The Influence of Compressive Residual Stress Layers on a Hot Corrosion Process within the Gas Turbine

As the aerospace industry demands increasing efficiency and with stricter emission limits set by governing bodies, the design of the modern gas turbine engine must now cope with a range of environmental attack. As turbine entry temperatures have increased to allow for these improvements, temperatures in engine components are now in the range suitable to promote Sulphidation attack. The use of compressive residual stress layers to improve total fatigue life is a well established technique within the engineering community. By reducing the amount of surface dominated failures, components are less susceptible to transitioning to mechanical cracking. This paper will present and discuss the initial findings of high temperature corrosion-fatigue testing and the influence of compressive residual stress layers on hot corrosion behaviour. The outcome of this work will lead to the definition of the likely test conditions for assessing the role of shot peening on the high temperature corrosion-fatigue performance of a nickel based superalloy.