Anisotropy and roughness of the solid-liquid interface of BCC Fe

Area of Science:

• Materials Science
• Computational Physics
• Solid-State Chemistry

Background:

• Understanding the anisotropic behavior of melting point and kinetic coefficients is crucial for materials processing.
• The solid-liquid interface properties significantly influence phase transition kinetics.

Purpose of the Study:

• To investigate the anisotropy of melting point (T m) and kinetic coefficient (μ) for body-centered cubic (BCC) iron.
• To elucidate the role of interfacial structural roughness in these anisotropic phenomena.
• To explore the asymmetry between melting and solidifying processes.

Main Methods:

• Molecular dynamics (MD) simulations using the Sutton-Chen potential.
• Characterization of atomic structure using average bond orientational order (ABOO) parameters and Voronoi polyhedron analysis.
• Calculation of interfacial roughness (R int) and area ratio (S/S 0).

Main Results:

• Anisotropy in T m was observed, decreasing from [100] to [110] and [111] orientations.
• Anisotropic kinetic coefficients (μ) were found for both solidifying and melting processes, with distinct directional dependencies.
• Interfacial roughness anisotropy ([100] > [111] > [110]) and asymmetry (melting rougher than solidifying) were quantified and correlated with μ anisotropy.

Conclusions:

• Interfacial roughness anisotropy and asymmetry directly influence the directional properties of the kinetic coefficient in BCC Fe.
• The findings provide a mechanistic explanation for the observed anisotropies in melting point and kinetic coefficient.
• MD simulations offer a powerful approach to study complex interfacial phenomena in materials.