Effects of Various Doping Treatments upon the Damage Production and Recovery of Deuteron-Irradiated Aluminum

The effects of various doping treatments (cold work, alloying, and/or radiation doping) upon the damage production and recovery of Al irradiated with 20-MeV deuterons have been investigated. Four of a total of six specimens (two made from Al-0.03 at.% Zn alloy, one annealed, and one cold-worked) were irradiated with 10-MeV protons to a total dose of 3.3×${10}^{16}$ $\frac{p}{{\mathrm{cm}}^2}$ at a temperature of about 90°K and annealed for 10 min at 180°K. These four radiation-doped and two additional specimens (one annealed and one cold-worked) were then irradiated simultaneously at a temperature not exceeding 8°K with 20-MeV deuterons to a total integrated dose of 4.85×${10}^{15}$ $\frac{d}{{\mathrm{cm}}^2}$. Isochronal annealing measurements were carried out in situ up to 265°K. Within our accuracy (±10%), the damage production in all six specimens was the same; however, previous experiments indicate a small increase in damage production for doped specimens. No radiation annealing was found in the annealed 99.9999% Al, while a large effect was found in the cold-worked 99.999% Al. Radiation doping produces the radiation-annealing effect in an annealed sample as well as in the alloy, and reduces the effect of cold working. Cold work and alloying reduce the recovery in stage I; radiation doping increases it. The annealing curves for alloys are smoothed out in stage II. Cold work and/or radiation doping do not affect stage II significantly, and all remaining damage anneals out in stage III. Because all six specimens underwent exactly the same thermal history, the difference in annealing, i.e., the percentage of damage left in specimen $A$ minus the percentage of damage left in specimen $B$, was calculated for different specimen combinations and plotted. These curves reveal many small details in the different annealing behavior which have not been observed previously and which are caused by the different treatments prior to the irradiation. They are discussed in terms of interstitial migration in stage I. Specifically, it is claimed that the crowdion migrates at a temperature of about 45°K and that stage III is composed of (at least) three different annealing processes.