Stereolithography 3D printing of ceramic cores for hollow aeroengine turbine blades

• The thrust-to-weight ratio of aeroengines is largely influenced by the turbine inlet temperature. This places strict requirements on the performance of the turbine blades at high operating temperatures. To reduce the operating temperature of the blades, complex internal cooling structures are required. However, traditional techniques for manufacturing the ceramic cores used to fabricate hollow turbine blades are unsuitable for producing such complex structures. In this work, we introduce the high-performance stereolithography 3D printing (SLA-3DP) method for preparing double-walled ceramic cores suitable for use in the fabrication of single-crystal hollow turbine blades. We believe that our study makes a significant contribution to the literature because we systematically studied the effect of SLA-3DP process parameters on the microstructure, cracking, bending strength, shrinkage, and porosity of the sintered cores. Ceramic cores with complex double-walled hollow cavity structures are required for fabricating high-performance aeroengine turbine blades for fifth- and higher-generation fighter aircrafts. However, conventional approaches for ceramic core fabrication are unsuitable for producing such complex structures, which has hampered the innovation and application of hollow turbine blades. Herein, a high-performance stereolithography 3D printing (SLA-3DP) method is introduced based on digital light processing to fabricate complex ceramic cores with 60 vol% solid loading. A ceramic suspension was prepared with excellent rheological and photopolymerization properties and the SLA-3DP processing parameters were optimized based on a systematic study of the microstructure, cracking, bending strength, shrinkage, and porosity of the sintered cores. Based on the systematic characterization of high-throughput samples, an evaluation and prediction system was established for the microstructure, properties, and defect analysis of SLA-3DP ceramic cores. Finally, double-walled ceramic cores and cast single-crystal hollow turbine blades were successfully prepared. The performance data and process parameters of SLA-3DP ceramic core obtained in this work could predict and guide the selection of the most effective process parameters.