Powder-based numerical study of melt pool behaviors for Inconel 718 with TiC reinforcement using laser powder bed fusion process

Laser powder-bed fusion (LPBF) presents a promising alternative to fabricate metal matrix composites (MMCs). However, the melt behavior in MMCs, particularly those reinforced with ceramics, remains poorly understood. This study introduces a high-fidelity, powder-resolved simulation framework for LPBF of titanium carbide (TiC)-reinforced Inconel 718 (IN718), combining discrete element method and finite volume method to model powder spreading and laser-material interactions at the microscale. The simulation captures key melt pool phenomena and is validated using single-track experiments. Results reveal a nonlinear response in melt pool depth with increasing TiC content, with a 17 % decrease at 1 wt% TiC followed by a 26 % increase at 5 wt%. This result is attributed to competing effects of thermal diffusivity and laser absorptivity. In addition, while cooling rates vary with reinforcement contents, the dominant columnar grain growth mode remains unaffected. Furthermore, the predicted melt pool morphology correlates closely with experimental surface roughness (Ra) measurements, showing a significant reduction of ∼60 % in Ra from 9.3 to 3.8 µm at 5 wt% TiC. These findings deepen the understanding of MMC behavior in LPBF and demonstrate the predictive capability of powder-scale simulation framework for LPBF process optimization