- Ruhr-Universität Bochum

The hierarchical nature of materials necessitates interdisciplinary materials science

Materials science is an interdisciplinary research field. Its traditional focus on structure-property relationships of structural engineering materials has long been broadened. Today’s materials science comprises materials chemistry and physics, mechanics and thermodynamics of materials. Combinatorial materials research and materials informatics are new fields, which provide valuable new contributions. Materials for medical applications and biological materials and new technologies, like coating procedures and additive manufacturing, are receiving attention. Therefore, materials researchers often belong to different academic departments and have diverse backgrounds. In RUB’s Materials Research Department (MRD), materials researchers from all disciplines with their specific areas of expertise join forces to progress the field. In the past it was quite common that phenomena, which are associated with specific length scales (electronic, atomic, microstructural and macroscopic), were studied separately. Today there is a strong emphasis on understanding scale-bridging aspects of materials science. To this end the hierarchical structure of materials needs to be explored: Electrons form chemical bonds between atoms. Depending on bond chemistry, temperature and pressure the atoms arrange themselves in different ways. For example, atoms form gases and liquids and in the solid state crystals or glasses. The defects of crystalline solids and the arrangement of atoms in an amorphous material have a strong influence on macroscopic material properties. For example, atomic diffusion processes limit the exploitable service life of a superalloy turbine blade. The strength of chemical bonds determines the energy density of batteries. The ability to process materials with atomic scale precision is decisive for electronic transport in semiconductor devices. Thus, materials research is rooted in the hierarchical structure of materials, which promotes the interdisciplinary character of the field. Today, for each hierarchical level/length scale, characterization, processing and simulation methods are available. A key challenge for materials science consists in the design and development of novel materials with desired properties, and the improvement of conventional materials in terms of performance, exploitable service lives and sustainability. This requires bringing together expertise from various fields and well-defined, targeted interdisciplinary research efforts. It further requires the identification of limitations and shortcomings of available methods and, most importantly, establishing bridges between length scales. To this end in particular, data and information from each materials hierarchy need to be aggregated and analyzed. The MRD provides an ideal frame to stimulate this type of interaction. It also aims at acting as a platform for collaborative research efforts, where interdisciplinary expertise is required.

Strategy of the Materials Research Department

Over the past years the MRD has implemented a structure that enables the seamless study of materials across length scales. The Institute of Materials (IM) at RUB acted as a nucleus that was instrumental for establishing the Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) and the RUB Research Centre ZGH (Centre for interface dominated high performance materials). Together the IM, ICAMS and ZGH provide the core expertise and facilities for the MRD that enable the characterization, processing and simulation of materials across all materials hierarchies, a unique characteristic of RUB’s MRD. This core expertise is currently being extended to include data science and materials informatics for a seamless integration of data and information form the different materials hierarchies. The MRD core formed by IM, ICAMS and ZGH provides ample opportunities for research in close collaboration with MRD members that have their main affiliation in other departments and disciplines. Here, MRD promotes the interaction of researchers from different fields and helps to initiate collaborative research. In fact, materials design has become a relevant research topic in other departments of RUB, for example in chemistry, geo-sciences, mathematics, medicine and physics. Diversity is a necessity for vivid exchanges and excellent research collaborations within the MRD. The promotion of early career researchers and their active contributions to MRD research are another key element of the MRD strategy. The MRD seeks to further strengthen materials science expertise at RUB by attracting new faculty members and by further strengthening interdisciplinary interactions not only between all RUB reserarchers with interest in materials research but also with all associated academic colleagues from research institutions close to RUB, like the Max-Planck-Institutes for Iron Research, Coal Research and for Chemical Energy Conversion (MPIE, MPIK and MPICEC), the German Centre for Aerospace Research (DLR) and the Research Centre Jülich (FZ Jülich). It also promotes scientific and technological exchange with research colleagues from R&D departments of the materials industry surrounding RUB. The MRD is coordinating the activities of RUB in the UA Ruhr flagship program Materials Chain, a collaborative research framework of Ruhr-Universität Bochum, the University of Duisburg-Essen and TU Dortmund University. All members of the MRD are also members of the Materials Chain.

In summary MRD’s research strategy focusses on (i) establishing research expertise and facilities for materials science across length scales, (ii) fostering interdisciplinary scientific interactions at RUB integrating nearby institutions and international partners, (iii) promoting early career researchers and (iv) interacting with industrial R&D departments from the Ruhr Area. This forms the basis for our current efforts to coordinate RUB’s next proposal for an excellence cluster in materials science. In this way, MRD contributes to strengthening both, RUB’s visibility in the international scientific materials community as well as RUB’s integration in the technological material developments in our Ruhr Area.

The MRD is a stronghold for research in structural and functional engineering materials, like superalloys, shape memory alloys and advanced steels. New catalytic materials, semiconductors, superconductors and magnetic materials are also important and represent exciting research topics. In recent years, materials issues related to hydrogen technology and sustainable materials technologies have received increased attention. Contributions are made to develop processing routes from atomic layer deposition to bulk samples, including combinatorial high-throughput methods, additive manufacturing and plasma-based methods. These are accompanied by method developments for characterizing and simulating materials across all length scales. Members of the MRD lead a number of large collaborative research projects.

The members of the MRD elect for the duration of two years the speaker of the MRD, the deputy speaker and the MRD board that represents RUB’s materials research. Two science managers assist the speakers in the organization of the MRD and its contributions to the Materials Chain. The members of the MRD are selected based on merit and elected by the MRD general assembly. Among the regular meetings that the MRD organizes are the general assembly, Materials Day, Young Materials Researchers Day, Industry Day as well as workshops and conferences, for example, together with the Materials Chain research framework.