Atomistic interpretation of microstrain in diffraction line profile analysis

A virtual X-ray powder diffraction experiment is conducted on a realistic computer-generated nano-polycrystalline microstructure. It is shown that the size and strain broadening contributions to the diffraction line profiles can be directly and reliably extracted from the atomistic model. It is also shown that current line profile analysis methods cannot fully interpret the observed patterns due to the peculiar microstructure of grain boundaries.

► A nano-polycrystalline microstructure is modelled by molecular dynamics.
► The local isotropic and anisotropic deformation fields are characterised.
► Frequency distribution of the atomic pair distances along directions are computed.
► X-ray diffraction spectra simulated via Debye and Fourier approaches are compared.