Mechanical properties of pristine and nanocrystalline graphene up to ultra-high temperatures

Despite being the basic building block of most carbon materials used in high and ultra-high temperature applications, mechanical properties graphene at such temperatures remain totally unknown. Here we compute these using tensile molecular dynamics simulations ranging from room to 5000 K (i. e. about melting temperature) for pristine nanocrystalline graphene. Mechanical are made possible via use screened environment dependent reactive empirical bond order potential [Perriot et al. Phys. Rev. B 88, 064101 (2013)]. We show that even highest temperature, both retain stiffness, strength fracture strain. Analyses curves trajectories (including an analysis in-plane non-affine atomic displacements) brittle rupture, whatever though some early sign ductility can be detected K. This rules out possibility a ductile any below point. Finally, also highlight importance rotation (Stone-Wales) based defects initiation mechanism Especially intermediate (3000 K) crack nucleation is shown take place exactly moment first Stone-Wales defect formation.