Investigation of microheterogeneities in Ga-Pb melts by acoustic methods

The pulse phase method of measuring the ultrasound velocity Vs was used for investigation of the microheterogeneity of hypermonotectic Ga-Pb melts. The method allows measuring Vs at various distances from the bottom of the crucible. An anomalous variation of the ultrasound velocity along the vertical axis of the crucible both in two-phase and the one-phase regions of the phase diagram was observed. The effect disappears irreversibly after a sufficient overheating the melt above the phase separation line. The phenomenon is linked with a metastable microheterogeneity of investigated melts. An experimental method to detect microdroplets inside the liquid solution is proposed and their volume fraction and mean size are calculated.