Microstructural control of Zn alloy by melt spinning - A novel approach towards fabrication of advanced biodegradable biomedical materials

Biodegradable metallic stents that dissolve over time are essential for treating vascular artery disease. Previous designs made from polymers and magnesium have not achieved the required mechanical properties and degradation patterns. Here, we report a novel zinc alloy that possesses a combination of high strength, good ductility, and uniform degradation behavior. The Zn-0.9Cu-0.4Mn-0.01Mg alloy is produced using melt spinning (a rapid solidification technique), compaction, and extrusion to enhance the synergy between strength and ductility. The melt-spun extruded alloy exhibits an elongation to failure of nearly 30% and a tensile strength exceeding 320 MPa, meeting the mechanical performance criteria required for vascular stenting materials. Melt spinning results in weak texture facilitating basal slip dislocations, and promoting ductility, while maintaining high strength. The microstructure of the melt-spun alloy displays a more uniform and finer microstructure as compared to the extruded alloy. The fine grain size and the uniform dispersion of secondary phases contribute to the uniform degradation behavior of the melt-spun extruded alloy, with a corrosion rate of ~ 0.6 mm/year and low corrosion current density of ~ 40 𝜇A/cm². The findings suggest that rapid solidification of zinc alloys through melt spinning is a promising approach for developing biodegradable medical implants of predictable degradation.