Determining the local mechanical responses of zirconium and hydrides using in situ indentation and crystal plasticity modeling
Bibliographic record
Abstract
Zirconium alloys are widely used in the cores of nuclear reactors, but their mechanical properties can deteriorate over time due to hydrogen embrittlement. This study employs in situ nanoindentation in a Scanning Electron Microscope (SEM) to investigate the local mechanical responses of zirconium and its hydrides. The indentation tests were conducted at different locations within the hydrides and their surrounding α-grains to study their orientation-dependent responses. High-spatial resolution Electron Backscatter Diffraction (EBSD) was used to measure the orientations of grains and hydrides, and to map the pre-indentation values into a Crystal Plasticity Finite Element (CPFE) model. The combination of numerical modeling and in situ experimentation enabled the study of how hydrides interact with one another and with the surrounding α-grains. It is shown that the presence of hydrides leads to different hardening mechanisms. The first mechanism occurs due to dislocations generated in the surrounding α-grains during hydride precipitation, prior to indentation, leading to a weaker hardening response. No apparent indentation-induced slip-hydride interaction was observed for the first hardening mechanism. The second mechanism is due to the interaction of indentation-induced slip bands of α-grains with hydride precipitates, which leads to a more noticeable hardening response. In addition, it was observed that the indentation of hydrides induces slip bands within them.
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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".