Improving the graphene distribution and mechanical properties of graphene/Al composites by aminopropyl triethoxysilane modification

Uniform distribution of low-dimensional nano-carbon materials (NCMs) for the optimal enhancement effects is always a major issue of metal matrix composites (MMCs). In this study, aminopropyl triethoxysilane (APS) was introduced to synthesize Al@GO powders in an optimized process, by which, the uniform coating of GO on Al powders and the chemical bonding between them were obtained with the GO content up to 1.0 %. After hot pressed sintering using these powders, the GO/Al composite has a nacre-like structure that Al grains are lamellar with reduced graphene oxide (RGO) on the grain boundaries. By the application of APS with the optimized process, the relative density of 1.0 % RGO/Al composite increased from 99.2 % (without APS) to 99.7 % (with APS), indicating that the aggregation of RGO and the concomitant hole defects were effectively eliminated. Therefore, the average tensile strength of the 0.5 % and 1.0 % RGO/Al composites reached 243.6 MPa and 292.4 MPa, respectively, which were 105.9 % and 147.4 % improved compared with those of pure Al. This work has provided a new strategy to fabricate NCMs/Al composite with uniform dispersion of NCMs.