Effect of strain rate and dynamic strain ageing on work-hardening for aluminium alloy AA5182-O

The work-hardening of the solution-strengthened aluminium alloy AA5182-O is studied as a function of strain rate at room temperature. The main aim is to characterize the influence of strain rate and dynamic strain ageing on the work-hardening of the material. Tensile tests with constant nominal strain rates in the range from 10 −6 to 1 s −1 were carried out; additionally, strain-rate jump tests were performed. The material exhibits a sharp yield point, a Lüders plateau, and serrated yielding within the actual range of strain rates. This indicates that the steady-state strain rate sensitivity is negative as a result of dynamic strain ageing. The serrations in the stress–strain curves and the work-hardening are markedly reduced with increasing strain rates. In most cases, the jump tests exhibit the standard behaviour, i.e., after a transient period following the jump in strain rate, the stress–strain curve converges to the steady-state stress–strain curve at the new strain rate.