A Study of HAZ Microfissuring in a Newly Developed Allvac 718 Plus Superalloy
Bibliographic record
Abstract
Allvac® 718 PLUS™ (718 Plus) is a newly developed γ′ strengthened Ni-base superalloy with superior high temperature properties compared to its baseline superalloy, Inconel 718, but only limited information about its weldability is available.Electron beam welding response of this new superalloy was studied in two different pre-weld heat treated conditions.Microstructural characterization, prior to and after bead-on-plate electron beam welding, was done by optical microscopy, scanning electron microscopy and transmission electron microscopy.Two versions of 718 Plus with different concentrations of boron and phosphorus were investigated to study the effect of minor alloying elements on weldability.Grain boundary segregation of these minor alloying elements was studied using Secondary Ion Mass Spectrometer (SIMS).HAZ cracking due to liquation at the grain boundaries was observed in the alloys.The welding response of 718 Plus alloys was compared with that of Inconel 718 using two weldability evaluation techniques viz.-weld crack measurements in actual welds and hot-ductility measurements using Gleeble thermo-mechanical simulator.The results obtained by both the techniques were in agreement with each other and indicated that weldability of Inconel 718 was slightly better than that of 718 Plus alloy with normal boron and phosphorus concentration, although weldability of the higher boron and phosphorus version of 718 Plus alloy deteriorated significantly.The causes of cracking in 718 Plus alloys and the parameters affecting it are discussed and the welding response of the newly developed superalloy is assessed.
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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".