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Published April 2013 | public
Journal Article

Modeling dislocation nucleation strengths in pristine metallic nanowires under experimental conditions

Abstract

The nature of dislocation sources in small-scale metals is critical to understanding and building models of size-dependent crystalline strength at the nanoscale. Pre-existing dislocations with one pinning point can be readily described as truncated Frank–Read sources, and modeling their operation strengths is straightforward. In contrast, simple and accurate models describing surface dislocation nucleation processes remain elusive. Here, we develop a computationally simple model of heterogeneous dislocation nucleation from free surfaces by combining a continuum description of the nucleation process with the atomistic inputs where accuracy is critical. This model is used to derive the upper strength limits of single-crystalline face-centered cubic nanopillars as a function of size, material and crystal orientation for uniaxial compression and tension. The output parameter space of this model is critically compared against direct atomistic simulations, as well as experiments on tension of pristine gold nanowires and compression of copper nanopillars to highlight its virtues and limitations.

Additional Information

© 2013 Acta Materialia Inc. Published by Elsevier Ltd. Received 6 November 2012; received in revised form 27 December 2012; accepted 28 December 2012. Available online 6 February 2013. The authors gratefully acknowledge the financial support of the Office of the Naval Research (Grant No. N000140910883) and NSF grants DMR-1204864 and CAREER (DMR-0748267). J.R.G. and S.-W.L. are also thankful to the Kavli Nanoscience Foundation for the post-doctoral fellowship support. 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 US Department of Energy Contract No. DE-AC04-94AL85000.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023