Creep of Ni-Al and Ni-Cr-Al Superalloy Foams
نویسندگان
چکیده
The steady-state creep rate of Ni-base metallic foams, with superalloy composition (in wt. pct) Ni7.8∼9.1Al (relative density, ρ = 2.5-2.6) and Ni-13.5∼16.6Cr-5.1∼8.9Al (ρ = 2.8∼3.0), was measured under a range of temperatures (680∼825°C) and applied stresses (0.1∼0.3 MPa), and compared with that of NiAl intermetallic foams (ρ = 5.3). The stress exponent and activation energy are within the expected range for bulk superalloys. At 825°C, Ni-Cr-Al foams display creep rates lower by ca. a factor 10 as compared to Ni-Al foams, and higher by ca. a factor 10 as compared to the NiAl intermetallic foams. These differences are discussed in terms of foam density and strut material creep resistance.
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