Galvanic Corrosion-Induced Fatigue Crack Initiation and Propagation Behavior in AA7050-T7451

Electrochemical experiments were used to create morphologies representative of galvanically-induced corrosion between aluminum alloy (AA) 7050-T7451 (UNS A97050) and Type 316 steel (UNS S31600) in a fastener configuration. The effects of these corrosion damage morphologies on the fatigue behavior were investigated. Results showed that severe macroscale metrics considered for discrete pits and general corrosion with surface recession do not correlate with the location of fatigue crack initiation. However, for intergranular corrosion, the plane that had higher number of fissure and higher total fissure depth tended to correlate to the location of fatigue crack formation.