Determining the density distribution in cemented carbide powder compacts using 3D neutron imaging

Abstract

Spray-dried refractory carbide and metal powder mixtures, containing tungsten carbide, is compacted and sintered during the production of conventional cutting tool inserts. Since friction between the pressing tool and the powder gives rise to density gradients in the powder compact, shrinkage during sintering is uneven. The shape of the sintered blank is important and can be predicted with finite element (FE) simulations. To validate the simulation of the pressing procedure, the density gradients in the powder compacts must be measured with a high spatial resolution. Since tungsten has a high atomic number, it is hard to penetrate with X-rays and even cold neutrons. We show here that using a polychromatic beam of thermal neutrons, along with beam-hardening correction, such measurements can be successfully realized. The obtained results show good agreement with corresponding FE-simulations. Also, deliberate differences in the compaction process could be verified with the neutron measurements.

One-Step Enameling and Sintering of Low-Carbon Steels

“…Metal powders can be pre-alloyed [44,45] or mechanically alloyed [34,46]; it depends on the application sought. PM seeks added value for use on an industrial scale, such as biomedical implants using wear-resistant titanium alloys [47][48][49] or in the manufacture of hard metals for cutting tools or coatings [50]. Currently, one of its main applications is in the automotive industry for the manufacturing of small and complex components.…”