Quantifying nonlinear hydrogen–dislocation interactions in face-centered-cubic metals

A three-dimensional nonlinear hydrogen-dislocation interaction framework for FCC metals is developed that captures the strong near-core coupling neglected by linear models. The model predicts localized hydrogen-induced repulsive stresses that act as a barrier to dislocation-glide, and dislocation source-activation activation depends on the competition between line tension and hydrogen-induced repulsive stresses. Hydrogen has a minimal effect on activation of short dislocations and a dominant role for longer dislocations. This transition depends on dislocation core radius, length, and equilibrium hydrogen-concentration. Finally, conventional hydrogen-interaction free-energy models are shown to predict nonphysical hydride-formation, motivating the need for concentration-dependent, physics-informed descriptions of hydrogen in metals.Impact statementWe present a 3D nonlinear framework for hydrogen–dislocation interactions that captures sharp near-core repulsive H-induced stresses, quantifies their impact on dislocation activity, and resolves key limitations of existing models.