Low-angle grain boundary migration in the presence of extrinsic dislocations

A. T. Lim, D. J. Srolovitz, M. Haataja

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

We investigated the migration of a symmetric tilt, low-angle grain boundary (LAGB) under applied shear stress in the presence of extrinsic dislocations. The results demonstrate that there is a threshold stress for the LAGB to depin from extrinsic dislocations. Below the threshold stress, the LAGB remains immobile at zero dislocation climb mobility, while for finite climb mobilities, it migrates at a velocity that is directly proportional to the applied stress, with a proportionality factor that is a function of misorientation, dislocation climb mobility and extrinsic dislocation density. We derive analytical expressions for the LAGB mobility and threshold stress for depinning from extrinsic dislocations. The analytical prediction of the LAGB mobility is in excellent agreement with the simulation as well as experimental results. We discuss the implications of these results for understanding the migration of general grain boundaries.

Original languageEnglish (US)
Pages (from-to)5013-5022
Number of pages10
JournalActa Materialia
Volume57
Issue number17
DOIs
StatePublished - Oct 1 2009

All Science Journal Classification (ASJC) codes

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

Keywords

  • Dislocation boundaries
  • Dislocation dynamics
  • Grain boundary migration
  • Grain boundary mobility

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