This research is about design of microstructures in superalloy structures that exhibit superior mechanical properties through grain boundary engineering. The approach of this research will be to develop and link process models, capable of producing microstructures with distinct grain boundary characteristics, with behavior models, capable of determining the fatigue life based on the microstructure. Through physics-based approaches, a process map will relate the hot deformation parameters for Nickel-based superalloys to the formation of distinct grain boundaries and microstructures. Microstructures that produce superior properties will be identified through inverse fatigue modeling and fabricated in bulk components. The validation of desired mechanical properties and mechanisms for achieving strengthening at distinct boundaries will be identified through novel in situ loading experiments coupled with strain field measurements and orientation mapping.
If successful, the benefits of this research will include the design of microstructures in bulk engineering materials that exhibit superior and tailorable mechanical properties, thus producing an increase in safety, performance, and energy efficiency of components for gas turbine engine applications. More generally, the fundamental science will enable: (a) an identification of the types of microstructures that produce advances in fatigue life, (b) an understanding of the strengthening mechanisms of these distinct grain boundaries, and (c) process maps to achieve such structures. Each of the aforementioned items will enable designs of microstructures in a wide class of materials and components that exhibit superior mechanical behavior. The broader impact of this research is four-fold: (i.) a materials camp for high school science teachers, (ii.) inclusion of women and underrepresented groups, (iii.) open and wide-spread dissemination through HUB technology, and (iv.) industrial interaction including technology transfer.
