Preparation of nanocrystalline materials by PM methods

Nanocrystalline (nc–)solids with average grain sizes less than 100 nm are most conveniently produced by powder metallurgical methods. This is especially true for reactive powders (e.g. refractive metals) and for powder blends (alloys, composites), where mixtures of the components on a nanometer scale are a prerequisite for obtaining a homogeneous product. We have used the inert gas evaporation as a method to produce and consolidate various elemental powders within a single device. The microstructure of the resulting nc–components (d=20...100 nm) have been correlated with the respective mechanical properties. In general, cold–consolidated ultrafine grained elemental metals are characterized by a remarkably high strength.