LOW-TEMPERATURE RECOVERY OF DEFORMED ALUMINUM

Abstract

The isochronal recovery of deformed polycrystalline Al was measured from 4 to 300 °K by means of residual electrical resistivity measurements. A well-defined recovery stage was observed between 60 and 100 °K (stage II_A); it has also been observed after neutron irradiation, but not after electron irradiation (Sosin 1963). This stage was enhanced by increasing the deformation or introducing quenched-in vacancies, and was suppressed by impurity atoms. These results can be explained by di-interstitial migration. The recovery below 60 °K (stage I) amounted to approximately 5%, and was independent of impurity content or degree of deformation. Both stage I and stage II_A recovery were greatly increased by a prior deformation and low-temperature anneal. A similar increase was observed for Au. This enhancement was attributed to a change in deformation mechanism because of dislocation pinning, which resulted in the formation of a preponderance of interstitial defects.