TY - JOUR A1 - Brunner-Schwer, C. A1 - Petrat, T. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Highspeed-plasma-laser-cladding of thin wear resistance coatings: A process approach as a hybrid metal deposition-technology N2 - Plasma-Transferred-Arc (PTA) welding is a process that enables high deposition rates, but also causes increased thermal load on the component. Laser metal deposition (LMD) welding, on the other hand, reaches a high level of precision and thus achieves comparatively low deposition rates, which can lead to high processing costs. Combining laser and arc energy aims to exploit the respective advantages of both technologies. In this study, a novel approach of this process combination is presented using a PTA system and a 2 kW disk laser. The energy sources are combined in a common process zone as a high-speed plasma laser cladding technology (HPLC), which achieves process speeds of 10 m/min at deposition rates of 6.6 kg/h and an energy per unit length of 39 J/mm. KW - Highspeed-plasma-laser-cladding KW - Wear resistance KW - Deposition welding KW - Tungsten carbide KW - NiCrBSi PY - 2019 DO - https://doi.org/10.1016/j.vacuum.2019.05.003 SN - 0042-207X VL - 166 SP - 123 EP - 126 PB - Elsevier AN - OPUS4-48294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brunner-Schwer, C. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Laser-Plasma-Hybrid-Cladding: Possibilities in the combination 2 of arc and laser for deposition welding N2 - Plasma-Transferred-Arc (PTA) welding is a process that enables high deposition rates, but also causes increased thermal load on the component. Laser based Direct Energy Deposition (DED) welding, on the other hand, achieves a high level of precision and thus comparatively low deposition rates, which can lead to high processing costs. Combining laser and arc energy aims to exploit the respective advantages of both technologies. In this study, different possibilities of this process combination are presented using a PTA system and a 2 kW disk laser. This includes the combination in a common process zone as a highspeed plasma laser cladding technology (HPLC), which achieves process speeds of 10 m/min. Besides that it is being examined whether a pre-running plasma arc can be used to coat difficult-to-weld rail steel with a carbon content of 0.8 % due to a preheating effect. Furthermore, a smoothing of the coating by a plasma arc following the laser is investigated. T2 - Lasers in Manufacturing 2019 CY - Munich, Germany DA - 24.06.2019 KW - Plasma-Transferred-Arc KW - Direct Energy Deposition KW - highspeed plasma laser cladding KW - deposition welding PY - 2019 SP - 1 EP - 9 AN - OPUS4-48724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Petrat, T. A1 - Brunner-Schwer, C. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Microstructure of Inconel 718 parts with constant mass energy input manufactured with direct energy deposition N2 - The laser-based direct energy deposition (DED) as a technology for additive manufacturing allows the production of near net shape components. Industrial applications require a stable process to ensure reproducible quality. Instabilities in the manufacturing process can lead to faulty components which do not meet the required properties. The DED process is adjusted by various parameters such as laser power, velocity, powder mass flow and spot diameter, which interact with each other. A frequently used comparative parameter in welding is the energy per unit length and is calculated from the laser power and the velocity in laser welding. The powder per unit length comparative parameter in the DED process has also be taken into account, because this filler material absorbs energy in addition to the base material. This paper deals with the influence of mass energy as a comparative parameter for determining the properties of additively manufactured parts. The same energy per unit length of 60 J/mm as well as the same powder per unit length of 7.2 mg/mm can be adjusted with different parameter sets. The energy per unit length and the powder per unit length determine the mass energy. The laser power is varied within the experiments between 400 W and 900 W. Energy per unit length and powder per unit length are kept constant by adjusting velocity and powder mass flow. Using the example of Inconel 718, experiments are carried out with the determined parameter sets. In a first step, individual tracks are produced and analyzed by means of micro section. The geometry of the tracks shows differences in height and width. In addition, the increasing laser power leads to a higher dilution of the base material. To determine the suitability of the parameters for additive manufacturing use, the individual tracks are used to build up parts with a square base area of 20x20 mm². An investigation by Archimedean principle shows a higher porosity with lower laser power. By further analysis of the micro sections, it can be seen that at low laser power, connection errors occur between the tracks. The results show that laser power, velocity and powder mass flow have to be considered in particular, because a constant mass energy can lead to different geometric as well as microscopic properties. KW - Direct energy deposition KW - Porosity KW - Inconel 718 KW - Additive manufacturing KW - Laser metal deposition PY - 2019 SN - 2351-9789 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-50007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wonneberger, R. A1 - Gräf, S. A1 - Bonse, Jörn A1 - Wisniewski, W. A1 - Freiberg, K. A1 - Hafermann, M. A1 - Ronning, C. A1 - Müller, F. A. A1 - Undisz, A. T1 - Tracing the Formation of Femtosecond Laser-Induced Periodic Surface Structures (LIPSS) by Implanted Markers N2 - The generation of laser-induced periodic surface structures (LIPSS) using femtosecond lasers facilitates the engineering of material surfaces with tailored functional properties. Numerous aspects of their complex formation process are still under debate, despite intensive theoretical and experimental research in recent decades. This particularly concerns the challenge of verifying approaches based on electromagnetic effects or hydrodynamic processes by experiment. In the present study, a marker experiment is designed to conclude on the formation of LIPSS. Well-defined concentration depth profiles of 55Mn+- and 14N+-ions were generated below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using ion implantation. Before and after LIPSS generation, marker concentration depth profiles and the sample microstructure were evaluated by using transmission electron microscopy techniques. It is shown that LIPSS predominantly formed by material removal through locally varying ablation. Local melting and resolidification with the redistribution of the material occurred to a lesser extent. The experimental design gives quantitative access to the modulation depth with a nanometer resolution and is a promising approach for broader studies of the interactions of laser beams and material surfaces. Tracing LIPSS formation enables to unambiguously identify governing aspects, consequently guiding the path to improved processing regarding reproducibility, periodicity, and alignment. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser processing KW - Ion implantation KW - Transmission Electron Microscopy (TEM) KW - Stainless steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623990 DO - https://doi.org/10.1021/acsami.4c14777 SN - 1944-8244 (Print) SN - 1944-8252 (Online) VL - 17 IS - 1 SP - 2462 EP - 2468 PB - ACS Publications AN - OPUS4-62399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -