Structure and energetics of long-period tilt grain boundaries using an effective Hamiltonian
Bibliographic record
Abstract
We have investigated the atomic structures of 44 〈110〉 symmetric tilt grain boundaries (GB's) with atomistic simulations using an embedded-atom method (EAM) potential for aluminum. The focus has been on examining the efficacy of the structural unit model in the context of very long period boundaries. Our studies, which have been carried out using two EAM potentials, of both the equilibrium and metastable structures of a number of boundaries, reveal that geometric arguments inherent in the structural unit model must be supplemented by energetic considerations. An effective Hamiltonian is introduced to this end which computes the energy of a string of structural units using two-body potentials between individual units. The potentials are calculated via a least-squares fit to the results of full atomistic represented by the effective Hamiltonian. Results based on as few as 16 inputs are very encouraging and clearly demonstrate the effectiveness of this method. This scheme lends itself to a straightforward extension to GB structure calculations at finite temperatures using Monte Carlo techniques.
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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) | 0.001 | 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 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".