Microstructure of an experimental Ni base superalloy under various casting conditions

▶Superheat and cooling rate effect on solidification of Ni alloy was investigated. ▶The microstructure contains γ matrix, interdendritic γ/γ′, γ′, MC, η and σ phases. ▶The Vf of σ and η phases increases as the superheat increases. ▶The Vf of σ and η phases increases as the solidification cooling rate decreases. ▶Highest cooling rate and lower superheat have the large Vf of interdendritic γ/γ′.