Bulk titanium–graphene nanocomposites fabricated by selective laser melting

In this report, bulk graphene–reinforced titanium (Ti–Gr) nanocomposite with millimeter thickness was fabricated by selective laser melting process. Demonstrated by the characterizations of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectra, graphene nanoplatelets were successfully embedded into the titanium matrix with a uniform dispersion due to a fast heating–cooling process. High-resolution transmission electron microscopy was used to investigate the interface between titanium and graphene, where a certain amount of carbide was formed attribute to the chemical reaction between them during multilayer laser melting. A high density of dislocations was observed surrounding the graphene nanoplatelets in titanium matrix. The strength and elastic modulus of the nanocomposites were significantly improved, which has been demonstrated by nano-indentation tests. The hardness of the bulk Ti–Gr nanocomposites was approximately 1.27 times higher than pristine Ti counterpart. The strengthening mechanisms were discussed in detail.