The effect of Mg on the metallurgical, mechanical, and cytocompatibility properties of potentially-biodegradable Zn-4Ag-0.8Cu for cardiovascular stent

This study investigates the potential of ternary and quaternary zinc (Zn) alloys for biodegradable cardiovascular stent applications, focusing on enhancing mechanical properties through alloying. Three Zn-4Ag-0.8Cu-xMg (x = 0, 0.5, and 1 wt%) alloys were fabricated using casting, homogenization, and extrusion. Magnesium (Mg) addition produced a clear strength–ductility trade-off. With increasing Mg content from 0 to 1 wt%, yield strength/ultimate tensile strength (YS/UTS) increased from 72.8/86.4 to 124.4/129.9 MPa in the as-cast state, from 60.1/69.2 to 88.9/129.1 MPa in the as-homogenized state, and from 107.1/208.6 to 203.6/305.3 MPa in the as-extruded state, while elongation to failure (EL) decreased from 10.2 to 5.1%, 21.8 to 11.7%, and 39.9 to 6%, respectively. Phase analysis identified α-Zn, AgZn 3 , and Mg 2 Zn 11 phases, along with weak reflections possibly associated with trace CuZn 5 . The improved strength and hardness were attributed to the increased fraction of brittle Mg 2 Zn 11 intermetallic phases and the extrusion-induced fragmentation and redistribution of secondary phases. Cytotoxicity tests showed that extruded alloys were biocompatible at dilutions of 50% and 10% without any significant difference between the alloy types ( p > 0.05). Among the investigated alloys, the extruded Zn-4Ag-0.8Cu-0.5Mg alloy exhibited the most balanced strength–ductility response, showing YS, UTS, and EL values of 203.4 MPa, 244.8 MPa, and 17%, respectively, which makes it potent for cardiovascular stent applications.