Microstructural degradation of polycrystalline superalloys from oxidized carbides and implications on crack initiation

Research output: Contribution to journalArticlepeer-review

Authors

  • Paraskevas Kontis
  • Angus J. Wilkinson
  • Roger C. Reed
  • Dierk Raabe
  • Baptiste Gault

Colleges, School and Institutes

External organisations

  • Max-Planck-Institut für Eisenforschung
  • Department of Materials, University of Oxford

Abstract

Surface connected carbides in a polycrystalline superalloy oxidized at 750 °C in air were studied as potential crack initiation sites. Lattice rotations measured in the γ/γ′ grains using high-resolution electron backscatter diffraction enabled investigation of the plastic deformation induced solely by the oxidation of carbides. Dislocations were found to enhance γ′ precipitate dissolution kinetics, resulting in soft recrystallized regions in the vicinity of the oxidized carbide with substantial compositional variation compared to the original γ/γ′ microstructure. Ramifications of such deleterious oxidized carbides alongside soft recrystallized regions on the crack initiation life in superalloys are discussed.

Details

Original languageEnglish
Pages (from-to)59-63
Number of pages5
JournalScripta Materialia
Volume147
Early online date8 Jan 2018
Publication statusPublished - 1 Apr 2018

Keywords

  • Atom probe tomography, Oxidized carbides, Partial dislocation, Recrystallization, γ′ Dissolution