Influence of hydrogen on the deformation behaviour of a ferritic fine-grained low alloy steel

Steels are subjected to various atmospheres which can affect their strength, deformation and damage behaviour at room temperature as well as at increased temperature. These alterations are due to micromechanical effects which will influence the dislocation behaviour in the material. Also, hydrogen atoms dissolved in the material are often the reason for these changes. Therefore, modelling the impact of hydrogen atoms is of interest in understanding the material behaviour in hydrogen containing environments. example, the influence of hydrogen on the material behaviour of the steel 15MnNi 6-3 at room temperature is demonstrated experimentally and numerically: Tensile tests and JR-tests show that pressurised hydrogen changes the ductility and crack resistance. As well the damage behaviour of the material is described. Moreover, atomistic simulations help to get some insight how hydrogen atoms impede the movement of dislocations. The Rousselier model and a modified decohesion model for taking the influence of hydrogen into account are combined in order to macroscopically analyse the damage behaviour of hydrogen affected round notched tensile and Compact Tension (C(T)) specimens.