Mechanical properties of Ir-15Hf-xZr ternaries with two-phase fcc/L1 2 or L12/L12 structure at room and high temperatures

J. B. Sha, Y. Yamabe-Mitarai, H. Harada

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Iridium is expected as the most promising base metal for future ultra-high temperature structural materials. With large atomic size misfit to Ir, Hf and Zr were found to be the most effective solid-solution and precipitate hardening elements. Multi-component alloying of Ir by Hf and Zr is employed in this work to promote the high-temperature mechanical properties of Ir-based alloys. The Ir-15Hf binary alloy was used as a base material and Ir was further replaced by 1, 5, 10, and 15 mol % Zr. The results showed that with an increasing Zr content the microstructure of the Ir-15Hf-(1-15) Zr alloys changed from two-phase fcc/L12 to L12/L12 structure. From room to high temperatures, considerable hardening took place when the microstructure contained significant amount of saturated fee phase, while the L12 dominating or two-phase L12/L12 microstructure showed lower hardening efficiency. Even at 1800°C, the Ir-15Hf-1Zr alloy containing significant amount of saturated fcc-phase had the yield 0.2% strength of as high as 340MPa. The intergranular fracture could govern the failure of the Ir-Hf-Zr ternary alloys. Finally, a principle for the design of the Ir-based alloy with high strength at elevated temperatures based upon the composition and fracture mode was discussed and proposed.

Original languageEnglish
Title of host publicationMaterials Science and Technology 2005 - Proceedings of the Conference
Number of pages10
Publication statusPublished - 2005 Dec 1
Externally publishedYes
EventMaterials Science and Technology 2005 Conference - Pittsburgh, PA, United States
Duration: 2005 Sep 252005 Sep 28

Publication series

NameMaterials Science and Technology
ISSN (Print)1546-2498


OtherMaterials Science and Technology 2005 Conference
Country/TerritoryUnited States
CityPittsburgh, PA


  • High- temperature behaviors
  • Ir-Hf-Zr ternary alloys
  • L1 phase
  • Solid-solution fee phase

ASJC Scopus subject areas

  • Engineering(all)


Dive into the research topics of 'Mechanical properties of Ir-15Hf-xZr ternaries with two-phase fcc/L1 2 or L12/L12 structure at room and high temperatures'. Together they form a unique fingerprint.

Cite this