Texture development during deformation processing of the n-type bismuth telluride alloy Bi2Se0.3Te2.7

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 588; pp. 376 - 387
• Main Authors: Srinivasan, Raghavan, McReynolds, Kevin, Gothard, Nicholas W., Spowart, Jonathan E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 20.12.2013; Elsevier
• Subjects: Applied sciences; Bismuth telluride; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; Cross-disciplinary physics: materials science; rheology; Crystallographic texture; Deformation structures; EBSD; Electronic transport in condensed matter; Exact sciences and technology; Forming; Materials science; Metals. Metallurgy; Other heat and thermomechanical treatments; Physics; Production techniques; Rolling; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Thermoelectric and thermomagnetic effects; Treatment of materials and its effects on microstructure and properties; Deformation structures; Crystallographic texture; Bismuth telluride; EBSD; Hot deformation; Transport properties; Material processing; Rolling; Sandwich structures; Fibers; Thermoelectric properties; Hexagonal lattices; Rolling texture; Trigonal lattices; Thermoelectric power; Plane strain; Bismuth; Extrusion; Transport processes; Magnesium; Figure of merit; Crystal structure
• DOI: 10.1016/j.msea.2013.09.044
• ISSN: 0921-5093

The n-type bismuth telluride alloy Bi2Se0.3Te2.7 was subject to hot deformation under several deformation conditions, such as extrusion, sandwich rolling, and plane strain compression. The resulting crystallographic texture is found to depend on the initial texture, strain imposed during deformation, the type of deformation, and proximity to the die surface. Bismuth telluride has a trigonal crystal structure, based on a hexagonal lattice with a c/a ratio of 6.96. During rolling, the material develops a rolling fiber texture in which the [0001] is oriented perpendicular to the rolling plane and the 〈112¯0〉 directions are randomly oriented in the plane of rolling. This texture is typically observed in a low c/a ratio material like magnesium. Measurement of the thermoelectric transport properties indicate that n-type bismuth telluride with a rolling fiber texture can have a non-dimensional figure of merit ZT of almost 1 at room temperature.