Production of ultrafine-grained metallic materials using an intense plastic straining technique

Superplasticity requires a very fine grain size, typically in the range of similar to 1-10 mu m. Experiments have established that even finer grain sizes, in the submicrometer and nanometer range, may be achieved in metals by using an intense plastic straining technique such as equal-channel angular (ECA) pressing. This paper examines the microstructural characteristics and the stability of two different aluminum-based alloys subjected to ECA pressing: an Al-3% Mg solid solution alloy and a commercial Al-5.5% Mg-2.2% Li-0.12% Zr alloy containing a fine dispersion of delta' Al3Li and beta' Al3Zr precipitates.