Enhanced Hydrogen Embrittlement Resistance via Cr Segregation in Nanocrystalline Fe–Cr Alloys

Hydrogen is a clean fuel with numerous sources, yet the hydrogen industry is plagued by hydrogen embrittlement (HE) issues during the storage, transportation, and usage of hydrogen gas. HE can compromise material performance during service, leading to significant safety hazards and economic losses. In the current work, the influence of element Cr on the HE resistance of nanocrystalline Fe–Cr alloys under different hydrogen concentrations and strain rates was evaluated. With hybrid Monte Carlo (MC) and molecular dynamics (MD) simulations, it was found that Cr atoms were segregated at grain boundaries (GB) and inhibited the GB decohesion. Correspondingly, Cr segregation improved the strength and plasticity of the nanocrystalline Fe–Cr alloys, especially the HE resistance. Moreover, the Cr segregation reduced the diffusion coefficient of hydrogen and inhibited hydrogen-induced cracking. This work provided new insight into the development of iron-based alloys with high HE resistance in the future.