The effect of the secondary phases on the corrosion of AZ31B and WE43-T5 Mg alloys

The effect of secondary phases of AZ31B and WE43-T5 Mg alloys on corrosion behaviors was studied in 3.5 wt% NaCl solution. Electrochemical and microstructural characterizations revealed that compared to AZ31B, WE43-T5 suffered less hydrogen evolution without corrosion film breakdown. The corrosion film of both AZ31B and WE43-T5 was mainly Mg oxide/hydroxide. The TEM analysis revealed that Y and Nd oxide/hydroxide enrichment in the corrosion film/WE43-T5 interface resulted from the corrosion of the strengthening nanoparticles. Conversely, the Al-rich layer was not detected at the corrosion film/AZ31B interface, and the Al-Mn secondary phases caused severe galvanic corrosion.