Biomedical rare-earth magnesium alloy: Current status and future prospects

Biomedical magnesium (Mg) alloys have garnered significant attention because of their unique biodegradability, favorable biocompatibility, and suitable mechanical properties. The incorporation of rare earth (RE) elements, with their distinct physical and chemical properties, has greatly contributed to enhancing the mechanical performance, degradation behavior, and biological performance of biomedical Mg alloys. Currently, a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents, achieving substantial and encouraging research progress. In this work, a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided. The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed. Particularly, the degradation behavior and mechanical properties, including their underlying action are studied in-depth. Furthermore, the preparation techniques and current application status of RE-Mg alloys are reviewed. Finally, we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.