Document Type
Article
Publication Date
9-25-2026
Abstract
Grain boundary stabilization by light interstitials is central to the performance of Ni-based superalloys, yet the thermodynamic mechanisms governing their interactions with substitutional chemistry remain poorly resolved. Here, we use hybrid Monte Carlo molecular dynamics simulations to quantify how boron and carbon modify the thermodynamic, structural, and chemical ordering of grain boundaries in Ni-Cr alloys. By analyzing interfacial state variables, site-resolved segregation spectra, local chemical ordering, and structural evolution, we show that boron and carbon stabilize grain boundaries through complementary pathways. Carbon drives saturation-controlled stabilization by recruiting Cr and conditioning boundary chemistry, while suppressing temperature-driven structural transformations of the boundary. In contrast, boron stabilizes grain boundaries through a selective mechanism that lowers the interfacial grand potential via localized ordering while permitting gradual structural evolution. These effects arise from coupled interactions between interstitial segregation and Cr redistribution, which together regulate site accessibility, chemical competition, and the range of accessible interfacial states. This work provides a thermodynamic framework for grain boundary engineering and suggests design principles for leveraging interstitial-substitutional interactions in alloys.
Source Publication
npj Computational Materials (eISSN 2057-3960)
Recommended Citation
Doležal, T. D., Freitas, R., & Li, J. (2026). Complementary thermodynamic mechanisms of boron and carbon segregation at grain boundaries in nickel alloys. npj Computational Materials, 12(1), 321. https://doi.org/10.1038/s41524-026-02176-w
Included in
Atomic, Molecular and Optical Physics Commons, Metallurgy Commons, Thermodynamics Commons
Comments
© 2026 The Authors.
This article is published by Springer Nature, licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
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Tyler Doležal was co-affiliated with MIT at the time of this article's publication.