Development of Biodegradable Mg-Zn Alloys by Grain Refinement Through Extrusion

In this study, we have developed a biodegradable Mg-Zn alloy with good strength and elongation. Various Mg alloys have been developed over the years because of their excellent properties and biodegradability. However, their limited elongation and rapid corrosion limit their widespread use. In this study, a Mg-3 wt.% Zn alloy was developed, and its mechanical and corrosion properties were evaluated. The cast and solution-heat-treated Mg-3 wt.% Zn alloys were extruded from 180 to 350 degrees C. The ultimate tensile strength and yield stress exhibited maximum increase at 180 degrees C, while strain exhibited maximum increase at 200 degrees C. The minimum corrosion rate was also observed at 200 degrees C. However, the alloy extruded at 180 degrees C showed rapid corrosion during in vitro evaluation because of a second phase that precipitated during extrusion. The enhanced performance of the Mg-3 wt.% Zn alloys was attributed to grain refinement, which increased the mechanical properties by grain boundary strengthening and twinning and the corrosion resistance due to the rapid passivation kinetics.