Abstract

The research network High-Performance Bulk Nanocrystalline Materials aims at an in-depth understanding of the physics of synthesis and properties of this novel type of materials. Nanocrystalline materials could initially be obtained only with sub-millimetre dimensions by means of bottom-up synthesis through consolidation of nanocrystalline powders. Recently developed techniques of Severe Plastic Deformation (SPD) allow nanocrystallization within massive bulk materials. These materials can be obtained in units of up to 100 mm and also reveal full density so far impossible for consolidated nanomaterials. These massive, bulk SPD-based nanocrystalline materials exhibit superior mechanical properties compared to conventional nanocrystalline materials, however the understanding of the underlying atomic processes is still low and partially controversial. Functional properties of bulk nanocrystalline materials have scarcely been studied in detail so far.

One focus of the network therefore is an in-depth understanding of the specific mechanical properties of SPD-produced materials in combination with a detailed analysis of the deformation processes relevant for the structural refinement. This will be accomplished by a joint effort of closely co- operating expert groups reaching from synthesis and state-of-the-art atomic-scale characterization to plasticity and modeling. A second focus is on the development of bulk nanocystalline materials with particular functional properties. Here, a key question is whether the excellent soft- and hard-magnetic properties, which are specific for nanostructured materials, can be achieved for bulk materials by SPD-processing. Novel functional property aspects will be, on the one hand, magnetostriction and magnetic shape memory effects of SPD processed nanocrystalline alloys and, on the other hand, variable tunable properties of nanocrystalline materials by manipulating interfacial excess charges. These studies will be supported by a close collaboration with the methodical developments for magnetic characterization of nanocrystalline materials which is also part of this network. Though thenetwork is focussed on SPD-processed materials, alternative routes such as cluster-synthesis or ball- milling will be used for comparison or when method-specific properties are essential.

The network consists of highly recognized Austrian research groups with complementary expertise of synthesis techniques, property analysis and characterization methods of nanocrystalline materials in collaboration with distinguished international partners. In the first period the network will establish a knowledge basis on processing-structure-property relations of bulk nanocrystalline materials which currently represents a major challenge in the materials science community. In its second period, the network should be continued to apply the knowledge basis for optimizing and designing novel bulk
nanomaterials with respect to special physical properties or combinations of them.