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Dynamic nanoindentation testing for studying thermally activated processes from single to nanocrystalline metals

Durst, Karsten and Maier, Verena (2015):
Dynamic nanoindentation testing for studying thermally activated processes from single to nanocrystalline metals.
In: Current Opinion in Solid State and Materials Science, Elsevier Science Publishing, pp. 340-353, 19, (6), ISSN 13590286, [Online-Edition: http://dx.doi.org/10.1016/j.cossms.2015.02.001],
[Article]

Abstract

Nanoindentation experiments are widely used for assessing the local mechanical properties of materials. In recent years some new exciting developments have been performed for also analyzing thermally activated processes using indentation based techniques. This paper focuses on how thermally activated dislocation mechanisms can be assessed by indentation strain rate jump as well as creep testing. Therefore, a small overview is given on thermally activated dislocation mechanism and how indentation data from pointed indenters can be interpreted in terms of uniaxial macroscopic testing. This requires the use of the indentation strain rate as introduced by Lucas and Oliver as well as the concepts of Taylor hardening together with Johnson expanding cavity model.

These concepts are then translated to nanoindentation strain rate jump tests as well as nanoindentation long term creep test, where the control of the indenter tip movement as well as the determination of the contact are quite important for reliable data. It is furthermore discussed, that for a steady state hardness test, the interpretation of the hardness data is straightforward and comparable to macroscopic testing. For other conditions where size effects play a major role, hardness data need to be interpreted with consideration for the microstructural length scale with respect to the contact radius.

Finally strain rate jump testing and long term creep testings are used to assess different thermally activated mechanisms in single to nanocrystalline metals such as: Motion of dislocation kink pairs in bcc sx-W, Grain boundary processes in nc-Ni and ufg-Al, and the Portevin-le Chatelier effect in ufg-AA6014.

Item Type: Article
Erschienen: 2015
Creators: Durst, Karsten and Maier, Verena
Title: Dynamic nanoindentation testing for studying thermally activated processes from single to nanocrystalline metals
Language: English
Abstract:

Nanoindentation experiments are widely used for assessing the local mechanical properties of materials. In recent years some new exciting developments have been performed for also analyzing thermally activated processes using indentation based techniques. This paper focuses on how thermally activated dislocation mechanisms can be assessed by indentation strain rate jump as well as creep testing. Therefore, a small overview is given on thermally activated dislocation mechanism and how indentation data from pointed indenters can be interpreted in terms of uniaxial macroscopic testing. This requires the use of the indentation strain rate as introduced by Lucas and Oliver as well as the concepts of Taylor hardening together with Johnson expanding cavity model.

These concepts are then translated to nanoindentation strain rate jump tests as well as nanoindentation long term creep test, where the control of the indenter tip movement as well as the determination of the contact are quite important for reliable data. It is furthermore discussed, that for a steady state hardness test, the interpretation of the hardness data is straightforward and comparable to macroscopic testing. For other conditions where size effects play a major role, hardness data need to be interpreted with consideration for the microstructural length scale with respect to the contact radius.

Finally strain rate jump testing and long term creep testings are used to assess different thermally activated mechanisms in single to nanocrystalline metals such as: Motion of dislocation kink pairs in bcc sx-W, Grain boundary processes in nc-Ni and ufg-Al, and the Portevin-le Chatelier effect in ufg-AA6014.

Journal or Publication Title: Current Opinion in Solid State and Materials Science
Volume: 19
Number: 6
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Nanoindentation, Creep, Strain rate sensitivity
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Physical Metallurgy
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 09 Mar 2015 08:43
Official URL: http://dx.doi.org/10.1016/j.cossms.2015.02.001
Identification Number: doi:10.1016/j.cossms.2015.02.001
Funders: KD wants to thank the DFG for continuous financial support of the last years., Moreover V.M. wants to thank for the financial support by the Zukunftsfond Steiermark project number 6019 “Nanofatigue” at the Montanuniversität Leoben and by the European Research Council (ERC Advanced Grant 2013), under the grant number: 340185 (USMS – Ultra Strong Materials) at the Erich-Schmid-Institute for Materials Science Leoben (Austrian Academy of Science).
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