Effect of Processing Techniques on Interface Bonding of Graphene Reinforced Metal Matrix Composites: A Review

Graphene (Gr) and its derivatives [such as reduced graphene oxide (RGO), graphene oxide (GO), etc.] have unique material characteristics, such as large surface area, high tensile strength and high thermal conductivity, and thus are competitive candidates for reinforcing metal matrix composites (MMCs). However, integrating Gr into MMCs is challenging—not only the inhomogeneity of Gr dispersion, but also the poor wettability in the interface between Gr and MMCs. During the last decade, Gr-reinforced MMCs (Gr-MMCs) with excellent mechanical performance have been made by various synthesis methods. The improved functionalities are ascribed to higher interface strength. To understand the reinforcement principles, it is indispensable to explore the relationship between the synthesis methods and interface. This article focuses on the preparation technologies of the well-bonded interface, including the modification strategies for Gr, pretreatment for MMCs and combination of the two parts to provide a deep horizontal comparison of fabrications of well-bonded interfaces, thereby solving the problems of combining Gr and MMCs for future researchers. Besides, various strengthening mechanisms are explored to explain how the microstructure, degree of reinforcement dispersion and extent of interfacial reaction affect the strengthening efficiency. Finally, the future research directions for Gr-MMCs are outlined.