Heteroepitaxial recrystallization: A new mechanism discovered in a polycrystalline γ-γ′ nickel based superalloy

Marie Agathe Charpagne, Thomas Billot, Jean Michel Franchet, Nathalie Bozzolo

Research output: Contribution to journalArticlepeer-review

Abstract

The dynamic recrystallization mechanisms and kinetics of a recently developed γ-γ′ nickel based superalloy are studied at different subsolvus temperatures. Special care is paid to the evolution of γ′ particles and their influence on recrystallization phenomena. An original dynamic recrystallization mechanism is highlighted thanks to the combined use of Energy Dispersive Spectrometry and Electron BackScattered Diffraction mapping techniques. This mechanism leads to the formation of large heteroepitaxial pairs, made of a primary precipitate embedded in a recrystallized grain having the same crystallographic orientation. Recrystallization nuclei arise from inverse precipitation of γ phase at the rim of primary γ′ precipitates, prior to deformation. This heteroepitaxial recrystallization mechanism is reported here for the first time. It controls dynamic microstructure evolution at low strains and is then progressively replaced by the conventional discontinuous necklace recrystallization process at higher strains.

Original languageEnglish (US)
Pages (from-to)685-694
Number of pages10
JournalJournal of Alloys and Compounds
Volume688
DOIs
StatePublished - 2016
Externally publishedYes

Keywords

  • Dynamic recrystallization
  • Heteroepitaxy
  • Inverse precipitation
  • Microstructure
  • γ-γ′ nickel based superalloys
  • γ′ precipitates

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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