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Antoine Alla. Wagstaff, Samuel Robert Massachusetts Institute of Technology. Department of Materials Science and Engineering. Massachusetts Institute of Technology. Department of Materials Science and Engineering 2017-05-11T19:58:13Z 2017-05-11T19:58:13Z 2017 2017 http://hdl.handle.net/1721.1/108965 986489869 Thesis: Sc. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017. Cataloged from PDF version of thesis. Includes bibliographical references. Macrosegregation of solute elements during casting operations has been a subject of observation, discussion, and research for several hundred years. The unique casting conditions found in the Direct-Chill aluminum casting process can lead to significant accumulation and depletion of solute elements throughout the cast product. In particular, the center of ingots are generally characterized by a depletion of up to 20 % of solute elements. In this investigation we confirm the dominant role mobile, solute-depleted grains play on magrosegregation along ingot centerlines. We propose that avalanche events drive the grains from the solidification front to the ingot center. In order to demonstrate and control this preferential settling, we propose the use of a turbulent jet to re-suspend the avalanching grains. An analytical expression is derived in order to optimize the dimension of the jet with the goal of minimizing centerline segregation. We then performed a series of experiments in order to validate the analytical expression across ingot dimensions and alloy families. Our experiments indicate that the use of a properly sized turbulent jet can reduce the degree of centerline segregation by up to 70% from standard conditions. by Samuel Robert Wagstaff. Sc.D. 115 pages eng Massachusetts Institute of Technology MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering. Jet processing of direct chill cast aluminum ingots Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="8ed28c83-1297-46ea-8502-57ce411083c2"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Jet processing of direct chill cast aluminum ingots</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2017</PublicationDate> <Authors> <Author> <DisplayName>Wagstaff, Samuel Robert</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering.</Keyword> <Abstract>Macrosegregation of solute elements during casting operations has been a subject of observation, discussion, and research for several hundred years. The unique casting conditions found in the Direct-Chill aluminum casting process can lead to significant accumulation and depletion of solute elements throughout the cast product. In particular, the center of ingots are generally characterized by a depletion of up to 20 % of solute elements. In this investigation we confirm the dominant role mobile, solute-depleted grains play on magrosegregation along ingot centerlines. We propose that avalanche events drive the grains from the solidification front to the ingot center. In order to demonstrate and control this preferential settling, we propose the use of a turbulent jet to re-suspend the avalanching grains. An analytical expression is derived in order to optimize the dimension of the jet with the goal of minimizing centerline segregation. We then performed a series of experiments in order to validate the analytical expression across ingot dimensions and alloy families. Our experiments indicate that the use of a properly sized turbulent jet can reduce the degree of centerline segregation by up to 70% from standard conditions.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>