Microstructural and mechanical properties evaluation of graphene reinforced stainless steel composite produced via selective laser melting

Abstract Graphene (Gr)-reinforced 316L stainless steel (Gr/SS 316L) composite was fabricated through the selective laser melting (SLM) technique to avoid the agglomeration of graphene and develop a composite that has higher specific strength. Here, 316L stainless steel and graphene powder was first mixed using ball milling. The formed mixture was then used as raw powder for the SLM system. The fabricated composite underwent hardness and tensile tests. The obtained results reveal that the properties of the composite significantly improve with the addition of 0.2 wt% Gr. The hardness and yield strength of the composite increased by up to 25% (from 194 to 245 HV) and 70% (from 502 to 850 MPa), respectively. Experimental values were also compared with the theoretically calculated results, and the possible reasons behind the variation in both values were discussed. A micrograph and electron backscatter diffraction map of the composite was analysed under a field-emission scanning electron microscope to determine the microstructure and grain orientation. Raman mapping and X-ray diffraction were performed to analyse the distribution of Gr in the matrix and its effect on the formation of carbide, respectively. Finally, the SLM technique was found to be a practical method for synthesising Gr/SS 316L composites with superior mechanical properties.