Exploration Of Temperature-induced Liquid-liquid Structure Transition Of PbSnBi Ternary Alloy

Liquid-liquid structural change has become a common concern in liquid physics these years, which enriches the phenomenology in liquid physics and shed light on the structure and property of liquid materials. However, the essence of this phenomenon is still seldom known.In order to study the adaptability of temperature-induced discontinuous liquid structural change, we carry on an investigation of the temperature dependence of electrical resistivity (p-T) and structure analysis of liquid PbSnBi alloy. As follows, it is most content in this paper:First, we carry on a research of electrical resistivity characteristic with temperature, and find the electrical resistivity of alloy have abnormal change with temperature, compared to the electrical resistivity of pure Pb, Sn, Bi, by the four-electrode contact method. This change shows that there are temperature-induced liquid-liquid discontinuous transitions in the liquid alloy.Second, the DSC is used to verify the occurrence of the alloy liquid-liquid structure change further, the endothermic peak on the DSC curve also proved the existence of liquid —liquid structure change during the period of heating continuously. The reason of that change is the previous bonds and local short-range orders which are derived form solid state are broken to form new bonds or dissolve to make the high temperature liquid more disorder. At the same, the credibility of four-electrode contact method is also proved.Third, it is also found that there are liquid-liquid transitions during cooling process, but we find it is only reversibility for the second or later hot circulation. The concrete reason of this kind of phenomenon may be because the interactions of the special atoms in these composition organizations which make its property special, so the structure changes remain exist in the cooling process.Fourth, the solidification behavior and microstructure of PbSnBi alloy are investigated. It is found that solidification undercooling degree increases greatly after liquid structure change and the solidification structure becomes finer evidently. The result shows that temperature-induced discontinuous liquid structural change affects the solidification behavior and microstructure remarkably.