Impact of abrasive jet machining on the fatigue behaviour of corrosion-exposed UNS A97075 alloy

Abstract

Surface conditions are a decisive factor in the fatigue performance of aeronautical components, particularly for alloys highly susceptible to corrosion, such as UNS A97075. This study investigates the combined influence of machining parameters, corrosion, and Abrasive Jet Machining on the geometric accuracy, surface roughness, and fatigue behaviour of rotary-bending specimens. Two cutting conditions were applied, followed by controlled sequences of corrosion and Abrasive Jet Machining to evaluate their synergistic effects. The results show that machining under more severe conditions increased roughness and form deviations owing to higher cutting forces, vibration and thermal loading. However, the sequence of post-machining operations exerted a far greater impact on surface conditions and fatigue life than machining parameters alone. When Abrasive Jet Machining was applied after corrosion, roundness and cylindricity were partially restored, roughness was stabilised, and fatigue life was significantly extended. Conversely, Abrasive Jet Machining performed before corrosion amplified pitting, produced severe geometric distortions, and reduced fatigue life by more than 50%. These findings demonstrate the dual role of Abrasive Jet Machining as either a restorative or detrimental treatment depending on process order, providing clear guidance for the optimisation of manufacturing and maintenance strategies in aerospace aluminium alloys exposed to corrosive environments.