Phase stability of nickel-base single crystal superalloys containing iridium substituting for ruthenium

Yuhi Mori, Tadaharu Yokokawa, Toshiharu Kobayashi, Hiroshi Harada, Shinsuke Suzuki

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    2 Citations (Scopus)


    Phase stability of Ni-base single crystal superalloys was compared between Ir addition and Ru addition. Investigated alloys were TMS-238 and its derivative alloys. The thermodynamic equilibrium microstructures obtained by a strain aging showed that the volume fractions of γ, γ and topologically close packed (TCP) phases in the alloys were virtually the same to each other without depending on Ir substitution for Ru. On the other hand, the time temperature transformation diagrams obtained by an ordinary aging showed a significant delay in TCP precipitation in the alloys with Ir substitution. The delay in the TCP precipitation might be attributed to the smaller interdiffusion coefficient of Ir-Ni, compared with one of Ru-Ni. The smaller interdiffusion coefficient may affect the kinetics of the TCP precipitation.

    Original languageEnglish
    Pages (from-to)1845-1848
    Number of pages4
    JournalMaterials Transactions
    Issue number10
    Publication statusPublished - 2016



    • Iridium
    • Nickel-Base Single Crystal Superalloy
    • Phase Stability
    • Ruthenium
    • Time Temperature Transformation Diagram
    • Topologically Close Packed Phase

    ASJC Scopus subject areas

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

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