Effect of solidification interface morphologies on microstructure and solute segregation of a single crystal Ni-base superalloy

The effect of solidification interface morphologies on microstructure and solute segregation behaviour of hot corrosion-resistant single crystal Ni-base superalloy has been studied. When the liquid/solid interface morphology transforms from cellular to dendritic, the primary arm spacing and the solute segregation increase drastically, yet decrease remarkably with the increase of solidification rate in the range of dendrite solidified. The farther the primary arm spacing is, the more serious the segregation of solute may be. In the structure of coarse dendrite when the primary arm spacing reaches a maximum, a new high Cr eutectic structure with low melting point is found in front of γ/γ' eutectic.