Issue 36

F. Z. Liu et alii, Frattura ed Integrità Strutturale, 36 (2016) 139-150; DOI: 10.3221/IGF-ESIS.36.14 147 Figure 8. The correlation between 2 ln( / ) P T  and 1/ P T of experimental materials: a) diffusible hydrogen; b) non-diffusible hydrogen). Tab. 6 shows that, activation energy of diffusible hydrogen trap was close to hydrogen activation energy of M 3 C carbide in 42CrMo steel processed at a tempering temperature of 600 °C (13.4 kj/mol) [22] as well as hydrogen trap activation energy of Fe 3 C (18.5 kJ/mol) and hydrogen trap activation energy of grain boundary (17.2 kJ/mol) [23].