Search

In this work, we report a novel approach to fabricate titanium carbide (TiC) ceramics toughened by Y2O3introduced via chemical precipitation method. TiC ceramics with and without Y2O3addition 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 Y2O3sintered at 1600 °C, indicating that Y2O3additive 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 Y2O3pinning 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. [ABSTRACT FROM PUBLISHER]

In this research, we creatively integrate the traditional methods of liquid precursor infiltration plus in-situ precipitation with stereolithography-based 3D printing for the fabrication of Al 2 O 3 -ZrO 2 ceramics to ensure the homogeneous distribution of ZrO 2 particle in the alumina matrix. Our characterization results shows that this combination leads to the materials with significantly better performance. The Al 2 O 3 specimen is soaked in a Zr 4+ ion solution to induce infiltration, in-situ precipitation and then sintered. X-ray diffraction analysis of the thus-treated sample indicated that Al 2 O 3 was the primary phase and t-ZrO 2 was the secondary phase. Microstructural and EDS analysis showed that the ZrO 2 particles were homogeneously distributed in the Al 2 O 3 matrix, leading to inhibited grain growth. The samples soaked in solutions for different Zr 4+ concentrations and sintered both at 1450 °C and 1550 °C showed improved mechanical properties as compared to those of pure alumina. Futhermore, the sample infiltrated using the solution with a concentration of 1.5 mol/L and sintered at 1450 °C showed similar fracture toughness (4.97 MPa m 1/2 ) with the sample sintered at 1550 °C (5.06 MPa m 1/2 ) but much better hardness (20.95 Gpa) than the sample sintered at 1550 °C (19.71 GPa). Therefore, this method could not only enhance the mechanical properties via introducing the second phase, but also lowers the sintering temperature by at least 100 °C, which would be beneficial for energy conservation and leads to significant advances in the 3D printing of ceramic components. [ABSTRACT FROM AUTHOR]