Effect of liquid-liquid transition on solidification and wettability of Sn-0.7Cu-xBi solder

Abstract

The electrical resistivity-temperature curve (ρ-T ) of Sn-0.7Cu-xBi (wt.%) melts was measured, and anomalous changes were observed on the ρ-T curve at the temperature far above the corresponding liquidus. The results reveal that the melts have experienced a temperatureinduced liquid-liquid transition (LLT), and the transition is reversible after the first cycle heating. Based on the result of LLT, solidification experiments and spreadability testing were carried out on the Sn-0.7Cu-xBi alloy to investigate the effect of LLT on the solidification and wettability. The results show that the microstructure was refined, and the wettability was improved when the solder samples solidified from the melt experienced LLT.K e y w o r d s : Sn-0.7Cu-xBi solders, liquid-liquid transition, solidification, wettability

Kinematic Viscosity and Electrical Resistivity of a Multicomponent Melt due to Liquid–Liquid Structure Transition

“…A change in the liquid structure is associated with a liquid-liquid structure transition (LLST) [3,4], which is accompanied by a change in the thermophysical properties of the melt [5]. Viscosity and electrical resistivity are most sensitive to structural changes in the melt [6,7]. In [7,8], the electrical resistivity of tin solders melts was investigated during three successive heating-cooling cycles.…”

“…Viscosity and electrical resistivity are most sensitive to structural changes in the melt [6,7]. In [7,8], the electrical resistivity of tin solders melts was investigated during three successive heating-cooling cycles. Thermal cycling, that is, repeating the heating-cooling cycle many times, makes it possible to establish whether the LLST is reversible.…”