Abstract
Iridium is one of the most promising base metals for future high-temperature structural materials. Attempts to improve the high-temperature strength of Ir have involved solid-solution hardening and coherent hardening. Hf and Zr having a larger atomic size misfit with Ir were found to be the most effective solid-solution hardening and coherent hardening elements on Ir. The idea of multi-component alloying Ir by Hf and Zr was used for the improvement of high-temperature properties of Ir-based alloys in this work. The results show that the monolithic saturated fcc phase has an outstanding Vickers hardness at room temperature, whereas a dual-phase fcc/L12 structure is favorable for high-temperature strength and creep resistance. With a dual-phase fcc/L12 structure composed mostly of fcc phase, the Ir-5Hf-5Zr alloy has a 0.2% yield strength as high as 175 MPa, and a stable creep rate as low as 1.33 × 10-7 S-1 at a stress of 40 MPa even at 1950 °C. Finally, a principle for the design of Ir-based alloy based upon the composition and microstructural morphology was discussed.
Original language | English |
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Pages (from-to) | 1364-1369 |
Number of pages | 6 |
Journal | Intermetallics |
Volume | 14 |
Issue number | 10-11 |
DOIs | |
Publication status | Published - 2006 Oct |
Externally published | Yes |
Keywords
- A. Intermetallics
- B. Microstructure
- C. Mechanical properties at high temperatures
- D. Mechanical properties at ambient temperature
ASJC Scopus subject areas
- Chemistry(all)
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry