Abstract
Ag-Pb-Te is an important system in thermoelectric applications. The liquidus projection is determined by using various ternary alloys. A ternary-eutectic reaction, L=PbTe+Te+Ag5Te3, was determined with a liquid composition of Ag-4.3at%Pb-62.6at%Te at 337℃, resulting in a nano-scale lamellar eutectic structure. The nanostructured Ag-Pb-Te eutectic alloy was further fabricated by unidirectionally solidifying using the Bridgeman method. Specially, the Bridgman-grown eutectic alloy exhibited a partially aligned lamellar microstructure, which consisted of Ag5Te3 and Te phases, with additional 200-600 nm size particles of PbTe. The self-assembled interfaces altered the thermal and electronic transport properties in the bulk Ag-Pb-Te eutectic alloy. Presumably due to phonon scattering from the nanoscale microstructure, a low thermal conductivity (κ=0.3W/mK) was achieved of the eutectic alloy, leading to a zT peak of 0.41 at 400K.