A STUDY OF X-RAY RESIDUAL-STRESS GRADIENT ANALYSIS IN THIN-LAYERS WITH STRONG FIBER TEXTURE - II - EXAMPLES

The mechanical properties of thin hard coatings like resistance to abr asive wear are known to depend strongly on the texture as well as on t he distribution of the residual stresses over the layer thickness. The analysis of these stresses in thin coatings by means of X-ray diffrac tion, however, is rather difficult because the diffraction volume rema ins small in many cases and the stress fields are often superimposed b y gradients of the texture and/or the chemical composition. By the exa mple of PVD Ti1-xCrxN coatings with pronounced (111) fibre texture, we compare several methods in X-ray stress analysis with respect to thei r suitability for the detection of non-uniform residual stress distrib utions. The best results are obtained by means of the scattering vecto r method, where the depth profiles of the lattice spacings, d(phi psi) (hkl,tau), are measured at fixed positions (phi,psi) with respect to t he sample reference system after stepwise rotation of the sample aroun d the scattering vector g(phi psi).