Electron Beam Additive Manufacturing Processes for Aerospace

Two main branches of AM include powder bed fusion (PBF) and directed energy deposition (DED). DED technologies are unable to produce features and geometries as complex as powder bed fusion (PBF), but are generally much faster at adding material and can produce parts much larger. Additionally DED technologies can be used for a wider range of applications including coatings, repair, hybrid/feature addition, and large-scale near-net shape AM. Wire deposition offers a number of potential advantages over powder deposition. These advantages include higher productivity (5-20x faster deposition rates), cheaper feedstock material, high material utilisation (99% vs 85%), and completely free from powder inflicted porosity (though still susceptible to other causes of porosity).

Coaxial-wire EB DED xBeam system - One of the key barriers to uptake in some of these sectors is quality assurance of components produced by AM. This is particularly important for sectors such as aerospace which have specific quality assurance requirements due to the critical nature of the components. Of direct importance are the geometrical accuracy, internal build quality and material/microstructural properties of an AM build. In view of this, TWI has been working to address those needs. In particular, the xBeam EB-DED system has shown improved microstructure and material properties. This system was commissioned in 2021 as part of the ATI funded project OAAM. Preliminary trials have shown positive results, with avoidance of large grain formation in Ti. The latest results will be presented in this paper.