NUMERICAL SIMULATION OF THE INFLUENCE OF HYDROGEN ON SMALL FATIGUE CRACK GROWTH MECHANISMS IN AISI304L

摘要

To understand the influence of hydrogen on the small fatigue crack growth in the metastable austenitic stainless steel AISI304L, a microstructurally based model is implemented including different crack propagation mechanisms. The polycrystalline microstructure and the elastic anisotropic properties of each grain as well as the crack growth along slip bands are considered. It is assumed that the local hydrogen concentration influences the activation of slip bands and the corresponding yield stress. During the cyclic loading, the hydrogen distribution will be updated taking into account local hydrostatic stresses. Furthermore, the deformation-induced phase transformation from γ-austenite to α'-martensite in the vicinity of the crack is considered.