In situ study on the orientation and strain-rate correlation mechanism of hydrogen embrittlement behavior of ferrite under shear stress

This study investigates the effects of orientation and strain rate on the hydrogen-enhanced localized plasticity mechanism during shear deformation of interstitial free steel. The stress-orientation correlation of hydrogen embrittlement is related to atomic-scale mechanisms, as evidenced through in situ electron backscatter diffraction, slow-strain-rate shear testing, electron microscopic characterization, and molecular dynamics simulations. The dislocation density increment after hydrogen charging was 59.25% higher along the [100] crystallographic zone axis than along the [11‾1‾] crystallographic zone axis, which is mainly attributed to the combined effect of strain-induced transport and interstitial diffusion of hydrogen atoms. The strain rate correlation of hydrogen embrittlement is also affected by the interstitial diffusion during the strain-induced transport of H. Interstitial diffused hydrogen induce dislocation forest emissions that promote local plasticity, which ultimately leads to the orientation and strain rate correlation of hydrogen embrittlement.