Effect of 3Y–ZrO2 addition on the phase, mechanical, and microstructural properties of Al2O3–ZrO2 ceramics

The study examines the effect and mechanism of 3Y–ZrO₂ addition on the phase composition, microstructure, and mechanical properties of Al₂O₃–ZrO₂ ceramics. The ceramics were sintered at 1580°C for 120 min, comprising varying proportions of 20, 40, 60, and 80 wt.% of 3Y–ZrO₂. The study investigates the phase composition, phase content, microstructure, relative density, microhardness, fracture toughness, and wear rate of the ceramics. Notably, Al₂O₃–ZrO₂ ceramics demonstrated a dense surface with evenly distributed reinforcing particles in the matrix. The microhardness and wear rate of Al₂O₃–ZrO₂ ceramics declined with increased 3Y–ZrO₂ addition; in contrast, the bending strength, abrasion resistance, and fracture toughness increased with the addition of 3Y–ZrO₂. Alumina grain refinement, crack propagation inhibition, and microcrack toughening induced by tetragonal-to-monoclinic phase transformation are the primary factors influencing these changes. Meanwhile, as the content of 3Y–ZrO₂ increases, the fracture mode of Al₂O₃ shifted gradually from transgranular to intergranular, whereas ZrO₂ maintained predominantly transgranular fracture.