The Reversibility Of Liquid-liquid Structural Change Of Pb-Sn,In-Sn And Pb-Bi Alloys

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, whether this phenomenon is reversible is still unknown.In this paper , we prove that the measurement of electrical resistivity is effective in investigating structural change in liquid alloys. Based on it, we carry on investigation of the temperature dependence of electrical resistivity (ρ-T) and structure analysis of liquid Pb-Sn,In-Sn and Pb-Bi alloys in the process of several-cycle heating and cooling, in order to research the reversibility of liquid-liquid structural change. The results are as follows:First, we find that there are two kinds of transitions in Pb-Sn and In-Sn alloys. One is the irreversible transition in the first heating process. The other is the reversible transition after the first heating process. But only the irreversible transition occurs in Pb-Bi alloy.Second, comparing with theρ-T curve of liquid Sn , the reversible transition in A-Sn alloy is caused by the fact that Sn-Sn covalent bonds are broken and rebuilt with temperature elevating and falling.Third, the electrical resistivity of liquid InSn49.1,InSn70 and (Pb_43.9Bi_56.1)₂₀Sn₈₀ alloy are measured. Results show that anomalous changes occur at the temperature near melting point, and this change is reversible.Fourth, the phenomena relating to the reversibility of liquid-liquid structural change are various. Wether the change is reversible and the temperature range of the structural change are different with different compositions.Fifth, we analyze the phenomena of liquid-liquid structural change by electron theory of alloys.In conclusion, the results of this paper are not only useful to study the law of liquid-liquid structural change, but also to improve the method of materials processing.