Abstract
Recent research into superplasticity has developed substantially, to the extent that there are now important directions for future investigations, one of which is high strain rate superplasticity (i.e., superplastic behaviour at strain rates over 10-2 s-1) in metallic materials. Superplasticity at extremely high strain rates over 100 s-1 has been demonstrated and labelled as positive exponent superplasticity. Recent work on processing to produce ultrafine grained materials, and on deformation mechanisms and applications of high strain rate superplasticity, is reviewed and considered along with previously reported data.