Effect of yttrium on corrosion behavior of extruded AZ61 Mg alloy

The corrosion behavior of extruded AZ61 magnesium alloy with different addition of yttrium ranging from 0 to 0.9 wt. % was investigated. The electrochemical techniques in naturally-aerated 0.01 M NaCl solution and the surface analyses are utilized. The electrochemical results show that the pitting potential, time to pitting initiation, film and charge transfer resistances of the AZ61 specimens increased with the increase of yttrium content. Surface analyses indicate that yttrium promotes the formation of passive films and the refinement of the precipitates and matrix grains.