Fine grained Al2O3-ZrO2 (Y2O3) ceramics by controlled crystallization of amorphous phase

It is classic to prepare nanoceramics by crystallization of amorphous solids; however, this method was seldom reported in the classic system of Al2O3-ZrO2. In present work, fine grained Al2O3-ZrO2 (Y2O3) ceramics were obtained through controlled crystallization of dense amorphous bulks by heat treatment. Phase composition, microstructure and mechanical property were investigated during heat treatment. Crystallization and densification were almost completed after heat treatment at 1400 °C for 2 h with relative density of 98.5%, and as-prepared sample exhibited homogenous mixture of Al2O3 and ZrO2 grains at about 440 nm. The fine grained ceramic exhibited high hardness of 15.5 GPa and fracture toughness of 5.2 MPa m1/2. This work may provide new guidance for preparing AZY nanoceramics through crystallization of amorphous phase in both experiment and theory.