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Please note that all times are shown in the time zone of the conference. The current conference time is: 4th Aug 2021, 01:48:34am CEST
Dalian University of Technology, Dalian, People's Republic of China
Laser-arc hybrid process was recently suggested as a feasible method for 3D printing the metal structural with high properties and low defects. To promote an understanding of the effect of laser on manufacturing process, this paper are performed to preparing aluminum alloy and cooper alloy using the integrating laser beam and tungsten inert gas (TIG) arc system. The microstructure evolution of aluminum alloy and copper alloy under different laser power are analyzed. Moreover, the elongation of the deposited aluminum alloy is improved on the higher tensile strength. The elongation of copper alloy sample is more than 40%. Relationship between the employed laser-arc manufacturing strateries and microstructure characteristics and mechanical properties are established. Laser-arc hybrid provides a new idea for additive manufacturing materials which are difficult to manufacture (high reflectivity, high thermal conductivity, et al.), and expand the application of laser additive manufacturing.
10:15am - 10:30am
Acoustic emissions of laser metal deposited NiTi structures
Julian Ulrich Weber1, Alexander Bauch1, Johannes Jahnke1, Claus Emmelmann2
1Fraunhofer IAPT, Hamburg, Germany; 2Institute of Laser and System Technologies (iLAS), Hamburg, Germany
Laser Metal Deposition (LMD) is an additive manufacturing process that enables the metal part production of complex near net-shape parts. Precise material deposition increases material efficiency and prevents the excessive use of costly materials. In a fully automated manufacturing process with minimized scrap production, these benefits are enabled by material specific process monitoring and parameter development.
Acoustic emissions were monitored for the LMD process of the costly shape memory alloy. Acoustic emission monitoring values were defined and evaluated regarding of NiTi structural defect formation. For the evaluation of defect formation, the degree of delamination for each specimen has been identified. Concurrent measurement of the oxygen content in the process chamber was carried out to correlate defects to the process atmosphere.
Distinct defect frequencies were detected for NiTi structures indicating delamination and cracks. The acquired data was used to design an LMD process control concept based on acoustic emission monitoring.
10:30am - 10:45am
Effect of atmosphere conditions on additive manufacturing of Ti4Al6V by coaxial W-DED-LB process
Eva Vaamonde, Rosa Arias, Pilar Rey, Iago Troncoso
AIMEN Technology Center, Spain
Additive Manufacturing is being a strategic tool for industrial applications even for large size structural parts where high deposition rates, as achieved by Directed Energy Deposition (DED) techniques based on wire deposition, are required. However, manufacturing of large components on reactive materials as titanium alloys requires specific atmosphere conditions to reach the specified properties on the deposited material. In this paper coaxial laser wire deposition (W-DED-LB) of titanium grade 5 alloy has been studied to achieve the highest deposition rate and process stability and the effect of protective conditions has been assessed. Three different configurations (local, inert chamber, local + inert chamber) were tested in order to bring a deep understanding of the influence of protective conditions on process stability, surface quality, metallurgy, hardness and oxygen content of deposited material.
10:45am - 11:00am
Processing of a low-alloyed case-hardening steel by means of DED-LB/M
Dominic Bartels1,2, Wolfgang Burgmayr1, Jonas Dauer1, Oliver Hentschel1,2, Michael Schmidt1,2
1Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Straße 3/5, 91052 Erlangen, Germany; 2Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
Low-alloyed steels are typically exposed to additional case-hardening post-processing to improve the mechanical properties in the case area of the material for increased hardness and wear resistance. Another possibility for improving these material properties is provided by in-situ alloying using laser-based directed energy deposition of metals (DED-LB/M). However, this requires basic understanding of the mechanisms when processing the base material. Within this work, different processing strategies for defect-free fabrication of a low-alloyed case-hardening steel are presented. This includes the correlation of geometrical properties and internal defects like pores or cracks with the applied process parameters. It is found that track geometry and diffusion zone are highly dependent on laser power and scanning speed. Additionally, hardness measurements are performed for analyzing the influence of different processing strategies on material properties. It is found that the corresponding material hardness varies inside a layer and that a hardness gradient is formed.