Aging behaviour and mechanical properties of a solution treated and ECAP processed 6082 alloy

A study was carried out on the aging behaviour of a solution treated 6082 aluminium alloy deformed by equal channel angular pressing up to six passes. Aging of the so obtained ultrafine alloy was studied by DSC and TEM analyses as well as by isothermal treatments at 130, 160 and 180C. The results showed that the formation of metastable beta double prime and beta prime precipitates were markedly anticipated and that the stable phase was partially suppressed in the alloy processed to 4 and 6 passes, presumably due to anticipated precipitation of Si-rich particles. TEM analyses revealed that a transition in strengthening-precipitate structure occurred in the severely deformed alloy leading to a predominance of globular precipitates over the rod like phases typically found in the undeformed and aged samples. Tensile tests carried out on severely deformed and aged samples allowed to quantify the maximum strength achievable by the 6082 alloy after concurrent grain refinement and peak-hardness aging at 130C.