Hot Deformation Analysis and Microstructure Evolution of a Novel Al–Cu–Li Alloy by Isothermal Compression

The hot deformation behavior of a novel Al–Cu–Li alloy is investigated by isothermal compression with a temperature range of 350–510 °C and a strain rate range of 0.001–10 s⁻¹. Constitutive analysis and hot processing maps are used to analyze the influence of deformation parameters on hot deformation behavior, and the related microstructure evolution is characterized by scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM) observations. The results indicate that the microstructure evolution of the alloy during deformation was dominated by dislocation movement and substructure evolution. With the increase in temperature or the decrease in strain rate, the dislocations introduced by deformation gradually transform into dislocation walls and substructures, showing distinct dynamic recovery (DRV) and slight dynamic recrystallization (DRX) characteristics. The degree of DRX is very low, while it is more sensitive to strain rate than temperature. According to the analysis of hot processing maps and microstructure, the optimum deformation temperature and strain rate of the alloy are determined as at least 430 °C and 0.008–0.15 s⁻¹, respectively. These results can be referable for the industrial thermomechanical processing of this novel Al–Cu–Li alloy.