Electron beam powder bed fusion of γ‐titanium aluminide: Effect of processing parameters on part density, surface characteristics and aluminum contentShow others and affiliations
2021 (English)In: Metals, ISSN 2075-4701, Vol. 11, no 7, article id 1093Article in journal (Refereed) Published
Abstract [en]
Gamma titanium aluminides are very interesting for their use in high‐performance applications such as aircraft engines due to their low density, high stiffness and favorable hightemperature properties. However, the pronounced brittleness of these intermetallic alloys is a major challenge for their processing through conventional fabrication methods. Additive manufacturing by means of electron beam powder bed fusion (EB‐PBF) significantly improves the processability of titanium aluminides due to the high preheating temperatures and facilitates complex components. The objective of this study was to determine a suitable processing window for EB‐PBF of the TNM‐B1 alloy (Ti‐43.5Al‐4Nb‐1Mo‐0.1B), using an increased aluminum content in the powder raw material to compensate for evaporation losses during the process. Design of experiments was used to evaluate the effect of beam current, scan speed, focus offset, line offset and layer thickness on porosity. Top surface roughness was assessed through laser scanning confocal microscopy. Scanning electron microscopy, electron backscatter diffraction (EBSD) and energydispersive X‐ray spectroscopy (EDX) were used for microstructural investigation and to analyze aluminum loss depending on the volumetric energy density used in EB‐PBF. An optimized process parameter set for achieving part densities of 99.9% and smooth top surfaces was derived. The results regarding microstructures and aluminum evaporation suggest a solidification via the β‐phase.
Place, publisher, year, edition, pages
MDPI, 2021. Vol. 11, no 7, article id 1093
Keywords [en]
Additive manufacturing, Aluminum evaporation, Electron beam melting, Electron beam powder bed fusion, Microstructure, Process parameters, Surface roughness, Titanium aluminide
National Category
Metallurgy and Metallic Materials
Research subject
Manufacturing Systems Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-86458DOI: 10.3390/met11071093ISI: 000676201500001Scopus ID: 2-s2.0-85109274778OAI: oai:DiVA.org:ltu-86458DiVA, id: diva2:1581877
Funder
German Research Foundation (DFG), 404665753
Note
Validerad;2021;Nivå 2;2021-07-27 (beamah)
2021-07-272021-07-272021-08-09Bibliographically approved