Texture evolution during dynamic recrystallization in a magnesium alloy at 450°C

Structure of grain boundaries with 30°[0 0 0 1] misorientation in dynamically recrystallized magnesium alloys

“…Mayama et al [34] showed that, as the grains rotate around h2 1 1 0i or h1 0 1 0i, the rotation may stabilize at a specific misorientation angle when the plastic spin generated by the pyramidal and the basal slip is cancelled out. Ma et al [4] performed crystal plasticity simulation and the results showed that the combination of these three slip systems tend to bring the orientations of the grains toward the [0 0 0 1] and h2 1 1 0i. So in the RaD specimen, the mechanism for the 30°[0 0 0 1] GB appears to be more complicated than the ED specimen.…”

“…In the ED specimen, extension twinning is the primary deformation mode even at elevated temperatures [33], but the deformation twins were quickly consumed by new DRX grains [4]. Unless the strain rate is considerably high, the effect of twinning on the texture is insignificant [4]. The dominant slip mode that was activated during deformation is prismatic slip.…”

“…At elevated temperatures, the critical stresses for the non-basal slip systems are significantly reduced [4]. As the crystals rotates, basal slip and prismatic slip may also be activated.…”

“…During deformation and recrystallization, the plastic spin of the grains stabilizes at this misorientation angle around the rotation axis [0 0 0 1]. In the ED specimen, extension twinning is the primary deformation mode even at elevated temperatures [33], but the deformation twins were quickly consumed by new DRX grains [4]. Unless the strain rate is considerably high, the effect of twinning on the texture is insignificant [4].…”

“…Due to the hexagonal close-packed (HCP) crystal structure, the ductility of Mg alloys is limited at room temperature [1]. To improve the ductility and formability, Mg alloys are often processed at raised temperatures at which dynamic recrystallization (DRX) occurs [2][3][4]. Mg alloys have a strong tendency to develop basal texture in which the basal planes of the crystals are reoriented to the direction roughly parallel to the processing direction, for example, the rolling direction (RD) or the extrusion direction (ED) [1].…”