Mechanical Properties of Polycrystalline and Defective Graphene
Ivan Oleynik1*
1Department of Physics, University of South Florida, Tampa, FL, USA
* presenting author:Ivan Oleynik,
Experimental investigation of mechanical properties indicates that the polycrystalline graphene grown by chemical vapor deposition is as strong as pristine. Recent experiments involving nanoindentation of defective graphene have also demonstrated counterintuitive increasing of Young’s modulus with increasing concentrations of point defects. Using accurate description of interatomic interactions provided by novel screened environment-dependent bond order (SED-REBO) potential, we performed large-scale molecular dynamics investigations of mechanical properties of polycrystalline and defective graphene samples under conditions mimicking nano-indentation AFM experiments. The atomically resolved characterization of the stress and strain distributions under indenter are used to understand fundamental mechanisms of graphene strength and failure. The breaking strength, the crack initiation and propagation are investigated as a function of the grain boundary structure, grain size distribution, concentration of point defects as well as the position of the indenter in respect to these extended and point defects.

Keywords: graphene, mechanical properties, grain boundaries, point defects, molecular dynamics