Additive Manufactured Material

Sammanfattning: This project treats Additive Manufacturing (AM) for metallic material and the question if it is suitable to be used in the aeronautics industry. AM is a relatively new production method where objects are built up layer by layer from a computer model. The art of AM allows in many cases more design freedoms that enables production of more weight optimized and functional articles. Other advantages are material savings and shorter lead times which have a large economic value. An extensive literature study has been made to evaluate all techniques on the market and characterize what separates the different processes. Also machine performance and material quality is evaluated, and advantages and disadvantages are listed for each technique. The techniques are widely separated in powder bed processes and material deposition processes. The powder bed techniques allow more design freedom while the material deposition techniques allow production of large articles. The most common energy source is laser that gives a harder and more brittle material than the alternative energy sources electron beam and electric arc. Two specific techniques have been selected to investigate further in this project. Electron Beam Melting (EBM) from Arcam and Wire fed plasma arc direct metal deposition from Norsk Titanium (NTiC). EBM is a powder bed process that can manufacture finished articles in limited size when no requirements are set on tolerances and surface roughness. NTiC uses a material deposition process with electric arc to melt wire material to a near-net shape. The latter method is very fast and can produce large articles, but have to be machined to finished shape. A material investigation have been made where Ti6Al4V-material from both techniques have been investigated in microscope and tested for hardness. For the EBM-material have also surface roughness and weldability been investigated since the limited building volume often requires welding. The materials have mechanical properties better than cast material with respect to strength and ductility, but not as good as wrought material. Test results show that the difference in mechanical properties in different directions is small, even though the material has an inhomogeneous macrostructure with columnar grains in the building direction. The EBM-material has a finer microstructure and a stronger material and, in combination with improved design freedom, this technique is most suitable for aerospace articles when the weldability is good and it is possible to surface work where requirements of the surface roughness are set. Keywords: Additive Manufacturing, Aeronautics, Titanium