The X-ray diffraction powder patterns of a random nanocrystalline material which comprised 2 atomic species were calculated by evaluating the Debye function. Atoms of various types were positioned so as to model a stoichiometric compound, CsCl, or grain-boundary segregation in Cu-Fe alloys. Radial strain fields of the type that were associated with point or boundary defects were introduced into the structure, and the X-ray powder patterns were calculated. Grain boundary defects which had a different composition to that of the bulk were introduced and were combined with radial strain fields. The diffraction signatures of so-called gas-like and crystalline grain boundaries were calculated and compared.

J.S.Lee, R.J.De Angelis: Nanostructured Materials, 1996, 7[7], 805-12