Temperature dependence of liquid structures in In-Sn20: diffraction experimental evidence

In our prior studies, it was suggested, by the internal friction and thermal analysis experimental results, that a temperature-induced discontinuous liquid-liquid structure change might occur in some alloys such as Pb-Sn, Pb-Bi and In-Sn. By means of X-ray diffraction, in the present study, we observed directly the occurrence of such a structure change in the melt In-Sn20. During the change, a sudden drop happened for both the nearest neighbor distance and the coordination number, and the size of short-range orders decreased abruptly. The calculated results of the pair correlation entropy showed that the ordering degree of the melt altered obviously and revealed the discontinuous feature of the change. Thus it presents a challenge to our conventional picture of liquids as entities with continuously varying averaged structure