Original Article
  • Grain Size Effect on Mechanical Properties of Polycrystalline Graphene
  • Youngho Park*, Sangil Hyun*†, Myoungpyo Chun*
  • *Korea Institute of Ceramic Engineering and Technology, Jinju 52851, Korea; *†Korea Institute of Ceramic Engineering and Technology, Jinju 52851, Korea
Abstract
Characteristics of nanocrystalline materials are known substantially dependent on the microstructure such as grain size, crystal orientation, and grain boundary. Thus it is desired to have systematic characterization methods on the various nanomaterials with complex geometries, especially in low dimensional nature. One of the interested nanomaterials would be a pure two-dimensional material, graphene, with superior mechanical, thermal, and electrical properties. In this study, mechanical properties of "polycrystalline" graphene were numerically investigated by molecular dynamics simulations. Subdomains with various sizes would be generated in the polycrystalline graphene during the fabrication such as chemical vapor deposition process. The atomic models of polycrystalline graphene were generated using Voronoi tessellation method. Stress strain curves for tensile deformation were obtained for various grain sizes (5~40 nm) and their mechanical properties were determined. It was found that, as the grain size increases, Young's modulus increases showing the reverse Hall-Petch effect. However, the fracture strain decreases in the same region, while the ultimate tensile strength (UTS) rather shows slight increasing behavior. We found that the polycrystalline graphene shows the reverse Hall-Petch effect over the simulated domain of grain size (< 40 nm).

Keywords: Polycrystalline graphene, Molecular dynamics, Mechanical properties, Fracture strain, Hall-Petch effect

This Article

  • 2016; 29(6): 375-378

    Published on Dec 31, 2016

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