Microstructural and mechanical properties of reaction-bonded silicon carbide (RBSiC) brazed with Si-Ti eutectic alloy

The self-joining of Reaction-Bonded Silicon Carbide (RBSiC) was achieved using a Si-Ti eutectic alloy via vacuum brazing, offering a novel approach for high-performance SiC component integration. This study provides a comprehensive investigation into the wetting behavior of the Si-Ti eutectic on RBSiC, coupled with a detailed analysis of how brazing temperature influences joint microstructure, mechanical properties, and fracture morphology. The Si-Ti eutectic alloy exhibits an exceptionally low contact angle of 15° on the RBSiC surface, indicating superior wettability and spreading characteristics critical for robust bonding. The joints were primarily formed through atomic-scale interactions, with no new intermetallic compounds generated, ensuring the long-term stability of the interface. Brazing at 1375 °C for 15 min resulted in a shear strength of 154 MPa, with fracture occurring at the substrate, highlighting the excellent mechanical properties of the joints. The evolution of the joint microstructure and the underlying strengthening mechanisms were elucidated, providing insights into the intrinsic behavior of the bonding process. This pressureless joining technique paves the way for broader applications of high-performance SiC components, particularly in industries demanding advanced material integrity and reliability.