MAPPING OF THE RESIDUAL-STRESS DISTRIBUTION IN A BRAZED ZIRCONIA-IRONJOINT

Neutron diffraction was used to study the residual strain (stress) dis tribution in a zirconia-iron joint. The cylindrical specimen was obtai ned by brazing partially stabilized zirconia and cast iron disks sandw iched with a silver brazing alloy. The experimental data show that nea r the interface, the cast iron is mostly in tension while the zirconia is in compression, consistent with the thermal expansion mismatch bet ween the two materials. At a given radius, the measured strains vary r apidly as a function of distance from the interface. Along the radial direction, however, the strains are almost constant over half of the r adius. The experimentally determined residual strain distribution was compared with the results of a finite element analysis incorporating t he effects of plastic deformation. The favorable agreement between the experimental data and the finite element calculations indicates that the residual stress distribution in brazed ceramic-metal joints can be reasonably understood within the framework of an elastic-plastic fini te element model.