Elevated temperature compressive properties of Zr-modified NiAl
- NASA Lewis Research Center, Cleveland, OH (United States)
Small Zr additions are known to substantially affect the deformation behavior and strength of polycrystalline NiAl, yet little information is currently available regarding the high-temperature properties of such alloys. Utilizing prealloyed powder technology, a series of four NiAl alloys have been produced containing from 0.05 to 0.7 at. pct Zr. The creep behavior of these alloys was characterized in compression between 1,000 and 1,400 K at strain rates ranging from {approximately}0.1 to 10{sup {minus}9} s{sup {minus}1}. All the Zr-modified alloys were significantly stronger than binary NiAl under lower temperature and faster strain-rate conditions; however, the single-phase materials (Zr {le} 0.1 at. pct) and binary NiAl had similar strengths at high temperatures and slow strain rates. The two-phase NiAl-Ni{sub 2}AlZr alloys containing 0.3 and 0.7 at. pct Zr had nearly identical strengths. While the two-phase alloys were stronger than the single-phase materials at all test conditions, the degree of microstructural damage in the two-phase alloys due to internal oxidation during testing appeared to increase with Zr level. Balancing the poor oxidation behavior with the consistent strength advantage of the two-phase alloys, it is concluded that optimum elevated-temperature properties could be obtained in Heusler-strengthened NiAl containing between 0.1 and 0.3 at. pct Zr.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 382514
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 9 Vol. 27; ISSN MMTAEB; ISSN 1073-5623
- Country of Publication:
- United States
- Language:
- English
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