| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Monday Sessions |
| Session 2D+EM+MI+NS-MoM |
| Session: | Properties of 2D Materials including Electronic, Magnetic, Mechanical, Optical, and Thermal Properties I |
| Presenter: | Teng Cui, University of Toronto, Canada |
| Authors: | T. Cui, University of Toronto, Canada S. Mukherjee, University of Toronto, Canada P.M. Sudeep, University of Toronto, Canada G. Colas, University of Toronto, Canada J. Tam, University of Toronto, Canada P.M. Ajayan, Rice University C.V. Singh, University of Toronto, Canada Y. Sun, University of Toronto, Canada T. Filleter, University of Toronto, Canada |
| Correspondent: | Click to Email |
Materials can fail when subjected to cyclic loading at stress levels much lower than the ultimate tensile strength or yielding limit, which is known as mechanical fatigue. Understanding the fatigue behavior is critical for any emerging material in order to evaluate its long-term dynamic reliability. Two-dimensional (2D) materials have been widely applied to mechanical and electronic applications, where they are commonly subjected to cyclic stress. However, the fatigue life and underlying damage mechanisms of these atomically thin, nearly defect-free, materials are unknown. Here we show the first fatigue study of freestanding 2D materials, in particular graphene and graphene oxide (GO). Monolayer and few layer graphene and GO were found to all exhibit ultrahigh fatigue life of more than one billion cycles at large stress level in the GPa range. Such a remarkable fatigue life is higher than that of any material reported to date at similar stress levels. Graphene exhibits global and catastrophic fatigue failure preceded by bond reconfiguration near the defective site due to inhomogeneous charge distribution and higher potential energy. Graphene can fracture under cyclic loading but without progressive damage, which is distinct from the fatigue failure mechanism of any other materials. The presence of functional groups on GO imparts a local and progressive fatigue damage mechanism, which fits the macroscopic fatigue convention. The extraordinary fatigue life was found to diminish significantly when the material is scaled up in thickness (10s of layers). This work not only provides new fundamental insights into the widely observed fatigue enhancement behavior of graphene-embedded nanocomposites, but also serves as a starting point for the mechanical dynamic reliability evaluation of other 2D materials.