空位缺陷对单层石墨烯薄膜拉伸力学性能的影响

Effect of Vacancy Defects on Tensile Mechanical Properties of Single Graphene Sheets

摘要:

采用Tersoff势对完美的和含空位缺陷的单层石墨烯薄膜的单向拉伸力学性能进行了分子动力学模拟,分别研究了单个单原子空位缺陷和单个双原子空位缺陷对扶手椅型和锯齿型石墨烯拉伸力学性能及变形机制的影响.研究结果表明,单原子空位缺陷和双原子空位缺陷对扶手椅型和锯齿型石墨烯薄膜的杨氏模量没有影响,但在一定程度上降低了拉伸强度和拉伸极限应变.单原子空位缺陷和双原子空位缺陷使拉伸强度降低幅度最高达8.10%和6.41%,并大幅度降低极限应变.缺陷对石墨烯的拉伸变形破坏机制也有一定的影响.在外载作用下,新的缺陷的萌生位置均出现在空位缺陷附近.

Abstract:

The effect of single one-and two-atom vacancy defects on the tensile mechanical properties and deformation mechanism of the zigzag and armchair single graphene sheets was investigated using molecular dynamics simulation with Tersoff bond-order interatomic potential.The numerical simulation results show that there is no effect on the Young’s modulus of the graphene due to the presence of vocancy defects,but there is a reduction in the tensile strength and failure strain.One-and two-atom vacancy defects are observed to reduce tensile stresses by as much as 8.10% and 6.41%,respectively,and markedly reduce failure strains.The defects also affect the deformation mechanism of graphene sheets under tention.In most cases,defects serve as nucleation site for fracture.