Dislocation Shielding of a Nanocrack in Graphene: Atomistic Simulations and Continuum Modeling

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• 作者：Fanchao Meng ; Cheng Chen ; Jun Song
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：October 15, 2015
• 年：2015
• 卷：6
• 期：20
• 页码：4038-4042
• 全文大小：414K
• ISSN：1948-7185

文摘

Combining atomistic simulations and continuum modeling, we studied dislocation shielding of a nanocrack in monolayer graphene under mode-I loading. Different crack-dislocation configurations were constructed and the shielding effects on the threshold stress intensity for crack propagation were examined. Excellent agreement between simulation results and linear-elastic fracture mechanics (LEFM) predictions was achieved. As the separation between the crack-tip and dislocation, that is, r_R, varies (with respect to the crack size a), the shielding effect exhibits two different dependences on r_R, scaling as 1/r_R^1/2 for r_R/a 鈮?1 (near-tip), whereas 1/r_R for r_R/a 鈮?1 (far-field), respectively. Particularly, the far-field 1/r_R scaling was shown to be a direct manifestation of the stress field of dislocation in graphene. Our work presents a systematic study of nanoscale crack-dislocation interactions in graphene, providing valuable information on defect engineering of graphene.