Characterization and modeling of the high temperature flow behavior of aluminum alloy 2024

AbstractIsothermal flow curves were determined for aluminum alloy 2024-0 at temperatures of 145 to 482 °C and at constant true-strain rates of 10-3 to 12.5 s-1 using compression tests of cylindrical specimens. The average pressure was corrected for friction and for deformation heating to determine the flow stress. At 250 °C and above, the isothermal flow curves usually exhibited a peak followed by flow softening. At 145 °C the flow curves exhibited strain hardening. For 250 °C≦ T<= 482 °C, 10-3 s-1 ≦ $$\dot \varepsilon $$ ≦ 12.5 s-1, and ε ≦ 0.6 the flow behavior was represented by the constitutive equation σ =K (T, ε) $$\dot \varepsilon ^{m\left( {T,\varepsilon } \right)} $$ where logK andm are simple functions of temperature and strain. The as-deformed microstructures generally supported the idea that flow softening in Al 2024-0 is caused by dynamic recovery. At the higher temperatures and strain rates, however, fine recrystallized grains were observed in local areas near second phase particles and at as-annealed grain boundaries. At 482 °C, there was evidence of re-dissolution of the CuMgAl2 precipitate.