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论文类型： 期刊论文

发表时间： 2012-03-01

发表刊物： ACS NANO

收录刊物： SCIE、EI、PubMed、Scopus

卷号： 6

期号： 3

页面范围： 2704-2711

ISSN号： 1936-0851

关键字： graphene; grain boundary; defects; tensile strain; intrinsic strength

摘要： As one-dimension line defects, grain boundaries (GBs) can affect many intrinsic properties of graphene. In this paper, the mechanical properties of 20 representative graphene grain boundaries were studied using density functional theory and molecular dynamics. With different arrangements of the pentagonal and heptagonal rings, the grain boundary may remain flat or become inflected up to 72. For the flat GBs, the intrinsic tensile strength decreases linearly with the formation energy with a maximum value of 93 GPa, close to that of a perfect graphene. The intrinsic tensile strength of the inflected GBs is found to generally decrease with increasing inflection angle. Stone-Wales transformation is identified as the major failure mechanism of graphene GBs at high temperatures, whereas the initial fracture site can be either on the boundary line or inside the domain. These theoretical results constitute a useful picture of the grain boundary effect on the mechanical properties of polycrystalline graphene.