Corrosion and Discharge Behavior of As-Rolled AZ91 Magnesium Alloy after Electro-Pulsing Treatment

Abstract

In this article, a systematic investigation into the corrosion and discharge behaviors of as-rolled a represents aluminum, Z represents zinc, 9 and 1 represent their respective contents of 9% and 1% in the alloy (AZ91) magnesium alloy after electro pulsing treatment (EPT), considering rolling deformations of 0% (as-cast AZ91 magnesium alloy), 20%, 30%, and 40%, is presented. In this investigation, immersion weight loss tests, electrochemical tests, and other experimental methods are employed. In the results, it is revealed that the content of the β-Mg₁₇Al₁₂ phase gradually decreases with increasing rolling deformation after EPT. Notably, the highest content of β-Mg₁₇Al₁₂ phase and the most outstanding corrosion resistance are achieved with as-cast AZ91 magnesium alloy. Furthermore, at low current densities (5 and 10 mA cm⁻²), the 30% rolling deformation exhibits superior discharge activity, while the discharge activity of the 40% rolling deformation is most excellent at high current densities (40 and 50 mA cm⁻²). The microstructure observations support these findings, highlighting the close relationship between the corrosion resistance and discharge activity of as-rolled AZ91 magnesium alloy after EPT, and the content of the β-Mg₁₇Al₁₂ phase and the area of high-energy grain boundaries.