SHS Synthesis and SPS Densification of Nanometric Tungsten

Abstract : Recent studies show that low grain sizes are favorable to improve ductility and machinability in tungsten, as well as the resistance to ablation and spallation if this material is to be used in thermonuclear fusion environment. However, current production routes are not suitable for the fabrication of large bulk nanostructured tungsten samples. The authors propose here a new methodology based on powder metallurgy, including the powder synthesis by the reduction of tungsten trioxide by magnesium using the Self-propagating High-temperature Synthesis process in the presence of a reaction moderator, and the densification procedure. Results show that full tungsten densification may be obtained by SPS at a temperature lower than 1800 °C and that the resulting morphology, keeping a partial nanostructure inherited from the synthesized powders, seems indeed favorable to the use of these materials in fusion environments.