Y-TZP Ceramics with Tailored Toughness

Authors: B. Basu, J. Vleugels and O. Van Der Biest, Key Engineering Materials Vols. 206-213 (2002) pp. 1185-1188

Abstract

Despite the considerable improvement in the understanding of transformation toughening accomplished in the last three decades, it remains an important challenge to be able to control and tune the tetragonal ZrO2 phase transformability and associated toughness of polycrystalline tetragonal zirconia (Y-TZP) ceramics. The problem of controlling the toughness of Y-TZP is investigated in the present paper by comparing the mechanical behaviour of a number of ceramics derived from commercial co-precipitated and yttria-coated zirconia starting powders as well as a range of experimental powder mixtures, obtained by mixing monoclinic and 3 mol % yttria-stabilised powders. Based on the experimental results, a simple route to tailor the toughness of Y-TZP ceramics is reported. The effectiveness of this approach was investigated and the microstructural origin influencing transformation toughening is elucidated. The difference in toughness is explained in terms of the tetragonal grain size and the overall amount and distribution of yttria in the sintered ceramics. The overall yttria stabiliser content is of primary importance, the yttria distribution however was found to be an additional important microstructural variable influencing the transformation toughness of the investigated Y-TZP ceramics.