Fracture toughness of graphene.
Perfect graphene is believed to be the strongest material. However, the useful strength of large-area graphene with engineering relevance is usually determined by its fracture toughness, rather than the intrinsic strength that governs a uniform breaking of atomic bonds in perfect graphene. To date, the fracture toughness of graphene has not been measured. Here we report an in situ tensile testing of suspended graphene using a nanomechanical device in a scanning electron microscope. During tensile loading, the pre-cracked graphene sample fractures in a brittle manner with sharp edges, at a breaking stress substantially lower than the intrinsic strength of graphene. Our combined experiment and modelling verify the applicability of the classic Griffith theory of brittle fracture to graphene. The fracture toughness of graphene is measured as the critical stress intensity factor of and the equivalent critical strain energy release rate of 15.9 J m(-2). Our work quantifies the essential fracture properties of graphene and provides mechanistic insights into the mechanical failure of graphene.
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Peng
P
Zhang
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Lulu
L
Ma
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Feifei
F
Fan
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Zhi
Z
Zeng
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Cheng
C
Peng
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Phillip E
PE
Loya
1] Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA [2] School of Materials Science and Engineering, School of Electrical and Electronic Engineering, Nanyang Technological University, 639798 Singapore.
Zheng
Z
Liu
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Yongji
Y
Gong
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Jiangnan
J
Zhang
Institute of Functional Fibers, Tianjin Polytechnic University, Tianjin 300387, China.
Xingxiang
X
Zhang
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Pulickel M
PM
Ajayan
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Ting
T
Zhu
Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
Jun
J
Lou
D006108:Graphite / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods* / Q000706:statistics & numerical data; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D013718:Tensile Strength
D006108:Graphite