Performance of 3D-printed SiC-reinforced Ti6Al4V and its high thermal conductivity brazing with SiC ceramics

The development of efficient thermal management systems urgently requires reliable joining between 3D-printed SiC-reinforced Ti6Al4V composites (3DP-SiC/TC4) and SiC ceramics. This study comprehensively investigates the microstructure, physical properties and wettability of 3DP-SiC/TC4 fabricated by electron beam melting (EBM). Compared with original TC4, 3DP-SiC/TC4 exhibits a lower coefficient of thermal expansion (8.4 × 10⁻⁶·K⁻¹) and a higher thermal conductivity (11.647 W·m⁻¹·K⁻¹). High-quality brazed joints are achieved between 3DP-SiC/TC4 and SiC ceramics using AgCuTi braze. Microstructural evolution, mechanical properties and thermal characteristics are systematically investigated. A layered reaction zone preferentially forms at SiC interfaces, consisting of TiC and Ti₅Si₃ with a total thickness of ∼ 1.0 μm. The central region of the joint develops a mixed microstructure of Ag(s,s) and Ti-Cu intermetallic compounds, while graded Ti-Cu diffusion zones form on the 3DP-SiC/TC4 side. The heat transfer analysis demonstrates that brazing effectively reduces the interfacial thermal resistance by filling the air gaps. The optimal brazing temperature is 850 °C, achieving joints with the shear strength of 39.5 ± 1.0 MPa and the thermal conductivity of 21.6 W·m⁻¹·K⁻¹ (tested at 600 °C), representing 57% and 56% improvements over original TC4 joints respectively. This research provides innovative material joining solutions for lightweight aerospace thermal management system design.