Abstract:

The use of press hardening steel (PHS) in the critical parts of body-in-white has experienced a rapid growth in the automotive industry. Challenges exist when small concentration of diffusible hydrogen significantly deteriorates the material mechanical properties. However, coupling of martensitic transformation and hydrogen diffusion often meets difficulties due to lack of knowledge on hydrogen diffusion in martensitie structure. In this seminar, we will discuss a 2D model which coupling the phase field model together with the hydrogen diffusion model to illustrate the preferable distribution site of hydrogen in martensite structure. The model involves a solid mechanics module and several PDE modules.Boundaries with high hydrostatic stress and a large content of dislocation exhibit high risk of fracture. Furthermore, the modelling result is able to give good predication on PHS fracture modes by comparing the local hydrogen concentration with the critical value.