Influence of hydrogen core force shielding on dislocation junctions in iron

Haiyang Yu and Ed Tarleton report in Physical Review Materials  a study of the influence of hydrogen on dislocation junctions by incorporating a hydrogen-dependent core force into nodal-based discrete dislocation plasticity simulations. Hydrogen-induced softening was reproduced at a realistic bulk concentration commonly seen in experiments. Due to its short-range nature, the hydrogen core force shielding mechanism has a pronounced influence on the activity of dislocation junctions. In microcantilever plasticity simulations, the hydrogen core force shielding mechanism caused an increase in the density of dislocation junctions, resulting in an increase in strain hardening visible in the load-displacement curve.