Coble creep in a powder-metallurgical nickel aluminide of composition Ni–22.8Al–0.6Hf–0.1B (at. %)
- 1 June 1988
- journal article
- Published by Springer Nature in Journal of Materials Research
- Vol. 3 (3) , 403-406
- https://doi.org/10.1557/jmr.1988.0403
Abstract
Coble creep, which is controlled by mass transport along grain boundaries, has been identified in a powder-metallurgically prepared nickel aluminide with the nominal composition Ni–22.8Al–0.6Hf–0.1B (at. %). Diffusional creep rates∊as a function of temperatureT, stressσ, and grain sizeLare well described by∊ = 33δbDbΩσ(kTL3), whereδbDb= 3 × 10−6m3s−1× exp [– (313 kJ/mol)/(RT) (δbis the diffusional grain boundary width,Dbis the grain boundary diffusivity,Ris the gas constant, andTis the absolute temperature). The activation energy of 313 kJ/mol is unusually high as compared to that for volume diffusion.Keywords
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