Room-temperature plasticity of alumina-toughened zirconia with silica addition

Alumina-toughened zirconia (ATZ) is widely used in various fields due to its unique complex of mechanical properties. However, brittle fracture at room temperature remains a significant drawback of the material. Special additives are used to induce plasticity due to the martensitic transformation of the tetragonal t-ZrO ₂ phase into monoclinic m-ZrO ₂ . The room-temperature uniaxial compression deformation of bulk ATZ ceramics with variable silica content (0 mol% ≤ C _SiO2 ≤ 6 mol%) was studied in this paper. X-ray diffraction was used to monitor phase composition of the material at different deformation stages. It was shown that the SiO ₂ addition to the ATZ ceramics causes the stress reduction required for the t-ZrO ₂ → m-ZrO ₂ phase transformations. This provides strengthening the role of a transformation toughening mechanism (increase in the compressive strength from 2.12 GPa to 2.55 GPa) and appearance of transformation plasticity (residual deformation ε _P = 0.5%). The results obtained and the conclusions drawn made it possible to advance the understanding of the physical nature of ATZ + SiO ₂ ceramics plastic deformation at room temperature.