Surface stress effects on the yield strength in nanotwinned polycrystal face-centered-cubic metallic nanowires

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Original languageEnglish
Article number101002
Journal / PublicationJournal of Applied Mechanics, Transactions ASME
Issue number10
Publication statusPublished - Oct 2014


The influence of surface stress on the yield strength of nanotwinned polycrystal face-centered-cubic (FCC) metallic nanowire is theoretically investigated. The contribution of surface boundaries on the strengthening/ softening is analyzed in the framework of continuum mechanics theory by accounting for the surface energy effects. The other strengthening mechanisms originated from the inner boundaries are described by the Taylor model for the nanotwinned polycrystalline metals. The theoretical results demonstrate that the yield strength of nanotwinned polycrystal wires is dependent on the twin spacing, grain size and the geometrical size of the wire. The surface stress effects on the strength perform more and more significantly with decreasing the wire diameter, especially for the diameter smaller than 20 nm. In addition, the dependence of surface stress on the strength is also relevant to the size of microstructures as well as the magnitude and direction of surface stress. These results may be useful in evaluating the size-dependent mechanical performance of nanostructured materials. © 2014 by ASME.

Research Area(s)

  • grain size yield strength, nanotwinned polycrystal nanowire, surface stress, Taylor mode, twin spacing