Microstructure evolution of a modified AA5083 aluminum alloy during a multistage homogenization treatment

The microstructure evolution of the industrially cast AA5083 modified aluminum alloy during the multistage homogenization treatment was investigated by means of optical, SEM and TEM imaging and microanalysis techniques. The effect of microsegregations on the precipitates structure was evaluated. Eutectic constituent Al6(Fe,Mn) and Mg2Si particles form in interdendritic regions, while ν-Al11(Mn,Cr)4 dispersoids were observed in the dendrite cores. Homogenization treatments lead to a partial dissolution of the precipitates present in the as-cast state and formation of the new phases: rod-shaped Al6(Mn,Fe) and Al18Mg3(Mn,Cr)2 dispersoids in the dendrite cores.