Combined Mechanical Disordering - Reactive Synthesis, Possible Method of Bulk Nanocrystalline Intermetallics Obtaining

摘要

A promising way to overcome the known drawbacks of intermetallics determined by the high brightness exhibited at ambient temperature, which limits both the possibilities of processing into final products and using in some applications, is their obtaining in a nanocrystalline state. This is possible by Mechanical Alloying (MA), but it leads to the compounds obtaining as fine nanocrystalline powders. Several methods have been proposed to obtain bulk nanocrystalline materials from these powders, without of their consecration. This paper presents a new such a method: combined MA, conducted only to the stage of mechanical disordering - to obtain a nanocrystalline powder mixture, avoiding synthesis reaction, and subsequent compound reactive synthesis combined with powder consolidation. Due to the high energetic state of nanocrystalline powder, both the lasts are possible at a low enough temperature to preserve its nanocrystalline structure in the obtained bulk material. The method has been successfully applied in case of NiAl.