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Updated: Jun 3, 2026

Determining the Mechanical Strength of Ultra-Fine-Grained Metals
Published on: November 22, 2021
First-principles study of He effects in a bcc Fe grain boundary: site preference, segregation and theoretical tensile
Lei Zhang1, Xiaolin Shu, Shuo Jin
1Department of Physics, and Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education), Beijing University of Aeronautics and Astronautics, Beijing, People's Republic of China.
Abstract:
We perform a first-principles calculation to investigate the effects of He in an Fe Σ5(310)/[001] grain boundary (GB) with the SIESTA code, for which the reliability of the pseudopotential and the basis set are systematically tested. We calculate the formation and segregation energies for different substitutional and interstitial cases in order to determine the site preference and the segregation properties of He in the Fe GB. It is demonstrated that the He segregation either breaks (substitution) or weakens (interstitial) the surrounding interfacial Fe-Fe bonds, leading to the GB tensile strength reduction.
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