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 language | English (US) |
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Pages (from-to) | 973-987 |
Number of pages | 15 |
Journal | Materials Chemistry and Physics |
Volume | 134 |
Issue number | 2-3 |
DOIs | |
State | Published - Jun 15 2012 |
Funding
The authors acknowledge funding from Strategic Environmental Research and Development Program provided by a subcontract through Pacific Northwest National Laboratory . The authors also acknowledge the Defense University Research Instrumentation Program (DURIP) Grant No. N00014-09-1-0785 , Office of Naval Research , which provided funding for the purchase of the Resonant Ultrasound Spectroscopy apparatus utilized in this research.
Keywords
- Electrical conductivity
- Fracture strength
- Thermal fatigue
- Thermoelectrics
- Thermopower
- Young's modulus
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics