Effect of torsional oscillations on the stress–strain behavior of Al–5 wt% Mg alloy

► Imposing torsional oscillations increased creep parameters. ► The variation in creep parameters with increasing aging temperatures, was due to the structural changes. ► Activation energy values were attributed to a precipitate-dislocation intersection mechanism is operating. The microstructure and mechanical properties of a precipitation hardenable Al–5 wt% Mg alloy subjected to low frequency torsional oscillations and aging treatments are reported in the present work. The stress–strain response was examined at different frequencies (1.53–3.3 Hz) and at constant shear strain amplitude ( φ = 5.69 × 10 −4). An excessive in the softening was observed by increasing both frequency of the applied oscillations and deformation temperature. The change in the hardening and softening parameters of stress–strain relations was explained in view of spinodal decomposition in Al–Mg systems. The mean value of activation energy was found to be equal to that quoted for precipitate–dislocation intersection.