PSI - Issue 13

T. Depover et al. / Procedia Structural Integrity 13 (2018) 1414–1420 Author name / Structural Integrity Procedia 00 (2018) 000–000

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The H diffusivity increased from Q&T 1 h < Q&T 2h < as-Q, which was in the opposite order than the amount of available traps (cf. TDS results in Fig. 4). Generally, the H diffusion coefficient decreased with increasing number of available trapping sites indicating the potential of carbides, not only as a way to trap diffusible hydrogen, but also to reduce its mobility in the steel microstructure. An extensive analysis can be found elsewhere (Depover et al. (2016)).

Figure 4: Representative TEM bright field images with corresponding carbides size distribution maps and related TDS spectrum for Fe-C-Ti in the as-Q, Q&T 1h and Q&T 2h condition (heating rate: 600 °C/h).

As-Q Q&T 2h Q&T 1h

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Figure 5: Permeation curves for Fe-C-Ti in the as-Q, Q&T 1h and Q&T 2h condition.