The effect of nano-hydroxyapatite on the microstructure and properties of Mg-3Zn-0.5Zr alloy

In order to meet the clinical application requirements of biodegradable materials in orthopedic surgery field, novel Mg-3Zn-0.5Zr/xHA (x = 0, 0.5, 1 and 1.5 wt%) composites have been developed by melting under the mechanical stirring and the heat extrusion route. The thorough examination on the effect of nano-hydroxyapatite (nano-HA) particles on the microstructure, mechanical properties and corrosion resistance of Mg-3Zn-0.5Zr alloy was carried out. The results indicated that the gelatin-coated nano-HA particles could more uniformly distribute in the matrix and the grain size was refined to be approximately 10 μm. More non-basal dislocations presented in the composite with the increment of nano-HA particles. Compared with the Mg-3Zn-0.5Zr alloy, the ultimate tensile strength, yield strength and elongation of the Mg-3Zn-0.5Zr/1.5HA composite had been improved and reached 302 MPa, 275 MPa and 20.9%, respectively. Furthermore, Mg-3Zn-0.5Zr/1HA composite showed the optimal degradation rate of 6.45 mm/yr in the in vitro corrosion tests. From the clinical application requirements of biodegradable materials point of view, the composite containing 1 wt% nano-HA particles could be evidently believed to be a promising bone fixation material for the application.