Alumina-silica based ceramic cores prepared by additive manufacturing-hot press injection composite molding

Ceramic cores are key transfer components for single crystal superalloy hollow turbine blades in aeroengines. To address the insufficient impact resistance of the fine structures in ceramic cores, this work innovatively adopts photocuring additive manufacturing to develop a composite-formed alumina-silica based ceramic core. Dense α-Al2O3 phase ceramic fine structural components are produced, with dimensional accuracy and three-point bending strength reaching ±0.003 mm and 314 MPa, respectively, exhibiting excellent impact resistance. The main body of the ceramic core, which encapsulates the alumina-based ceramic components via hot injection molding, has a bending strength of 12 MPa and an apparent porosity of 29.5%, ensuring favorable collapsibility and leachability. The relationship between the separation gap width of the heterogeneous alumina-silica material interface and the thermal expansion coefficient, shrinkage rate, and elastic modulus of two materials is established. Micro-texture design on the surface of additively manufactured alumina-based ceramic components is adopted to form an interlocking alumina-silica interface microstructure on the composite-formed ceramic core, which improves the physical bonding strength of the heterogeneous interface and effectively compensates for interfacial separation during thermal processes. Basic casting verification of single-crystal hollow turbine blades is achieved using the composite-formed alumina-silica based ceramic core, with high dimensional conformity of process holes and no excess metal in the inner cavity. It demonstrates broad application prospects in the precision casting of superalloy blades for aeroengines.