Tailoring fracture strength of graphene

Abstract

We conducted molecular dynamics simulations to investigate the atomistic edge crack–vacancy interactions in graphene. We demonstrate that the crack–tip stress field of an existing crack in graphene can be effectively tailored (reduced by over 50% or increased by over 70%) by the strategic placement of atomic vacancies of varied shapes, locations, and orientations near its tip. The crack–vacancy interactions result in a remarkable improvement (over 65%) in the fracture strength of graphene. Moreover, at reduced stiffness of graphene, due to a distribution of atomic vacancies, a drastic difference (∼60%) was observed between the fracture strengths of two principal crack configurations (i.e. armchair and zigzag). Our numerical simulations provide a remarkable insight into the applicability of the well-established continuum models of crack–microdefect interactions for the corresponding atomic scale problems. Furthermore, we demonstrate that the presence of atomic vacancies in close proximity to the crack–tip leads to a multiple–stage crack growth and, more interestingly, the propagating cracks can be completely healed even under a significantly high applied tensile stress level (∼5 GPa). Our numerical experiments offer a substantial contribution to the existing literature on the fracture behavior of two–dimensional nanomaterials.

URL: http://www.sciencedirect.com/science/article/pii/S0927025617304755

Accepted version is available here: https://www.researchgate.net/publication/319992005_Tailoring_Fracture_St...