Dislocation nucleation on Grain Boundaries: Low angle twist and asymmetric tilt boundaries

Erman Guleryuz, Sinisa Dj Mesarovic

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the mechanisms of incipient plasticity at low angle twist and asymmetric tilt boundaries in fcc metals. To observe plasticity of grain boundaries independently of the bulk plasticity, we simulate nanoindentation of bicrystals. On the low angle twist boundaries, the intrinsic grain boundary (GB) dislocation network deforms under load until a dislocation segment compatible with glide on a lattice slip plane is created. The half loops are then emitted into the bulk of the crystal. Asymmetric twist boundaries considered here did not produce bulk dislocations under load. Instead, the boundary with a low excess volume nucleated a mobile GB dislocation and additional GB defects. The GB sliding proceeded by motion of the mobile GB dislocation. The boundary with a high excess volume sheared elastically, while bulk-nucleated dislocations produced plastic relaxation.

Original languageEnglish (US)
Article number77
JournalCrystals
Volume6
Issue number7
DOIs
StatePublished - Jul 2016

Keywords

  • Intrinsic dislocations
  • Molecular dynamics
  • Nanoindentation
  • Partial dislocations

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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