Isothermal hot compression tests were performed on an Al-4.8Cu-0.25Mg-0.32Mn-0.17Si alloy using a Gleeble-3500 thermomechanical simulator within the temperature range of 350–510 °C and strain rate range of 0.001–10 s⁻¹, achieving a true strain of 0.9. The constitutive equation and hot processing maps were established to predict the flow behavior of the alloy. The hot deformation mechanisms were investigated through microstructural characterization using inverse pole figure (IPF), grain boundary (GB), and grain orientation spread (GOS) analysis. The results demonstrate that both dynamic recovery (DRV) and dynamic recrystallization (DRX) occur during hot deformation. At high lnZ values (high strain rates and low deformation temperatures), discontinuous dynamic recrystallization (DDRX) dominates. Under middle lnZ conditions (low strain rate or high deformation temperature), both continuous dynamic recrystallization (CDRX) and DDRX are the primary mechanisms. Conversely, at low lnZ values (low strain rates and high temperatures), CDRX and geometric dynamic recrystallization (GDRX) become predominant. The DRX process in the Al-Cu-Mg alloy is controlled by the deformation temperature and strain rate.

The influence of Cu addition on the age-hardening response, mechanical properties, and precipitation evolution of Si-rich Al–Mg–Si alloy was investigated by hardness test, room-temperature tensile test, and transmission electron microscopy analysis. The results indicate that the addition of Cu significantly enhances the aging–hardening response of the alloy, promotes the hardness and room-temperature tensile strength under the peak-aged state, and reduces the softening rate during over-aging. The peak-aged tensile strength of the Cu-added alloy (387 MPa) was approximately 9% higher than that of the Cu-free alloy (355 MPa), and the elongation to failure of the Cu-added alloy reached 19%, significantly exceeding the 15% exhibited by the Cu-free alloy. The Cu promotes the precipitation of under-aged and peak-aged β″ strengthening phases within the alloy grains, while also facilitating the formation of lath-shaped Q’ and L phases in peak-aged and over-aged microstructures. This enhances the room-temperature tensile properties of the alloy in the peak-aged state and reduces the attenuation of over-aged properties. Furthermore, Cu influences grain boundary precipitation behavior by promoting the formation of Cu-rich precipitates along grain boundaries and reducing the width of precipitation-free zones (PFZs).

A hot compression simulation was conducted on the Al-7.62Zn-2.22Mg-0.90Cu-0.30Mn-0.09Er-0.13Zr alloy (7E97) within the temperature range of 300~460 °C and strain rate range of 0.001~10 s⁻¹ using a Gleeble-3500 hot simulator. A flow-stress constitutive equation and hot processing maps were established for the alloy, and the microstructural evolution of the alloy after hot deformation was investigated. It was found that the dominant dynamic softening mechanism of the alloy was dynamic recovery, accompanied by minor dynamic recrystallization. The optimal hot processing window for the alloy was determined to be in the ranges of 0.001~0.05 s⁻¹ and 350~410 °C.