Effect of Extrusion Ratios on Microstructure, Microhardness and Corrosion Behavior of Magnesium/Hydroxyapatite Bio-composites

Magnesium, magnesium alloys, and magnesium composites have been studied recently for biomedical applications. In this paper, the effect of hot-extrusion ratios has been studied on microstructure, Vickers microhardness, and corrosion behavior of magnesium/Hydroxyapatite bio-composite. The composite with 2.5 wt% Hydroxyapatite has been fabricated using stir casting method. Then, it was hot-extruded at 350ºC by 5 and 20 extrusion ratios. Regarding to the biomedical application of the composites as biodegradable orthopedic implants, corrosion susceptibility of the samples was examined using potentiostatic polarization measurement in simulated body fluid (SBF). The results show that the hardness of the composite specimen has been enhanced in higher extrusion ratios. Also, grain refinement has been occurred by applying higher extrusion ratios and adding Hydroxyapatite reinforcing particles. Moreover, extrusion ratio as like as reinforcing particles has a considerable effect on corrosion behavior and increases the corrosion resistance.