Surface segregation of liquid metal plasma-facing component alloys: A ReaxFF investigation

Fuente: arXiv
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Main Authors: Munshi, Md Adnan Mahathir, Shuvo, Abdul Aziz, Kotschenreuther, Mike, van Duin, Adri C. T., Ramos-Alvarado, Bladimir
Format: Preprint
Published: 2026
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author Munshi, Md Adnan Mahathir
Shuvo, Abdul Aziz
Kotschenreuther, Mike
van Duin, Adri C. T.
Ramos-Alvarado, Bladimir
author_facet Munshi, Md Adnan Mahathir
Shuvo, Abdul Aziz
Kotschenreuther, Mike
van Duin, Adri C. T.
Ramos-Alvarado, Bladimir
contents Engineering liquid metal alloys offers a transformative pathway for plasma-facing components (PFC) by enabling chemically tailored surfaces that can simultaneously optimize plasma-material interactions, reduce divertor heat flux, and enhance core plasma confinement, thereby advancing the commercial viability of nuclear fusion power plants. This study, employing an atomistic simulation framework, provides direct evidence that incorporating non-metal surface-active agents (such as O and H, or their combination) enables strong surface segregation. This capability makes tin-aluminum (Sn-Al) and tin-lithium (Sn-Li) alloys, with suitable compositions, good candidates for PFC applications. Specifically, the presence of low-Z solutes (Li, Al) leads to preferential surface enrichment, which imparts low-Z sputtering characteristics, while the Sn solvent maintains thermophysical stability. To systematically examine this behavior, we first optimized ReaxFF parameter sets for Sn-Al, Sn-Al-O, Sn-Li, Sn-Li-O, Sn-Li-H, and Sn-Li-O-H systems. We validated them using formation energies and elastic constants. We then employed reactive molecular dynamics simulations to resolve the coupled effects of surface segregation and impurity-driven chemistry at fusion-relevant temperatures. We also introduced an overlap-based segregation index that captures interfacial compositional separation directly from atomistic density distributions. This metric reveals a clear hierarchy of segregation regimes across all systems and presents a unified view of segregation across all observations reported herein. Together, these findings establish a mechanistic link between non-metal chemistry and interfacial structure, providing a predictive framework for designing self-adaptive, low-sputtering liquid metal alloys for fusion applications.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01863
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Surface segregation of liquid metal plasma-facing component alloys: A ReaxFF investigation
Munshi, Md Adnan Mahathir
Shuvo, Abdul Aziz
Kotschenreuther, Mike
van Duin, Adri C. T.
Ramos-Alvarado, Bladimir
Materials Science
Engineering liquid metal alloys offers a transformative pathway for plasma-facing components (PFC) by enabling chemically tailored surfaces that can simultaneously optimize plasma-material interactions, reduce divertor heat flux, and enhance core plasma confinement, thereby advancing the commercial viability of nuclear fusion power plants. This study, employing an atomistic simulation framework, provides direct evidence that incorporating non-metal surface-active agents (such as O and H, or their combination) enables strong surface segregation. This capability makes tin-aluminum (Sn-Al) and tin-lithium (Sn-Li) alloys, with suitable compositions, good candidates for PFC applications. Specifically, the presence of low-Z solutes (Li, Al) leads to preferential surface enrichment, which imparts low-Z sputtering characteristics, while the Sn solvent maintains thermophysical stability. To systematically examine this behavior, we first optimized ReaxFF parameter sets for Sn-Al, Sn-Al-O, Sn-Li, Sn-Li-O, Sn-Li-H, and Sn-Li-O-H systems. We validated them using formation energies and elastic constants. We then employed reactive molecular dynamics simulations to resolve the coupled effects of surface segregation and impurity-driven chemistry at fusion-relevant temperatures. We also introduced an overlap-based segregation index that captures interfacial compositional separation directly from atomistic density distributions. This metric reveals a clear hierarchy of segregation regimes across all systems and presents a unified view of segregation across all observations reported herein. Together, these findings establish a mechanistic link between non-metal chemistry and interfacial structure, providing a predictive framework for designing self-adaptive, low-sputtering liquid metal alloys for fusion applications.
title Surface segregation of liquid metal plasma-facing component alloys: A ReaxFF investigation
topic Materials Science
url https://arxiv.org/abs/2605.01863