Estimation of Strength Reliability for Ceramic/Metal Jointing Structure -The Basic Study of Thermal Stress and Residual Stress Behavior during Ceramic/Metal Joint process

摘要

A simple analysis method was developed bymaking well use of finite element method (FEM) program forgeneral purposes. The temperature dependence of mechanicalproperties for every material consisting of ceramic/metaljointing was considered in this method. Using this method, theresidual stresses producing during the jointing process wereanalyzed for Si_3N_4/SUS304 joints with the insert layer of Cumade by an active metal brazing (Ti-Ag-Cu) method so as toclarify the residual stress behavior due to the creep of Cu. Theequivalent normal stress calculated from the multi-axial stresseswas used to evaluate the strength of fracture which resulted frominitial flaws existing in the ceramic side. From the analyticalresults, it is found that the temperature at which the residualstress begins to generate is about 550 deg C, and it is clarifiedthat the creep of Cu layer during cooling process may relax theresidual stress in ceramics side and can not be neglected for theestimation of ceramic fracture due to residual stress.