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Wire-based laser metal deposition for additive manufacturing of TiAl6V4: Basic investigations of microstructure and mechanical properties from build-up parts

 
: Klocke, Fritz; Arntz, Kristian; Klingbeil, Nils; Schulz, Martin

:

Gu, Bo ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Laser 3D Manufacturing IV : 30 January-2 February 2017, San Francisco, California, United States
Bellingham, WA: SPIE, 2017 (Proceedings of SPIE 10095)
ISBN: 978-1-5106-0631-9
ISBN: 978-1-5106-0632-6
Paper 100950U, 11 pp.
Conference "Laser 3D Manufacturing" <4, 2017, San Francisco/Calif.>
English
Conference Paper
Fraunhofer IPT ()
additive manufacturing; laser metal deposition; Titanium (TiAl6V4); mechanical properties; laser cladding; microstructure; Wire; Manufacturing Systems; Fertigungstechnik; Werkzeug- und Formenbau

Abstract
The wire-based laser metal deposition (LMD-W) is a new technology which enables to produce complex parts made of titanium for the aerospace and automotive industry. For establishing the LMD-W as a new production process it has to be proven that the properties are comparable or superior to conventional produced parts. The mechanical properties were investigated by analysis of microstructure and tensile test. Therefore, specimens were generated using a 4.5 kW diode laser cladding system integrated in a 5-Axis-machining center. The structural mechanical properties are mainly influence by crystal structure and thereby the thermal history of the work piece. Especially the high affinity to oxide, distortion and dual phase microstructure make titanium grade 5 (TiAl6V4) one of the most challenging material for additive manufacturing. By using a proper local multi-nozzle shielding gas concept the negative influence of oxide in the process could be eliminated. The distortion being marginal at a single bead, accumulated to a macroscopic effect on the work piece. The third critical point for additive processing of titanium, the bimodal microstructure, could not be cleared by the laser process alone. All metallurgical probes showed α-martensitic-structure. Therefore, a thermal treatment became a necessary production step in the additive production chain. After the thermal treatment the microstructure as well as the distortion was analyzed and compared with the status before. Although not all technical issues could be solved, the investigation show that LMD-W of titanium grade 5 is a promising alternative to other additive techniques as electronic beam melting or plasma deposition welding.

: http://publica.fraunhofer.de/documents/N-452501.html