Large strain work hardening in the alloy Al–1Mg–1Mn at low and intermediate deformation temperatures: experiments and modelling

Samples of the commercial alloy Al–1 wt.%Mg–1 wt.%Mn (AA3004) have been subjected to deformation by compression at different temperatures T=0.3–0.5 Tm (Tm is the melting temperature in K) and equivalent strain rates from 10−3 to 10 s−1. Dislocation densities and volume fractions of cell interior areas have been measured by means of X-ray diffraction peak profile analysis. Clearly, the hardening characteristics exhibited stages IV and V of deformation. The hardening curves have been fitted by two different models basing on the composite ansatz by Mughrabi, i.e. that by Mülders and that by Zehetbauer and Les. Fit results from both models are in good agreement with the measured dislocation densities and volume fractions of cell interior areas. The fits also give strong hints to the participation of deformation-induced vacancies in the deformation process. In contrast to pure Al, the actual alloy exhibits only a weak dependence of the dislocation density and vacancy concentration on the deformation temperature, which seems to be a consequence of the presence of alloy atoms restricting diffusion and dislocation movement.