Study of large strain deformation of dilute solid solutions of Al-Cu using channel-die compression

The mechanical properties of pure aluminium, Al-0.2 wt.% Cu and Al-0.4 wt.% Cu at large strains were studied using channel-die compression at three different temperatures: 77, 200 and 295 K. The evolution of the structure was studied by various techniques, including slip line studies, global texture measurements, backscattered electron Kikuchi patterns and TEM. Intense shear banding was observed at large strains and is related to the texture evolution. The mechanical behaviour was interpreted in terms of work hardening rate vs. stress plots (or theta/tau plots). Increasing the temperature leads to a decrease of the initial slope of the theta/tau plot as well as an increase in its concavity. At large strains all materials exhibited a stage of constant work hardening at low rate, or stage IV. The addition of solute was shown to result in an increase of the work hardening rate, which could be represented by a translation of the theta/tau plot on the stress axis. Phenomenological models are proposed for the prediction of the influence of temperature and solute content on work hardening.