Study on Structural Variation of Sn–20% Pb Alloy Melt Subjected to Ultrasonic Vibration: An Electrical Characterization.

The electrical resistance variation of the Sn–20% Pb alloy melt subjected to ultrasonic vibration was investigated using four-electrode method. The modified energy band theory and cavitation dynamics simulation were employed to explain the experimental results. The ultrasonic vibration in the liquid disrupted the melt structure and enhanced the forced vibration of the atoms, resulting in a reversible liquid–liquid structural transformation and a sharp decrease in electrical resistance. The evolution of the optical microstructure suggested that the ultrasonic-induced refining and homogenizing effects of short-range ordered structures were time-sensitive. The numerical simulation of cavitation dynamics indicated that the structural variation was the substantial root for the electrical resistance change by ultrasonic irradiation, and the high energy required for the reversible structural variation was provided by the collapsing cavities. [ABSTRACT FROM AUTHOR]