Impact of in-situ/ex-situ TiC-reinforcement in Ti composite manufactured by PBF-LB

Titanium-based metal-matrix composites manufactured by additive manufacturing offer tremendous lightweighting opportunities. However, processing high reinforcement content remains challenging, and damage accumulation negates reinforcement as strain increases. This study reports an improved manufacturing process for Ti-TiC, enabling high reinforcement content, significant fracture strain, and drastically reduced damage accumulation. Ti-TiC samples were produced from different types of TiC powder as well as in-situ from the reaction of Ti and C. Microstructure, mechanical properties, and damage accumulation were characterised in each case. The presence of defects in the feedstock powder was shown to increase damage accumulation. Comminuted particles gave the best results between the different TiC powders, and in-situ produced TiC gave the overall best result. We report a decrease of >90% in damage accumulation between aggregated TiC and in-situ TiC. The Ti-TiC samples displayed a Young’s modulus increase of >30%, reaching close to 150 GPa while keeping fracture strain above 3%.