Effect of atomic scale plasticity on hydrogen diffusion in iron; Quantum mechanically informed and on-the-fly kinetic Monte Carlo simulations

Ramasubramaniam, A.*; Itakura, Mitsuhiro  ; Ortiz, M.*; Carter, E. A.*

We present an off-lattice, on-the-fly kinetic Monte Carlo (KMC) model for simulating stress-assisted diffusion and trapping of hydrogen by crystalline defects in iron, which is supplemented by high-accuracy density functional theory calculations. Effective diffusivities obtained from KMC simulations are found to be in good agreement with theory. Our model provides an avenue for simulating the interaction of hydrogen with cracks, dislocations, grain boundaries, and other lattice defects, over extended time scales, albeit at atomistic length scales.