Deformation behavior and mechanism of p-type (Bi,Sb)2Te3 alloy during three-point bending test at room temperature

In order to improve the machining process to engineer microstructure and defect types so as to further enhance the thermoelectric properties, it is desirable to understand the deformation behavior and mechanism of polycrystalline Bi2Te3 alloys. This work investigated the deformation behavior and mechanism of (Bi,Sb)2Te3 alloy during three-point bending tests using electron backscatter diffraction (EBSD). Results indicated that both dislocation slip and twinning occurred during the bending tests. The twins with the twin orientation relationship of (0001)M//(0001)T were observed. In addition, the nano-grains extruded the coarse grains in such a way that coarse grains assumed an orientation vulnerable to fracture along the basal planes. Slip trace analysis revealed that 13<112¯0> dislocation slipping on basal planes broke the Van der Waals bonds between the basal planes which eventually led grains to fracture. Additionally, a novel model was introduced that first incorporated the bending moment diagram in order to deduce the deformation process.