Abstract: Biodegradable Zn alloy fine wires with diameters less than 0.5 mm are suitable for weaving various stents, yet research in this field remains scarce. High-strength biodegradable Zn-0.6Cu-0.2Li-0.05Mg (ZCLM09) alloy wires in a diameter of 0.3 mm are developed for application in the uterine environment. After extrusion and multi-pass cold drawing, Zn grains are refined from 125.93 to 0.42 µm, and the wires exhibit yield strength of 257 MPa, tensile strength of 341 MPa, and elongation to failure of 43 %, better than most biodegradable Zn alloy wires. The distribution of Li atoms is characterized by three-dimensional atomic probe and time-of-flight secondary ion mass spectrometry. A novel (Li, Mg)₂Zn₁₁ phase is identified for the first time. Its volume fraction is 2.3 %, with a potential 90 mV lower than that of the Zn phase. This novel phase facilitates the degradation of the alloy wires. Immersed in simulated uterine fluid for 28 days, corrosion products are Zn-rich and Li-rich products. And corrosion rate of the wires decreases from 1.31 mm/y at day 1 to a stabilized state of 0.15-0.2 mm/y after day 14. After 28 days of immersion, the weight loss reaches 14.5 %. Viabilities of mouse fibroblast cells cultivated in 10 % extracts within 7 days are all over 100 %, indicating good cytocompatibility. The wires also show an excellent antibacterial property against Staphylococcus aureus and Escherichia coli. The newly developed ZCLM09 alloy wires are promising candidates for intrauterine stents to prevent intrauterine adhesion.

Key words: Biodegradable Zn alloy wires, Microstructure, Mechanical properties, Corrosion behavior, Biocompatibility