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Experimental Evidence that the Onset of Mechanical Softening in Nanocrystalline Metals is Strain Rate Dependent

Published online by Cambridge University Press:  01 February 2011

Liwei Wang
Affiliation:
[email protected], Auburn University, Materials Engineering, 275 Wilmore Lab, Auburn, AL, 36849-5341, United States, 334-844-4733
Bart Prorok
Affiliation:
[email protected], Auburn University, Materials Engineering, 275 Wilmore Lab, Auburn, AL, 36849-5341, United States, 334-844-4733
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Abstract

This paper reports on the influence of strain rate on the onset of mechanical softening of nanocrystalline gold at room temperature. Micro-tensile testing was performed with applied strain rates on the order of 10−4 s−1 to 10−6 s−1. Our results defined a threshold strain rate, whereby plastic deformation at larger rates was dominated by dislocation processes and at smaller rates by one or more other deformation mechanisms. Furthermore, the data suggested that the critical grain size for inverse Hall-Petch behavior was strain rate sensitive.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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