Stefanie Siebeneichler

I graduated from Istanbul Technical University with a B.Sc. in Metallurgical and Materials Engineering. In September 2014, I moved to Germany and started the Metallurgical Engineering master’s program at RWTH Aachen University. While earning my master’s degree, I attempt to understand mechanisms behind various behaviors in high-Mn steels. In order to achieve that I performed (i) ex-situ and in-situ synchrotron-XRD experiments to characterize the microstructure, considering phase fractions, microstrain, crystallite size and dislocation density, (ii) ex-situ small angle neutron scattering experiments to investigate the evolution of Mn-C clusters. In March 2017, I earned my master’s degree.

My project in SwedNess will be connected to a framework project based on the concept of designing hard metals with non­homogeneous structures, i.e. functional gradients, manufactured via powder metallurgy. In order to tailor non­homogenous composites consisting of multiple hard phases including cubic carbides and/or carbonitrides, it is necessary to control a number of structural parameters during sintering. Some of these structural parameters that will be considered within the project are phase fractions, carbide grain size, carbide grain shape, carbide nanostructure and residual stresses. Optimizing these structures relies heavily on, advanced bulk experimental characterization and computational modeling to understand and tailor the behavior of the material during processing. However, the only viable technique to probe the bulk of hard metals during processing at high temperatures (~1400 °C) and service is neutron scattering. Whilst small angle neutron scattering makes it possible to characterize the nanostructure, including nano-particle size, size distribution and volume fraction; neutron diffraction enables the measurement of residual stresses and phase fractions. Thus, neutron scattering will be exploited to study the microstructural evolution during processing of hard metals.

Publications

Magnetic phase diagram of the solid solution LaMn2(Ge1-xSix)2 (0 ≤ x ≤ 1) unraveled by powder neutron diffraction. A.V. Mudring, S. Siebeneichler, A. Ovchinnikov, B. Bosch-Santos, G.A. Cabrera-Pasca, R. Flacau, Q. Huang, A.W. Carbonari, D. Ryan. Research Square (2022) https://doi.org/10.21203/rs.3.rs-1228604/v1

From a Dense Structure to Open Frameworks: The Structural Plethora of Alkali Metal Iron Fluorophosphates. S. Siebeneichler, K. Verana Dorn, V. Smetana, A. Ovchinnikov, A.V. Mudring. Inorganic Chemistry (2022) https://doi.org/10.1021/acs.inorgchem.2c01205

Frustration and 120° Magnetic Ordering in the Layered Triangular Antiferromagnets A Fe(PO 3 F) 2 ( A = K, (NH 4 ) 2 Cl, NH 4 , Rb, and Cs). S. Siebeneichler, K.V. Dorn, A. Ovchinnikov, W. Papawassiliou, I. da Silva, V. Smetana, A.J. Pell, A.V. Mudring. American Chemial Society (2022). https://doi.org/10.1021/acs.chemmater.2c01916

The missing link between zeolites and polyoxometalates. G. Wang, K.V. Dorn, S. Siebeneichler, M. Valldor, V. Smetana, A.V. Mudring. ScienceAdvances (2022) https://doi.org/10.1126/sciadv.add9320

A soft chemistry approach to the synthesis of single crystalline and highly pure (NH4)CoF3 for optical and magnetic investigations. Stefanie Siebeneichler, Katharina V. Dorn, Volodymyr Smetana, Martin Valldor and Anja-Verena Mudring. The Journal of Chemical Physics (2020). https://aip.scitation.org/doi/10.1063/5.0023343

Ionothermal Synthesis, Structures, and Magnetism of Three New Open Framework Iron Halide-Phosphates. Guangmei Wang, Martin Valldor, Stefanie Siebeneichler, Magdalena Wilk-Kozubek, Volodymyr Smetana, and Anja-Verena Mudring. Inorg. Chem. 58, 19 (2019). https://doi.org/10.1021/acs.inorgchem.9b02028