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 Cr 3 C 2 /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 Cr 3 C 2 particulates on the microstructure and mechanical properties. It was found that the porosity decreased when volumetric energy density increased from 27 to 37 J/mm 3 , then rose to 55 J/mm 3 . The results showed that the Cr 3 C 2 particulates decomposed completely during SLM process and interacted with Fe matrix to form (α-Fe, Cr) solid solution and M(Fe, Cr) 23 C 6 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. [ABSTRACT FROM AUTHOR]