Effect of Hot Deformation on PPB Precipitations and Microstructure in P/M Superalloy FGH96

Abstract

HIPed FGH96 superalloy prepared by AA powder was used as the research object, and the PPB precipitations and microstructures before and after different hot deformations were studied. The results show that PPB precipitates with circular distribution can be seen in HIPed FGH96 superalloy, and the coarse strip prime γ′ phase with circular chain distribution is one of the main characters of PPB. After hot deformation, the PPB in FGH96 superalloy is deformed and broken, the recrystallization grains are refined and twisted, and the grain misorientation becomes smaller. With the increase of deformation temperature and hot deformation, and the decrease of deformation rate, the deformation and fragmentation of PPB precipitates are more significant, the size of the primary residual γ′ phase becomes smaller, and the volume becomes less. The increase of deformation temperature and hot deformation, and the decrease of deformation rate are beneficial to reduce or even eliminate PPB precipitations.

Keywords

• AA powders
• FGH96
• prior particle boundary (PPB)
• hot deformation
• coarse γ′ phase