Complex shaped Al₂O₃/YAG/ZrO₂ eutectic ceramics with excellent high temperature mechanical properties printed by vat photopolymerization

Directionally solidified oxide eutectic ceramics exhibit excellent performances at both room and high temperatures due to strong phase interface binding, which determines broad application prospects in the field of ultra-high temperature structural components. However, oxide eutectic ceramics prepared by current directional solidification techniques are unable to simultaneously possess large volumes, complex shapes, and uniformly fine eutectic structures. In this study, complex shaped Al₂O₃/YAG/ZrO₂ eutectic ceramic hollow guide blades with nearly full relative density and uniformly fine eutectic microstructure were successfully prepared for the first time, utilizing a combination of laser floating zone melting, vat photopolymerization 3D printing and hot isostatic pressing. Sintered eutectic ceramics with fully closed porosity achieving a relative density of 91.97 ± 1.25 % were obtained by pressureless sintering at 1670℃ for 2 h. Al₂O₃/YAG/ZrO₂ sintered eutectic ceramics with a relative density of 99.27 ± 0.22 % were obtained by hot isostatic pressing at 1550℃ with 200 MPa for 60 min. The sintered highly densed eutectic ceramic exhibited a bending strength of 352.99 ± 39.97 MPa at room temperature. This bending strength can remain a value of 299.38 MPa at 1500°C, which is corresponding to a high strength retention rate of 84.81 %. Additionally, the hardness was 19.10 ± 0.69 GPa and the fracture toughness was 2.22 ± 0.21 MPa·m^1/2. This work offers a novel solution for the preparation of complex shaped oxide eutectic ceramic components.