X-ray radiography techniques for analysing inhomogeneous stress conditions in ceramics, ceramic-to-metal joints, and thin films

The thesis was to solve problems encountered in the X-ray radiography analysis of inhomogeneous residual stress states and applied stress states in two-phase ceramics, hardened ceramic surfaces, thin surface coatings, and ceramic-to-metal joints brazed with active filler. In general, there are four different cases observed: 1. Inhomogeneous stresses in the microstructure of two-phase ceramics (microscopic stresses), 2. Residual, macroscopic stresses which are inhomogeneous within the range of wave penetration, as found in hardened ceramic surfaces, 3. systems of thin, fully radiation-exposed layers in which the residual stresses are assumed to be constant throughout the layer thickness, 4. thick layers with residual stress gradients which, however, are so flat that there is a quasi-homogeneous residual stress state in the surface layer exposed to the X-rays. The thesis explains the development and optimization of the various measuring and evaluation principles and instruments. The building up of residual stresses is discussed and their effects on the materials' or components' behaviour. (orig.)