The Mg–2·5Nd–0·3Zn–0·1Sr–0·4Zr (wt-) alloy was prepared by gravity casting. Solution treatment and extrusion were conducted. The microstructure, mechanical properties, and corrosion behaviour of the alloy under as cast, T4-treated, and as extruded conditions were evaluated using scanning electron microscope, tensile test, microhardometre, immersion test, and electrochemical test. The results show that the as extruded alloy exhibits the highest ultimate tensile strength (231 MPa), elongation (36·6), and microhardness (57·8 HV). The as cast alloy shows the best corrosion resistance because the relative continuously distributed eutectic phase with noble corrosion potential acts as a corrosion barrier. The as extruded Mg–Nd–Zn–Sr–Zr alloy with high ductility and good corrosion resistance is desirable for preparing biodegradable implants.

In order to refine and homogenise microstructure and to improve mechanical properties of the magnesium alloys for biomedical application, the Mg-2.0Nd-0.1Zn-0.4Zr (wt-%, NZ20K) alloy with low amount of alloying elements was processed by double extrusion and aging processes (DEAP). Compared to the NZ20K alloy after once extrusion and aging processes (OEAP), the microstructure becomes finer and more homogeneous, and the elongation is raised up ∼121% by DEAP. Moreover, the yield strength and ultimate tensile strength are improved ∼27 and ∼16% respectively. Additionally, the corrosion rate of the NZ20K alloy by the DEAP is a little slower than that of the OEAP. It can be concluded that the mechanical properties, as well as the corrosion resistance of the NZ20K alloy, are able to be enhanced by the double extrusion and aging processes.