Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published February 2007 | public
Journal Article

Solidification microstructure of alloys in the pseudo-binary PbTe-Sb_2Te_3 system

Abstract

The effects of composition and cooling rate on the microstructures of alloys in the pseudo-binary PbTe–Sb_2Te_3 system were investigated as a first step towards the design of nanostructured materials with enhanced thermoelectric properties. Liquid alloys of three different compositions were cooled in three distinct ways: water quenching, air cooling and furnace cooling. The resultant structures and phases were examined by electron microscopy, electron microprobe chemical analysis and electron backscatter diffraction. The compound Pb_2Sb_6Te_(11) precipitated as a metastable phase (in conjunction with PbTe and/or Sb_2Te_3) under all conditions. Furthermore, whereas PbTe exhibited dendritic morphology, Sb_2Te_3 and Pb_2Sb_6Te_(11) crystallized as lamellar platelets with preferred (0 0 1) orientation. The range of cooling rates was from ∼1 to 26 K/s, while the characteristic microstructural feature size ranged from 10 to 35 μm for dendrites, and from 15 to 50 μm for lamella. The prospects for achieving nanoscale structure are discussed.

Additional Information

Copyright © 2006 Acta Materialia Inc. Received 21 April 2006. Revised 14 September 2006. Accepted 21 September 2006. Available online 15 December 2006. T.I. is supported by NSF (Contract No. DMR-0080065) through Caltech's Center for the Science and Engineering of Materials (CSEM) and the Office of Naval Research. Portions of this work were carried out at the Jet Propulsion Laboratory/California Institute of Technology, with the help of Charles C. Hays; H.A. was supported by the JPLUS program at JPL/Caltech. We gratefully acknowledge the assistance of Dr. Chi Ma of Caltech for assistance with acquisition of electron microscope and electron backscattering diffraction images. We greatly appreciate C.M. Garland for advice in sample preparation for electron backscattering diffraction experiments and Meredith Russell for preliminary investigations.

Additional details

Created:
August 22, 2023
Modified:
October 25, 2023