Effect of Preexisting Corrosion on Fatigue Cracking of Aluminum Alloys 2024-T3 and 7075-T6

摘要

A significant number of commercial and military aircraft have reached or exceeded their original design life, and fleet surveys have shown that the major problem of corrosion is increasing with the fleet's age. Corrosion can affect an airframe's structural integrity in three different ways. First, corrosion has a direct effect on aircraft structures by causing metal loss, which affects the residual strength, and thereby reduces the structural integrity of aircraft components. Secondly, corrosion can act in conjunction with mechanical stresses, resulting in cracking phenomena such as stress-corrosion cracking (SCC) and corrosion-fatigue cracking (CFC). Thirdly, with the aging of the fleet, the interaction between preexisting corrosion and fatigue cracking may affect safety and durability of structural aircraft components.