Are there phase transitions in liquid metallic alloys?

Temperature and time dependent structure of the molten Ni81P19 alloy by neutron diffraction

“…However, structural reorganization times in different kinds of liquids of the order hours and longer have earlier been reported [10 and refs therein]. For example, it was observed that 120 hours overheating at 700 degrees above the melting point was necessary to obtain a homogenous Bi30In70 alloy [17]. Furthermore, investigations by ultrasound techniques revealed that during a heating/cooling cycle up to temperature more than 900 o C above liquidus [41,42] and lasting for more than 20 hours the attenuation coefficient in molten eutectic PdSi decreases considerably, not only during heating but also during the subsequent cooling.…”

“…No obvious connection between the composition of these clusters and the crystalline stable phases found in the phase diagram seems to exist [16]. In this context, it should be mentioned that the presence of small amounts of oxides in many cases may have had a strong influence on a measured physical property and thus affected the results [17]. Accordingly, the preparation of the initial ingot is of outmost importance in this kind of measurements both in the liquid and in the solid state.…”

“…In some cases the anomalies have been interpreted as indications of the existence of liquid-liquid phase transitions, while in others they have been found to be related not only to the thermal history of the melt but also of the ingot [1][2][3][4][5]. A possible presence and disruption of oxides during heating of the melt has also been suggested to influence the experimental results [17]. In other studies it has been suggested that the existence of atomic clusters in molten alloys is of thermodynamic origin and that the status of the melt corresponds to specific metastable temperature-dependent states [7,18,19].…”

Perspective on Structural Evolution and Relations with Thermophysical Properties of Metallic Liquids

“…It was reported that an anomalous structure change with temperatures appears in Bi–In and In–Pb liquids by using electrical‐resistance measurements, which was ascribed to the onset of the LLT. However, Khalouk et al did the same measurements and found that the observed “anomalies” usually occur in the first scan, and would be attributed to the release of gas or vapor bubbles in the liquids at the first heating rather than a phase transition. Their work strongly suggests that it is quite necessary to combine several kinds of techniques, either experiments or simulations, to improve the credibility of observations on metallic liquids.…”

Thermal stability of cluster structure in BixSn1−xmolten alloys in vicinity of eutectic point

“…Most of the results were obtained by investigating the temperature changes of structure-sensitive properties [5,6]. However, other works indicate that the cause of changes in such property of melt as is attributed to the release of gas bubbles in the liquid alloy at the first heating, resulting from the decomposition of compounds like oxides or hydroxides of the metals, but not from a phase transition in the liquid metallic state [7].…”