Microstructure-Tuned Hydrogen Embrittlement in 7050 Aluminum Alloy: Combined Impedance Analysis and Advanced Characterization

This study explores the influence of aging on hydrogen embrittlement (HE) susceptibility and corrosion resistance of AA7050 via microstructural characterization, slow strain rate tensile testing, thermal desorption spectroscopy, and electrochemical measurements. Prolonging aging (2–72 h) transforms grain boundary η -phase (MgZn 2 ) from continuous to discontinuous distribution, widens precipitate-free zones), and increases the HE susceptibility index from 13.69% to 55.80%. Short-aged samples (2 h) exhibit dimple fractures dominated by hydrogen-enhanced decohesion, while long-aged samples (24–72 h) show mixed intergranular/quasi-cleavage fractures via synergistic HEDE and hydrogen-enhanced localized plasticity. Hydrogen accumulates at Al/Al₇Cu 2 Fe interfaces, weakening cohesion. H-charged samples display reduced oxide film thickness and degraded corrosion resistance, confirming a corrosion-HE feedback mechanism. This work provides insights for optimizing aging processes to enhance AA7050 performance.