Graphene with dislocation dipoles: Wrinkling and defect nucleation during tension

Abstract

Graphene is a promising material with high strength that can be reduced by the presence of defects. Defect engineering can be an effective way of property control for such two-dimensional structures like graphene. In the present work, the mechanical properties of graphene with dislocation dipoles under uniaxial tension have been studied using molecular dynamics. A dislocation dipole consists of two heptagon–pentagon pairs (dislocations) separated by a dipole arm with length from 0 to 30 Å. Graphene wrinkling is allowed to reveal the underlying deformation mechanisms. Tensile deformation was applied at temperatures ranging from 0 to 3000 K. The tensile strength of defect-free graphene and graphene with Stone–Wales defect is more sensitive to temperature and loading direction than that of graphene with dislocation dipoles. The value of the dipole arm has no significant effect on the fracture strain and stress, but the presence of any dipole significantly reduces the fracture strain. With increasing temperature, the tensile strength and the anisotropy of the mechanical properties decrease. The present study provides insight into the behavior of defective graphene under uniaxial tension, which will help in its application in the design of next-generation flexible devices.