Abstract
An alumina ceramic turbine rotor with both large volume (90mm in diameter and 20mm in height) and sub-millimeter geometry (0.42mm at the blade tip with curvature) was successfully prepared by using various manufacturing approaches. Polyjetting and computer numerical control (CNC) machining were respectively adopted to fabricate an integral sacrificial polymeric mold and a separable aluminum mold for the tailored gelcasting process, whereas selective laser sintering (SLS) was used to directly fabricate the turbine rotor by laser sintering the alumina and epoxy powders followed by liquid phase sintering in furnace. A series of experimental studies on these three rotor-forming routes were performed throughout the process. For the green rotor, the alumina slurry preparation, specific drying strategy and microstructure of the green part were presented and compared. For the sintered rotor, comparisons in terms of surface roughness, microstructure, mechanical properties and blade contour deformation were conducted. Finally, the most suitable method to fabricate the complex-shaped alumina rotor with the best performances was suggested.