Fig. 1. Internal structure of turbine blades. (a) Development trend of turbine blade internal structure^[5]; (b) typical gas-cooled structure inside gas turbine blades^[6]

Fig. 2. Design of ceramic core/shell for superalloy airfoil^[9]. (a) Ceramic core for complex internal cooling passages; (b) cross-section of integrally cored ceramic mold; (c) profile of integrally cored ceramic mold

Fig. 3. Preparation of ceramic core/shell by SLS process

Fig. 4. Al₂O₃-SiO₂ ceramic parts prepared by SLS^[17]

Fig. 5. Surface morphology of alumina ceramic parts prepared by SLS. (a) Before debinding; (b) after debinding

Fig. 6. Two main process routes for preparation of ceramic core/shell by SLA process

Fig. 7. Effect of particle size distribution on segregation in layers of green body fabricated by SLA process^[66].(a) Regions representing segregation and no segregation in layers; (b) bimodal powder; (c) coarse powder

Fig. 8. Green bodies under different drying conditions^[44]. (a) Air drying; (b) freeze drying

Fig. 9. Ceramic shell/core fabricated by SLA＋gel casting^[77]. (a) CAD model of simplified ceramic impingement hole cores (CIHCs); (b) CIHCs prototype fabricated by SLA process; (c) CIHCs mold; (d) cross-section of double wall blade; (e) deformation of double-wall ceramic core from finite element simulation; (f) cross-section of fabricated metal double-wall blade

Fig. 10. Integrally cored ceramic mold for turbine airfoil with complex internal hollow structure^[9]. (a) Three-dimensional model; (b) green body; (c) sintered body without any cracks