1. National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200240, China
2. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China
As the lightest metallic structural material, the ultimate tensile strength of bulk high-strength magnesium (Mg) alloy has exceeded 700 MPa, and the elongation of high-ductility Mg alloys can be up to 35%, Mg alloys show excellent application prospects in aerospace, electronic communications,defence equipment and other fields. However, Mg alloys are still far away from the commonly applied metallic materials, such as steel and aluminium (Al) alloys, with a large gap in mechanical properties. How to maintain high strength and high ductility at the same time is a challenge in the field of Mg alloys. In addition, pure Mg and Mg alloys are also highly susceptible to corrosion, and increasing the strength of Mg alloys usually deteriorates the corrosion resistance. How to balance high strength and high corrosion resistance is also a major challenge of Mg alloys. This work summarizes the research progress of plastic deformation mechanisms and corrosion-resistant behaviours, and focuses on the synergistic mechanism of Mg alloys strength and ductility based on microstructure regulation and the design principle of high-strength-corrosion-resistant Mg alloys. The introduction of microstructures such as precipitated phases and high-density grain boundaries, which effectively impede dislocations motion, can significantly enhance the strength of Mg alloys; the promotion of multiple plastic deformation carriers in Mg alloys is a key method to improve the ductility of Mg alloys; and the suppression of local microelectrodynamic coupling corrosion and the protective property improvement of passive film can effectively improve the corrosionresistant properties of Mg alloys. The design of microstructures is expected to break through the bottleneck of Mg alloys with high strength, superior ductility and good corrosion resistance.