Effect of isothermal compression and subsequent heat treatment on grain structures evolution of Al-Mg-Si alloy

• Published in: Journal of Central South University Vol. 28; no. 9; pp. 2670 - 2686
• Main Authors: Li, Ze-cheng, Deng, Yun-lai, Yuan, Man-fa, Zhang, Jin, Guo, Xiao-bin
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.09.2021; Springer Nature B.V
• Subjects: Aluminum base alloys; Constitutive relationships; Deformation; Dislocation density; Dynamic recrystallization; Energy storage; Engineering; Evolution; Grain boundaries; Grain size; Heat treating; Heat treatment; Magnesium; Metallic Materials; Misalignment; Silicon; Strain; Al-Mg-Si alloy; dislocation; 再结晶; recrystallization; grain boundaries; Al-Mg-Si 合金; 位错; Zener-Hollomon 参数; 晶界; Zener-Hollomon parameter
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-021-4801-z

The constitutive relationships of Al-Mg-Si alloy deformed at various strain rates, temperatures and strains were studied. The microstructure evolution was quantitatively characterized and analyzed, including recrystallization fraction, grain sizes, local misorientation, geometrically necessary dislocation and stored strain energy during hot deformation and subsequent heat treatment. The results show that the dislocation density and energy storage are linear with lnZ during hot deformation and subsequent heat treatment, indicating continuous recrystallization occurring in both processes. With higher lnZ, the dislocation density declines more sharply during subsequent heat treatment. When lnZ is less than 28, dislocation density becomes more stable with less reduction during subsequent heat treatment after hot deformation. As these dislocations distribute along low angle grain boundaries, the subgrain has good stability during subsequent heat treatment. The main recrystallization mechanism during hot deformation is continuous dynamic recrystallization, accompanied by geometric dynamic recrystallization at higher lnZ.