LAUSR

Abstract In this study, the effect of aging prior to extrusion (APE) on the microstructural evolution and corrosion resistance of Mg–8Sn–2Zn–0.2Mn alloy was investigated. The APE alloy processed refined and uniformly distributed secondary phases, while there were some large and banded phases existed in the Non-APE alloy. And the microstructure of the APE alloy was much more homogeneous than that of the Non-APE alloy. The large and banded Mg2Sn particles were more likely to be the corrosion initiation, and the amount of corrosion pits of the Non-APE alloy was much more than that of the APE alloy. The corrosion rates, measured by weight loss in a 3.5 wt% NaCl solution, were 4.58 mm/y and 6.33 mm/y for APE and Non-APE alloys, respectively. The decrease in the overall corrosion rate after APE treatment was as a result of the corrosion morphology changed from localized and deep galvanic corrosion to uniform and shallow corrosion due to the homogeneous microstructure, uniformly refining distributed Mg2Sn phases and smaller amount of block phases.