Tracer diffusion of 54Mn in alloy D9 in presence of sodium

The diffusivity of manganese in vacuum annealed and cold worked alloy D9 in presence of sodium was measured by the standard tracer technique. The lattice diffusion coefficient of manganese in vacuum annealed alloy D9 specimens in the temperature range 773–873 K is given by the expression D = ( 2.24 - 2.07 + 26.45 ) × 10 - 14 exp ( - 60 764 ± 17 403 / RT ) m 2 s - 1 and that in cold worked alloy D9 specimens is given by D = ( 4.62 - 3.77 + 20.77 ) × 10 - 16 exp ( - 38 880 ± 12 006 / RT ) m 2 s - 1 where R is in J K−1 mol−1. The activation energy for diffusion in cold worked specimens is less than that in vacuum annealed specimens. The activation energy for diffusion of manganese in presence of sodium is almost four times less than that in various austenitic stainless steels reported in the literature.