Effect of Cross Rolling on the Corrosion Resistance of AZ31 Magnesium Alloy

The effect of different rolling methods on the microstructure and corrosion behavior of AZ31 magnesium alloy in a 3.5% NaCl solution was studied via potentiodynamic polarization scanning, constant current discharge and electrochemical impedance spectroscopy. Results show that the corrosion current densities of cross rolling and unidirectional rolling are 8.60 10-3 and 4.68 10-2 A/cm2, respectively. Their difference is 5.4fold, the charge transfer resistance of cross rolling is large, the corrosion of one-way rolling is more serious than that of cross rolling, the discharge performance of cross rolling is more stable, and the anode polarization is small. After cross rolling, the grain size of the plate is relatively uniform and the corrosion products are non-adherent and less, so it is easy to fall off from its surface, which increases the effective contact between the electrolyte and the alloy surface and has more stable discharge performance.