Laser welding of Ti–5Al–5V–5Mo–3Cr
Bibliographic record
Abstract
Ti–5Al–5V–5Mo–3Cr butt joints were welded using a 4 kW continuous wave Nd:YAG laser. The effect of welding speed and defocusing distance on the weld quality was investigated. Welds with full penetration were achieved at a defocusing distance ranging from −1 to 0 mm and welding speeds from 2·25 to 6·0 m min−1. Underfill and porosity were the two main defects most frequently observed; however, within the optimum process window, these defects could be maintained to meet aerospace specification tolerances. The fusion zone consisted entirely of retained β with a refined dendritic morphology. Compared with the bimodal α+β microstructure of the base metal, dissolution of the α phase in the heat affected zone and the presence of entirely metastable/retained β phase in the fusion zone were observed, which led to a significant decrease in the HAZ and FZ hardness. To determine the tensile properties of the welds, an automated three-dimensional deformation measurement system was used to measure the local strain in the weld region. The yield strength and ultimate tensile strength increased with welding speed, achieving a maximum joint efficiency of 75%, albeit with a concomitant reduction in the ductility.On a soudé des joints de Ti-5553 bout à bout en utilisant un laser continu Nd:YAG de 4 kW. On a étudié l’effet de la vitesse de soudage et de la distance de défocalisation sur la qualité de la soudure. On a obtenu des soudures avec pénétration complète à une distance de défocalisation allant de −1 mm à 0 mm et à des vitesses de soudage de 2·25 à 6·0 m/min. Le manque de métal et la porosité étaient les deux principaux défauts les plus souvent observés, mais dans le cadre de la fenêtre optimale du procédé, on pourrait contenir ces défauts afin de satisfaire les tolérances de la spécification aérospatiale. La zone de fusion consistait entièrement de bêta résiduel à morphologie dendritique raffinée. Comparée à la microstructure bimodale a+b du métal de base, on a observé la dissolution de la phase a dans la zone affectée par la chaleur (HAZ) et la présence de la phase b entièrement métastable/résiduelle dans la zone de fusion (FZ), ce qui menait à une diminution significative de la dureté de la HAZ et de la FZ. Afin de déterminer les propriétés de traction des soudures, on a utilisé un système 3D automatisé de mesure de la déformation pour mesurer l’allongement local dans la région de la soudure. La limite d’élasticité et l’UTS augmentaient avec la vitesse de soudage, obtenant un rendement maximum du joint de 75%, quoique avec une réduction concomitante de la ductilité.
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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 | 0.001 | 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".