Journal of Materials Research and Technology (Nov 2024)

The effects of deformation parameters on the second phases and softening behavior of Al–Zn–Mg–Cu alloys

  • Rensong Huang,
  • Peng Sun,
  • Liexing Zhou,
  • Yelin Zhang,
  • Shanju Zheng,
  • Xiaohong Yuan,
  • Yonghua Duan,
  • Yawei Peng,
  • Mengnie Li

Journal volume & issue
Vol. 33
pp. 2226 – 2243

Abstract

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This study investigates the effects of deformation parameters on the second phase and softening behavior of Al–Zn–Mg–Cu alloy. The results are as follows: Firstly, the area fraction of the intermetallic phase fluctuates between 0.704 ± 0.092% and 1.886 ± 0.231% with varying deformation parameters. Secondly, in the temperature range of 270 °C to 430 °C, the area fraction of the η[Mg(Zn, Al, Cu)2] phase first increases and then decreases with rising deformation temperature, and gradually increases with decreasing strain rate. The highest area fraction is 12.613 ± 0.340% at 350 °C/0.001 s−1, and the lowest is 0.366 ± 0.068% at 470 °C/0.001 s−1. Additionally, the coarsening and dissolution of the η[Mg(Zn, Al, Cu)2] phase accelerate the dynamic recovery softening of the alloy. The sample at 350 °C/0.001 s−1 shows a low-angle grain boundary (LAGBs) percentage of 97.83% and a minimum average dislocation density of 8.493 × 102 μm2. Furthermore, at 470 °C/0.001 s−1, the Al7Cu2Fe phase has a weaker effect on stimulating nucleation and recrystallization, while the most significant promotion occurs at 430 °C/0.001 s−1. In the range of 270 °C to 350 °C and 0.1 s−1 to 0.5 s−1, the Al7Cu2Fe phase mainly stimulates the formation of sub-grains. These findings offer valuable insights for refining the grain size of alloys by regulating the content of the second phase during hot deformation.

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