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Session Chair: Moritz Späth, Institute of Photonic Technologies (LPT), Germany
Location:Room 3 ICM
2:45pm - 3:00pm
Comparison of ultrafast laser ablation of CrMnFeCoNi high entropy alloy to the conventional stainless steel AISI 304
David Redka1,4, Christian Gadelmeier2, Jan Winter1,3, Maximilian Spellauge1, Ján Minár4, Heinz P. Huber1
1Department of Applied Sciences and Mechatronics, Hochschule München University of Applied Sciences, Germany; 2Metals and Alloys, University of Bayreuth, Germany; 3Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universit¨at Erlangen-Nürnberg, Germany; 4New Technologies-Research Center, University of West Bohemia, Czech Republic
Ultrafast lasers as tools are nowadays mainly used in the field of high-precision laser micromachining. However, for technical applications, besides process optimization, the development of new functional materials is of crucial importance. In this work, we present a novel study on single-pulse laser ablation (530 fs, 1056 nm) of CrMnFeCoNi high entropy alloy (HEA), and compare results to the conventional stainless steel AISI 304. While HEAs are known to have a high damage resistance against high-energy particle radiation we find that this is not true for electromagnetic radiation, as the damage threshold of CrMnFeCoNi HEA is 0.24 J/cm2, which is lower than that of AISI 304 (0.27 J/cm2). A detailed analysis of the crater morphology, ablation depths as well as ablation volumes shows that the ablation mechanisms for both alloys are comparable, but contrary to expectations, CrMnFeCoNi HEA laser ablation is energetically more efficient in comparison to AISI 304.
3:00pm - 3:15pm
Electric field-assisted laser ablation of silicon in air by using ultrashort laser pulses
Yiyun Kang1, Garik Torosyan1, Hicham Derouach1, Mareike Schäfer1, Pavel N. Terekhin2, Bärbel Rethfeld2, Johannes A. L'huillier1
1Photonik-Zentrum Kaiserslautern e.V. and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany; 2Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
Precisely processing on silicon, as widely used material in electronic devices, has shown a rising interest in laser micromachining. To optimize this process, we apply an external electric field parallel to the laser beam axis during irradiation of samples with ultrashort laser pulses. When the electric field is turned on, the free electrons and holes are redistributed within silicon due to electron drift. The electrons can be localized near the surface area which is supposed to influence the laser excitation process. Thus, the external electric field influences the absorption process due to the reorganized spatial distribution of electrons. We investigated the effect of an applied static strong electric field during single- and multi-pulse treatment of silicon. We observe an enhancement of ablation depth by applying the electric field in the direction of laser radiation.
3:15pm - 3:30pm
Influence of the build angle dependent surface quality on the ultra-short pulsed laser ablation of additive manufactured AlSi10Mg samples
Simon Ruck1,2, David K. Harrison2, Anjali De Silva2, Max-Jonathan Kleefoot1, Harald Riegel1
1Aalen University, Germany; 2Glasgow Caledonian University, United Kindom
Additive Manufacturing (AM) been proved as a method to offer new possibilities for the production of highly complex parts. One new interesting but yet small field of application is the 3D printing of complex optical elements, e.g. complex reflective mirror optics with integrated lightweight structures. However, to achieve surfaces with an optical quality on additive manufactured metal parts, mostly mechanical machining processes such as diamond turning or pad polishing are used. The studying of laser material processing, e.g. ultra-short pulsed laser ablation as a post-processing method for additive manufactured optical components is of great importance. In this study, we investigate the influence of the initial surface quality on the ultra-short pulsed laser ablation process. Therefore, we varied the build angles of our samples and used different laser parameter setups to determine e.g. the ablation rate, achievable surface quality and process efficiency.