Probing Atomic-Scale Fracture of Grain Boundaries in Low-symmetry 2D Materials

Hui Zhang; Yue Yu; Xinyue Dai; Jinshan Yu; Hua Xu; Shanshan Wang; Feng Ding; Jin Zhang

doi:10.1002/smll.202102739

Probing Atomic-Scale Fracture of Grain Boundaries in Low-symmetry 2D Materials

Small. 2021 Dec;17(51):e2102739. doi: 10.1002/smll.202102739. Epub 2021 Oct 13.

Authors

Hui Zhang¹, Yue Yu², Xinyue Dai^{3

4}, Jinshan Yu¹, Hua Xu⁵, Shanshan Wang^{1

2}, Feng Ding^{3

6}, Jin Zhang²

Affiliations

¹ Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410000, P. R. China.
² Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China.
³ Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea.
⁴ School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
⁵ Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China.
⁶ School of Materials Science and Engineering, Ulsan, National Institute of Science and Technology, Ulsan, 44919, South Korea.

PMID: 34643318
DOI: 10.1002/smll.202102739

Abstract

Grain boundaries (GBs) play a central role in the fracture of polycrystals. However, the complexity of GBs and the difficulty in monitoring the atomic structure evolution during fracture greatly limit the understanding of the GB mechanics. Here, in situ aberration-corrected scanning transmission electron microscopy and density functional theory calculations are combined to investigate the fracture mechanics in low-symmetry, polycrystalline, 2D rhenium disulfide (ReS₂ ), unveiling the distinctive crack behaviors at different GBs with atomic resolution. Brittle intergranular fracture prefers to rip through the GBs that are parallel to the Re chains of at least one side of the GBs. In contrast, those GBs, which do not align with Re chains on either side of the GBs, are highly resistant to fracture, impeding or deflecting the crack propagation. These results disclose the GB type-dependent mechanical failure of anisotropic 2D polycrystals, providing new ideas for material reinforcement and controllable cutting via GB engineering.

Keywords: 2D materials; atomic scale; density functional theory; fracture mechanics; grain boundaries; low symmetry; scanning transmission electron microscopy.

Abstract

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