Metal Additive Manufacturing Conference 2019

Additive manufacturing technologies allow manufacture of shapes that are not possible with conventional machining. This design freedom is very attractive for space hardware, as equipment performance could be significantly improved with increased shape complexity. Furthermore, conventional machining results in a high buy-to-fly ratio; i.e. more than 70% of the material is transformed to swarf, that must be recycled. Using additive manufacturing, the amount of material to be recycled is substantially decreased, limited to the light structure that may be needed to support the part while it is built. The potential of the Additive Manufacturing technologies is however impeded by the surface finish obtained on the as-manufactured material. Therefore, the influence of various surface treatments, commonly applied to space hardware, on the mechanical properties of three selected metallic alloys prepared by using Selective Laser Melting (SLM) and Electron Beam Melting (EBM) additive manufacturing processes have been investigated. Within this study, SLM using EOS M400 and EOS M280 equipment and in addition EBM using an ARCAM Q20 machine have been applied for sample manufacturing of three selected metallic alloys (SS316L, AlSi10Mg, Ti6Al4V). The influence of various surface treatments, e.g. anodization, Ni-coating, shot peening, chemical and electrochemical polishing, Hirtisation, and their applicability as well as to obtain low surface roughness has been investigated on these additive manufactured alloys. A trade-off considering various parameter relevant to space applications led to the selection of the best surface treatments for each alloy. The influence of the selected best surface treatments on the mechanical properties of these additive manufactured alloys have been investigated and compared to as-received samples. Special emphasize has been taken on their tensile, fatigue, and fracture toughness properties. In addition, their corrosion and stress corrosion cracking (SCC) behaviour including microstructural analysis using HR-SEM have been investigated. Furthermore, space relevant coatings and paints have been applied in order to investigate their adhesion under space environments.