Corrosion of Secondary Hpdc A365 (AlSi10MnMg(Fe)) Alloys for Automotive Applications

Al alloys with suitable mechanical properties and castability are widely used for thin-wall structural HPDC components with complex shapes. Al alloy A365 (9-11.5% Si, 0.4-0.8%Mn, 0.1-0.6% Mg, 0.25% Fe max.) is typically produced using primary Al (raw material) to control/minimize the impurity Fe content. Secondary A365, made using recycled end-of-life material, with equivalent mechanical properties as the primary alloy, provides an opportunity to reduce life cycle greenhouse gas (GHG) emissions from light-duty vehicles through improved end-of-life material recovery. The primary alloy is susceptible to micro-galvanic corrosion, where the eutectic a-Al phase serves as the anode and the eutectic Si phase, and incorporated secondary intermetallic phases serves as the cathode. The purpose of this work is to determine the extent to which utilization of end-of-life materials alters the microstructure and, in turn, corrosion (anode and cathode kinetics) of secondary A365, as revealed by electrochemical measurements.