Dynamic simulation studies were made of diffusion in off-stoichiometric Al-rich Ni3Al (Ni73Al27) at 1300 to 1550K. The interatomic forces were described by Finnis–Sinclair type N-body potentials. Particular attention was paid to the effect of the extra 2% of Al atoms sitting on the Ni sub-lattice as antisite point defects (AlNi) on diffusion. Simulation results showed that Ni atoms mainly diffused through the Ni sub-lattice at the temperatures investigated. Al atoms diffused via both the intra sub-lattice and antistructure bridge mechanisms. The contribution to Al diffusion from the antistructure bridge mechanism decreased at the lower temperature (T<1400K). The presence of antisite point defects (AlNi) enhanced both Al and Ni diffusion in Ni73Al27. The Ni–Al coupled diffusion effect was observed and understood at the atomic level for the first time.

Atomistic Simulations of Diffusion Mechanisms in Off-Stoichiometric Al-Rich Ni3Al. Duan, J.: Journal of Physics - Condensed Matter, 2007, 19[8], 086217