Morphology change of γ′ precipitates in γ/γ′ two-phase microstructure in Co-based superalloys by higher-order alloying

Katsushi Tanaka, Masahiro Ooshima, Norihiko L. Okamoto, Kyosuke Kishida, Haruyuki Inui

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

5 Citations (Scopus)

Abstract

Changes in the morphology of γ′ precipitates in a γ/γ′ two-phase microstructure in Co-based superalloys, which occur through higher-order alloying, have been investigated. The shape of γ′ precipitates changes from a cuboid to an irregularly rounded shape when the Ta content increases to 4 at.%. The irregular shape of the γ′ precipitates changes to cuboid again upon further alloying with 2 at.% Mo. Changes in the morphology of γ′ precipitates are closely related to variations in the lattice misfit between γ and γ′ phases upon alloying. A lattice misfit increases with an increase in Ta content, which makes γ/γ′ interfaces incoherent when the lattice misfit exceeds a critical value. On the contrary, the lattice misfit decreases upon alloying with Mo. Changes in the lattice misfit upon alloying are well explained through the partition behavior of alloying elements and their atomic volume.

Original languageEnglish
Title of host publicationIntermetallic-Based Alloys for Structural and Functional Applications
Pages423-428
Number of pages6
DOIs
Publication statusPublished - 2011
Externally publishedYes
Event2010 MRS Fall Meeting - Boston, MA, United States
Duration: 2010 Nov 292010 Dec 3

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1295
ISSN (Print)0272-9172

Other

Other2010 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA
Period10/11/2910/12/3

ASJC Scopus subject areas

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

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