Abstract：The hydrogen induced brittle fracture of 45 steel was studied by uniaxial tension after hydrogen charging with electrochemical method. It is observed that with the increase of hydrogen content, the elongation and average fracture strain decrease, the number of dimples decreases and the quasi-cleavage area increases. However, the change with hydrogen charging time is gradually slowed down, and the ductility and fracture strain of the sample do not change after 144 h of hydrogen charging. According to the experimental observation, the HEDE mechanism and the evolution mechanism of material microvoids affected by hydrogen are introduced into the GTN constitutive model, and the phenomenon that the volume fraction of microvoids nucleation increases with the increase of hydrogen concentration, and the initiation of nucleation and polymerization will be advanced is considered. The results show that with the increase of hydrogen concentration, the elongation and contraction at rupture decrease, and the position of the crack initiation point changes with the change of hydrogen concentration distribution. These results can reasonably explain and reproduce the process and phenomena observed in the experiment.
2022, Vol. 43 
