Effects of coverage layer on the electrochemical corrosion behaviour of Mg-Al-Mn alloy subjected to massive laser shock peening treatment.

Abstract Effects of coverage layer on electrochemical corrosion behaviour and pitting morphologies of Mg-Al-Mn alloy subjected to massive laser shock peening (LSP) treatment were investigated by potentiodynamic polarisation test, electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) observations. Microstructures of Mg-Al-Mn alloy subjected to massive LSP treatment were also characterized. Results showed that LSP induced an obvious improvement in electrochemical corrosion resistance with increasing coverage layer. Even in a higher corrosive solution concentration, LSP could still prevent corrosion to some extent. The improvement in electrochemical corrosion resistance was due to the grain refinement and compressive residual stress induced by massive LSP treatment. Finally, the influence mechanism of the coverage layer on electrochemical corrosion behaviour of Mg-Al-Mn alloy was revealed. Graphical abstract Schematic illustration of the coverage layer on the electrochemical corrosion behaviour in NaCl solution. (a) The as-received, (b) the LSP-1, and (c) the LSP-4 specimen. Image 1 Highlights • LSP generated an obvious improvement in electrochemical corrosion resistance. • The increment of the coverage layer led to a stronger corrosion resistance. • Even in a more corrosive solution, LSP still prevent corrosion to a certain extent. • Influence mechanism of LSP coverage layer on corrosion resistance was revealed. [ABSTRACT FROM AUTHOR]