Synergistic mechanical-degradation coupling in novel immiscible Mo-Cu alloy for biodegradable implant applications

Mo alloys have emerged as a promising biodegradable metallic material due to its inherent biocompatibility and mechanical robustness. However, its clinical translation is limited by slow degradation kinetics and intrinsic brittleness. In this study, we propose a powder metallurgy-based strategy to develop immiscible Mo-Cu alloys that overcome these challenges. Cu is introduced as alloying element which due to higher corrosion potential, excellent plasticity and antimicrobial properties. The optimized Mo-Cu alloy shows a notable increase in strength by 150 MPa while maintaining ductility. Moreover, the degradation rate nearly doubles from 2.553×10 -2 to 4.765×10 -2 mm/y) due to microstructural refinement and galvanic effects. In vitro studies further confirm the biocompatibility and enhanced antibacterial performance of Mo-Cu alloys. This work provides a practical pathway for designing next-generation biodegradable implants based on immiscible alloy systems.