Additive Manufacturing of Aluminum Alloy Components Suitable for Marine Application

Additive manufacturing (AM) enables precise control of part shapes and can build geometries that cannot be conventionally produced. AM applications for the Navy include "print on demand" unmanned vessels or impact absorbers for hull protection. The objective of this thesis is to investigate metal AM for the fabrication of low-density water-tight buoyant objects and lightweight energy-absorbing structures to control failure modes. To achieve the objective, a liquid metal printer (Xerox ElemX) was used to print aluminum alloy parts. The CAD design of the buoyant object and energy-absorbing structures was to test the printer's ability to build cavities with overhang geometries. For each of the printed parts, observations of print quality were documented to validate the printer's capabilities and make recommendations to improve the subsequent print jobs. Supported by numerical analysis, key insights into the printers capabilities were gleaned and documented. The compressive test results for the energy-absorbing structures (void infill specimen) yielded a higher specific energy dissipation due to its lighter weight and well-structured internal voids. As a simple proof of concept to tailor failure modes, the strategic placement of the internal voids had also resulted in the intended max deformation to occur at the center of the specimen.