Tailoring LPBF Process Strategies for Al₂O₃-based Ceramics: From Single Tracks to Bulk Samples Fabrication

Alumina (Al2O₃) based materials have a poor laser absorptivity, high melting point, and low thermal conductivity, making them challenging materials to be processed via Laser Powder Bed Fusion (L-PBF). This study investigates the optimization of L-PBF process parameters for Al2O3 ceramics starting from single scan tracks (SST) to bulk samples. Initially, SSTs were produced using pure Al2O3, Al2O3-ZrO2 eutectic, evaluating the addition of graphene as an absorption enhancer. The influence of linear energy density (LED) on track shape (width, depth), stability, and continuity was analysed, and the results revealed that zirconia and graphene, under high LED conditions, significantly improved melt pool behaviour. Subsequently, bulk samples were fabricated with different strategies to assess the surface quality, defect formation, and densification. The process parameters, such as laser power and scanning speed, were optimized. The results show that the use of a optimized 67° scanning strategy significantly improves printability while reducing thermal cracking and increasing density. This study provides valuable insights into tailoring L-PBF process parameters for Al2O3 based ceramics to establish a pathway towards the reliable printing of dense and crack-free Al2O3 ceramics suitable for high performance applications.