Non-affine atomic rearrangement of glasses through stress-induced structural anisotropy
Non-affine atomic rearrangement of glasses through stress-induced structural anisotropy
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DOI：
10.1038/s41567-023-02243-9
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发表时间：
2023-10
期刊：
影响因子：
19.6
通讯作者：
Jie Dong;Hailong Peng;Hui Wang;Yang Tong;Yutian Wang;Wojtek Dmowski;Takeshi Egami;Baoan Sun;Weihua Wang;Haiyang Bai
中科院分区：
文献类型：
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作者：
Jie Dong;Hailong Peng;Hui Wang;Yang Tong;Yutian Wang;Wojtek Dmowski;Takeshi Egami;Baoan Sun;Weihua Wang;Haiyang Bai
玻璃在外加应力下的原子尺度结构重排对于理解其宏观力学性能和行为至关重要。然而，由于玻璃结构的无序性质，通过实验解决变形玻璃的原子尺度结构变化仍然具有挑战性。传统的结构分析，如X射线衍射是基于结构各向同性的假设，因此不能辨别微妙的原子尺度的结构重排引起的变形。在这里，我们表明，结构各向异性与非仿射原子位移，这意味着那些不保留原子结构中的平行线，在各种类型的玻璃。这是一种识别玻璃中原子尺度非仿射变形的方法。我们还揭示了原子级机制负责塑性流动，这是金属玻璃和共价玻璃之间的不同。金属玻璃中的非仿射结构重排是通过原子键的伸缩来实现的。共价玻璃的非亲和性以不太局部化的方式发生，通过原子键或链的旋转介导，而不改变键长。这些发现提供了关键成分探索原子尺度的过程中的宏观变形的无定形固体。
The atomic-scale structural rearrangement of glasses on applied stress is central to the understanding of their macroscopic mechanical properties and behaviour. However, experimentally resolving the atomic-scale structural changes of a deformed glass remains challenging due to the disordered nature of the glass structure. Conventional structural analyses such as X-ray diffraction are based on the assumption of structural isotropy and hence cannot discern the subtle atomic-scale structural rearrangement induced by deformation. Here we show that structural anisotropy correlates with non-affine atomic displacements—meaning those that do not preserve parallel lines in the atomic structure—in various types of glass. This serves as an approach for identifying the atomic-scale non-affine deformation in glasses. We also uncover the atomic-level mechanism responsible for plastic flow, which differs between metallic glasses and covalent glasses. The non-affine structural rearrangements in metallic glasses are mediated through the stretching or contraction of atomic bonds. The non-affinity of covalent glasses that occurs in a less localized manner is mediated through the rotation of atomic bonds or chains without changing the bond length. These findings provide key ingredients for exploring the atomic-scale process governing the macroscopic deformation of amorphous solids.