Partition behavior of alloying elements and phase transformation temperatures in Co-Al-W-base quaternary systems

Toshihiro Omori, Katsunari Oikawa, Jun Sato, Ikuo Ohnuma, Ursula R. Kattner, Ryosuke Kainuma, Kiyohito Ishida

Research output: Contribution to journalArticlepeer-review

164 Citations (Scopus)

Abstract

The phase equilibria among γ (A1), γ′ (L1 2), χ (D0 19), β (B2) and μ (D8 5) phases and the γ′ solvus and γ solidus temperatures were investigated in the Co-Al-W-based quaternary systems with alloying elements of Ti, V, Nb, Ta, Cr, Mo, Mn, Fe, Ni, Si, Zr, Hf, Ru and Ir by electron probe microanalysis (EPMA) using multiphase alloys and by differential scanning calorimetry (DSC). It was found that Ta, Nb, Ti, V, Mo and W are partitioned to the γ′ or χ phase rather than to the γ phase, while Cr, Mn and Fe tend to be distributed to the γ phase. The correlation between the partition coefficient of alloying elements between γ/γ′, γ/χ and γ/β phases and ab initio formation energy of Co 3X (L1 2), Co 3X (D0 19) and CoX (B2) was respectively obtained. It was also found that the γ′ solvus temperature increases by the addition of the γ′ former elements such as Ta, Nb and Ti, which decreases the γ solidus temperature.

Original languageEnglish
Pages (from-to)274-283
Number of pages10
JournalIntermetallics
Volume32
DOIs
Publication statusPublished - 2013 Jan

Keywords

  • A. Intermetallics, miscellaneous
  • B. Alloy design
  • B. Phase diagrams
  • E. Phase stability, prediction
  • E. ab initio calculations

ASJC Scopus subject areas

  • Chemistry(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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