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Magnesium alloys have attracted significant attention due to their excellent characteristics, such as low density, high specific strength, high thermal conductivity, and superior damping ability. The prominent advantages of using magnesium-alloy parts are environmental protection, energy conservation, and emission reduction, especially forged magnesium-alloy parts, which are used to reduce the weight of equipment in transportation and aerospace fields. Presently, there are relatively few investigations on the forged Mg-RE alloys. Based on Mg-Gd binary alloy, a series of Mg-Gd-Er-Zr alloys were developed, exhibiting excellent room-temperature mechanical properties and high-temperature creep resistance. In this study, the Mg-8Gd-1Er-0.5Zr (mass fraction, %) alloy was conducted using a multidirectional forging (MDF) at a high strain rate. The microstructure and texture evolution in various accumulated strains (Sigma Delta epsilon) were examined, and their effects on the mechanical properties of the alloy were discussed. The results showed that the {10 (1) over bar2} extension twinning was activated within most grains in the early stage of forging. With an increase in Sigma Delta epsilon, the area fraction of twin decreases, while the area fraction of recrystallization increases. Continuous dynamic recrystallization (CDRX) was the dominant mechanism, supplemented by discontinuous dynamic recrystallization (DDRX) and twin-induced recrystallization (TDRX). The grain refinement was attributed to the twin-breaking, and the grain size decreased from 33.0 mm to 13.1 mu m when Sigma Delta epsilon was less than 1.32. However, it was attributed to the dynamic recrystallization, and the grain size was further refined to 4.2 mu m when Sigma Delta epsilon was greater than 1.32. As Sigma Delta epsilon increases, the texture of the alloy changed from basal to double-peak texture, and its intensity increased. When Sigma Delta epsilon = 0.66, the tensile strength, yield strength, and elongation at room-temperature of the MDFed-alloy reached 295 MPa, 252 MPa, and 13.8%, respectively, which were 80%, 157%, and 13.1% higher than those of the assolution state.
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