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Competing deformation mechanisms in nanocrystalline metals and alloys: Coupled motion versus grain boundary sliding

Schäfer, Jonathan and Albe, Karsten (2012):
Competing deformation mechanisms in nanocrystalline metals and alloys: Coupled motion versus grain boundary sliding.
In: Acta Materialia, Elsevier Science Publishing Company, pp. 6076-6085, 60, (17), [Online-Edition: http://dx.doi.org/10.1016/j.actamat.2012.07.044],
[Article]

Abstract

Plastic deformation of nanocrystalline Pd and Cu as well as the demixing systems Cu–Nb and Cu–Fe is studied by means of atomic-scale computer simulations. The microstructures are specifically chosen to facilitate mesoscopic grain boundary sliding. The influence of segregating solutes on the deformation mechanisms is studied and different cases of solute distributions are compared. We find that the competition between mesoscopic grain boundary sliding and coupled grain boundary motion is controlled by the concentration and distribution of segregating solutes. By analyzing the microstructural evolution and dislocation activity we make a connection between the atomistic solute distribution and the mechanisms of deformation, explaining the observed stress–strain behavior. The detailed analysis of the normal grain boundary motion reveals a stick–slip behavior and a coupling factor which is consistent with results from bicrystal simulations.

Item Type: Article
Erschienen: 2012
Creators: Schäfer, Jonathan and Albe, Karsten
Title: Competing deformation mechanisms in nanocrystalline metals and alloys: Coupled motion versus grain boundary sliding
Language: English
Abstract:

Plastic deformation of nanocrystalline Pd and Cu as well as the demixing systems Cu–Nb and Cu–Fe is studied by means of atomic-scale computer simulations. The microstructures are specifically chosen to facilitate mesoscopic grain boundary sliding. The influence of segregating solutes on the deformation mechanisms is studied and different cases of solute distributions are compared. We find that the competition between mesoscopic grain boundary sliding and coupled grain boundary motion is controlled by the concentration and distribution of segregating solutes. By analyzing the microstructural evolution and dislocation activity we make a connection between the atomistic solute distribution and the mechanisms of deformation, explaining the observed stress–strain behavior. The detailed analysis of the normal grain boundary motion reveals a stick–slip behavior and a coupling factor which is consistent with results from bicrystal simulations.

Journal or Publication Title: Acta Materialia
Volume: 60
Number: 17
Publisher: Elsevier Science Publishing Company
Uncontrolled Keywords: Nanocrystalline materials, Grain boundary segregation, Plastic deformation, Molecular dynamics
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 31 Aug 2012 09:55
Official URL: http://dx.doi.org/10.1016/j.actamat.2012.07.044
Identification Number: 0.1016/j.actamat.2012.07.044
Related URLs:
Funders: The authors acknowledge the financial support of the Deutsche Forschungsgemeinschaft (FOR714) and the grants of computer time from Forschungszentrum Jülich.
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