Electrochemical Evaluation of Compressed Selective Laser Melted AlSi7Mg and AlSi10Mg Alloys in Chloride Environment

Abstract

This study investigates the electrochemical behavior and corrosion mechanisms of selective laser melted (SLMed) AlSi7Mg and AlSi10Mg alloys in both their as‐received and mechanically compressed states in a 3.5 wt.% NaCl solution environment. Electrochemical techniques, including open‐circuit potential (OCP), cyclic potentiodynamic polarization (CPP), and electrochemical impedance spectroscopy (EIS), were employed alongside microstructural examinations using scanning electron microscopy (SEM) and X‐ray diffraction (XRD) for phase analysis. The results indicate that compressive stress enhances corrosion resistance by promoting microstructural densification, pore closure and the formation of a more stable and adherent passive film. AlSi10Mg alloy exhibited superior corrosion performance due to its higher silicon content, which facilitates a refined and continuous eutectic Si network, reducing microgalvanic activity and improving passivity. AlSi7Mg demonstrated relatively lower corrosion resistance, attributed to its less stable passive film and susceptibility to localized attack. The findings demonstrate that compressive stress and increased silicon content synergistically enhance resistance to pitting corrosion by stabilizing the passive film and limiting localized breakdown, thereby improving the suitability of SLMed Al–Si–Mg alloys for chloride‐rich environments.