The diffusion of 59Fe was studied by using serial sectioning and autoradiographic techniques at 1020 to 1500K (volume diffusion) and 750 to 1100K (grain boundary diffusion). The bulk diffusivity (table 170) could be described by:
1020-1500K: D (m2/s) = 3.26 x 10-5 exp[-259.6(kJ/mol)/RT]
The grain boundary diffusion coefficients were usually evaluated by using Whipple’s method. In a few cases, Suzuoka’s method was used. The grain boundary diffusivities (table 171) could be described by:
750-1100K: D (m2/s) = 1.88 x 10-5 exp[-160.7(kJ/mol)/RT]
A.R.Paul, M.C.Naik, K.N.G.Kaimal: Materials Science and Technology, 1991, 7[1], 8-11
Table 168
Apparent Room-Temperature Diffusivity of H in Irradiated HY-80 Steel
Specimen | H Surface Concentration (ppm) | D (cm2/s) |
non-irradiated | 7.5 | 6 x 10-6 |
non-irradiated | 9.6 | 6.4 x 10-6 |
non-irradiated | 10.2 | 8.3 x 10-6 |
irradiateda | 13.25 | 4.4 x 10-6 |
irradiateda | 11.5 | 1.33 x 10-6 |
irradiateda | 13.0 | 2.2 x 10-6 |
a: dose = 4 x 1017n/cm2, energy >1MeV