Relation of material microstructure and electromagnetic emission

• Applicant: Professor Dr. Markus Sause
• Subject Area: Measurement Systems ; Materials in Sintering Processes and Generative Manufacturing Processes ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392034898

Goal of this project is to establish the basic relationship betweenmaterial microstructure and generation of acoustic emission (AE) andelectromagnetic emission (EME) based on the fundamentals obtainedin previous DFG projects. Previous investigations have shown that allmaterial classes (metals, polymers, ceramics, minerals, naturalmaterials) show the formation of EME during fracture. Cracking insuperconducting materials has also provided evidence that evenmaterials with ideal charge mobility produce EME signals. This is notexpected in current models of the EME source and therefore cannotexplain the experiments. Therefore, new hypotheses on the origin ofEME in the model will be investigated. With regard to conductivity, theexisting electrostatic model is extended to an electrodynamic model,and the influence of ductility and dynamics of the crack motion duringthe fracture process is investigated in more detail. This will betargeted by further experiments using hydrogen embrittlement of steelalloys. Furthermore, it was found that EME can be measured undertribological stress of solids, which differs significantly from EME offracture processes in intensity and duration. Their origin shall beclarified by further experimental steps and the EME signals shall bemodelled to verify the hypothesis of their origin. For the differentmaterials investigated, model calculations will be performed todetermine the number of charge carriers that contribute to theformation of the EME signal at the surface of the crack. Specifically,this will be used to determine the amount of charge carrier disbalancebetween the crack surfaces, which is generally assumed to be thecause of the EME.

• DFG Programme: Research Grants