Influence of Iron and Silicon Impurities on the in-service Degradation of Alloys of the Al-Cu-Mg and Al-Zn-Mg-Cu Systems

We study micro- and nanostructures and the physicomechanical characteristics of D16chT, V95pchT1 and V95pchT2 aluminum alloys (analogs of 2524-T3, 7475-T6, and 7475-T761 foreign alloys, respectively) in the as-received state and after simulated degradation, which imitates the influence of long-term operation of these alloys. By using the obtained characteristics of strength σ YS and σ UTS , plasticity δ 5 , fatigue threshold Δ K th , cyclic fracture toughness Δ K fc and specific electric conductivity σ , it is shown that, if the contents of impurities decrease (silicon down to 0.08–0.18 wt.% and iron down to 0.2–0.23 wt.%), then we do observe the degradation of these alloys under the long-term action of temperature and force factors simulating the actual operating conditions.