Layer thickness dependent deformation mechanisms of graphene/high entropy alloy laminates upon nano-mechanical contact

Incorporating graphene into the CoCrFeNiMn high entropy alloy (HEA) significantly enhances the overall mechanical properties as have been verified experimentally. However, due to the limited technical analysis, the atomic-scale deformation mechanism of graphene interface has not been fully elucidated. In this work, molecular dynamics (MD) simulation is conducted to reveal the strengthening and plastic mechanism in CoCrFeNiMn HEA/graphene with a laminated structure. The weak interaction at graphene and HEA interface leads to a low shear resistance, which facilitates dislocation absorption. As a result, the competition mechanism between the “weakening effect” from the graphene/HEA interface and the “load-bearing capacity” from the graphene dominates the overall properties in graphene/high entropy alloy laminates. The size-dependent strengthening of the composite is therefore attributed to the crucial role played by the extent of graphene in bearing applied loads. These findings highlight the significance of graphene deformation for strengthening enhancement and providing guidance to design HEA composites.