Strength prediction of Ni-base disc superalloys: Modified γ′ hardening models applicable to commercial alloys

L. Wu, T. Osada, I. Watanabe, T. Yokokawa, T. Kobayashi, K. Kawagishi

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The reported strength predictions of γ′ hardening so far for polycrystalline Ni-base superalloys tend to be underestimated. This is mostly due to the difficulty in isolating the γ′ hardening amidst the complicated multi-level strengthening mechanisms of the alloy and negligence of the contribution from γ/γ′ mixture strength. For these reasons, a series of single-crystal tie-line model alloys with specially designed γ′ size and volume fractions was adopted in this work, allowing a direct validation of classical γ′ particle hardening equations for the first time. Using the iso-work assumption, γ′ particle strengthening and γ/γ′ mixture strength at 650 °C were individually extracted from the compression test results. It was found that the classical strengthening models were unable to predict the expected strength increment with increasing γ′ volume fractions. Modified versions of the classical equations were proposed, which gave improved predictability across wider γ’ volume fractions and served as important basis for strength design application.

Original languageEnglish
Article number140103
JournalMaterials Science and Engineering A
Volume799
DOIs
Publication statusPublished - 2021 Jan 2
Externally publishedYes

Keywords

  • Deformation
  • Heat-treatments
  • Ni-base superalloys
  • Precipitation
  • Strength
  • γ/γ′

ASJC Scopus subject areas

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

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