The inclination dependence of gold tracer diffusion along a Σ3 twin grain boundary in copper

Abstract

Grain boundary impurity diffusion of Au in diffusion bonded Σ3〈011〉 Cu bicrystals has been studied by the radiotracer serial-sectioning technique using the 195Au isotope with high specific activity. The dependence of the grain boundary diffusion parameter sδD b on the inclination angle Φ of the grain boundary plane with respect to the close-packed (111) plane of the coherent twin boundary has been determined for the temperatures of 673 and 773 K (here s, δ and D b are the segregation factor, the grain boundary width and the grain boundary diffusion coefficient, respectively). At both temperatures sδD b exhibits a minimum at Φ=70.5° and a maximum at Φ=82.0°. It is shown that there is no direct correlation between the energy and diffusivity of the grain boundaries in this system and that the periodicity in the grain boundary plane has a significant influence on the grain boundary diffusivity.