Interface Morphologies and Microstructure of a Single Crystal Superalloy under High Thermal Gradient Directional Solidification

摘要

The interface morphologies single crystal superalloys CMSX-2 has been studied over a range of cooling rate with large variations in withdrawal speed in directional solidification. The superfine cellular structure was obtained under both high thermal gradient up to 1000K/cm and fast withdrawal rate up to 1 mm/sec. The high rate directional solidification results in reduction in primary and secondary dendrite arm spacing, refinement of λ′ phase, reduced microsegregation of alloying elements and smaller size of γ-γ′ eutectics.