Crystallography and elastic anisotropy in fatigue crack nucleation at nickel alloy twin boundaries

Xiaoxian Zhang, Jean Charles Stinville, Tresa M. Pollock, Fionn P.E. Dunne

Research output: Contribution to journalArticlepeer-review


Fatigue crack nucleation at annealing twin boundaries (TBs) within polycrystal nickel-based superalloy René 88DT is investigated with a microstructure-sensitive crystal plasticity (CP) model, digital image correlation strain measurements and experimental SEM crack nucleation observations. Strong slip localizations at TBs were experimentally observed and predicted by the CP model, which also showed high predicted geometrically necessary dislocation and corresponding stored energy densities, capturing experimental observations of crack nucleation. In a systematic study, elastic anisotropy was found to drive local elastic constraint and hence resolved shear stress, slip activation, GND density and stored energy density, demonstrating for this reason that TBs are preferential sites for crack nucleation in this alloy. The parent grain / twin pair crystallographic orientation with respect to remote loading was also demonstrated to be key to slip activation parallel to TBs and hence to stored energy density and fatigue crack nucleation, and the range of most damaging parent grain orientations has been identified.

Original languageEnglish (US)
Article number104538
JournalJournal of the Mechanics and Physics of Solids
StatePublished - Oct 2021
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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