Figure 2. The correlations between the grain size and mechanical properties.

(a) The tensile stress-strain curves for polycrystalline graphene with the average grain sizes of 3, 5, 7, 9, and 11 nm. All simulations are performed at a strain rate of 4 × 10⁷ s⁻¹. (b–d) The trends of the Young's modulus, the failure strain, and the breaking strength as a function of the grain size, respectively.