Kinetics and Morphology of Isothermal Transformations at Intermediate Temperature in 15CrMnMoV Steel
Bibliographic record
Abstract
Upper bainite (BU), lower bainite (BL) and granular structure (GS) are three distinguishable microstructures formed through isothermal treatment at temperature range from 350 to 520°C in 15CrMnMoV steel. Although long time isothermal holding leads to the mixed microstructures, single microstructure can be obtained in the initial stage of isothermal transformation when the total transformation fraction is less than 20%. The Arrhenius equations were used to determine the overall activation energies of the transformations in the steel with accuracy of ±8 kJ/mole. To ensure the determined overall activation energy is the true value for single microstructure rather than for a mixture of two or more microstructures, the present determination of the kinetic data of isothermal transformations was carried out in terms of the isothermally transformed fractions of 1 and 5% at various temperatures. Experimental results show that the overall activation energy for single microstructure is significantly different from that for mixed microstructure, which was measured in terms of 50% transformation. Upon the determined kinetic data and the morphology of the microstructures, together with consideration of the reported atom diffusion activation energies, following conclusions are achieved. In steels, the BU transformation is controlled by carbon diffusion in the austenite; while, the formation of BL is only partially governed by carbon diffusion in austenite. As a different microstructure from other two, the GS transformation is controlled by carbon diffusion and has the common features of both equiaxed ferrite and massive ferrite transformations. These results, can be used to further understand the formation mechanism of BU, BL and GS in the 15CrMnMoV steel.
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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 | 0.000 |
| 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) | 0.001 | 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 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".