Achieving higher dynamic mechanical response by adjusting texture through twinning in a ZK61 Mg alloy

In this study, texture c-axis//ND of ZK61-T6 Mg alloy was reoriented towards c-axis//ED, TD and tilted in between ED and TD in a ZK61-PC Mg alloy through cross pre-compression. Subsequently, quasi-static and dynamic mechanical behaviour was examined. The results showed that compressive yield strength, ulti-mate compressive strength and elongation to fracture were considerably increased from 140 to 220 MPa, 374-437 MPa and 0.15-0.16, respectively. This increase was the synergistic effect of texture, grain refine-ment through twin boundaries and pre-induced dislocation hardening effect. In addition, an exceptional increase of ultimate compressive strength (531 MPa) was obtained under dynamic loading. The micro-structure evolution of deformed specimens revealed that the propensity and width of the adiabatic shear band were increased with an increase in strain rate in ZK61-PC Mg alloy. In addition, twinning, de-twin-ning, < a > and < c+a > dislocation inside the twin and the matrix absorbed the high-stress energy and provided a higher mechanical response in ZK61-PC Mg alloy. The twinning induce rotational dynamic re-crystallization mechanism was responsible for the development of fine grains. Based on the results, it is recommended that pre-compression is a practical way to increase the efficiency of the ZK61 Mg alloy. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, the reorientation of texture and improvement of mechanical properties in ZK61-T6 and ZK61-PC magnesium alloys were achieved through cross pre-compression. The results showed that the compressive yield strength, ultimate compressive strength, and elongation to fracture were significantly increased. The microstructure evolution revealed the propensity and width of adiabatic shear band and the role of twinning, de-twinning, and dislocation in absorbing high-stress energy. The twinning-induced rotational dynamic recrystallization mechanism contributed to the development of fine grains. Based on the findings, pre-compression is recommended as a practical approach to enhance the efficiency of ZK61 magnesium alloy.