10.1016/j.commatsci.2025.113858">
 

Atomistic Simulations of Short-range Ordering with Light Interstitials in Inconel Superalloys

Document Type

Article

Publication Date

5-2025

Abstract

This study employed hybrid Monte Carlo Molecular Dynamics simulations to investigate the short-range ordering behavior of Ni-based superalloys doped with boron or carbon. The simulations revealed that both boron and carbon dissociated from their host Ti atoms to achieve energetically favored ordering with Cr, Mo, and Nb. Boron clusters formed as B2, surrounded by Mo, Nb, and Cr, while carbon preferentially clustered with Cr to form a Cr23C6 local motif and with Nb to form Nb2C. Distinct preferences for interstitial sites were observed, with boron favoring tetrahedral sites and carbon occupying octahedral sites. In the presence of a vacancy, B2 shifted from the tetrahedral site to the vacancy, where it remained coordinated with Mo, Nb, and Cr. Similarly, carbon utilized vacancies to form Nb2C clusters. Excess energy calculations showed that B and C exhibited strong thermodynamic stability within their short-range ordered configurations. However, under Ti-rich conditions, C was more likely to segregate into TiC, despite preexisting ordering with Cr. This shift in stability suggests that increased Ti availability would alter carbide formation pathways, drawing C away from Cr-rich networks and promoting the development of TiC. Such redistribution may disrupt the continuity of Cr-based carbide networks, which play a critical role in stabilizing grain boundaries and impeding crack propagation. These effects further underscore the impact of interstitial-induced ordering on phase stability and microstructural evolution. This work provides an atomistic perspective on how boron- and carbon-induced ordering influences microstructure and mechanical properties. These findings highlight the critical role of interstitial-induced short-range ordering and demonstrate that this mechanism can be leveraged as a design principle to fine-tune alloy microstructures for specific engineering applications.

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The linked work is an Open Access manuscript of an article published by Elsevier. This manuscript is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. CC BY-NC-ND 4.0

The article's published version of record appears in volume 253 of Computational Materials Science as cited on this page. The full text of that VOR is available by subscription or purchase through the DOI link below.

Author note: Tyler Doležal is co-affiliated with the Massachusetts Institute of Technology

DOI

Version of Record: 10.1016/j.commatsci.2025.113858

Source Publication

Computational Materials Science (ISSN 0927-0256 | eISSN 1879-0801)

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