Effect of Zn on mechanical properties and corrosion behaviours of Mg-Zn alloy

摘要

This study investigated three as-cast Mg-Zn binary alloys to reveal the individual effect of Zn additions on the microstructure, mechanical property and the corrosion behaviour. Zinc content from 1 to 5 wt.% was beneficial to improving the mechanical property and corrosion resistance of magnesium alloy. It was revealed that additions of Zn to Mg significantly refined the grain size of Mg matrix and increased the volume percent intermetallic in the microstructure. The corrosion morphologies and immersion tests as well as electrochemical measurements proved the corrosion resistance increased with the increasing of Zn content in the range 1-5 wt.% despite the presence of the potentially detrimental MgZn intermetallic. Excessive addition of Zn over 7 wt.% resulted in network structure of MgZn intermetallic as a cathode, causing micro-galvanic corrosion acceleration. As a consequence, the addition of Zn content has to be controlled to promote both the mechanical properties and corrosion resistance of Mg alloys for biomedical application.