Finite-element analysis and X-ray measurement of the residual stresses of ceramic/metal joints

The residual-stress distribution of ceramic/metal joints was measured using the X-ray diffraction method, and the indentation fracture method, and was also calculated using the finite-element method. The greatest residual tensile stress is found to occur at the ceramic side near to the interface, for all the methods. The relaxation of the residual-stress distribution after the mechanical load cycles was evaluated using the X-ray method. The effect of interlayer thickness and compressive load during the joining process were also studied for an S45C/Si3N4/S45C round specimen. Four-point bending tests were conducted for Si3N4/S45C and S45C/Si3N4/S45C round specimens. It was found that the crack path depends significantly on the bending strength. The crack path can be explained by introducing Dunders parameter beta and the mode I stress intensity factor of an edge crack. (C) 1997 Elsevier Science S.B.