Microstructural Evolution and Strength in Hot Working of ZK60 and other Mg Alloys
Bibliographic record
Abstract
The microstructures close to the gauge surface were observed by optical and transmission electron (TEM) microscopy in ZK60 (Mg-5.7Zn-0.65Zr) and in AZ31S (Mg-2.8Al-0.9Zn) after torsion testing over 180–450 °C and 0.01 to 1.0 s−1. The flow curves rose rapidly to a peak stress which was lower as temperature T rose and strain rate declined. At or below 240 °C, the stress fell rapidly to fracture but at or above 300 °C the curves descended less rapidly and extended into plateaus until failure. Clearly, grains that are not oriented for slip undergo twinning in the initial stages (ϵ ≤ 0.15) at all temperatures and some grains undergo the process as they rotate with strain. Basal slip proceeds in suitable grains and in the early formed twins leading to planar arrays. The stress concentrations at grain boundaries and in twins especially near intersections lead to slip on non-basal systems and to the formation of subgrains with greater dynamic recovery at higher T and lower ϵ. With increasing strain, misorientation builds up resulting in dynamic recrystallization (DRX), first at twin intersections with very fine cells and later at grain boundaries which have become quite serrated. Even after extensive straining at high temperatures, the new grains are found mainly as thick necklaces along the boundaries of the original grains leaving their centers with only basal slip; however, grains that twinned are likely to become completely replaced because of nucleation at twins.
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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".