A method was proposed for computing virtual X-ray diffractograms, for nanocrystalline materials under a uniaxial load, based upon molecular-dynamics simulation data. While the increase in diffraction microstrain during deformation was generally taken as evidence for the generation of lattice dislocations, the present virtual diffraction data revealed extra microstrain even at small loads, before the onset of lattice dislocation activity. It was shown that the microstrain data had a natural explanation in the elastic response of a heterogeneous medium. The results implied that the conclusions of previous experimental in situ diffraction data for nanocrystalline metals may deserve a critical examination.

Microstrain in Nanocrystalline Solids under Load by Virtual Diffraction. J.Markmann, D.Bachurin, L.Shao, P.Gumbsch, J.Weissmülle: EPL, 2010, 89[6], 66002