Cooperative grain-boundary sliding in polycrystalline ceramics

The microscopic processes and mechanisms are investigated for the superplastic deformation of 3mol% yttria-partially stabilized tetragonal zirconia polycrystals. Tensile tests are carried out by the use of test specimens with various dimensions in order to examine the “specimen size effect” on stress–strain curve. The formation and development of surface corrugation on tensile specimens induced during superplastic deformation are carefully studied as a function of tensile strain. New findings, i.e. the “specimen size effect” and the “surface corrugation” are discussed in terms of the concept of cooperative grain-boundary sliding as a candidate for superplastic deformation and flow of polycrystalline materials.