Microstructure, mechanical properties and corrosion performance of selective laser melting Ti/GNPs composite with a porous structure

In this study, nano-graphene reinforced titanium matrix composites (GNPs/Ti) with a honeycomb porous structure were fabricated by selective laser melting (SLM). The effects of graphene on the microstructure, mechanical properties and corrosion performance of the SLM GNPs/Ti were systematically investigated. Results of microstructure characterization show that: 1) the density of the SLM GNPs/Ti was improved as compared to that of the SLM Ti; 2) abundant TiC particles were formed in the SLM GNPs/Ti. The hardness and compressive strength of the composite increased by 90% (from HV 236 to HV 503) and 14% (from 277 MPa to 316 MPa), respectively, attributed to the uniformly distributed TiC and fine GNPs in the Ti matrix. Electrochemical tests reveal that the corrosion current density of the SLM GNPs/Ti is only 0.328 μA/cm2, that is about 25% less than that of the SLM Ti. The results indicate that the incorporation of nano-graphene is a potential method to strengthen the Ti by SLM.