Deformation and Phase Transformations During Cyclic Oxidation of Ni-Al and Ni-Pt-Al
- ORNL
- Tennessee Technological University
The reversible high-temperature {gamma}' to {beta} phase transformation may be critical to explaining the unusual high-temperature oxidation behavior of (Ni,Pt)Al alloys and coatings. During high-temperature, high-frequency (1 h) cyclic oxidation in dry, flowing O{sub 2}, unprecedented macroscopic deformation was observed in two-phase ({gamma}'+{beta}) cast specimens of Hf-doped Ni-Al at 1,150 C and Hf-doped Ni-Pt-Al at 1,100 and 1,150 C, Outside of this two-phase field or when the cycle frequency was decreased to 100h, no deformation was observed. Using high-temperature x-ray diffraction in an inert environment, the {beta}-to-{gamma}' phase ratio was observed to increase above 1,000 C, causing a 2.5% volume change. The addition of platinum appeared to lower the transformation temperature consistent with the deformation observed in castalloys and rumpling of simple and platinum-modified aluminide coatings.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); High Temperature Materials Laboratory
- Sponsoring Organization:
- FE USDOE - Office of Fossil Energy (FE)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1003147
- Journal Information:
- Journal of the Minerals Metals & Materials Society (JOM), Journal Name: Journal of the Minerals Metals & Materials Society (JOM) Journal Issue: 1 Vol. 58; ISSN JOMMER; ISSN 1047-4838
- Country of Publication:
- United States
- Language:
- English
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