Self-diffusion in dislocated α-Fe single crystals was studied by using the radioactive tracer, 59Fe, at 754 to 1163K. Serial sectioning was performed by means of microtoming or sputtering (table 9). Based upon previous systematic studies of diffusion along dislocations in the same material, lattice diffusion coefficients were selected by considering the influence of dislocations upon the apparent diffusivities measured in dislocated crystals. The temperature dependence of the lattice self-diffusion coefficient exhibited a deviation from Arrhenius behaviour due to the magnetic order-disorder transition. From fits of various models to a set of lattice diffusion coefficients, the activation parameters for self-diffusion in the ferromagnetic state were found to range from 6.8 x 10−4 to 2.77 x·10−3m2/s and from 2.95 to 3.10eV. The corresponding parameters for the completely disordered paramagnetic state ranged from 6.8 x 10−4 to 1.23 x·10−3m2/s and from 2.57 to 2.68eV.
M.Lübbehusen, H.Mehrer: Acta Metallurgica et Materialia, 1990, 38[2], 283-92
 
Table 9
Self-Diffusion in α-Fe
 
Temperature (K)
Method
D(m2/s)
1163
microtomed
2.85 x 10-15
1137.5
microtomed
1.26 x 10-15
1111
microtomed
8.21 x 10-16
1108
sputtered
4.11 x 10-16
1078.5
sputtered
1.96 x 10-16
1065.5
microtomed
2.10 x 10-16
1064
microtomed
2.20 x 10-16
1054
sputtered
8.10 x 10-17
1032
sputtered
3.14 x 10-17
1031.5
sputtered
3.70 x 10-17
1018
sputtered
1.33 x 10-17
992
sputtered
6.00 x 10-18
962
sputtered
1.12 x 10-18
946
sputtered
5.61 x 10-19
924.5
sputtered
1.47 x 10-19
909
sputtered
1.00 x 10-19
879
sputtered
2.31 x 10-20
840
sputtered
2.14 x 10-21
806
sputtered
3.76 x 10-22
754.5
sputtered
2.70 x 10-23
754.5
sputtered
1.90 x 10-23