|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||O-24: Coarsening, Dissolution and Re-precipitation in Multimodal Ni Superalloys: An In-situ Study
||Muhammad Awais, Jan Ilavsky, James Coakley
|On-Site Speaker (Planned)
Ni superalloys that operate at intermediate temperatures in gas-turbines are heat-treated to possess a multimodal gamma-prime size distribution. Deducing the influence of the nanoscale precipitates on mechanical properties within the intermediate temperature range is inherently difficult, where coarsening and dissolution of the nanoscale precipitates occurs, and re-precipitation may occur on cooling. Thus the microstructure examined by microscopy may not be representative of the microstructure at elevated temperature. It is similarly difficult to deduce precipitate evolution by in-situ small angle x-ray scattering (SAXS) due to the multiple scattering contributions that form the spectra. Finally, the similar lattice parameters of the different gamma-prime size distributions produce overlaying diffraction peaks, making in-situ wide angle x-ray scattering (WAXS) analysis non-trivial. We present combined in-situ SAXS/WAXS during heating, thermal holds and cooling, along with complementary microscopy, to address the individual technique shortcomings applied to the study of precipitation, dissolution and coarsening of multimodal superalloys.
||High-Temperature Materials, Phase Transformations, Copper / Nickel / Cobalt