Diffusion kinetics in dilute binary alloys with the h.c.p. crystal structure

In this paper, an extended version of the matrix method is derived in order to address diffusion kinetics for the full anisotropic three-dimensional h.c.p. structure. It is shown that the diffusion anisotropy can be properly addressed with a model of 13 atom-vacancy frequencies which is an extended version of the well-known 5-frequency model for the f.c.c. lattice. Both tracer and phenomenological diffusion coefficients are calculated using this new approach. Extended Monte Carlo simulations are performed in order to cross-check some of the results of the matrix method. Applications of the proposed model to experimental diffusion data are discussed.