Self-diffusion in tungsten

Abstract

Self-diffusion in tungsten single crystals has been measured over the temperature range 1700-3400 K (encompassing a range of nine orders of magnitude in the diffusion coefficient $D$). The plot of $\mathrm{ln}D$ vs $\frac{1}{T}$ is curved, and can be fitted by a sum of two exponentials, $D=0.04\mathrm{exp}(\ensuremath{-}\frac{{5.4}_{5}\mathrm{eV}}{\mathrm{kT}})+46\mathrm{exp}(\ensuremath{-}6.9\ifmmode\times\else\texttimes\fi{}\frac{\mathrm{eV}}{\mathrm{kT}})$ ${\mathrm{cm}}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, the first of which probably represents diffusion by single vacancies.