Impact of hydrogen distributions near screw dislocations on yield stress in α-Fe

P Kumar and MM Ludhwani and AK Kanjarla and I Adlakha, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 116, 178-189 (2025).

DOI: 10.1016/j.ijhydene.2025.02.435

The effect of solute hydrogen on dislocation-based plasticity in alpha- Fe was examined using a computational framework. To achieve this, various hydrogen configurations around the screw dislocation were identified, taking into account the glide direction, and spacing between hydrogen atoms. First, the variability in non- Schmid behavior during dislocation glide across different hydrogen arrangements was quantified through extensive atomistic simulations. The presence of hydrogen caused only a slight variation in lattice friction during dislocation glide across the different local hydrogen arrangements examined. Furthermore, there was a noticeable increase in planar dislocation glide in the presence of hydrogen. Subsequently, the variation in kink-pair activation enthalpy across different hydrogen configurations was quantified. The kink-pair activation enthalpy varied significantly depending on hydrogen configurations and spacing between hydrogen atoms along the dislocation line. The meso-scale yield stress across different hydrogen configurations was assessed using a dislocation-based crystal plasticity framework, leveraging atomistically quantified effects of hydrogen on dislocation glide.

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