Nanocrystalline bulk materials

Nanostructured materials attract considerable scientific and technological interest since they exhibit new and enhanced physical and mechanical properties. In our group nanostructured materials are mainly processed by methods of severe plastic deformation (SPD) such as high pressure torsion and accumulative roll bonding applying deformations up to 100 000%. The focus of our research comprises fundamental aspects of grain refinement, defect evolution and phase stability of the SPD processed nanostructured materials. Bulk nanostructured metals, alloys and intermetallic compounds based on different long-range ordered structures are investigated. The materials are analysed by novel transmission electron microscopy (TEM) methods (like quantitative profile analysis of selected area electron diffraction PASAD) and on an atomic scale using high-resolution TEM. In addition, TEM in-situ methods (straining, heating and cooling) are applied. DSC is used to analyse various phase transformations. The TEM and DSC results are complemented by data obtained by X-ray and synchrotron scattering experiments.