Microstructural insights into creep of Ni-based alloy 617 at 700 °C provided by electron microscopy and modelling
Bibliographic record
Abstract
In this work, microstructural changes during creep of Ni-based alloy 617 at 700 °C and 165 MPa have been investigated by electron microscopy, and complementarily modelled. Precipitate types, sizes and chemistry were determined by transmission- (TEM) and scanning electron microscopy (SEM). Apart from γ’ particles, MX and carbides, coarse μ-phase was found. Grain size, frequency of twins, deformation patterns and geometrically necessary dislocations were characterized by electron backscatter diffraction (EBSD). Based on measurements and literature data, creep behavior and a time-to-rupture (TTR) diagram of A617 have been numerically simulated at 700 °C in a range of 165 to 215 MPa with a new physical model. Our new creep model achieved excellent agreement with measured data and literature in terms of predicted creep life, times to 1% strain, minimum creep rate and microstructural evolution. We also succeeded in considering the varying ductility of the material in a novel damage law by implementing the reduction of area from fractured creep samples. Diffusion creep (coble creep) is considered in addition to dislocation creep in the model. The impact of diffusion creep is mostly visible at low stresses, leading to significant improvements within the TTR diagram.
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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".