Modelling of the hydrogen embrittlement in austenitic stainless steels

The paper shows the 3D model of hydrogen diffusion in austenitic stainless steel. To model the behaviour of the material a real microstructure of grain boundaries, of dislocation density, of number of vacancy and the states of precipitates is taking in account and implemented in the software (ANSYS). The effect of each single hydrogen trap was physically determined. To improve the affordability of the results a high number of elements and nodes were carried out in the simulation. The purpose of the model is to identify the hydrogen diffusion in different conditions evaluating the weight of each trap in the process. The model allowed to define the hydrogen saturation of the microstructure in different temperature conditions. The results showed that the trapping effect of vacances is negligible at room temperature and their effect increases as the diffusion temperature increases. The main trapping effect is experienced by the grain boundary then by dislocations and then by the lattice. The trapping effect of precipitates has a remarkable dependence on their dimensions.