Mechanical properties of TiC reinforced MgO–ZrO₂ composites via spark plasma sintering

We develop the MgO–ZrO₂–TiC (MSZ-TiC) composite for improving the mechanical properties. To increase the mechanical hardness, spark plasma sintering technique was used, enabling rapid heating and subsequent quenching for the stabilization of tetragonal zirconia as well as the formation of the composites. Titanium carbide was applied as reinforcing material to improve the fracture toughness. Also, effect of the sintering temperature on phase evolution of the composite is investigated; with increasing sintering temperature, the monoclinic ZrO₂ (m-ZrO₂) gradually transforms to tetragonal ZrO₂ (t-ZrO₂), while maintaining the TiC structure. Combined with material characterization, mechanical properties depending on ZrO₂ phase in MSZ-TiC are discussed. As a result, increased hardness (16.3 GPa) and fracture toughness (5.2 MPa m^1/2) were observed from optimized MSZ-TiC sintered at 1400 °C mainly due to phase transformation of ZrO₂. This work can provide an engineering strategy to improve the mechanical properties of ZrO₂ based composites, which can be widely applied for industrial application.