Twinning, dynamic recrystallization, and texture evolution in as-solution AZ80 Mg alloy during hot compression

Abstract

The characteristics of twins, dynamic recrystallization (DRX), and texture evolution of as-solution AZ80 Mg alloy at different strains, strain rates and temperatures during hot deformation were investigated by EBSD analysis systematically. The activation of twin variants, their interactions, and their role in microstructure and mechanical response are emphasized. The results show that: a large number of {10–12} tension twins and a twin “cross” structure containing three types of twin-twin boundaries (TTBs) were formed at a strain of 0.10, a strain rate of 0.1 s−1, and a temperature of 300 °C. Meanwhile, the original grain is subdivided by high-angle boundaries (HAGBs) converted from twin boundaries (TBs), and the flow stress curve exhibits a feature of concave curvature at a higher strain rate and a lower temperature. As the strain increases, the dominant DRX mechanism is converted from continuous DRX (CDRX) to discontinuous DRX (DDRX) after peak stress, while particle stimulation nucleation (PSN) occurs throughout the process. The strong base texture is weakened by twinning and DRX, where twinning deviates from the parent grain by 86° and DDRX grains deviate from the parent grain by 5°–20°. The diagram of relationships between flow stress and microstructure evolution and texture is established.

Keywords

• Twinning
• Hardening rate
• Grain refinement
• Dynamic recrystallization
• Texture