Wrought aluminum alloy 7X75 is mainly used in highly stressed structural components in aircraft applications due to its high specific strength and good fracture toughness. Zinc and Magnesium are responsible for precipitation hardening, whereas the combination of Copper and Chromium leads to an additional increase in strength and improves resistance to stress corrosion. The investigations were conducted on three different types of plate material with thicknesses of 75 and 80 mm in overaged condition (T7351), which exhibit different fracture toughnesses. The main task of this work was to analyse the factors influencing fracture toughness and to enable future improvements. The focus of interest was the grain structure and characteristics of the prevailing precipitates as well as chemical composition, electrical conductivity, hardness, and toughness. Special attention was paid on the variation of properties over the thickness of the plate material.