Longitudinal Seam Failure in Extruded AZ31 Alloy
Bibliographic record
Abstract
Research is currently being conducted on the feasibility of hydroforming extruded magnesium tubes to integrate multiple parts into a single hydroformed section. Among other applications, such sections would reduce the weight of both cars and planes, particularly when used in the vehicle frame. This would lead to either reduced fuel costs, or the ability to carry an increased payload. Magnesium generally has limited ductility, which in the case of the current extruded tubes is even further reduced at the extrusion seams. These are locations where the material flow separates and rejoins during extrusion and are unavoidable when a hollow profile die is used. When the tubes were stressed in a circumferential direction, tube ruptures consistently occurred along the extrusion seams of the tubes. This led to the current project, an inquiry into the exact cause of failure at these locations. The creation of irregularities at the seams, such as precipitate dispersions, local texture changes, grain size changes and entrained material, is discussed. These irregularities are considered together with their roles in producing the failures. The results are summarized and the most fruitful directions for future work are outlined.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".