Effect of twinning and Al–Nd phase on dynamic recrystallization in rolled Mg–Al–Zn–Nd alloy at the moderate strain rate

Abstract

The dynamic recrystallization of Mg–Al–Zn–Nd alloy during moderate strain rate rolling was studied using electron backscatter diffraction (EBSD) and an energy dispersive spectrometer (EDS). The results showed three kinds of twinnings produced in the alloy in the strain rate range of 4.2 s ^−1 ∼7.3 s ^−1 , including $\{10\bar{1}2\}$ extension twinning, $\{10\bar{1}1\}$ contraction twinning, and $\left\{10\bar{1}1\right\}-\{10\bar{1}2\}$ double twinning. The extension twinnings decreased gradually with the increase of strain rate. The dynamic recrystallization mechanisms during hot rolling under moderate strain rate conditions mainly include grain boundary nucleation, twinning nucleation, and secondary particle assistant nucleation. The dynamic recrystallization mechanism induced by twinning is mainly $\left\{10\bar{1}1\right\}-\{10\bar{1}2\}$ double twinnings. In addition, the strain value near the Al–Nd phase and grain boundary is higher than in grain. The Al–Nd particles in Mg–Al–Zn–Nd alloy play an auxiliary nucleation effect on dynamic recrystallization during hot rolling deformation.

Keywords

• rolled Mg–Al–Zn–Nd alloy
• twinning
• Al–Nd phase
• dynamic recrystallization