Abstract
A coupled transient hydrogen diffusion-elastoplastic analysis that includes the effect of hydrogen on material softening in the microscale, is implemented to simulate the necking event in the presence of hydrogen. Results show that at the onset of necking, lattice sites are depleted by the increased number of trap sites due to plastic strain localization. When necking occurs, the hydrogen concentration in lattice sites is strongly affected by the loading time. In the presence of hydrogen perturbation, the stress-strain curve measured at the central point of the sample is seen to contain four distinct regions: an initial region of elastic response where the stress is less than initial yield stress; Stage I, a region of easy glide; Stage n, a region of linear hardening; and Stage HI, a region of parabolic hardening. It is worth mentioning that these three stages closely resemble the shear stress-strain response of single crystals.
