The Influence of Low Levels of Zinc, Calcium, Gadolinium, Strontium, and Zirconium on the Corrosion of Magnesium for Wrought Applications

Relatively low level additions of Zn, Ca, Gd, Sr, and Zr, to a total alloying content of <3 wt%, were made to Mg in a binary, ternary, quaternary, and quinternary manner to systematically investigate the effect of composition on electrochemical behavior and corrosion. This study contributes to a holistic understanding of the influence of these alloying elements on the corrosion of Mg, both in isolation and combination, with such dilute alloys relevant to wrought Mg products. It was revealed that corrosion of Mg had an ultra-sensitivity to the type and amount of alloying elements in the binary and ternary context, while higher order (quaternary and quinternary) alloying additions were not observed to deteriorate corrosion resistance, such that a relatively consistent range of comparatively low corrosion rates was achievable through quaternary and quinternary alloying. The effect of the thermomechanical processing on corrosion was seen to depend on alloy composition; however, alloy chemistry was more import...