Stability of £¤ precipitates in nickel based oxide dispersion-strengthened superalloys under high-temperature and heavy irradiation conditions

Azusa Konno, Naoko H. Oono, Shigeharu Ukai, Sosuke Kondo, Okinobu Hashitomi, Akihiko Kimura

Research output: Contribution to journalArticlepeer-review

Abstract

The stability of cuboidal £ A precipitates under heavy irradiation was studied for newly developed Ni-based Oxide Dispersion-Strengthened (ODS) superalloys, to explore the suitability of these as core structural materials in Very High-temperature Reactors (VHTR) or Gas-cooled Fast Reactors (GFR). Ion irradiation was applied at a dose level of 100 dpa at 873 K, 1073 K and 1273 K. Under these conditions, £ A precipitates retained their cuboidal shape at 873 K, were deformed somewhat at 1073 K (as predicted by the Nelson-Hudson-Mazey (NHM) model), and were massively deformed and agglomerated at 1273 K. This deformation-agglomeration process is attributed to cascade collision, whereby the increased Gibbs free energy of the disordered phase induces a change in element distribution inside the irradiated area. Ordered, cuboidal £ A precipitates were reproduced from the disordered state after cooling and the cessation of ion irradiation.

Original languageEnglish
Pages (from-to)2260-2266
Number of pages7
JournalMaterials Transactions
Volume60
Issue number11
DOIs
Publication statusPublished - 2019

Keywords

  • Ion-irradiation
  • Nickel-based oxide dispersion strengthened superalloy
  • £B precipitates

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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