Hydrogen embrittlement in metals is strongly governed by hydrogen diffusion and trapping, yet predicting these effects in polycrystalline systems remains challenging. This work introduces a multiscale modeling framework that links atomistic energetics to continuum-scale transport. Migration barriers for bulk and grain-boundary environments, obtained from first-principles calculations, are used in kinetic Monte Carlo simulations to compute anisotropic effective diffusivities. These diffusivities are then incorporated into finite element models of polycrystalline microstructures, explicitly accounting for grain-boundary character and connectivity. The approach captures both fast-path and trapping effects without relying on empirical parameters and reproduces experimental trends for nickel, including the dependence of effective diffusivity on grain size and boundary type. This methodology provides a physically grounded route for predicting hydrogen transport in engineering alloys and can be extended to other materials and defect types.
@article{arxiv.2601.05917,
title = {First-principles study of hydrogen diffusion in polycrystalline Nickel},
author = {Bhanuj Jain and Alaa Olleak and Junyan He and Adarsh Chaurasia and Davide Di Stefano},
journal= {arXiv preprint arXiv:2601.05917},
year = {2026}
}