Thermal activation of fatigue crack growth: analysing the mechanisms of fatigue crack propagation in superalloys

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), 279-289. (doi:10.1016/j.msea.2008.02.016).


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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.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1016/j.msea.2008.02.016
ISSNs: 0921-5093 (print)
Related URLs:
Keywords: activation energy, N18, U720Li, RR1000, nickel superalloy, fatigue crack propagation, turbine disc alloys, creep, oxidation, fractography, thermal activation, diffusion, creep-fatigue
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TL Motor vehicles. Aeronautics. Astronautics
T Technology > TN Mining engineering. Metallurgy
Divisions : University Structure - Pre August 2011 > School of Engineering Sciences > Engineering Materials & Surface Engineering
ePrint ID: 50250
Accepted Date and Publication Date:
September 2008Published
Date Deposited: 05 Feb 2008
Last Modified: 31 Mar 2016 12:27

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