On the Development of a Nanocrystalline Yttria Stabilised Zirconia Ceramic Capable of Superplastic Deformation at Relatively Low Temperatures
S.S. Bhattacharya, U. Betz and H. Hahn
IIT Madras, IN
Keywords: nanocrystalline ceramics, 5Y-PSZ, superplastic deformation, grain boundary sliding, activation energy
Superplastic deformation behaviour is now well established in fine-grained zirconia ceramics at fairly high temperatures (well above 0.5Tm, where Tm is the absolute melting point). In this study, an attempt was made to develop a nanocrystalline 5 mol.% yttria partially stabilised zirconia ceramic (5Y-PSZ) capable of exhibiting superplastic flow at relatively lower temperatures. A physical vapour processing route was used to synthesise the powders which was consolidated and subjected to a pressureless sintering route. Dense specimens with grain sizes in the nanometer range were subjected to tensile as well as compressive tests in the temperature range of 1283-1523K at different stress or strain rate levels in order to determine the superplastic deformation behaviour. The stress strain strain rate response of the material was analysed by a model for grain boundary sliding controlled superplastic flow. It was demonstrated that the strain rates predicted by the model are in close agreement with the experimentally observed ones.
Nanotech 2004 Conference Technical Program Abstract