Regensburg 2025 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 13: Topical Session: Defects of Defects

MM 13.5: Vortrag

Dienstag, 18. März 2025, 15:15–15:30, H10

Mechanistic Influence of Interstitial Solutes on Hydrogen Trapping at Σ5 GB in γ-Fe — •Poulami Chakraborty, Mauricio Rincon Bonilla, and Elena Akhmatskaya — Basque Centre for Applied Mathematics, Bilbao, Spain

The local variation of grain boundary atomic structures and chemistry caused by segregation of impurities influences the macroscopic properties of polycrystalline materials. Here, the effect of co-segregation of carbon and boron on hydrogen segregation at a Σ5 (210) [001] tilt grain boundary in γ-Fe phase is studied by density functional theory. The grain boundary structure predominantly features kite-like motifs, which are disrupted by atomic-scale defects. First-principles calculations indicate that carbon and boron exhibit the strongest segregation tendency. Their interaction with aluminum is notably repulsive, leading to aluminum depletion at the grain boundary. Subsequently, the effect of boron and carbon co-segregation is studied with the introduction of H at the GB. Our comprehensive investigation provides valuable insight in the interaction of interstitial impurities with substitutional solutes, which, strongly influences grain boundary composition and the properties of the interface.

Keywords: Hydrogen embrittlement; Density Functional Theory; steel; solute atoms; grain boundary