The Application of Positron Emission Particle Tracking (PEPT) to Study Inclusions in the Casting Process

Abstract

The behavior of inclusions in castings was studied using radioactive labeling of oxide particles located by Positron Emission Particle Tracking (PEPT). This uses the isotope18F, which has a half-life of 110 minutes, and allows particle detection within an accuracy of a few mm. Alumina and glass particles with a size range of 110 to 600 μm were made radioactive by an ion-exchange/surface adsorption process involving irradiated water. Individual radioactive particles were placed in resin-bonded sand moulds at known initial positions, and the moulds were filled with Al alloy, causing the particle to be entrained into the metal stream during the casting process. A modular γ-ray positron camera was used to track the paths of the particles within the mould, demonstrating the applicability of the technique to the study of inclusion behaviour in castings.

Characterization of the latest Birmingham modular positron camera

“…Typical applications of PEPT cover a wide range of granular and particulate systems as well as the study of viscous fluids. A number of industrial processes have been studied using this technique, in particular fluidized beds [10][11][12], mixers, shakers and stirring systems [13] (both pharmaceutical and process equipment), rapid granular flows [14], the motion of fluids, pastes and soft solids (foods) [15,16], and more recently the technique has been applied to the study of the motion of inclusions during the casting of liquid metals [17].…”