The limitations of the Chen & Argon and Martinez & Nix models for intergranular cavity growth

A Re-Appraisal of Cavity Growth Processes in Superplasticity

It is well known that cavities are nucleated and grow during the superplastic deformation of many materials. The various theories for cavity growth are examined with special emphasis on the role of growth by diffusion. It is demonstrated that the normal model for the diffusion growth of cavities is inadequate for superplastic materials when the grain boundary lengths are very small. By developing a new model for the growth of an isolated cavity to sizes exceeding the grain size, it is shown that the diffusion process may play a major role in cavity growth under a range of experimental conditions.