Laser assisted modification of surface microstructure for localised corrosion resistance of magnesium alloys

Poor corrosion resistance is a major obstacle in widespread application of Mg alloys. In the present study, cast Mg alloys, AZ61 and AZ91 were subjected to laser treatments with a view to modifying surface/subsurface microstructure and improving the microstructure assisted localised corrosion resistance of the alloys. Comparison of the laser treated surface microstructure with the bulk microstructure, as observed by reflected light microscopy demonstrates significant alterations. Immersion and anodic polarisation tests of the laser treated and untreated specimens in sodium chloride solution have suggested a variation in corrosion behaviour with improvements in corrosion resistance.