Magnesium and magnesium-based alloys are widely used in the transportation, aerospace and military industries because they are lightweight, have good specific strength, a high specific damping capacity, excellent electromagnetic shielding properties and controllable degradation. However, traditional as-cast magnesium alloys have many defects. Their mechanical and corrosion properties cause difficulties in meeting application requirements. Therefore, extrusion processes are often used to eliminate the structural defects of magnesium alloys, and to improve strength and toughness synergy as well as corrosion resistance. This paper comprehensively summarizes the characteristics of extrusion processes, elaborates on the evolution law of microstructure, discusses DRX nucleation, texture weakening and abnormal texture behavior, discusses the influence of extrusion parameters on alloy properties, and systematically analyzes the properties of extruded magnesium alloys. The strengthening mechanism is comprehensively summarized, the non-basal plane slip, texture weakening and randomization laws are comprehensively summarized, and the future research direction of high-performance extruded magnesium alloys is prospected.

The poor corrosion resistance of magnesium alloys is one of the major obstacles to their widespread applications in the engineering field and the medical field. A hot deformation process is the main way to improve the corrosion resistance of magnesium alloys. In the present study, X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD) were used to investigate the micro-galvanic corrosion behavior and film protection mechanism of hot-rolled Mg-2Zn-2Er-0.3Zr-0.3Mn under 25%, 50% and 75% thickness reductions in Hank’s solution. The results revealed that the best corrosion resistance was obtained in the alloy under a 75% thickness reduction, with a corrosion rate of 0.85 mm/y. The improvement in anti-corrosion was due to the coupling effect of a refined microstructure and dense degradation film on the large deformation hot-rolled alloy. Furthermore, the elements Mn and Er participated in the film formation and stabilized the film structure.