Research focus

The Department of Granularity of Structural Information in Materials Engineering (GWS) at the University of Kassel is at the forefront of developing high performance metallic materials through a deep understanding of the relationship between process, microstructure and properties. Our research uses multiscale characterization techniques to develop materials from the micrometer to the atomic scale, with a focus on improving mechanical properties, durability and sustainability for various industrial applications.

A central pillar of our work is the development of sustainable metallic materials that aim to minimize environmental impact through improved recyclability, reduced energy consumption and extended lifetime. In addition, we are pioneering research into hydrogen embrittlement, a critical challenge for the hydrogen energy industry, to create hydrogen-resistant metallic materials. These efforts are critical to the safe adoption of hydrogen as a clean energy carrier and are in line with our commitment to contribute to a sustainable energy future.

By integrating advances in sustainable materials and addressing key challenges in hydrogen energy applications, our GWS is dedicated to providing innovative materials for a more sustainable world.

Research area

The research group specializes in developing nanostructured metallic materials by combining simulation tools and experimental approaches. Dedicated to advancing materials development, the focus is on achieving superior mechanical properties while reducing manufacturing costs and gas emissions. Through systematic studies of the process-microstructure-property relationship at multiple scales, the group aims to push the boundaries of material engineering to meet the evolving demands of modern technology and industry. The primary aim is on engineering materials at the micro and nanoscale, resulting in significant improvements in strength, durability, and formability, paving the way for both current and next-generation applications.

Selected publications:

[1] W. Song: Nano-Engineering of High Strength Steels. Nature Springer, 2024.

[2] W. Song, J.von Appen, P. Choi, R. Dronskowski, D. Raabe, W. Bleck: Atomic-scale investigation of ε and θ precipitates in bainite in 100Cr6 bearing steel by atom probe tomography and ab initio calculations. Acta Materialia, 61 (2013) 7582-7590.

[3] H. Fu, W. Song, E. I. Galindo-Nava, P. E. J. Rivera-Díaz-del-Castillo: Strain-induced martensite decay in bearing steels under rolling contact fatigue: Modelling and atomic-scale characterisation. Acta Materialia, 139 (2017) 163-173.

[4] Y. Ma, B. Sun, A. Schökel, W. Song, D. Ponge, D. Raabe, W. Bleck: Phase boundary segregation-induced strengthening and discontinuous yielding in ultrafine-grained duplex medium-Mn steels. Acta Materialia, 200 (2020) 389-403.

[5] Sun, Y. Ma, N. Vanderesse, R. S. Varanasi, W. Song, P. Bocher, D. Ponge, D. Raabe: Macroscopic to nanoscopic in-situ investigation on yielding mechanisms in ultrafine grained medium Mn steels: Role of the austenite-ferrite interface. Acta Materialia, 178 (2019) 10-25.

The research group is dedicated to using sophisticated nano-characterization technology to investigate the structural information of atomic structures and local chemistry, which is essential to ultimately understand its contribution to physical properties. Our employed techniques such as synchrotron radiation, neutron scattering, and positron annihilation spectroscopy offer unparalleled precision in probing the atomic structures and dynamics of nanostructure evolution. Atom probe tomography (APT) allows for three-dimensional compositional mapping at the atomic scale, enabling detailed analysis of elemental distributions and their effects on material properties. Transmission electron microscopy (TEM) and high-resolution TEM (HR TEM) provide high-magnification imaging and atomic-level resolution, respectively, allowing to visualize defects, phase boundaries, and crystallographic structures etc. These advanced characterization techniques collectively contribute to the design and development of materials with superior performance, tailored for specific applications in modern technology and industry.

Selected publications:

[1] G. Casillas, W. Song, A.A. Gazder: Twins or the omega phase: Which is it in high carbon steels? Scripta Materialia, 186 (2020) 293-297. 

[2] Y. Ma, W. Song, W. Bleck: Investigation of the microstructure evolution in a Fe-17Mn-1.5Al-0.3C steel via in situ synchrotron X-ray diffraction during a tensile test. Materials 10 (2017) 1129. 

[3] W. Song, Aurel Radulescu, L. Liu, W. Bleck: Study on a high entropy alloy by high energy synchrotron X-Ray diffraction and small angle neutron scattering. Steel research international, 88 (2017) 1700079. 

