Dislocation characteristics and dynamic recrystallization in hot deformed AM30 and AZ31 alloys

Zn addition to Mg alloys activates non-basal slip or twinning with solute softening effects. On the other hand, the effects of the Zn solute on the macroscopic dislocation behavior and dynamic recrystallization are not completely understood. Moreover, it is unclear if slip can be affected by changes in the c/a ratio of solute atoms. This study was conducted to understand the solute strengthening of Zn addition and its effects on the dislocation characteristics and dynamic recrystallization. A hot torsion test was performed on both AM30 and AZ31 alloys up to a high strain to investigate the Zn solute effect on the dislocation characteristics and dynamic recrystallization. The dislocation components of the hot torsioned alloys were evaluated by X-ray line profile analysis and electron backscatter diffraction. The results showed that the Zn solutes slightly accelerate strain accumulation at the initial stages of hot deformation, which accelerated recrystallization at high strain. The dislocation characteristics were changed dynamically by Zn addition: fortified -type slip, dislocation arrangement and strain anisotropy parameters. The most important point was that the dislocation characteristics were changed dramatically at the critical strain for recrystallization and high strain regions. The addition of Zn also acted greatly in these strain areas. This indicates that the rapid formation of -type slip at the serrated grain boundaries occurs at the initiation of dynamic recrystallization and the increase in the grain triple junction because grain refinement has a great influence on the dislocation characteristics at high strain. (c) 2022 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under responsibility of Chongqing University

Automated summary

This study investigated the solute strengthening effect of Zn addition in Mg alloys and its impact on dislocation characteristics and dynamic recrystallization. The results showed that Zn solutes accelerate strain accumulation and recrystallization, and dynamically change the dislocation characteristics. Zn addition is particularly influential at the critical strain for recrystallization and in high strain regions.