Influence of melt superheating time on the solidification microstructure of DD3 single crystal superalloy

Under the condition of the solidification rate and thermal gradient just ahead of solid/liquid interface unchanged, the influences of melt superheating time on the solidification microstructure of Ni base DD3 single crystal superalloy are studied. The results show that when the melt superheating temperature is 1640°C and the superheating time is increased from 30 min to 60 min, the finer dendrite structure and γ′ phase in interdendrite area are obtained, but the solidification microstructure is coarsened when the superheating time is 90 min; When the melt superheating temperature is 1780°C, with the increase of superheating time from 30 min to 60 min, the primary arm spacing and the size of γ′ phase in interdendrite area are increased, while the morphology of γ′ phase tends to be irregular.