Pseudo Hall–Petch Strength Reduction in Polycrystalline Graphene

• Autor: Song, Zhigong ; Artyukhov, Vasilii I ; Yakobson, Boris I ; Xu, Zhiping
• Assuntos: Computer Simulation ; Condensed matter: structure, mechanical and thermal properties ; Cross-disciplinary physics: materials science; rheology ; Dislocations ; Elastic Modulus ; Exact sciences and technology ; Failure ; Fracture mechanics ; Fullerenes and related materials; diamonds, graphite ; Graphene ; Graphite - chemistry ; Materials science ; Mechanical and acoustical properties of condensed matter ; Mechanical properties of nanoscale materials ; Models, Chemical ; Molecular Dynamics Simulation ; Nanoparticles - chemistry ; Nanostructure ; Nanostructures ; Particle Size ; Physics ; Reduction ; Specific materials ; Strength ; Surface Properties
• É parte de: Nano letters, 2013-04, Vol.13 (4), p.1829-1833
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• Descrição: The fracture of polycrystalline graphene is explored by performing molecular dynamics simulations with realistic finite-grain-size models, emphasizing the role of grain boundary ends and junctions. The simulations reveal a ∼50% or more strength reduction due to the presence of the network of boundaries between polygonal grains, with cracks preferentially starting at the junctions. With a larger grain size, a surprising systematic decrease of tensile strength and failure strain is observed, while the elastic modulus rises. The observed crack localization and strength behavior are well-explained by a dislocation-pileup model, reminiscent of the Hall–Petch effect but coming from different underlying physics.
  
• Editor: Washington, DC: American Chemical Society
  
• Idioma: Inglês