An overview was presented of atomic diffusion in three nickel-based L12 ordered intermetallic compounds, Ni3Al, Ni3Ga and Ni3Ge. Data on the diffusion of constituent species and those of chemical diffusion were accumulated by radioactive tracer experiments and single-phase interdiffusion experiments. The tracer diffusion coefficients of the majority component, Ni, in the three compounds were of the same order of magnitude when normalized to the melting temperature, while in contrast, those of the minority component were widely different. Nevertheless, it appeared to be possible to understand these common and distinctive features in terms of a simple model of diffusion, wherein both of the two species of atoms diffused primarily over the sub-lattice of the majority component via the ordinary vacancy mechanism.

Diffusion in Ni3Al, Ni3Ga and Ni3Ge. Numakura, H., Ikeda, T., Nakajima, H., Koiwa, M.: Materials Science and Engineering A, 2001, 312[1-2], 109-17

Figure 7

Self-diffusion of Al and Ni in Ni3Al

White circles, Ni; black circles, Al