Improving the tensile ductility and uniform elongation of high-strength ultrafine-grained Al alloys by lowering the grain boundary misorientation angle

A high-strength, ultrafine-grained Al alloy with a lamellar structure was fabricated via cryomilling and consolidation (hot isostatic pressing), followed by a two-stage thermomechanical processing approach (e.g. high temperature rotary swaging and room temperature high strain rate extrusion). Each lamellar band consisted of multiple ultrafine grains connected by low misorientation angle grain boundaries. This structure allows the dislocations to glide through low misorientation angle grain boundaries and to accumulate within the band, providing a high uniform elongation while retaining high strength. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.