Quantitative analysis based on the pair distribution function for understanding the anomalous liquid-structure change inIn20Sn80

Abstract

The temperature-induced anomalous liquid-structure change in melt In 20 Sn 80 observed by Zu et al. ͓Phys. Rev. Lett. 89, 125505 ͑2002͔͒ has been studied. The structure transition in In 20 Sn 80 is further confirmed by the presence of an exothermic peak in the differential-scanning-calorimetry ͑DSC͒ curve. From experimental data of pair distribution functions, we calculated the viscosity ͑͒ and the excess entropy ͑S͒ and found that there is a valley of viscosity in the -T curve and a valley of excess entropy in the S-T curve, which are consistent with the internal-friction ͑Q −1 ͒ peak in the Q −1 -T curve and the exothermic peak in the DSC curve, respectively. We decomposed S into two parts, S͑1͒ and S͑2͒, which are related to the total potential and the isothermal compressibility, respectively. The behaviors of S͑1͒ and S͑2͒ tell us that the atomic bonds vary twice and the microstructures transform twice in the temperature range from 300 to 900°C for liquid In 20 Sn 80 . The similar analysises of liquid In 80 Sn 20 and liquid Sn reveal that Sn plays a crucial role in the discontinuous structure change in liquid In 20 Sn 80 .

Temperature-Induced Liquid-Liquid Transition in Metallic Melts: A Brief Review on the New Physical Phenomenon

“…It should be pointed out that, although the abovementioned results of TI-LLST are limited in the investigations of ourselves, the similar phenomena have been observed by other groups with different resorts like viscosity [49,50], density and sound velocity methods [51,52], as well as computer simulations [53,54]. For example, by high-resolution measurements of the density, the heat capacity and the static structure factor, scientists out of Israel, USA and France found that a temperature-driven liquid-liquid structural transformation takes place quite above liquidus of Bi [55].…”

“…In China, with experimental procedures like X-ray diffraction, internal friction, viscosity, resistivity, etc. as well as theoretical simulation methods, several other groups in Institute of Solid State Physics of Chinese Academy of Sciences [54,60,61], Shandong University [49,62,63], Jinan University [64] and Fudan University [53] observed lots of TI-LLST phenomena in liquid metals and alloys.…”

Effect of Sn on reversibility of liquid–liquid transition in Bi–Sb–Sn alloys

“…In the past decade, considerable attention has been given to the research on the temperature or pressure dependence of liquid-liquid structure change in liquids, by different experimental methods and theoretical calculations [1][2][3][4][5][6][7][8][9][10]. The results of these studies reveal or indicate the existence of liquid-liquid transition in liquid metals or alloys.…”

Change in solidification behavior of Bi–Sb10 alloy after liquid structural transition

“…The temperature-induced liquid change implied that the liquid structure might change discontinuously, hundreds of degrees above the liquidus, as a function of temperature at constant pressure in melts. With X-ray diffraction method [7,15,16], internal friction technique [17][18][19], thermal analysis [17,20,21], viscosity measurement [22], electrical resistivity measurement [21,23,24] and ab initio molecular dynamics simulations [25], the phenomena have been observed in some binary alloys, such as In-Sn, In-Bi, Pb-Sn, Pb-Bi, Sn-Bi. Furthermore, the solidification microstructures Pb-Sn [26] and Al-Si [7] were changed greatly as liquid structural transition (LST) happened.…”