Corrosion behaviour of friction stir welded AZ31B Mg in 3.5%NaCl solution

Abstract

The corrosion behaviour of friction stir welded AZ31B-H24 and -T4 Mg alloys in 3.5%NaCl solution was examined based on potentiodynamic test and constant immersion test results. For friction stir welded AZ31B-H24 specimens, the corrosion potential was higher compared with as received (i.e. parent) specimens, while the trend was reversed for AZ31B-T4 specimens. The present corrosion test results appear to be closely related to the grain size of the friction stir welded specimens. The effects of prior T4 heat treatment, and subsequent microstructural evolution, with friction stir welding on the corrosion behaviour is discussed based on potentiodynamic tests, constant immersion tests and micrographic observation.