BIODEGRADABILITY AND MECHANICAL PERFORMANCE OF HYDROXYAPATITE REINFORCED MAGNESIUM MATRIX NANOCOMPOSITES

摘要

Magnesium and its alloys have gained significant attention recently as potential alternatives for biodegradable materials due to their good biodegradability, biocompatibility and mechanical properties. However, magnesium alloys tends to have high corrosion rates in biological liquid, thus presenting a potential problem if a magnesium implant/device needs to maintain the mechanical integrity for a sufficient period under physiological conditions. It is expected that nanoparticles could help address this problem. In this study, hydroxyapatite (HA) nanoparticles were used to form magnesium-based metal matrix nanocomposites (MMNC) through friction stir processing (FSP). Microstructural study shows the HA nanoparticles were well dispersed in the magnesium matrix. While FSP alone refined grain size for magnesium, the addition of HA nanoparticles was much more significant for grain refinement. In-vitro corrosion tests were conducted in simulated body fluid (SBF), and experimental results indicated that corrosion resistance of MMNC was much improved when compared to pure Mg. The microhardness of nanocomposites was improved significantly. The study suggests that magnesium nanocomposites yield great potential for enhancing both mechanical properties and corrosion resistance for biological applications.