One-step additive manufacturing of TiCp reinforced Al2O3–ZrO2 eutectic ceramics composites by laser directed energy deposition

Abstract

With the rapid and adaptable process properties, laser directed energy deposition (LDED) is increasingly becoming popular for the direct additive manufacturing of melt growth eutectic composite ceramics. In this research, LDED is used to fabricate TiCp-reinforced Al2O3–ZrO2 eutectic ceramics. The inhibitory mechanism of various ratios (0 wt % - 50 wt %) of TiCp on crack and porosity defects is investigated. In addition, a summary of the influence of TiCp on the microstructure and mechanical properties is provided. The results indicate that TiCp particles are uniformly distributed throughout the matrix, and the eutectic microstructure around TiCp exhibits an irregular eutectic transition as a result of a decrease in solidification rate. The mismatch of thermal expansion coefficient and elastic modulus between TiCp and Al2O3–ZrO2 eutectic matrix causes the cracks to be pinned and transgranular, which suppresses the cracks effectively. Meanwhile, doping TiCp particles enhances the molten pool impact and increases the molten pool temperature, which accelerates the gas escape rate, leading to the porosity decreasing from 6.37% to 0.29%. In comparison to Al2O3–ZrO2 eutectic ceramics, 50 wt% TiCp content results in the greatest flexural strength and fracture toughness, with increases of 34.18 and 13.42%, respectively. The greatest compressive strength is attained at 30 wt% TiCp doping, which is approximately 83.75% greater than eutectic ceramics.