Quenching-in and annealing of point defects in silver

Abstract

Quenching-in and annealing of point defects in 99.999% silver were studied by following changes in electrical resistivity. Upon quenching from temperatures, T _Q, between 550 and 650°c the resistivity increased according to : Δ_ρ° = 8.5×10⁻⁴ exp (−1.10/kT _Q) ohm cm. Above 650°c the resistivity increases were less than predicted by this equation due to losses of defects to sinks. The quenched-in defects were extremely mobile, showing appreciable recovery in minutes at sub-zero temperatures. The low activation energy (0.57 ev) associated with this annealing indicates that the defects involved may be divacancies. Because their annealing rate is too high to be accounted for by loss at permanent sinks, and because a large residual resistivity remains after the low-temperature annealing is complete, it appears that the defects are associating to form clusters. The clusters remain stable up to about 200°c where a second annealing stage occurs. The dissolution of clusters in this stage is associated with an activation energy of 1.18 ev.