Recent advances in high-temperature oxidation behavior and underlying mechanisms of Mg-RE alloys: a comprehensive review

Poor high-temperature oxidation resistance of magnesium (Mg) alloys is a key factor restricting their development and application. The addition of some rare earth elements (REs), due to their unique physical and chemical properties, can greatly enhance the oxidation resistance of Mg alloys. According to our prior work, we can summarize that the REs like Gd, Y, and Ce will effectively enhance the oxidation resistance of Mg-RE alloys. This article comprehensively reviewed recent research progresses on the high-temperature oxidation behavior and its potential mechanism in Mg-RE alloys. Based on the thermodynamic and kinetics analyses, the evolution of complex oxide system formed during high-temperature oxidation of Mg-RE alloys was firstly summarized. The diffusion behavior and concentration control mechanisms of REs in the course of oxidation process, and how these mechanisms affect the sustained growth of oxide film and the antioxidant properties were elucidated as well. Moreover, the different structures of oxide film were classified and the various properties of oxide film were also discussed. Finally, this paper introduced the applications of commonly used REs in Mg alloys and the frontier researches on the oxidation mechanism. Based on the above review work, we proposed that the future research perspectives can be explored in terms of expanding the experimental temperature range for oxidation tests, optimizing chemical composition by adding trace REs to study their synergistic mechanism, revealing the underlying oxidation mechanism through advanced in-situ microscopic characterization methods, and investigating the mechanical properties of oxide film with diversified approaches.