Corrosion behavior of AA5182 Al–Mg casts in HNO3: A comparative study of thin-strip and direct-chill casting

This study investigates the corrosion behavior of AA5182 Al–Mg alloy produced by thin-strip (TS) and direct-chill (DC) casting. Through immersion tests, polarization measurements, and electrochemical impedance spectroscopy (EIS), the impact of as-cast microstructure on corrosion resistance in HNO3 solution was examined. The results show that TS samples with reduced formation of intergranular Mg-rich eutectics, particularly β-Al3Mg2, exhibit a lower degree of sensitization (DOS), attributed to Mg supersaturation in the matrix due to rapid solidification, and demonstrate superior corrosion resistance.