The migration of Fe in the ' phase of an intermetallic compound with the L12 structure was studied at 1173 to 1598K by using diffusion couples of Ni-24.2Al versus Ni-24.2Al versus Ni-23.7Al-3.52Fe. Diffusion profiles in the annealed diffusion couples were measured by means of electron probe micro-analysis. The diffusion coefficients of Fe in the ' phase of 24.2mol%Al material were deduced from the diffusion profiles by using Hall's method. It was found that the temperature dependence of the diffusion coefficient could be described by:

D(m2/s) =0.027 exp[-347(kJ/mol)/RT]

The activation energies were found to be closely related to the substitution

behavior of  Fe atoms in the L12 lattice sites of '.

Y.Minamino, T.Yamane, S.Saji, K.Hirao, S.B.Jung, T.Kohira: Journal of the Japan Institute of Metals, 1994, 58[4], 397-403