Internal friction measurements in gold after low temperature electron irradiation

Internal friction measurements have been made on electron-irradiated gold. The change in friction as a function of the total integrated electron flux was measured at 80°K and 280°K for an electron energy of 2 Mev. It was found that the results can be explained in terms of dislocation pinning if there are at least two dislocation systems present. After irradiation near 15°K, little or no direct pinning was observed, but on annealing continuous pinning was observed between 25°–75°K. Pinning also occurred in the temperature ranges 170°–220°K, 240°–260°K and 280°–320°K on warming up after irradiations at 80°K. These pinning stages were superimposed on a background of depinning. The ratio of the number of defects reaching the dislocations during the first two pinning stages was found to depend on the electron energy. The results are compared with those found in copper and the similarity suggests that the nature of the irradiation damage is the same in both metals.