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 (LPSO) structure in grain boundaries and the 14H-type LPSO structure within initial grains and refinement grains, and a small amount of β 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.

► Mg–11.3Gd–2.5Zn–0.7Zr (wt%) alloy with LPSO structure was studied as biomaterial.
► Biocorrosion rate of the alloy is only 0.17 mm/year and it shows uniform corrosion.
► Alloy induces only slight cell toxicity to L-929 cell.