部机械接触的反应似乎与具有高颗粒间内聚力的颗粒介质类似。
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