Anomalous strain hardening behaviour of a supersaturated Al-Zn-Mg alloy

The work hardening behaviour and the evolution of resistivity were simultaneously followed during tensile tests at 300, 77 and 4.2 K, in an Al-Zn-Mg alloy in the as quenched state and in pure Aluminium. In pure Aluminium both the work hardening and the resistivity evolution can be interpreted in terms of dislocation storage and dynamic recovery models. In the alloy, both the work hardening rate and the resistivity evolution are anomalously high. These two effects can be interpreted in terms of dynamic precipitation of GP zones at low temperature during plastic flow.