▎ 摘　　要

Understanding the mechanical properties of grain boundaries (GB) in graphene is critical to commercial realization of large-area graphene in a vast array of applications. Previous pursuits on this topic mainly deal with tilt GBs, overlooking rotational GBs. Rotational GBs are composed of pentagon-heptagon pairs and are observed in mass-produced graphene. Herein, molecular dynamics simulations were conducted to determine the effect of GB curvature on the mechanical properties of graphene. While there was minimal effect on the Young's Modulus (less than 5%), a Weibull distribution-based analysis revealed weakening of strength and strain to failure with decreasing grain boundary curvature (by up to 23 GPa). Mechanical failure in rotational GBs was observed to occur by catastrophic failure of C-C bonds parallel to the tensile axis either away from or on the GB, differing by the initiating failure event depending on GB curvature. At higher GB curvatures, initial failure occurred in the bulk away from the GB. At lower GB curvatures, however, failure was initiated by a pseudo-plastic bond rotation, which propagated to catastrophic failure under increasing applied stress. Mitigation of crack propagation at lower curvatures was observed by the formation of monoatomic carbon chains, prolonging material survival under an applied stress. (C) 2019 Elsevier Ltd. All rights reserved.