A study was made of the diffusion phenomena in Ni2Y, transition-metal intermetallic phase via a nearly-free electron tight-binding bond interatomic interaction model. Interpretations of the dynamic structures, based on calculations of the mean square displacements and spectral densities of velocity, showed that the rapid growth of this intermetallic phase found in the experimental study was due mainly to the high-rate self-diffusion in and near the grain-boundaries and independent of the vacancy. Therefore, the standard vacancy-based diffusion process was found to be non-essential in this phase.

Molecular Dynamics Simulations of the Self-Diffusion Phenomena in Ni2Y Intermetallic Phase. Hachiya, K., Ito, Y.: Journal of Alloys and Compounds, 1998, 279[2], 171-8