Thermal activation of fatigue crack growth: analysing the mechanisms of fatigue crack propagation in superalloys
Thermal activation of fatigue crack growth: analysing the mechanisms of fatigue crack propagation in superalloys
A method for deriving apparent activation energies, Eapp, for fatigue crack growth (FCG) is presented. It is shown how these Eapp values can be used to analyse the main underlying mechanism causing the progression of the crack. The Eapp values for fatigue crack growth in air and vacuum, and with and without a dwell are obtained for a range of Ni based superalloys for turbine disc applications. The apparent activation energies range from about zero to about 300kJ/mol. The analysis allows identification of alloys that are prone to FCG through diffusion controlled mechanisms, notably grain boundary oxidation or grain boundary creep, as well as alloys that are nearly immune to FCG by grain boundary oxidation or creep.
activation energy, N18, U720Li, RR1000, nickel superalloy, fatigue crack propagation, turbine disc alloys, creep, oxidation, fractography, thermal activation, diffusion, creep-fatigue
279-289
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Reed, P.A.S.
8b79d87f-3288-4167-bcfc-c1de4b93ce17
September 2008
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Reed, P.A.S.
8b79d87f-3288-4167-bcfc-c1de4b93ce17
Starink, M.J. and Reed, P.A.S.
(2008)
Thermal activation of fatigue crack growth: analysing the mechanisms of fatigue crack propagation in superalloys.
Materials Science and Engineering: A, 491 (1-2), .
(doi:10.1016/j.msea.2008.02.016).
Abstract
A method for deriving apparent activation energies, Eapp, for fatigue crack growth (FCG) is presented. It is shown how these Eapp values can be used to analyse the main underlying mechanism causing the progression of the crack. The Eapp values for fatigue crack growth in air and vacuum, and with and without a dwell are obtained for a range of Ni based superalloys for turbine disc applications. The apparent activation energies range from about zero to about 300kJ/mol. The analysis allows identification of alloys that are prone to FCG through diffusion controlled mechanisms, notably grain boundary oxidation or grain boundary creep, as well as alloys that are nearly immune to FCG by grain boundary oxidation or creep.
Text
Thermal_activation_FCG_-_Starink_&_Reed_2008.pdf
- Accepted Manuscript
More information
Published date: September 2008
Keywords:
activation energy, N18, U720Li, RR1000, nickel superalloy, fatigue crack propagation, turbine disc alloys, creep, oxidation, fractography, thermal activation, diffusion, creep-fatigue
Organisations:
Engineering Mats & Surface Engineerg Gp
Identifiers
Local EPrints ID: 50250
URI: http://eprints.soton.ac.uk/id/eprint/50250
ISSN: 0921-5093
PURE UUID: 6b350f2b-88a8-4d31-9f7e-2931fecb1890
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Date deposited: 05 Feb 2008
Last modified: 16 Mar 2024 02:44
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