Synergistic enhancement: realizing superior strength, ductility and degradation performance in pure magnesium

Pure magnesium (Mg) has been widely used in orthopedic medical materials due to its biodegradability and excellent biocompatibility. However, it is difficult to realize pure Mg in clinical procedures due to its poor mechanical properties and non-uniform degradation. Grain refinement is the main strengthening mechanism of pure Mg, and uniform degradation can be achieved by fine-grained microstructure. In this work, the Mg with the average grain size of 3.62 μm was prepared by the low-temperature secondary extrusion in a well-controlled Zener-Hollomon parameter of $${e}^{34.9}$$ . The fine-grained Mg shows high strength (215 MPa), ductility (20.4%), and low degradation rate (0.18 mm/y), satisfying the requirements of bone load-bearing regions. The degradation mechanisms of different grain-sizes Mg in physiological solutions were also investigated. This work demonstrates that fine-grained Mg exhibits uniform degradation due to less matrix contact with the solution and compact product layers, thus providing a new approach to developing highly corrosion-resistant Mg alloys.