Recrystallization of the hot isostatic pressed nickel-base superalloy FGH4096. II: Characterization and application

Recrystallization of the hot isostatic pressed nickel-base superalloy FGH4096 undergoes three characteristic periods, viz., incubation, nucleation and growth. Working temperature has a great effect on its boundary migration and nucleation. In recrystallization process, the nucleation rate is obviously accelerated with the increasing working temperature. To obtain fine grains, hot working should be carried out at the temperature of 1050–1080 °C. After two passes multiple forging, the grain size is significantly refined from 30.0 to 2.2 μm, and the refinement mechanism is found to be the repeated dynamic recrystallization (DRX) in the multiple forging process. Equiaxed-flatted gradient microstructure is obtained via the gradient temperature heat treatment (GTHT).

The equiaxed-flatted gradient microstructure obtained after GTHT.Figure optionsDownload as PowerPoint slideHighlights
► Recrystallization undergoes three periods, viz., incubation, nucleation and growth.
► The grain size is refined from 30.0 to 2.2 μm after two passes multiple forging.
► The gradient microstructure is obtained via gradient temperature heat treatment (GTHT).
► Novel gradient structure has potentials for application in turbine disc with dual properties.