Phase equilibria and mechanical properties of the Ir-W-Al system

T. Omori, K. Makino, K. Shinagawa, I. Ohnuma, R. Kainuma, K. Ishida

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Phase equilibria in the Ir-W, Ir-Al and Ir-W-Al systems at temperatures between 1100 °C and 1600 °C were experimentally investigated using diffusion couples and two- or three-phase alloys, and the mechanical properties of γ′ (L12) strengthened Ir-W-Al alloys were examined by hardness and compression tests at room and elevated temperatures. The phase boundaries between the γ(A1)/ε′(D019), ε′/ε(A3) and ε/ε″(B19) in the Ir-W system at 1400 °C-1600 °C and those between the γ/β(B2) and β/Al2.7Ir in the Ir-Al system at 1100 °C-1400 °C were determined. The phase diagrams in the Ir-rich corner of the Ir-W-Al ternary system at 1300 °C and 1400 °C were also determined. The existence of the γ′ phase of the Ir3(W,Al) ternary compound was confirmed, and this system was found to consist of the γ, γ′, ε, ε′ and β phases in the Ir-rich portion. It was also found from hardness and compression tests up to 1200 °C that Ir-Al-W alloys having the γ + γ′ structure with a small lattice misfit show high hardness and strength at room and high temperatures.

Original languageEnglish
Pages (from-to)154-161
Number of pages8
Publication statusPublished - 2014 Aug 19


  • A. Intermetallics
  • B. Mechanical properties
  • B. Phase stability
  • B. Yield stress
  • D. Microstructure


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