Plasticization of Alumina Toughened Zirconia Ceramics with the Silica Addition

The purpose of this work is to study features of deformation at the room temperature by the method of uniaxial compression of alumina toughened zirconia ceramics (stabilized with calcium oxide) with different content of the silicon dioxide (CaO-ATZ+SiO2). It was found that SiO2 addition to the CaO-ATZ-ceramic ensured manifestation of the signs of plasticity at the room temperature, i.e., yield stage in the loading diagrams. The most pronounced plasticization was manifested at the silicon dioxide content of 4 mol. %. In this case, plastic deformation (calculated as the difference between deformations corresponding to the tensile strength and conditional yield strength) reached the 0.79 % value. In addition, introduction of the SiO2 additive (2 mol. % concentration) caused an increase in the ultimate compressive strength to the value of 2.66 GPa and ultimate strain to the value of 1.79 %. It was shown that exceeding the threshold value of the SiO2 concentration (by more than 4.5 mol. %) caused a sharp embrittlement of the CaO-ATZ+SiO2-ceramics. Discovered ceramics plasticity at the room temperature is explained by an increase in the tetragonal phase transformability of zirconium dioxide, which enhances the role of the transformation toughening mechanism. Plasticity margin of the composite ceramics based on the zirconium dioxide was achieved at the room temperature and provides a prospect for expanding the area of its practical applications