Microstructure and rheology of magnetic hybrid materials

该项目的目标是了解磁流变行为，即磁性混合材料（MHM）在磁场中的粘性，粘弹性和弹性行为的变化。这需要研究材料的微观结构变化与其材料性质变化之间的相关性。因此，该项目旨在填补微观结构和流变性能之间的差距，为优先计划内的理论工作组提供有关微观结构的数据以及相应的磁场相关材料性能。关于微观结构变化和通过外部刺激调整材料性质之间的连接的实验和理论结果的结合将使针对某些应用的定制磁性混合材料的合成的新方法成为可能。为此目的，该项目将结合联合收割机磁流变研究，即在磁场中的粘弹性和弹性性能的MHM的测量，与使用X射线显微断层扫描显微结构研究。MHM内部结构的断层扫描检查集中在由外部磁场和机械载荷引起的结构变化上。 由于这些变化可以在单个颗粒水平上检测到微米级颗粒，即对于每个颗粒，可以单独评估几何位置的变化，因此相应的数据可以用作理论研究的基准。在实际项目阶段，我们打算专注于磁场和机械载荷对样品的联合作用。这将为磁流变效应及其微观原因的研究提供真实的多尺度实验手段。结合SPP内的理论研究，这将成为更深层次的多尺度理解这种影响的基础。通过将颗粒位置变化的断层数据与WG Auernhammer在颗粒附近的基质变形数据相结合，将有可能对模型进行更深入的验证。此外，流变学数据可用于提供SPP中面向应用的小组设计原型所需的经验材料定律。

The goal of the project is the understanding of the magnetorheological behaviour, i.e. the change of the viscous, viscoelastic and elastic behaviour of magnetic hybrid materials (MHM) in a magnetic field on a multi scale level. This requires an investigation of the correlation between changes of the microscopic structure of the material and changes of its material properties. Therefore the project is intended to fill the gap between microstructural and rheological properties, providing the theoretically working groups within the priority programme with data concerning the microstructure as well as with the corresponding magnetic field dependent material properties. The combination of experimental and theoretical results concerning the connection between microstructural changes and an adjustment of material properties by external stimuli will enable new methods for synthesis for tailored magnetic hybrid materials for certain applications. For this purpose the project will combine magnetorheological investigations, i.e. measurements of viscoelastic and elastic properties of the MHM in a magnetic field, with microstructural investigations using X-ray micro tomography. The tomographic examination of the inner structure of the MHM focuses on changes of the structure induced by external magnetic fields and mechanical loads. Since these changes can be detected for micron sized particles on a single particle level, i.e. for each particle changes of geometrical position can be evaluated individually, respective data can be used as benchmark for theoretical investigations. In the actual project phase we intend to focus on combined action of magnetic fields and mechanical loads on the samples. This way it will become possible to gain real multi scale experimental approach for the investigation of magnetorheological effects and their microscopic reasons. In combination with theoretical investigations within the SPP this will become the basis for a deeper multi scale understanding of such effects. By combination of tomographic data for changes in particle position with data for deformation of the matrix in the vicinity of the particles by WG Auernhammer an even deeper validation of the models will become possible. Moreover the rheological data can be used to provide empirical material laws needed by the application oriented groups in the SPP for the design of prototypes.