Hot tensile deformation mechanism and microstructure evolution of Mg-2Nd alloy with heterostructure

The deformation mechanism and microstructure evolution of the extruded Mg-2Nd alloy were investigated in the hot tensile deformation process at strain rate of 2.2 x 10-4 s-1 and deformation temperatures of 150 degrees C-300 degrees C. the results showed that the peak stress declines and the elongation to fracture increases with the increasing of deformation temperature. By observation of the microstructure, the fibrous extrusion zones (FEZs) and non-fibrous extrusion zones (non-FEZs) coexist in the alloy, and the microstructure deformation of the FEZs is more obvious than that of the non-FEZs. In the initial deformation stage, the grain deformation first occurs in the FEZs. In the later deformation stage, recrystallization occurs in both FEZs and non-FEZs. Moreover, the deformation mechanism of the FEZs is different from that of the non-FEZs. The deformation mechanism of the FEZs is dominated by intragranular slip, supplemented by grain boundary slip (GBS). The recrystallization mechanism in FEZs is continuous dynamic recrystallization (CDRX). On the contrary, the deformation of the nonFEZs is dominated by GBS, while the intragranular slip plays a coordinated role. The recrystallization mechanism in non-FEZs is discontinuous dynamic recrystallization (DDRX). Therefore, the dominated hot tensile deformation mechanisms of the alloys are alternated among intragranular slip, GBS and dynamic recrystallization (DRX)

Automated summary

The deformation mechanism and microstructure evolution of the Mg-2Nd alloy during hot tensile deformation were investigated. It was found that the peak stress decreases and the elongation to fracture increases with increasing deformation temperature. The alloy contains fibrous extrusion zones (FEZs) and non-fibrous extrusion zones (non-FEZs), with the microstructure deformation in the FEZs being more pronounced. In the initial deformation stage, grain deformation occurs primarily in the FEZs, while recrystallization occurs in both FEZs and non-FEZs in the later deformation stage. The dominant deformation mechanism in the FEZs is intragranular slip, supplemented by grain boundary slip (GBS), while the dominant deformation mechanism in the non-FEZs is GBS, with coordinated intragranular slip. The recrystallization mechanism in the FEZs is continuous dynamic recrystallization (CDRX), while it is discontinuous dynamic recrystallization (DDRX) in the non-FEZs. Thus, the dominant hot tensile deformation mechanisms of the alloys alternate between intragranular slip, GBS, and dynamic recrystallization (DRX).