Temperature dependence of the vacancy sink efficiency of stacking-fault tetrahedra in quenched gold

Abstract

Abstract The average efficiency of stacking-fault tetrahedra as vacancy sinks in quenched gold has been measured over the annealing temperature range from 20°c to 100°c. An electron metallographic technique (Siegel, Balluffi and Thomas 1968) was used for these measurements in which the competition between growing tetrahedra and a free surface for the annihilation of migrating supersaturated vacancies in quenched samples was studied. The measured sink efficiency, ∊, varied from 0·5±0·1 at 20° to 0·9±0·1 at 100°c. Using these results and the previous measurements of ∊ at 60°c a plot of In ∊ versus l/κT was found to be linear with a slope of -0·07 ev. The significance of the observed temperature dependence is discussed in terms of the jog-line (ledge) migration model for the growth of stacking-fault tetra hedra. It is concluded that the climb process leading to tetrahedron growth is thermally activated with an effective activation energy of 0·07 ev. The results are discussed in terms of the relationship between ∊ and investigations of the annealing of vacancy defects in quenched gold.