Plastically deforming amorphous ZrO2-Al2O3 Original Research Article

We report for the first time non-viscous, plastic deformation in an amorphous oxide: ZrO2-Al2O3. Dense samples of amorphous ZrO2-Al2O3 made by hot pressing spray-pyrolysed powder were deformed in uniaxial compression at 600–700°C at strain rates from 6×10−5 s−1 to 10−3 s−1. A transition from elastic to plastic deformation occurred at a critical stress ~360 MPa. The onset of plastic deformation was associated with a drop in the stress by 20–25%. Little influence of strain and strain rate on the flow stress was observed. The non-viscous, plastic deformation is related to the open structure of the amorphous phase as indicated by its low true density.