Effect of Temperature on Strength and Residual Stress Distribution in Silicon Nitride to 304 Stainless Steel Brazed Joints

Abstract

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion and good corrosion properties. To combine the specific advantages of ceramics with that of metals, they are often used together within one composite component. In this study, the effect of temperature on fracture characteristics of silicon nitride joined to 304 stainless steel brazed with Ti active alloy are investigated in room and high temperature regions. And analytical studies on the residual stress of dissimilar brazed joint are performed by the finite element method. Four-point bending strength and deflection of interlayer increase with increasing strain rate in room temperature. As the test temperature increases, the bending strength decreases, but the deflection of interlayer is almost constant. The residual stresses redistribute after cutting of joint and the maximum tensile stress occurs on the new free surface at the ceramic near the interface. The singularity of residual stresses at the ceramic near the interface is characterized by elastic-plastic properties of ceramic and inserted materials.­