On the Effect of Environmental Exposure on Dwell Fatigue Performance of a Fine-Grained Nickel-Based Superalloy
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Springer Science and Business Media LLC
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Pedrazzini, S., Child, D., Aarholt, T., Ball, C., Dowd, M., Girling, A., Cockings, H., et al. (2018). On the Effect of Environmental Exposure on Dwell Fatigue Performance of a Fine-Grained Nickel-Based Superalloy. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 49 (9), 3908-3922. https://doi.org/10.1007/s11661-018-4752-7
The influence of sulfur contamination on the corrosion-fatigue behaviour of a polycrystalline superalloy used in aero-engines is considered. Samples tested under a variety of environmental conditions (including exposures to air, SOx gas and salt) are characterised through a suite of high-resolution characterisation methods, including transmission electron microscopy (TEM), secondary ion mass spectroscopy (nanoSIMS) and atom probe tomography (APT). The primary effect of sulfur contamination is to accelerate the crack growth rate by altering the failure mechanism. The SIMS and TEM analyses indicate Cr-Ti sulfide particle formation at grain boundaries ahead and around oxidised cracks. The atom probe tomography analysis suggests that these particles then oxidise as the crack propagates and are enveloped in chromia. The chromia is surrounded by a continuous layer of alumina within the cracks. All of the sulfur detected was confined within the particles, with no elemental segregation found at grain boundaries.
Materials for the present work were supplied by Rolls-Royce plc. Funding is acknowledged under the Rolls-Royce-EPSRC Strategic Partnership grant EPM005607/1.
Engineering and Physical Sciences Research Council (EP/M005607/1)
Engineering and Physical Sciences Research Council (EP/R00661X/1)
External DOI: https://doi.org/10.1007/s11661-018-4752-7
This record's URL: https://www.repository.cam.ac.uk/handle/1810/283534
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/