Scientific Events

Speaker: Dr. Christian Greiner Room: Seminar Room 1

Deformation mechanisms in metals under a tribological load

In 1950, Bowden and Tabor pointed out that in metallic tribological contacts the majority of the dissipated energy is spend to change the contacting materials’ microstructures. This – in part – explains why most metals show a highly dynamic subsurface microstructure under the shear load imposed by a sliding contact. In order to understand these processes, the elementary mechanisms accommodating the shear strain and acting in the material need to be revealed and understood. In this presentation, three examples of research avenues following this hypothesis will be given. During the very early stages of sliding, dislocations show an interesting self-organization phenomenon. How these structures interfere with twin boundaries and what might be learned about the dislocation motion under the slider will be the first part of the talk. Second, we will address how the high entropy alloy (HEA) CoCrFeMnNi reacts to a tribological load and whether there is evidence for mechanisms specific to HEAs. Third, we will focus our attention at tribo-chemically activated oxidation process studied for high-purity copper. [more]
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