Different solidification behaviours of Bi-10wt%te alloy induced by liquid structural change

摘要

By means of DC four-probe technique, the temperature dependence of the electrical resistivity (-T) of liquid Bi-10wt%Te alloy has been measured. Two abnormal changes on the -T curve within the temperature ranges of 497-550 C and 639-708 C suggested that two irreversible liquid-liquid structural changes (LLSC) occurred. To explore the effects of the LLSC on the solidification behaviour of the alloy, solidification experiments were carried out. The results show that after experiencing LLSC, there will be enlarged undercooling, much finer microstructures and larger quality of Bi_2Te phase. Moreover, the morphology of solidified Bi_2Te is changed from dendrite to equiaxed.