VOLUME DIFFUSION OF IRON IN FE3AL - INFLUENCE OF ORDERING

The lattice self diffusion coefficient of Fe-59 in Fe3Al has been dete rmined in the temperature range 847-1503 K using the classical radio-t racer method. Below 1014 K the Arrhenius plot has a downwards curvatur e resulting from the B2 type of atomic ordering. The temperature depen dence of the self-diffusion coefficient can be described by: D-v = (3. 2(-1.5)(+2.8) x 10(-5)) x exp(-(204 +/- 6.1 kJ/mol) x (1 + (0.1 +/- 0. 03) x S-2)/RT) (m(2)/s) where S is the long-range order parameter. Cop yright (C) 1997 Acta Metallurgica Inc.