Experimental evidence of the transformation from microheterogeneous to microhomogeneous states in Ga–Sn melts

The electrical resistivities of liquid Ga–Sn system have been carefully measured as a function of temperature for different compositions employing direct-current four-probe method. It was well known that the electrical resistivity varies linearly with temperature for typical liquid metals. However, an abnormal change on the resistivity-temperature curve in the intermediate temperature region Ts–TeTs–Te (385–422 °C for Ga20Sn80 melt and 395–449 °C for liquid Ga10Sn90 melt, here TsTs and TeTe are denoted as the start-temperature and the end-temperature of the abnormal change) is observed in the initial Ga20Sn80 and Ga10Sn90 melts during first heating, but this abnormal behavior disappears during subsequent cooling as well as reheating process. This result indicates that in the initial Ga20Sn80 and Ga10Sn90 melts there may exist the microheterogeneities, during heating in the temperature range from TsTs to TeTe the irreversible structure transition possibly takes place from microheterogeneous melt to microhomogeneous melt. It suggests that the necessary overheating above liquidus up to TeTe is a guarantee of the molten alloy getting the microhomogeneous sate or the true solution and conserving it during cooling down to liquidus at any cooling rates.