Effect of fabrication process-related cooling rates on the corrosion behavior of Al-Si-Mg Alloys

Kurzfassung

Aluminum components for automotive and aerospace applications exhibit a high weight reduction potential and good recyclability, meeting the requirements of concepts for the circular economy. Consequently, further development of structural and functional aluminum parts is an important part of lightweight construction concepts for more sustainability. Depending on the geometries of the parts and the production route, microstructures of metallic materials vary significantly, resulting from varying cooling rates during solidification by casting, and even additive manufacturing processes. So far, effects on microstructure and corrosion behavior of Al-Si alloys have been investigated in less systematic studies, regarding the influence of cooling rate. Therefore, a systematic study with an Al7Si0.6Mg-Aluminum-Alloy (F357) is carried out, linking variations in corrosion mechanisms to the size and features of cast microstructures for as-built and heat-treated samples, as well as their nano-structural features. The cell size of cast microstructures with varying cooling rates are simulated with levitation techniques. Subsequently, potentiodynamic and static corrosion experiments are executed in sodium chloride containing solutions with various concentrations. The corrosion behavior varies with the cooling rate-dependent microstructure, disclosing the challenges of corrosion on the alloys production process.