A new opportunity for nanopowder forming processes

Abstract

Although a great deal of effort has been made to investigate the sintering behavior of nanopowder compacts, there has been a very limited number of studies dealing with the correlation between the microstructures of green and sintered bodies. This could be attributed to the difficulties in properly the green samples without macro-defects and in lacking in knowledge and experience on the microstructure evolution in nanometer scale. Even though the ultrahigh compaction might provide a forming route to maintain the grain size below 100 nm in fully dense sintered bodies with nanopowder, it is impossible to extend this technique to the engineering components due to limited equipment and tooling. Therefore, it is necessary to reduce the compaction pressure with no or little forming defects in order to fabricate nanostructured sintered bodies of engineering importance. In the present study, attempts have been made to obtain homogeneous green compacts using existing forming techniques and a novel one as well.