高性能超高压镁合金研究进展

Magnesium alloys are the lightest metallic structural materials. The density of magnesium alloys is ~1.7 g/cm³, which is ~2/3 of the aluminum alloy, ~2/5 of titanium alloys, and ~1/4 of steel. Magnesium alloys possess high specific strength, excellent casting performance, excellent biocompatibility, good electromagnetic shielding performance, remarkable damping performance, and ease of recovery. They have broad application potential in aerospace, defense, automobile transportation, biomedical, electronic 3C, construction, and energy fields. China has substantial Mg resources. The development of low-cost and high-performance magnesium alloys in the lightweight field can transform resource advantages into industrial benefits while promoting energy conservation and emission reduction in production and daily life. This is strategically significant for the enhancement of the country ' s technology industry and the achievement of the objectives of“carbon peak and carbon neutrality”. However, commercial magnesium alloys currently possess relatively low strength, poor ductility, and corrosion resistance compared with common metallic structural materials like steel and aluminum alloys, significantly hindering the large-scale industrial application of magnesium alloys as structural materials. Many methods exist to enhance the comprehensive mechanical properties of magnesium alloys. Conventionally, the microstructure of magnesium alloys can be modified by adding alloying elements, plastic deformation, and heat treatment. The strength of magnesium alloys can be improved through grain refinement, work hardening, solid solution strengthening, and precipitation strengthening. Nevertheless, magnesium alloys prepared through these traditional methods can achieve excellent strength but at the expense of ductility, leading to the strength-ductility tradeoff in the magnesium alloy. At present, ultrahigh-pressure (UHP) treatment technology can achieve novel phases and modified microstructures that cannot be prepared under atmospheric pressure. The pressure significantly impacts the thermodynamics and dynamic parameters of metallic materials, such as the equilibrium temperature, critical radius for nucleation, interfacial free energy, chemical potential, entropy, enthalpy and heat capacity, and nucleation rate. Thus, the solid solubility, grain size, morphologies, dislocation density and types, twin types and morphologies, as well as the distribution and morphologies of the intermetallic phases of the magnesium alloys, can be modified using UHP treatment combined with temperature. It offers significant potential for altering the microstructure of magnesium alloys, providing new paths to break the bottlenecks between the comprehensive properties. This paper summarizes the progress of the research on the UHP treatment of high-performance magnesium alloys, the fabrication technology, and the technical characteristics of the UHP treatment. Moreover, the effects of UHP treatment on the mechanical properties, corrosion resistance, and hydrogen storage properties of magnesium alloys by modifying the microstructures of magnesium alloys are emphasized. Finally, the future development directions of the UHP magnesium alloys are explored.