Additive Manufacturing of cryogenic materials

Abstract

The use of pure copper and Inconel 718 as cryogenic materials has been well known in the cryogenic materials space. Despite their potential, little is known about the use of these materials in cryogenic environments regarding their ability to withstand these conditions when manufactured using Additive Manufacturing (AM) methods. AM has emerged as a promising production method due to its ability to produce complex geometries and near net-shape parts. Copper and Inconel 718 offer a wide range of uses in cryogenic applications, as Copper being highly conductive makes it ideal for electrical applications, whilst Inconel 718 serves well as an engineering material.In this paper, we demonstrate the Coldgas Spraying (CS) of copper and the Selective Laser Melting (SLM) of Inconel 718 and Scalmalloy as the AM processes of choice for each respective material. The main distinction between both processes is that CS is useful for rapid deposition of material in the range of several kg/h whereas SLM is limited to a range of several hundred g/h. However, CS can only yield bulk structures while SLM allows the production of fine and intricate structures due to the nature of their approaches.The work presented here was performed in the framework of a research project named AdHyBau. It is funded by the German government in which several partners from industry and academia seek to jointly develop a 500 kW output power electric drive for aviation applications which employs liquid hydrogen as a propellant for a fuel cell but also for advanced cooling to obtain very high power densities in the range of above 10 kW/kg.