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Untangling dislocation and grain boundary mediated plasticity in nanocrystalline nickel

Lohmiller, Jochen and Grewer, Manuel and Braun, Christian and Kobler, Aaron and Kübel, Christian and Schüler, Kerstin and Honkimäki, Veijo and Hahn, Horst and Kraft, Oliver and Birringer, Rainer and Gruber, Patric A. (2014):
Untangling dislocation and grain boundary mediated plasticity in nanocrystalline nickel.
In: Acta Materialia, PERGAMON-ELSEVIER SCIENCE LTD, England, pp. 295-307, 65, ISSN 13596454,
[Online-Edition: http://dx.doi.org/10.1016/j.actamat.2013.10.071],
[Article]

Abstract

Nanocrystalline (nc) materials possess unique mechanical properties, such as very high strength. However, an understanding of the deformation mechanisms and the succession of related microscopic processes that occur during deformation is still incomplete. We used synchrotron-based in situ compression testing to investigate the sequence of deformation mechanisms emerging in bulk nc nickel with a grain size of 30 nm. The study was accompanied by high-resolution grain size analysis and crystal orientation mapping using transmission electron microscopy. Regardless of the initial microstructure, the deformation behavior of electrodeposited nc Ni is initiated by inhomogeneous elastic lattice straining and its accommodation within the grain boundary network, followed by the onset of dislocation plasticity, which was inferred from texture evolution, and stress-driven grain growth. This observation indicates that deformation in nc metals is governed by a succession of different, partly overlapping mechanisms. It is estimated that intragranular dislocation plasticity contributes only about 40% to the overall deformation. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type: Article
Erschienen: 2014
Creators: Lohmiller, Jochen and Grewer, Manuel and Braun, Christian and Kobler, Aaron and Kübel, Christian and Schüler, Kerstin and Honkimäki, Veijo and Hahn, Horst and Kraft, Oliver and Birringer, Rainer and Gruber, Patric A.
Title: Untangling dislocation and grain boundary mediated plasticity in nanocrystalline nickel
Language: English
Abstract:

Nanocrystalline (nc) materials possess unique mechanical properties, such as very high strength. However, an understanding of the deformation mechanisms and the succession of related microscopic processes that occur during deformation is still incomplete. We used synchrotron-based in situ compression testing to investigate the sequence of deformation mechanisms emerging in bulk nc nickel with a grain size of 30 nm. The study was accompanied by high-resolution grain size analysis and crystal orientation mapping using transmission electron microscopy. Regardless of the initial microstructure, the deformation behavior of electrodeposited nc Ni is initiated by inhomogeneous elastic lattice straining and its accommodation within the grain boundary network, followed by the onset of dislocation plasticity, which was inferred from texture evolution, and stress-driven grain growth. This observation indicates that deformation in nc metals is governed by a succession of different, partly overlapping mechanisms. It is estimated that intragranular dislocation plasticity contributes only about 40% to the overall deformation. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Journal or Publication Title: Acta Materialia
Volume: 65
Publisher: PERGAMON-ELSEVIER SCIENCE LTD, England
Uncontrolled Keywords: Nanocrystalline material, Mechanical properties, Texture, Synchrotron diffraction, Plastic deformation
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 10 Feb 2016 10:12
Official URL: http://dx.doi.org/10.1016/j.actamat.2013.10.071
Identification Number: doi:10.1016/j.actamat.2013.10.071
Funders: All authors except V.H. and K.S. received funding from the Deutsche Forschungsgemeinschaft (Grant FOR714), which is gratefully acknowledged., We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities.
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