Effect of the Al2O3 content on the mechanical properties and microstructure of 3Y-TZP ceramics for dental applications

Abstract

Alumina-reinforced zirconia composites containing 0 to 30 vol% of alumina were fabricated by sintering at 1550 °C for 2 h in air. The effect of the Al2O3 content on the mechanical properties and microstructure of 3Y-TZP ceramics was investigated. Al2O3 acted as an inhibitor of the grain growth of 3Y-TZP. As the alumina content increased, the fracture mode changed gradually from the transgranular mode to the intergranular mode and the Young’s modulus and hardness increased. The biaxial flexural strength also showed a slight increase with an increase in Al2O3 content, due to the grain size refinement of the ZrO2 matrix, while the fracture toughness, which was investigated by the SEVNB method, showed a contrary tendency. The decrement of the fracture toughness can be explained by the increase in the critical transformation stress, the decrease in the volume fraction of the transformable t-ZrO2 and the increase in the tensile residual stress.