[4] W. Song, D. Bogdanovski, A. Yildiz, J.E. Houston, R. Dronskowski, W. Bleck: On the Mn–C short-range ordering in a high-strength high-ductility steel: small angle neutron scattering and Ab initio investigation. Metals, 8 (2018) 44. 

[5] X. Shen, H. Qiao, W. Song, W. Bleck: Near-atomic scale characterization of Mn-gradient in reverted Austenite in hot-rolled medium-Mn steels. Steel research international, 94 (2023) 2300145. 

The research focus lies in investigating the mechanisms and impact of hydrogen embrittlement on metallic materials, a critical issue affecting the reliability and durability of infrastructure and high-performance metallic materials. Hydrogen embrittlement leads to premature brittleness and fractures, posing significant risks to pipelines, hydrogen infrastructures, aerospace components etc. By employing advanced characterization and modelling techniques, we aim to understand and mitigate the effects of hydrogen on metallic materials through novel micro-/nanostructural design. Addressing the material challenges posed by hydrogen embrittlement is essential for the sustainable and safe deployment of hydrogen technologies for various industrial applications.

Selected publications:

[1] X. Lu, Y. Ma, Y. Ma, D. Wang, L. Gao, W. Song, L. Qiao, R. Johnsen: Unravelling the effect of F phase on hydrogen-assisted intergranular cracking in nickel-based Alloy 725: Experimental and DFT study. Corrosion Science, 225 (2023) 111569. 

[2] Q. Wang, S. Xu, J. Lecomte, C. Schuman, L. Peltier, X. Shen, W. Song: Crystallographic orientation dependence of hydride precipitation in commercial pure titanium. Acta Materialia, 183 (2020) 329-339. 

[3] X. Lu, Y. Ma, M. Zamanzade, Y. Deng, D. Wang, W. Bleck, W. Song, A. Barnoush: Insight into hydrogen effect on a duplex medium-Mn steel revealed by in-situ nanoindentation test. International Journal of Hydrogen Energy, 44 (2019) 20545-20551. 

[4] D. Wan, Y. Ma, B. Sun, N. Razavi, D. Wang, X. Lu, W. Song: Evaluation of hydrogen effect on the fatigue crack growth behavior of medium-Mn steels via in-situ hydrogen plasma charging in an environmental scanning electron microscope. Journal of Materials Science & Technology, 85 (2021) 30-43

[5] X. Shen, W. Song, S. Sevsek, Y. Ma, C. Huter, R. Spatschek, W. Bleck: Influence of microstructural morphology on hydrogen embrittlement in a medium-Mn steel Fe-12Mn-3Al-0.05C. Metals, 9 (2019) 929. 

Our research mission is to advance the development and implementation of sustainable metallic materials that meet the increasing demands for environmental responsibility and resource efficiency. In the face of global challenges, e.g., climate change and resource depletion, our research focuses on developing metallic materials with superior performance, reduced environmental impact, and enhanced recyclability. By employing simulation-based alloy design, green manufacturing processes, and life-cycle analysis, we aim to minimize the ecological footprint and strategic-critical element dependence of metallic materials.

Selected publications:

[1] U. Krupp, A. Gramlich, T. Hinrichs, W. Song, H. Springer: Cu-Tolerant High-Strength Steels for a Circular Economy. Conference: Materials Science and Engineering (MSE) Congress 2022.

[2] D. Görzen, H. Schwich, B. Blinn, W. Song, U. Krupp, W. Bleck, T. Beck: Influence of Cu precipitates and C content on the defect tolerance of steels. International Journal of Fatigue, 144 (2021) 106042. 

[3] S. Wesselmecking, M. Haupt, Y. Ma, W. Song, G. Hirt, W. Bleck: Mechanism-controlled thermomechanical treatment of high manganese steels. Materials Science and Engineering: A, 828 (2021) 142056. 

[4] X. Shen, D. Görzen, Z. Xu, B. Blinn, W. Bleck, T. Beck, U. Krupp, W. Song: Nano-sized Cu precipitation and microstructural evolution in aged ultralow and medium carbon steels. Materialia, 26 (2022) 101626.