Nanoscale bending properties of bio-inspired Ni-graphene nanocomposites

RR Santhapuram and SE Muller and AK Nair, COMPOSITE STRUCTURES, 220, 798-808 (2019).

DOI: 10.1016/j.compstruct.2019.03.093

At the nanoscale, bone consists of a hierarchical structure of mineral crystals (hard material) and collagen (soft material). Inspired by bone's nanoscale structure and properties, we design a nanocomposite with flexible pristine/polycrystalline graphene embedded in a hard Ni matrix. We model Ni graphene nanocomposites, with different structural arrangements for graphene in the Ni matrix. We use molecular dynamics to investigate the deformation of Ni-graphene nanocomposites under 3-point bending. We find that nanocomposites can deform approximately 30% more than pure Ni. The flexibility of the nanocomposite is optimally enhanced with a distance between graphene sheets greater than or equal to 3.05 nm. Polycrystalline graphene nanocomposites show approximately 15-20% improvement in bending modulus compared to pristine graphene nanocomposites. The increase in bending modulus of polycrystalline graphene nanocomposite is because polycrystalline graphene has higher interfacial shear strength compared to pristine graphene. We also find that the structural arrangement of graphene sheets is more important than increases in their volume fraction in the Ni matrix. These results suggest that graphene sheets scattered in the Ni-matrix is preferable to other structural arrangements. The results from this simulation could help in tuning nanocomposite with desired mechanical properties for various engineering applications.

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