Crystallographic orientation and electrochemical activity of AZ31 Mg alloy

Rolled AZ31 Mg alloy, which has great potential applications in the automobile industry, is detected to be highly crystallographic textured. Its rolling surface (RS), mainly consisting of (0001) crystallographic planes, is first time measured to be more electrochemically stable and corrosion resistant than its cross-section surface (CS) mainly composed of crystallographic planes (101̄0) and (112̄0) in 5 wt.% NaCl. The different corrosion performances of these crystallographic planes can be ascribed to their different anodic and cathodic reaction activities. A theoretical analysis confirms that the different electrochemical activities of RS and CS surfaces originate from the different surface energy levels of the (0001), (101̄0) and (112̄0) crystallographic planes.