Phase transformations induced by mechanical stresses in powders of oxide solid solutions

The influence of cold isostatic pressing to 2.0 GPa on the phase transformations in powders of ZrO₂-Y₂O₃ solid solutions and γ-Al₂O₃ is investigated. The cold isostatic pressing of ZrO₂-Y₂O₃ is shown to lead to conversion of the tetragonal modification into a monoclinic phase. The extent of conversion decreases as the Y₂O₃ content and the particle size increase. In the case of γ-Al₂O₃ powders, cold isostatic pressing at 1.5 GPa leads to lowering of the temperature at which the aphase appears by 100 K in comparison to a γ-Al₂O₃ powder subjected to cold isostatic pressing at 0.1 GPa. A quantitative model, which accounts for the experimental results discovered, is proposed. Zh. Tekh. Fiz. 69, 27–31 (February 1999)