Toughening two dimensional materials through lattice disorder

WH Xie and XB Zhang and YJ Wei and HJ Gao, CARBON, 213, 118268 (2023).

DOI: 10.1016/j.carbon.2023.118268

Carbon-based two-dimensional (2D) materials, with graphene being the most prominent example, are some of the strongest materials existing today due to their covalent bonding but at the same time also the most fragile, with fracture toughness close to that of an ideally brittle solid, due to their intrinsic lack of effective dissipation mechanisms. Here, by investigating fracture mechanisms in monolayer amorphous carbon (MAC), we reveal a novel strategy to toughen 2D materials through lattice disorder. It is shown that lattice disorder results in rippling which can alleviate stress concentration in the vicinity of crack-tips and render MAC flaw tolerant. Consequently, MAC outperforms graphene in resisting brittle fracture and endures larger strain to failure in the presence of a preexisting crack. Our work sheds light on the mechanisms of crack propagation in MAC and also suggests that it might be generally possible to design tough 2D materials through lattice disorder.

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