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Fakultät Maschinenbau

Dominic Stangier, 2022

Titel Maßgeschneiderte tribologische Werkzeugaktivflächen für die Blechmassivumformung
Autor/Autor Dominic Stangier  
Verleger Vulkan Verlag GmbH  
Erscheinungsjahr 2022  
Gesamttitel Werkstofftechnologische Schriftenreihe ; Band 23  
Hochschulschrift Zugl.: Dortmund, Technische Universität Dortmund, 2022  
ISBN 978-3-8027-8830-7  
Sprache Deutsch  
Schlagwörter PVD-Technologie, Magnetron-Sputtering, Cr-basierte Hartstoffschichten, Oberflächenstrukturen  
Bezugsquelle 31,50€ beim Vulkan-Verlag  


Tool sided surface modifications play a decisive role in terms of increasing the service life and minimizing wear. However, the adjustment of friction conditions in forming processes, which have a superior influence with regard to the limits of the manufacturing technology and process control, have so far not been in the focus of investigations. Against this background, the limits of tribological adaptability are investigated for bionically surface structures and PVD thin film using the example of Sheet-Bulk Metal Forming (SBMF). This new class of forming technology represents a promising approach for the production of complex functional components made out of high-strength sheet materials. The property profile of the functional coatings synthesized by means of a combination of conventional and high-energy sputtering technology (DC/HiPIMS) was developed with the aid of multi-criteria optimization methods for the load collective of SBMF. The approaches for the improvement of ternary Cr-based nitride coatings follow the research hypothesis to generate an improved property profile by carbon incorporation, which is based on structural changes and the possible formation of nanocomposite structure.

Buchumschlag der Dissertation © LWT

With regard to the tribological investigations and the application potentials, a spectrum of functional, nature inspired surface structures as well as developed PVD coatings is evaluated in test rigs, which are specially developed for the load collective of real forming processes.

The investigations of this thesis prove that the adjustment of the chemical composition in the form of the carbon concentration has a decisive influence on the structural, mechanical and tribological properties of the synthesized thin films by means of hybrid PVD-coating processes. The identified a-C and a-CN- components cause a phase separation of the crystalline components in the thin film systems after exceeding the maximum solubility in the crystalline structure and can therefore be directly correlated to the changes in the property profile. The friction as a function of the carbon concentration could be traced back to the phase-specific evolution of the microstructure providing an improved property profile, which was evaluated for the optimized coating system. The type of manufacturing technology for the application of microstructures could be derived as a further decisive parameter for the production of high-performance tool surfaces. Compared to laser ablation, micromilling has a positive effect on the constitution of the surface-near region and thus enables good adhesion of the subsequently deposited PVD thin-film systems. With regard to the functionality of the surface structures, the developed processes achieved a near-net shaped coatings of the macroscopic geometry. The modification of tool surfaces with micro-structures also proves that, depending on the geometry, a direction-dependent as well as an isotropic control of the friction and thus of the material flow is possible. The application tests in incremental Sheet-Bulk Metal Forming processes show a reduction in the forming force as well as an improved mold filling for the coated tools and the structured surfaces of approximately 10 %. The verification of the service life for 10000 strokes in the sheet material DP600 was also demonstrated for a selected combinatorial approach of PVD coating and bionic surface structure.

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