Dislocation structure and crystallite size-distribution in hexagonal nanomaterials from X-ray peak profile analysis

The microstructure of three different nanocrystalline materials with hexagonal crystal structure are studied by X-ray diffraction peak profile analysis. The crystallite size distribution and the dislocation structure are determined in plasmathermal silicon nitride powder, sintered tungsten carbide and severely deformed titanium and are compared with transmission electron microscopy (TEM) results. In the case of the silicon nitride powder the particle size determined by TEM is in good correlation with the coherently scattering domain size provided by X-rays. In the case of bulk titanium the crystallite size given by X-rays correlates well with the dislocation cell size obtained by TEM. It is found that in tungsten carbide the dominant dislocation slip system is basal, whereas, in plastically deformed titanium the basal slip is practically absent with the dominance of pyramidal dislocations in good correlation with other investigations of the literature.