The effect of salt composition on the stress-free and corrosion-fatigue performance of a fine-grained nickel-based superalloy. (15th April 2022)

• Record Type: Journal Article
• Authors: Hendery, M.L.; Whittaker, M.T.; Cockings, B.J.; Mignanelli, P.M.
• Is Part Of: Corrosion science. Volume 198(2022)
• Publication Date: 2022-04-15
• Subjects: Molten salts -- Nickel -- Superalloys -- Corrosion fatigue -- Sulphidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110113
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: This paper describes work to study hot corrosion damage in the nickel-based gas turbine alloy RR1000 coated with various salts at 600 °C. Interest in type-II hot corrosion on the fatigue resistance of gas turbine alloys has increased to minimise power/thermal inefficiencies. Stress-free corrosion demonstrated a greater impact of sulphate (versus chloride) on maximum pit depth, a key influencing factor of fatigue lives. In corrosion-fatigue testing, at low stresses sulphate was shown to be more influential of fatigue life. At high stresses, the presence of greater crack initiation sites, reduced initiation lives and cracked oxide suggests chlorine influenced the crack-initiation behaviour. Highlights: The first instance of the effect of salt composition on the type II hot corrosion of a nickel-based superalloy at 600 °C. Provides a new insight into the effects of chloride and sulphate-based species on stress-free corrosion and corrosion-fatigue. An interesting change in dominating mechanism was observed above and below a 'threshold' stress.