Weinberger, Christopher R. and Jennings, Andrew T. and Kang, Keonwook and Greer, Julia R. (2012) Atomistic simulations and continuum modeling of dislocation nucleation and strength in gold nanowires. Journal of the Mechanics and Physics of Solids, 60 (1). pp. 84-103. ISSN 0022-5096 http://resolver.caltech.edu/CaltechAUTHORS:20120104-143903753
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The strength of true metallic nanowires and nanopillars (diameters below 100 nm) is known to be higher than the strength of bulk metals and is most likely controlled by dislocation nucleation from free surfaces. Dislocation nucleation is a thermally activated process that is sensitive to both temperature and strain rate. However, most simulations rely on high strain rate molecular dynamics to investigate strength and nucleation, which is limited by short molecular dynamics time scales. In this work, the energetics of dislocation nucleation in gold nanowires are computed using atomistic simulations, and transition state theory is used to estimate the strength at experimental strain rates revealing detailed information outside the realm accessible to molecular dynamics simulations. This allows investigation into the competition between thermally activated dislocation nucleation and other failure mechanisms such as elastic and structural instabilities. Additionally, the mechanisms of dislocation nucleation are compared against analytical continuum models which allow a better understanding of the nucleation process including the effects of the wire surfaces. This study helps clarify and consolidate our understanding of the nature of dislocation nucleation in small structures.
|Additional Information:||© 2011 Elsevier Ltd. Received 9 June 2011; revised 18 September 2011; Accepted 22 September 2011. Available online 1 October 2011. The authors wish to acknowledge useful discussions with Dr. Jonathan Zimmerman and Prof. Wei Cai. This research was supported in part by an appointment to the Sandia National Laboratories Truman Fellowship in National Security Science and Engineering, sponsored by Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) as Operator of Sandia National Laboratories under its U.S. Department of Energy Contract no. DE-AC04-94AL85000. A.T.J. and J.R.G. gratefully acknowledge the financial support of the National Science Foundation through ATJ's NSF Graduate Research Fellowship and JRG's CAREER grant (DMR-0748267). K.K. acknowledges support from Los Alamos National Laboratories through LDRD-DR.|
|Subject Keywords:||Microstructures; Dislocations; Nucleation|
|Official Citation:||Christopher R. Weinberger, Andrew T. Jennings, Keonwook Kang, Julia R. Greer, Atomistic simulations and continuum modeling of dislocation nucleation and strength in gold nanowires, Journal of the Mechanics and Physics of Solids, Volume 60, Issue 1, January 2012, Pages 84-103, ISSN 0022-5096, 10.1016/j.jmps.2011.09.010. (http://www.sciencedirect.com/science/article/pii/S0022509611001840)|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||04 Jan 2012 23:01|
|Last Modified:||04 Jan 2012 23:01|
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