Phase stability of the L12 compound and microstructural changes in Co-(W or Mo)-Ta ternary alloys

Hibiki Chinen, Toshihiro Omori, Katsunari Oikawa, Ikuo Ohnuma, Ryosuke Kainuma, Kiyohito Ishida

Research output: Contribution to journalConference articlepeer-review


Microstructural investigations of Co-5W-2.5Ta (at.%) and Co-4Mo-4.5Ta (at.%) ternary alloys were conducted. Fine coherent precipitates were observed in these alloys annealed at 800°C, and the crystal structures of precipitates (γ') and matrix (γ) phase were identified as the L12 and A1 structure, respectively, by transmission electron microscopy. Cellular precipitation with a γ+κ(D019) lamellar structure also proceeded at grain boundaries, and the alloys aged for a longer time only showed the γ+κ two-phase microstructure instead of the γ' phase. With aging at around 800°C, the peak hardness of these alloys with a γ+γ' two phase structure was about 580 Hv.

Original languageEnglish
Pages (from-to)375-379
Number of pages5
JournalMaterials Research Society Symposium Proceedings
Publication statusPublished - 2009 Nov 17
Event2008 MRS Fall Meeting - Boston, MA, United States
Duration: 2008 Dec 22008 Dec 5

ASJC Scopus subject areas

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


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