Investigation of the tensor character of mesoscopic internal stresses in tensile-deformed nickel single crystals by X-ray diffraction Original Research Article

X-ray diffraction profiles of tensile-deformed nickel single crystals with two different orientations of the loading axis were investigated. To characterize the internal elastic strain state on a mesoscopic scale, the profile shapes of different Bragg reflections were analysed. The asymmetric profile broadening is interpreted on the basis of a two-component model for internal stresses in a dislocation cell structure. A least-squares method was applied to determine the stress tensor for the cell interior from the asymmetry parameters of at least six independent reflections. Furthermore, this method was advanced to evaluate the distribution of the plastic deformation across the slip systems. Taking into account an inclusion approximation, by this way the calculated internal stresses were correlated with the plastic strain in the cells. The orientation of the principal axes of the stress tensor and the heterogeneity of slip in the slip systems found agree with model assumptions for the tensile deformation.