In-situ synthesis of high-performance Al2O3-based ceramic cores reinforced with core-shell structures

Abstract

The complex structure of the ceramic cores is key to the preparation of an aero-engine hollow blade with excellent cooling performance. The traditional methods such as hot-press moulding are difficult to prepare complex-structured ceramic cores, and 3D printing technology provides a new idea for the preparation of complex-structured ceramic cores. Using SiO2 and Y2O3 as mineralizers in Al2O3-based ceramic cores, high-performance ceramic cores with a core-shell structure was successfully prepared by 3D printing. Additionally, the changes in microstructure and properties at different sintering temperatures were studied. The results showed that with an increase in the sintering temperature, a core-shell structure with Y2Si2O7 as the shell and Y2O3 as the core was formed, and the reinforced phases such as mullite were generated at the same time. The formation of core-shell particles suppressed the energy loss of cracks. The generation of the liquid phase led to the tight bonding of the Al2O3 particles. The synergistic effects of the core-shell structures and the reinforced phases enhanced the flexural strength. When the sintering temperature was 1380 °C, the comprehensive performance met the application requirements of the ceramic cores, and the flexural strength and porosity were 19.3 MPa (at 1500 °C) and 30.5%, respectively. The 3D-printed ceramic core by low-temperature sintering with a core-shell structure was successfully prepared, which promoted the wider application of DLP-3D printed ceramic cores technology in the field of precision casting. This is expected to reduce the energy consumption during the sintering process and promote the production of high-performance complex-structured ceramic cores.