Effect of pretreatment on precipitation of Al3Zr dispersoids and recrystallization behavior of spray deposited Al-Cu-Li alloy

The effects of pretreatment on the precipitation behavior of Al3Zr precipitates and the recrystallization of spray-deposited Al-Cu-Li alloy were investigated by scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction. It was found that the distribution of Al3Zr dispersoids in the spray-deposited Al-Cu-Li alloy was heterogeneous. The dispersoid number density is higher in the intragranular and lower near the grain boundaries. The precipitation-free zones are distributed in the intragranular and near the grain boundaries, while a small number of linear clusters are distributed near the grain boundaries. During the homogenization process, the interaction between Zr atoms and dislocation climb caused the precipitation of Al3Zr dispersoids by fast pipe diffusion. Pretreatment of thermal deformation before homogenization increased the number of dislocations in the matrix, promoted the precipitation of Al3Zr dispersoids, inhibited local PFZs, improved the particle distribution, and uniformly distributed Al3Zr dispersoids. After compression by 30% at 673 K, compared with annealing at 573 K for 12 h and compression by 10% at 673 K, the Al3Zr dispersoids have higher number density, more uniform distribution, and smaller size. After hot compression and solution treatment, the percentages of HAGBs in the three hot compression samples were 30.3%, 21.6%, and 17.3%, respectively.