Microstructural analysis and mechanical property assessment have been carried out on hot isostatically pressed (HIPped) and heat treated samples of RR 1000 powder to assess Net Shape HIPping as a process-route for aero engine components. HIPping led to (Hf,Zr)-rich oxides and carbides on prior particle boundaries (PPBs) which could be coarsened, but not eliminated by changing the HIP procedure. HIPping above the γ′ solvus resulted in coarser grains with serrated boundaries and in the formation of irregular-shaped secondary γ′ and fan-type γ-γ′ structures. Factors which influence the growth and morphology of γ′ particles are considered and it is shown that particle impingement dominates in the formation of irregular γ′ during continuous cooling from supersolvus. Solution treatment near the HIPping temperature led to thermally induced pores (TIP) but lower temperatures avoided TIP and changed the γ′ size, distribution and morphology giving a large volume fraction of finer cuboidal secondary γ′ and medium-sized spherical tertiary γ′.
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