Investigation of macroscopic defects of silicon carbide ceramics by stereolithography additive manufacturing

The additive manufacturing process offers a solution for fabricating complex hollow structures that are challenging to realize through traditional ceramic preparation methods. However, defects are often inevitable during the additive manufacturing process. In this study, silicon carbide ceramics with complex hollow structures are prepared using the stereolithography (SLA) additive manufacturing process. Industrial computed tomography (CT) non-destructive testing techniques are employed to observe and analyze macroscopic defects, such as cracks. The initiation and propagation mechanisms of cracks are investigated, and the influence of structural features on crack propagation is explored. The results indicate that printing corners and holes in the component are weak regions prone to stress concentration, which can lead to crack formation or further cracking. Therefore, particular attention should be paid to the printing process and the removal of residual powder. Through process optimization such as structure optimization and printing speed, especially the optimization of speed gradient in weak areas, it is helpful to avoid the occurrence of defects such as cracks.