Recovery of work-hardening of SAP alloys

The temperature region of recovery of four aluminium alloys containing 2.4, 3.7, 8.3 and 11.9 wt% Al 2 O 3 is given in dependence of the alumina content and the degree of deformation. It is found that the alloys containing 8.3 and 11.9 wt% Al 2 O 3 recover on annealing one hour below or just at the melting point of pure aluminium. The absolute increase of Vickers hardness due to deformation with respect to the recovered state is independent of the Al 2 O 3 content and as high as in strongly deformed aluminium. The recovery of the electrical resistivity above the temperature of liquid nitrogen was investigated and in recovery stage III two activation energies were found. These activation energies are attributed to divacancy (0.35 eV) and to interstitial migration (0.58 eV), by comparison with results known from pure aluminium.