Interfacial engineering for enhanced heat transport: brazing femtosecond-laser-treated SiC to 3D-printed SiC-reinforced Ti6Al4V composites

With the growing demand for high-performance thermal management devices, achieving efficient and reliable joining between 3D-printed SiC-reinforced Ti6Al4V composite (3DP-SiC/TC4) and SiC ceramic presents a critical challenge. To enhance the interfacial thermal conductivity, femtosecond laser treatment (FLT) was applied to the SiC ceramic, aiming to construct a uniform striated microstructure. AgCuTi braze was employed to join 3DP-SiC/TC4 with femtosecond laser-treated SiC ceramic (FLT-SiC). The interfacial reaction mechanisms, microstructural evolution, and thermomechanical property optimization were systematically investigated. Based on a series-parallel thermal resistance model, it was revealed that the FLT significantly reduce interfacial thermal resistance by increasing the effective contact area and promoting metallurgical joining. The FLT influences the synergistic effect between geometric morphology and chemical joining. At 0.63 W, a positive synergy between geometric (gain factor ξ geo = 1.083) and interfacial chemical ( κ chem = 1.087) contributions was achieved. The brazing temperature regulated the extent of interfacial reactions, with 850 ℃ yielding a dense microstructure and optimal properties. The optimal parameters were identified as a laser fluence of 0.63 J/cm 2 and a brazing condition of 850 ℃ for 10 min. Under these conditions, the joint exhibited a shear strength of 46.5 ± 2.4 MPa and a thermal conductivity of 24.6 W·m -1 ·K -1 at 600 ℃. This study provides a novel approach for joining dissimilar materials in thermal management applications, leading to a significant enhancement in the thermal and mechanical performance of the joint.