Quantitative characterization of defects in stereolithographic additive manufactured ceramic using X-ray computed tomography

Ceramics have been widely fabricated by additive manufacturing (AM). Compared to conventional technologies, the strength of additive manufactured ceramic is relatively low owing to the formation of defects during manufacturing process. These defects have significant effects on the microstructure and mechanical properties of additive manufactured ceramics. However, systematic research on defects, including defect geometrical features, quantitative statistics, and formation mechanism, as well as the intrinsic relationship with mechanical properties, need to be studied in depth. In this work, Al₂O₃ ceramics were prepared from photosensitive slurries with different solid loadings by using stereolithographic (SL) additive manufacturing. The defects, including their sizes and distributions, in both green and sintered bodies were investigated by using scanning electron microscopy (SEM) and X-ray computed tomography (X-CT). Geometrical features and quantitative statistics of the defects were evaluated and discussed to reveal their formation mechanism. Moreover, the intrinsic relationship between defects and mechanical properties of the additive manufactured ceramic was revealed. This study can give some fundamental understanding of the defects in additive manufactured ceramics.