The production and annealing of point defects produced by quenching and by tensile deformation in pure gold and silver

Gold specimens of six nines purity were strained at 4.Z K by tensile deformation and were quenched from 700 ± 40 oC. For gold deformed at 4.ZoK the most prominent annealing is observed in the region between ZOoC and 70°C. For this case the annealing at 40°C obeys second order kinetics and the effective energy of migration, which increases with increasing purity, is 0.90 ± .04 eV for specimen of highest purity. For fast quenched gold (dT/dt = 5 x 10^4 to 5 0 .00 1.1 x 10 C/sec) the stage III annea1ing occurs from 40 C to 100 C. The annealing obeys second order kinetics and the effective energy of migration increases from 0.80 eV to 0.90 eV as the residual resistivity at 4.Z o K decreases from 9.5 x 10 -100 cm to 4.Z x 10 -10 0 cm. For slow dT 3 4 0 . quenched gold (dt = 7 x 10 to Z x 10 C/sec) the annea1~ng follows first order kinetics and the activation energy of migration is 0.70 ± .04 eV. The stage III annealing in deformed and fast quenched gold is attributed to the migration of a single vacancy in the presence of a high density of sinks. The results are shown to be consistent with an annealing theory which assumes that the divacancy has a high binding energy and that the value of sink density is important in determining the rate limiting process for the annealing. Fr~m the annealing kinetics of fast quenched gold and by using high temperature diffusion and thermal equilibrium data, the binding energy of a divacancy is calculated to be 0.35 < B < 0.52 eV. Some tensile deformation experiments were done on 99.9999% pure silver. The annealing is found to be much more complicated as compared with gold and stage III activation energy is 0.70 ± .04 eV. The identity of defects taking part in stage III in silver is not clear at the present time.U of I OnlyThesi