Precipitation hardening of AA2195 DC cast alloy
Bibliographic record
Abstract
Direct chill cast ingot plates of AA2195 alloy have recently been used to manufacture large moulds for the plastic and automotive industries. The precipitation hardening behaviour of AA2195 direct chill cast materials was investigated using hardness measurements, differential scanning calorimetry and transmission electron microscopy. Aging treatments were performed at 125, 140 and 150°C for up to 96 h. The aging behaviour of the alloy varied significantly relative to the aging temperature. At 125°C, the alloy displayed a low age hardening rate related to the formation of GP zones and ultrafine θ″-Al2Cu precipitates. At 140°C, two different age hardening rates were observed, corresponding to the precipitation of θ″-Al2Cu phase during the early stages of aging and to the precipitation of both plate-like θ′-Al2Cu and T1-Al2CuLi phases over prolonged aging times. The kinetics of the aging process were accelerated at 150°C, and a strengthening effect was induced primarily by the θ′-Al2Cu and additionally by T1-Al2CuLi precipitates. These different aging behaviours enable the AA2195 direct chill cast alloy to provide a range of desirable combinations of mechanical properties, satisfying most design requirements for large mould applications.On a utilisé récemment des tôles d’alliage AA2195 de lingot de coulée semi-continue pour usiner des moules de grande taille pour l’industrie du plastique et de l’automobile. On a examiné le comportement de durcissement par précipitation de matériaux de coulée semi-continue d’AA2195 en utilisant les mesures de dureté, l’analyse calorimétrique différentielle et la microscopie électronique en transmission. On a effectué des traitements de vieillissement à 125, à 140 et à 150°C, jusqu’à une durée de 96 h. Le comportement de vieillissement de l’alliage variait significativement par rapport à la température de vieillissement. À 125°C, l’alliage exhibait une faible vitesse de durcissement par vieillissement reliée à la formation de zones GP et de précipités ultrafins d’θ″-Al2Cu. À 140°C, on a observé deux vitesses différentes de durcissement par vieillissement, correspondant à la précipitation de la phase θ″-Al2Cu durant les étapes initiales du vieillissement et à la précipitation des deux phases de type stratifié, θ′-Al2Cu et T1-Al2CuLi, à des durées prolongées du vieillissement. La cinétique du procédé de vieillissement s’accélérait à 150°C et un effet de renforcement était induit primairement par l’θ′-Al2Cu et en outre par les précipités de T1-Al2CuLi. Ces différents comportements de vieillissement permettent à l’alliage AA2195 de coulée semi-continue de fournir une gamme de combinaisons désirables de propriétés mécaniques, satisfaisant la plupart des exigences de conception pour applications dans les moules de grande taille.
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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".