Probabilistic Prediction of Location-Specific Microstructure in Turbine Disks

Thermo-mechanical processes of turbine disks have been progressively improved to meet microstructural requirements tailored for advanced, sustainable high temperature performances. However, the chemistry of typical Ni-base turbine disk alloys is very complex, and yields a variety of phases and microstructural anomalies under different thermo-mechanical heat treatments. These microstructural heterogeneities and anomalies often limit thermo-mechanical behaviors of turbine disks. The proposed Phase I program will focus on the development of multi-physics based computational tools and approaches for the prediction of HT-processing dependent microstructures, the characterization of their statistical features/anomalies and the corresponding mechanical responses, and the identification of the critical microstructural feature that may limit the performance life. A conventional Ni-base polycrystalline superalloy IN718 was chosen as a target material for the proposed work because of its most common usage for the turbine disk application and the large amount of data available from various resources. Due to the microstructural complexity of IN718, the property prediction requires rigorous numerical approaches to account for microstructural heterogeneities. The successful completion of Phase I efforts will bring microstructure-sensitive computational tools and approaches for the evaluation of differently processed IN718 disk alloys.