The migration of Cu, Fe, and Si in the ' phase of an intermetallic compound with the L12 structure was studied at temperatures ranging from 1173 to 1598K by using diffusion couples of Ni-24.2Al versus Ni-24.1Al-4.73Cu, Ni-24.2Al versus Ni-23.7Al-3.52Fe, and Ni-24.2Al versus Ni-22.3Al-3.14mol%Si. Diffusion profiles in the annealed diffusion couples were measured by means of electron probe micro-analysis. The diffusion coefficients of Cu, Fe, and Si 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 dependences of the diffusion coefficients could be described by:

Cu:     D(m2/s) = 0.0055 exp[-323(kJ/mol)/RT]

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

Si:     D(m2/s) = 0.48 exp[-390(kJ/mol)/RT]

The activation energies were found to be closely related to the substitution behavior of Cu, Fe and Si 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