Compositionally Complex ThMn12-Type Alloys as Hard Magnetic Materials

• Applicants: Dr. Semih Ener; Dr. Tilmann Hickel
• Subject Area: Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials ; Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale ; Synthesis and Properties of Functional Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562512116

Hard magnetic materials, which are essential for the production of permanent magnets, are indispensable in our daily lives and are widely used in devices such as motors, generators, and sensors. However, a pressing concern stems from the fact that many of these widely used hard magnetic materials rely heavily on elements that are either scarce or geographically limited. This reliance on critical elements becomes particularly problematic in contexts such as wind turbine generators and transportation systems, where these materials must withstand challenging conditions such as high temperatures and significant mechanical stress, potentially undermining their long-term stability. To address this sustainability challenge, it is essential to explore options such as replacing these critical elements with less scarce alternatives or reducing our overall reliance on them. In our project, we address this formidable challenge by employing compositionally complex alloys (CCAs). They offer greater flexibility in terms of chemical composition and an improved phase stability as compared to currently used hard magnets. In this proposal, we investigate the phase stability of ThMn12-type materials combining the insights of accurate theoretical predictions and advanced experimental synthesis and characterization techniques. The primary goal of this project is to design, develop, and study hard magnetic materials that exhibit both high coercivity and phase stability. At the same time, they should be based on chemical combinations with lower criticality indices, such as compositions from naturally abundant ores or recycled materials. To achieve this goal, we use a combinatorial approach of four key strategies: I) To apply CCA design principles to explore the phase stability of hard magnetic ThMn12-type materials, both theoretically and experimentally. II) To analyze the influence of different alloying elements, their concentrations and potential interactions on the magnetic properties of hard-magnetic CCAs. III) To study the effect of processing parameters, including solidification methods, processing routes, and heat treatment, on their microstructure . IV) To develop systematic workflows to evaluate, automize, assess, and generalize the combined approach. This includes the interlink of different software tools and the consideration of experimental and theoretical databases. By leveraging the theoretical and experimental expertise of the project leaders, the application of the combinatorial strategy offers more than just the potential for sustainable, less critical hard magnet materials. The approach is also considered to serve as a springboard for the exploration of novel functional materials beyond the realm of magnetism.

• DFG Programme: Research Grants