| Abstract Scope |
Hydrogen embrittlement (HE) is a critical barrier to the development of ultrahigh-strength alloys, as traditional mitigation strategies based on structural defect engineering often compromise mechanical performance. To overcome this limitation, we introduce the concept of chemical affinity engineering, which utilizes alloying elements with intrinsically high affinity for hydrogen to control its diffusion and solubility without degrading strength. Density functional theory calculations were conducted to quantify hydrogen affinity energies, and cryogenic 3D atom probe tomography provided direct atomic-scale evidence of element–hydrogen interactions. Measurements of hydrogen solubility and diffusivity further confirmed the improved trapping behavior. Importantly, we demonstrate that integrating chemical affinity with structural affinity through ordered atomic structures creates a synergistic effect that enhances hydrogen trapping and significantly improves resistance to embrittlement. This approach establishes a new paradigm for designing ultrahigh-strength alloys with superior hydrogen tolerance, offering a promising direction for the development of advanced structural materials for extreme environments. |