Abstract
A commercial 6061 aluminium alloy was processed by ECAP and subsequently aged to nucleate nanoscaled precipitates within the ultrafine grain structure. The mechanical behaviour was investigated thanks to tensile tests and the microstructure was characterized at the atomic scale using Atom Probe Tomography. These experimental data clearly reveal that extensive dynamic precipitation and grain boundary segregation occurred during ECAP. These features lead to a significant increase of the strength of the alloy. Further aging after ECAP processing gives rise to an additional increase of the strength linked to a larger precipitate density. A comparison of the morphology and the composition of precipitates nucleated during ECAP and during the standard T6 aging treatment shows that the precipitation kinetic is affected by the severe plastic deformation.

Key words
aluminium alloy, precipitation, grain boundary segregation, ECAP

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