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.