Abstract
Superplastic elongation of fine-grained ceramics can be observed when some mechanical and microstructural requirements are satisfied at appropriate test conditions, temperature and strain rate. The phenomenon can be utilized in superplastic forming, solid-state bonding, sinter-forging, hot press, and hot-isostatic pressing. Recent advances in ceramic processing brought about not only superplastic structural ceramics (ZrO2, Al2O3, mullite, Si3N4. SIC and their composites), but also superplastic functional ceramics which have characteristic properties such as electronic, magnetic, optical, chemical or biological properties. Numerous works on superplasticity of ZrO2 ceramics since 1985 revealed some characteristics of superplasticity, microstructural feature, and possible mechanisms. Attempts to achieve high-strain rate superplasticity in ceramics were performed by modifying the nature of grain boundary.
