Dynamic and Static Grain Growth During the Superplastic Deformation of 3Y-TZP

Static grain growth in Y-TZP is believed to be controlled by a solute drag mechanism in TZP, resulting in an activation energy (524 kJ/mol) between that for grain boundary and lattice diffusion of cation dopants in TZP. The dynamic grain growth rate of 3Y-TZP when normalized by grain size is linearly related to the strain rate with a proportionality constant of 0.13. When dynamic grain growth data for a wide range of metals and ceramics are analyzed, all of the data exhibit the same linear dependence on strain rate, with a proportionality constant of approx0.1. Temperature-related scatter may be due to the inter-dependence of static and dynamic grain growth kinetics. Dynamic grain growth does not seem to be dependent on the chemistry of the material being studied but, instead, appears to be intimately related to the deformation mechanism of superplasticity.