Figure 3
From: On the failure load and mechanism of polycrystalline graphene by nanoindentation
The rupture processes of polycrystalline graphene for the different indentation locations.
The indenter tip is positioned on (a) grain center, (b) the same as (a) but with a hole at a GB junction, (c) GB, (d) GB junction and (e) hole, respectively. The dotted circles indicate the initial crack formation. The close-up views of these crack formations are shown in the right panels. For clarity, the indenter tip is not shown. The rupture of polycrystalline graphene starts from a GB when the indenter tip is positioned on the center of grain, while the rupture of polycrystalline graphene starts directly from a defect when the indenter tip is positioned on the defect. Evidently, the failure behavior of polycrystalline graphene is dependent on the indentation location.
