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Determination of displacements from nanoprecipitates in a Cu–Ni–Fe single crystal using anomalous small‐angle and large‐angle X‐ray scattering
Author(s) -
Lyon O.,
Guillon I.,
Servant C.
Publication year - 2001
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889801008809
Subject(s) - scattering , small angle x ray scattering , materials science , wide angle x ray scattering , small angle scattering , crystallography , single crystal , lattice (music) , bragg's law , anomalous scattering , condensed matter physics , diffraction , small angle neutron scattering , optics , chemistry , neutron scattering , physics , acoustics
Single crystals of Cu–41.5 at.% Ni–16 at.% Fe have been studied by small‐angle and large‐angle X‐ray scattering in order to determine the displacements induced by the disc‐like precipitates formed during decomposition. The small‐angle X‐ray scattering (SAXS) patterns gave information on the size and the organization of the precipitates, while the scattering near Bragg peaks allows a determination of the distortions of the lattice created by these precipitates. The variations of the atomic scattering factors of Fe, Ni and Cu (for the large‐angle measurements) were used to determine both the partial structure functions (`chemical' data) and the partial displacements. The precipitates were found to be enriched in Fe and Ni, which induced a contraction of the lattice, while the depleted matrix (mainly Cu) was dilated. This succession of compressed and dilated regions is very stable and prevents a single precipitate from growing much in this direction during coarsening. This can explain why a single precipitate tends to grow mainly in the orthogonal directions, where the extension of the displacements is smaller than the precipitated region.