The role of interfaces in enhancing the yield strength of composites and polycrystals

K. E. Aifantis, J. R. Willis

Research output: Contribution to journalArticlepeer-review

166 Scopus citations

Abstract

A deformation-theory version of strain-gradient plasticity is employed to assess the influence of microstructural scale on the yield strength of composites and polycrystals. The framework is that recently employed by Fleck and Willis (J. Mech. Phys. Solids 52 (2004) 1855-1888), but it is enhanced by the introduction of an interfacial "energy" that penalises the build-up of plastic strain at interfaces. The most notable features of the new interfacial potential are: (a) internal surfaces are treated as surfaces of discontinuity and (b) the scale-dependent enhancement of the overall yield strength is no longer limited by the "Taylor" or "Voigt" upper bound. The variational structure associated with the theory is developed in generality and its implications are demonstrated through consideration of simple one-dimensional examples. Results are presented for a single-phase medium containing interfaces distributed either periodically or randomly.

Original languageEnglish (US)
Pages (from-to)1047-1070
Number of pages24
JournalJournal of the Mechanics and Physics of Solids
Volume53
Issue number5
DOIs
StatePublished - May 2005

Keywords

  • Hall-Petch effect
  • Strain-gradient plasticity
  • Variational principles

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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