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 ill the literature. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.