Abstract
Effects of TiC and three kinds of ZrO2(unstable, 2mol%Y2O3 doped, 3mol%Y2O3 doped) dispersions on the microstructure, fracture strength and toughness were investigated for Al2O3/TiC/ZrO2 composites. These composites were fabricated by hot-pressing the mixture of Al2O3, TiC and ZrO2 powders. X-ray diffraction analyses revealed that all composites were composed of α-Al2O3, TiC, t-ZrO2 and m-ZrO2, and another reacting phases were not detected. Transmission electron microscopic observation indicated that ZrO2 particles were located mainly at the grain boundaries of Al2O3 matrix and most of TiC particles were homogeneously dispersed not only at the grain boundaries of Al2O3 but also within Al2O3 and ZrO2 grains. The fracture strength and toughness of these composites were greatly enhanced by incorporating the TiC and ZrO2 particles. The strengthening and toughening mechanisms of Al2O3/TiC/ZrO2 composites were discussed.
