Residual Stresses in Ceramic-Interlayer-Metal Joints

Thermal residual stresses due to the thermal expansion mismatch in a ceramic–interlayer–metal joint are calculated analytically. A qualitative estimate of the stress distribution is obtained by assuming the joint consists of one or two elastic slabs sandwiched between two semi‐infinite isotropic elastic solids. These elastic solids and the interlayer(s) are perfectly bonded to each other at the planar interfaces. The region where temperature change takes place is assumed to be a cylinder with its axis normal to the interface. A simple equation is obtained for the stress value at the center of the ceramic‐interlayer interface as a function of the thermal expansion coefficients, elastic constants of the constituent materials, and the thickness of the interlayer(s). The results obtained by this simple model agree well, qualitatively, with those obtained experimentally and numerically (finite element calculations). An appropriate interlayer material to reduce the residual stress in ceramic‐metal joints is suggested.