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Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses

Şopu, Daniel and Albe, Karsten (2015):
Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses.
In: Beilstein Journal of Nanotechnology, pp. 537-545, 6, ISSN 2190-4286,
[Online-Edition: http://dx.doi.org/10.3762/bjnano.6.56],
[Article]

Abstract

The influence of grain size and composition on the mechanical properties of Cu–Zr nanoglasses (NGs) is investigated by molecular dynamics simulations using two model glasses of different alloy composition, namely Cu64Zr36 (Cu-rich) and Cu36Zr64 (Zr-rich). When the grain size is increased, or the fraction of interfaces in these NGs is decreased, we find a transition from a homogeneous to an inhomogeneous plastic deformation, because the softer interfaces are promoting the formation shear transformation zones. In case of the Cu-rich system, shear localization at the interfaces is most pronounced, since both the topological order and free volume content of the interfaces are very different from the bulk phase. After thermal treatment the redistribution of free volume leads to a more homogenous deformation behavior. The deformation behavior of the softer Zr-rich nanoglass, in contrast, is only weakly affected by the presence of glass–glass interfaces, since the interfaces don’t show topological disorder. Our results provide clear evidence that the mechanical properties of metallic NGs can be systematically tuned by controlling the size and the chemical composition of the glassy nanograins.

Item Type: Article
Erschienen: 2015
Creators: Şopu, Daniel and Albe, Karsten
Title: Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses
Language: English
Abstract:

The influence of grain size and composition on the mechanical properties of Cu–Zr nanoglasses (NGs) is investigated by molecular dynamics simulations using two model glasses of different alloy composition, namely Cu64Zr36 (Cu-rich) and Cu36Zr64 (Zr-rich). When the grain size is increased, or the fraction of interfaces in these NGs is decreased, we find a transition from a homogeneous to an inhomogeneous plastic deformation, because the softer interfaces are promoting the formation shear transformation zones. In case of the Cu-rich system, shear localization at the interfaces is most pronounced, since both the topological order and free volume content of the interfaces are very different from the bulk phase. After thermal treatment the redistribution of free volume leads to a more homogenous deformation behavior. The deformation behavior of the softer Zr-rich nanoglass, in contrast, is only weakly affected by the presence of glass–glass interfaces, since the interfaces don’t show topological disorder. Our results provide clear evidence that the mechanical properties of metallic NGs can be systematically tuned by controlling the size and the chemical composition of the glassy nanograins.

Journal or Publication Title: Beilstein Journal of Nanotechnology
Volume: 6
Uncontrolled Keywords: enhanced plasticity, metallic glasses, nanoglasses, shear bands
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: 02 Mar 2015 09:36
Official URL: http://dx.doi.org/10.3762/bjnano.6.56
Additional Information:

This article is part of the Thematic Series "Advances in nanomaterials II". Guest Editor: H. Hahn

Identification Number: doi:10.3762/bjnano.6.56
Funders: The authors acknowledge the financial support of the Deutsche Forschungsgemeinschaft (DFG) through project Al-578-15. , A DAAD-PPP travel grant with University of Helsinki is also acknowledged.
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