Interfacial microstructure and mechanical properties of B ₄ C/TC4 brazed joints based on Ag–Cu–Ti + AlN/Mo foil/Nb foil

Abstract The bonding between titanium alloy (TC4) and B ₄ C ceramics was enhanced by employing a Mo foil/AgCuTi–AlN/Nb foil sandwich composite filler. The impact of varying AlN contents and brazing temperatures on the microstructure and mechanical attributes of the joints was explored. The joint strength was augmented through the utilization of AlN doping modification, which had a low expansion coefficient, and the plastic deformation of Mo and Nb foils. The findings revealed that AlN doping could refine the brazing organization of the joint, and the outstanding plasticity of Mo/Nb foils adapted to greater strain mismatches through elastic deformation. The most effective system emerged as nickel‐plated B ₄ C + Mo foil + AgCuTi–3 wt% AlN + Nb foil + TC4, which achieved the highest shear strength of approximately 109 MPa. This represents an enhancement of about 1.5 times compared to the shear strength of the system lacking additional brazing material.