Interpreting the stress-strain response of Al micropillars through gradient plasticity

Xu Zhang, Katerina E. Aifantis, Alfonso H.W. Ngan

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Micropillar compression has fascinated the materials and mechanics communities for over a decade, due to the unique stochastic effects and slip zones that dictate their stress-strain curves and microstructure. Although plethora studies exist that capture experimentally the mechanical response of various types of micropillars, limited theoretical models can interpret the observed behavior. Particularly, single crystal micropillars exhibit multiple serrations in their stress-strain response, indicating the activation of slip zones, while bi-crystal pillars, in which the grain boundary lies parallel to the pillar axis, do not display such serrations, but rather a distinct "knee", which indicates dislocation pileups at the grain boundary. In-situ synchrotron microdiffraction experiments have illustrated that not only dislocations, but also significant plastic strain gradients develop during micropillar compression. In the present study, therefore, appropriate gradient plasticity models that can account for the pillar microstructure, are successfully used to capture the stress-strain response of single- and bi-crystal Al pillars.

Original languageEnglish (US)
Pages (from-to)38-45
Number of pages8
JournalMaterials Science and Engineering A
Volume591
DOIs
StatePublished - Jan 3 2014

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Keywords

  • Gradient plasticity
  • Grain-boundary yielding
  • Micropillars
  • Strain bursts

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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