The growth of body-centered cubic Fe-Co precipitates on [011] twist boundaries with misorientation angles of between 10 and 80º was investigated in samples which had been aged at 723, 748 or 773K. The aging-time dependence of the average particle radius could be described by rn = Kt, where K was a constant. Except for a 10º boundary in bicrystals which had been aged at 773K, the value of n was 4. This was in agreement with theories of grain-boundary precipitate coarsening. In the exceptional case, n had a value of between 3 and 4. The results were explained by taking account of the relative contributions of bulk diffusion and grain-boundary diffusion to particle growth. A good correlation was found between the activation energy, for particle growth on a boundary, and the energy of the boundary. A higher-energy boundary was associated with a higher diffusivity.

R.Monzen, T.Hasegawa: Philosophical Magazine Letters, 1997, 76[2], 69-75