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MM: Fachverband Metall- und Materialphysik
MM 13: Topical Session: Defects of Defects
MM 13.4: Vortrag
Dienstag, 18. März 2025, 15:00–15:15, H10
A high-throughput ab initio segregation study of light elements at Ni grain boundaries and their effects on cohesion — •Han Lin Mai1, Jörg Neugebauer1, and Tilmann Hickel2 — 1Max-Planck-Institut for Nachhaltige Materialien GmbH, Dusseldorf, Germany — 2Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany
Segregation of alloying/tramp elements to grain boundaries (GBs) can drastically affect the properties of metallic alloys. We present a high-throughput density-functional theory-based study on the segregation of smaller elements, H, B, C, N, O, P, S, in a variety of FCC Ni GBs and their effects on cohesion. To support GB engineering efforts, we investigate the thermodynamics of segregation and calculate its effects on interface cohesion. These elements often play a significant role in engineering alloys, but their positioning at GBs is ambiguous and challenging to study. The study utilizes efficient and highly automated workflows using the integrated development environment pyiron. We discuss chemical and structural trends for segregation and cohesion at GBs for these elements. In order of segregation binding strength at GBs, the trend is approximately O > B, S > P > N = C = H. Elemental trends for maximum segregation binding strength across various GB models are largely consistent, enabling qualitative cross-element comparisons through small GB sets. However, conventional metrics, such as GB energy, are insufficient for predicting segregation strength or quantity for these elements.
Keywords: Grain boundary; Segregation; Grain boundary cohesion; Engineering alloys; Interfaces