Grain boundary diffusion of ${}^{110m}$Ag in Cu $\Sigma 5\left(310\right)$ bicrystal is measured along and perpendicular to the $\left[001\right]$ 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 $P=s·\delta ·D_{\mathrm{gb}}$ are measured in the B regime (here $s$ and $\delta$ 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 $s·\delta$ for the $\Sigma 5\left(310\right)$ grain boundary is estimated.

• Received 27 January 2012

DOI:https://doi.org/10.1103/PhysRevB.85.144104