Annealing behaviour of ultrafine-grained aluminium

Ultrafine-grained (UFG) aluminium, processed under fast cooling rate conditions (12Ks(-1)) following hot rolling (water quenched) exhibits enhanced thermal stability due to an increase in concentration of solid solution atoms, relative to the furnace cooled material. The influence of fraction recrystallized on yield stress and uniform elongation is reported to exhibit a slight deviation from the linear behaviour that is anticipated on the basis of the rule-of-mixtures. This result was rationalized on the basis of differences in the spatial distributions of the UFG and coarse grains and/or dislocation recovery mechanisms.