A novel deformation mechanism for superplastic deformation

Uniaxial compressive creep tests with strain value up to -0.1 for a beta-spodumene glass ceramic are conducted at 1060 degrees C, From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes pla,ce via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation.