Elastic modulus and internal friction of thermoelectric composites: Enthalpy–entropy compensation
Bibliographic record
Abstract
Mechanical spectroscopy measurements are reported on rods of (Bi1−xSbx)2Te3 and (Bi1−xSbx)2(Te1−ySey)3 polycrystalline thermoelectric (TE) composite alloys produced by mechanical alloying and hot extrusion. Low internal friction (Q−1) and large stiffness coefficients obtained in the 293–573 K range corroborate the improved elastic properties of these hot extruded and highly textured polycrystalline materials that have enhanced TE properties. Their stiffness shows a quadratic (decreasing) temperature dependence, and the value for most composites is larger than that of conventional single-phase random alloys and hot extruded bismuth telluride. One particular damping mechanism in Q−1, believed to be due to grain boundary motion, is thermally activated at temperatures higher than 420 K. The prefactor of the Arrhenius law correlates with the activation enthalpy (Δh) for every composite. It varies exponentially with Δh for more than six orders of magnitude for activation enthalpies up to 0.9 eV. The observation of this enthalpy–entropy compensation effect results from the existence of a maximum in energy dissipation in a linear regime of weak perturbations. This simple explanation is proposed to apply to this ubiquitous effect which has been observed in many areas of physics, chemistry, and biology.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".