Simulation of Hydrogen-Induced Cracking Behavior of Austenitic Stainless Steel 316L With Phase-Field Method

Hydrogen-induced cracking (HIC) is one of the main failure modes of hydrogen after entering the material. In this paper, the hydrogen-induced fracture behavior of austenitic stainless steel (316L) was studied, electrochemical hydrogen charging and mechanical testing of 316L were carried out, the stress-strain curves of samples before and after hydrogen charging were analyzed, and a phase-field model of hydrogen embroilment fracture was established to study the hydrogen-induced fracture behavior of 316L based on weak bond theory, Fick's law, and energy phase-field formula. The numerical results show that hydrogen can significantly reduce the material's tensile strength and fracture strain, resulting in the loss of plasticity. Under the action of applied load, hydrogen is enriched in the stress concentration position, which increases the hydrogen concentration in this area, reduces the atomic bonding force and the critical energy release rate, increases the damage of the material, and causes damage fractures. The length-scale parameter (l) has no effect on the crack path, and the increase of the l will lead to the reduction of the maximum bearing capacity of the specimen. The hydrostatic pressure distribution is consistent with the hydrogen concentration distribution, and the hydrogen concentration is enriched at a higher hydrostatic pressure before the material is completely damaged and fractured, while the hydrogen concentration at the tip of the new crack decreases after the material fails and fractures.