Effect of Mo addition on residual stress and mechanical properties of SiC ceramic/Nb521 alloy joints brazed by using AgCuTi filler

Abstract

Residual stress has great influence on the mechanical properties of ceramic/metal joints. In the study, SiC ceramic and Nb521 alloy were vacuum brazed by using AgCuTi filler, and Mo particles were added into the filler to reduce the residual stress of joint. The effects of Mo content on the microstructure and mechanical properties of the joints were systematically investigated. The addition of Mo effectively controlled the thickness of TiC + Ti5Si3 reaction layer nearby SiC ceramic. The suitable thickness of TiC + Ti5Si3 reaction layer could improve joint strength. The addition of Mo particles could also reduce the coefficient of thermal expansion (CTE) mismatch between base materials and filler. The shear strength reached 78.5 MPa with AgCuTi + 5 wt% Mo filler, which was 118% higher than the joint brazed with pure AgCuTi filler.