Self-diffusion was measured in single crystals of the -phase, at 1540 to 1697C, by using 26Al as a radiotracer. It was found that 2 diffusion mechanisms were involved. These were a lattice diffusion mechanism and a sub-boundary mechanism. The latter data could be described by:

D(cm2/s) = 1.3 x 1014 exp[-202(kcal/mol)/RT]

The Al diffusion coefficients were greater than the O diffusion coefficients in sub-boundaries.

M.Le Gall, B.Lesage, J.Bernardini: Philosophical Magazine A, 1994, 70[5], 761-73