Abstract
Experiments were conducted to evaluate the evolution of hardness and microstructure in a commercial aluminum 6061 alloy processed by high-pressure torsion (HPT). The results show that processing by HPT leads to significant grain refinement with an average grain size of 450 nm at the edge of a disk subjected to torsional straining through 5 turns. Hardness measurements show an increase from 80 Hv in the solid solution condition to 160 Hv after HPT where these values correlate well with the equivalent strain applied to the disk. Quantitative measurements show the grain size decreases and the fraction of high-angle grain boundaries increases with increasing strain. (C) 2010 Elsevier B.V. All rights reserved.