Morphology evolution of plate-like precipitates in a polycrystalline Ni-based superalloy
Bibliographic record
Abstract
The formation of a dendrite arm-like interface, called protrusions, between plate-like precipitates and the surrounding matrix was studied in AD730™ Ni-based superalloy. The evolution in the morphology and reprecipitation sequence of γ′ particles after solution heat treatment has been investigated using Electron Backscatter Diffraction (EBSD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS). For the first time, atomic-scale investigations using High-Resolution Transmission Electron Microscopy (HR-TEM) revealed that protrusions tend to nucleate on the facet interface of the existing plate-like particles with a high coherency to the matrix. An analysis based on the application of the Brook equation was conducted, and a correlation was established between the frequency of protrusions and dislocation spacing, supporting the proposed dislocation-driven nucleation mechanism. TEM analysis revealed a gradient in chemical composition at the matrix-protrusion interface, which and analyzed in the framework of the dissolution and growth theories of precipitates. The results indicated that the protrusion occurred in a growth process during cooling, leading to the depletion of the main precipitating elements in the matrix in the adjacent zones. Using diffusion theory, element-specific diffusion behavior was analyzed, and it was revealed that Nb diffusion plays a critical role in protrusion evolution and governs the depletion of γ′-forming elements (Ni, Al, Ti, Nb) near the interface. The precipitation sequence and composition are analyzed in terms of the diffusion of γ′-forming elements. The evolution in the chemical composition of different precipitates indicated that the protrusions form after the precipitation of plate-like γ' and before that of secondary γ' on plate-like precipitates with about 0.27 % misfit. Based on the obtained results, it was concluded that the formation mechanism of protrusions is nucleation on misfit dislocations at the precipitate-matrix interface, and growth on {111} facet planes of plate-like precipitates. Additionally, the level of matrix supersaturation controls their growth kinetics.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".