Analysis of dynamic grain growth behavior during superplastic deformation using a grain boundary diffusion mechanism

The enhanced grain growth behavior during superplastic deformation is analy zed on the basis of grain boundary diffusion mechanism. On the grain bounda ry where both static and dynamic potential differences exist, matter diffus ing along the boundary is assumed to deposit on the grain surface locating opposite to the direction of grain boundary migration and to contribute to the dynamic grain growth. The amount of the diffusive matter is calculated for the deformation of a spherical grain and is converted to the increment in the mean boundary migration velocity. The obtained relationship between the strain rate and the dynamic grain growth rate is independent of the mec hanism of superplastic deformation. The dynamic grain growth behavior predi cted from the present model is consistent with the experimental results of ZrO2-dispersed Al2O3.