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A correct interpretation of the diffraction phenomenon in crystals with low dislocation content, for which the kinematical scattering theory does not yield any reasonable results, was carried out by X-ray extinction treatments. Different approaches to investigating the dislocation-induced X-ray extinction changes are reviewed and the applicability of the statistical dynamical theory to analysis of the substructure characteristics of crystals is discussed. A relationship between the scattering amplitudes and the dislocation density in crystals is established by using pair correlation functions. A procedure for determination of the substructure characteristics by means of measurements of the integrated intensities is proposed. The tests illustrate satisfactory agreement of the investigated approaches with experimental data. [ABSTRACT FROM AUTHOR]

The correct description of the mechanical behaviour of metallic materials after deformation to large strains requires the quantitative determination of substructure characteristics on different length scales. Important tools for this purpose are transmission electron microscopy (TEM), electron backscattering diffraction (EBSD) and X-ray diffraction (XRD), which lead to quantities such as the mean total dislocation density, the density of excess dislocations stored in dislocation walls, the distributions and the averages of local lattice rotations and the size (chord length) of the lattice regions (cell blocks, fragments) of the mesoscale substructure. This present paper illustrates the application of EBSD and XRD for the analysis of the deformation substructure occurring in polycrystalline Al during uniaxial compression up to strains ε ≈ 2. [ABSTRACT FROM AUTHOR]