| Abstract Scope |
Nickel based superalloys are commonly utilised for their superior high temperature strength, particularly suited to turbine applications. Improvements in gas turbine efficiency has led to an increase in core temperatures; which, combined with a more variable operation and the ingestion of contaminants such as sea salt, can lead to the onset of environmentally assisted cracking. Shot peening, a type of cold work technique, has been successfully demonstrated to provide significant fatigue life benefit by imparting compressive residual stress into surfaces. More recently, this understanding has focussed on the beneficial plastically deformed layer imparted into the material and which co-exists as part of the shot peening process. The work presented will examine the role of shot peening as a potential palliative for environmentally assisted cracking at elevated temperatures. Predominantly, the testing has been undertaken at 550°C using a C-ring type geometry with supporting evidence obtained from higher temperature tests. |