Abstract:

Lightweighting is a key contributor to improved fuel economy of internal combustion vehicles, and range of battery electric vehicles, required to meet regulated greenhouse gas emissions reduction and circular economy targets. Al alloys with suitable mechanical properties and castability are widely used for thin-wall structural components with complex shapes using die casting processes. Their ease of recyclability makes them attractive for secondary alloy component production. Initial research and development focus has been placed on mechanical properties of secondary Al alloys, which can be made to be comparable to those of primary alloys. Focus is now shifting to corrosion performance. In this research, AlSi10MnMg-T7 materials produced using with a high vacuum (HV) HPDC process with different end-of-life (EOL) content (0%, 40%, 75%, and 90%) are subjected to electrochemical polarization and microstructure characterization to explore the effect of EOL content on corrosion susceptibility. Microstructure characteristics such as grain size, Si eutectic and intermetallic particles (IMPs) distribution differed from the primary alloy, which adversely affected corrosion susceptibility of secondary alloys. Various polarization measurements suggested that secondary alloys are more susceptible to localized corrosion. Corrosion visualization through agar gel experiment confirmed that secondary alloys are more susceptible to localized corrosion initiation.

Keywords: Al alloys, die casting, recycle, microstructure, corrosion

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Alejandro Gonzalez Villarreal