Temperature-induced liquid state change and its effects on solidification of thermoelectric alloy Bi0.3Sb1.7Te3

Abstract

The behaviors of electrical resistivity vs temperature (ρ-T) of the molten p-type thermoelectric alloy Bi0.3Sb1.7Te3 (at.%) were explored in heating and cooling processes. An obvious hump appeared on the ρ-T curve from 932 ℃ to 1,020 ℃ at the heating process, while the curve became smooth in the following cooling, which suggests an irreversible temperature-induced liquid-liquid structure transition (TI-LLST) occurred in the liquid alloy. Based on this judgment, solidification experiments were carried out to find out the effects of the different liquid states. It was verified that, for the melt experiencing the presumed TI-LLST, both the nucleation and growth undercooling degrees were elevated and the solidification time was remarkably prolonged. On the other hand, the configuration of Bi0.3Sb1.7Te3 phase was refined, and its preferential orientation was weakened.

Keywords

• electrical resistivity; liquid-liquid structure transition; Bi0.3Sb1.7Te3; solidification