FINITE-ELEMENT SIMULATION OF THERMAL RESIDUAL-STRESSES IN JOINING CERAMICS WITH THIN METAL INTERLAYERS

Finite element analysis was used to estimate thermal residual stresses developed in silicon nitride bodies bonded by metallic interlayers, S tresses mere calculated for various characteristic metals, namely, Ni, Al, and Si, assuming elastic and elastic-plastic behavior. The relati ve importance of the metal properties, such as thermal expansion coeff icient, stiffness and ductility, has been evaluated. Two different joi nt geometries, butt and lap, have been used in stress calculations, an d special care was taken in the mesh generation, to obtain comparable results, The yield stress of the interlayer material rather than therm al expansion mismatch Ts the critical factor in thermal residual tensi le stress buildup inside ceramic adherents.