Compressive strain-dependent bending strength property of Al2O3–ZrO2 (1.5 mol% Y2O3) composites performance by HIP

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 (ɛ) increased from 0.56 to 1.18 (10−3) as the t-ZrO2 content increased too.The HREM interface study conducted along the [0 0 0 1]Al2O3||[0 0 1]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 α-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¯ 0) along [1¯ 1 0] and [1¯ 1¯ 0] crystallographic directions, respectively; these planes are arrested by the (1 0 1¯ 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.