On the emergence of new surface grains during superplastic deformation

Abstract

Superplasticity, the ability of some polycrystalline materials to exhibit large elongations to failure offers an attractive and cost effective means for forming some components with complex shapes, and it is being used currently in several aerospace and other applications [1-3]. Although the phenomenon has been studied extensively since the 1960's [1,2,4 -7], the fundamental rate controlling deformation mechanism has not yet been unambiguously identified. One of the key microstructural observations following superplastic deformation is the retention of an equiaxed grain size following large elongations.