Diffusion and segregation of silver in copperΣ5(310) grain boundary

Abstract

Grain boundary diffusion of ${}^{110m}\phantom{\rule{-0.16em}{0ex}}$Ag in Cu $\ensuremath{\Sigma}5(310)$ bicrystal is measured along and perpendicular to the $[001]$ tilt axis in both C and B kinetic regimes after the common Harrison's classification. The grain boundary diffusion coefficients, ${D}_{\mathrm{gb}}$, of the single grain boundary in a true dilute limit of solute concentration are determined in the C kinetic regime and the values of the triple products $P=s\ifmmode\cdot\else\textperiodcentered\fi{}\ensuremath{\delta}\ifmmode\cdot\else\textperiodcentered\fi{}{D}_{\mathrm{gb}}$ are measured in the B regime (here $s$ and $\ensuremath{\delta}$ are the segregation factor and the diffusional grain boundary width, respectively). A strong anisotropy of the grain boundary diffusion is established, which disappears above 826 K. It is the point at which the triple product $P$ demonstrates a downward deviation from the otherwise linear Arrhenius dependence at lower temperatures. These results substantiate a temperature-induced disordering transition of the grain boundary structure. The anisotropy of the product $s\ifmmode\cdot\else\textperiodcentered\fi{}\ensuremath{\delta}$ for the $\ensuremath{\Sigma}5(310)$ grain boundary is estimated.