Effect of Zn Content on Corrosion of As-Cast Al-Fe-Zn-Mg Dilute Eutectic Alloys for Automotive Applications

The objective of this work was to determine the effect of the Zn content on the corrosion susceptibility of dilute Al-Fe (Zn,Mg) alloy samples produced by a vacuum-assisted high-pressure die casting process. Corrosion susceptibility was assessed using an ASTM G85-A2 cyclic corrosion test with post-exposure mass loss and cross-sectional examination by scanning electron microscopy. Increasing Zn content reduced corrosion susceptibility by reducing the amount of primary Al attacked after the initial attack of the solute (Zn) enriched zone that forms adjacent to the grain boundaries.