Copper alloys have established a significant presence in the realm of metal additive manufacturing.
Copper, renowned for its exceptional thermal conductivity, has emerged as one of the most sought-after metals in the realm of additive manufacturing research and development. This attribute makes it particularly desirable for industries such as aerospace and electronics, where efficient heat exchange is of paramount importance. Copper's thermal conductivity ranks second only to silver among metals, yet it comes at a considerably lower cost. Copper alloys not only provide enhanced mechanical performance but also possess valuable electrical conductivity.
Commonly employed copper alloys in additive manufacturing encompass GRCop-42 and GRCop-84 (both containing copper, chromium, and niobium), C18150 (comprising copper, chromium, and zirconium), C18200 (consisting of copper and chromium), and GlidCop (combining copper with aluminum oxide). Copper alloy powders exhibit a gentle pink hue, while the resulting additive manufactured components showcase the classic radiance of copper.
NASA spearheaded the utilization of copper alloy forged components in the primary engines of space shuttles during the 1970s. The GRCop (copper-chromium-niobium) metal powder was developed by NASA metallurgist David Ellis as an improvement over earlier forging alloys and was employed alongside vacuum plasma spraying, a direct energy deposition (DED) additive manufacturing process capable of producing relatively straightforward large-scale structures.
With the advent of laser powder bed fusion (LPBF), copper powder found an ideal match within advanced additive manufacturing techniques. LPBF is a manufacturing process conducted within a hermetically sealed chamber that enables the creation of highly intricate internal geometries, tailored to meet the demands of cutting-edge rocket combustion chamber designs or electronic cold plate applications.
These intricate geometries, supporting additive manufacturing, capture the attention of engineers focused on designing lightweight rockets with novel propulsion configurations for applications such as carrier rockets and hypersonic systems. The rocket's thrust chamber necessitates materials capable of withstanding extreme temperatures and pressures during ignition. However, as it essentially functions as a heat exchanger, the chamber must also withstand the fluctuating flows of ultracold rocket propellants in its surroundings. Additive manufacturing's complex cooling channels, precisely crafted on the walls of the thruster, provide an exceptional balance to this fluctuating environment, surpassing the geometric possibilities achievable through any other manufacturing technique.
