Experimental investigation on damage evolution in pre-corroded aluminum alloy 7075-T7651 under fatigue loading

This paper experimentally investigates the fatigue damage evolution in pre-corroded aluminum alloy (AA) 7075-T7651 via digital image correlation (DIC) and scanning electron microscopy (SEM). Three stages of including accumulation, macro-crack initiation propagation are identified described combined analysis severity curves strain maps. The micro-cracking characteristics dominant fracture regions examined by fractography analysis. experimental results show that localized corrosion penetrated ‘L-S’ or ‘L-T’ surfaces promotes crack initiation, affecting nucleation location, cracking path, is accompanied with quasi-cleavage fracture. Damage failure progression differed temporally spatially between specimens for same loading conditions, due to stochastic diversity corrosion. Multiple corrosion-induced cracks were observed initiate evolve under different conditions: three typical modes, viz. single fracture, multi-crack competition parallel growth, depend on condition relative location initiation.