Strain fields in crystalline solids: prediction and measurement of X- ray diffraction patterns and electron diffraction-contrast images

Lattice imperfections, such as dislocations and misfitting particles, shift and/or broaden X-ray diffraction (XRD) line profiles. Most of the present analysis methods of the shift and broadening of XRD line profiles do not provide the characteristics of lattice imperfections. The main part of this thesis deals with a new approach to the analysis of broadened and shifted XRD line profiles that does not have the limitations of the present analysis methods. The approach is based on micromechanical modelling of the microstructure of the material. A small volume which is representative of the microstructure of the material is used to model and calculate the materials behaviour on a local scale incorporating the (strain fields of the) lattice imperfections. Subsequently, the behaviour of this representative element can be used to calculate the overall materials properties. X-ray diffraction-line profiles are calculated from such model materials and are compared with the measured ones. By adjusting the parameters of the micromechanical model, the calculated line profiles can be matched to the experimental ones. In this way characteristics of the microstructure of the experimental material can be determined and subsequently overall materials properties can be predicted. Hence, a direct link between XRD line-profiles characteristics and materials properties is conceivable.