Microalloyed Zn-Li-Mn-Ca-Si Alloys: Tailoring Microstructure, Degradation Kinetics, and Osteogenic Potential for Biodegradable Orthopedic Implants

Biodegradable zinc-based alloys have emerged as promising candidates for orthopedic implants due to their desirable degradation behavior and essential biological functions. However, the poor mechanical properties and uncontrolled degradation process of pure zinc limit its clinical application. In this study, two multi-element micro-alloyed zinc-based materials (Zn-0.1Li-0.5Mn and Zn-0.1Li-0.5Mn-0.5Ca-0.1Si), were successfully prepared via melting and hot-rolling processes. The effects of alloying elements and thermomechanical processing on the microstructure, mechanical properties, degradation behavior, and biocompatibility were systematically investigated. Experimental results demonstrated that the addition of lithium (Li) and manganese (Mn) significantly enhanced the strength and ductility of the materials. The further introduction of calcium (Ca) and silicon (Si) elements improved strength and hardness, albeit at the expense of plasticity. Homogenization treatment leads to a more uniform distribution of the second phase, and the hot-rolling process refines the grains, thus improving the corrosion resistance of the material. Although the Zn-0.1Li-0.5Mn-0.5Ca-0.1Si alloy exhibited an accelerated degradation rate, it promoted the formation of calcium-phosphorus (Ca-P) compounds, which is beneficial for osseointegration. Both alloys demonstrated good antibacterial properties and cytocompatibility, with the Zn-0.1Li-0.5Mn-0.5Ca-0.1Si alloy showing enhanced osteogenic potential. This study provides an important foundation for the development of high-performance biodegradable zinc-based implant materials.