Additive Manufacture of Refractory Metal Propulsion Components

Niobium alloy (C-103) reaction control system (RCS) chambers have been used on numerous NASA programs. However at elevated temperatures, the strength of C-103 decreases significantly. Higher strength niobium alloys have been developed, but these alloys lack the formability of C-103. Recently, Additive Manufacture (AM) of niobium and C-103 has been demonstrated using powder bed electron beam melting (EBM). A primary advantage of AM processing is its ability to produce complex components to net shape along with the incorporation of unique features. However, EBM-AM processing of niobium and C-103 results in elongated, columnar grains, which reduce mechanical properties as compared to a cold worked material. Therefore, the potential exists to develop and fabricate a higher strength niobium alloy by taking advantage of the net-shape forming capability of AM processing and circumvent the lack of formability of such high strength alloys. To demonstrate the feasibility of EBM-AM processing high strength niobium alloys, a parameters-characterization-properties study will be conducted during Phase I. During Phase II, the EBM-AM processing of high strength niobium alloys will be optimized and extensive materials properties testing will be conducted. The most promising results will then be used to produce a high strength niobium alloy RCS chamber.