Effect of adding Y2O3 on structural and mechanical properties of Al2O3–ZrO2 ceramics

Abstract The effects of adding 1–8 wt% Y 2 O 3 on phase formation and fracture toughness of Al 2 O 3 – x ZrO 2 –Y 2 O 3 (AZY) ceramics were studied. Phase formations of the samples were characterized by the X-ray diffraction (XRD) technique. It was found that the major phase was rhombohedral-Al 2 O 3 , while the minor phase consisted of the monoclinic-ZrO 2 , tetragonal-ZrO 2 and monoclinic-Y 2 O 3 . It was found that Y 2 O 3 contents did not clearly influence grain shape of AZY ceramics. The results obtained from the microhardness test could be used to evaluate the fracture toughness. It was found that the smaller grains had high fracture toughness. The maximum fracture toughness of 4.827 MPa m 1/2 was obtained from 4 wt% Y 2 O 3 . Refinement of lattice parameters using Rietveld analysis revealed the quantitative phases of AZY ceramics. This shows that under adding Y 2 O 3 conditions the proportion of tetragonal-ZrO 2 phase plays an important role for the mechanical properties of AZY ceramics.