Cylinders of pure Mg, and the rare earth, were abutted and annealed (500C, 100 or 300h). Point-by-point composition profiles were measured, using energy-dispersive X-ray spectroscopy and a scanning electron microscope, by starting in the pure Mg, passing through the diffusion zone and finishing in the pure rare earth. The intermetallic phases that resulted from interdiffusion were identified and were compared with the limited existing phase diagrams. For each diffusion couple, a plot of concentration versus distance perpendicular to the original plane of contact was obtained and was analyzed by using the Boltzman-Matano method. The interdiffusion coefficients for each set of phases were then calculated, and the results showed that diffusion through the intermetallic phases was much slower than expected in a solid solution.

Analysis of Interdiffusion of Dy, Nd and Pr in Mg. Y.Xu, L.S.Chumbley, G.A.Weigelt, F.C.Laabs: Journal of Materials Research, 2001, 16[11], 3287-92