The objectives of this research is to study superplastic flow in fine grained metallic alloys. In particular, the effects of impurity atom segregation at the grain boundaries on creep and cavitation in Zn-22%Al and Pb-62%Sn will be investigated. Special attention will be given to delineating the mechanisms responsible for the observed creep stress threshold, and to determining the relationship between deformation and cavity growth in fine grain alloys. It is anticipated that the results of this research program will enhance the understanding of the role of impurity atoms in the deformation, formability, and fracture of superplastic alloys.
