Friction-Stir-Processing of Aluminum-Armor and Alumina-Encapsulated Armor

The Littoral Combat Ship (LCS) is a naval vessel developed to deal with unconventional post-cold-war threats. To protect valued assets, and still maintain the ships maneuverability and speed, the U.S. Navy requires lighter-weight armor. NanoCoatings, Inc. and South Dakota School of Mines & Technology propose a plastic-deformation mechanical treatment, friction-stir-processing (FSP), to enhance the performance of aluminum (Al)-alloy armor and encapsulate lightweight ceramic armor. The finer-grained FSP microstructure increases ductility and has been shown in preliminary ballistic tests to prevent penetration of an Al-alloy plate, compared to full-penetration of an equivalent areal-density Al plate. Our team proposes two unique concepts: 1) FSP of Al-alloy armor surfaces and 2) Encapsulation of alumina-ceramic tiles by FSP within an Al-armor package. Characterization will include: 1) x-radiography, 2) metallographic analysis, and 3) mechanical-property testing. Armor packages will be screened by ballistic tests, at the University of Dayton Research Institute, for comparison with baseline Al-armor. In the Phase I option, V50 ballistic tests will be conducted on a down-selected armor concept and a demonstration armor panel, showing form and fit, will be fabricated for trial integration with LCS. Preliminary process specifications will be developed and an analysis of manufacturing process scaling will be performed.