Strength and ductility of ultrafine grained aluminum and iron produced by ARB and annealing

Strength and ductility of ultrafine grained (UFG) aluminum and iron fabricated by ARB and annealing were clarified in the grain sizes ranging from 200 nm to 20 mum. Strength held Hall-Petch relationship, while uniform elongation of the UFG materials was limited below a few percents. The limited uniform elongation in the UFG materials could be explained in terms of plastic instability. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.