Influence of alloyed Al on the microstructure and corrosion properties of extruded Mg-8Sn-1Zn alloys

Microstructure and corrosion properties of extruded Mg-8Sn-1Zn alloys with varying Al contents were investigated. Microstructures of the extruded alloys mainly consisted of ??-Mg grains and Mg2Sn particles in common. Addition of Al to the ternary alloy resulted in the formation of different types of Al-Fe-based intermetallic particles depending on Al contents. In 0.6M NaCl solution, the extruded alloys with 1-3wt% Al showed over 30 times higher corrosion rates than those containing less than 0.3wt% Al; this discrepancy was attributed to the presence of Al5Fe2 particles acting as strong cathodic sites for H2 evolution during corrosion. ??? 2015 Elsevier Ltdclose1