An extended version of the matrix method was derived in order to address diffusion kinetics for the full anisotropic three-dimensional hcp structure. It was shown that the diffusion anisotropy could be properly addressed with a model of 13 atom-vacancy frequencies which was an extended version of the well-known 5-frequency model for the fcc lattice. Both tracer and phenomenological diffusion coefficients were calculated using this approach. Extended Monte Carlo simulations were performed in order to cross-check some of the results of the matrix method.

Diffusion Kinetics in Dilute Binary Alloys with the HCP Crystal Structure. A.R.Allnatt, I.V.Belova, G.E.Murch: Philosophical Magazine, 2014, 94[22], 2487-504