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

Abstract

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.

Keywords

Al-Cu-Li alloy / spray-deposition / pretreatment / Al₃Zr dispersoids / recrystallization

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