A new method for preparing high-strength and thermally-resistant ceramic/metal brazed joint at low temperature

Abstract

AgCu+TiH2+Nb filler was newly-designed to braze Ti2AlNb and SiBCN. The Ag–Cu melt firstly filled the interfacial gaps and then solidified into refractory Ag(s,s) via Ti–Cu interaction, while Nb refined the brittle compounds and relieved the residual stresses well. The obtained joint exhibited a shear strength of 73 ± 10.2 MPa and 81.7 ± 9.5 MPa at room temperature and 600 °C respectively, which is 3.1 and 1.7 times of that with AgCu. No softening occurred at 600 °C and the strength remained 24 ± 1.4 MPa at 800 °C. The proposed method provides a new strategy for preparing high-temperature joint at low temperature, to address the issues of poor thermal resistance as well as huge residual stresses and excessive formation of brittle phases.

Keywords

• Composite brazing
• Ti2AlNb
• SiBCN
• Thermal resistance
• Residual stresses