Modelling Dislocation-Induced Anisotropic Line Broadening in Rietveld Refinements Using a Voigt Function. II. Application to Neutron Powder Diffraction Data

In paper I [Wu et al. (1998). J. Appl. Cryst. 31, 356–362] an approach was developed to the problem of modelling dislocation-induced X-ray or neutron-diffraction-line broadening. This paper applies those findings to the Rietveld refinement of the neutron powder diffraction profiles of deuterium-cycled LaNi₅ and β-PdD_0.66. These interstitially modified materials exhibit, respectively, strong and weak anisotropic strain broadening. The broadening in LaNi₅ is consistent with a dislocation slip system a/3 (110) {010}, in agreement with transmission electron microscopy studies. In PdD_0.66 the model predicts a regular distribution of screw dislocations, which remains to be confirmed by other techniques.