3D printing graphene-aluminum nanocomposites

This report studies the microstructure and property of graphene reinforced aluminum matrix composites (Gr-Al) as fabricated by laser 3D printing. Recently, 3D printing was under extensive exploration, while graphene has been considered as one of the most promising reinforcement fillers for metal matrix composites (MMCs) due to its mechanical robustness. Thus, it is of great importance to assess the efficacy of using 3D printing to fabricate the graphene reinforced MMCs. Herein, the mixture of graphene and aluminum powders was prepared by ball milling with various graphene weight ratios, and then sintered by the selective laser melting to fabricate bulk Gr-Al composites. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), and Raman spectroscopy were used to characterize the microstructures and components of the nanocomposites. The surface and cross-sectional SEM images, XRD patterns, and Raman spectrum verified not only the survival but also the distribution of graphene in Gr-Al composites. High resolution TEM (HRTEM) images further revealed the co-existence of aluminum, graphene and aluminum carbide. The Vickers hardness and nano-indentation tests showed the hardness of the composites was greatly enhanced. Compared with pure aluminum counterpart, the Vickers hardness of the best composite sample achieves a 75.3% increase. All the experimental results suggest the efficacy of laser 3D printing technology to fabricate Gr-Al composites.