Due to their favourably properties such as high strength and good corrosion resistance, 6xxx aluminium alloys are well established in the automotive industry. In Europe the alloy EN-AW 6016, an almost Cu-free version, dominates the market. The sheets are formed in the naturally aged state and achieve their final strength during a subsequent heat treatment. Due to economic reasons the bake-in process, which is usually executed at 185°C for 20 min, shall be used for artificial aging. Therefore sheets with accelerated aging kinetics are required. It is known that an additional pre-aging process after the solution heat treatment accelerates the aging kinetics. In this thesis microstructural differences in several aging conditions and their influence on the mechanical and corrosion properties are examined. Therefore high resolution methods like atom probe tomography (APT), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HR-TEM) were used. The near atomic resolution of the atom probe was used to study the formation of clusters in different aging conditions. These results allowed to draw conclusions about differences in aging kinetics. Grain boundaries and their influence on the intergranular corrosion were analysed by means of transmission electron microscopy. Furthermore, HR-TEM measurements were carried out to confirm the obtained APT data.