Alloying Effects on the Competition Between Discontinuous Precipitation Versus Continuous Precipitation of δ/η Phases in Model Ni-Based Superalloys

Satoru Kobayashi, Tomoki Otsuka, Rikuryo Watanabe, Kyosuke Sagitani, Masaki Okamoto, Kako Tokutomi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Alloying effects on the competition between discontinuous and continuous precipitation of δ-Ni3Nb (D0a) phase and η-Ni3Ti (D024) phase were investigated in model Ni-Cr-Fe-Nb and Ni-Ti-based alloys, respectively, to aim at designing polycrystalline Ni based superalloys with better temperature capability. Discontinuous precipitation tends to occur at lower temperatures, while continuous precipitation dominates at higher temperatures in the two alloy systems. The addition of Mo promotes continuous precipitation with respect to discontinuous precipitation while that of Ti promotes discontinuous precipitation rather than continuous precipitation in δ phase precipitation alloys. A replacement of Ti with Mo promotes continuous precipitation with respect to discontinuous precipitation in η phase precipitation alloys at 800 °C. The observed alloying effects are discussed in terms of chemical driving force, interfacial energy between the matrix phase and the δ(η) phases, and coherency strain caused by the formation of the metastable phases prior to the formation of δ/η phases.

Original languageEnglish
Title of host publicationSuperalloys 2020 - Proceedings of the 14th International Symposium on Superalloys
EditorsSammy Tin, Mark Hardy, Justin Clews, Jonathan Cormier, Qiang Feng, John Marcin, Chris O'Brien, Akane Suzuki
PublisherSpringer Science and Business Media Deutschland GmbH
Pages163-170
Number of pages8
ISBN (Print)9783030518332
DOIs
Publication statusPublished - 2020
Externally publishedYes
Event14th International Symposium on Superalloys, Superalloys 2021 - Seven Springs, United States
Duration: 2021 Sep 122021 Sep 16

Publication series

NameMinerals, Metals and Materials Series
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Conference

Conference14th International Symposium on Superalloys, Superalloys 2021
CountryUnited States
CitySeven Springs
Period21/9/1221/9/16

Keywords

  • Discontinuous precipitation
  • Microstructural design
  • Polycrystalline superalloys

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy Engineering and Power Technology
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Alloying Effects on the Competition Between Discontinuous Precipitation Versus Continuous Precipitation of δ/η Phases in Model Ni-Based Superalloys'. Together they form a unique fingerprint.

Cite this