Role of oxygen phonons in the martensitic phase transformation of yttria stabilized tetragonal zirconia polycrystals

摘要

The tetragonal (t) to monoclinic (m) martensitic phase transformation in stabilized tetragonal zirconia polycrystals (TZP), which is responsible for the well-known transformation toughening, is of interest [1]. Clapp proposed that the martensitic phase transfor-mation is triggered by a strain induced elastic instability in particular regions, called localized soft mode (LSM) centres, and that the lattice vibrations or phonons in these anomalous regions play an important role in the nucleation process [2]. Based on transmission electron microscopy (TEM) observa-tions, Heuer and Riihle argued that the nucleation in yttria stabilized TZP (Y-TZP) occurs by the Clapp-type LSM mechanism at stress concentrations such as grain boundaries and grain corners [3].