Fatigue-Corrosion Studies on the 2198-T851 (Al–Cu–Li) Alloy Containing Nb2O5 Sputtered Coating

This research investigates the influence of Nb2O5 coatings, produced by using reactive sputtering technique, on the surface of middle-tension specimens M(T), regarding fatigue crack growth curves (da/dN versus ΔK) under exposure to a 0.6 mol L–1 NaCl saline solution. Results demonstrated the corrosion process occurred in the vicinity of the crack tip, where stresses are elevated, and significant plastic deformation prevails, notably influenced by slip bands that induce microcracks, exposing fresh material layers to the corrosive surroundings. The Nb2O5 coatings enhanced the fatigue-corrosion resistance of the 2198-T851 aluminium alloy. This study marks an initial step towards more comprehensive investigations into the impact of Nb2O5 coating on improving the mechanical properties of the 2198-T851 aluminium alloy.