Analysis of Low-Temperature Interstitial Migration Kinetics in Copper

A quantitative analysis of the recovery kinetics of stage ${\mathrm{I}}_E$ in copper is made following 2-MeV electron irradiation using dose-dependent temperature shifting. The doses considered range from about 3×${10}^{-8\mathrm{}}$ to about 2×${10}^{-6\mathrm{}}$ concentration of defects. Over this range the order of kinetics is found to increase with increasing dose from 1.2 to 1.6, with the higher value appearing to be an asymptotic value for increasing dose. The variation of the order of kinetics over this dose range is explained using nominal second-order kinetics influenced by excess vacancy concentrations produced by interstitial trapping by residual impurities. The functional dependence of the kinetics upon the initial concentrations of defects is demonstrated. A discussion of interstitial recovery behavior is extended for all doses in terms of the amount of damage remaining at the end of stage I. The results are also discussed in conjunction with several current annealing models.