Different trends in surface atomic preference during the heating and melting process of Fe-Ni-Cr-Co-Cu high-entropy alloy nanoparticles: a molecular dynamics simulation study

WC Shi and YP Jia, JOURNAL OF NANOPARTICLE RESEARCH, 27, 284 (2025).

DOI: 10.1007/s11051-025-06474-0

The melting behavior of high-entropy alloy nanoparticles (HEA-NPs) is a critical determinant of the microstructure and properties of alloys fabricated via melting-sintering processes. A fundamental understanding of this behavior is therefore essential for advancing the development of novel HEA materials. In this study, molecular dynamics simulations were employed to investigate the different trends in surface atomic preferences during the heating and melting processes of Fe-Ni-Cr-Co-Cu HEAs-NPs under various sizes and melting rates. The results indicate that the surface structure of the NPs remains stable before reaching the melting point; once the melting point is attained, the surface melts rapidly first, followed by the overall melting of the NP. During the heating process, Cu and Cr exhibit surface segregation phenomena before melting, and this trend remains stable, unaffected by NP size and heating rate. After reaching the melting point, Cu segregation at the surface intensifies, while Cr no longer segregates to the surface, and the trend of Fe segregation at the surface decreases as the heating rate increases. Furthermore, we conducted an in-depth analysis of the causes of these different trends in surface atomic preferences during the heating and melting process from the perspectives of average atomic potential energy. Atomic potential energy can intuitively display the enthalpy evolution and atomic scale thermodynamic evolution trends in non-equilibrium processes in our work. Our research reveals the melting characteristics and surface atomic preference trends of Fe Ni Cr Co Cu HEA-NPs, providing valuable insights for the application of HEA-NPs in sintered materials.

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