Williamson–Hall anisotropy in nanocrystalline metals: X-ray diffraction experiments and atomistic simulations

X-ray diffraction techniques allow the determination of mean grain size, root-mean-square strain and dislocation/twin content through peak profile analysis and the Williamson–Hall approach. The analysis is, however, based on assumptions that are questionable when applied to nanocrystalline (nc) structures. In the present work, two-theta X-ray diffraction profiles are calculated from multi-million atom computer-generated nc-Al samples containing a well-defined twin or dislocation content. The Williamson–Hall plots are compared with those obtained from in situ X-ray experiments performed on electrodeposited nc-Ni and on nc-Cu data available in the literature.