Qiangguo Jiang

Effects of Y2O3 on the densification and fracture toughness of SPS-sintered TiC

Abstract In this work, we report a novel approach to fabricate titanium carbide (TiC) ceramics toughened by Y2O3 introduced via chemical precipitation method. TiC ceramics with and without Y2O3 addition were consolidated by SPS, and the densification, microstructure and fracture toughness were investigated. Compared to the additive-free counterpart, improved density and finer grain microstructure were found for TiC ceramics with Y2O3 sintered at 1600 °C, indicating that Y2O3 additive homogeneously scattered in TiC matrix could not only improve the density but also inhibit grain growth. In addition, the grain boundary was strengthened due to Y2O3 pinning in grain boundary, leading to a fracture behaviour transformation from intergranular type to the mixed mode of intergranular and transgranular fracture. Because of the improved density and strengthened grain boundary, the fracture toughness increased from 4.3 to 5.3 MPa·m1/2, which is improved by ~23% compared with that of additive-free TiC sample.

Piezoelectric array for transducer application using additive manufacturing

Piezoelectric ceramic and the corresponding array are widely used in energy harvesting and ultrasonic application for the capabilities of converting compressive/tensile stresses to an electric charge, or vice versa. However, the need for a complex geometry of array is a major technical challenge for further application. To enable the fabrication of piezoelectric ceramics, additive manufacturing (AM) processes (3D printing technology) is expect. In this study, we propose a Mask-Image-Projection-based Stereolithography (MIP-SL) technology to print piezoelectric-composite slurry with BaTiO3 particles into different arrays. After post-process, the printed arrays display piezoelectric properties that can be used in ultrasonic application.