The migration of 54Mn in single crystals of α-phase material was measured, at 878 to 1135K, by using tracer methods. It was found that Mn exhibited a rapid diffusion behavior, and diffused at a rate which was some 3 orders of magnitude greater than that for self-diffusion. The temperature dependences of the diffusivity parallel to, and perpendicular to, the c-axis could be described by:

parallel:     D (cm2/s) = 4.9 x 10-2 exp[-38.2(kcal/mol)/RT]

perpendicular:     D (cm2/s) = 6.0 x 10-1 exp[-45.1(kcal/mol)/RT]

It was found that the presence of O suppressed Mn diffusion. This was attributed to a blocking effect of O.

Y.Nakamura, H.Nakajima, S.Ishioka, M.Koiwa: Acta Metallurgica, 1988, 36[10], 2787-95