MatHeMats - Distribution functions for the description of heterogeneous metallic microstructures

• Applicant: Professor Dr.-Ing. Ulrich Krupp, since 1/2021
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 382552347

Among the Advanced High Strength Steels (AHSS), Dual Phase (DP) steels and Complex Phase (CP) steels are the two most widely used steels in car body applications; the correlation between mechanical properties and microstructure features has been intensively studied for DP steels. However, despite the high strength and total elongation of DP steels, they are not the best choice for forming processes which require a good local formability. In comparison to DP steels, CP steels with a more heterogeneous microstructure have superior formability for many forming operations. This lead to an interesting question: is it possible to achieve more balanced mechanical properties of multiphase steels by tailoring the microstructure gradients? However, in order to answer this question, the existing description of CP microstructure, which considers only the vague fraction of simplified phases, is imprecise. A detailed description of the microstructure features of CP steels is required to investigate the correlation between the complex microstructure and the behavior during cold forming operations. Therefore, we will describe the heterogeneous microstructure of CP steels with the distribution function of several microstructure features, such as element distribution in different phases, dislocation density, grain size and morphology precipitates distribution and size; we intend to identify the correlation between the distribution functions and the mechanical properties on both global and local level. AGH will be responsible to develop the distribution functions of the microstructure features and will monitor them during the phase transformation of CP steel processing. RWTH will be responsible for the establishment of the correlation between the distribution functions of microstructure features and the mechanical properties through experiments and simulations.We consider that by this project the quantitative description of gradient microstructure features can be established and the new description can provide a more powerful and faster tool for the further development of AHSS. Meanwhile, the results of this project could also guide the design and manufacture of the CP steels to achieve more balanced mechanical properties in the future.

• DFG Programme: Research Grants
• International Connection: Poland
• Cooperation Partner: Professor Dr.-Ing. Maciej Pietrzyk
• Ehemaliger Antragsteller: Professor Dr.-Ing. Wolfgang Bleck, until 1/2021