Fatigue fracture at bicrystal interfaces: Experiment and theory

P. Peralta, C. Laird

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Copper bicrystals with isoaxial [149] twist boundaries and a (149)/(001) "random" boundary were notched at the interface, left or right regarding the slip geometry, and intergranular cracks were propagated under strain control, to study how dislocation structure, crystallography and strain localization affect crack growth. Forward slip at the crack surface was favored regardless of growth direction or misorientation, whereas pre-existent multiple slip around the boundary reduced the dependence of crack kinetics on the growth direction. A model is proposed for intergranular crack growth based on crack tip deformation via crystallographic slip bands and simplifying assumptions about the effects of mode I stress fields on the strain. The experimental and theoretical results, along with published data, provide evidence that an optimal slip geometry exists for fatigue crack propagation. This idea is used to explain experimental results on directional dependence of intergranular cracking of bicrystals, suggesting that the kinematics of deformation has to be considered besides the energetics of dislocation nucleation at a crack tip to explain such results.

Original languageEnglish (US)
Pages (from-to)2001-2020
Number of pages20
JournalActa Materialia
Volume46
Issue number6
DOIs
StatePublished - Mar 23 1998
Externally publishedYes

ASJC Scopus subject areas

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

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