Liquid-liquid phase transition: is it possible in Fe melts?

Abstract

Abstract. In present work we present the results of ab initio molecular dynamics simulation of magnetic properties of liquid iron. This simulation has been performed using the computer package SIESTA for temperature range: 1833, 1873, 1923, 2023 K. Our focus is on possibility of magnetic liquid-liquid phase transition in iron melts.

Structural changes in liquid Fe and Fe–B alloy on cooling

“…The thermal expansion of the glassy alloys and melts upon heating or cooling was studied by Synchrotron X-ray radiation diffraction for Fe 40 Ni 40 P 14 B 6 [22], Pd 40 Cu 30 Ni 10 P 20 [23], Zr 55 Cu 30 Ni 5 Al 10 [24,25], various La-based [26,27], Cu-Zr alloys [28][29][30], Cu 55 Hf 25 Ti 15 Pd 5 and Cu 55 Zr 30 Ti 10 Ni 5 [31] compositions. Structural changes in the Pd 42.5 Cu 30 Ni 7.5 P 20 melt upon vitrification were studied in-situ [32] and intensification of the covalent bonding between P on one hand and Ni and Cu on the other one was observed close to the glass transition region [33] which was found to be responsible for fragility of this liquid.…”

“…There were suggestions that liquid-liquid phase transitions occur in liquid P [36], Sn-Bi melt [37], alumina [38] and C [39], and also, may take place in Fe [40], Fe-Cr [41] and Fe-B alloys [42]. There are also reasons to consider that supercooled liquid silicon undergoes a first-order phase transition, from a fragile, dense liquid to a strong, low-density liquid with nearly tetrahedral local coordination at 1060 K [43].…”

New potentials for multiscale simulations of liquid metals

“…As local magnetic moments on iron atoms exist also above Curie temperature, we employed spin polarization for all AIMD runs. Previously we performed the study of influence of local magnetic moments on the structure of liquid iron [7] and found that it is necessary to properly account for magnetic effects to get the structure RDF close to experimental. The same conclusion was made by Ganesh and Widom in [8].…”