Elastic modulus, biaxial fracture strength, electrical and thermal transport properties of thermally fatigued hot pressed LAST and LASTT thermoelectric materials

A. Q. Morrison, E. D. Case*, F. Ren, A. J. Baumann, D. C. Kleinow, J. E. Ni, T. P. Hogan, J. D'Angelo, N. A. Matchanov, T. J. Hendricks, N. K. Karri, C. Cauchy, J. Barnard, M. G. Kanatzidis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Harvesting of waste heat may lead to macrocrack and/or microcrack damage accumulation in thermoelectrics. No studies in the open literature address the thermal fatigue of any thermoelectric material. This study characterizes the thermal fatigue behavior for two PbTe-based thermoelectric materials, n-type LAST (lead-antimony-silver-tellurium) and p-type LASTT (lead-antimony-silver- tellurium-tin). The mechanical properties (fracture strength, elastic moduli) were evaluated for up to 200 thermal fatigue cycles. In addition, the electrical and thermal transport properties were evaluated for n- and p-type specimens for thermal cycling. The elastic moduli were relatively insensitive to thermal fatigue treatment. The fracture strength, σ f, of the thermally fatigued LASTT specimens was in a band of from 25 to 40 MPa while σ f of the thermally fatigued LAST ranged from 15 to 38 MPa. The thermopower and electrical conductivity of LASTT samples showed small deviations from the low temperature trend near 600 K and the data repeated well after the first temperature cycle for all samples. For the n-type LAST samples, the electrical conductivity and thermopower showed larger deviations from the low temperature trend near 500 K with some samples requiring several temperature cycles before showing repeatability in the data, suggesting a possible secondary phase in the samples.

Original languageEnglish (US)
Pages (from-to)973-987
Number of pages15
JournalMaterials Chemistry and Physics
Volume134
Issue number2-3
DOIs
StatePublished - Jun 15 2012

Keywords

  • Electrical conductivity
  • Fracture strength
  • Thermal fatigue
  • Thermoelectrics
  • Thermopower
  • Young's modulus

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics

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