Creep Properties of Directionally Solidified Nb-Modified Ni-Base Superalloy, Mar-M247

Journal Article · Thu Nov 15 04:00:00 EST 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3699-6· OSTI ID:22863173

Costa, A. M. S. ^[1]; Hawk, E.; Dansbury, J. ^[2]; Nunes, C. A. ^[3]

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1. Brazilian Nanotechnology National Laboratory (CNPEM) (Brazil)
2. University of Florida, Materials Science and Engineering Department (United States)
3. Escola de Engenharia de Lorena (USP) (Brazil)

The Ni-base superalloy Mar-M247 is widely used for elevated-temperature applications in both equiaxed and directionally solidified forms. The alloy contains about 3 wt.% Ta. Due to the cost and density of Ta, an atom-for-atom substitution of Nb for Ta was investigated. The creep properties in the temperature range of 750-950 °C and stresses ranging from 200 to 1000 MPa were determined. In general, the creep properties of the Nb-modified Mar-M247 material were very similar to those of Mar-M247 samples at 750 and 850 °C. However, the Mar-M247 samples exhibited superior creep properties at 950 °C. The lower creep properties of the Nb-modified Mar-M247 are likely due to the finer starting microstructure, more rapid coarsening rate of the γ′ and reduced γ′ strengthening effect (i.e., APB energy) of Nb, compared to Ta. No evidence of TCP phases was observed in either alloy.

• OSTI ID: 22863173
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 11 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPARATIVE EVALUATIONS
CREEP
HEAT RESISTING ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
NIOBIUM ADDITIONS
PRESSURE RANGE MEGA PA 100-1000
STRESSES
TEMPERATURE RANGE 1000-4000 K