Additive manufacturing of graphene reinforced 316L stainless steel composites with tailored microstructure and mechanical properties

Since its inception, additive manufacturing has facilitated the processing of novel metal matrix composites that are challenging to fabricate using conventional manufacturing methods. The laser-based additive manufacturing process is a promising technology to fabricate uniformly dispersed graphene-reinforced stainless steel nano -composite. In this study, the effect of energy density modulation on densification, microstructure, and me-chanical properties of (316L) stainless steel reinforced with 0.2 wt% multi-layered graphene nanosheets was investigated. The highest relative densification (94.7% +/- 0.5) has been achieved at the volumetric energy density of 240 J/mm3. The formation of dislocation cells, inclusions and graphene-steel interaction have been identified in the microscopic analysis. Addition of graphene as reinforcement and nano-inclusions formed (in situ) during solidification promotes the pinning of dislocations around the cellular sub-grains. Alteration of volumetric energy density is an essential technique to tune the texture and microstructure of the additively manufactured samples. As the volumetric energy density increased to 240 J/mm3, the tensile strength achieved is around 1165 +/- 5 MPa.