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Atomistic origin of microstrain broadening in diffraction data of nanocrystalline solids

Stukowski, A. ; Markmann, J. ; Weissmueller, J. ; Albe, K. (2009)
Atomistic origin of microstrain broadening in diffraction data of nanocrystalline solids.
In: Acta Materialia, 57 (5)
doi: 10.1016/j.actamat.2008.12.01
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

The origin of microstrain broadening in X-ray diffraction patterns of nanocrystalline metals is investigated by comparing data obtained from Virtual diffractograms and from direct analysis of computer-generated samples. A new method is introduced that allows the local deformation gradient to be calculated for each lattice site in the microstructure from atomic coordinates obtained by molecular dynamics simulations. Our results reveal that microstrain broadening in undeformed samples cannot be attributed to lattice dislocations or strain fields near grain boundaries. The broadening arises, instead. from long-range correlated displacement fields that extend throughout the grains. The microstrain therefore provides a quantitative measure for distortions far from grain boundaries. This suggests that diffraction-based strategies for inferring the dislocation density in ultrafine-grained metals do not necessarily apply to nanocrystalline materials. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Typ des Eintrags: Artikel
Erschienen: 2009
Autor(en): Stukowski, A. ; Markmann, J. ; Weissmueller, J. ; Albe, K.
Art des Eintrags: Bibliographie
Titel: Atomistic origin of microstrain broadening in diffraction data of nanocrystalline solids
Sprache: Englisch
Publikationsjahr: März 2009
Verlag: Elsevier Science Publishing Company
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Acta Materialia
Jahrgang/Volume einer Zeitschrift: 57
(Heft-)Nummer: 5
DOI: 10.1016/j.actamat.2008.12.01
URL / URN: http://www.sciencedirect.com/science/article/pii/S1359645408...
Kurzbeschreibung (Abstract):

The origin of microstrain broadening in X-ray diffraction patterns of nanocrystalline metals is investigated by comparing data obtained from Virtual diffractograms and from direct analysis of computer-generated samples. A new method is introduced that allows the local deformation gradient to be calculated for each lattice site in the microstructure from atomic coordinates obtained by molecular dynamics simulations. Our results reveal that microstrain broadening in undeformed samples cannot be attributed to lattice dislocations or strain fields near grain boundaries. The broadening arises, instead. from long-range correlated displacement fields that extend throughout the grains. The microstrain therefore provides a quantitative measure for distortions far from grain boundaries. This suggests that diffraction-based strategies for inferring the dislocation density in ultrafine-grained metals do not necessarily apply to nanocrystalline materials. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Freie Schlagworte: X-ray diffraction (XRD), Nanocrystalline materials, Grain boundary structure, Molecular dynamics simulations (MD simulations), Microstrain
Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung
Hinterlegungsdatum: 22 Feb 2012 16:25
Letzte Änderung: 07 Jan 2019 14:10
PPN:
Sponsoren: The authors acknowledge the financial support of the Deutsche Forschungsgemeinschaft (FOR714) and the grants for computing time by the Forschungszentrum Jülich and the HHLR in Darmstadt and Frankfurt.
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