Polycrystalline Modeling of the Effect of Texture and Dislocation Microstructure on Anisotropic Thermal Creep of Pressurized Zr-2.5Nb Tubes
Bibliographic record
Abstract
Abstract We have investigated the thermal creep of cold-worked Zr-2.5Nb tubes for a range of textures and stress states. The creep tests were performed on internally pressurized thin-wall standard (ratio of axial and transverse stress R≈0.5) and end-loaded (ratio of axial and transverse stress, 0.25<R<0.75) capsules 10 mm in diameter×40 mm long×0.5 mm wall-thickness at a stress of 300 MPa at 350°C where dislocation creep is the dominant operating mechanism. The tests showed an obvious correlation of anisotropic creep with the texture under different stress states. A self-consistent visco-plastic polycrystalline model based solely upon crystallographic texture showed a poor correlation with experimental results for radial basal textures, similar to that found previously for in-reactor creep. Hence texture alone is not sufficient to accurately predict the creep anisotropy. A modified self-consistent model is introduced to take into account different pre-existing anisotropic dislocation distributions (from cold-work) in different crystal orientations. Much better agreement with the experimental creep anisotropy was found, indicating that individual dislocation distributions in grains with different orientations are important in controlling the creep anisotropy. The predicted effect on creep anisotropy of introducing dislocation structures by a radically different strain path is very large.
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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".