The effect of the addition of bismuth on the dynamic recrystallization (DRX) behavior of the matrix has been investigated by comparing coarse grain pure Mg with the addition of 3 wt.% Bi, using a uniaxial compression test in the temperature range of 473–623 K and the strain rate of 0.01–10 s⁻¹. The constitutive equation, processing map, microstructure, and texture evolution of the Mg-3Bi alloy were systematically investigated. The results showed that the Bi addition could refine the grain size and accelerate the DRX process. The DRX kinetics is discussed in detail, accompanied by extensive characterization employing EBSD analysis. The DRX of the Mg-3Bi alloy depended on the deformation temperature rather than the strain rate. The {10–12} tensile twin appeared at 573 K/0.01–0.1 s⁻¹, and discontinuous DRX (DDRX), continuous DRX (CDRX) as the main mechanism in the case of 573 K/0.01 s⁻¹, while the dominant mechanism was DDRX when deformation temperature and strain rate increased. Particle-stimulated nucleation (PSN) was also involved in the DRX of this new RE-free Mg alloy.

In this paper, pre-extrusion treatment was applied to AZ80 alloy prior to caliber rolling, and microstructural evolution as well as mechanical properties of groove-rolled AZ80 alloy were studied. The results shown that the pre-deformation treatment can enhance the formability of AZ80 alloy and the cracking can be avoided. In addition, the pre-extrusion also resulted in fine grain structure after rolling process. Especially, 8-pass caliber rolling following by pre-extrusion of AZ80 alloy shown uniform and fine dynamic recrystallized (DRX) structure. Besides, the introduction of pre-deformation also promotes more second phases during caliber rolling. Therefore, the mechanical properties shown that the yield strength (TYS), tensile strength (UTS) and elongation after fracture (El.) of pre-extruded AZ80 caliber-rolled bars are 250 MPa, 440 MPa and 15%, respectively, which increased by 72%, 37%, and 88% compared with their as-cast counterparts. The improvement of mechanical properties is attributed to synergy effects of grain refinement, second precipitates strengthening and texture optimization.