Laser-direct energy deposition of the high γ′ LW 4280 Ni-based superalloy
Bibliographic record
Abstract
This study investigates the structure-properties relationships of LW 4280 processed using laser direct energy deposition. The alloy exhibited a typical dendritic microstructure in the as-deposited condition, with a significant microsegregation of alloying elements. Fine γ′ precipitates were present in the dendrite cores, while the interdendritic regions showed relatively coarser γ′ precipitates and Ta, Hf, and W-based carbides. The γ′ precipitates were enriched in Al, and Ta, whereas the γ matrix was rich in Cr, Co, W, Re and Mo. The application of a two-step sub-solvus heat treatment to the as-deposited specimens resulted in the growth of Ta, Hf, and W-based carbides, the formation of Cr-based carbides, and a bimodal distribution of roughly 49 % γ′ precipitates. Despite heat treatments, chemical variations persisted between dendrite cores and interdendritic regions. The difference in lattice parameters between the γ phase and γ′ precipitates was used to determine the lattice mismatch in both the as-deposited and heat-treated specimens. The heat treatment increased the hardness from 434 ± 15 HV 0.1 to 495 ± 17 HV 0.1 . Heat-treated specimens also exhibited excellent thermophysical and mechanical properties at both room temperature and elevated temperatures. Stress rupture tests at elevated temperatures revealed an outstanding rupture life, including 1084 h at 788 °C/448 MPa, 119 h at 871 °C/276 MPa, 458 h at 927 °C/179 MPa, and 93 h at 982 °C/138 MPa. Axial fatigue tests were conducted at 982 °C under stress amplitudes of 168, 134, and 121 MPa, resulting in fatigue lives of 3.5E+ 06, 1.0E+ 07, and 1.13E+ 07 cycles, respectively. • Crack-free, dense LW 4280 specimens were fabricated using laser–direct energy deposition. • A slower cooling rate resulted in the formation of γ′ precipitates during deposition. • Heat treatment resulted in the growth of γ′ precipitates and the carbides. • Heat-treated LW 4280 showed excellent mechanical properties at low and high temperatures.
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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".