Non-Destructive Analysis of Surface Stresses Using Grazing Incident X-Ray Diffraction

The X-ray diffraction measurements based on the grazing incident geometry were applied to determine lattice strains in polycrystalline materials. This method enables a non-destructive measurement at chosen depth below the sample surface. The volume, for which the stress is measured, is well defined and it does not vary during experiment. The multireflection method was used for analysis of the experimental results since the interplanar spacings were measured for various orientation of the scattering vector as well as for various crystallographic planes {hkl}. Applying two different wavelengths of X- ray radiation and various incident angles non-destructive measurements of the residual stresses in function of penetration depth were performed. The variation of stresses in plastically deformed surface layers of steel samples was successfully determined and the values of the stresses were confirmed by standard diffraction measurement.