The grain-boundary impurity diffusion of Au along the incoherent twin boundary in a diffusion-bonded Cu bicrystal was studied by using a serial sectioning technique. It was found that the measured penetration profiles had an atypical form, which was explained in terms of the structural multiplicity of the grain-boundary structure. A method of processing such profiles was suggested, and the relative fraction of the grain-boundary structural modification which exhibited the lowest diffusion coefficient (table 39) was estimated to be 60%. The difference between the energies of the 2 structural modifications was estimated to be less than 17%, and this figure was in good agreement with the results of computer simulations of the grain-boundary energy of Cu.

E.Rabkin, C.Minkwitz, C.Herzig, L.Klinger: Philosophical Magazine Letters, 1999, 79[7], 409-15