The lattice self-diffusion of 59Fe was measured at temperatures ranging from 847 to 1503K (table 39) by using standard radio-tracer methods. It was found that, at temperatures below 1014K, the Arrhenius plot had a downward curvature. This was attributed to B2-type atomic ordering. Overall, the temperature dependence of the self-diffusion coefficient could be described by:

D (m2/s) = 3.2 x 10-5exp{-204(kJ/mol)[1 + 0.1S2]/RT}

where S was the long-range order parameter.

Z.Tôkei, J.Bernardini, P.Gas, D.L.Beke: Acta Materialia, 1997, 45[2], 541-6

Figure 9

Diffusivity of 59Fe in Fe67Al33