Microstructures in the Throat Region of Recovered Aluminum-Alloy Armatures

• Published in: IEEE transactions on magnetics Vol. 43; no. 1; pp. 422 - 425
• Main Authors: Watt, T.J., Bryant, M.D.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.01.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum; Aluminum alloys; Aluminum-alloy armature; Applied sciences; Electrical engineering. Electrical power engineering; Exact sciences and technology; Fracture mechanics; Grain boundaries; Heat treatment; Hydrogen; Magnetism; Mathematical analysis; Melting; Microstructure; Miscellaneous; Optical microscopy; Payloads; Photomicrographs; Pulsed power supplies; Steel; Surface cracks; Temperature; Throats; Various equipment and components; Proceedings; Aluminum-alloy armature; Electromagnetic launchers; Microstructure
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2006.887429

Previous work investigated macroscopic features of recovered aluminum alloy armatures launched at five different currents. Here, microstructural features of those armatures are explored. Several distinct heat-treatment regimes present near the armature throat surface include grain deformation, melting, and material ejection. Two distinct cracking mechanisms are present. The first-presumably due to liquation cracking-occurs at higher currents, is intergranular, and has cracking directions independent of armature geometry directions. The second-likely due to thermal stresses-is intragranular and has strong dependence on orientation. Detailed photomicrographs of the recovered armatures are presented, along with calculated dimensions of the heat-treatment zones and observed cracks