Analysis of Self-Diffusion and Quenching Studies in Aluminum and Gold

Abstract
The analysis of available experimental data for self-diffusion in Al and Au shows that the apparent activation energy increases with increasing temperature. It is shown that this behavior cannot be due only to a divacancy contribution to the high-temperature diffusivity, since this contribution would have to be too large. An explanation which is consistent with the results of quenching studies can be formulated in terms of a temperature dependence of the motion enthalpy Hm1v of single vacancies. In Al, Hm1v is found to increase from 0.46 to 0.72 eV between 225 and 650°C, and in Au from 0.71 to 0.83 eV between room temperature and 1025°C. The conclusions of this investigation are especially important for the identification of quenched-in defects and for the study of thermally activated processes in general.