Wetting behavior of Cu droplets on Fe Surfaces: Insights from molecular dynamics simulations

• Published in: Computational materials science Vol. 242; p. 113106
• Main Authors: Cheng, Luyao, Mei, Haojie, Chen, Liang, Wang, Feifei, Wu, Boqiang, Yang, Yang, Li, Jinfu, Kong, Lingti
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2024
• Subjects: Molecular dynamics simulations; Solid-liquid interface; Spreading kinetics; Wetting anisotropy; Wetting anisotropy; Solid-liquid interface; Molecular dynamics simulations; Spreading kinetics
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2024.113106

[Display omitted] •Cu droplets demonstrate superior wettability and the fastest spreading on Fe(111) surfaces, while exhibiting the poorest wettability and lowest spreading rate on Fe(001) surfaces.•The wetting process comprises a fast-spreading regime driven by inertia and a slow-spreading regime governed by surface tension, with dissolution reactions further enhancing the wetting kinetics.•On Fe(001) surfaces, the spreading of precursor films can be described by the molecular-kinetic model, while the main bodies of the droplets follow the hydrodynamic model.•On Fe(110) and (111) surfaces, the main limiting factor for spreading is the friction dissipation between the main bodies of the droplets and the precursor films, in line with the molecular-kinetic model. Molecular dynamics simulations were performed to investigate the wetting behavior of Cu droplets on three distinct Fe surfaces: Fe(001), Fe(110), and Fe(111). The results reveal that Cu droplets exhibit a relatively stable layering order near the solid–liquid interface on all Fe surfaces while displaying different three-phase contact line structures. Influenced by the substrate surface structure and the extent of interfacial reactions, Cu droplets demonstrate superior wettability and the fastest spreading on Fe(111) surfaces, while exhibiting the poorest wettability and lowest spreading rate on Fe(001) surfaces. The spreading of Cu droplets on all Fe surfaces exhibits a similar driving mechanism, while is applicable to different spreading kinetic models emphasizing varying dissipation channels. The wetting process comprises a fast-spreading regime driven by inertia and a slow-spreading regime governed by surface tension, with dissolution reactions further enhancing the wetting kinetics. On Fe(001) surfaces, the spreading of precursor films can be well described by the molecular-kinetic model, while the primary dissipation mechanism for the main bodies of the droplets is the viscous dissipation within liquids, consistent with the hydrodynamic model. Conversely, on Fe(110) and (111) surfaces, the main limiting factor for spreading is the friction dissipation between the main bodies of the droplets and the precursor films, in line with the molecular-kinetic model. These findings offer new insights into the wetting phenomena of metal/metal systems, particularly the liquid metal embrittlement associated with Cu(l)/Fe(s) wetting.