Corrosion Resistance of AZ31 Magnesium Alloy Processed by Femtosecond Laser Shock Peening

Abstract

The present study investigates the impact of femtosecond laser shock peening (FLSP) on the corrosion resistance of an AZ31 magnesium alloy. The alloy was subjected to irradiation with varying pulse energies in an air environment, and subsequent modifications in surface properties were characterized. Surface wettability, assessed by contact angle measurements, indicated enhanced hydrophobicity following FLSP, especially at higher pulse energies. Corrosion behavior after immersion with various durations was assessed in a 3.5% NaCl solution using electrochemical polarization curves and electrochemical impedance spectroscopy, applying a three-electrode system. The results revealed that FLSP significantly augmented corrosion resistance; the most notable effects were observed at higher pulse energies. SEM/EDS analysis post-corrosion revealed a transition from localized to more uniform corrosion, accompanied by reduced pit size and density. XRD and XPS confirmed the formation of a protective Mg(OH)2 layer, which exhibited greater stability and uniformity at higher laser energies. The study concluded that FLSP represented an effective approach for enhancing the corrosion resistance of the AZ31 magnesium alloy, with potential applications in improving the longevity of magnesium alloy components in industrial settings.