Microstructures and mechanical properties of additively manufactured alumina ceramics with digital light processing

Digital light processing (DLP) technology has presented great potential to fabricate ceramic structures including alumina component, yet the mechanical properties of DLP-manufactured ceramics are still difficult to be guaranteed. The enhancement of mechanical properties of DLP-fabricated ceramic materials is challenging and imperative in the field of industrial application. This paper investigates the printing and heat treatment processes of additively manufactured ceramic to achieve defect-free Al2O3 ceramic with high performance. Firstly, Al2O3 ceramic slurry with a high solid content of 55 vol.% and viscosity of 6.04 Pa & BULL;s (at the shear rate of 100 s(-1)) is prepared. Then, Al2O3 ceramic is manufactured with digital light processing, debinding and sintering processes sequentially. Thirdly, the effects of sintering temperatures on the shrinkage, density, microstructure, and mechanical properties of the Al2O3 ceramics are analyzed. The shrinkage, density, and flexural strength of the sintered ceramic increase with temperature; the microhardness shows a non-monotonic trend with the increase of sintering temperature. Finally, the influence mechanism of sintering temperature on microstructures and mechanical properties of the DLP-fabricated ceramics is interpreted and discussed. The ceramic grains grow and combine to form long columnar grains during higher sintering temperatures. The density, microhardness and flexural strength of the Al2O3 ceramics sintered at 1600 degrees C are achieved 3.51 g/cm(3), 17.71 GPa and 175.8 MPa, respectively.