Integral method of preparation and fabrication of metal matrix composite: Selective laser melting of in-situ nano/submicro-sized carbides reinforced iron matrix composites

This paper presents a study on the formation, microstructure and mechanical property of Cr3C2/Fe nanocomposites using selective laser melting (SLM). Scanning electron microscope (SEM), transmission electron microscope (TEM) and tensile tests were conducted to investigate the influence of Cr3C2 particulates on the microstructure and mechanical properties. It was found that the porosity decreased when volumetric energy density increased from 27 to 37 J/mm3, then rose to 55 J/mm3. The results showed that the Cr3C2 particulates decomposed completely during SLM process and interacted with Fe matrix to form (α-Fe, Cr) solid solution and M(Fe, Cr)23C6 carbides. In addition, due to the characteristic of rapid solidification, very fine grains were obtained throughout the composites. The tensile tests showed that the ultimate tensile strength could reach up to 1158 MPa.