Sessile locking and strength enhancement in a solid-solution <001> NiAl-0.3Hf single-crystal alloy
- AYT Corp./NASA Lewis Research Center, Cleveland, OH (United States)
- NASA Lewis Research Center, Cleveland, OH (United States)
B2-NiAl is being considered as a candidate material for a wide range of high technology applications. Its low density, high thermal conductivity, high melting temperature, and excellent oxidation resistance make it attractive for high-temperature structural applications such as various components in the combustor and turbine sections of advanced gas turbine engines. However, its room-temperature ductility and high-temperature strength are inadequate, seriously limiting the current potential of this material. These properties need to be improved if NiAl is to compete against current and future generation Ni-ba/se superalloys which, at present, are the materials of choice for most high-temperature structural applications. In order to examine the solid-solution strengthening contribution of Hf, a NiAl alloy containing 0.3 at.% Hf was chosen for mechanical testing at temperatures between 300 and 1,400 K. The yield strength data, thus obtained, indicated that the <001> NiAl-0.3Hf alloy was much stronger than the binary <001> NiAl at high temperatures. However, when compared to a precipitate strengthened NiAl alloy containing 0.5Hf (GE-D218), the NiAl-0.3Hf alloy was found to be weaker at temperatures {le}800 K, but at higher temperatures its strength approached and eventually exceeded that of the D218 alloy. In this paper, the authors report this enhanced strengthening and provide a plausible explanation for such a behavior as evidenced by transmission electron microscopy (TEM) analysis of the as-homogenized and deformed microstructures.
- OSTI ID:
- 651136
- Report Number(s):
- CONF-980202--
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 4-5 Vol. 39; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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