Consolidation and properties of tungsten by spark plasma sintering and hot isostatic pressing

The fabrication of dense tungsten was attempted with the combination process of presintering by spark plasma sintering and final hot isostatic pressing. The specimens fabricated by spark plasma sintering (1500-1600 degrees C) of commercial powder exhibited a relative density above 90.4%. In the case of the post hot isostatic pressing at 1650 degrees C for 2 h, improved relative density in the range of 96.4% to 97.2% was obtained. X-ray diffractometry and X-ray photoelectron spectroscopy analysis indicated that the sintered specimen was composed mainly of tungsten, and the trace amounts of metallic tungsten are bound with oxygen due to the surface oxidation. Strength measurement was conducted by biaxial bending test using a piston-on-three balls. Maximum flexural strength of 761 MPa were obtained for tungsten consolidated by a combined process of spark plasma sintering and hot isostatic pressing. The strength increase is explained by the increase in relative density rather than the effect of particle size.

Automated summary

The study attempted to fabricate dense tungsten using a combination process of spark plasma sintering and hot isostatic pressing, achieving an improvement in relative density and higher strength. X-ray diffractometry and X-ray photoelectron spectroscopy analysis revealed that the specimens were mainly composed of tungsten with trace amounts of metallic tungsten bound with oxygen. The strength testing showed promising results with biaxial bending test.