TP1: Wear, corrosion and fatigue behaviour of functional surfaces produced by high-speed blanking

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Depending on the material and the selected process parameters, surfaces produced by high-speed blanking (HSB) can contain adiabatic shear bands (ASB). These are homogeneous zones, which are clearly delimited from the base material in microstructural terms and exhibit a significantly changed property profile compared to the surrounding material, such as a higher hardness. However, the structure-property relationships of high speed-blanked surfaces have remained largely unexplored to date. The focus of subproject 1 is therefore to provide a scientifically sound answer to the question of how HSB surfaces behave under tribological, corrosive and cyclic mechanical loading. This is directly linked to the need to gain a fundamental understanding of the mechanisms at work and thus the identification of process-microstructure-property relationships. A prerequisite for this is the interpretation of the results of the wear, corrosion and fatigue tests, which is carried out in coordination with the research group partners and aims at revealing correlations between the HSB surface properties, the process parameters and the resulting microstructure. The tribological investigations include various wear tests that represent different loading regimes. Thus, the material behavior of both flat and curved HSB surfaces is systematically investigated under grooving, sliding and rolling loads with and without intermediate media. The characterization of the corrosion behavior is performed across scales. On the one hand, the macroscopic behavior is determined in immersion and salt spray tests. On the other hand, the corrosion resistance of individual microstructural constituents of the ASB and the surrounding material is comparatively evaluated using a microcorrosion cell. Furthermore, by means of specially designed specimen geometries, the fatigue properties of ASB generated in a wide strain rate range (10²–10⁵ s-¹) are investigated. In addition, the residual stresses of HSB surfaces are measured by X-ray diffraction (XRD) to evaluate the material behavior. The macro- and micro residual stresses determined in this way are used on the one hand to interpret the results of the tribological, corrosive and cyclic mechanical tests, and on the other hand they represent important evaluation and validation variables for microstructure modeling or process simulation by the project partners.The research results obtained in subproject 1 are the basis for the evaluation of the service properties and thus the practical suitability of HSB surfaces. By means of feedback with the other subprojects, the results also enable direct influence on the design of the HSB process and thus targeted adjustment of the properties of the functional surface.