Characteristics of U₃Si and U₃Si₂ Powders Prepared by Centrifugal Atomization

Abstract

The characteristics, that is, morphology, size distribution, alloy phase and microstructure of U₃Si and U₃Si₂ powders, solidified rapidly by a centrifugal atomization, were investigated. The atomized powders consist of spherical particles with a relatively narrow size distribution independent of the alloy composition. The particle size distribution can be controlled by adjusting the atomization parameters such as feeding rates of the melt and revolution speeds of the disk. The major phases of atomized U₃Si and U₃Si₂ powders are α-U and U₃Si₂ and U₃Si₂, respectively. The atomized U₃Si powder has a dendritic structure of very fine and non-faceted U₃Si₂ precipitates with less fibric and eutectic U₃Si₂ structure. The microstructure of U₃Si₂ powder shows a cellular structure with fine U₃Si₂ grains and finely dispersed silicon-rich precipitates. The time for complete peritectoid reaction of the atomized U₃Si particles and the resulting grain size are greatly reduced, due to the refinement of primary U₃Si₂ precipitates.