Mechanical behaviors of ZrO₂-Al₂O₃ ceramic composites with Y₂O₃ as stabilizer

The ZrO₂-Al₂O₃ ceramic composites were prepared by appropriate techniques with commercial ZrO₂ and Al₂O₃ powders as raw materials and Y₂O₃ as stabilizer. The results indicate that with the introduction of Al₂O₃ into the ZrO₂ matrix where the quantity of additive Y₂O₃ is 3.5% (mole fraction), the growth of ZrO₂ grains is efficiently inhibited, which helps the ZrO₂ grains exist in a metastable tetragonal manner; thus higher strength and toughness are acquired. When the content of alumina is 20% (mass fraction), the bending strength and fracture toughness of the composites are 676.7 MPa and 10 Mpa·m^1/2 respectively, the mechanical behaviors are close to those prepared with ZrO₂ and Al₂O₃ powders synthesized through wet chemical approach. The mechanical behaviors of the composites are well improved owing to the dispersion toughening of alumina grains and phase transformation toughening of zirconia grains.