Preparation and Mechanical Properties of 25vol%YAG-Al_2O_3 Nanocomposites

vol%YAG-Al2O3 nanocomposite powders were prepared by the co-precipitaion method from ytrium nitrate and aluminium nitrate as starting materials. The XRD pattern for the prepared powder calcined at 1300 ℃ for 1h shows well-defined peaks whose positions are almost identical to those of stoichometic YAG and α-Al2O3. The powder compacts by hot-press sintering for 0.5 h at 1400 ℃ and 300MPa reached a density close to the thoretical, while the normally reported hot-press sintering temperature for YAG-Al2O3 composites is 1600 ℃. The bending strength and fracture toughness of prepared 25vol%YAG-Al2O3 nanocomposite were 612 MPa and 4.54 MPa·m-1/2, respectively, which are much higher than those of monolithic Al2O3 and monolithic YAG, as well as higher than those reported in other studies for YAG-Al2O3 composites. Microstructure studies found that the nano-YAG particles were mainly located within the Al2O3 grains.