Mechanism of Pitting Corrosion Anisotropy in Cold-Rolled 7075 Aluminum Alloy Governed by Residual Stress

This study investigates the synergistic influence of residual stress and microstructural evolution on corrosion anisotropy of cold-rolled 7075 aluminum alloy across four oriented surfaces (rolling direction (RD), normal direction (ND), transverse direction (TD), and a surface oriented 45° to the rolling direction (RD45°), under rolling reductions of 5-40%. Pitting corrosion is the dominant degradation mode, and its severity increases with residual stress. Corrosion anisotropy is further governed by crystallographic texture and dislocation architecture. Isolated residual stress and dislocation density increase monotonically with rolling reduction and correlate linearly with corrosion rate, yet neither alone predicts corrosion performance. The ND surface, dominated by (111) texture, exhibits the best resistance due to a compact passive film, whereas the RD45° surface shows the poorest performance. Rolling‑induced dislocation bands along RD promote directional corrosion propagation, while the ND surface displays isotropic behavior. Thus, the corrosion anisotropy arises from the synergistic interplay of residual stress, dislocation networks, texture, and precipitate evolution, providing a quantitative framework for optimizing rolling parameters to balance mechanical performance and corrosion resistance. • Unveils a non-monotonic effect of cold-rolling deformation on corrosion resistance of 7075 aluminum alloy. • Establishes residual stress and crystallographic texture as the governing factors for pronounced corrosion anisotropy. • Identifies pitting as the dominant corrosion mode. • The (111)-orientated ND surface forms a stable Al₂O₃ passive film with superior resistance.