Microstructure, Mechanical Properties and Corrosion Fatigue Behaviour of Biodegradable Mg–Zn–Y–Nd Alloy Prepared by Double Extrusion

The application of biodegradable Magnesium (Mg) alloy implants is limited due to their insufficient corrosion fatigue resistance. This work investigated the influence of double extrusion on the microstructure, mechanical properties and corrosion fatigue behaviour of Mg-Zn-Y-Nd alloy. The results showed that, after double extrusion, the texture intensity was significantly weakened and a more uniform microstructure with fine grain size was obtained. The double extruded alloy showed improved mechanical properties with a yield strength of 196.5 MPa, an ultimate tensile strength of 241.8 MPa and an elongation up to 29.7%. As compared to that of single extruded Mg-Zn-Y-Nd alloy, the fatigue tests indicated that double extrusion improved the fatigue strength of the alloy by 23% in air and 20% in simulated body fluid. Based on the results, the mechanisms of fatigue and corrosion fatigue of double extruded Mg-Zn-Y-Nd alloy were presented.