a: © Polizeiinspektion Stade b: © Fa. Schaeffler d:  ©RWTH Aachen c und e: © Max-Planck Institut für Eisenforschung GmbH

Research Projects

The unpredictable failure mechanism of White Etching Crack (WEC) formation in bearing steels urgently demands in-depth understanding of the underlying mechanisms in the microstructure. The first breakthrough was achieved by relating the formation of White Etching Areas (WEAs) to successive WEC movement. more
Since white etching crack (WEC) phenomena primarily occur in steels containing high amounts of carbon, we specifically elucidate the role of carbon in this failure mechanism in bearings. more
Within this project we aim to systematically understand carbide decomposition by applying different potential factors (deformation, heat, electric current, and hydrogen absorption) on a Fe-C binary pearlite. High resolution techniques, such as electron microscopy and atom probe tomography, are used for characterization of the underlying mechanisms. more
Severe plastic deformation leads to cementite decomposition in pearlitic and martensitic alloys, resulting in high-strength nanocrystalline ferrite. This effect can be employed to strengthen pearlitic wires but it can also be associated with material failure by white etching cracks (WECs) more
The aim of the project is to elucidate the mechanism behind white etching crack (WEC) formation in bearing applications and to create materials that are resistant to this failure mechanism. The most prominent example for WEC failure are gear bearings of wind turbines. However, also many other applications from rails, over clutches to washing machines are concerned. more
By characterizing the high N alloyed martensitic stainless bearing steel X30CrMoN15-1 in-depth, we rationalize the exceptional white etching crack resistance of this complex technical alloy in terms of the different grain boundary segregation behavior between nitrogen and carbon, the mechanical and thermodynamic stability of the precipitates, and the cleanliness of the steel. more
The interplay of mechanical loads and body fluids leads to local decomposition and surface alloying effects in the modular taper joints of hip implants.  We are investigating this engineering problem with state-of-the art correlative atom probe tomography and electron microscopy techniques. more
Well-functioning and failed CoCrMo implants have been shown to release different concentrations of Co, Cr and Ni into the blood.  The role of carbide phases present in CoCrMo alloys on the corrosion or dissolution mechanisms needs to elucidated in order to minimize the release of metal ions from an implant into the body more
In collaboration with Prof. Dr. Helge-Otto Fabritius, Hamm-Lippstadt University of Applied Sciences, we investigate the potential of biomimetic substances such as hydroxyapatite for optimization and development of new formulations for prevention and treatment of a number of  prevalent clinical conditions in teeth. more
There is a high interest to understand the response of metallic (amorphous) glasses to rapid heating and plastic deformation. These two topics are addressed in this project using correlative electron microscopy and atom probe tomography. more
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