|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Microstructural Templates Consisting of Isostructural Ordered Precipitate / Disordered Matrix Combinations: Microstructural Evolution and Properties
||The Origin and Stability of Nanostructural Hierarchy in Nickel-base Superalloys
||Subhashish Meher, Larry Aagesen, Tresa M. Pollock, L. J. Carroll
|On-Site Speaker (Planned)
A combined experimental and phase-field modeling approach has been used to explore a hierarchical structure at nanoscale for enhanced coarsening resistance of ordered γ′ precipitates in an experimental, multicomponent, high-refractory nickel-base superalloy. The hierarchical microstructure formed in this alloy is composed of a γ matrix with γ′ precipitates that contain embedded, spherical γ precipitates, which do not directionally coarsen during high-temperature annealing but do delay coarsening of the larger γ′ precipitates. Chemical mapping via atom probe tomography suggests that the supersaturation of Co, Ru, and Re in the γ′ phase is the driving force for the formation of this hierarchical microstructure. Representative phase-field modeling highlights the importance of larger γ′ precipitates to promote stability of the embedded γ phase and to delay coarsening of the encompassing γ′ precipitates. These results suggest that the hierarchical material design has the potential to influence the high-temperature stability of precipitate strengthened metallic materials.