Effects of Extrusion on Mechanical and Corrosion Resistance Properties of Biomedical Mg-Zn-Nd-xCa Alloys

Magnesium alloys act as ideal biomedical materials with good biocompatibility. In this paper, the extruded biomedical Mg-6Zn-0.5Nd-0.5/0.8Ca alloys were prepared and their microstructure, mechanical properties and corrosion properties were investigated. The results showed that the surfaces of Mg-6Zn-0.5Nd-0.5/0.8Ca alloys extruded at medium temperature were smooth and compact without cracks. The tensile strength and elongation of Mg-6Zn-0.5Nd-0.5/0.8Ca alloys were 222.5 MPa and 20.2%, and 287.2 MPa and 18.4%, respectively. A large number of dislocations were generated in the grains and on grain boundaries after the extrusion. The alloy was immersed in simulating body fluid (SBF) for the weightlessness corrosion, and the corrosion products were analyzed by FTIR, SEM equipped with EDS. It was found that the corrosion rate of Mg-6Zn-0.5Nd-0.5Ca and Mg-6Zn-0.5Nd-0.8Ca alloy were 0.82 and 2.98 mm/a, respectively. Furthermore, the compact layer was formed on the surface of the alloy, which can effectively hinder the permeation of Cl&minus
and significantly improve the corrosion resistance of magnesium alloys.