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Ceramic cores are important in the fabrication of superalloy hollow blades, which are increasingly characterized by intricate internal cavity channels. This complexity poses significant challenges to traditional manufacturing processes. The vat photopolymerization 3D printing technology provides a new choice for ceramic cores with complex structures. However, the lamellar structure of the vat photopolymerization 3D printed ceramic cores leads to the anisotropy. Meanwhile, the low strength and high shrinkage of ceramic cores restrict their industrial application. In this study, using Al2O3 powder as the main material, the effects of zircon content on the sintering shrinkage, open porosity, flexural strength, and other properties of Al2O3-based ceramic cores were studied to address the aforementioned issues. The influencing mechanism of zircon distribution on sintering shrinkage was analyzed, and the strengthening mechanism of mullite on ceramic cores was discussed from both thermodynamics and dynamics aspects. Through the comprehensive evaluation of ceramic core properties, the Al2O3-based ceramic core with 15vol.% zircon exhibites the optimal performance. Compared with the core samples without zirconium addition, the flexural strength of the Al2O3-based ceramic core with 15vol.% zircon increases from 14.80 MPa to 61.54 MPa at 25 °C, an increase of 315.8%; and from 4.91 MPa to 11.59 MPa at 1,500 °C, an increase of 136.0%. The shrinkage in the Z-axis is reduced by 21%, which better weakens the anisotropy of the shrinkage of 3D printed Al2O3-based ceramic cores. ZrO2 phase and mullite phase are formed by zircon, which improve the comprehensive properties of Al2O3-based ceramic cores. The successful 3D printing of high-performance Al2O3-based ceramic cores via vat photopolymerization has promoted its industrial application for fabricating ceramic cores with complex structures.
Qu et al. (Mon,) studied this question.