Electrical conductivity of additively manufactured conductors at cryogenic temperatures

High-performance electrical conductors are crucial for advanced cryogenic applications, most notably in superconducting magnet systems, fusion reactors, and high-efficiency power-dense electrical machines. Exploring future electrical machines for the electrification of aerospace, additive manufacturing (AM) can offer enhanced geometrical complexity, higher slot fill factors, advanced loss management as well as direct thermal cooling of the windings via liquid or gaseous cryogenic fluids. This presentation explores the application of Additive Manufacturing (AM), specifically Laser Powder Bed Fusion (LB-PBF), to fabricate high-purity electrical components from aluminium and copper. Detailed process mapping exploring laser energy density, build angle, and powder quality, is undertaken to correlate resulting material density and defects with electrical properties. X-ray computed tomography was used to observe porosity, which was found to concentrate around the joint between contours and fill hatches, leading to concerns that high frequency properties will be degraded. Direct current electrical characterisation was conducted at ambient temperature and at 77 K in liquid nitrogen, demonstrating conductivities of up to 420% International Annealed Copper Standard (IACS) for aluminium and 820% IACS for copper, within the range of traditionally processed materials. The findings confirm the viability of AM for creating next-generation, highconductivity components essential for future cryogenic technologies such as electrical propulsion of aircraft.