Some Observations on the Stress Corrosion Characteristics of High Strength Aluminum Alloys in the Marine Environment

The stress corrosion susceptibility of aluminum alloys 7002-T6, X7106-T63, and 7039-T64 was investigated as a function of longitudinal, long transverse and short transverse plate orientations. All three alloys were found to be subject to stress corrosion cracking in flowing sea water, and variations in cracking susceptibility were related to microstructural characteristics. Specimens having short transverse orientations were found to be the most susceptible. The use of precracked cantilever specimens to assess stress corrosion behavior in these alloys is discussed in light of microstructural directionality characteristics. Fracture toughness data on all three alloys are also presented.