The solid–liquid interface free energy of Al: A comparison between molecular dynamics calculations and experimental measurements

In this study, molecular dynamics (MD) simulations were performed to calculate the solid–liquid interface (SLI) free energy and its anisotropy of Al using the capillary fluctuation method (CFM) and a third generation of charge-optimized many body (COMB3) potential. The two thresholds (ϕ_min, ϕ_max) used to define interfacial atoms and the thickness of the bin (Δ) used to define the SLI profile significantly affect the obtained stiffness. The influence of the three parameters is discussed and optimal values for these parameters are also given. The magnitude of the SLI free energy of pure Al at the melting point is found to be 172.67 ± 22.90 mJ/m² through a detailed discussion of available experimental results. This result is compared with the SLI free energies of Al calculated from the COMB3 potential, two embedded-atom method (EAM) potentials and a modified embedded-atom method (MEAM) potential. It is found that both the COMB3 potential and the MEAM potential give predictions of the SLI free energy very close to the true value, while the EAM potentials underestimate this value quite a lot.