The diffusion of Bi along various [011] and [001] twist and [001] symmetrical tilt boundaries was investigated as a function of the misorientation angle. The diffusion was measured by observing the intergranular-fracture surfaces of Bi-doped bicrystals. A close correlation was found between the diffusivity at a boundary, and the energy of the boundary for the 3 types of grain boundary. The lowest boundary diffusivity occurred where cusps in the boundary energy existed. The greater the degree of disorder in the atomic arrangement at a boundary, the higher was the boundary diffusivity. Diffusion in [011] twist boundaries took place more easily than that in [001] twist boundaries. In particular, the boundary diffusivity went through a minimum at 28º (S17), 37º (S5), 53º (S5) and 62º (S 17) for [001] symmetric tilt boundaries, 23º (S13A), 28º (S17A), 37º (S5) and 44º (S29A) for [001 twist boundaries and 51º (S11), 59º (S33C), 71º (S3) and 83º (S57B) for [011] twist boundaries.

Grain-Boundary Diffusion of Bi in Cu Bicrystals. R.Monzen, T.Okamoto: Materials Science Forum, 1999, 294-296, 561-4