Electron Beam Wire-fed Deposition of Titanium Alloys for Repair Applications
Notice bibliographique
Résumé
AM has revolutionized manufacturing with its advantages and applicability in various sectors. In aerospace, components are fabricated from high-strength materials, such as titanium alloys. Hence, application of AM to fabricate and repair Ti6Al4V alloy has been of research interest. However, during service, the components are subjected to wear and fatigue stresses. Though part replacement may be the only option in the case of extensive damage, considering the cost and sustainability challenges, the repair is beneficial. Therefore, reliable repair procedures are required.A fully coupled 3D transient thermo-mechanical finite element model was developed to simulate the EBWF process. The model has been validated using multiple EBWF Ti6Al4V coupons. Wall geometry wrought plates were used as substrates. Thermocouple measurements were recorded to validate the simulated thermal cycles. Model was proven to be reliable in terms of predicted temperatures, residual stresses, and distortion. The average error in the model was 3.7% in terms of thermal predictions. Mechanical validation measurements showed that the maximum deviations in the model were 100 MPa in residual stresses and 0.05 mm in distortion. Tensile residual stresses were observed in the deposit and the heat-affected zone, while compressive stresses were observed in the substrate.The effect of initial residual stresses on the repair integrity is critical. Hence, the effect of the initial substrate microstructure and residual stress on the final deposit properties was investigated. Three types of substrates were studied: wrought, LPBF, and EBWF plates. The results revealed that the EBWF additive repair for Ti6Al4V <350 μm yielded distortion and <150 MPa residual stresses. On the substrate stress relaxation was more dominant than residual stress development during EBWF. This showed initial residual stress of the substrate had no effect on the final residual stresses. Similar mechanical properties were observed for all substrate conditions. Deposited test specimens had YS and UTS values ranging between 800-830 MPa and 860–880 MPa, respectively. All tested specimens deformed and ruptured from deposited material above the interface. The similar mechanical properties of the interface were correlated with the microstructural features such as layer bands and α colonies.This study also focused on the microstructural evolution and local properties of the Ti6Al4V EBWF deposits. The investigation focused on extending the understanding related to the microstructural zones of transient and steady-state as well as banding phenomenon in EBWF deposited Ti6Al4V. Mechanical properties of these zones were evaluated through microhardness and miniature tensile testing. Although microstructure observed in these zones were different in terms of morphology and scale, their tensile properties were similar. The measured properties of the miniature specimens were comparable with E8 standard sized specimens, higher than the ASTM F1108 cast and lower than the AMS 4911P wrought Ti6Al4V standards.Finally, the expertise gained in previous studies was combined to perform a post-service Ti8Al1Mo1V compressor blade tip repair using Ti6Al4V wire and EBWF deposition technology. Residual stresses on the compressor blade after repair were lower than initial residual stresses due to the stress relaxation. The highest distortion after the repair was below 100 μm. Previously utilized miniature tensile testing has been adopted to investigate interface strength of the repair. The YS, UTS and elongation at break of the tested miniature specimens ranged between 869-906 MPa, 925-956 MPa, and 10-11%, respectively. Tensile properties of the interface met the minimum requirement of AMS 4911P wrought specifications. Fractography analysis showed that failure occurred in the additively deposited repair section. This work demonstrated that EB-WF deposition technology can be successfully utilized for repair applications
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».