Abstract
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 ((phi = 5.69 x 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. (C) 2011 Elsevier B.V. All rights reserved.