Hot deformation mechanism of a rapidly-solidified Al-Zn-Mg-Cu-Zr alloy

This study systematically investigates the flow behavior of 7050 aluminum (Al) alloy produced via spray forming and subjected to a proposed pretreatment through thermal compression tests. The experimental findings reveal that the peak stress increased with decreasing deformation temperature or increasing strain rates. The parameters in the Arrhenius constitutive model were determined and verified by experimental results for spray formed (SFed) 7050 Al alloy. Hot deformation activation energy of the SFed 7050 Al alloy (147.38 kJ/mol) is notably lower than that of cast Al-Zn-Mg-Cu-Zr alloys, which is attributed to factors such as fine grains, low segregation, pores, and dispersed Al 3 Zr induced by pretreatment. Furthermore, processing maps have been constructed at various strains, revealing optimal stable deformation conditions at 300-450 degrees C/0.001-0.15s- 1 and 425-450 degrees C/ 0.2-1s- 1 . Microstructural analysis of deformed samples highlights the critical role of dynamic recrystallization in influencing the stable and unstable areas of the alloy, which may be activated by high temperature and slow strain rate. The hot deformation mechanism of the SFed Al alloy is governed by interactions among eta-Mg(Zn,Al, Cu) 2 precipitates, dispersed Al 3 Zr particles, dislocation structures, and (sub-)grain boundaries.