Superplastic alumina at temperatures below 1300 degrees C using charge-compensating dopants

To achieve low-temp. superplasticity in Al sub 2 O sub 3 , authors introduce charge-compensating dopants, Ti sup / 4+ / and Mn sup / 2+ / , which jointly have a high solubility and significantly enhance the diffusion and deformation processes during sintering and forming. ZrO sub 2 as a second-phase pinning agent is also incorporated to impart microstructural stability against static and dynamic grain growth. Superplastic Al sub 2 O sub 3 can be shape-formed under biaxial tension to 100% engineering strain at < 1300 degrees C. Deformation characteristics are described. The origin of enhanced kinetics is attributed to the formation and dissociation of dopant-defect complexes. 39 refs.