Effects of solid solution treatment with different cooling Ways on the microstructure and mechanical properties of a cast nickel-based alloy under the condition of VIM（vacuum induction melting）were investigated.The results reveal that with solid solution treatment at 1 210 ℃for 4hin non-vacuum heat treatment furnace and air cooling as well as spraying 1309 Dcoating on the bar

the size ofγ′phase in dendritie with the higher unifromity and 73.3%volume fraction is finer than that in as cast alloy.In addiiton

with solid solution at 1 210 ℃for 4hin non-vacuum heat treatment furnace

γ′phase particles in dendrite exhibits cubic morphology with distributed more uniformly

andγ′phase fraction reaches 74.2%

and mechanical properties are satisfied.With solid solution at 1 210 ℃for 4hours under vacuum condiiton

γ′phase particles are coarsened to spheroidization

deteriorating the mechanical properties of the alloy.