Model-based correlation between change of electrical resistance and change of dislocation density of fatigued-loaded ICE R7 wheel steel specimens

Weight-optimized component design as well as a reliable estimation of the lifetime of metallic materials and components require a comprehensive understanding of fatigue processes and a systematic investigation of the underlying fatigue behavior. This becomes even more important when designing highly loaded components such as wheels of high-speed passenger railway systems. Typically, mechanical stress-strain hysteresis measurements and increasingly different types of temperature and electrical resistance measurements are used to characterize the fatigue behavior and fatigue processes. Here, electrical resistance measurements provide significant information as they allow the detection of microstructural changes, e. g., through changes in dislocation density and structure. In addition, electrical resistance measurements can be considered in load increase and constant amplitude tests with inserted load-free sequences and in service load tests to characterize damage progress. In this paper, characteristic values of the change in electrical resistance were determined for ICE R7 wheel steel specimens and correlated with dislocation density, which was load- and cycle-dependent and determined through transmission electron microscopy.