Affiliation:
1. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China
Abstract
The microstructure and formation mechanism of the boron carbide (B4C) and titanium alloy (TC4) joints brazed with AgCuTi-AlN-W + Mo foil + Nb foil brazing filler were investigated. The effects of W/AlN content on microstructure and mechanical properties of the joints were discussed. To alleviate residual thermal stress, refractory metal foils such as Mo/Nb foils were added. Compared with the common composite interlayers, the interlayer formed via AgCuTi-AlN-W + Mo foil + Nb foil in-situ alloying had more and finer reinforcing phases without reducing the activity of the filler material. The ductile Mo/Nb foils contributed to accommodate the large strain mismatch by elastic deformation. The interfaces between the adjoining materials and the interlayer were well-bonded without any cracks. The most effective system was nickel-plated B4C + Mo foil + AgCuTi-3 wt% AlN-5 wt% W + AgCu foil + Nb foil + TC4, which exhibited the highest shear strength of approximately 115 MPa.