Effect of Annealing Parameters on Microstructure and Rare Earth Texture of Extruded Mg-Gd-Y-Zn-Zr Alloy during Alternate Aging-Annealing Process

Based on an alternating aging-annealing process for enhancing strength and ductility of Mg-Gd-Y-Zn-Zr alloy, we further investigated the effects of different annealing parameters on the microstructure and texture of Mg-Gd-Y-Zn-Zr alloy. The results show that the alloy underwent static recrystallization during the annealing process, and the recrystallization ratio and recrystallized grain size increased with increasing annealing temperature and annealing time. During the period, the transition from low-angle grain boundaries to high-angle grain boundaries within the deformed grains and the encroachment of recrystallized grains on the deformed grains were the main recrystallization mechanisms, dislocations were consumed, and the residual stresses were reduced. In addition, after annealing at different temperatures for 5 h, a rare earth (RE) texture with the orientation approximately between [21 over bar 1 over bar \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{1 }\overline{1 }$$\end{document}4]//ED and [21 over bar 1 over bar \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\overline{1 }\overline{1 }$$\end{document}2]//ED was found in all samples, except for the weakened strongly extruded texture. We focused on this phenomenon and found that the strength of the RE texture gradually increased with longer annealing time at 420 degrees C. The formation of this texture was related to the selective growth of grains.