What is Effect of corrosion on fatigue life?

Yes it will bring down the fatigue life and the material will not endure at any point. Degrading nature of fatigue loading on the materials is compounded by the corrosion interaction. Synergistic damage - The damage will be more than the addition of damages due to corrosion and fatigue loading. The formation of intrusion and extrusion due to fatigue loading leads to the notches. The corrosion media will enter the notches and forms oxide with the base metal and it will be passive to further corrosion. But the fatigue loading will disturb the passive layer and facilitate the media to corrode the fresh material. Hence it will drastically decrease the fatigue life of the material.