Detection of Floating Grains in DC Aluminum Casting

Free-moving "floating" grains have been linked to macrosegregation in direct-chill (DC) aluminum castings. The presence of these grains in the sump of a solidifying ingot has been acknowledged based on measurements of cast microstructures and by recent work using a turbulent jet to suspend solute-poor grains and minimize macrosegregation.1,2 Experiments in this study were designed to sample grains from the mushy region of two ingots, one cast by the standard method and another stirred with a turbulent jet. Measurements of floating grain size, concentration, morphology, and chemical composition are reported. The observations from the standard ingot offer a point of comparison for floating grain theories and casting models. The measurements from the stirred ingot show how the turbulent jet modifies the distribution, concentration and morphology of the floating grains.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2017

Author dc:creator

• Joseph, Carolyn M

Advisor dc:contributor.advisor

• Antoine Allanore.

• Materials Science and Engineering.

Statement dc:rights

• 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/109015

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/109015