Transformation-induced plastic deformation in Ce-TZP/alumina nanocomposite generated during fatigue tests at room temperature

An approximate permanent strain of 0.3% was generated in Ce-TZP/alumina nanocomposite during static fatigue tests carried out at room temperature under ≈800 MPa for up to 106 s. For the deformed specimens, changes in the crystalline phase, ferroelastic domain orientation, and residual stresses were investigated. No evidence to support crystalline orientation due to ferroelasticity was observed. The monoclinic content of the deformed surface was determined to be 27 and 17 vol% by using small-area XRD and Raman spectroscopy, respectively. The estimated and experimental strains corresponding to the transformed monoclinic content were roughly in good agreement. A fairly high transformation zone and compressive residual stresses were observed up to 100 μm depth from the surface. Generated permanent strain and residual stresses disappeared completely upon annealing at 1100 °C. The obtained results revealed plastic deformation to be principally attributable to volume dilatation caused by t–m transformation and that it developed with residual strains.