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Direct‐Chill Casting of Large‐Scale Al–Cu Alloy Ingot Under Ultrasound: Distribution of Physical Fields and Analysis of Microstructure
The quality of the round ingot is one of the major factors that constrain the final performance of the large ring for aerospace applications. Herein, to reduce the defects from the start, ultrasound is applied to assist the direct‐chill casting of the large‐scale ingot (1100 mm diameter, 4680 mm len...
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Published in: | Advanced engineering materials 2021-10, Vol.23 (10), p.n/a |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The quality of the round ingot is one of the major factors that constrain the final performance of the large ring for aerospace applications. Herein, to reduce the defects from the start, ultrasound is applied to assist the direct‐chill casting of the large‐scale ingot (1100 mm diameter, 4680 mm length). Results show that coarse dendritic or petaloid α‐Al grains are reduced with the highest refining efficiency of 24.2% at the center part, which is attributed to the increased cooling rate induced by the ultrasonic vibration and ultrasound‐forced convection. Meanwhile, owing to the redistribution of Cu element under the ultrasound‐forced convection, Cu distributes more uniformly at the macro level and the Cu content in the Al matrix is increased. Under the combined effects of the lowered Cu enrichment between fragmented dendrites and the depressed growth in the narrowed mushy zone under ultrasound, the formation of coarsening divorced eutectic structure correspondingly decreases, with area fractions being reduced by 18.5%, 18.7%, and 24.8% at the center, r/2, and the edge, respectively.
The casting behaviors of large‐scale Al ingot (Φ1100 mm × 4680 mm) with and without ultrasound are systemically compared. The molten Al temperature distribution, flow pattern, and profile of the molten pool are also discussed. The ultrasound‐assisted casting can improve the flow pattern, enhance the redistribution of Cu element, and refine Al grains, resulting in the favorable performance of Al ingot. |
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ISSN: | 1438-1656 1527-2648 |
DOI: | 10.1002/adem.202100432 |