Dynamic recrystallization behavior of 7085 aluminum alloy during hot deformation

The dynamic recrystallization behavior of 7085 aluminum alloy during hot compression at various temperatures (573–723 K) and strain rates (0.01–10 s−1) was studied by electron back scattered diffraction (EBSD), electro-probe microanalyzer (EPMA) and transmission electron microscopy (TEM). It is shown that dynamic recovery is the dominant softening mechanism at high Zener–Hollomon (Z) values, and dynamic recrystallization tends to appear at low Z values. Hot compression with ln Z=24.01 (723 K, 0.01 s−1) gives rise to the highest fraction of recrystallization of 10.2%. EBSD results show that the recrystallized grains are present near the original grain boundaries and exhibit similar orientation to the deformed grain. Strain-induced boundary migration is likely the mechanism for dynamic recrystallization. The low density of Al3Zr dispersoids near grain boundaries can make contribution to strain-induced boundary migration.