Simultaneously enhanced strength-plasticity of graphene/metal nanocomposites via interfacial microstructure regulation

Interfacial microstructure characteristics (e.g., volume fraction, thickness, moduli) are crucial to the overall mechanical properties of graphene/metal nanocomposites. Herein, we investigate the effects of different interfacial characteristics on simultaneous improvement of strength and plasticity of nanocomposites. Graphene nanoplatelets (GNPs) reinforced Ti6Al4V composites with appropriate interfacial effects are first fabricated based on powder metallurgy. Combining the interphase model, the field fluctuation method, the second-order stress moment and continuous damage theory, the multiscale theoretical framework for predicting the entire stress-strain relations is developed, and its accuracy is verified by the tensile test results of GNP/Ti6Al4V nanocomposites. The effects of the micromechanical variables including volume fraction and stiffness of interphase, as well as geometrical size factor (ratio of interphase thickness to the GNP equivalent diameter) and aspect ratio of GNPs on the maximum strength and failure strain are quantitatively analyzed to demonstrate how the strength and plasticity of nanocomposites are enhanced concurrently. This work provides a new perspective for graphene/metal nanocomposites with excellent tensile properties by optimizing interfacial characteristics.