Surface versus bulk nucleation of dislocations during contact

L. Nicola, A. F. Bower, K.-S. Kim, A. Needleman*, E. Van der Giessen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

45 Citations (Scopus)
270 Downloads (Pure)

Abstract

The indentation of single crystals by a periodic array of flat rigid contacts is analyzed using discrete dislocation plasticity. Plane strain analyses are carried out with the dislocations all of edge character and modeled as line singularities in a linear elastic solid. The limiting cases of frictionless and perfectly sticking contacts are considered. The effects of contact size, dislocation source density, and dislocation obstacle density and strength on the evolution of the mean indentation pressure are explored, but the main focus is on contrasting the response ofcrystals having dislocation sources on the surface with that of crystals having dislocation sources in the bulk. When there are only bulk sources, the mean contact pressure for sufficiently large contacts is independent of the friction condition, whereas for suificiently small contact sizes, there isa significant dependence on the friction condition. When there are only surface dislocation sources the mean contact pressure increases much more rapidly with indentation depth than when bulk sources are present and the mean contact pressure is very sensitive to the strength of the obstacles to dislocation glide. Also, on unloading a layer of tensile residual stress develops when surface dislocation sources dominate. (c) 2007 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)1120-1144
Number of pages25
JournalJournal of the Mechanics and Physics of Solids
Volume55
Issue number6
DOIs
Publication statusPublished - Jun-2007

Keywords

  • contact mechanics
  • discrete dislocation plasticity
  • indentation
  • residual stress
  • size effect
  • DISCRETE DISLOCATION
  • THIN-FILMS
  • PLASTICITY ANALYSIS
  • SINGLE-CRYSTALS
  • NANOINDENTATION
  • INDENTATION
  • DEFORMATION
  • COMPRESSION
  • SIMULATION
  • THRESHOLD

Cite this