Synthesis of Biodegradable Mg-Zn Alloy by Mechanical Alloying: Effect of Milling Time

Magnesium (Mg) is one such promising light weight metal, which is currently utilized for bio-engineering applications. Mg possesses a number of attractive characteristics that make Mg-based materials potential candidates to serve as implants for load-bearing applications in the medical industry due to its good biocompatibility and biodegradability. However, Mg and its alloys are susceptible to suffer attack in chloride containing solutions, e.g. the human body fluid or blood plasma. Thus, alloying with other metal elements is the most effective tool to improve mechanical properties and corrosion resistance of Mg. In this current work, binary Mg-Zn alloy was produced using mechanical alloying (MA) followed by compaction and sintering. The aim of this work was to study the effect of milling time on binary magnesium-zinc (Mg-Zn) alloy synthesized by mechanical alloying. A powder mixture of Mg and Zn with the composition of Mg-10wt%Zn was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 250 rpm for various milling times i.e. 1, 2, 5, 10 and 15 hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400 MPa and sintered in a tube furnace at 350 °C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Zn solid solution and formation of MgZn₂ when Mg-Zn powder was mechanically milled for 2 hours and further. A prolonged milling time has increased the density and microhardness of the sintered Mg-Zn alloy.