Experimental and simulation on the grain growth of P/M nickel-base superalloy during the heat treatment process

The heat treatment experiments of γ-grain growth were conducted to achieve grain size control for manufacturing dual-property turbine disks in a powder metallurgy nickel-base superalloy. The relationships between grain size and solution temperature, between grain size and holding time were obtained. A simulation model was built to investigate the grain growth in different regions of the disk subjected to the gradient heat treatment. The dual microstructure combining the fine grain bore and coarse grain rim could be achieved by controlling the treating temperatures. Under a suitable treating condition, the grain grade in the bore region of the disk reached 9–10, while in the rim region reached 5.5–6.