Phase Transformation in Al/Zn Multilayers during Mechanical Alloying

In this work, mechanical alloying of the alternating stacked pure Al and Zn thin foils was accomplished via high-pressure torsion (HPT). In the alloyed Al-Zn system, an exotic phase transformation from hexagonal close-packed (HCP) to face-centered cubic (FCC) was identified. The atomic-scale evolution process and underlying mechanism of phase transformation down to atomic scale are provided by molecular dynamics simulation and high-resolution transmission electron microscopy. The HCP → FCC phase transformation was attributed to the sliding of Shockley partial dislocations generated at the Al-Zn grain boundaries, which resulted in an [21¯1¯0]/[011¯]\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$[2\overline{1}\overline{1}0]/[01\overline{1}]$$\end{document} and (0001)/(111) orientation relationship between the two phases. This work provides a new approach for the in-depth study of the solid phase transformation of Al-Zn alloys and also shed lights on understanding the mechanical properties of the HPT processed Al-Zn alloys.