Biocorrosion behavior and cytotoxicity of a Mg-Gd-Zn-Zr alloy with long period stacking ordered structure

Microstructure, biocorrosion behavior and cytotoxicity of an as-extruded Mg-11.3Gd-2.5Zn-0.7Zr (wt%) alloy were studied, in order to develop new biodegradable magnesium alloy. The microstructure of the as-extruded alloy mainly consists of the refinement grains, a lamellar X phase with the 14H-type long period stacking ordered (IPSO) structure in grain boundaries and the 14H-type IPSO structure within initial grains and refinement grains, and a small amount of beta phase. The as-extruded alloy has high strength at room temperature. The corrosion rate in Hanks' solution is only 0.17 mm/year and the corrosion mode of the alloy is uniform corrosion, which is much better than that of as-extruded Mg-10.2Gd-3.3Y-0.6Zr (wt%) alloy. Moreover, the cell toxicity grade of the Mg-11.3Gd-2.5Zn-0.7Zr alloy is Grade 1, indicating only slightly having cytotoxicity. The desired results indicate the Mg-Gd-Zn-Zr alloy with LPSO structure will become one of novel promising high-strength biodegradable magnesium alloys. (C) 2012 Elsevier B.V. All rights reserved.