The T (H) accumulation and release processes at MnS precipitates and in the surrounding α-Fe matrix at room temperature were studied by means of T autoradiography by using a pseudo-binary alloy of Fe-MnS. The H accumulation at the MnS precipitates at room temperature was clearly observed, but only on limited occasions. The process involved diffusion, solution and trapping in a complex way; including a temperature effect. The T autoradiography proved to be a very good technique for obtaining H area profiles in a near-surface region, whereas it was only a snapshot at a particular time and temperature. It could lead to a totally different interpretation of the accumulation process, without detailed dependences of the H diffusivity and solubility, in inclusion species and α-Fe, upon temperature.

Hydrogen Diffusion and Trapping Process around MnS Precipitates in α-Fe Examined by Tritium Autoradiography. T.Otsuka, T.Tanabe: Journal of Alloys and Compounds, 2007, 446-447, 655-9

 

Table 6

Grain-Boundary Diffusivity of 59Fe in Fe

(type-B kinetics)

 

Temperature (K)

δDgb (m3/s)

1173

2.17 x 10-17

1153

1.99 x 10-17

1123

1.69 x 10-17

1093

1.30 x 10-17

1073

1.36 x 10-17

1053

1.08 x 10-17

1033

3.32 x 10-18

1023

8.90 x 10-19

973

2.29 x 10-19

923

3.34 x 10-20

873

1.20 x 10-20