We propose to develop the know-how necessary to utilize additive manufacturing (AM) to fabricate hardware having the material and structural characteristics needed to meet exacting high-vacuum requirements of scientific R&D. Additive manufacturing (AM) offers the potential to realize the production of monolithic components while significantly reducing investments of resources including time, effort, and money. This project will target AM of large, complex 3D structures made of metal and alloy. At present, there is little data on high-vacuum properties of such build products. This deficit inhibits the use of direct energy deposition (DED) processes, which are well suited for rapid builds of large 3D products. Resolving this fundamental technology gap is a key factor motivating this effort. Numerous research and development (R&D) applications, both within fusion science and in other fields, require production of high-vacuum compatible components made of metals and alloys. Additive manufacturing can improve, over traditional methods, the fabrication and performance of the components. It (a) enables production of a 3D geometry as a single component from a 3D CAD model, (b) enables structures that can't be built with traditional methods, and (c) offers the potential to more rapidly and cost effectively realize a complex structure. Our aim is to leverage capabilities of cutting-edge hybrid-DED AM, to: advance processes capable of rapid and economical 3D builds of metals and alloys; develop, identify, and experimentally qualify single refractory metal and metal alloy build formulas suitable for high-vacuum applications, using components fabricated using arc/laser wire-fed/powder-fed DED processes; and merge the compilation into solutions enabling AM of high-vacuum chambers and components.