Recovery Study in Pure and Alloyed Aluminum Following Electron Irradiation

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Abstract
Pure aluminum and slightly alloyed aluminum samples were bombarded with electrons near 4.2 and 78°K. The electrical resistivity increases introduced by the radiation were observed to recover in three stages: Stage I, below 50°K, Stage II centered at about 140°K, and Stage III, between 190 and 250°K. Stage III follows second-order kinetics with an activation energy of 0.45±0.01 eV; Stage II follows close to first-order kinetics with an activation energy of 0.22 eV. The magnitude of Stage II depends sensitively on the amount and type of solute atoms in the lattice. Stage III is larger in alloyed aluminum than in pure aluminum and is shifted to lower temperature. The enhanced magnitude and the temperature shift are consistent with the observed second-order kinetics, indicating that the effect of alloying is to increase the number of defects which migrate in Stage III. A two-interstitial model, previously proposed to explain recovery in copper following irradiation, appears to account for these observations most satisfactorily.