On the elastic-viscoplastic behavior of nanocrystalline materials

L. Capolungo, M. Cherkaoui, J. Qu

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

A new constitutive law is introduced to quantify the macroscopic effect of grain boundary dislocation emission on the behavior of pure face center cubic nanocrystalline materials. It is postulated that an emitted dislocation ends its trajectory in the grain boundary opposite to the source causing mass transfer. Dislocation emission by grain boundary ledges, considered here as the primary grain-boundary sources, is modeled as a thermally activated mechanism and the penetration of an emitted dislocation is assimilated as a soft collision. The macroscopic behavior of the material is retrieved via the use of a secant self-consistent scheme. The material is seen as a two-phase composite where the inclusion phase represents grain cores, their behavior is driven by dislocation glide, and where the matrix phase, governed by the newly introduced dislocation emission and penetration mechanism, represents both grain boundaries and triple junctions. The long range stress field arising from the presence of grain boundaries is taken into account in the critical glide resistance stress at 0 K in the inclusion phase. The model is applied to polycrystal copper and results in pure tension and creep are compared to experiments. Good agreements between the experimental measurements and the model predictions are observed.

Original languageEnglish
Pages (from-to)561-591
Number of pages31
JournalInternational Journal of Plasticity
Volume23
Issue number4
DOIs
StatePublished - Apr 2007

Keywords

  • Composite materials
  • Hall-Petch
  • Homogenization
  • Nanocrystalline materials

Fingerprint

Dive into the research topics of 'On the elastic-viscoplastic behavior of nanocrystalline materials'. Together they form a unique fingerprint.

Cite this