DARWIN-HC:¿ A Tool to Predict Hot Corrosion of Nickel-Based Turbine Disks

Hot Corrosion of turbine engine components has been studied for many years. The underlying mechan-isms of Type I Hot Corrosion and Type II Hot Corrosion are increasingly well-understood. Nickel-based superalloys have shown strong resistance to high temperature oxidation attack and, of course, excellent high temperature strength. Modern turbine engine designs that seek to achieve better fuel efficiency in part by increasing turbine inlet temperatures are strong candidates for nickel-based superalloy turbine disk materials. As disk temperatures approach 700C, designers must consider the likelihood and effects of Type II corrosion. Type II corrosion is typically characterized by localized corrosion pitting caused by melting of sulfur-containing salts. Type II hot corrosion pits have been shown to decrease the fatigue resistance of superalloys due to initiation of fatigue cracks at hot corrosion pits. However, the rigorous analytical models and tools needed by turbine engine designers to predict Type II corrosion pit formation and fatigue life degradation due to corrosion pits are not currently available. Barron Associates, Inc. and its research partners propose to develop corrosion pitting and fatigue life models for nickel-based superalloys subjected to Type II hot corrosion. The models will be commercia-lized and made available to the research and development community.