Hot deformation behavior of 2026 aluminum alloy during compression at elevated temperature

Hot compression tests of 2026 aluminum alloy were carried out on Gleeble-1500 system in the temperature range from 300 °C to 450 °C and at strain rate range from 0.01 s−1 to 10 s−1, and the associated microstructural evolution was studied by observations of metallographic and transmission electron microscope. The results show that the true stress–true strain curves exhibit a peak stress at critical strain, after which the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by the Zener–Hollomon parameter Z in the hyperbolic sine equation with the hot deformation activation energy of 340.98 kJ/mol. The hot deformed microstructure consists of a great amount of precipitate within subgrains in the elongating grains develops and may be associated with the Z value. At low Z value, the subgrains remain well formed with clean high-angle boundaries and coarse precipitates are distributed in the grain interior. At high Z value, a high dislocation density with poorly developed cellularity and considerable fine dynamic precipitates are observed.