Characterization of dynamic microstructural evolution ofAA7150 aluminum alloy at high strain rate during hot deformation
(1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Department of Materials Science and Engineering, McMaster University,
1280 Main Street West, Hamiltion, Ontario L8S 4L7, Canada;
3. Hunan Province Key Laboratory for Spray Deposition Technology and Application,
Hunan University, Changsha 410082, China)
2. Department of Materials Science and Engineering, McMaster University,
1280 Main Street West, Hamiltion, Ontario L8S 4L7, Canada;
3. Hunan Province Key Laboratory for Spray Deposition Technology and Application,
Hunan University, Changsha 410082, China)
Abstract: TheAA7150 aluminum alloy was compressed to various strains at strain rate of 10 s-1 and temperatures of 300 °C and 450 °C, respectively. Flow stress behavior, substructure evolution, morphology and spatial distribution of precipitates were studied based on differential scanning calorimetry analysis and transmission electron microscope observation. The results showed that dynamic flow softening occurs during hot deformation. The main softening mechanism could be concluded as dynamic recovery at 300 °C and continuous dynamic recrystallization at 450 °C. The clear heterogeneous spatial distributions of precipitates are found during deformation and enhanced with increased strain. Higher contents of Cu in T phases are found at 450 °C than at 300 °C, which present a transformation process from T phases to S phases as well. The associated evidence of dynamic precipitation on dislocations and particle-stimulated nucleation, as well as the detailed microstructural inherited relationship and morphological texture (particles preferred orientation) were characterized.
Key words: Al-Zn-Mg alloy; hot compression; dynamic phenomena; microstructure