Significance of Internal Stresses for the Martensitic Transformation in Yttria‐Stabilized Tetragonal Zirconia Polycrystals During Degradation

Authors:
Publisher website
Google Scholar
Abstract
Various aspects of the tetragonal (t) to monoclinic (m) transformation during degradation have been studied experimentally and theoretically in yttria‐stabilized tetragonal zirconia polycrystals (Y‐TZP), i.e., polycrystalline t‐ZrO2 containing Y2O3 in solution. Transmission electron microscopy (TEM) revealed that protruding grains at the surface of Y‐TZP specimens do not transform under corrosive conditions (250°C, humid atmosphere) even after an annealing time of 168 h. Eigenstresses due to anistropic thermal expansion In and around protruding and bulk grains have been calculated for Y‐TZP containing 2 and 3 mol% Y2O3. The prominent role of these stresses on subsequent transformation nucleation during degradation is shown to agree qualitatively with an established free energy concept. The lack of complete transformation of m‐ZrO2 is attributed to characteristics of the nucleation‐ and growth‐controlled transformation process.

This publication has 15 references indexed in Scilit: