TY - JOUR A1 - Spranger, Felix A1 - Oliveira Lopes, M. A1 - Schirdewahn, S. A1 - Merklein, M. A1 - Hilgenberg, Kai T1 - Microstructural evolution and geometrical properties of TiB2 metal matrix composite protrusions on hot work tool steel surfaces manufactured by laser implantation JF - The International Journal of Advanced Manufacturing Technology N2 - The laser implantation–named technique aims to address the tribological problems frequently seen on tool surfaces during hot stamping. It is based on the creation of elevated dome- or ring-shaped hard structures on the surface of tool steels by a localized dispersing of hard particles. Therefore, a combination of the two distinct approaches that are normally used in surface Technology for optimizing friction and wear, i.e., surface texturing and surface material optimization, are realized in one processing step. In experimental studies, a localized dispersing of TiB2 particles in the surface layer of the hot work tool steel X38CrMoV5-3 was considered and compared with punctual laser–remelted textures. The structures (micro-) hardness was measured at top- and cross-sections. With the aid of a scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction the interaction between the hard particles and the substrate material were studied. From the results, an optimal parameter range was identified for laser implantation. To the investigation’s end, the implant geometry was measured by optical microscopy and White light microscopy. Furthermore, a mathematic model was introduced, which allows a prediction of the implant geometry as a response to the laser parameters. It was shown that the implantation of TiB2 particles leads to a significant hardness increase up to 1600 HV1 due to the dispersion of initial particles and an in situ precipitation of new titanium-rich phases. It was possible to create defect-free dome- and ring-shaped microstructures on the surfaces. It was also shown that the implants geometry highly depends on the applied laser parameters. The applied central composite design shows a good agreement with the experimental results. KW - Laser implantation KW - Surface texturing KW - X38CrMoV5-3 KW - TiB2 KW - Hot-Stamping PY - 2019 DO - https://doi.org/10.1007/s00170-019-04630-0 SN - 0268-3768 VL - 2019 SP - 1 EP - 23 PB - Springer-Verlag London Ltd. CY - London AN - OPUS4-49827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Hilgenberg, Kai T1 - Dispersion behavior of TiB2 particles in AISI D2 tool steel surfaces during pulsed laser dispersing and their influence on material properties JF - Applied Surface Science N2 - AISI D2 is one of the most applied cold-working tool steel for deep drawing operations, due to the materials good toughness and high wear resistance. However, since the lubricant-free deep drawing as well as the processing of high strength and ultra-high strength steel sheets remaining ongoing trends in the automotive industry, the tool surfaces need to be improved regarding their friction and wear behavior. For this purpose elevated micro textures can be applied. Since protruded micro features are predominantly affected by wear, a structuring process enabling the formation of suitable textures with high wear resistance is needed. In this paper surface texturing at microscale was conducted by laser implantation. This technique allows the fabrication of highly wear resistant, separated and elevated features (implants) on steel surfaces via a discontinuous dispersing of ceramic particles by pulsed laser radiation. The aim of this study was to investigate the techniques potential for the creation of wear resistant elevated micro features on AISI D2 tool steel surfaces by the application of TiB2 particles. The laser parameters (pulse power and length) were varied and a comparative material analysis on AISI D2 laser remelted spots and TiB2 localized dispersed zones was examined. High-speed camera recordings allowed the description of the particle insertion mechanism from pre-coatings during laser processing. Mechanical properties were analyzed by (micro-) hardness measurements at top and cross sections. The microstructure was investigated by optical microscopy, scanning electron microscopy (SEM), energy dispersive Xray spectroscopy (EDX) and X-ray diffraction (XRD). The implants geometrical properties (diameter, height, depth) were investigated by white light interferometry and optical microscopy. The experiments reveal that a pulsed laser remelting of AISI D2 leads to a significant hardness drop due to high retained austenite (γR) contents. Contrary, a localized dispersing of TiB2 particles leads to defect free dome- or ring-shaped elevated features with hardness values up to 1800 HV1. The high hardness values result from the dispersed TiB2 particles and an in-situ precipitation of new hard particle phases, which lead to a reduction of the γR content within the matrix. KW - Laser dispersing KW - Laser implantation KW - AISI D2 KW - TiB2 PY - 2019 DO - https://doi.org/10.1016/j.apsusc.2018.10.179 IS - 467-468 SP - 493 EP - 504 PB - Elsevier B.V. AN - OPUS4-46391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Lüchtenborg, Jörg A1 - Mühler, T. A1 - Wilbig, Janka A1 - Mohr, Gunther A1 - Villatte, T. A1 - Léonard, Fabien A1 - Nolze, Gert A1 - Sparenberg, M. A1 - Melcher, J. A1 - Hilgenberg, Kai A1 - Günster, Jens T1 - Enabling the 3D Printing of Metal Components in μ-Gravity JF - Advanced Materials Technologies N2 - As humanity contemplates manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments to safely work in space for years. The supply of spare parts for repair and replacement of lost equipment will be one key need, but in-space manufacturing remains the only option for a timely supply. With high flexibility in design and the ability to manufacture ready-to-use components directly from a computeraided model, additive manufacturing (AM) technologies appear extremely attractive. For the manufacturing of metal parts, laser-beam melting is the most widely used AM process. However, the handling of metal powders in the absence of gravity is one prerequisite for its successful application in space. A gas flow throughout the powder bed is successfully applied to compensate for missing gravitational forces in microgravity experiments. This so-called gas-flow-assisted powder deposition is based on a porous Building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. KW - Additive manufacturing KW - µ-gravity KW - Laser beam melting KW - Parabolic flight KW - 3D printing PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492190 DO - https://doi.org/10.1002/admt.201900506 SP - 1900506 PB - WILEY-VCH Verlag GmbH AN - OPUS4-49219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hilgenberg, Kai A1 - Daum, Werner A1 - Maierhofer, Christiane A1 - Altenburg, Simon A1 - Bruno, Giovanni A1 - Heckel, Thomas A1 - Skrotzki, Birgit A1 - Zerbst, Uwe A1 - Kranzmann, Axel A1 - Bettge, Dirk A1 - Sommer, Konstantin A1 - Seeger, Stefan A1 - Nitsche, Michael A1 - Günster, Jens A1 - Evans, Alexander T1 - Additive manufacturing at the BAM: We focus on Safety JF - Advanced Materials and Processes N2 - In Germany, the Federal Institute for Materials Research and Testing (BAM) is addressing challenges in the implementation of additive manufacturing on the industrial landscape for safety-critical applications. KW - Process development KW - Additive Manufacturing KW - In-situ Process Monitoring KW - Non-destructive Materials KW - Characterisation KW - Safety KW - Fatigue KW - Environment KW - Standardisation PY - 2019 UR - https://static.asminternational.org/amp/201910/22/ SN - 0882-7958 VL - 177 IS - 7 SP - 22 EP - 26 PB - ASM International CY - Materials Park, OH, USA AN - OPUS4-49780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -