Dislocation density distribution at slip band-grain boundary intersections

Research output: Contribution to journalArticle

Authors

  • Yi Guo
  • Edmund Tarleton
  • Felix Hofmann
  • Angus Wilkinson
  • Ben Britton

Colleges, School and Institutes

External organisations

  • Imperial College London
  • University of Oxford

Abstract

We study the mechanisms of slip transfer at a grain boundary, in titanium, using Differential Aperture X-ray Laue Micro-diffraction (DAXM). This 3D characterisation tool enables measurement of the full (9-component) Nye lattice curvature tensor and calculation of the density of geometrically necessary dislocations (GNDs). We observe dislocation pile-ups at a grain boundary, as the neighbour grain prohibits easy passage for dislocation transmission. This incompatibility results in local micro-plasticity within the slipping grain, near to where the slip planes intersect the grain boundary, and we observe bands of GNDs lying near the grain boundary. We observe that the distribution of GNDs can be significantly influenced by the formation of grain boundary ledges that serve as secondary dislocation sources. This observation highlights the non-continuum nature of polycrystal deformation and helps us understand the higher order complexity of grain boundary characteristics.

Details

Original languageEnglish
Pages (from-to)172-183
Number of pages12
JournalActa Materialia
Volume182
Early online date23 Oct 2019
Publication statusPublished - Jan 2020

Keywords

  • Disconnections, Geometrically necessary dislocations, Grain boundary ledge, High-energy X-ray diffraction, Slip transmission