Effect of anodic oxidation on fatigue performance of 7075-T6 alloy for pre-corroded and non-corroded
specimens has been investigated by conducting a series of rotary bending fatigue tests at 95 Hz. The anodized
specimens with different coating thickness (6, 12 and 23 μm) were exposed to 3.5 wt.% NaCl solution for 6,
48, 96 and 240 h. The results indicate that oxidation has a tendency to decrease the fatigue performance.
Fatigue strength was reduced with increasing coating thickness; approximately 40% reduction for a 23 μm
thick coating was obtained. It was observed that oxidation mitigated pitting corrosion. Superior corrosion
resistance was obtained for the thickest coating layer. Fatigue tests with pre-corroded specimens showed
that fatigue life of coated specimens was significantly affected by pre-corrosion, except for the specimen with
the thickest coating layer. When the pre-corroded bare and coated specimens were compared, the coating
improved the fatigue performance in high cycle fatigue (N105
) only and it degraded the fatigue performance
in low cycle regime.