Microstructural evolution and mechanical properties of nano-ATZ ceramics by solid solution precipitation

Alumina toughened zirconia (ATZ) nanoceramics accompanied with high-strength, high-toughness and high-hardness were prepared by in-situ nanoprecipitation from using solid solution micro-powders. The submicron-sized Al2O3 (∼445 nm) and ZrO2 (∼361 nm) grains contained low-density precipitated nano-ZrO2 (∼35 nm) and nano-Y4Al2O9 (YAM, ∼87 nm) particles, respectively, making high-performance nano-ATZ ceramics with ultrafine intracrystalline nanostructure yet achieved. There was a parallel or eutectic lattice orientation relationship between the submicrocrystals and its internal nanoparticles of their crystal planes, which is very conducive to the improvement of the mechanical properties of nano-ATZ ceramics. The fracture toughness and hardness of 30wt%Al2O3/70wt%ZrO2(3 mol%Y2O3) can reach up to 5.68 ± 0.17 MPa m1/2 (single-edge V-notched beam method, SEVNB) and 16.32 ± 0.45 GPa, respectively, which are improved by ∼25% and ∼20% compared with those of 3Y-TZP ceramics. Therefore, this method can be used to prepare nano-ATZ ceramics contained ultrafine nanoparticles and uniform distribution of Al2O3 phases.