Shearing of γ́ precipitates by a (112) dislocation ribbons in Ni-base superalloys: a phase field approach

V. A. Vorontsov, C. Shen, Y. Wang, D. Dye, C.M.F. Rae

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46 Citations (Scopus)

Abstract

The phase field model of dislocations has been used to study the propagation of dislocation ribbons with an overall Burgers vector of a(112) through a simulated Ni-base superalloy. The driving force for dislocation dissociation reactions and formation of planar faults isincorporated into the free energy functional using periodic functions specially fitted to ab initio γ-surface data. The model shows that the mechanism of cutting of the γ precipitates by these ribbons exhibits significant dependence on stress magnitude, orientation and precipitate shape. In the case of mixed screw-edge ribbons a change of shearing mode is observed, from stacking fault shear to anti-phase boundary shear, when the applied stress approaches the yield of the material. This transition is absent in pure edge ribbons.

Original languageEnglish
Pages (from-to)4110-4119
Number of pages10
JournalActa Materialia
Volume58
Issue number12
DOIs
Publication statusPublished - 1 Jan 2010

Keywords

  • dislocation dissociation
  • phase field
  • primary creep
  • shockley partials
  • stacking faults
  • Ni-base superalloys

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