Abstract
Two quaternary systems, Ir-Nb-Ni-Al and Ir-Nb-Pt-Al, were successively investigated to assess their possible use in ultra-high-temperature applications. The phase relationships concentrated on the fcc/L12 two-phase region were primarily established, and the mechanical properties were studied, Ir-Nb-Ni-Al quaternary alloys around the Ir-rich or Ni-rich corners of the Ir-Nb-Ni-Al tetrahedron showed a coherent fcc/L12 two-phase structure, analogous to that of Ni-base superalloys; however, most of the alloys presented three or four phases with two types of L12 phases. Although these alloys showed a high compressive strength at high temperature, they exhibited a higher creep rate than Ir-base binary and ternary alloys. Another quaternary system, Ir-Nb-Pt-Al, showed promising results. Only an fcc/L12 two-phase structure was found in all the alloys investigated with compositions ranging from the Ir-rich side to the Pt-rich side, and the lattice misfit between the fcc and L12 phases was small. The high-temperature strength at 1200 °C of Ir-Nb-Pt-Al alloys was higher than that of Ir-Nb-Ni-Al alloys with the same Ir content (at. pct). Moreover, Ir-Nb-Pt-Al alloys exhibited excellent creep resistance at 1400 °C and 100 MPa.
| Original language | English |
|---|---|
| Pages (from-to) | 539-545 |
| Number of pages | 7 |
| Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
| Volume | 36 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2005 Mar |
| Externally published | Yes |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys