Effect of Zn Content on Biodegradable Mg Alloy Synthesized via Mechanical Alloying for Biomedical Application

The aim of this work was to study the effect of zinc content on biodegradable binary magnesium-zinc (Mg-Zn) alloy synthesized using mechanical alloying. A powder mixture of Mg with the different content of Zn (3, 5, 10 and 15 wt%) was mechanically milled at constant rotational speed of 250 rpm for 5 h. At low Zn content up to 5 wt%, the Mg-Zn alloy mainly consisted of α-Mg matrix. However, with higher addition of Zn from 10 wt% and further, the intensities of α-Mg peaks decreased and secondary phase of γ-MgZn was identified as the solid solubility limit of Zn in Mg was only 6.2 wt% at 340 °C. The sintered density and microhardness of the alloy increased as a function of Zn content due to its higher elemental density, thus restraining the growth of crystal grains and refine the crystal grains of Mg.