The strengthening mechanism of mechanical and tribological properties of TiC-reinforced 316L matrix composites fabricated by selective laser melting

Selective laser melting (SLM) has been proved to be a promising additive manufacturing technique to fabricate high-performance metal matrix composites (MMCs) with unique microstructures. In this study, TiC-reinforced 316 L MMCs were successfully prepared by SLM. The effects of TiC addition on the microstructure evolution, mechanical properties and tribological behavior were systematically investigated to study the strengthening mechanism. The TiC/316 L MMCs fabricated by SLM exhibited a high relative density of over 99.6% and were close to full density. The TiC particles are effectively bonded with the 316 L matrix, serving as a means of dispersion strengthening. In addition, the grains were significantly refined, and the dislocation density was greatly enhanced with the addition of TiC particles, which reinforce the strength of the material. Tensile tests show that the tensile strength of TiC/316 L MMCs increased by 49.9% from 707 to 1060 MPa and yield strength increased by 44.2% from 543 to 783 MPa with 4 wt.% TiC. Besides, the tribological behavior of TiC/316 L MMCs was much superior to the pure 316 L. The findings provide a new perspective on ceramic particles reinforced stainless steel MMCs with tailored microstructure and excellence performance.