Predicting wear lifetime of MAO-treated aluminum foils through acousto-optic features and discharge-driven surface architectures

Micro-arc oxidation (MAO) with frequency-controlled pulses was applied to aluminum foils to regulate discharge behavior and improve wear performance. Acousto-optic monitoring revealed a frequency-dependent double-sided discharge caused by the thin-foil geometry. At 100 Hz, a dominant penetrating-type discharge produced a dual-layer oxide with a dense load-bearing base and a porous outer shell. This architecture promoted third-body stabilization and shifted the wear mode from adhesive–abrasive to mixed rolling–sliding, markedly extending wear lifetime. AE parameters (K_AE1 and K_AE2), extracted via UMAP clustering, were combined with film properties to develop a regression model that accurately predicts wear lifetime (R² = 0.99). The results connect discharge modes and microstructural evolution with interfacial mechanics, offering a mechanism-based and data-assisted approach to assessing durability of MAO-treated lightweight metals.