Title:  Characterization of a Nickel-base Superalloy through Electrical Resistivity-Microstructure Relationships Facilitated by Small Angle Scattering

Abstract: Nickel-base superalloys are used in the hot sections of gas turbine engines due to their excellent high temperature strength and creep resistance. These high temperature mechanical properties are induced in the superalloy engine components by forming nanometer scale precipitate phases within the material via heat treatment. The precipitate microstructure continues to evolve with thermal exposure, resulting in evolving mechanical properties during service as well as variability during component fabrication. Electrical resistivity testing is sensitive to certain microstructural changes that occur during the precipitation process, such as precipitate nucleation, solute removal, and increases in dislocation density. This project quantifies the effects of the precipitate microstructure on the electrical response of Waspaloy (a polycrystalline nickel-base superalloy used in disc rotors) through DC electrical resistivity testing and a variety of volumetric scattering experiments. The microstructural models created in this project could eventually allow for the electrical resistivity of the material to be used as a non-destructive test for monitoring the precipitate microstructure (and thus the mechanical properties) of the engine components. Such non-destructive testing will be useful for monitoring the mechanical properties of these components during service and also for minimizing component variability during fabrication.