Insight into interfacial microstructural evolution and mechanical properties of B₄C-TiB₂/TA15 dissimilar joints brazed by AgCu filler

B₄C TiB₂ multiphase ceramics and TA15 titanium alloy possess outstanding comprehensive performance, which makes the reliable joining of these two materials highly valuable for advanced structural applications. In this study, B₄C-TiB₂ ceramics and TA15 alloy were successfully brazed using an AgCu filler. The effects of brazing temperature on the interfacial microstructures and mechanical properties of the brazed joints were systematically investigated. TEM characterization revealed that a reaction layer composed of TiB and TiC was formed at the B₄C-TiB₂ interface, and the interfacial reaction mechanism was thermodynamically analyzed. The typical interfacial structure of the sound joint can be described as: B₄C-TiB₂/ TiB+ TiC/ Cu(s,s)+ Ag(s,s)/ TiAlCu₂+ Ti₂Cu₃+ TiCu+ Ti₂Cu/ β-Ti+ α-Ti/ TA15. With the increase of brazing temperature, the reaction layers near TA15 gradually thickened, and β-Ti enriched zone was obviously broadened. Meanwhile, the (TiB+ TiC) reaction layer at the B₄C-TiB₂ side interface increased. The shear strength of the brazed joints first increased and then decreased with rising brazing temperature. The maximum average tensile strength is 67.58 MPa, corresponding to a brazing temperature of 880 °C and a holding time of 10 min. Fracture observations indicated that the joints mainly failed near the B₄C-TiB₂ interface. This work provides an effective and feasible method for brazing B₄C-TiB₂ multiphase ceramics to TA15 titanium alloy, and supports the engineering application of ceramic-metal hybrid components.