Enhancing mechanical properties of Al matrix composites via porous reduced graphene oxide strengthened interface

Abstract

Defective graphene can effectively improve the interface between graphene and Al matrix. To further improve the interface bonding between graphene reinforcement and Al matrix, chemical etching was proposed to generate nanopore defects on surface of graphene oxide (GO), forming porous reduced graphene oxide (P-RGO) reinforcement. P-RGO/Al hierarchical composites were prepared by electrostatic adsorption, ball milling, and spark plasma sintering. "P-RGO rich zones" were formed via uniformly distributing P-RGO into Al matrix, and thus a hierarchical structure consisting of "P-RGO rich zones" and "P-RGO free zones" was constructed. The results show that ultimate tensile strength (UTS, 339.8 MPa), yield strength (YS, 296.1 MPa), and elongation (εf, 9.1 %) of P-RGO/Al hierarchical composites were 23.1 %, 78.1 %, and 9.6 % higher than those of GO/Al composites. Nanopore defects increased specific surface area of P-RGO and provided nucleation sites for the interfacial reaction. Al2O3 formed in situ at the nanopores and Al12Mg17 precipitated at the interface together improved the interfacial bonding and enhanced the load transfer. The hierarchical configuration established by "P-RGO rich zones" and "P-RGO free zones" arranged alternately in space promotes crack deflection and increases crack propagation path. This work provides a promising way for the fabrication of high-performance composites.