Effect of NaCl and SO2on the stress corrosion cracking of CMSX-4 at 550°C

Autor: Duarte Martinez, F., Syed, A., Dawson, K., Tatlock, G. J., Morar, N.I., Kothari, M., Tang, C., Leggett, J., Mason-Flucke, J.C., Gibson, G., Nicholls, J.R., Gray, S., Castelluccio, G.M.
Zdroj: Materials at High Temperatures; July 2023, Vol. 40 Issue: 4 p283-295, 13p
Abstrakt: ABSTRACTIn the pursuit of more efficient gas turbine engines, components are required to operate for longer times at elevated temperatures. This increased time in service, together with a complex loading regime, can expose the material to environmental attack. This work has demonstrated that the interaction of stress, NaCl and a sulphur-containing environment is critical to cause crack initiation in the early stages of the exposure and accelerated corrosion rates in CMSX-4 at 550°C. The effect of having small concentrations of moisture in the gaseous environment or as water crystallisation in the salt is still to be investigated. A working hypothesis is that the interaction of alkali chlorides with a sulphur-containing atmosphere is the trigger to a self-sustaining cycle where metal chloride formation, vaporisation and oxidation lead to high amounts of hydrogen injection in a rapid manner and, therefore, hydrogen embrittlement.
Databáze: Supplemental Index