Nanometric powders and sintered ceramics of Al2O3-ZrO2 (1.5 mol% Y2O3) prepared by hot isostatic pressing HIP have been studied. A detailed crystallographic study has been performed through X-ray diffraction, Williamson-Hall method, Rietveld method and high-resolution electron microscopy HREM analysis. The crystallographic structure data, such as domain size, lattice parameters, wt% phase, and micro-strain direction have been obtained using Rietveld refinement and Williamson-Hall methods. The results revealed that the compressive strain (E) increased from 0.56 to 1.18 (10(-3)) as the t-ZrO2 content increased too. The HREM interface study conducted along the [0001]Al2O3 parallel to[001]ZrO2 zone axis revealed a micro-strain lattice distortion accumulated at the grain boundary due to the ZrO2 martensitic phase transformation on cooling, t-ZrO2 grains coalescence and to the grain growth of alpha-Al2O3 which cause elongated tetragonal crystals. Micro-strain lattice distortion is adjusted by the shear displacements of the planes (1 1 0) and (1 (1) over bar 0) along [(1) over bar1 0] and [(1) over bar (1) over bar 0] crystallographic directions, respectively; these planes are arrested by the (1 0 (1) over bar 0) alumina plane. In this case, semi-coherent interfaces were observed along the grain boundary. It is verified that the bending strength increased in connection with the strain accumulation and amount of tetragonal structure. (C) 2008 Elsevier B.V. All rights reserved.