Institute of Materials Science and Engineering

Increasing the defect tolerance of 100Cr6 by influencing the static and cyclic hardening behavior, using defined stabilized retained austenite

This project builds on important findings from our award-winning HiPerComp project, which showed that 100Cr6 bearing steel has an increasing defect tolerance with a higher amount of retained austenite. Besides the higher ductility and cyclic hardening potential of its austenitic phase, the transformation of retained austenite to α’-martensite in 100Cr6 led to a higher defect tolerance. The goals of this project are to analyze and model the relevant influences on the defect tolerances of 100Cr6. We are performing instrumented cyclic micro indentation tests (PhyBaLCHT) on differently heat-treated and alloyed samples, supplied by IWT Bremen and IEHK RWTH Aachen, respectively. Moreover, in order to examine the influence of operational temperatures on phase transformation, we are conducting cyclic indentation tests at ambient temperature and at temperatures up to 100 °C. Based on these studies, we will select the most promising conditions for thorough characterization of their mechanical and, in particular, cyclic properties.

From preliminary investigations so far, we have found differences in microhardness and cyclic hardening potential (eII) in material with different heat treatments, that these differences varied depending on the investigated test temperatures, and that they were caused by variations in the stability of the retained austenite.

This project is conducted in collaboration with the Steel Institute of RWTH Aachen University as well as the Leibniz-Institute for material-oriented technologies of IWT Bremen and is financially supported by the German Research Foundation (DFG)

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