The estimation of concentration fluctuations in liquid Ag–Si and Au–Si alloys

Abstract

The specific electrical resistivity was measured for liquid states of Ag-Si and Au-Si with deep eutectic points for which the "electron atom ratio" at the eutectic composition is 1.33 and 1.56 respectively. On lowering the temperature, the specific electrical resistivity deviates from the straight line, which was obtained by extrapolating its behavior in the high temperature to the low

Supercooling of Homogeneous Liquid Phase of Liquid Metals and Alloys —Poor Supercooling around the Eutectic Composition of Liquid Ni-Nb System—

“…In the present manuscript, at first, the validity of ESL technique for the study of supercooling of liquid metals was investigated by the survey of cooling curves of many liquid metals with high T m originally obtained in the experimental studies of many physical properties, such as density, surface tension, viscosity, thermal conductivity, and heat capacity. 11,12) In the next stage, this ESL technique was applied to the study of the supercooling for the homogeneous liquid phase of eutectic Ni-Nb system whose eutectic point is present at 40.5 at% Nb and 1448 K. 20) The particular feature of the result in the present study, a poor supercooling tendency around the eutectic composition, was discussed with the relation to the knowledge recently found, 17,[21][22][23][24] the existence of concentration fluctuations in the homogeneous liquid phase near the eutectic point.…”

“…According to the study of one of authors, 17,[21][22][23][24] the concentration fluctuations exist in the homogeneous liquid phase around the x e . The volume fraction of concentration fluctuation, 0 c , which was estimated from the electrical resistivity measurements for many liquid eutectic alloys, shows the maximum at the x e (''Ã'' shape).…”

“…It was concluded that such concentration fluctuations may correspond to microscopically pre-solidified domain prior to the phase transition from homogeneous liquid phase to two-solids one. 17,[21][22][23][24] This situation for the Ni-Nb liquids around the eutectic composition (Ni-40.5 at%Nb) can be described as the dispersion of solid-like spherical domains of Ni 3 Nb and Ni 6 Nb 7 20) in the homogeneous liquid phase even over the liquidus temperature. The volume fraction of these solid-like spherical domains, which may exists as concentration fluctuations, seems to be rather small, for example, 7% at the most.…”

“…Therefore, it has been implicitly considered that the liquid alloy of eutectic composition can be easily supercooled. However, one of authors 17) showed that the supercooling of liquid Bi-Sn and Pb-Sn alloys is smallest at the eutectic composition by referring to the previous DSC studies using the emulsions technique. 18,19) He also presented the interpretation that the supercooling of homogeneous liquids is suppressed around the eutectic composition due to the existence of concentration fluctuations which may originate from a pre-solidification phenomenon from liquid phase to two solids one.…”

NMR investigation of ionic motion in LiI-KI in the liquid state

“…The results suggest that the dynamics of ionic motion can be dependent on small change in the composition. They also found that similar phenomena in the electrical conductivity occur not only in the LiI-KI but also in many eutectic binary metallic mixtures [4].…”