Fabrication of single-crystal superalloy hollow blade based on integral ceramic mold

Abstract

The integral ceramic mold technique based on stereolithography additive manufacturing and gelcasting technology was applied to casting single-crystal (SX) superalloy parts. The fabrication process for producing alumina-based ceramic molds with kyanite additive and the resultant mold structures were investigated. The results showed that the fabricated alumina-based molds exhibited superior high-temperature mechanical performance and dimensional stability. The high-temperature mechanical performance was attributed to the addition of suitable amounts of kyanite, which led to the mullitization of the raw materials. Moreover, the volume expansion that accompanied kyanite decomposition enabled well-controlled sintering shrinkage and apparent porosity. The ceramic molds prepared with the optimal amount of kyanite exhibited favorable bending strength, creep deformation, sintering shrinkage, and apparent porosity for directional solidification of SX superalloys. Cast trials of a hollow turbine blade using CMSX-4 SX superalloy demonstrated the potential of the proposed approach for rapid-cast SX superalloy parts.