Formation mechanism and phase evolution of in situ synthesizing TiC-reinforced 316L stainless steel matrix composites by laser melting deposition

•A novel method “in situ synthesis” based on additive manufacturing was proposed.•The mechanism of TiC formation has been explored based on thermodynamics.•The phase transformation mechanism from γ-Fe to α-Fe phase was investigated.•The grain texture of the γ-Fe matrix was investigated. Different weight ratios of 316L austenitic stainless steel, Cr3C2 and Ti powders were mixed to synthesize TiC-reinforced Fe-based composites by laser melting deposition. Fine TiC-particles were in situ synthesized through the reaction of Ti with Cr3C2 and were found to be uniformly dispersed in the matrix. The α-Fe phase was precipitated out of the γ-Fe matrix with the addition of Cr3C2 and Ti powders. The mechanism of TiC formation and phase evolution was analyzed based on thermodynamics calculations. The volume fraction and the size of the in situ synthesized TiC were found to affect grain texture of the γ-Fe matrix.