Laser powder bed fusion fabrication of TiB2-Modified Al2O3-ZrO2 eutectic ceramics: Microstructure evolution and mechanical properties

The present study systematically investigates the formability, microstructural evolution, and mechanical behavior of Al2O3-ZrO2 eutectic ceramics doped with TiB2 in the range of 0 wt % to 10 wt % via laser powder bed fusion (L-PBF). The results demonstrate that the incorporation of TiB2 has a significant influence on the quality of the samples, leading to the attainment of a low surface roughness of 5.5 mu m and the absence of surface transverse cracks. Furthermore, the Transmission Electron Microscope (TEM) analysis reveals the existence of a ZrTi phase with a hexagonal structure located between TiB2 and the base material, which can be attributed to the reaction of TiB2 with ZrO2. Additionally, the introduction of TiB2 facilitates the refinement of microstructure through pegging and heterogeneous nucleation, ultimately enhancing the hardness and fracture toughness of the eutectic composite material through second-phase strengthening. The optimal Vickers hardness and fracture toughness are observed to be 2000 HV and 5.97 MPa m1/2, respectively. Overall, the insights obtained from this study provide a solid foundation for the practical utilization of Al2O3-ZrO2 eutectic composites modified with TiB2, opening up new avenues for the development of high-performance crack free ceramic materials with superior mechanical properties.