Influence of the thermal route on the peak-aged microstructures in an Al–Mg–Si aluminum alloy

The influence of the thermal route on the peak-aged microstructures in an Al–Mg–Si aluminum alloy was investigated by atom probe tomography and transmission electron microscopy. Direct artificial aging induced a monomodal size distribution of β″-precipitates, while for artificial aging after natural pre-aging a bimodal size distribution was found. This difference can be explained by the impact of lattice defects on the β″-nucleation. β″ is supposed to contain Al and exhibits a high Mg/Si ratio in the studied alloy.