Probing interface manipulation of metal-graphene composites via doping and vacancy engineering towards excellent mechanical strengths

Owing to the unique merits benefited from the two-dimensional (2D) geometry, graphene has been often chosen as an attractive strength enhancer during the design of metal-graphene structural composites. In spite of the improved mechanical properties with the assistance of graphene, it is still challenging to fit the strength requirements for these metal-graphene composites in the practical applications. To address this issue, metal-doping and carbon-vacancy engineering, in this work, are first proposed to manipulate the dual-phase interfaces between metal and graphene in order to further strengthen the mechanical properties in metal-graphene composites based on the first-principle calculation. It can be concluded that a single-carbon-vacancy graphene or a Ti, Mn-doped metal matrix in metal-graphene composites delivers the best interfacial binding capability, resulting in an obvious strength increase of over 110% for Cu-graphene composites. Finally, the deformation mechanisms of metal-graphene composites are discussed via the evaluation on tensile deformation processes, electron densities, and stacking fault energies. This work offers us an alternative solution for the effective reinforcement on mechanical properties of metal-graphene composites by manipulating the dual-phase interfaces using doping or vacancy engineering.