Ir-base refractory superalloys for ultra-high temperatures

Y. Yamabe-Mitarai, Y. Ro, T. Maruko, H. Harada

Research output: Contribution to journalArticlepeer-review

100 Citations (Scopus)


The microstructure and compression strengths of Ir-15 at. pet X (X = Ti, Ta, Nb, Hf, Zr, or V) binary alloys at temperatures between room temperature and 1800 °C were investigated to evaluate the potential of these alloys for ultra-high-temperature use. The fee and L12 two-phase structures of these alloys were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The strengths of the Ir-Ta, -Nb, -Hf, and -Zr alloys were above 800 MPa at temperatures up to 1200 °C and about 200 MPa at 1800 °C. The strengths of these alloys under 1000 °C are equivalent to or higher than those of the commercially used Ni-base superalloys, MAR-M247 and CMSX-10. The Nb concentration dependence of strength was investigated using a series of Ir-Nb alloys with Nb concentrations from 0 to 25 at. pet. It was found that the Ir-base alloys were strengthened by L12 precipitation hardening. The potential of the Ir-base alloys for ultra-high temperature use is discussed.

Original languageEnglish
Pages (from-to)537-549
Number of pages13
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Issue number2
Publication statusPublished - 1998
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys


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