X-ray diffraction studies and Reverse Monte Carlo simulations of the liquid binary Fe–Si and Fe–Al alloys

Heat Flow in Earth's Core From Invariant Electrical Resistivity of Fe‐Si on the Melting Boundary to 9 GPa: Do Light Elements Matter?

“…Conversely, invariant ρ of liquid Fe‐4.5Si implies the existence of short‐range and perhaps medium‐range order liquid structures along the melting boundary, which impose a control mechanism on the behavior of ρ . This agrees well with the earlier studies, which used X‐ray diffraction and numerical simulations to demonstrate the existence of a local structures in liquid Fe‐Si, generally detected by the appearance of the shoulder in the first peak in the experimentally measured total structure factor S(Q; e.g., Roik et al, , and references therein). Thus, in order to understand the electrical resistivity of liquid Fe‐4.5Si along the melting boundary, and potential implications of its behavior and thermal conductivity on the dynamics of the Earth's OC, it is important to resolve the nature of those local structures in the liquid.…”

“…The increase in Si content and structural modification of Fe‐Si alloy affects the distribution of Fe 3d, Si 3s, and 3p orbitals. Roik et al () also demonstrated that the local atomic order in Fe‐Si melts exhibits similarity to that in the parent crystalline phase, which is characterized by a strong preference for heteroatomic nearest‐neighbor bonds. This agrees with the argument presented in Silber et al (), which suggests that the structure of solid parent phase has a strong influence on the behavior (and structure) of metallic liquid at high pressures in the vicinity of the melting point.…”

“…Indeed, the authors demonstrated the existence of polytetrahedral aggregates with a pentagonal symmetry, analogous to ISROs in liquid 3d transition metals (Roik et al, ). It is also important to note that liquid Fe‐Si alloys retains an overall Fe‐like structure if the Si content is below ~38 wt% (Roik et al, ).…”

“…Liquid Fe‐Si alloy is characterized by stronger interaction between Fe and Si atoms (Gu et al, ) than between Fe‐Fe or Si‐Si (Roik et al, ). Correspondingly, the calculated electronic structures of molten Fe‐Si alloys indicate that the interaction of Fe‐Si atoms originates from the hybridization of Fe 3d and Si 3p bands (e.g., Roik et al, , ). The Si atoms form bonding and antibonding states with the neighboring Fe atoms.…”

Effect of Silicon, Carbon, and Sulfur on Structure of Liquid Iron and Implications for Structure‐Property Relations in Liquid Iron‐Light Element Alloys

“…The data imply that the double‐peak feature in the second peak of S ( Q ) of liquid Fe‐28.9 at.% Si may be pronounced at high pressures. We found that the first peak position of S ( Q ) shifts more in liquid FeSi (~1.3% from ambient pressure, ~3.06 Å −1 by Roik et al, , to 3.7 GPa, 3.100 Å −1 in this study) than that of liquid Fe (~1.0% from ambient pressure, ~2.98 Å −1 by Roik et al, , to 3.7 GPa, 3.011 Å −1 in this study). The data imply that the double‐peak feature in the second peak of S ( Q ) of liquids Fe‐18.1 at.% Si and Fe‐28.9 at.% Si may become visible at high pressures possibly due to the different peak shifts between the S ( Q ) of liquid Fe and liquid FeSi.…”