Influence of Mn on the precipitates in 6082 aluminum alloy

The study systematically examined how Mn impacts the precipitates and mechanical properties of 6082 aluminum alloy during the peak state of artificial aging following various natural aging durations, elucidating the underlying mechanisms. It is found that α-Al(Mn,Fe)Si precipitated during homogenization is less in amount in the alloy with lower Mn content, resulting in the less consumption of Si and a lower real Mg/Si ratio to create a relatively Si-rich environment in matrix. The Si-rich environment promotes the nucleation of the precipitates, so that the low Mn alloy precipitates more and finer precipitates in the artificial aging process, and has higher strength than the high Mn alloy. Additionally, it is also found that with the increase of natural aging time, the precipitates of 6082 aluminum alloy are significantly coarsening, and the alloy with lower Mn content can better resist the coarsening process of the precipitates, so that the strength of the alloy decreases more slowly than that of higher Mn alloys, and the negative effects of natural aging are lighter.