Average yielding and weakest link statistics in micron-scale plasticity

Péter Dusán Ispánovity, Ádám Hegyi, István Groma, Géza Györgyi, Kitti Ratter, Daniel Weygand

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Micron-scale single-crystalline materials deform plastically via large intermittent strain bursts that make the deformation process non-deterministic. Here we investigate this stochastic phenomenon by analyzing the plastic response of an ensemble of specimens differing only in the initial arrangement of dislocations. We apply discrete dislocation dynamics simulations and microcompression tests on identically fabricated Cu single-crystalline micropillars. We find that a characteristic yield stress can be defined in the average sense for a given specimen ensemble, where the average and the variance of the plastic strain start to increase considerably. In addition, in all studied cases the stress values at a given strain follow a Weibull distribution with similar Weibull exponents, which suggests that dislocation-mediated plastic yielding is characterized by an underlying weakest-link phenomenon. These results are found not to depend on fine details of the actual set-up; rather, they represent general features of micron-scale plasticity.

Original languageEnglish
Pages (from-to)6234-6245
Number of pages12
JournalActa Materialia
Volume61
Issue number16
DOIs
Publication statusPublished - Sep 1 2013

Keywords

  • Dislocation dynamics
  • Flow stress
  • Microcompression
  • Plastic deformation
  • Single crystal

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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