Effects of Strain Rate on Stress-Strain Curves in 2024 Aluminum Alloy After Solution Heat Treatment

Strain rate sensitivity of effective stress and fracture strain of aluminum alloy 2024 were examined considering the period from solution heat treatment. Notched round bar tensile test specimens were employed for obtaining stress-strain curves. Because the necking area of tensile tests is under multiaxial stress, effective stresses of aluminum alloy 2024 were corrected by an optimization method using experimental and simulation results. In the optimization, the experimental and finite element method simulation results of tensile force -true strain of the notched area in the tensile direction were compared. After stress correction, the effective stresses at a true strain of 0.002 were almost the same or showed a small strain rate sensitivity. The effective stresses at a true strain of 0.15 and 0.20 clearly decreased with increasing strain rate and clearly increased at a high strain rate. Fracture strain also decreased clearly with increasing strain rate and clearly increased at a high strain rate.