Fatigue Crack Initiation and Growth Behavior of 7475 Aluminium Alloy in Air and Aggressive Environment

摘要

Present investigation is devoted to study the effects of aqueous solution of 3.5% NaCl on high-cycle stress life and fatigue crack growth behavior of 7475-T7351 alloy. At low alternating stress the environment test exhibited corrosion pit dominated crack initiation and at high stress level crack initiation occurred through anodic dissolution. Corrosive environment resulted reduction in fatigue life, crack growth rate enhancement and drop in stage-I to stage-II transition. The behavior is explained with the help of fractographic observations.