On the usage of a neutron source to determine the density distribution in compacted cemented carbide powder compounds

ABSTRACT

Density variations in pressed powder materials are of substantial importance and will affect shrinkage and geometry after sintering. It is therefore important to accurately measure this quantity in green bodies. This is emphasised by the fact that the density variation can be used for determining material properties in constitutive mechanical models of compaction. An obvious method to determine the density variation is X-ray tomography. For cemented carbides this is not a possible alternative due to the very high X-ray absorption of tungsten making the samples impossible to penetrate. Neutron radiation has a much higher penetration and this suggests that a neutron source could be used for density distribution determination in such materials. This was investigated currently showing promising results when compared with finite element predictions. It is clear that this approach must be improved to be able to use neutron radiation as a tool for density determination. Improvements are suggested.

KEYWORDS:

• Powder compaction
• sintering
• density distribution
• neutron radiation
• finite element method

Acknowledgement

The authors are grateful to SINE 2020 (funded by the European Union through the H2020 programme) for making it possible to perform the measurements at the Leon Brillouin laboratory where Dr. Frederic Ott was of invaluable assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Hjalmar Staf is Senior Research Engineer at Sandvik Coromant and PhD Student at the Department of Solid Mechanics, Royal Institute of Technology, Stockholm. His main research area is powder pressing technology and powder compaction modelling.

Elias Forssbeck Nyrot is Development Engineer at Sandvik Coromant in Gimo, Sweden. He main area of expertise is Electron Probe Micro Analysis (EPMA), image analysis and X-ray Computed Tomography (XCT).

Per-Lennart Larsson is Professor at the Department of Solid Mechanics, Royal Institute of Technology, Stockholm, Sweden. His main research area is contact mechanics with applications to hardness testing, particle contact and powder compaction.