Dependence of Solidification for Bi 2 Te 3−x Se x Alloys on Their Liquid States

摘要: The resistivity versus temperature (ρ-T) behaviours of liquid n-type Bi2Te3−x Se x (x = 0.3, 0.45 and 0.6) alloys are explored up to 1050 °C. A clear hump is observed on all ρ-T curves the three studied melts during heating process, which suggests that a temperature-induced liquid-liquid structural transition takes place in melts. Based this information, solidification microstructures with different states investigated. samples experienced show nucleation growth undercooling degrees conspicuously enlarged time shortened. As result, solidified lamellae refined homogenized, prevalence low-angle grain boundaries between these increased, Vicker Hardness enhanced. Atom probe tomography analyses prove there no segregation or nanoprecipitation within grains, but Te-rich eutectic structure evolution composition near Te-matrix phase boundary investigated sample transition. Our work implies Bi2Te3−xSex strongly related their parent states, providing an alternative approach tailor thermoelectric mechanical properties even when only simple process performed.