Dislocation effects in powder diffraction

Owing to the lack of proper models, mainly for the strain broadening component due to dislocations, full exploitation of whole powder pattern modelling for the microstructural analysis of materials has been limited so far to high-symmetry lattices. An extension of the dislocation-induced broadening model, valid for any lattice symmetry, is proposed here. Dislocation effects are modelled through the description of the dislocation contrast factor in terms of a crystallographic invariant whose terms can be either calculated when the material constants and slip systems are known (allowing a dislocation density to be refined) or refined on the experimental data for an effective estimation of dislocation effects.