Investigation Corrosion Fatigue Behaviours of 7075-T6 Aluminum Alloy in Sea Waterr

Aluminum alloys due to high strength to weight ratio and good corrosion resistance as compared with other metals, have many applications in sea industries. Most of sea structures are under cycle loadings and these leads to fatigue process. Also, because the structures are in a corrosive environment, sea water, so corrosion process effects on them too and leads to destroy efficiency of the this structures. So investigation of effect of fatigue and corrosion together are an important factor in selecting of an aluminum alloys. In this paper corrosion fatigue behavior of 7075-T6 aluminum alloy was investigated and with obtained results from fatigue test in air was compared. results of the paper shows that a corrosive environment had detrimental effects on the specimen was under cyclic loadings and led to decrease corrosion fatigue life of this alloy in a corrosive environment such as sea water. Corrosive environment lead to form pits on specimens surface and fatigue crack can initiate from the pits and propagate. Fatigue strength of the alloy 33% decreased as compared with specimen in air.