Microstructure and tensile properties of TiC/316L composites fabricated by laser metal deposition

Laser Metal Deposition（LMD） technology allows for simultaneous powder delivery and focused laser energy application, resulting in high material forming efficiency. This approach enhances material properties,reduces manufacturing costs, and shows wide application prospects. TiC/316L stainless steel composites with reinforcement contents of 0%, 0.5%, 1%, and 2% were fabricated using LMD technology to investigate the effects of reinforcement content on the microstructure and mechanical properties. Metallographic analysis revealed a fishscale morphology in the melt pool. Equiaxed grains dominated the central region, while columnar grains were prevalent at the edges. Columnar grains between adjacent melt pools exhibited epitaxial growth, with equiaxed grain sizes ranging from 10μm to 50μm, and most columnar grains exceeding 100μm. With increasing TiC content, the tensile strength of the composites improved significantly. At 1% TiC, the tensile strength rose from 623MPa to 679MPa,maintaining an elongation of 30.42%. However, at 2% TiC, the elongation dropped to 5.1%, with agglomeration of TiC particles observed in the microstructure.