FOR 5380: Functional surfaces through adiabatic high-speed processes: Microstructure, mechanisms and model development - FUNDAM³ENT

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High-speed blanking (HSB) represents an economically and ecologically interesting alternative to conventional cutting processes such as normal, fine or laser cutting. Especially for high-strength and ultra-high-strength steels, but also for light metals, HSB holds great potential with regard to the generation of blanked surfaces that can be used directly as functional surfaces without further mechanical, thermal or thermochemical post-processing steps. This is due to the fact that in HSB, depending on the material and the process parameters, adiabatic shear bands (ASB) can form, in which material separation then takes place. The resulting blanked surfaces are characterized by high hardness, low edge indentation and low roughness, and exhibit almost no burr. To date, however, there is a lack of fundamental understanding of the mechanisms leading to the formation of ASB in HSB. This in turn, however, is essential in order to be able to specifically harness the exceptional surface properties described. The FUNDAM³ENT research group is therefore dedicated to researching the material- and process-related factors influencing the formation of ASB in HSB in an interdisciplinary network.The overall objective of the research group is to develop a model based on materials science and process technology that describes shear band formation in HSB as comprehensively as possible, i.e. for different materials and in a wide range of process parameters. This is to be achieved by pooling expertise from the fields of materials science, materials engineering and production engineering. Important research questions to be addressed by the research group include, for example, the influence of various microstructural constituents and the deformation history on the tendency to shear band formation, or the question of whether ASB can also be produced in materials with good thermal conductivity, such as aluminum. Research is also being conducted to determine the extent to which the strain rate in the HSB process determines the microstructure, geometry and properties of the shear bands and whether the melting or recrystallization temperature of a material influences ASB formation and the resulting microstructure. Extensive experiments in different strain rate ranges of HSB (10²–10⁵ s⁻¹) generate a comprehensive process knowledge on the one hand and are the basis for a sound understanding of the microstructural effects occurring in the shear band on the other hand. This is supported by multi-scale simulation methods at the microstructural and process level. With the aid of systematic investigations of the material behavior of surfaces produced by HSB under tribological, corrosive and cyclic mechanical loading, an examination of the relationships between the blanking process, the microstructure and the resulting properties of the blanked surface is made possible.