Corrosion behavior of a Mg alloy AE42 subjected to friction stir processing

Abstract

The goal of the current investigation was to analyze the influence of friction stir processing (FSP) on the corrosion behavior of a magnesium alloy, AE42. The alloy was friction stir processed under a wide range of FSP conditions. The corrosion behavior of the as-cast as well as friction stir processed AE42 alloy was investigated using immersion corrosion and electrochemical corrosion tests in 3.5% sodium chloride (NaCl) solution. Electrochemical corrosion testing comprised potentiodynamic polarization, polarization resistance and corrosion potential trend (Rp/E c), and electrochemical impedance spectroscopy (EIS). The electrochemical as well as immersion corrosion tests revealed reduced a corrosion rate for the friction stir processed AE42 alloy. The reduced corrosion rate of the FSP AE42 alloy may be attributed to the microstructural refinement resulting in grain size refinement and presence of fine in situ precipitates.