Strength retention, corrosion control and biocompatibility of Mg-Zn-Si/HA nanocomposites

Owing to the poor load-bearing ability and apparent cytotoxicity of polymeric and ceramic materials, magnesium-based materials can be an ideal substitute for bone repair applications. Magnesium is bioresorbable, unlike other metallic materials like titanium and stainless steel, has excellent biocompatibility, compressive strengths and elastic modulus similar to the natural bone, which circumvents the need for secondary surgery post-implantation in vivo. Against this background, in this study, magnesium-based nanocomposites were developed by using hydroxyapatite bioceramic as a nano reinforcement. Magnesium-based alloys were synthesized using selective alloying elements and hydroxyapatite incorporated nanocomposites were processed using the disintegrated melt deposition technique. The microstructure characterization revealed that the addition of hydroxyapatite resulted in superior grain refinement of the magnesium alloy matrix. The addition of hydroxyapatite improved the yield strength of the alloy matrix and displayed superior strength and ductility retention post corrosion for 21 days, under compression loading. The presence of hydroxyapatite improved the hydrophilicity of the alloy matrix thereby aiding the biocompatibility properties with improved corrosion resistance, level 0 cytotoxicity, and high cell attachment. Hence, the present study strongly suggests that magnesium alloy-based hydroxyapatite nanocomposites can be a suitable candidate for bone repair applications.