Diffusion of Cu, Fe, and Si in the Ni3Al phase (γ′) of an intermetallic compound with L12 structure has been studied at temperatures from 1173 to 1598 K using the diffusion couples of (Ni-24.2 mol%Al/Ni-24.1 mol%Al-4.73 mol%Cu), (Ni-24.2 mol%Al/Ni-23.7 mol%Al-3.52 mol%Fe), and (Ni-24.2 mol%Al/Ni-22.3 mol%Al-3.14 mol%Si). The diffusion profiles in the annealed diffusion couples were measured by an electron probe microanalyzer. The diffusion coefficients of Cu, Fe, and Si in γ′ of 24.2 mol%Al were evaluated from the diffusion profiles by Hall’s method. The temperature dependence of the diffusion coefficients (m2/s) is presented as follows:
(This article is not displayable. Please see full text pdf.)
\
oindentThe activation energies are found to be closely related to the substitution behavior of Cu, Fe and Si atoms in the L12 lattice sites of γ′.
