Corrosion of hot extrusion AZ91 magnesium alloy: I-relation between the microstructure and corrosion behavior

The effect of hot extrusion on the corrosion behavior of AZ91 magnesiun alloy was investigated by weight loss, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. The results showed that the extruded alloy had lower corrosion resistance compared to cast alloy. This observation has been explained from point of view of microstructure changes, wherein the increased density of dislocation, twins and grain boundary increased the anodic dissolution of AZ91 alloy and rearrangement of beta phase accelerated the rate of both the anodic and cathodic process. (C) 2011 Elsevier Ltd. All rights reserved.