Tunable Poisson's ratio and tension-compression asymmetry of graphene- copper nanolayered composites

S Zhang and Q Zhang and XY Liu and SN Luo, JOURNAL OF PHYSICS D-APPLIED PHYSICS, 54, 165303 (2021).

DOI: 10.1088/1361-6463/abde6a

The Poisson's ratios of graphene-copper nanolayered (GrCuNL) composites under tension and compression are investigated by molecular dynamics and theoretical analysis. The Poisson's ratio of a GrCuNL composite can be tuned by tailoring its repeat layer spacing without changing the topological structures. The effect of constituent nanocrystalline Cu grain size on the Poisson's ratio is negligible. There are remarkable in-plane anisotropy and tension-compression asymmetry in the Poisson's ratio due to the chiral difference in compressive stress in graphene layers. A mechanical model considering the chirality and repeat layer spacing is proposed, which can accurately predict the Poisson's ratio of a GrCuNL composite. For stable GrCuNL composites, the repeat layer spacing should be larger than 2 nm, and their tunable range of Poisson's ratio is 0.1-0.35.

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