Research progress on rare earth-containing heat-resistant magnesium alloys

Magnesium alloys hold considerable promise for lightweight structural applications due to their low density and high specific strength. However, their intrinsic hexagonal close-packed crystal structure results in a limited number of active slip systems, inadequate high-temperature strength, poor creep resistance, and pronounced flammability. These inherent drawbacks significantly restrict their utilization in demanding high-temperature and severe service environments, such as those encountered in aerospace and transportation sectors. To overcome these performance limitations, alloying with rare earth elements has proven to be an effective strategy. This article provides a detailed analysis of the regulatory effects and underlying mechanisms by which rare earth elements influence the microstructure of magnesium alloys. It further examines the critical roles and mechanisms by which RE additions significantly enhance properties such as creep resistance, superplasticity, fatigue life, and flame retardancy. The discussion also extends to the synergistic effects achieved by composite alloying with elements such as Al, Zn, and Ag, or by the incorporation of nanoparticle /metallic particles, which collectively contribute to multiple strengthening mechanisms. Future research should focus on the design of Mg alloys with low or even zero heavy rare earth content, the in-depth elucidation of multiscale structure-property relationships, the integration of advanced processing technologies, and the development of lifetime prediction models under extreme environments. These efforts will be essential for promoting the reliable application of magnesium alloys in a wider range of high-temperature structural scenarios.