Stress-dependent dislocation core structures leading to non-Schmid behavior

Di Qiu, Pengyang Zhao, Dallas R. Trinkle, Yunzhi Wang

Research output: Contribution to journalArticlepeer-review

Abstract

The stress-dependent core structures of dislocations for basal slip in magnesium are calculated using ab initio generalized stacking fault energy surface and microscopic phase-field method. The dissociation of dislocation cores exhibits the dependence on the non-shear component in the stress tensor; the Peierls stress is found to either become virtually zero or increase by an order of magnitude, depending on the applied shear stress magnitude and direction. The results, in contrast to the classical Schmid's law for crystal plasticity, are explained using the Escaig stress concept and the resulting implication on plastic deformation is discussed. IMPACT STATEMENT Dependence of dislocation core structure on stress is predicted using a microscopic phase-field model with subatomic resolution, revealing non-Schmid behavior together with significant influence on the Peierls stress.

Original languageEnglish (US)
Pages (from-to)134-140
Number of pages7
JournalMaterials Research Letters
Volume9
Issue number3
DOIs
StatePublished - 2021

Keywords

  • Escaig stress
  • Magnesium
  • Peierls stress
  • basal dislocation
  • phase-field

ASJC Scopus subject areas

  • Materials Science(all)

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