SOLIDIFICATION OF NICKEL-BASED SINGLE CRYSTAL SUPERALLOY BY ELECTRIC FIELD

摘要

The crystal growth of a nickel-based single crystal superalloy DD3 was researched via con- trolled directional solidification under the action of a DC electric field. The cellular or dendrite spacing of the single crystal superalloy is refined and microsegregation of alloying elements Al, Ti, Mo and W, is reduced by the electric field. The electric field decreases the interface stability and reduces the critical growth rate of the cellular-dendritic translation because of Thomson ef- fect and Joule heating. The precipitation of the γ phase is more uniform and the size of the γ’ phase is smaller with the electric field than that without the electric field.